libgo: Update to weekly 2011-11-09.

From-SVN: r182073

45 files changed, 18233 insertions, 2 deletions

diff --git a/libgo/go/encoding/asn1/asn1.go b/libgo/go/encoding/asn1/asn1.go
new file mode 100644
index 00000000000..a0066654f8d
--- /dev/null
+++ b/libgo/go/encoding/asn1/asn1.go
@@ -0,0 +1,841 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package asn1 implements parsing of DER-encoded ASN.1 data structures,
+// as defined in ITU-T Rec X.690.
+//
+// See also ``A Layman's Guide to a Subset of ASN.1, BER, and DER,''
+// http://luca.ntop.org/Teaching/Appunti/asn1.html.
+package asn1
+
+// ASN.1 is a syntax for specifying abstract objects and BER, DER, PER, XER etc
+// are different encoding formats for those objects. Here, we'll be dealing
+// with DER, the Distinguished Encoding Rules. DER is used in X.509 because
+// it's fast to parse and, unlike BER, has a unique encoding for every object.
+// When calculating hashes over objects, it's important that the resulting
+// bytes be the same at both ends and DER removes this margin of error.
+//
+// ASN.1 is very complex and this package doesn't attempt to implement
+// everything by any means.
+
+import (
+	"fmt"
+	"math/big"
+	"reflect"
+	"time"
+)
+
+// A StructuralError suggests that the ASN.1 data is valid, but the Go type
+// which is receiving it doesn't match.
+type StructuralError struct {
+	Msg string
+}
+
+func (e StructuralError) Error() string { return "ASN.1 structure error: " + e.Msg }
+
+// A SyntaxError suggests that the ASN.1 data is invalid.
+type SyntaxError struct {
+	Msg string
+}
+
+func (e SyntaxError) Error() string { return "ASN.1 syntax error: " + e.Msg }
+
+// We start by dealing with each of the primitive types in turn.
+
+// BOOLEAN
+
+func parseBool(bytes []byte) (ret bool, err error) {
+	if len(bytes) != 1 {
+		err = SyntaxError{"invalid boolean"}
+		return
+	}
+
+	return bytes[0] != 0, nil
+}
+
+// INTEGER
+
+// parseInt64 treats the given bytes as a big-endian, signed integer and
+// returns the result.
+func parseInt64(bytes []byte) (ret int64, err error) {
+	if len(bytes) > 8 {
+		// We'll overflow an int64 in this case.
+		err = StructuralError{"integer too large"}
+		return
+	}
+	for bytesRead := 0; bytesRead < len(bytes); bytesRead++ {
+		ret <<= 8
+		ret |= int64(bytes[bytesRead])
+	}
+
+	// Shift up and down in order to sign extend the result.
+	ret <<= 64 - uint8(len(bytes))*8
+	ret >>= 64 - uint8(len(bytes))*8
+	return
+}
+
+// parseInt treats the given bytes as a big-endian, signed integer and returns
+// the result.
+func parseInt(bytes []byte) (int, error) {
+	ret64, err := parseInt64(bytes)
+	if err != nil {
+		return 0, err
+	}
+	if ret64 != int64(int(ret64)) {
+		return 0, StructuralError{"integer too large"}
+	}
+	return int(ret64), nil
+}
+
+var bigOne = big.NewInt(1)
+
+// parseBigInt treats the given bytes as a big-endian, signed integer and returns
+// the result.
+func parseBigInt(bytes []byte) *big.Int {
+	ret := new(big.Int)
+	if len(bytes) > 0 && bytes[0]&0x80 == 0x80 {
+		// This is a negative number.
+		notBytes := make([]byte, len(bytes))
+		for i := range notBytes {
+			notBytes[i] = ^bytes[i]
+		}
+		ret.SetBytes(notBytes)
+		ret.Add(ret, bigOne)
+		ret.Neg(ret)
+		return ret
+	}
+	ret.SetBytes(bytes)
+	return ret
+}
+
+// BIT STRING
+
+// BitString is the structure to use when you want an ASN.1 BIT STRING type. A
+// bit string is padded up to the nearest byte in memory and the number of
+// valid bits is recorded. Padding bits will be zero.
+type BitString struct {
+	Bytes     []byte // bits packed into bytes.
+	BitLength int    // length in bits.
+}
+
+// At returns the bit at the given index. If the index is out of range it
+// returns false.
+func (b BitString) At(i int) int {
+	if i < 0 || i >= b.BitLength {
+		return 0
+	}
+	x := i / 8
+	y := 7 - uint(i%8)
+	return int(b.Bytes[x]>>y) & 1
+}
+
+// RightAlign returns a slice where the padding bits are at the beginning. The
+// slice may share memory with the BitString.
+func (b BitString) RightAlign() []byte {
+	shift := uint(8 - (b.BitLength % 8))
+	if shift == 8 || len(b.Bytes) == 0 {
+		return b.Bytes
+	}
+
+	a := make([]byte, len(b.Bytes))
+	a[0] = b.Bytes[0] >> shift
+	for i := 1; i < len(b.Bytes); i++ {
+		a[i] = b.Bytes[i-1] << (8 - shift)
+		a[i] |= b.Bytes[i] >> shift
+	}
+
+	return a
+}
+
+// parseBitString parses an ASN.1 bit string from the given byte slice and returns it.
+func parseBitString(bytes []byte) (ret BitString, err error) {
+	if len(bytes) == 0 {
+		err = SyntaxError{"zero length BIT STRING"}
+		return
+	}
+	paddingBits := int(bytes[0])
+	if paddingBits > 7 ||
+		len(bytes) == 1 && paddingBits > 0 ||
+		bytes[len(bytes)-1]&((1<<bytes[0])-1) != 0 {
+		err = SyntaxError{"invalid padding bits in BIT STRING"}
+		return
+	}
+	ret.BitLength = (len(bytes)-1)*8 - paddingBits
+	ret.Bytes = bytes[1:]
+	return
+}
+
+// OBJECT IDENTIFIER
+
+// An ObjectIdentifier represents an ASN.1 OBJECT IDENTIFIER.
+type ObjectIdentifier []int
+
+// Equal returns true iff oi and other represent the same identifier.
+func (oi ObjectIdentifier) Equal(other ObjectIdentifier) bool {
+	if len(oi) != len(other) {
+		return false
+	}
+	for i := 0; i < len(oi); i++ {
+		if oi[i] != other[i] {
+			return false
+		}
+	}
+
+	return true
+}
+
+// parseObjectIdentifier parses an OBJECT IDENTIFIER from the given bytes and
+// returns it. An object identifier is a sequence of variable length integers
+// that are assigned in a hierarchy.
+func parseObjectIdentifier(bytes []byte) (s []int, err error) {
+	if len(bytes) == 0 {
+		err = SyntaxError{"zero length OBJECT IDENTIFIER"}
+		return
+	}
+
+	// In the worst case, we get two elements from the first byte (which is
+	// encoded differently) and then every varint is a single byte long.
+	s = make([]int, len(bytes)+1)
+
+	// The first byte is 40*value1 + value2:
+	s[0] = int(bytes[0]) / 40
+	s[1] = int(bytes[0]) % 40
+	i := 2
+	for offset := 1; offset < len(bytes); i++ {
+		var v int
+		v, offset, err = parseBase128Int(bytes, offset)
+		if err != nil {
+			return
+		}
+		s[i] = v
+	}
+	s = s[0:i]
+	return
+}
+
+// ENUMERATED
+
+// An Enumerated is represented as a plain int.
+type Enumerated int
+
+// FLAG
+
+// A Flag accepts any data and is set to true if present.
+type Flag bool
+
+// parseBase128Int parses a base-128 encoded int from the given offset in the
+// given byte slice. It returns the value and the new offset.
+func parseBase128Int(bytes []byte, initOffset int) (ret, offset int, err error) {
+	offset = initOffset
+	for shifted := 0; offset < len(bytes); shifted++ {
+		if shifted > 4 {
+			err = StructuralError{"base 128 integer too large"}
+			return
+		}
+		ret <<= 7
+		b := bytes[offset]
+		ret |= int(b & 0x7f)
+		offset++
+		if b&0x80 == 0 {
+			return
+		}
+	}
+	err = SyntaxError{"truncated base 128 integer"}
+	return
+}
+
+// UTCTime
+
+func parseUTCTime(bytes []byte) (ret *time.Time, err error) {
+	s := string(bytes)
+	ret, err = time.Parse("0601021504Z0700", s)
+	if err == nil {
+		return
+	}
+	ret, err = time.Parse("060102150405Z0700", s)
+	return
+}
+
+// parseGeneralizedTime parses the GeneralizedTime from the given byte slice
+// and returns the resulting time.
+func parseGeneralizedTime(bytes []byte) (ret *time.Time, err error) {
+	return time.Parse("20060102150405Z0700", string(bytes))
+}
+
+// PrintableString
+
+// parsePrintableString parses a ASN.1 PrintableString from the given byte
+// array and returns it.
+func parsePrintableString(bytes []byte) (ret string, err error) {
+	for _, b := range bytes {
+		if !isPrintable(b) {
+			err = SyntaxError{"PrintableString contains invalid character"}
+			return
+		}
+	}
+	ret = string(bytes)
+	return
+}
+
+// isPrintable returns true iff the given b is in the ASN.1 PrintableString set.
+func isPrintable(b byte) bool {
+	return 'a' <= b && b <= 'z' ||
+		'A' <= b && b <= 'Z' ||
+		'0' <= b && b <= '9' ||
+		'\'' <= b && b <= ')' ||
+		'+' <= b && b <= '/' ||
+		b == ' ' ||
+		b == ':' ||
+		b == '=' ||
+		b == '?' ||
+		// This is technically not allowed in a PrintableString.
+		// However, x509 certificates with wildcard strings don't
+		// always use the correct string type so we permit it.
+		b == '*'
+}
+
+// IA5String
+
+// parseIA5String parses a ASN.1 IA5String (ASCII string) from the given
+// byte slice and returns it.
+func parseIA5String(bytes []byte) (ret string, err error) {
+	for _, b := range bytes {
+		if b >= 0x80 {
+			err = SyntaxError{"IA5String contains invalid character"}
+			return
+		}
+	}
+	ret = string(bytes)
+	return
+}
+
+// T61String
+
+// parseT61String parses a ASN.1 T61String (8-bit clean string) from the given
+// byte slice and returns it.
+func parseT61String(bytes []byte) (ret string, err error) {
+	return string(bytes), nil
+}
+
+// UTF8String
+
+// parseUTF8String parses a ASN.1 UTF8String (raw UTF-8) from the given byte
+// array and returns it.
+func parseUTF8String(bytes []byte) (ret string, err error) {
+	return string(bytes), nil
+}
+
+// A RawValue represents an undecoded ASN.1 object.
+type RawValue struct {
+	Class, Tag int
+	IsCompound bool
+	Bytes      []byte
+	FullBytes  []byte // includes the tag and length
+}
+
+// RawContent is used to signal that the undecoded, DER data needs to be
+// preserved for a struct. To use it, the first field of the struct must have
+// this type. It's an error for any of the other fields to have this type.
+type RawContent []byte
+
+// Tagging
+
+// parseTagAndLength parses an ASN.1 tag and length pair from the given offset
+// into a byte slice. It returns the parsed data and the new offset. SET and
+// SET OF (tag 17) are mapped to SEQUENCE and SEQUENCE OF (tag 16) since we
+// don't distinguish between ordered and unordered objects in this code.
+func parseTagAndLength(bytes []byte, initOffset int) (ret tagAndLength, offset int, err error) {
+	offset = initOffset
+	b := bytes[offset]
+	offset++
+	ret.class = int(b >> 6)
+	ret.isCompound = b&0x20 == 0x20
+	ret.tag = int(b & 0x1f)
+
+	// If the bottom five bits are set, then the tag number is actually base 128
+	// encoded afterwards
+	if ret.tag == 0x1f {
+		ret.tag, offset, err = parseBase128Int(bytes, offset)
+		if err != nil {
+			return
+		}
+	}
+	if offset >= len(bytes) {
+		err = SyntaxError{"truncated tag or length"}
+		return
+	}
+	b = bytes[offset]
+	offset++
+	if b&0x80 == 0 {
+		// The length is encoded in the bottom 7 bits.
+		ret.length = int(b & 0x7f)
+	} else {
+		// Bottom 7 bits give the number of length bytes to follow.
+		numBytes := int(b & 0x7f)
+		// We risk overflowing a signed 32-bit number if we accept more than 3 bytes.
+		if numBytes > 3 {
+			err = StructuralError{"length too large"}
+			return
+		}
+		if numBytes == 0 {
+			err = SyntaxError{"indefinite length found (not DER)"}
+			return
+		}
+		ret.length = 0
+		for i := 0; i < numBytes; i++ {
+			if offset >= len(bytes) {
+				err = SyntaxError{"truncated tag or length"}
+				return
+			}
+			b = bytes[offset]
+			offset++
+			ret.length <<= 8
+			ret.length |= int(b)
+		}
+	}
+
+	return
+}
+
+// parseSequenceOf is used for SEQUENCE OF and SET OF values. It tries to parse
+// a number of ASN.1 values from the given byte slice and returns them as a
+// slice of Go values of the given type.
+func parseSequenceOf(bytes []byte, sliceType reflect.Type, elemType reflect.Type) (ret reflect.Value, err error) {
+	expectedTag, compoundType, ok := getUniversalType(elemType)
+	if !ok {
+		err = StructuralError{"unknown Go type for slice"}
+		return
+	}
+
+	// First we iterate over the input and count the number of elements,
+	// checking that the types are correct in each case.
+	numElements := 0
+	for offset := 0; offset < len(bytes); {
+		var t tagAndLength
+		t, offset, err = parseTagAndLength(bytes, offset)
+		if err != nil {
+			return
+		}
+		// We pretend that GENERAL STRINGs are PRINTABLE STRINGs so
+		// that a sequence of them can be parsed into a []string.
+		if t.tag == tagGeneralString {
+			t.tag = tagPrintableString
+		}
+		if t.class != classUniversal || t.isCompound != compoundType || t.tag != expectedTag {
+			err = StructuralError{"sequence tag mismatch"}
+			return
+		}
+		if invalidLength(offset, t.length, len(bytes)) {
+			err = SyntaxError{"truncated sequence"}
+			return
+		}
+		offset += t.length
+		numElements++
+	}
+	ret = reflect.MakeSlice(sliceType, numElements, numElements)
+	params := fieldParameters{}
+	offset := 0
+	for i := 0; i < numElements; i++ {
+		offset, err = parseField(ret.Index(i), bytes, offset, params)
+		if err != nil {
+			return
+		}
+	}
+	return
+}
+
+var (
+	bitStringType        = reflect.TypeOf(BitString{})
+	objectIdentifierType = reflect.TypeOf(ObjectIdentifier{})
+	enumeratedType       = reflect.TypeOf(Enumerated(0))
+	flagType             = reflect.TypeOf(Flag(false))
+	timeType             = reflect.TypeOf(&time.Time{})
+	rawValueType         = reflect.TypeOf(RawValue{})
+	rawContentsType      = reflect.TypeOf(RawContent(nil))
+	bigIntType           = reflect.TypeOf(new(big.Int))
+)
+
+// invalidLength returns true iff offset + length > sliceLength, or if the
+// addition would overflow.
+func invalidLength(offset, length, sliceLength int) bool {
+	return offset+length < offset || offset+length > sliceLength
+}
+
+// parseField is the main parsing function. Given a byte slice and an offset
+// into the array, it will try to parse a suitable ASN.1 value out and store it
+// in the given Value.
+func parseField(v reflect.Value, bytes []byte, initOffset int, params fieldParameters) (offset int, err error) {
+	offset = initOffset
+	fieldType := v.Type()
+
+	// If we have run out of data, it may be that there are optional elements at the end.
+	if offset == len(bytes) {
+		if !setDefaultValue(v, params) {
+			err = SyntaxError{"sequence truncated"}
+		}
+		return
+	}
+
+	// Deal with raw values.
+	if fieldType == rawValueType {
+		var t tagAndLength
+		t, offset, err = parseTagAndLength(bytes, offset)
+		if err != nil {
+			return
+		}
+		if invalidLength(offset, t.length, len(bytes)) {
+			err = SyntaxError{"data truncated"}
+			return
+		}
+		result := RawValue{t.class, t.tag, t.isCompound, bytes[offset : offset+t.length], bytes[initOffset : offset+t.length]}
+		offset += t.length
+		v.Set(reflect.ValueOf(result))
+		return
+	}
+
+	// Deal with the ANY type.
+	if ifaceType := fieldType; ifaceType.Kind() == reflect.Interface && ifaceType.NumMethod() == 0 {
+		var t tagAndLength
+		t, offset, err = parseTagAndLength(bytes, offset)
+		if err != nil {
+			return
+		}
+		if invalidLength(offset, t.length, len(bytes)) {
+			err = SyntaxError{"data truncated"}
+			return
+		}
+		var result interface{}
+		if !t.isCompound && t.class == classUniversal {
+			innerBytes := bytes[offset : offset+t.length]
+			switch t.tag {
+			case tagPrintableString:
+				result, err = parsePrintableString(innerBytes)
+			case tagIA5String:
+				result, err = parseIA5String(innerBytes)
+			case tagT61String:
+				result, err = parseT61String(innerBytes)
+			case tagUTF8String:
+				result, err = parseUTF8String(innerBytes)
+			case tagInteger:
+				result, err = parseInt64(innerBytes)
+			case tagBitString:
+				result, err = parseBitString(innerBytes)
+			case tagOID:
+				result, err = parseObjectIdentifier(innerBytes)
+			case tagUTCTime:
+				result, err = parseUTCTime(innerBytes)
+			case tagOctetString:
+				result = innerBytes
+			default:
+				// If we don't know how to handle the type, we just leave Value as nil.
+			}
+		}
+		offset += t.length
+		if err != nil {
+			return
+		}
+		if result != nil {
+			v.Set(reflect.ValueOf(result))
+		}
+		return
+	}
+	universalTag, compoundType, ok1 := getUniversalType(fieldType)
+	if !ok1 {
+		err = StructuralError{fmt.Sprintf("unknown Go type: %v", fieldType)}
+		return
+	}
+
+	t, offset, err := parseTagAndLength(bytes, offset)
+	if err != nil {
+		return
+	}
+	if params.explicit {
+		expectedClass := classContextSpecific
+		if params.application {
+			expectedClass = classApplication
+		}
+		if t.class == expectedClass && t.tag == *params.tag && (t.length == 0 || t.isCompound) {
+			if t.length > 0 {
+				t, offset, err = parseTagAndLength(bytes, offset)
+				if err != nil {
+					return
+				}
+			} else {
+				if fieldType != flagType {
+					err = StructuralError{"Zero length explicit tag was not an asn1.Flag"}
+					return
+				}
+				v.SetBool(true)
+				return
+			}
+		} else {
+			// The tags didn't match, it might be an optional element.
+			ok := setDefaultValue(v, params)
+			if ok {
+				offset = initOffset
+			} else {
+				err = StructuralError{"explicitly tagged member didn't match"}
+			}
+			return
+		}
+	}
+
+	// Special case for strings: all the ASN.1 string types map to the Go
+	// type string. getUniversalType returns the tag for PrintableString
+	// when it sees a string, so if we see a different string type on the
+	// wire, we change the universal type to match.
+	if universalTag == tagPrintableString {
+		switch t.tag {
+		case tagIA5String, tagGeneralString, tagT61String, tagUTF8String:
+			universalTag = t.tag
+		}
+	}
+
+	// Special case for time: UTCTime and GeneralizedTime both map to the
+	// Go type time.Time.
+	if universalTag == tagUTCTime && t.tag == tagGeneralizedTime {
+		universalTag = tagGeneralizedTime
+	}
+
+	expectedClass := classUniversal
+	expectedTag := universalTag
+
+	if !params.explicit && params.tag != nil {
+		expectedClass = classContextSpecific
+		expectedTag = *params.tag
+	}
+
+	if !params.explicit && params.application && params.tag != nil {
+		expectedClass = classApplication
+		expectedTag = *params.tag
+	}
+
+	// We have unwrapped any explicit tagging at this point.
+	if t.class != expectedClass || t.tag != expectedTag || t.isCompound != compoundType {
+		// Tags don't match. Again, it could be an optional element.
+		ok := setDefaultValue(v, params)
+		if ok {
+			offset = initOffset
+		} else {
+			err = StructuralError{fmt.Sprintf("tags don't match (%d vs %+v) %+v %s @%d", expectedTag, t, params, fieldType.Name(), offset)}
+		}
+		return
+	}
+	if invalidLength(offset, t.length, len(bytes)) {
+		err = SyntaxError{"data truncated"}
+		return
+	}
+	innerBytes := bytes[offset : offset+t.length]
+	offset += t.length
+
+	// We deal with the structures defined in this package first.
+	switch fieldType {
+	case objectIdentifierType:
+		newSlice, err1 := parseObjectIdentifier(innerBytes)
+		v.Set(reflect.MakeSlice(v.Type(), len(newSlice), len(newSlice)))
+		if err1 == nil {
+			reflect.Copy(v, reflect.ValueOf(newSlice))
+		}
+		err = err1
+		return
+	case bitStringType:
+		bs, err1 := parseBitString(innerBytes)
+		if err1 == nil {
+			v.Set(reflect.ValueOf(bs))
+		}
+		err = err1
+		return
+	case timeType:
+		var time *time.Time
+		var err1 error
+		if universalTag == tagUTCTime {
+			time, err1 = parseUTCTime(innerBytes)
+		} else {
+			time, err1 = parseGeneralizedTime(innerBytes)
+		}
+		if err1 == nil {
+			v.Set(reflect.ValueOf(time))
+		}
+		err = err1
+		return
+	case enumeratedType:
+		parsedInt, err1 := parseInt(innerBytes)
+		if err1 == nil {
+			v.SetInt(int64(parsedInt))
+		}
+		err = err1
+		return
+	case flagType:
+		v.SetBool(true)
+		return
+	case bigIntType:
+		parsedInt := parseBigInt(innerBytes)
+		v.Set(reflect.ValueOf(parsedInt))
+		return
+	}
+	switch val := v; val.Kind() {
+	case reflect.Bool:
+		parsedBool, err1 := parseBool(innerBytes)
+		if err1 == nil {
+			val.SetBool(parsedBool)
+		}
+		err = err1
+		return
+	case reflect.Int, reflect.Int32:
+		parsedInt, err1 := parseInt(innerBytes)
+		if err1 == nil {
+			val.SetInt(int64(parsedInt))
+		}
+		err = err1
+		return
+	case reflect.Int64:
+		parsedInt, err1 := parseInt64(innerBytes)
+		if err1 == nil {
+			val.SetInt(parsedInt)
+		}
+		err = err1
+		return
+	// TODO(dfc) Add support for the remaining integer types
+	case reflect.Struct:
+		structType := fieldType
+
+		if structType.NumField() > 0 &&
+			structType.Field(0).Type == rawContentsType {
+			bytes := bytes[initOffset:offset]
+			val.Field(0).Set(reflect.ValueOf(RawContent(bytes)))
+		}
+
+		innerOffset := 0
+		for i := 0; i < structType.NumField(); i++ {
+			field := structType.Field(i)
+			if i == 0 && field.Type == rawContentsType {
+				continue
+			}
+			innerOffset, err = parseField(val.Field(i), innerBytes, innerOffset, parseFieldParameters(field.Tag.Get("asn1")))
+			if err != nil {
+				return
+			}
+		}
+		// We allow extra bytes at the end of the SEQUENCE because
+		// adding elements to the end has been used in X.509 as the
+		// version numbers have increased.
+		return
+	case reflect.Slice:
+		sliceType := fieldType
+		if sliceType.Elem().Kind() == reflect.Uint8 {
+			val.Set(reflect.MakeSlice(sliceType, len(innerBytes), len(innerBytes)))
+			reflect.Copy(val, reflect.ValueOf(innerBytes))
+			return
+		}
+		newSlice, err1 := parseSequenceOf(innerBytes, sliceType, sliceType.Elem())
+		if err1 == nil {
+			val.Set(newSlice)
+		}
+		err = err1
+		return
+	case reflect.String:
+		var v string
+		switch universalTag {
+		case tagPrintableString:
+			v, err = parsePrintableString(innerBytes)
+		case tagIA5String:
+			v, err = parseIA5String(innerBytes)
+		case tagT61String:
+			v, err = parseT61String(innerBytes)
+		case tagUTF8String:
+			v, err = parseUTF8String(innerBytes)
+		case tagGeneralString:
+			// GeneralString is specified in ISO-2022/ECMA-35,
+			// A brief review suggests that it includes structures
+			// that allow the encoding to change midstring and
+			// such. We give up and pass it as an 8-bit string.
+			v, err = parseT61String(innerBytes)
+		default:
+			err = SyntaxError{fmt.Sprintf("internal error: unknown string type %d", universalTag)}
+		}
+		if err == nil {
+			val.SetString(v)
+		}
+		return
+	}
+	err = StructuralError{"unsupported: " + v.Type().String()}
+	return
+}
+
+// setDefaultValue is used to install a default value, from a tag string, into
+// a Value. It is successful is the field was optional, even if a default value
+// wasn't provided or it failed to install it into the Value.
+func setDefaultValue(v reflect.Value, params fieldParameters) (ok bool) {
+	if !params.optional {
+		return
+	}
+	ok = true
+	if params.defaultValue == nil {
+		return
+	}
+	switch val := v; val.Kind() {
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		val.SetInt(*params.defaultValue)
+	}
+	return
+}
+
+// Unmarshal parses the DER-encoded ASN.1 data structure b
+// and uses the reflect package to fill in an arbitrary value pointed at by val.
+// Because Unmarshal uses the reflect package, the structs
+// being written to must use upper case field names.
+//
+// An ASN.1 INTEGER can be written to an int, int32 or int64.
+// If the encoded value does not fit in the Go type,
+// Unmarshal returns a parse error.
+//
+// An ASN.1 BIT STRING can be written to a BitString.
+//
+// An ASN.1 OCTET STRING can be written to a []byte.
+//
+// An ASN.1 OBJECT IDENTIFIER can be written to an
+// ObjectIdentifier.
+//
+// An ASN.1 ENUMERATED can be written to an Enumerated.
+//
+// An ASN.1 UTCTIME or GENERALIZEDTIME can be written to a *time.Time.
+//
+// An ASN.1 PrintableString or IA5String can be written to a string.
+//
+// Any of the above ASN.1 values can be written to an interface{}.
+// The value stored in the interface has the corresponding Go type.
+// For integers, that type is int64.
+//
+// An ASN.1 SEQUENCE OF x or SET OF x can be written
+// to a slice if an x can be written to the slice's element type.
+//
+// An ASN.1 SEQUENCE or SET can be written to a struct
+// if each of the elements in the sequence can be
+// written to the corresponding element in the struct.
+//
+// The following tags on struct fields have special meaning to Unmarshal:
+//
+//	optional		marks the field as ASN.1 OPTIONAL
+//	[explicit] tag:x	specifies the ASN.1 tag number; implies ASN.1 CONTEXT SPECIFIC
+//	default:x		sets the default value for optional integer fields
+//
+// If the type of the first field of a structure is RawContent then the raw
+// ASN1 contents of the struct will be stored in it.
+//
+// Other ASN.1 types are not supported; if it encounters them,
+// Unmarshal returns a parse error.
+func Unmarshal(b []byte, val interface{}) (rest []byte, err error) {
+	return UnmarshalWithParams(b, val, "")
+}
+
+// UnmarshalWithParams allows field parameters to be specified for the
+// top-level element. The form of the params is the same as the field tags.
+func UnmarshalWithParams(b []byte, val interface{}, params string) (rest []byte, err error) {
+	v := reflect.ValueOf(val).Elem()
+	offset, err := parseField(v, b, 0, parseFieldParameters(params))
+	if err != nil {
+		return nil, err
+	}
+	return b[offset:], nil
+}
diff --git a/libgo/go/encoding/asn1/asn1_test.go b/libgo/go/encoding/asn1/asn1_test.go
new file mode 100644
index 00000000000..1c529bdb30c
--- /dev/null
+++ b/libgo/go/encoding/asn1/asn1_test.go
@@ -0,0 +1,689 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package asn1
+
+import (
+	"bytes"
+	"reflect"
+	"testing"
+	"time"
+)
+
+type int64Test struct {
+	in  []byte
+	ok  bool
+	out int64
+}
+
+var int64TestData = []int64Test{
+	{[]byte{0x00}, true, 0},
+	{[]byte{0x7f}, true, 127},
+	{[]byte{0x00, 0x80}, true, 128},
+	{[]byte{0x01, 0x00}, true, 256},
+	{[]byte{0x80}, true, -128},
+	{[]byte{0xff, 0x7f}, true, -129},
+	{[]byte{0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff}, true, -1},
+	{[]byte{0xff}, true, -1},
+	{[]byte{0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}, true, -9223372036854775808},
+	{[]byte{0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}, false, 0},
+}
+
+func TestParseInt64(t *testing.T) {
+	for i, test := range int64TestData {
+		ret, err := parseInt64(test.in)
+		if (err == nil) != test.ok {
+			t.Errorf("#%d: Incorrect error result (did fail? %v, expected: %v)", i, err == nil, test.ok)
+		}
+		if test.ok && ret != test.out {
+			t.Errorf("#%d: Bad result: %v (expected %v)", i, ret, test.out)
+		}
+	}
+}
+
+type int32Test struct {
+	in  []byte
+	ok  bool
+	out int32
+}
+
+var int32TestData = []int32Test{
+	{[]byte{0x00}, true, 0},
+	{[]byte{0x7f}, true, 127},
+	{[]byte{0x00, 0x80}, true, 128},
+	{[]byte{0x01, 0x00}, true, 256},
+	{[]byte{0x80}, true, -128},
+	{[]byte{0xff, 0x7f}, true, -129},
+	{[]byte{0xff, 0xff, 0xff, 0xff}, true, -1},
+	{[]byte{0xff}, true, -1},
+	{[]byte{0x80, 0x00, 0x00, 0x00}, true, -2147483648},
+	{[]byte{0x80, 0x00, 0x00, 0x00, 0x00}, false, 0},
+}
+
+func TestParseInt32(t *testing.T) {
+	for i, test := range int32TestData {
+		ret, err := parseInt(test.in)
+		if (err == nil) != test.ok {
+			t.Errorf("#%d: Incorrect error result (did fail? %v, expected: %v)", i, err == nil, test.ok)
+		}
+		if test.ok && int32(ret) != test.out {
+			t.Errorf("#%d: Bad result: %v (expected %v)", i, ret, test.out)
+		}
+	}
+}
+
+var bigIntTests = []struct {
+	in     []byte
+	base10 string
+}{
+	{[]byte{0xff}, "-1"},
+	{[]byte{0x00}, "0"},
+	{[]byte{0x01}, "1"},
+	{[]byte{0x00, 0xff}, "255"},
+	{[]byte{0xff, 0x00}, "-256"},
+	{[]byte{0x01, 0x00}, "256"},
+}
+
+func TestParseBigInt(t *testing.T) {
+	for i, test := range bigIntTests {
+		ret := parseBigInt(test.in)
+		if ret.String() != test.base10 {
+			t.Errorf("#%d: bad result from %x, got %s want %s", i, test.in, ret.String(), test.base10)
+		}
+		fw := newForkableWriter()
+		marshalBigInt(fw, ret)
+		result := fw.Bytes()
+		if !bytes.Equal(result, test.in) {
+			t.Errorf("#%d: got %x from marshaling %s, want %x", i, result, ret, test.in)
+		}
+	}
+}
+
+type bitStringTest struct {
+	in        []byte
+	ok        bool
+	out       []byte
+	bitLength int
+}
+
+var bitStringTestData = []bitStringTest{
+	{[]byte{}, false, []byte{}, 0},
+	{[]byte{0x00}, true, []byte{}, 0},
+	{[]byte{0x07, 0x00}, true, []byte{0x00}, 1},
+	{[]byte{0x07, 0x01}, false, []byte{}, 0},
+	{[]byte{0x07, 0x40}, false, []byte{}, 0},
+	{[]byte{0x08, 0x00}, false, []byte{}, 0},
+}
+
+func TestBitString(t *testing.T) {
+	for i, test := range bitStringTestData {
+		ret, err := parseBitString(test.in)
+		if (err == nil) != test.ok {
+			t.Errorf("#%d: Incorrect error result (did fail? %v, expected: %v)", i, err == nil, test.ok)
+		}
+		if err == nil {
+			if test.bitLength != ret.BitLength || bytes.Compare(ret.Bytes, test.out) != 0 {
+				t.Errorf("#%d: Bad result: %v (expected %v %v)", i, ret, test.out, test.bitLength)
+			}
+		}
+	}
+}
+
+func TestBitStringAt(t *testing.T) {
+	bs := BitString{[]byte{0x82, 0x40}, 16}
+	if bs.At(0) != 1 {
+		t.Error("#1: Failed")
+	}
+	if bs.At(1) != 0 {
+		t.Error("#2: Failed")
+	}
+	if bs.At(6) != 1 {
+		t.Error("#3: Failed")
+	}
+	if bs.At(9) != 1 {
+		t.Error("#4: Failed")
+	}
+}
+
+type bitStringRightAlignTest struct {
+	in    []byte
+	inlen int
+	out   []byte
+}
+
+var bitStringRightAlignTests = []bitStringRightAlignTest{
+	{[]byte{0x80}, 1, []byte{0x01}},
+	{[]byte{0x80, 0x80}, 9, []byte{0x01, 0x01}},
+	{[]byte{}, 0, []byte{}},
+	{[]byte{0xce}, 8, []byte{0xce}},
+	{[]byte{0xce, 0x47}, 16, []byte{0xce, 0x47}},
+	{[]byte{0x34, 0x50}, 12, []byte{0x03, 0x45}},
+}
+
+func TestBitStringRightAlign(t *testing.T) {
+	for i, test := range bitStringRightAlignTests {
+		bs := BitString{test.in, test.inlen}
+		out := bs.RightAlign()
+		if bytes.Compare(out, test.out) != 0 {
+			t.Errorf("#%d got: %x want: %x", i, out, test.out)
+		}
+	}
+}
+
+type objectIdentifierTest struct {
+	in  []byte
+	ok  bool
+	out []int
+}
+
+var objectIdentifierTestData = []objectIdentifierTest{
+	{[]byte{}, false, []int{}},
+	{[]byte{85}, true, []int{2, 5}},
+	{[]byte{85, 0x02}, true, []int{2, 5, 2}},
+	{[]byte{85, 0x02, 0xc0, 0x00}, true, []int{2, 5, 2, 0x2000}},
+	{[]byte{85, 0x02, 0xc0, 0x80, 0x80, 0x80, 0x80}, false, []int{}},
+}
+
+func TestObjectIdentifier(t *testing.T) {
+	for i, test := range objectIdentifierTestData {
+		ret, err := parseObjectIdentifier(test.in)
+		if (err == nil) != test.ok {
+			t.Errorf("#%d: Incorrect error result (did fail? %v, expected: %v)", i, err == nil, test.ok)
+		}
+		if err == nil {
+			if !reflect.DeepEqual(test.out, ret) {
+				t.Errorf("#%d: Bad result: %v (expected %v)", i, ret, test.out)
+			}
+		}
+	}
+}
+
+type timeTest struct {
+	in  string
+	ok  bool
+	out *time.Time
+}
+
+var utcTestData = []timeTest{
+	{"910506164540-0700", true, &time.Time{1991, 05, 06, 16, 45, 40, 0, -7 * 60 * 60, ""}},
+	{"910506164540+0730", true, &time.Time{1991, 05, 06, 16, 45, 40, 0, 7*60*60 + 30*60, ""}},
+	{"910506234540Z", true, &time.Time{1991, 05, 06, 23, 45, 40, 0, 0, "UTC"}},
+	{"9105062345Z", true, &time.Time{1991, 05, 06, 23, 45, 0, 0, 0, "UTC"}},
+	{"a10506234540Z", false, nil},
+	{"91a506234540Z", false, nil},
+	{"9105a6234540Z", false, nil},
+	{"910506a34540Z", false, nil},
+	{"910506334a40Z", false, nil},
+	{"91050633444aZ", false, nil},
+	{"910506334461Z", false, nil},
+	{"910506334400Za", false, nil},
+}
+
+func TestUTCTime(t *testing.T) {
+	for i, test := range utcTestData {
+		ret, err := parseUTCTime([]byte(test.in))
+		if (err == nil) != test.ok {
+			t.Errorf("#%d: Incorrect error result (did fail? %v, expected: %v)", i, err == nil, test.ok)
+		}
+		if err == nil {
+			if !reflect.DeepEqual(test.out, ret) {
+				t.Errorf("#%d: Bad result: %v (expected %v)", i, ret, test.out)
+			}
+		}
+	}
+}
+
+var generalizedTimeTestData = []timeTest{
+	{"20100102030405Z", true, &time.Time{2010, 01, 02, 03, 04, 05, 0, 0, "UTC"}},
+	{"20100102030405", false, nil},
+	{"20100102030405+0607", true, &time.Time{2010, 01, 02, 03, 04, 05, 0, 6*60*60 + 7*60, ""}},
+	{"20100102030405-0607", true, &time.Time{2010, 01, 02, 03, 04, 05, 0, -6*60*60 - 7*60, ""}},
+}
+
+func TestGeneralizedTime(t *testing.T) {
+	for i, test := range generalizedTimeTestData {
+		ret, err := parseGeneralizedTime([]byte(test.in))
+		if (err == nil) != test.ok {
+			t.Errorf("#%d: Incorrect error result (did fail? %v, expected: %v)", i, err == nil, test.ok)
+		}
+		if err == nil {
+			if !reflect.DeepEqual(test.out, ret) {
+				t.Errorf("#%d: Bad result: %v (expected %v)", i, ret, test.out)
+			}
+		}
+	}
+}
+
+type tagAndLengthTest struct {
+	in  []byte
+	ok  bool
+	out tagAndLength
+}
+
+var tagAndLengthData = []tagAndLengthTest{
+	{[]byte{0x80, 0x01}, true, tagAndLength{2, 0, 1, false}},
+	{[]byte{0xa0, 0x01}, true, tagAndLength{2, 0, 1, true}},
+	{[]byte{0x02, 0x00}, true, tagAndLength{0, 2, 0, false}},
+	{[]byte{0xfe, 0x00}, true, tagAndLength{3, 30, 0, true}},
+	{[]byte{0x1f, 0x01, 0x00}, true, tagAndLength{0, 1, 0, false}},
+	{[]byte{0x1f, 0x81, 0x00, 0x00}, true, tagAndLength{0, 128, 0, false}},
+	{[]byte{0x1f, 0x81, 0x80, 0x01, 0x00}, true, tagAndLength{0, 0x4001, 0, false}},
+	{[]byte{0x00, 0x81, 0x01}, true, tagAndLength{0, 0, 1, false}},
+	{[]byte{0x00, 0x82, 0x01, 0x00}, true, tagAndLength{0, 0, 256, false}},
+	{[]byte{0x00, 0x83, 0x01, 0x00}, false, tagAndLength{}},
+	{[]byte{0x1f, 0x85}, false, tagAndLength{}},
+	{[]byte{0x30, 0x80}, false, tagAndLength{}},
+}
+
+func TestParseTagAndLength(t *testing.T) {
+	for i, test := range tagAndLengthData {
+		tagAndLength, _, err := parseTagAndLength(test.in, 0)
+		if (err == nil) != test.ok {
+			t.Errorf("#%d: Incorrect error result (did pass? %v, expected: %v)", i, err == nil, test.ok)
+		}
+		if err == nil && !reflect.DeepEqual(test.out, tagAndLength) {
+			t.Errorf("#%d: Bad result: %v (expected %v)", i, tagAndLength, test.out)
+		}
+	}
+}
+
+type parseFieldParametersTest struct {
+	in  string
+	out fieldParameters
+}
+
+func newInt(n int) *int { return &n }
+
+func newInt64(n int64) *int64 { return &n }
+
+func newString(s string) *string { return &s }
+
+func newBool(b bool) *bool { return &b }
+
+var parseFieldParametersTestData []parseFieldParametersTest = []parseFieldParametersTest{
+	{"", fieldParameters{}},
+	{"ia5", fieldParameters{stringType: tagIA5String}},
+	{"printable", fieldParameters{stringType: tagPrintableString}},
+	{"optional", fieldParameters{optional: true}},
+	{"explicit", fieldParameters{explicit: true, tag: new(int)}},
+	{"application", fieldParameters{application: true, tag: new(int)}},
+	{"optional,explicit", fieldParameters{optional: true, explicit: true, tag: new(int)}},
+	{"default:42", fieldParameters{defaultValue: newInt64(42)}},
+	{"tag:17", fieldParameters{tag: newInt(17)}},
+	{"optional,explicit,default:42,tag:17", fieldParameters{optional: true, explicit: true, defaultValue: newInt64(42), tag: newInt(17)}},
+	{"optional,explicit,default:42,tag:17,rubbish1", fieldParameters{true, true, false, newInt64(42), newInt(17), 0, false}},
+	{"set", fieldParameters{set: true}},
+}
+
+func TestParseFieldParameters(t *testing.T) {
+	for i, test := range parseFieldParametersTestData {
+		f := parseFieldParameters(test.in)
+		if !reflect.DeepEqual(f, test.out) {
+			t.Errorf("#%d: Bad result: %v (expected %v)", i, f, test.out)
+		}
+	}
+}
+
+type TestObjectIdentifierStruct struct {
+	OID ObjectIdentifier
+}
+
+type TestContextSpecificTags struct {
+	A int `asn1:"tag:1"`
+}
+
+type TestContextSpecificTags2 struct {
+	A int `asn1:"explicit,tag:1"`
+	B int
+}
+
+type TestElementsAfterString struct {
+	S    string
+	A, B int
+}
+
+var unmarshalTestData = []struct {
+	in  []byte
+	out interface{}
+}{
+	{[]byte{0x02, 0x01, 0x42}, newInt(0x42)},
+	{[]byte{0x30, 0x08, 0x06, 0x06, 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d}, &TestObjectIdentifierStruct{[]int{1, 2, 840, 113549}}},
+	{[]byte{0x03, 0x04, 0x06, 0x6e, 0x5d, 0xc0}, &BitString{[]byte{110, 93, 192}, 18}},
+	{[]byte{0x30, 0x09, 0x02, 0x01, 0x01, 0x02, 0x01, 0x02, 0x02, 0x01, 0x03}, &[]int{1, 2, 3}},
+	{[]byte{0x02, 0x01, 0x10}, newInt(16)},
+	{[]byte{0x13, 0x04, 't', 'e', 's', 't'}, newString("test")},
+	{[]byte{0x16, 0x04, 't', 'e', 's', 't'}, newString("test")},
+	{[]byte{0x16, 0x04, 't', 'e', 's', 't'}, &RawValue{0, 22, false, []byte("test"), []byte("\x16\x04test")}},
+	{[]byte{0x04, 0x04, 1, 2, 3, 4}, &RawValue{0, 4, false, []byte{1, 2, 3, 4}, []byte{4, 4, 1, 2, 3, 4}}},
+	{[]byte{0x30, 0x03, 0x81, 0x01, 0x01}, &TestContextSpecificTags{1}},
+	{[]byte{0x30, 0x08, 0xa1, 0x03, 0x02, 0x01, 0x01, 0x02, 0x01, 0x02}, &TestContextSpecificTags2{1, 2}},
+	{[]byte{0x01, 0x01, 0x00}, newBool(false)},
+	{[]byte{0x01, 0x01, 0x01}, newBool(true)},
+	{[]byte{0x30, 0x0b, 0x13, 0x03, 0x66, 0x6f, 0x6f, 0x02, 0x01, 0x22, 0x02, 0x01, 0x33}, &TestElementsAfterString{"foo", 0x22, 0x33}},
+}
+
+func TestUnmarshal(t *testing.T) {
+	for i, test := range unmarshalTestData {
+		pv := reflect.New(reflect.TypeOf(test.out).Elem())
+		val := pv.Interface()
+		_, err := Unmarshal(test.in, val)
+		if err != nil {
+			t.Errorf("Unmarshal failed at index %d %v", i, err)
+		}
+		if !reflect.DeepEqual(val, test.out) {
+			t.Errorf("#%d:\nhave %#v\nwant %#v", i, val, test.out)
+		}
+	}
+}
+
+type Certificate struct {
+	TBSCertificate     TBSCertificate
+	SignatureAlgorithm AlgorithmIdentifier
+	SignatureValue     BitString
+}
+
+type TBSCertificate struct {
+	Version            int `asn1:"optional,explicit,default:0,tag:0"`
+	SerialNumber       RawValue
+	SignatureAlgorithm AlgorithmIdentifier
+	Issuer             RDNSequence
+	Validity           Validity
+	Subject            RDNSequence
+	PublicKey          PublicKeyInfo
+}
+
+type AlgorithmIdentifier struct {
+	Algorithm ObjectIdentifier
+}
+
+type RDNSequence []RelativeDistinguishedNameSET
+
+type RelativeDistinguishedNameSET []AttributeTypeAndValue
+
+type AttributeTypeAndValue struct {
+	Type  ObjectIdentifier
+	Value interface{}
+}
+
+type Validity struct {
+	NotBefore, NotAfter *time.Time
+}
+
+type PublicKeyInfo struct {
+	Algorithm AlgorithmIdentifier
+	PublicKey BitString
+}
+
+func TestCertificate(t *testing.T) {
+	// This is a minimal, self-signed certificate that should parse correctly.
+	var cert Certificate
+	if _, err := Unmarshal(derEncodedSelfSignedCertBytes, &cert); err != nil {
+		t.Errorf("Unmarshal failed: %v", err)
+	}
+	if !reflect.DeepEqual(cert, derEncodedSelfSignedCert) {
+		t.Errorf("Bad result:\ngot: %+v\nwant: %+v", cert, derEncodedSelfSignedCert)
+	}
+}
+
+func TestCertificateWithNUL(t *testing.T) {
+	// This is the paypal NUL-hack certificate. It should fail to parse because
+	// NUL isn't a permitted character in a PrintableString.
+
+	var cert Certificate
+	if _, err := Unmarshal(derEncodedPaypalNULCertBytes, &cert); err == nil {
+		t.Error("Unmarshal succeeded, should not have")
+	}
+}
+
+type rawStructTest struct {
+	Raw RawContent
+	A   int
+}
+
+func TestRawStructs(t *testing.T) {
+	var s rawStructTest
+	input := []byte{0x30, 0x03, 0x02, 0x01, 0x50}
+
+	rest, err := Unmarshal(input, &s)
+	if len(rest) != 0 {
+		t.Errorf("incomplete parse: %x", rest)
+		return
+	}
+	if err != nil {
+		t.Error(err)
+		return
+	}
+	if s.A != 0x50 {
+		t.Errorf("bad value for A: got %d want %d", s.A, 0x50)
+	}
+	if bytes.Compare([]byte(s.Raw), input) != 0 {
+		t.Errorf("bad value for Raw: got %x want %x", s.Raw, input)
+	}
+}
+
+var derEncodedSelfSignedCert = Certificate{
+	TBSCertificate: TBSCertificate{
+		Version:            0,
+		SerialNumber:       RawValue{Class: 0, Tag: 2, IsCompound: false, Bytes: []uint8{0x0, 0x8c, 0xc3, 0x37, 0x92, 0x10, 0xec, 0x2c, 0x98}, FullBytes: []byte{2, 9, 0x0, 0x8c, 0xc3, 0x37, 0x92, 0x10, 0xec, 0x2c, 0x98}},
+		SignatureAlgorithm: AlgorithmIdentifier{Algorithm: ObjectIdentifier{1, 2, 840, 113549, 1, 1, 5}},
+		Issuer: RDNSequence{
+			RelativeDistinguishedNameSET{AttributeTypeAndValue{Type: ObjectIdentifier{2, 5, 4, 6}, Value: "XX"}},
+			RelativeDistinguishedNameSET{AttributeTypeAndValue{Type: ObjectIdentifier{2, 5, 4, 8}, Value: "Some-State"}},
+			RelativeDistinguishedNameSET{AttributeTypeAndValue{Type: ObjectIdentifier{2, 5, 4, 7}, Value: "City"}},
+			RelativeDistinguishedNameSET{AttributeTypeAndValue{Type: ObjectIdentifier{2, 5, 4, 10}, Value: "Internet Widgits Pty Ltd"}},
+			RelativeDistinguishedNameSET{AttributeTypeAndValue{Type: ObjectIdentifier{2, 5, 4, 3}, Value: "false.example.com"}},
+			RelativeDistinguishedNameSET{AttributeTypeAndValue{Type: ObjectIdentifier{1, 2, 840, 113549, 1, 9, 1}, Value: "false@example.com"}},
+		},
+		Validity: Validity{NotBefore: &time.Time{Year: 2009, Month: 10, Day: 8, Hour: 0, Minute: 25, Second: 53, ZoneOffset: 0, Zone: "UTC"}, NotAfter: &time.Time{Year: 2010, Month: 10, Day: 8, Hour: 0, Minute: 25, Second: 53, ZoneOffset: 0, Zone: "UTC"}},
+		Subject: RDNSequence{
+			RelativeDistinguishedNameSET{AttributeTypeAndValue{Type: ObjectIdentifier{2, 5, 4, 6}, Value: "XX"}},
+			RelativeDistinguishedNameSET{AttributeTypeAndValue{Type: ObjectIdentifier{2, 5, 4, 8}, Value: "Some-State"}},
+			RelativeDistinguishedNameSET{AttributeTypeAndValue{Type: ObjectIdentifier{2, 5, 4, 7}, Value: "City"}},
+			RelativeDistinguishedNameSET{AttributeTypeAndValue{Type: ObjectIdentifier{2, 5, 4, 10}, Value: "Internet Widgits Pty Ltd"}},
+			RelativeDistinguishedNameSET{AttributeTypeAndValue{Type: ObjectIdentifier{2, 5, 4, 3}, Value: "false.example.com"}},
+			RelativeDistinguishedNameSET{AttributeTypeAndValue{Type: ObjectIdentifier{1, 2, 840, 113549, 1, 9, 1}, Value: "false@example.com"}},
+		},
+		PublicKey: PublicKeyInfo{
+			Algorithm: AlgorithmIdentifier{Algorithm: ObjectIdentifier{1, 2, 840, 113549, 1, 1, 1}},
+			PublicKey: BitString{
+				Bytes: []uint8{
+					0x30, 0x48, 0x2, 0x41, 0x0, 0xcd, 0xb7,
+					0x63, 0x9c, 0x32, 0x78, 0xf0, 0x6, 0xaa, 0x27, 0x7f, 0x6e, 0xaf, 0x42,
+					0x90, 0x2b, 0x59, 0x2d, 0x8c, 0xbc, 0xbe, 0x38, 0xa1, 0xc9, 0x2b, 0xa4,
+					0x69, 0x5a, 0x33, 0x1b, 0x1d, 0xea, 0xde, 0xad, 0xd8, 0xe9, 0xa5, 0xc2,
+					0x7e, 0x8c, 0x4c, 0x2f, 0xd0, 0xa8, 0x88, 0x96, 0x57, 0x72, 0x2a, 0x4f,
+					0x2a, 0xf7, 0x58, 0x9c, 0xf2, 0xc7, 0x70, 0x45, 0xdc, 0x8f, 0xde, 0xec,
+					0x35, 0x7d, 0x2, 0x3, 0x1, 0x0, 0x1,
+				},
+				BitLength: 592,
+			},
+		},
+	},
+	SignatureAlgorithm: AlgorithmIdentifier{Algorithm: ObjectIdentifier{1, 2, 840, 113549, 1, 1, 5}},
+	SignatureValue: BitString{
+		Bytes: []uint8{
+			0xa6, 0x7b, 0x6, 0xec, 0x5e, 0xce,
+			0x92, 0x77, 0x2c, 0xa4, 0x13, 0xcb, 0xa3, 0xca, 0x12, 0x56, 0x8f, 0xdc, 0x6c,
+			0x7b, 0x45, 0x11, 0xcd, 0x40, 0xa7, 0xf6, 0x59, 0x98, 0x4, 0x2, 0xdf, 0x2b,
+			0x99, 0x8b, 0xb9, 0xa4, 0xa8, 0xcb, 0xeb, 0x34, 0xc0, 0xf0, 0xa7, 0x8c, 0xf8,
+			0xd9, 0x1e, 0xde, 0x14, 0xa5, 0xed, 0x76, 0xbf, 0x11, 0x6f, 0xe3, 0x60, 0xaa,
+			0xfa, 0x88, 0x21, 0x49, 0x4, 0x35,
+		},
+		BitLength: 512,
+	},
+}
+
+var derEncodedSelfSignedCertBytes = []byte{
+	0x30, 0x82, 0x02, 0x18, 0x30,
+	0x82, 0x01, 0xc2, 0x02, 0x09, 0x00, 0x8c, 0xc3, 0x37, 0x92, 0x10, 0xec, 0x2c,
+	0x98, 0x30, 0x0d, 0x06, 0x09, 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x01,
+	0x05, 0x05, 0x00, 0x30, 0x81, 0x92, 0x31, 0x0b, 0x30, 0x09, 0x06, 0x03, 0x55,
+	0x04, 0x06, 0x13, 0x02, 0x58, 0x58, 0x31, 0x13, 0x30, 0x11, 0x06, 0x03, 0x55,
+	0x04, 0x08, 0x13, 0x0a, 0x53, 0x6f, 0x6d, 0x65, 0x2d, 0x53, 0x74, 0x61, 0x74,
+	0x65, 0x31, 0x0d, 0x30, 0x0b, 0x06, 0x03, 0x55, 0x04, 0x07, 0x13, 0x04, 0x43,
+	0x69, 0x74, 0x79, 0x31, 0x21, 0x30, 0x1f, 0x06, 0x03, 0x55, 0x04, 0x0a, 0x13,
+	0x18, 0x49, 0x6e, 0x74, 0x65, 0x72, 0x6e, 0x65, 0x74, 0x20, 0x57, 0x69, 0x64,
+	0x67, 0x69, 0x74, 0x73, 0x20, 0x50, 0x74, 0x79, 0x20, 0x4c, 0x74, 0x64, 0x31,
+	0x1a, 0x30, 0x18, 0x06, 0x03, 0x55, 0x04, 0x03, 0x13, 0x11, 0x66, 0x61, 0x6c,
+	0x73, 0x65, 0x2e, 0x65, 0x78, 0x61, 0x6d, 0x70, 0x6c, 0x65, 0x2e, 0x63, 0x6f,
+	0x6d, 0x31, 0x20, 0x30, 0x1e, 0x06, 0x09, 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d,
+	0x01, 0x09, 0x01, 0x16, 0x11, 0x66, 0x61, 0x6c, 0x73, 0x65, 0x40, 0x65, 0x78,
+	0x61, 0x6d, 0x70, 0x6c, 0x65, 0x2e, 0x63, 0x6f, 0x6d, 0x30, 0x1e, 0x17, 0x0d,
+	0x30, 0x39, 0x31, 0x30, 0x30, 0x38, 0x30, 0x30, 0x32, 0x35, 0x35, 0x33, 0x5a,
+	0x17, 0x0d, 0x31, 0x30, 0x31, 0x30, 0x30, 0x38, 0x30, 0x30, 0x32, 0x35, 0x35,
+	0x33, 0x5a, 0x30, 0x81, 0x92, 0x31, 0x0b, 0x30, 0x09, 0x06, 0x03, 0x55, 0x04,
+	0x06, 0x13, 0x02, 0x58, 0x58, 0x31, 0x13, 0x30, 0x11, 0x06, 0x03, 0x55, 0x04,
+	0x08, 0x13, 0x0a, 0x53, 0x6f, 0x6d, 0x65, 0x2d, 0x53, 0x74, 0x61, 0x74, 0x65,
+	0x31, 0x0d, 0x30, 0x0b, 0x06, 0x03, 0x55, 0x04, 0x07, 0x13, 0x04, 0x43, 0x69,
+	0x74, 0x79, 0x31, 0x21, 0x30, 0x1f, 0x06, 0x03, 0x55, 0x04, 0x0a, 0x13, 0x18,
+	0x49, 0x6e, 0x74, 0x65, 0x72, 0x6e, 0x65, 0x74, 0x20, 0x57, 0x69, 0x64, 0x67,
+	0x69, 0x74, 0x73, 0x20, 0x50, 0x74, 0x79, 0x20, 0x4c, 0x74, 0x64, 0x31, 0x1a,
+	0x30, 0x18, 0x06, 0x03, 0x55, 0x04, 0x03, 0x13, 0x11, 0x66, 0x61, 0x6c, 0x73,
+	0x65, 0x2e, 0x65, 0x78, 0x61, 0x6d, 0x70, 0x6c, 0x65, 0x2e, 0x63, 0x6f, 0x6d,
+	0x31, 0x20, 0x30, 0x1e, 0x06, 0x09, 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01,
+	0x09, 0x01, 0x16, 0x11, 0x66, 0x61, 0x6c, 0x73, 0x65, 0x40, 0x65, 0x78, 0x61,
+	0x6d, 0x70, 0x6c, 0x65, 0x2e, 0x63, 0x6f, 0x6d, 0x30, 0x5c, 0x30, 0x0d, 0x06,
+	0x09, 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x01, 0x01, 0x05, 0x00, 0x03,
+	0x4b, 0x00, 0x30, 0x48, 0x02, 0x41, 0x00, 0xcd, 0xb7, 0x63, 0x9c, 0x32, 0x78,
+	0xf0, 0x06, 0xaa, 0x27, 0x7f, 0x6e, 0xaf, 0x42, 0x90, 0x2b, 0x59, 0x2d, 0x8c,
+	0xbc, 0xbe, 0x38, 0xa1, 0xc9, 0x2b, 0xa4, 0x69, 0x5a, 0x33, 0x1b, 0x1d, 0xea,
+	0xde, 0xad, 0xd8, 0xe9, 0xa5, 0xc2, 0x7e, 0x8c, 0x4c, 0x2f, 0xd0, 0xa8, 0x88,
+	0x96, 0x57, 0x72, 0x2a, 0x4f, 0x2a, 0xf7, 0x58, 0x9c, 0xf2, 0xc7, 0x70, 0x45,
+	0xdc, 0x8f, 0xde, 0xec, 0x35, 0x7d, 0x02, 0x03, 0x01, 0x00, 0x01, 0x30, 0x0d,
+	0x06, 0x09, 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x01, 0x05, 0x05, 0x00,
+	0x03, 0x41, 0x00, 0xa6, 0x7b, 0x06, 0xec, 0x5e, 0xce, 0x92, 0x77, 0x2c, 0xa4,
+	0x13, 0xcb, 0xa3, 0xca, 0x12, 0x56, 0x8f, 0xdc, 0x6c, 0x7b, 0x45, 0x11, 0xcd,
+	0x40, 0xa7, 0xf6, 0x59, 0x98, 0x04, 0x02, 0xdf, 0x2b, 0x99, 0x8b, 0xb9, 0xa4,
+	0xa8, 0xcb, 0xeb, 0x34, 0xc0, 0xf0, 0xa7, 0x8c, 0xf8, 0xd9, 0x1e, 0xde, 0x14,
+	0xa5, 0xed, 0x76, 0xbf, 0x11, 0x6f, 0xe3, 0x60, 0xaa, 0xfa, 0x88, 0x21, 0x49,
+	0x04, 0x35,
+}
+
+var derEncodedPaypalNULCertBytes = []byte{
+	0x30, 0x82, 0x06, 0x44, 0x30,
+	0x82, 0x05, 0xad, 0xa0, 0x03, 0x02, 0x01, 0x02, 0x02, 0x03, 0x00, 0xf0, 0x9b,
+	0x30, 0x0d, 0x06, 0x09, 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x01, 0x05,
+	0x05, 0x00, 0x30, 0x82, 0x01, 0x12, 0x31, 0x0b, 0x30, 0x09, 0x06, 0x03, 0x55,
+	0x04, 0x06, 0x13, 0x02, 0x45, 0x53, 0x31, 0x12, 0x30, 0x10, 0x06, 0x03, 0x55,
+	0x04, 0x08, 0x13, 0x09, 0x42, 0x61, 0x72, 0x63, 0x65, 0x6c, 0x6f, 0x6e, 0x61,
+	0x31, 0x12, 0x30, 0x10, 0x06, 0x03, 0x55, 0x04, 0x07, 0x13, 0x09, 0x42, 0x61,
+	0x72, 0x63, 0x65, 0x6c, 0x6f, 0x6e, 0x61, 0x31, 0x29, 0x30, 0x27, 0x06, 0x03,
+	0x55, 0x04, 0x0a, 0x13, 0x20, 0x49, 0x50, 0x53, 0x20, 0x43, 0x65, 0x72, 0x74,
+	0x69, 0x66, 0x69, 0x63, 0x61, 0x74, 0x69, 0x6f, 0x6e, 0x20, 0x41, 0x75, 0x74,
+	0x68, 0x6f, 0x72, 0x69, 0x74, 0x79, 0x20, 0x73, 0x2e, 0x6c, 0x2e, 0x31, 0x2e,
+	0x30, 0x2c, 0x06, 0x03, 0x55, 0x04, 0x0a, 0x14, 0x25, 0x67, 0x65, 0x6e, 0x65,
+	0x72, 0x61, 0x6c, 0x40, 0x69, 0x70, 0x73, 0x63, 0x61, 0x2e, 0x63, 0x6f, 0x6d,
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+	0x32, 0x32, 0x31, 0x30, 0x36, 0x39, 0x35, 0x31, 0x2e, 0x30, 0x2c, 0x06, 0x03,
+	0x55, 0x04, 0x0b, 0x13, 0x25, 0x69, 0x70, 0x73, 0x43, 0x41, 0x20, 0x43, 0x4c,
+	0x41, 0x53, 0x45, 0x41, 0x31, 0x20, 0x43, 0x65, 0x72, 0x74, 0x69, 0x66, 0x69,
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+	0xfa, 0x6f, 0x3a, 0x00, 0xb4, 0x21, 0x1b, 0xc8, 0xb1, 0x02, 0xd7, 0x3f, 0x19,
+	0xb2, 0xc4, 0x6d, 0xb4, 0x54, 0xf8, 0x8b, 0x8a, 0xcc, 0xdb, 0x72, 0xc2, 0x9e,
+	0x3c, 0x60, 0xb9, 0xc6, 0x91, 0x3d, 0x82, 0xb7, 0x7d, 0x99, 0xff, 0xd1, 0x29,
+	0x84, 0xc1, 0x73, 0x53, 0x9c, 0x82, 0xdd, 0xfc, 0x24, 0x8c, 0x77, 0xd5, 0x41,
+	0xf3, 0xe8, 0x1e, 0x42, 0xa1, 0xad, 0x2d, 0x9e, 0xff, 0x5b, 0x10, 0x26, 0xce,
+	0x9d, 0x57, 0x17, 0x73, 0x16, 0x23, 0x38, 0xc8, 0xd6, 0xf1, 0xba, 0xa3, 0x96,
+	0x5b, 0x16, 0x67, 0x4a, 0x4f, 0x73, 0x97, 0x3a, 0x4d, 0x14, 0xa4, 0xf4, 0xe2,
+	0x3f, 0x8b, 0x05, 0x83, 0x42, 0xd1, 0xd0, 0xdc, 0x2f, 0x7a, 0xe5, 0xb6, 0x10,
+	0xb2, 0x11, 0xc0, 0xdc, 0x21, 0x2a, 0x90, 0xff, 0xae, 0x97, 0x71, 0x5a, 0x49,
+	0x81, 0xac, 0x40, 0xf3, 0x3b, 0xb8, 0x59, 0xb2, 0x4f, 0x02, 0x03, 0x01, 0x00,
+	0x01, 0xa3, 0x82, 0x03, 0x21, 0x30, 0x82, 0x03, 0x1d, 0x30, 0x09, 0x06, 0x03,
+	0x55, 0x1d, 0x13, 0x04, 0x02, 0x30, 0x00, 0x30, 0x11, 0x06, 0x09, 0x60, 0x86,
+	0x48, 0x01, 0x86, 0xf8, 0x42, 0x01, 0x01, 0x04, 0x04, 0x03, 0x02, 0x06, 0x40,
+	0x30, 0x0b, 0x06, 0x03, 0x55, 0x1d, 0x0f, 0x04, 0x04, 0x03, 0x02, 0x03, 0xf8,
+	0x30, 0x13, 0x06, 0x03, 0x55, 0x1d, 0x25, 0x04, 0x0c, 0x30, 0x0a, 0x06, 0x08,
+	0x2b, 0x06, 0x01, 0x05, 0x05, 0x07, 0x03, 0x01, 0x30, 0x1d, 0x06, 0x03, 0x55,
+	0x1d, 0x0e, 0x04, 0x16, 0x04, 0x14, 0x61, 0x8f, 0x61, 0x34, 0x43, 0x55, 0x14,
+	0x7f, 0x27, 0x09, 0xce, 0x4c, 0x8b, 0xea, 0x9b, 0x7b, 0x19, 0x25, 0xbc, 0x6e,
+	0x30, 0x1f, 0x06, 0x03, 0x55, 0x1d, 0x23, 0x04, 0x18, 0x30, 0x16, 0x80, 0x14,
+	0x0e, 0x07, 0x60, 0xd4, 0x39, 0xc9, 0x1b, 0x5b, 0x5d, 0x90, 0x7b, 0x23, 0xc8,
+	0xd2, 0x34, 0x9d, 0x4a, 0x9a, 0x46, 0x39, 0x30, 0x09, 0x06, 0x03, 0x55, 0x1d,
+	0x11, 0x04, 0x02, 0x30, 0x00, 0x30, 0x1c, 0x06, 0x03, 0x55, 0x1d, 0x12, 0x04,
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+	0x69, 0x70, 0x73, 0x63, 0x61, 0x2e, 0x63, 0x6f, 0x6d, 0x30, 0x72, 0x06, 0x09,
+	0x60, 0x86, 0x48, 0x01, 0x86, 0xf8, 0x42, 0x01, 0x0d, 0x04, 0x65, 0x16, 0x63,
+	0x4f, 0x72, 0x67, 0x61, 0x6e, 0x69, 0x7a, 0x61, 0x74, 0x69, 0x6f, 0x6e, 0x20,
+	0x49, 0x6e, 0x66, 0x6f, 0x72, 0x6d, 0x61, 0x74, 0x69, 0x6f, 0x6e, 0x20, 0x4e,
+	0x4f, 0x54, 0x20, 0x56, 0x41, 0x4c, 0x49, 0x44, 0x41, 0x54, 0x45, 0x44, 0x2e,
+	0x20, 0x43, 0x4c, 0x41, 0x53, 0x45, 0x41, 0x31, 0x20, 0x53, 0x65, 0x72, 0x76,
+	0x65, 0x72, 0x20, 0x43, 0x65, 0x72, 0x74, 0x69, 0x66, 0x69, 0x63, 0x61, 0x74,
+	0x65, 0x20, 0x69, 0x73, 0x73, 0x75, 0x65, 0x64, 0x20, 0x62, 0x79, 0x20, 0x68,
+	0x74, 0x74, 0x70, 0x73, 0x3a, 0x2f, 0x2f, 0x77, 0x77, 0x77, 0x2e, 0x69, 0x70,
+	0x73, 0x63, 0x61, 0x2e, 0x63, 0x6f, 0x6d, 0x2f, 0x30, 0x2f, 0x06, 0x09, 0x60,
+	0x86, 0x48, 0x01, 0x86, 0xf8, 0x42, 0x01, 0x02, 0x04, 0x22, 0x16, 0x20, 0x68,
+	0x74, 0x74, 0x70, 0x73, 0x3a, 0x2f, 0x2f, 0x77, 0x77, 0x77, 0x2e, 0x69, 0x70,
+	0x73, 0x63, 0x61, 0x2e, 0x63, 0x6f, 0x6d, 0x2f, 0x69, 0x70, 0x73, 0x63, 0x61,
+	0x32, 0x30, 0x30, 0x32, 0x2f, 0x30, 0x43, 0x06, 0x09, 0x60, 0x86, 0x48, 0x01,
+	0x86, 0xf8, 0x42, 0x01, 0x04, 0x04, 0x36, 0x16, 0x34, 0x68, 0x74, 0x74, 0x70,
+	0x73, 0x3a, 0x2f, 0x2f, 0x77, 0x77, 0x77, 0x2e, 0x69, 0x70, 0x73, 0x63, 0x61,
+	0x2e, 0x63, 0x6f, 0x6d, 0x2f, 0x69, 0x70, 0x73, 0x63, 0x61, 0x32, 0x30, 0x30,
+	0x32, 0x2f, 0x69, 0x70, 0x73, 0x63, 0x61, 0x32, 0x30, 0x30, 0x32, 0x43, 0x4c,
+	0x41, 0x53, 0x45, 0x41, 0x31, 0x2e, 0x63, 0x72, 0x6c, 0x30, 0x46, 0x06, 0x09,
+	0x60, 0x86, 0x48, 0x01, 0x86, 0xf8, 0x42, 0x01, 0x03, 0x04, 0x39, 0x16, 0x37,
+	0x68, 0x74, 0x74, 0x70, 0x73, 0x3a, 0x2f, 0x2f, 0x77, 0x77, 0x77, 0x2e, 0x69,
+	0x70, 0x73, 0x63, 0x61, 0x2e, 0x63, 0x6f, 0x6d, 0x2f, 0x69, 0x70, 0x73, 0x63,
+	0x61, 0x32, 0x30, 0x30, 0x32, 0x2f, 0x72, 0x65, 0x76, 0x6f, 0x63, 0x61, 0x74,
+	0x69, 0x6f, 0x6e, 0x43, 0x4c, 0x41, 0x53, 0x45, 0x41, 0x31, 0x2e, 0x68, 0x74,
+	0x6d, 0x6c, 0x3f, 0x30, 0x43, 0x06, 0x09, 0x60, 0x86, 0x48, 0x01, 0x86, 0xf8,
+	0x42, 0x01, 0x07, 0x04, 0x36, 0x16, 0x34, 0x68, 0x74, 0x74, 0x70, 0x73, 0x3a,
+	0x2f, 0x2f, 0x77, 0x77, 0x77, 0x2e, 0x69, 0x70, 0x73, 0x63, 0x61, 0x2e, 0x63,
+	0x6f, 0x6d, 0x2f, 0x69, 0x70, 0x73, 0x63, 0x61, 0x32, 0x30, 0x30, 0x32, 0x2f,
+	0x72, 0x65, 0x6e, 0x65, 0x77, 0x61, 0x6c, 0x43, 0x4c, 0x41, 0x53, 0x45, 0x41,
+	0x31, 0x2e, 0x68, 0x74, 0x6d, 0x6c, 0x3f, 0x30, 0x41, 0x06, 0x09, 0x60, 0x86,
+	0x48, 0x01, 0x86, 0xf8, 0x42, 0x01, 0x08, 0x04, 0x34, 0x16, 0x32, 0x68, 0x74,
+	0x74, 0x70, 0x73, 0x3a, 0x2f, 0x2f, 0x77, 0x77, 0x77, 0x2e, 0x69, 0x70, 0x73,
+	0x63, 0x61, 0x2e, 0x63, 0x6f, 0x6d, 0x2f, 0x69, 0x70, 0x73, 0x63, 0x61, 0x32,
+	0x30, 0x30, 0x32, 0x2f, 0x70, 0x6f, 0x6c, 0x69, 0x63, 0x79, 0x43, 0x4c, 0x41,
+	0x53, 0x45, 0x41, 0x31, 0x2e, 0x68, 0x74, 0x6d, 0x6c, 0x30, 0x81, 0x83, 0x06,
+	0x03, 0x55, 0x1d, 0x1f, 0x04, 0x7c, 0x30, 0x7a, 0x30, 0x39, 0xa0, 0x37, 0xa0,
+	0x35, 0x86, 0x33, 0x68, 0x74, 0x74, 0x70, 0x3a, 0x2f, 0x2f, 0x77, 0x77, 0x77,
+	0x2e, 0x69, 0x70, 0x73, 0x63, 0x61, 0x2e, 0x63, 0x6f, 0x6d, 0x2f, 0x69, 0x70,
+	0x73, 0x63, 0x61, 0x32, 0x30, 0x30, 0x32, 0x2f, 0x69, 0x70, 0x73, 0x63, 0x61,
+	0x32, 0x30, 0x30, 0x32, 0x43, 0x4c, 0x41, 0x53, 0x45, 0x41, 0x31, 0x2e, 0x63,
+	0x72, 0x6c, 0x30, 0x3d, 0xa0, 0x3b, 0xa0, 0x39, 0x86, 0x37, 0x68, 0x74, 0x74,
+	0x70, 0x3a, 0x2f, 0x2f, 0x77, 0x77, 0x77, 0x62, 0x61, 0x63, 0x6b, 0x2e, 0x69,
+	0x70, 0x73, 0x63, 0x61, 0x2e, 0x63, 0x6f, 0x6d, 0x2f, 0x69, 0x70, 0x73, 0x63,
+	0x61, 0x32, 0x30, 0x30, 0x32, 0x2f, 0x69, 0x70, 0x73, 0x63, 0x61, 0x32, 0x30,
+	0x30, 0x32, 0x43, 0x4c, 0x41, 0x53, 0x45, 0x41, 0x31, 0x2e, 0x63, 0x72, 0x6c,
+	0x30, 0x32, 0x06, 0x08, 0x2b, 0x06, 0x01, 0x05, 0x05, 0x07, 0x01, 0x01, 0x04,
+	0x26, 0x30, 0x24, 0x30, 0x22, 0x06, 0x08, 0x2b, 0x06, 0x01, 0x05, 0x05, 0x07,
+	0x30, 0x01, 0x86, 0x16, 0x68, 0x74, 0x74, 0x70, 0x3a, 0x2f, 0x2f, 0x6f, 0x63,
+	0x73, 0x70, 0x2e, 0x69, 0x70, 0x73, 0x63, 0x61, 0x2e, 0x63, 0x6f, 0x6d, 0x2f,
+	0x30, 0x0d, 0x06, 0x09, 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x01, 0x05,
+	0x05, 0x00, 0x03, 0x81, 0x81, 0x00, 0x68, 0xee, 0x79, 0x97, 0x97, 0xdd, 0x3b,
+	0xef, 0x16, 0x6a, 0x06, 0xf2, 0x14, 0x9a, 0x6e, 0xcd, 0x9e, 0x12, 0xf7, 0xaa,
+	0x83, 0x10, 0xbd, 0xd1, 0x7c, 0x98, 0xfa, 0xc7, 0xae, 0xd4, 0x0e, 0x2c, 0x9e,
+	0x38, 0x05, 0x9d, 0x52, 0x60, 0xa9, 0x99, 0x0a, 0x81, 0xb4, 0x98, 0x90, 0x1d,
+	0xae, 0xbb, 0x4a, 0xd7, 0xb9, 0xdc, 0x88, 0x9e, 0x37, 0x78, 0x41, 0x5b, 0xf7,
+	0x82, 0xa5, 0xf2, 0xba, 0x41, 0x25, 0x5a, 0x90, 0x1a, 0x1e, 0x45, 0x38, 0xa1,
+	0x52, 0x58, 0x75, 0x94, 0x26, 0x44, 0xfb, 0x20, 0x07, 0xba, 0x44, 0xcc, 0xe5,
+	0x4a, 0x2d, 0x72, 0x3f, 0x98, 0x47, 0xf6, 0x26, 0xdc, 0x05, 0x46, 0x05, 0x07,
+	0x63, 0x21, 0xab, 0x46, 0x9b, 0x9c, 0x78, 0xd5, 0x54, 0x5b, 0x3d, 0x0c, 0x1e,
+	0xc8, 0x64, 0x8c, 0xb5, 0x50, 0x23, 0x82, 0x6f, 0xdb, 0xb8, 0x22, 0x1c, 0x43,
+	0x96, 0x07, 0xa8, 0xbb,
+}
diff --git a/libgo/go/encoding/asn1/common.go b/libgo/go/encoding/asn1/common.go
new file mode 100644
index 00000000000..01f4f7b6ec7
--- /dev/null
+++ b/libgo/go/encoding/asn1/common.go
@@ -0,0 +1,158 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package asn1
+
+import (
+	"reflect"
+	"strconv"
+	"strings"
+)
+
+// ASN.1 objects have metadata preceding them:
+//   the tag: the type of the object
+//   a flag denoting if this object is compound or not
+//   the class type: the namespace of the tag
+//   the length of the object, in bytes
+
+// Here are some standard tags and classes
+
+const (
+	tagBoolean         = 1
+	tagInteger         = 2
+	tagBitString       = 3
+	tagOctetString     = 4
+	tagOID             = 6
+	tagEnum            = 10
+	tagUTF8String      = 12
+	tagSequence        = 16
+	tagSet             = 17
+	tagPrintableString = 19
+	tagT61String       = 20
+	tagIA5String       = 22
+	tagUTCTime         = 23
+	tagGeneralizedTime = 24
+	tagGeneralString   = 27
+)
+
+const (
+	classUniversal       = 0
+	classApplication     = 1
+	classContextSpecific = 2
+	classPrivate         = 3
+)
+
+type tagAndLength struct {
+	class, tag, length int
+	isCompound         bool
+}
+
+// ASN.1 has IMPLICIT and EXPLICIT tags, which can be translated as "instead
+// of" and "in addition to". When not specified, every primitive type has a
+// default tag in the UNIVERSAL class.
+//
+// For example: a BIT STRING is tagged [UNIVERSAL 3] by default (although ASN.1
+// doesn't actually have a UNIVERSAL keyword). However, by saying [IMPLICIT
+// CONTEXT-SPECIFIC 42], that means that the tag is replaced by another.
+//
+// On the other hand, if it said [EXPLICIT CONTEXT-SPECIFIC 10], then an
+// /additional/ tag would wrap the default tag. This explicit tag will have the
+// compound flag set.
+//
+// (This is used in order to remove ambiguity with optional elements.)
+//
+// You can layer EXPLICIT and IMPLICIT tags to an arbitrary depth, however we
+// don't support that here. We support a single layer of EXPLICIT or IMPLICIT
+// tagging with tag strings on the fields of a structure.
+
+// fieldParameters is the parsed representation of tag string from a structure field.
+type fieldParameters struct {
+	optional     bool   // true iff the field is OPTIONAL
+	explicit     bool   // true iff an EXPLICIT tag is in use.
+	application  bool   // true iff an APPLICATION tag is in use.
+	defaultValue *int64 // a default value for INTEGER typed fields (maybe nil).
+	tag          *int   // the EXPLICIT or IMPLICIT tag (maybe nil).
+	stringType   int    // the string tag to use when marshaling.
+	set          bool   // true iff this should be encoded as a SET
+
+	// Invariants:
+	//   if explicit is set, tag is non-nil.
+}
+
+// Given a tag string with the format specified in the package comment,
+// parseFieldParameters will parse it into a fieldParameters structure,
+// ignoring unknown parts of the string.
+func parseFieldParameters(str string) (ret fieldParameters) {
+	for _, part := range strings.Split(str, ",") {
+		switch {
+		case part == "optional":
+			ret.optional = true
+		case part == "explicit":
+			ret.explicit = true
+			if ret.tag == nil {
+				ret.tag = new(int)
+			}
+		case part == "ia5":
+			ret.stringType = tagIA5String
+		case part == "printable":
+			ret.stringType = tagPrintableString
+		case strings.HasPrefix(part, "default:"):
+			i, err := strconv.Atoi64(part[8:])
+			if err == nil {
+				ret.defaultValue = new(int64)
+				*ret.defaultValue = i
+			}
+		case strings.HasPrefix(part, "tag:"):
+			i, err := strconv.Atoi(part[4:])
+			if err == nil {
+				ret.tag = new(int)
+				*ret.tag = i
+			}
+		case part == "set":
+			ret.set = true
+		case part == "application":
+			ret.application = true
+			if ret.tag == nil {
+				ret.tag = new(int)
+			}
+		}
+	}
+	return
+}
+
+// Given a reflected Go type, getUniversalType returns the default tag number
+// and expected compound flag.
+func getUniversalType(t reflect.Type) (tagNumber int, isCompound, ok bool) {
+	switch t {
+	case objectIdentifierType:
+		return tagOID, false, true
+	case bitStringType:
+		return tagBitString, false, true
+	case timeType:
+		return tagUTCTime, false, true
+	case enumeratedType:
+		return tagEnum, false, true
+	case bigIntType:
+		return tagInteger, false, true
+	}
+	switch t.Kind() {
+	case reflect.Bool:
+		return tagBoolean, false, true
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		return tagInteger, false, true
+	case reflect.Struct:
+		return tagSequence, true, true
+	case reflect.Slice:
+		if t.Elem().Kind() == reflect.Uint8 {
+			return tagOctetString, false, true
+		}
+		if strings.HasSuffix(t.Name(), "SET") {
+			return tagSet, true, true
+		}
+		return tagSequence, true, true
+	case reflect.String:
+		return tagPrintableString, false, true
+	}
+	return 0, false, false
+}
diff --git a/libgo/go/encoding/asn1/marshal.go b/libgo/go/encoding/asn1/marshal.go
new file mode 100644
index 00000000000..89c50a70ef4
--- /dev/null
+++ b/libgo/go/encoding/asn1/marshal.go
@@ -0,0 +1,547 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package asn1
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"math/big"
+	"reflect"
+	"time"
+)
+
+// A forkableWriter is an in-memory buffer that can be
+// 'forked' to create new forkableWriters that bracket the
+// original.  After
+//    pre, post := w.fork();
+// the overall sequence of bytes represented is logically w+pre+post.
+type forkableWriter struct {
+	*bytes.Buffer
+	pre, post *forkableWriter
+}
+
+func newForkableWriter() *forkableWriter {
+	return &forkableWriter{bytes.NewBuffer(nil), nil, nil}
+}
+
+func (f *forkableWriter) fork() (pre, post *forkableWriter) {
+	if f.pre != nil || f.post != nil {
+		panic("have already forked")
+	}
+	f.pre = newForkableWriter()
+	f.post = newForkableWriter()
+	return f.pre, f.post
+}
+
+func (f *forkableWriter) Len() (l int) {
+	l += f.Buffer.Len()
+	if f.pre != nil {
+		l += f.pre.Len()
+	}
+	if f.post != nil {
+		l += f.post.Len()
+	}
+	return
+}
+
+func (f *forkableWriter) writeTo(out io.Writer) (n int, err error) {
+	n, err = out.Write(f.Bytes())
+	if err != nil {
+		return
+	}
+
+	var nn int
+
+	if f.pre != nil {
+		nn, err = f.pre.writeTo(out)
+		n += nn
+		if err != nil {
+			return
+		}
+	}
+
+	if f.post != nil {
+		nn, err = f.post.writeTo(out)
+		n += nn
+	}
+	return
+}
+
+func marshalBase128Int(out *forkableWriter, n int64) (err error) {
+	if n == 0 {
+		err = out.WriteByte(0)
+		return
+	}
+
+	l := 0
+	for i := n; i > 0; i >>= 7 {
+		l++
+	}
+
+	for i := l - 1; i >= 0; i-- {
+		o := byte(n >> uint(i*7))
+		o &= 0x7f
+		if i != 0 {
+			o |= 0x80
+		}
+		err = out.WriteByte(o)
+		if err != nil {
+			return
+		}
+	}
+
+	return nil
+}
+
+func marshalInt64(out *forkableWriter, i int64) (err error) {
+	n := int64Length(i)
+
+	for ; n > 0; n-- {
+		err = out.WriteByte(byte(i >> uint((n-1)*8)))
+		if err != nil {
+			return
+		}
+	}
+
+	return nil
+}
+
+func int64Length(i int64) (numBytes int) {
+	numBytes = 1
+
+	for i > 127 {
+		numBytes++
+		i >>= 8
+	}
+
+	for i < -128 {
+		numBytes++
+		i >>= 8
+	}
+
+	return
+}
+
+func marshalBigInt(out *forkableWriter, n *big.Int) (err error) {
+	if n.Sign() < 0 {
+		// A negative number has to be converted to two's-complement
+		// form. So we'll subtract 1 and invert. If the
+		// most-significant-bit isn't set then we'll need to pad the
+		// beginning with 0xff in order to keep the number negative.
+		nMinus1 := new(big.Int).Neg(n)
+		nMinus1.Sub(nMinus1, bigOne)
+		bytes := nMinus1.Bytes()
+		for i := range bytes {
+			bytes[i] ^= 0xff
+		}
+		if len(bytes) == 0 || bytes[0]&0x80 == 0 {
+			err = out.WriteByte(0xff)
+			if err != nil {
+				return
+			}
+		}
+		_, err = out.Write(bytes)
+	} else if n.Sign() == 0 {
+		// Zero is written as a single 0 zero rather than no bytes.
+		err = out.WriteByte(0x00)
+	} else {
+		bytes := n.Bytes()
+		if len(bytes) > 0 && bytes[0]&0x80 != 0 {
+			// We'll have to pad this with 0x00 in order to stop it
+			// looking like a negative number.
+			err = out.WriteByte(0)
+			if err != nil {
+				return
+			}
+		}
+		_, err = out.Write(bytes)
+	}
+	return
+}
+
+func marshalLength(out *forkableWriter, i int) (err error) {
+	n := lengthLength(i)
+
+	for ; n > 0; n-- {
+		err = out.WriteByte(byte(i >> uint((n-1)*8)))
+		if err != nil {
+			return
+		}
+	}
+
+	return nil
+}
+
+func lengthLength(i int) (numBytes int) {
+	numBytes = 1
+	for i > 255 {
+		numBytes++
+		i >>= 8
+	}
+	return
+}
+
+func marshalTagAndLength(out *forkableWriter, t tagAndLength) (err error) {
+	b := uint8(t.class) << 6
+	if t.isCompound {
+		b |= 0x20
+	}
+	if t.tag >= 31 {
+		b |= 0x1f
+		err = out.WriteByte(b)
+		if err != nil {
+			return
+		}
+		err = marshalBase128Int(out, int64(t.tag))
+		if err != nil {
+			return
+		}
+	} else {
+		b |= uint8(t.tag)
+		err = out.WriteByte(b)
+		if err != nil {
+			return
+		}
+	}
+
+	if t.length >= 128 {
+		l := lengthLength(t.length)
+		err = out.WriteByte(0x80 | byte(l))
+		if err != nil {
+			return
+		}
+		err = marshalLength(out, t.length)
+		if err != nil {
+			return
+		}
+	} else {
+		err = out.WriteByte(byte(t.length))
+		if err != nil {
+			return
+		}
+	}
+
+	return nil
+}
+
+func marshalBitString(out *forkableWriter, b BitString) (err error) {
+	paddingBits := byte((8 - b.BitLength%8) % 8)
+	err = out.WriteByte(paddingBits)
+	if err != nil {
+		return
+	}
+	_, err = out.Write(b.Bytes)
+	return
+}
+
+func marshalObjectIdentifier(out *forkableWriter, oid []int) (err error) {
+	if len(oid) < 2 || oid[0] > 6 || oid[1] >= 40 {
+		return StructuralError{"invalid object identifier"}
+	}
+
+	err = out.WriteByte(byte(oid[0]*40 + oid[1]))
+	if err != nil {
+		return
+	}
+	for i := 2; i < len(oid); i++ {
+		err = marshalBase128Int(out, int64(oid[i]))
+		if err != nil {
+			return
+		}
+	}
+
+	return
+}
+
+func marshalPrintableString(out *forkableWriter, s string) (err error) {
+	b := []byte(s)
+	for _, c := range b {
+		if !isPrintable(c) {
+			return StructuralError{"PrintableString contains invalid character"}
+		}
+	}
+
+	_, err = out.Write(b)
+	return
+}
+
+func marshalIA5String(out *forkableWriter, s string) (err error) {
+	b := []byte(s)
+	for _, c := range b {
+		if c > 127 {
+			return StructuralError{"IA5String contains invalid character"}
+		}
+	}
+
+	_, err = out.Write(b)
+	return
+}
+
+func marshalTwoDigits(out *forkableWriter, v int) (err error) {
+	err = out.WriteByte(byte('0' + (v/10)%10))
+	if err != nil {
+		return
+	}
+	return out.WriteByte(byte('0' + v%10))
+}
+
+func marshalUTCTime(out *forkableWriter, t *time.Time) (err error) {
+	switch {
+	case 1950 <= t.Year && t.Year < 2000:
+		err = marshalTwoDigits(out, int(t.Year-1900))
+	case 2000 <= t.Year && t.Year < 2050:
+		err = marshalTwoDigits(out, int(t.Year-2000))
+	default:
+		return StructuralError{"Cannot represent time as UTCTime"}
+	}
+
+	if err != nil {
+		return
+	}
+
+	err = marshalTwoDigits(out, t.Month)
+	if err != nil {
+		return
+	}
+
+	err = marshalTwoDigits(out, t.Day)
+	if err != nil {
+		return
+	}
+
+	err = marshalTwoDigits(out, t.Hour)
+	if err != nil {
+		return
+	}
+
+	err = marshalTwoDigits(out, t.Minute)
+	if err != nil {
+		return
+	}
+
+	err = marshalTwoDigits(out, t.Second)
+	if err != nil {
+		return
+	}
+
+	switch {
+	case t.ZoneOffset/60 == 0:
+		err = out.WriteByte('Z')
+		return
+	case t.ZoneOffset > 0:
+		err = out.WriteByte('+')
+	case t.ZoneOffset < 0:
+		err = out.WriteByte('-')
+	}
+
+	if err != nil {
+		return
+	}
+
+	offsetMinutes := t.ZoneOffset / 60
+	if offsetMinutes < 0 {
+		offsetMinutes = -offsetMinutes
+	}
+
+	err = marshalTwoDigits(out, offsetMinutes/60)
+	if err != nil {
+		return
+	}
+
+	err = marshalTwoDigits(out, offsetMinutes%60)
+	return
+}
+
+func stripTagAndLength(in []byte) []byte {
+	_, offset, err := parseTagAndLength(in, 0)
+	if err != nil {
+		return in
+	}
+	return in[offset:]
+}
+
+func marshalBody(out *forkableWriter, value reflect.Value, params fieldParameters) (err error) {
+	switch value.Type() {
+	case timeType:
+		return marshalUTCTime(out, value.Interface().(*time.Time))
+	case bitStringType:
+		return marshalBitString(out, value.Interface().(BitString))
+	case objectIdentifierType:
+		return marshalObjectIdentifier(out, value.Interface().(ObjectIdentifier))
+	case bigIntType:
+		return marshalBigInt(out, value.Interface().(*big.Int))
+	}
+
+	switch v := value; v.Kind() {
+	case reflect.Bool:
+		if v.Bool() {
+			return out.WriteByte(255)
+		} else {
+			return out.WriteByte(0)
+		}
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		return marshalInt64(out, int64(v.Int()))
+	case reflect.Struct:
+		t := v.Type()
+
+		startingField := 0
+
+		// If the first element of the structure is a non-empty
+		// RawContents, then we don't bother serializing the rest.
+		if t.NumField() > 0 && t.Field(0).Type == rawContentsType {
+			s := v.Field(0)
+			if s.Len() > 0 {
+				bytes := make([]byte, s.Len())
+				for i := 0; i < s.Len(); i++ {
+					bytes[i] = uint8(s.Index(i).Uint())
+				}
+				/* The RawContents will contain the tag and
+				 * length fields but we'll also be writing
+				 * those ourselves, so we strip them out of
+				 * bytes */
+				_, err = out.Write(stripTagAndLength(bytes))
+				return
+			} else {
+				startingField = 1
+			}
+		}
+
+		for i := startingField; i < t.NumField(); i++ {
+			var pre *forkableWriter
+			pre, out = out.fork()
+			err = marshalField(pre, v.Field(i), parseFieldParameters(t.Field(i).Tag.Get("asn1")))
+			if err != nil {
+				return
+			}
+		}
+		return
+	case reflect.Slice:
+		sliceType := v.Type()
+		if sliceType.Elem().Kind() == reflect.Uint8 {
+			bytes := make([]byte, v.Len())
+			for i := 0; i < v.Len(); i++ {
+				bytes[i] = uint8(v.Index(i).Uint())
+			}
+			_, err = out.Write(bytes)
+			return
+		}
+
+		var params fieldParameters
+		for i := 0; i < v.Len(); i++ {
+			var pre *forkableWriter
+			pre, out = out.fork()
+			err = marshalField(pre, v.Index(i), params)
+			if err != nil {
+				return
+			}
+		}
+		return
+	case reflect.String:
+		if params.stringType == tagIA5String {
+			return marshalIA5String(out, v.String())
+		} else {
+			return marshalPrintableString(out, v.String())
+		}
+		return
+	}
+
+	return StructuralError{"unknown Go type"}
+}
+
+func marshalField(out *forkableWriter, v reflect.Value, params fieldParameters) (err error) {
+	// If the field is an interface{} then recurse into it.
+	if v.Kind() == reflect.Interface && v.Type().NumMethod() == 0 {
+		return marshalField(out, v.Elem(), params)
+	}
+
+	if params.optional && reflect.DeepEqual(v.Interface(), reflect.Zero(v.Type()).Interface()) {
+		return
+	}
+
+	if v.Type() == rawValueType {
+		rv := v.Interface().(RawValue)
+		if len(rv.FullBytes) != 0 {
+			_, err = out.Write(rv.FullBytes)
+		} else {
+			err = marshalTagAndLength(out, tagAndLength{rv.Class, rv.Tag, len(rv.Bytes), rv.IsCompound})
+			if err != nil {
+				return
+			}
+			_, err = out.Write(rv.Bytes)
+		}
+		return
+	}
+
+	tag, isCompound, ok := getUniversalType(v.Type())
+	if !ok {
+		err = StructuralError{fmt.Sprintf("unknown Go type: %v", v.Type())}
+		return
+	}
+	class := classUniversal
+
+	if params.stringType != 0 {
+		if tag != tagPrintableString {
+			return StructuralError{"Explicit string type given to non-string member"}
+		}
+		tag = params.stringType
+	}
+
+	if params.set {
+		if tag != tagSequence {
+			return StructuralError{"Non sequence tagged as set"}
+		}
+		tag = tagSet
+	}
+
+	tags, body := out.fork()
+
+	err = marshalBody(body, v, params)
+	if err != nil {
+		return
+	}
+
+	bodyLen := body.Len()
+
+	var explicitTag *forkableWriter
+	if params.explicit {
+		explicitTag, tags = tags.fork()
+	}
+
+	if !params.explicit && params.tag != nil {
+		// implicit tag.
+		tag = *params.tag
+		class = classContextSpecific
+	}
+
+	err = marshalTagAndLength(tags, tagAndLength{class, tag, bodyLen, isCompound})
+	if err != nil {
+		return
+	}
+
+	if params.explicit {
+		err = marshalTagAndLength(explicitTag, tagAndLength{
+			class:      classContextSpecific,
+			tag:        *params.tag,
+			length:     bodyLen + tags.Len(),
+			isCompound: true,
+		})
+	}
+
+	return nil
+}
+
+// Marshal returns the ASN.1 encoding of val.
+func Marshal(val interface{}) ([]byte, error) {
+	var out bytes.Buffer
+	v := reflect.ValueOf(val)
+	f := newForkableWriter()
+	err := marshalField(f, v, fieldParameters{})
+	if err != nil {
+		return nil, err
+	}
+	_, err = f.writeTo(&out)
+	return out.Bytes(), nil
+}
diff --git a/libgo/go/encoding/asn1/marshal_test.go b/libgo/go/encoding/asn1/marshal_test.go
new file mode 100644
index 00000000000..03df5f1e1d5
--- /dev/null
+++ b/libgo/go/encoding/asn1/marshal_test.go
@@ -0,0 +1,129 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package asn1
+
+import (
+	"bytes"
+	"encoding/hex"
+	"testing"
+	"time"
+)
+
+type intStruct struct {
+	A int
+}
+
+type twoIntStruct struct {
+	A int
+	B int
+}
+
+type nestedStruct struct {
+	A intStruct
+}
+
+type rawContentsStruct struct {
+	Raw RawContent
+	A   int
+}
+
+type implicitTagTest struct {
+	A int `asn1:"implicit,tag:5"`
+}
+
+type explicitTagTest struct {
+	A int `asn1:"explicit,tag:5"`
+}
+
+type ia5StringTest struct {
+	A string `asn1:"ia5"`
+}
+
+type printableStringTest struct {
+	A string `asn1:"printable"`
+}
+
+type optionalRawValueTest struct {
+	A RawValue `asn1:"optional"`
+}
+
+type testSET []int
+
+func setPST(t *time.Time) *time.Time {
+	t.ZoneOffset = -28800
+	return t
+}
+
+type marshalTest struct {
+	in  interface{}
+	out string // hex encoded
+}
+
+var marshalTests = []marshalTest{
+	{10, "02010a"},
+	{127, "02017f"},
+	{128, "02020080"},
+	{-128, "020180"},
+	{-129, "0202ff7f"},
+	{intStruct{64}, "3003020140"},
+	{twoIntStruct{64, 65}, "3006020140020141"},
+	{nestedStruct{intStruct{127}}, "3005300302017f"},
+	{[]byte{1, 2, 3}, "0403010203"},
+	{implicitTagTest{64}, "3003850140"},
+	{explicitTagTest{64}, "3005a503020140"},
+	{time.SecondsToUTC(0), "170d3730303130313030303030305a"},
+	{time.SecondsToUTC(1258325776), "170d3039313131353232353631365a"},
+	{setPST(time.SecondsToUTC(1258325776)), "17113039313131353232353631362d30383030"},
+	{BitString{[]byte{0x80}, 1}, "03020780"},
+	{BitString{[]byte{0x81, 0xf0}, 12}, "03030481f0"},
+	{ObjectIdentifier([]int{1, 2, 3, 4}), "06032a0304"},
+	{ObjectIdentifier([]int{1, 2, 840, 133549, 1, 1, 5}), "06092a864888932d010105"},
+	{"test", "130474657374"},
+	{
+		"" +
+			"xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx" +
+			"xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx" +
+			"xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx" +
+			"xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx", // This is 127 times 'x'
+		"137f" +
+			"7878787878787878787878787878787878787878787878787878787878787878" +
+			"7878787878787878787878787878787878787878787878787878787878787878" +
+			"7878787878787878787878787878787878787878787878787878787878787878" +
+			"78787878787878787878787878787878787878787878787878787878787878",
+	},
+	{
+		"" +
+			"xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx" +
+			"xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx" +
+			"xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx" +
+			"xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx", // This is 128 times 'x'
+		"138180" +
+			"7878787878787878787878787878787878787878787878787878787878787878" +
+			"7878787878787878787878787878787878787878787878787878787878787878" +
+			"7878787878787878787878787878787878787878787878787878787878787878" +
+			"7878787878787878787878787878787878787878787878787878787878787878",
+	},
+	{ia5StringTest{"test"}, "3006160474657374"},
+	{optionalRawValueTest{}, "3000"},
+	{printableStringTest{"test"}, "3006130474657374"},
+	{printableStringTest{"test*"}, "30071305746573742a"},
+	{rawContentsStruct{nil, 64}, "3003020140"},
+	{rawContentsStruct{[]byte{0x30, 3, 1, 2, 3}, 64}, "3003010203"},
+	{RawValue{Tag: 1, Class: 2, IsCompound: false, Bytes: []byte{1, 2, 3}}, "8103010203"},
+	{testSET([]int{10}), "310302010a"},
+}
+
+func TestMarshal(t *testing.T) {
+	for i, test := range marshalTests {
+		data, err := Marshal(test.in)
+		if err != nil {
+			t.Errorf("#%d failed: %s", i, err)
+		}
+		out, _ := hex.DecodeString(test.out)
+		if bytes.Compare(out, data) != 0 {
+			t.Errorf("#%d got: %x want %x", i, data, out)
+		}
+	}
+}
diff --git a/libgo/go/encoding/binary/binary.go b/libgo/go/encoding/binary/binary.go
index 65b9f013fcd..d2f8b1e6248 100644
--- a/libgo/go/encoding/binary/binary.go
+++ b/libgo/go/encoding/binary/binary.go
@@ -9,8 +9,8 @@ package binary
 
 import (
 	"errors"
-	"math"
 	"io"
+	"math"
 	"reflect"
 )
 
diff --git a/libgo/go/encoding/binary/binary_test.go b/libgo/go/encoding/binary/binary_test.go
index e753aa0b5b6..fd4fdb01574 100644
--- a/libgo/go/encoding/binary/binary_test.go
+++ b/libgo/go/encoding/binary/binary_test.go
@@ -7,7 +7,6 @@ package binary
 import (
 	"bytes"
 	"io"
-	"bytes"
 	"math"
 	"reflect"
 	"testing"
diff --git a/libgo/go/encoding/csv/reader.go b/libgo/go/encoding/csv/reader.go
new file mode 100644
index 00000000000..ae0f567b9df
--- /dev/null
+++ b/libgo/go/encoding/csv/reader.go
@@ -0,0 +1,372 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package csv reads and writes comma-separated values (CSV) files.
+//
+// A csv file contains zero or more records of one or more fields per record.
+// Each record is separated by the newline character. The final record may
+// optionally be followed by a newline character.
+//
+//	field1,field2,field3
+//
+// White space is considered part of a field.
+//
+// Carriage returns before newline characters are silently removed.
+//
+// Blank lines are ignored.  A line with only whitespace characters (excluding
+// the ending newline character) is not considered a blank line.
+//
+// Fields which start and stop with the quote character " are called
+// quoted-fields.  The beginning and ending quote are not part of the
+// field.
+//
+// The source:
+//
+//	normal string,"quoted-field"
+//
+// results in the fields
+//
+//	{`normal string`, `quoted-field`}
+//
+// Within a quoted-field a quote character followed by a second quote
+// character is considered a single quote.
+//
+//	"the ""word"" is true","a ""quoted-field"""
+//
+// results in
+//
+//	{`the "word" is true`, `a "quoted-field"`}
+//
+// Newlines and commas may be included in a quoted-field
+//
+//	"Multi-line
+//	field","comma is ,"
+//
+// results in
+//
+//	{`Multi-line
+//	field`, `comma is ,`}
+package csv
+
+import (
+	"bufio"
+	"bytes"
+	"errors"
+	"fmt"
+	"io"
+	"unicode"
+)
+
+// A ParseError is returned for parsing errors.
+// The first line is 1.  The first column is 0.
+type ParseError struct {
+	Line   int   // Line where the error occurred
+	Column int   // Column (rune index) where the error occurred
+	Err    error // The actual error
+}
+
+func (e *ParseError) Error() string {
+	return fmt.Sprintf("line %d, column %d: %s", e.Line, e.Column, e.Err)
+}
+
+// These are the errors that can be returned in ParseError.Error
+var (
+	ErrTrailingComma = errors.New("extra delimiter at end of line")
+	ErrBareQuote     = errors.New("bare \" in non-quoted-field")
+	ErrQuote         = errors.New("extraneous \" in field")
+	ErrFieldCount    = errors.New("wrong number of fields in line")
+)
+
+// A Reader reads records from a CSV-encoded file.
+//
+// As returned by NewReader, a Reader expects input conforming to RFC 4180.
+// The exported fields can be changed to customize the details before the
+// first call to Read or ReadAll.
+//
+// Comma is the field delimiter.  It defaults to ','.
+//
+// Comment, if not 0, is the comment character. Lines beginning with the
+// Comment character are ignored.
+//
+// If FieldsPerRecord is positive, Read requires each record to
+// have the given number of fields.  If FieldsPerRecord is 0, Read sets it to
+// the number of fields in the first record, so that future records must
+// have the same field count.
+//
+// If LazyQuotes is true, a quote may appear in an unquoted field and a
+// non-doubled quote may appear in a quoted field.
+//
+// If TrailingComma is true, the last field may be an unquoted empty field.
+//
+// If TrimLeadingSpace is true, leading white space in a field is ignored.
+type Reader struct {
+	Comma            rune // Field delimiter (set to ',' by NewReader)
+	Comment          rune // Comment character for start of line
+	FieldsPerRecord  int  // Number of expected fields per record
+	LazyQuotes       bool // Allow lazy quotes
+	TrailingComma    bool // Allow trailing comma
+	TrimLeadingSpace bool // Trim leading space
+	line             int
+	column           int
+	r                *bufio.Reader
+	field            bytes.Buffer
+}
+
+// NewReader returns a new Reader that reads from r.
+func NewReader(r io.Reader) *Reader {
+	return &Reader{
+		Comma: ',',
+		r:     bufio.NewReader(r),
+	}
+}
+
+// error creates a new ParseError based on err.
+func (r *Reader) error(err error) error {
+	return &ParseError{
+		Line:   r.line,
+		Column: r.column,
+		Err:    err,
+	}
+}
+
+// Read reads one record from r.  The record is a slice of strings with each
+// string representing one field.
+func (r *Reader) Read() (record []string, err error) {
+	for {
+		record, err = r.parseRecord()
+		if record != nil {
+			break
+		}
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	if r.FieldsPerRecord > 0 {
+		if len(record) != r.FieldsPerRecord {
+			r.column = 0 // report at start of record
+			return record, r.error(ErrFieldCount)
+		}
+	} else if r.FieldsPerRecord == 0 {
+		r.FieldsPerRecord = len(record)
+	}
+	return record, nil
+}
+
+// ReadAll reads all the remaining records from r.
+// Each record is a slice of fields.
+func (r *Reader) ReadAll() (records [][]string, err error) {
+	for {
+		record, err := r.Read()
+		if err == io.EOF {
+			return records, nil
+		}
+		if err != nil {
+			return nil, err
+		}
+		records = append(records, record)
+	}
+	panic("unreachable")
+}
+
+// readRune reads one rune from r, folding \r\n to \n and keeping track
+// of how far into the line we have read.  r.column will point to the start
+// of this rune, not the end of this rune.
+func (r *Reader) readRune() (rune, error) {
+	r1, _, err := r.r.ReadRune()
+
+	// Handle \r\n here.  We make the simplifying assumption that
+	// anytime \r is followed by \n that it can be folded to \n.
+	// We will not detect files which contain both \r\n and bare \n.
+	if r1 == '\r' {
+		r1, _, err = r.r.ReadRune()
+		if err == nil {
+			if r1 != '\n' {
+				r.r.UnreadRune()
+				r1 = '\r'
+			}
+		}
+	}
+	r.column++
+	return r1, err
+}
+
+// unreadRune puts the last rune read from r back.
+func (r *Reader) unreadRune() {
+	r.r.UnreadRune()
+	r.column--
+}
+
+// skip reads runes up to and including the rune delim or until error.
+func (r *Reader) skip(delim rune) error {
+	for {
+		r1, err := r.readRune()
+		if err != nil {
+			return err
+		}
+		if r1 == delim {
+			return nil
+		}
+	}
+	panic("unreachable")
+}
+
+// parseRecord reads and parses a single csv record from r.
+func (r *Reader) parseRecord() (fields []string, err error) {
+	// Each record starts on a new line.  We increment our line
+	// number (lines start at 1, not 0) and set column to -1
+	// so as we increment in readRune it points to the character we read.
+	r.line++
+	r.column = -1
+
+	// Peek at the first rune.  If it is an error we are done.
+	// If we are support comments and it is the comment character
+	// then skip to the end of line.
+
+	r1, _, err := r.r.ReadRune()
+	if err != nil {
+		return nil, err
+	}
+
+	if r.Comment != 0 && r1 == r.Comment {
+		return nil, r.skip('\n')
+	}
+	r.r.UnreadRune()
+
+	// At this point we have at least one field.
+	for {
+		haveField, delim, err := r.parseField()
+		if haveField {
+			fields = append(fields, r.field.String())
+		}
+		if delim == '\n' || err == io.EOF {
+			return fields, err
+		} else if err != nil {
+			return nil, err
+		}
+	}
+	panic("unreachable")
+}
+
+// parseField parses the next field in the record.  The read field is
+// located in r.field.  Delim is the first character not part of the field
+// (r.Comma or '\n').
+func (r *Reader) parseField() (haveField bool, delim rune, err error) {
+	r.field.Reset()
+
+	r1, err := r.readRune()
+	if err != nil {
+		// If we have EOF and are not at the start of a line
+		// then we return the empty field.  We have already
+		// checked for trailing commas if needed.
+		if err == io.EOF && r.column != 0 {
+			return true, 0, err
+		}
+		return false, 0, err
+	}
+
+	if r.TrimLeadingSpace {
+		for r1 != '\n' && unicode.IsSpace(r1) {
+			r1, err = r.readRune()
+			if err != nil {
+				return false, 0, err
+			}
+		}
+	}
+
+	switch r1 {
+	case r.Comma:
+		// will check below
+
+	case '\n':
+		// We are a trailing empty field or a blank line
+		if r.column == 0 {
+			return false, r1, nil
+		}
+		return true, r1, nil
+
+	case '"':
+		// quoted field
+	Quoted:
+		for {
+			r1, err = r.readRune()
+			if err != nil {
+				if err == io.EOF {
+					if r.LazyQuotes {
+						return true, 0, err
+					}
+					return false, 0, r.error(ErrQuote)
+				}
+				return false, 0, err
+			}
+			switch r1 {
+			case '"':
+				r1, err = r.readRune()
+				if err != nil || r1 == r.Comma {
+					break Quoted
+				}
+				if r1 == '\n' {
+					return true, r1, nil
+				}
+				if r1 != '"' {
+					if !r.LazyQuotes {
+						r.column--
+						return false, 0, r.error(ErrQuote)
+					}
+					// accept the bare quote
+					r.field.WriteRune('"')
+				}
+			case '\n':
+				r.line++
+				r.column = -1
+			}
+			r.field.WriteRune(r1)
+		}
+
+	default:
+		// unquoted field
+		for {
+			r.field.WriteRune(r1)
+			r1, err = r.readRune()
+			if err != nil || r1 == r.Comma {
+				break
+			}
+			if r1 == '\n' {
+				return true, r1, nil
+			}
+			if !r.LazyQuotes && r1 == '"' {
+				return false, 0, r.error(ErrBareQuote)
+			}
+		}
+	}
+
+	if err != nil {
+		if err == io.EOF {
+			return true, 0, err
+		}
+		return false, 0, err
+	}
+
+	if !r.TrailingComma {
+		// We don't allow trailing commas.  See if we
+		// are at the end of the line (being mindful
+		// of trimming spaces).
+		c := r.column
+		r1, err = r.readRune()
+		if r.TrimLeadingSpace {
+			for r1 != '\n' && unicode.IsSpace(r1) {
+				r1, err = r.readRune()
+				if err != nil {
+					break
+				}
+			}
+		}
+		if err == io.EOF || r1 == '\n' {
+			r.column = c // report the comma
+			return false, 0, r.error(ErrTrailingComma)
+		}
+		r.unreadRune()
+	}
+	return true, r1, nil
+}
diff --git a/libgo/go/encoding/csv/reader_test.go b/libgo/go/encoding/csv/reader_test.go
new file mode 100644
index 00000000000..5fd84a76bdf
--- /dev/null
+++ b/libgo/go/encoding/csv/reader_test.go
@@ -0,0 +1,281 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package csv
+
+import (
+	"reflect"
+	"strings"
+	"testing"
+)
+
+var readTests = []struct {
+	Name               string
+	Input              string
+	Output             [][]string
+	UseFieldsPerRecord bool // false (default) means FieldsPerRecord is -1
+
+	// These fields are copied into the Reader
+	Comma            rune
+	Comment          rune
+	FieldsPerRecord  int
+	LazyQuotes       bool
+	TrailingComma    bool
+	TrimLeadingSpace bool
+
+	Error  string
+	Line   int // Expected error line if != 0
+	Column int // Expected error column if line != 0
+}{
+	{
+		Name:   "Simple",
+		Input:  "a,b,c\n",
+		Output: [][]string{{"a", "b", "c"}},
+	},
+	{
+		Name:   "CRLF",
+		Input:  "a,b\r\nc,d\r\n",
+		Output: [][]string{{"a", "b"}, {"c", "d"}},
+	},
+	{
+		Name:   "BareCR",
+		Input:  "a,b\rc,d\r\n",
+		Output: [][]string{{"a", "b\rc", "d"}},
+	},
+	{
+		Name:               "RFC4180test",
+		UseFieldsPerRecord: true,
+		Input: `#field1,field2,field3
+"aaa","bb
+b","ccc"
+"a,a","b""bb","ccc"
+zzz,yyy,xxx
+`,
+		Output: [][]string{
+			{"#field1", "field2", "field3"},
+			{"aaa", "bb\nb", "ccc"},
+			{"a,a", `b"bb`, "ccc"},
+			{"zzz", "yyy", "xxx"},
+		},
+	},
+	{
+		Name:   "NoEOLTest",
+		Input:  "a,b,c",
+		Output: [][]string{{"a", "b", "c"}},
+	},
+	{
+		Name:   "Semicolon",
+		Comma:  ';',
+		Input:  "a;b;c\n",
+		Output: [][]string{{"a", "b", "c"}},
+	},
+	{
+		Name: "MultiLine",
+		Input: `"two
+line","one line","three
+line
+field"`,
+		Output: [][]string{{"two\nline", "one line", "three\nline\nfield"}},
+	},
+	{
+		Name:  "BlankLine",
+		Input: "a,b,c\n\nd,e,f\n\n",
+		Output: [][]string{
+			{"a", "b", "c"},
+			{"d", "e", "f"},
+		},
+	},
+	{
+		Name:             "TrimSpace",
+		Input:            " a,  b,   c\n",
+		TrimLeadingSpace: true,
+		Output:           [][]string{{"a", "b", "c"}},
+	},
+	{
+		Name:   "LeadingSpace",
+		Input:  " a,  b,   c\n",
+		Output: [][]string{{" a", "  b", "   c"}},
+	},
+	{
+		Name:    "Comment",
+		Comment: '#',
+		Input:   "#1,2,3\na,b,c\n#comment",
+		Output:  [][]string{{"a", "b", "c"}},
+	},
+	{
+		Name:   "NoComment",
+		Input:  "#1,2,3\na,b,c",
+		Output: [][]string{{"#1", "2", "3"}, {"a", "b", "c"}},
+	},
+	{
+		Name:       "LazyQuotes",
+		LazyQuotes: true,
+		Input:      `a "word","1"2",a","b`,
+		Output:     [][]string{{`a "word"`, `1"2`, `a"`, `b`}},
+	},
+	{
+		Name:       "BareQuotes",
+		LazyQuotes: true,
+		Input:      `a "word","1"2",a"`,
+		Output:     [][]string{{`a "word"`, `1"2`, `a"`}},
+	},
+	{
+		Name:       "BareDoubleQuotes",
+		LazyQuotes: true,
+		Input:      `a""b,c`,
+		Output:     [][]string{{`a""b`, `c`}},
+	},
+	{
+		Name:  "BadDoubleQuotes",
+		Input: `a""b,c`,
+		Error: `bare " in non-quoted-field`, Line: 1, Column: 1,
+	},
+	{
+		Name:             "TrimQuote",
+		Input:            ` "a"," b",c`,
+		TrimLeadingSpace: true,
+		Output:           [][]string{{"a", " b", "c"}},
+	},
+	{
+		Name:  "BadBareQuote",
+		Input: `a "word","b"`,
+		Error: `bare " in non-quoted-field`, Line: 1, Column: 2,
+	},
+	{
+		Name:  "BadTrailingQuote",
+		Input: `"a word",b"`,
+		Error: `bare " in non-quoted-field`, Line: 1, Column: 10,
+	},
+	{
+		Name:  "ExtraneousQuote",
+		Input: `"a "word","b"`,
+		Error: `extraneous " in field`, Line: 1, Column: 3,
+	},
+	{
+		Name:               "BadFieldCount",
+		UseFieldsPerRecord: true,
+		Input:              "a,b,c\nd,e",
+		Error:              "wrong number of fields", Line: 2,
+	},
+	{
+		Name:               "BadFieldCount1",
+		UseFieldsPerRecord: true,
+		FieldsPerRecord:    2,
+		Input:              `a,b,c`,
+		Error:              "wrong number of fields", Line: 1,
+	},
+	{
+		Name:   "FieldCount",
+		Input:  "a,b,c\nd,e",
+		Output: [][]string{{"a", "b", "c"}, {"d", "e"}},
+	},
+	{
+		Name:  "BadTrailingCommaEOF",
+		Input: "a,b,c,",
+		Error: "extra delimiter at end of line", Line: 1, Column: 5,
+	},
+	{
+		Name:  "BadTrailingCommaEOL",
+		Input: "a,b,c,\n",
+		Error: "extra delimiter at end of line", Line: 1, Column: 5,
+	},
+	{
+		Name:             "BadTrailingCommaSpaceEOF",
+		TrimLeadingSpace: true,
+		Input:            "a,b,c, ",
+		Error:            "extra delimiter at end of line", Line: 1, Column: 5,
+	},
+	{
+		Name:             "BadTrailingCommaSpaceEOL",
+		TrimLeadingSpace: true,
+		Input:            "a,b,c, \n",
+		Error:            "extra delimiter at end of line", Line: 1, Column: 5,
+	},
+	{
+		Name:             "BadTrailingCommaLine3",
+		TrimLeadingSpace: true,
+		Input:            "a,b,c\nd,e,f\ng,hi,",
+		Error:            "extra delimiter at end of line", Line: 3, Column: 4,
+	},
+	{
+		Name:   "NotTrailingComma3",
+		Input:  "a,b,c, \n",
+		Output: [][]string{{"a", "b", "c", " "}},
+	},
+	{
+		Name:          "CommaFieldTest",
+		TrailingComma: true,
+		Input: `x,y,z,w
+x,y,z,
+x,y,,
+x,,,
+,,,
+"x","y","z","w"
+"x","y","z",""
+"x","y","",""
+"x","","",""
+"","","",""
+`,
+		Output: [][]string{
+			{"x", "y", "z", "w"},
+			{"x", "y", "z", ""},
+			{"x", "y", "", ""},
+			{"x", "", "", ""},
+			{"", "", "", ""},
+			{"x", "y", "z", "w"},
+			{"x", "y", "z", ""},
+			{"x", "y", "", ""},
+			{"x", "", "", ""},
+			{"", "", "", ""},
+		},
+	},
+	{
+		Name:             "Issue 2366",
+		TrailingComma:    true,
+		TrimLeadingSpace: true,
+		Input:            "a,b,\nc,d,e",
+		Output: [][]string{
+			{"a", "b", ""},
+			{"c", "d", "e"},
+		},
+	},
+	{
+		Name:             "Issue 2366a",
+		TrailingComma:    false,
+		TrimLeadingSpace: true,
+		Input:            "a,b,\nc,d,e",
+		Error:            "extra delimiter at end of line",
+	},
+}
+
+func TestRead(t *testing.T) {
+	for _, tt := range readTests {
+		r := NewReader(strings.NewReader(tt.Input))
+		r.Comment = tt.Comment
+		if tt.UseFieldsPerRecord {
+			r.FieldsPerRecord = tt.FieldsPerRecord
+		} else {
+			r.FieldsPerRecord = -1
+		}
+		r.LazyQuotes = tt.LazyQuotes
+		r.TrailingComma = tt.TrailingComma
+		r.TrimLeadingSpace = tt.TrimLeadingSpace
+		if tt.Comma != 0 {
+			r.Comma = tt.Comma
+		}
+		out, err := r.ReadAll()
+		perr, _ := err.(*ParseError)
+		if tt.Error != "" {
+			if err == nil || !strings.Contains(err.Error(), tt.Error) {
+				t.Errorf("%s: error %v, want error %q", tt.Name, err, tt.Error)
+			} else if tt.Line != 0 && (tt.Line != perr.Line || tt.Column != perr.Column) {
+				t.Errorf("%s: error at %d:%d expected %d:%d", tt.Name, perr.Line, perr.Column, tt.Line, tt.Column)
+			}
+		} else if err != nil {
+			t.Errorf("%s: unexpected error %v", tt.Name, err)
+		} else if !reflect.DeepEqual(out, tt.Output) {
+			t.Errorf("%s: out=%q want %q", tt.Name, out, tt.Output)
+		}
+	}
+}
diff --git a/libgo/go/encoding/csv/writer.go b/libgo/go/encoding/csv/writer.go
new file mode 100644
index 00000000000..c4dcba5668a
--- /dev/null
+++ b/libgo/go/encoding/csv/writer.go
@@ -0,0 +1,121 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package csv
+
+import (
+	"bufio"
+	"io"
+	"strings"
+	"unicode"
+	"unicode/utf8"
+)
+
+// A Writer writes records to a CSV encoded file.
+//
+// As returned by NewWriter, a Writer writes records terminated by a
+// newline and uses ',' as the field delimiter.  The exported fields can be
+// changed to customize the details before the first call to Write or WriteAll.
+//
+// Comma is the field delimiter.
+//
+// If UseCRLF is true, the Writer ends each record with \r\n instead of \n.
+type Writer struct {
+	Comma   rune // Field delimiter (set to to ',' by NewWriter)
+	UseCRLF bool // True to use \r\n as the line terminator
+	w       *bufio.Writer
+}
+
+// NewWriter returns a new Writer that writes to w.
+func NewWriter(w io.Writer) *Writer {
+	return &Writer{
+		Comma: ',',
+		w:     bufio.NewWriter(w),
+	}
+}
+
+// Writer writes a single CSV record to w along with any necessary quoting.
+// A record is a slice of strings with each string being one field.
+func (w *Writer) Write(record []string) (err error) {
+	for n, field := range record {
+		if n > 0 {
+			if _, err = w.w.WriteRune(w.Comma); err != nil {
+				return
+			}
+		}
+
+		// If we don't have to have a quoted field then just
+		// write out the field and continue to the next field.
+		if !w.fieldNeedsQuotes(field) {
+			if _, err = w.w.WriteString(field); err != nil {
+				return
+			}
+			continue
+		}
+		if err = w.w.WriteByte('"'); err != nil {
+			return
+		}
+
+		for _, r1 := range field {
+			switch r1 {
+			case '"':
+				_, err = w.w.WriteString(`""`)
+			case '\r':
+				if !w.UseCRLF {
+					err = w.w.WriteByte('\r')
+				}
+			case '\n':
+				if w.UseCRLF {
+					_, err = w.w.WriteString("\r\n")
+				} else {
+					err = w.w.WriteByte('\n')
+				}
+			default:
+				_, err = w.w.WriteRune(r1)
+			}
+			if err != nil {
+				return
+			}
+		}
+
+		if err = w.w.WriteByte('"'); err != nil {
+			return
+		}
+	}
+	if w.UseCRLF {
+		_, err = w.w.WriteString("\r\n")
+	} else {
+		err = w.w.WriteByte('\n')
+	}
+	return
+}
+
+// Flush writes any buffered data to the underlying io.Writer.
+func (w *Writer) Flush() {
+	w.w.Flush()
+}
+
+// WriteAll writes multiple CSV records to w using Write and then calls Flush.
+func (w *Writer) WriteAll(records [][]string) (err error) {
+	for _, record := range records {
+		err = w.Write(record)
+		if err != nil {
+			break
+		}
+	}
+	w.Flush()
+	return nil
+}
+
+// fieldNeedsQuotes returns true if our field must be enclosed in quotes.
+// Empty fields, files with a Comma, fields with a quote or newline, and
+// fields which start with a space must be enclosed in quotes.
+func (w *Writer) fieldNeedsQuotes(field string) bool {
+	if len(field) == 0 || strings.IndexRune(field, w.Comma) >= 0 || strings.IndexAny(field, "\"\r\n") >= 0 {
+		return true
+	}
+
+	r1, _ := utf8.DecodeRuneInString(field)
+	return unicode.IsSpace(r1)
+}
diff --git a/libgo/go/encoding/csv/writer_test.go b/libgo/go/encoding/csv/writer_test.go
new file mode 100644
index 00000000000..578959007fd
--- /dev/null
+++ b/libgo/go/encoding/csv/writer_test.go
@@ -0,0 +1,44 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package csv
+
+import (
+	"bytes"
+	"testing"
+)
+
+var writeTests = []struct {
+	Input   [][]string
+	Output  string
+	UseCRLF bool
+}{
+	{Input: [][]string{{"abc"}}, Output: "abc\n"},
+	{Input: [][]string{{"abc"}}, Output: "abc\r\n", UseCRLF: true},
+	{Input: [][]string{{`"abc"`}}, Output: `"""abc"""` + "\n"},
+	{Input: [][]string{{`a"b`}}, Output: `"a""b"` + "\n"},
+	{Input: [][]string{{`"a"b"`}}, Output: `"""a""b"""` + "\n"},
+	{Input: [][]string{{" abc"}}, Output: `" abc"` + "\n"},
+	{Input: [][]string{{"abc,def"}}, Output: `"abc,def"` + "\n"},
+	{Input: [][]string{{"abc", "def"}}, Output: "abc,def\n"},
+	{Input: [][]string{{"abc"}, {"def"}}, Output: "abc\ndef\n"},
+	{Input: [][]string{{"abc\ndef"}}, Output: "\"abc\ndef\"\n"},
+	{Input: [][]string{{"abc\ndef"}}, Output: "\"abc\r\ndef\"\r\n", UseCRLF: true},
+}
+
+func TestWrite(t *testing.T) {
+	for n, tt := range writeTests {
+		b := &bytes.Buffer{}
+		f := NewWriter(b)
+		f.UseCRLF = tt.UseCRLF
+		err := f.WriteAll(tt.Input)
+		if err != nil {
+			t.Errorf("Unexpected error: %s\n", err)
+		}
+		out := b.String()
+		if out != tt.Output {
+			t.Errorf("#%d: out=%q want %q", n, out, tt.Output)
+		}
+	}
+}
diff --git a/libgo/go/encoding/gob/codec_test.go b/libgo/go/encoding/gob/codec_test.go
new file mode 100644
index 00000000000..dc0e0078e68
--- /dev/null
+++ b/libgo/go/encoding/gob/codec_test.go
@@ -0,0 +1,1406 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package gob
+
+import (
+	"bytes"
+	"errors"
+	"math"
+	"reflect"
+	"strings"
+	"testing"
+	"unsafe"
+)
+
+// Guarantee encoding format by comparing some encodings to hand-written values
+type EncodeT struct {
+	x uint64
+	b []byte
+}
+
+var encodeT = []EncodeT{
+	{0x00, []byte{0x00}},
+	{0x0F, []byte{0x0F}},
+	{0xFF, []byte{0xFF, 0xFF}},
+	{0xFFFF, []byte{0xFE, 0xFF, 0xFF}},
+	{0xFFFFFF, []byte{0xFD, 0xFF, 0xFF, 0xFF}},
+	{0xFFFFFFFF, []byte{0xFC, 0xFF, 0xFF, 0xFF, 0xFF}},
+	{0xFFFFFFFFFF, []byte{0xFB, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF}},
+	{0xFFFFFFFFFFFF, []byte{0xFA, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF}},
+	{0xFFFFFFFFFFFFFF, []byte{0xF9, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF}},
+	{0xFFFFFFFFFFFFFFFF, []byte{0xF8, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF}},
+	{0x1111, []byte{0xFE, 0x11, 0x11}},
+	{0x1111111111111111, []byte{0xF8, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11}},
+	{0x8888888888888888, []byte{0xF8, 0x88, 0x88, 0x88, 0x88, 0x88, 0x88, 0x88, 0x88}},
+	{1 << 63, []byte{0xF8, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}},
+}
+
+// testError is meant to be used as a deferred function to turn a panic(gobError) into a
+// plain test.Error call.
+func testError(t *testing.T) {
+	if e := recover(); e != nil {
+		t.Error(e.(gobError).err) // Will re-panic if not one of our errors, such as a runtime error.
+	}
+	return
+}
+
+// Test basic encode/decode routines for unsigned integers
+func TestUintCodec(t *testing.T) {
+	defer testError(t)
+	b := new(bytes.Buffer)
+	encState := newEncoderState(b)
+	for _, tt := range encodeT {
+		b.Reset()
+		encState.encodeUint(tt.x)
+		if !bytes.Equal(tt.b, b.Bytes()) {
+			t.Errorf("encodeUint: %#x encode: expected % x got % x", tt.x, tt.b, b.Bytes())
+		}
+	}
+	decState := newDecodeState(b)
+	for u := uint64(0); ; u = (u + 1) * 7 {
+		b.Reset()
+		encState.encodeUint(u)
+		v := decState.decodeUint()
+		if u != v {
+			t.Errorf("Encode/Decode: sent %#x received %#x", u, v)
+		}
+		if u&(1<<63) != 0 {
+			break
+		}
+	}
+}
+
+func verifyInt(i int64, t *testing.T) {
+	defer testError(t)
+	var b = new(bytes.Buffer)
+	encState := newEncoderState(b)
+	encState.encodeInt(i)
+	decState := newDecodeState(b)
+	decState.buf = make([]byte, 8)
+	j := decState.decodeInt()
+	if i != j {
+		t.Errorf("Encode/Decode: sent %#x received %#x", uint64(i), uint64(j))
+	}
+}
+
+// Test basic encode/decode routines for signed integers
+func TestIntCodec(t *testing.T) {
+	for u := uint64(0); ; u = (u + 1) * 7 {
+		// Do positive and negative values
+		i := int64(u)
+		verifyInt(i, t)
+		verifyInt(-i, t)
+		verifyInt(^i, t)
+		if u&(1<<63) != 0 {
+			break
+		}
+	}
+	verifyInt(-1<<63, t) // a tricky case
+}
+
+// The result of encoding a true boolean with field number 7
+var boolResult = []byte{0x07, 0x01}
+// The result of encoding a number 17 with field number 7
+var signedResult = []byte{0x07, 2 * 17}
+var unsignedResult = []byte{0x07, 17}
+var floatResult = []byte{0x07, 0xFE, 0x31, 0x40}
+// The result of encoding a number 17+19i with field number 7
+var complexResult = []byte{0x07, 0xFE, 0x31, 0x40, 0xFE, 0x33, 0x40}
+// The result of encoding "hello" with field number 7
+var bytesResult = []byte{0x07, 0x05, 'h', 'e', 'l', 'l', 'o'}
+
+func newDecodeState(buf *bytes.Buffer) *decoderState {
+	d := new(decoderState)
+	d.b = buf
+	d.buf = make([]byte, uint64Size)
+	return d
+}
+
+func newEncoderState(b *bytes.Buffer) *encoderState {
+	b.Reset()
+	state := &encoderState{enc: nil, b: b}
+	state.fieldnum = -1
+	return state
+}
+
+// Test instruction execution for encoding.
+// Do not run the machine yet; instead do individual instructions crafted by hand.
+func TestScalarEncInstructions(t *testing.T) {
+	var b = new(bytes.Buffer)
+
+	// bool
+	{
+		data := struct{ a bool }{true}
+		instr := &encInstr{encBool, 6, 0, 0}
+		state := newEncoderState(b)
+		instr.op(instr, state, unsafe.Pointer(&data))
+		if !bytes.Equal(boolResult, b.Bytes()) {
+			t.Errorf("bool enc instructions: expected % x got % x", boolResult, b.Bytes())
+		}
+	}
+
+	// int
+	{
+		b.Reset()
+		data := struct{ a int }{17}
+		instr := &encInstr{encInt, 6, 0, 0}
+		state := newEncoderState(b)
+		instr.op(instr, state, unsafe.Pointer(&data))
+		if !bytes.Equal(signedResult, b.Bytes()) {
+			t.Errorf("int enc instructions: expected % x got % x", signedResult, b.Bytes())
+		}
+	}
+
+	// uint
+	{
+		b.Reset()
+		data := struct{ a uint }{17}
+		instr := &encInstr{encUint, 6, 0, 0}
+		state := newEncoderState(b)
+		instr.op(instr, state, unsafe.Pointer(&data))
+		if !bytes.Equal(unsignedResult, b.Bytes()) {
+			t.Errorf("uint enc instructions: expected % x got % x", unsignedResult, b.Bytes())
+		}
+	}
+
+	// int8
+	{
+		b.Reset()
+		data := struct{ a int8 }{17}
+		instr := &encInstr{encInt8, 6, 0, 0}
+		state := newEncoderState(b)
+		instr.op(instr, state, unsafe.Pointer(&data))
+		if !bytes.Equal(signedResult, b.Bytes()) {
+			t.Errorf("int8 enc instructions: expected % x got % x", signedResult, b.Bytes())
+		}
+	}
+
+	// uint8
+	{
+		b.Reset()
+		data := struct{ a uint8 }{17}
+		instr := &encInstr{encUint8, 6, 0, 0}
+		state := newEncoderState(b)
+		instr.op(instr, state, unsafe.Pointer(&data))
+		if !bytes.Equal(unsignedResult, b.Bytes()) {
+			t.Errorf("uint8 enc instructions: expected % x got % x", unsignedResult, b.Bytes())
+		}
+	}
+
+	// int16
+	{
+		b.Reset()
+		data := struct{ a int16 }{17}
+		instr := &encInstr{encInt16, 6, 0, 0}
+		state := newEncoderState(b)
+		instr.op(instr, state, unsafe.Pointer(&data))
+		if !bytes.Equal(signedResult, b.Bytes()) {
+			t.Errorf("int16 enc instructions: expected % x got % x", signedResult, b.Bytes())
+		}
+	}
+
+	// uint16
+	{
+		b.Reset()
+		data := struct{ a uint16 }{17}
+		instr := &encInstr{encUint16, 6, 0, 0}
+		state := newEncoderState(b)
+		instr.op(instr, state, unsafe.Pointer(&data))
+		if !bytes.Equal(unsignedResult, b.Bytes()) {
+			t.Errorf("uint16 enc instructions: expected % x got % x", unsignedResult, b.Bytes())
+		}
+	}
+
+	// int32
+	{
+		b.Reset()
+		data := struct{ a int32 }{17}
+		instr := &encInstr{encInt32, 6, 0, 0}
+		state := newEncoderState(b)
+		instr.op(instr, state, unsafe.Pointer(&data))
+		if !bytes.Equal(signedResult, b.Bytes()) {
+			t.Errorf("int32 enc instructions: expected % x got % x", signedResult, b.Bytes())
+		}
+	}
+
+	// uint32
+	{
+		b.Reset()
+		data := struct{ a uint32 }{17}
+		instr := &encInstr{encUint32, 6, 0, 0}
+		state := newEncoderState(b)
+		instr.op(instr, state, unsafe.Pointer(&data))
+		if !bytes.Equal(unsignedResult, b.Bytes()) {
+			t.Errorf("uint32 enc instructions: expected % x got % x", unsignedResult, b.Bytes())
+		}
+	}
+
+	// int64
+	{
+		b.Reset()
+		data := struct{ a int64 }{17}
+		instr := &encInstr{encInt64, 6, 0, 0}
+		state := newEncoderState(b)
+		instr.op(instr, state, unsafe.Pointer(&data))
+		if !bytes.Equal(signedResult, b.Bytes()) {
+			t.Errorf("int64 enc instructions: expected % x got % x", signedResult, b.Bytes())
+		}
+	}
+
+	// uint64
+	{
+		b.Reset()
+		data := struct{ a uint64 }{17}
+		instr := &encInstr{encUint64, 6, 0, 0}
+		state := newEncoderState(b)
+		instr.op(instr, state, unsafe.Pointer(&data))
+		if !bytes.Equal(unsignedResult, b.Bytes()) {
+			t.Errorf("uint64 enc instructions: expected % x got % x", unsignedResult, b.Bytes())
+		}
+	}
+
+	// float32
+	{
+		b.Reset()
+		data := struct{ a float32 }{17}
+		instr := &encInstr{encFloat32, 6, 0, 0}
+		state := newEncoderState(b)
+		instr.op(instr, state, unsafe.Pointer(&data))
+		if !bytes.Equal(floatResult, b.Bytes()) {
+			t.Errorf("float32 enc instructions: expected % x got % x", floatResult, b.Bytes())
+		}
+	}
+
+	// float64
+	{
+		b.Reset()
+		data := struct{ a float64 }{17}
+		instr := &encInstr{encFloat64, 6, 0, 0}
+		state := newEncoderState(b)
+		instr.op(instr, state, unsafe.Pointer(&data))
+		if !bytes.Equal(floatResult, b.Bytes()) {
+			t.Errorf("float64 enc instructions: expected % x got % x", floatResult, b.Bytes())
+		}
+	}
+
+	// bytes == []uint8
+	{
+		b.Reset()
+		data := struct{ a []byte }{[]byte("hello")}
+		instr := &encInstr{encUint8Array, 6, 0, 0}
+		state := newEncoderState(b)
+		instr.op(instr, state, unsafe.Pointer(&data))
+		if !bytes.Equal(bytesResult, b.Bytes()) {
+			t.Errorf("bytes enc instructions: expected % x got % x", bytesResult, b.Bytes())
+		}
+	}
+
+	// string
+	{
+		b.Reset()
+		data := struct{ a string }{"hello"}
+		instr := &encInstr{encString, 6, 0, 0}
+		state := newEncoderState(b)
+		instr.op(instr, state, unsafe.Pointer(&data))
+		if !bytes.Equal(bytesResult, b.Bytes()) {
+			t.Errorf("string enc instructions: expected % x got % x", bytesResult, b.Bytes())
+		}
+	}
+}
+
+func execDec(typ string, instr *decInstr, state *decoderState, t *testing.T, p unsafe.Pointer) {
+	defer testError(t)
+	v := int(state.decodeUint())
+	if v+state.fieldnum != 6 {
+		t.Fatalf("decoding field number %d, got %d", 6, v+state.fieldnum)
+	}
+	instr.op(instr, state, decIndirect(p, instr.indir))
+	state.fieldnum = 6
+}
+
+func newDecodeStateFromData(data []byte) *decoderState {
+	b := bytes.NewBuffer(data)
+	state := newDecodeState(b)
+	state.fieldnum = -1
+	return state
+}
+
+// Test instruction execution for decoding.
+// Do not run the machine yet; instead do individual instructions crafted by hand.
+func TestScalarDecInstructions(t *testing.T) {
+	ovfl := errors.New("overflow")
+
+	// bool
+	{
+		var data struct {
+			a bool
+		}
+		instr := &decInstr{decBool, 6, 0, 0, ovfl}
+		state := newDecodeStateFromData(boolResult)
+		execDec("bool", instr, state, t, unsafe.Pointer(&data))
+		if data.a != true {
+			t.Errorf("bool a = %v not true", data.a)
+		}
+	}
+	// int
+	{
+		var data struct {
+			a int
+		}
+		instr := &decInstr{decOpTable[reflect.Int], 6, 0, 0, ovfl}
+		state := newDecodeStateFromData(signedResult)
+		execDec("int", instr, state, t, unsafe.Pointer(&data))
+		if data.a != 17 {
+			t.Errorf("int a = %v not 17", data.a)
+		}
+	}
+
+	// uint
+	{
+		var data struct {
+			a uint
+		}
+		instr := &decInstr{decOpTable[reflect.Uint], 6, 0, 0, ovfl}
+		state := newDecodeStateFromData(unsignedResult)
+		execDec("uint", instr, state, t, unsafe.Pointer(&data))
+		if data.a != 17 {
+			t.Errorf("uint a = %v not 17", data.a)
+		}
+	}
+
+	// int8
+	{
+		var data struct {
+			a int8
+		}
+		instr := &decInstr{decInt8, 6, 0, 0, ovfl}
+		state := newDecodeStateFromData(signedResult)
+		execDec("int8", instr, state, t, unsafe.Pointer(&data))
+		if data.a != 17 {
+			t.Errorf("int8 a = %v not 17", data.a)
+		}
+	}
+
+	// uint8
+	{
+		var data struct {
+			a uint8
+		}
+		instr := &decInstr{decUint8, 6, 0, 0, ovfl}
+		state := newDecodeStateFromData(unsignedResult)
+		execDec("uint8", instr, state, t, unsafe.Pointer(&data))
+		if data.a != 17 {
+			t.Errorf("uint8 a = %v not 17", data.a)
+		}
+	}
+
+	// int16
+	{
+		var data struct {
+			a int16
+		}
+		instr := &decInstr{decInt16, 6, 0, 0, ovfl}
+		state := newDecodeStateFromData(signedResult)
+		execDec("int16", instr, state, t, unsafe.Pointer(&data))
+		if data.a != 17 {
+			t.Errorf("int16 a = %v not 17", data.a)
+		}
+	}
+
+	// uint16
+	{
+		var data struct {
+			a uint16
+		}
+		instr := &decInstr{decUint16, 6, 0, 0, ovfl}
+		state := newDecodeStateFromData(unsignedResult)
+		execDec("uint16", instr, state, t, unsafe.Pointer(&data))
+		if data.a != 17 {
+			t.Errorf("uint16 a = %v not 17", data.a)
+		}
+	}
+
+	// int32
+	{
+		var data struct {
+			a int32
+		}
+		instr := &decInstr{decInt32, 6, 0, 0, ovfl}
+		state := newDecodeStateFromData(signedResult)
+		execDec("int32", instr, state, t, unsafe.Pointer(&data))
+		if data.a != 17 {
+			t.Errorf("int32 a = %v not 17", data.a)
+		}
+	}
+
+	// uint32
+	{
+		var data struct {
+			a uint32
+		}
+		instr := &decInstr{decUint32, 6, 0, 0, ovfl}
+		state := newDecodeStateFromData(unsignedResult)
+		execDec("uint32", instr, state, t, unsafe.Pointer(&data))
+		if data.a != 17 {
+			t.Errorf("uint32 a = %v not 17", data.a)
+		}
+	}
+
+	// uintptr
+	{
+		var data struct {
+			a uintptr
+		}
+		instr := &decInstr{decOpTable[reflect.Uintptr], 6, 0, 0, ovfl}
+		state := newDecodeStateFromData(unsignedResult)
+		execDec("uintptr", instr, state, t, unsafe.Pointer(&data))
+		if data.a != 17 {
+			t.Errorf("uintptr a = %v not 17", data.a)
+		}
+	}
+
+	// int64
+	{
+		var data struct {
+			a int64
+		}
+		instr := &decInstr{decInt64, 6, 0, 0, ovfl}
+		state := newDecodeStateFromData(signedResult)
+		execDec("int64", instr, state, t, unsafe.Pointer(&data))
+		if data.a != 17 {
+			t.Errorf("int64 a = %v not 17", data.a)
+		}
+	}
+
+	// uint64
+	{
+		var data struct {
+			a uint64
+		}
+		instr := &decInstr{decUint64, 6, 0, 0, ovfl}
+		state := newDecodeStateFromData(unsignedResult)
+		execDec("uint64", instr, state, t, unsafe.Pointer(&data))
+		if data.a != 17 {
+			t.Errorf("uint64 a = %v not 17", data.a)
+		}
+	}
+
+	// float32
+	{
+		var data struct {
+			a float32
+		}
+		instr := &decInstr{decFloat32, 6, 0, 0, ovfl}
+		state := newDecodeStateFromData(floatResult)
+		execDec("float32", instr, state, t, unsafe.Pointer(&data))
+		if data.a != 17 {
+			t.Errorf("float32 a = %v not 17", data.a)
+		}
+	}
+
+	// float64
+	{
+		var data struct {
+			a float64
+		}
+		instr := &decInstr{decFloat64, 6, 0, 0, ovfl}
+		state := newDecodeStateFromData(floatResult)
+		execDec("float64", instr, state, t, unsafe.Pointer(&data))
+		if data.a != 17 {
+			t.Errorf("float64 a = %v not 17", data.a)
+		}
+	}
+
+	// complex64
+	{
+		var data struct {
+			a complex64
+		}
+		instr := &decInstr{decOpTable[reflect.Complex64], 6, 0, 0, ovfl}
+		state := newDecodeStateFromData(complexResult)
+		execDec("complex", instr, state, t, unsafe.Pointer(&data))
+		if data.a != 17+19i {
+			t.Errorf("complex a = %v not 17+19i", data.a)
+		}
+	}
+
+	// complex128
+	{
+		var data struct {
+			a complex128
+		}
+		instr := &decInstr{decOpTable[reflect.Complex128], 6, 0, 0, ovfl}
+		state := newDecodeStateFromData(complexResult)
+		execDec("complex", instr, state, t, unsafe.Pointer(&data))
+		if data.a != 17+19i {
+			t.Errorf("complex a = %v not 17+19i", data.a)
+		}
+	}
+
+	// bytes == []uint8
+	{
+		var data struct {
+			a []byte
+		}
+		instr := &decInstr{decUint8Slice, 6, 0, 0, ovfl}
+		state := newDecodeStateFromData(bytesResult)
+		execDec("bytes", instr, state, t, unsafe.Pointer(&data))
+		if string(data.a) != "hello" {
+			t.Errorf(`bytes a = %q not "hello"`, string(data.a))
+		}
+	}
+
+	// string
+	{
+		var data struct {
+			a string
+		}
+		instr := &decInstr{decString, 6, 0, 0, ovfl}
+		state := newDecodeStateFromData(bytesResult)
+		execDec("bytes", instr, state, t, unsafe.Pointer(&data))
+		if data.a != "hello" {
+			t.Errorf(`bytes a = %q not "hello"`, data.a)
+		}
+	}
+}
+
+func TestEndToEnd(t *testing.T) {
+	type T2 struct {
+		T string
+	}
+	s1 := "string1"
+	s2 := "string2"
+	type T1 struct {
+		A, B, C  int
+		M        map[string]*float64
+		EmptyMap map[string]int // to check that we receive a non-nil map.
+		N        *[3]float64
+		Strs     *[2]string
+		Int64s   *[]int64
+		RI       complex64
+		S        string
+		Y        []byte
+		T        *T2
+	}
+	pi := 3.14159
+	e := 2.71828
+	t1 := &T1{
+		A:        17,
+		B:        18,
+		C:        -5,
+		M:        map[string]*float64{"pi": &pi, "e": &e},
+		EmptyMap: make(map[string]int),
+		N:        &[3]float64{1.5, 2.5, 3.5},
+		Strs:     &[2]string{s1, s2},
+		Int64s:   &[]int64{77, 89, 123412342134},
+		RI:       17 - 23i,
+		S:        "Now is the time",
+		Y:        []byte("hello, sailor"),
+		T:        &T2{"this is T2"},
+	}
+	b := new(bytes.Buffer)
+	err := NewEncoder(b).Encode(t1)
+	if err != nil {
+		t.Error("encode:", err)
+	}
+	var _t1 T1
+	err = NewDecoder(b).Decode(&_t1)
+	if err != nil {
+		t.Fatal("decode:", err)
+	}
+	if !reflect.DeepEqual(t1, &_t1) {
+		t.Errorf("encode expected %v got %v", *t1, _t1)
+	}
+	// Be absolutely sure the received map is non-nil.
+	if t1.EmptyMap == nil {
+		t.Errorf("nil map sent")
+	}
+	if _t1.EmptyMap == nil {
+		t.Errorf("nil map received")
+	}
+}
+
+func TestOverflow(t *testing.T) {
+	type inputT struct {
+		Maxi int64
+		Mini int64
+		Maxu uint64
+		Maxf float64
+		Minf float64
+		Maxc complex128
+		Minc complex128
+	}
+	var it inputT
+	var err error
+	b := new(bytes.Buffer)
+	enc := NewEncoder(b)
+	dec := NewDecoder(b)
+
+	// int8
+	b.Reset()
+	it = inputT{
+		Maxi: math.MaxInt8 + 1,
+	}
+	type outi8 struct {
+		Maxi int8
+		Mini int8
+	}
+	var o1 outi8
+	enc.Encode(it)
+	err = dec.Decode(&o1)
+	if err == nil || err.Error() != `value for "Maxi" out of range` {
+		t.Error("wrong overflow error for int8:", err)
+	}
+	it = inputT{
+		Mini: math.MinInt8 - 1,
+	}
+	b.Reset()
+	enc.Encode(it)
+	err = dec.Decode(&o1)
+	if err == nil || err.Error() != `value for "Mini" out of range` {
+		t.Error("wrong underflow error for int8:", err)
+	}
+
+	// int16
+	b.Reset()
+	it = inputT{
+		Maxi: math.MaxInt16 + 1,
+	}
+	type outi16 struct {
+		Maxi int16
+		Mini int16
+	}
+	var o2 outi16
+	enc.Encode(it)
+	err = dec.Decode(&o2)
+	if err == nil || err.Error() != `value for "Maxi" out of range` {
+		t.Error("wrong overflow error for int16:", err)
+	}
+	it = inputT{
+		Mini: math.MinInt16 - 1,
+	}
+	b.Reset()
+	enc.Encode(it)
+	err = dec.Decode(&o2)
+	if err == nil || err.Error() != `value for "Mini" out of range` {
+		t.Error("wrong underflow error for int16:", err)
+	}
+
+	// int32
+	b.Reset()
+	it = inputT{
+		Maxi: math.MaxInt32 + 1,
+	}
+	type outi32 struct {
+		Maxi int32
+		Mini int32
+	}
+	var o3 outi32
+	enc.Encode(it)
+	err = dec.Decode(&o3)
+	if err == nil || err.Error() != `value for "Maxi" out of range` {
+		t.Error("wrong overflow error for int32:", err)
+	}
+	it = inputT{
+		Mini: math.MinInt32 - 1,
+	}
+	b.Reset()
+	enc.Encode(it)
+	err = dec.Decode(&o3)
+	if err == nil || err.Error() != `value for "Mini" out of range` {
+		t.Error("wrong underflow error for int32:", err)
+	}
+
+	// uint8
+	b.Reset()
+	it = inputT{
+		Maxu: math.MaxUint8 + 1,
+	}
+	type outu8 struct {
+		Maxu uint8
+	}
+	var o4 outu8
+	enc.Encode(it)
+	err = dec.Decode(&o4)
+	if err == nil || err.Error() != `value for "Maxu" out of range` {
+		t.Error("wrong overflow error for uint8:", err)
+	}
+
+	// uint16
+	b.Reset()
+	it = inputT{
+		Maxu: math.MaxUint16 + 1,
+	}
+	type outu16 struct {
+		Maxu uint16
+	}
+	var o5 outu16
+	enc.Encode(it)
+	err = dec.Decode(&o5)
+	if err == nil || err.Error() != `value for "Maxu" out of range` {
+		t.Error("wrong overflow error for uint16:", err)
+	}
+
+	// uint32
+	b.Reset()
+	it = inputT{
+		Maxu: math.MaxUint32 + 1,
+	}
+	type outu32 struct {
+		Maxu uint32
+	}
+	var o6 outu32
+	enc.Encode(it)
+	err = dec.Decode(&o6)
+	if err == nil || err.Error() != `value for "Maxu" out of range` {
+		t.Error("wrong overflow error for uint32:", err)
+	}
+
+	// float32
+	b.Reset()
+	it = inputT{
+		Maxf: math.MaxFloat32 * 2,
+	}
+	type outf32 struct {
+		Maxf float32
+		Minf float32
+	}
+	var o7 outf32
+	enc.Encode(it)
+	err = dec.Decode(&o7)
+	if err == nil || err.Error() != `value for "Maxf" out of range` {
+		t.Error("wrong overflow error for float32:", err)
+	}
+
+	// complex64
+	b.Reset()
+	it = inputT{
+		Maxc: complex(math.MaxFloat32*2, math.MaxFloat32*2),
+	}
+	type outc64 struct {
+		Maxc complex64
+		Minc complex64
+	}
+	var o8 outc64
+	enc.Encode(it)
+	err = dec.Decode(&o8)
+	if err == nil || err.Error() != `value for "Maxc" out of range` {
+		t.Error("wrong overflow error for complex64:", err)
+	}
+}
+
+func TestNesting(t *testing.T) {
+	type RT struct {
+		A    string
+		Next *RT
+	}
+	rt := new(RT)
+	rt.A = "level1"
+	rt.Next = new(RT)
+	rt.Next.A = "level2"
+	b := new(bytes.Buffer)
+	NewEncoder(b).Encode(rt)
+	var drt RT
+	dec := NewDecoder(b)
+	err := dec.Decode(&drt)
+	if err != nil {
+		t.Fatal("decoder error:", err)
+	}
+	if drt.A != rt.A {
+		t.Errorf("nesting: encode expected %v got %v", *rt, drt)
+	}
+	if drt.Next == nil {
+		t.Errorf("nesting: recursion failed")
+	}
+	if drt.Next.A != rt.Next.A {
+		t.Errorf("nesting: encode expected %v got %v", *rt.Next, *drt.Next)
+	}
+}
+
+// These three structures have the same data with different indirections
+type T0 struct {
+	A int
+	B int
+	C int
+	D int
+}
+type T1 struct {
+	A int
+	B *int
+	C **int
+	D ***int
+}
+type T2 struct {
+	A ***int
+	B **int
+	C *int
+	D int
+}
+
+func TestAutoIndirection(t *testing.T) {
+	// First transfer t1 into t0
+	var t1 T1
+	t1.A = 17
+	t1.B = new(int)
+	*t1.B = 177
+	t1.C = new(*int)
+	*t1.C = new(int)
+	**t1.C = 1777
+	t1.D = new(**int)
+	*t1.D = new(*int)
+	**t1.D = new(int)
+	***t1.D = 17777
+	b := new(bytes.Buffer)
+	enc := NewEncoder(b)
+	enc.Encode(t1)
+	dec := NewDecoder(b)
+	var t0 T0
+	dec.Decode(&t0)
+	if t0.A != 17 || t0.B != 177 || t0.C != 1777 || t0.D != 17777 {
+		t.Errorf("t1->t0: expected {17 177 1777 17777}; got %v", t0)
+	}
+
+	// Now transfer t2 into t0
+	var t2 T2
+	t2.D = 17777
+	t2.C = new(int)
+	*t2.C = 1777
+	t2.B = new(*int)
+	*t2.B = new(int)
+	**t2.B = 177
+	t2.A = new(**int)
+	*t2.A = new(*int)
+	**t2.A = new(int)
+	***t2.A = 17
+	b.Reset()
+	enc.Encode(t2)
+	t0 = T0{}
+	dec.Decode(&t0)
+	if t0.A != 17 || t0.B != 177 || t0.C != 1777 || t0.D != 17777 {
+		t.Errorf("t2->t0 expected {17 177 1777 17777}; got %v", t0)
+	}
+
+	// Now transfer t0 into t1
+	t0 = T0{17, 177, 1777, 17777}
+	b.Reset()
+	enc.Encode(t0)
+	t1 = T1{}
+	dec.Decode(&t1)
+	if t1.A != 17 || *t1.B != 177 || **t1.C != 1777 || ***t1.D != 17777 {
+		t.Errorf("t0->t1 expected {17 177 1777 17777}; got {%d %d %d %d}", t1.A, *t1.B, **t1.C, ***t1.D)
+	}
+
+	// Now transfer t0 into t2
+	b.Reset()
+	enc.Encode(t0)
+	t2 = T2{}
+	dec.Decode(&t2)
+	if ***t2.A != 17 || **t2.B != 177 || *t2.C != 1777 || t2.D != 17777 {
+		t.Errorf("t0->t2 expected {17 177 1777 17777}; got {%d %d %d %d}", ***t2.A, **t2.B, *t2.C, t2.D)
+	}
+
+	// Now do t2 again but without pre-allocated pointers.
+	b.Reset()
+	enc.Encode(t0)
+	***t2.A = 0
+	**t2.B = 0
+	*t2.C = 0
+	t2.D = 0
+	dec.Decode(&t2)
+	if ***t2.A != 17 || **t2.B != 177 || *t2.C != 1777 || t2.D != 17777 {
+		t.Errorf("t0->t2 expected {17 177 1777 17777}; got {%d %d %d %d}", ***t2.A, **t2.B, *t2.C, t2.D)
+	}
+}
+
+type RT0 struct {
+	A int
+	B string
+	C float64
+}
+type RT1 struct {
+	C      float64
+	B      string
+	A      int
+	NotSet string
+}
+
+func TestReorderedFields(t *testing.T) {
+	var rt0 RT0
+	rt0.A = 17
+	rt0.B = "hello"
+	rt0.C = 3.14159
+	b := new(bytes.Buffer)
+	NewEncoder(b).Encode(rt0)
+	dec := NewDecoder(b)
+	var rt1 RT1
+	// Wire type is RT0, local type is RT1.
+	err := dec.Decode(&rt1)
+	if err != nil {
+		t.Fatal("decode error:", err)
+	}
+	if rt0.A != rt1.A || rt0.B != rt1.B || rt0.C != rt1.C {
+		t.Errorf("rt1->rt0: expected %v; got %v", rt0, rt1)
+	}
+}
+
+// Like an RT0 but with fields we'll ignore on the decode side.
+type IT0 struct {
+	A        int64
+	B        string
+	Ignore_d []int
+	Ignore_e [3]float64
+	Ignore_f bool
+	Ignore_g string
+	Ignore_h []byte
+	Ignore_i *RT1
+	Ignore_m map[string]int
+	C        float64
+}
+
+func TestIgnoredFields(t *testing.T) {
+	var it0 IT0
+	it0.A = 17
+	it0.B = "hello"
+	it0.C = 3.14159
+	it0.Ignore_d = []int{1, 2, 3}
+	it0.Ignore_e[0] = 1.0
+	it0.Ignore_e[1] = 2.0
+	it0.Ignore_e[2] = 3.0
+	it0.Ignore_f = true
+	it0.Ignore_g = "pay no attention"
+	it0.Ignore_h = []byte("to the curtain")
+	it0.Ignore_i = &RT1{3.1, "hi", 7, "hello"}
+	it0.Ignore_m = map[string]int{"one": 1, "two": 2}
+
+	b := new(bytes.Buffer)
+	NewEncoder(b).Encode(it0)
+	dec := NewDecoder(b)
+	var rt1 RT1
+	// Wire type is IT0, local type is RT1.
+	err := dec.Decode(&rt1)
+	if err != nil {
+		t.Error("error: ", err)
+	}
+	if int(it0.A) != rt1.A || it0.B != rt1.B || it0.C != rt1.C {
+		t.Errorf("rt0->rt1: expected %v; got %v", it0, rt1)
+	}
+}
+
+func TestBadRecursiveType(t *testing.T) {
+	type Rec ***Rec
+	var rec Rec
+	b := new(bytes.Buffer)
+	err := NewEncoder(b).Encode(&rec)
+	if err == nil {
+		t.Error("expected error; got none")
+	} else if strings.Index(err.Error(), "recursive") < 0 {
+		t.Error("expected recursive type error; got", err)
+	}
+	// Can't test decode easily because we can't encode one, so we can't pass one to a Decoder.
+}
+
+type Bad0 struct {
+	CH chan int
+	C  float64
+}
+
+func TestInvalidField(t *testing.T) {
+	var bad0 Bad0
+	bad0.CH = make(chan int)
+	b := new(bytes.Buffer)
+	dummyEncoder := new(Encoder) // sufficient for this purpose.
+	dummyEncoder.encode(b, reflect.ValueOf(&bad0), userType(reflect.TypeOf(&bad0)))
+	if err := dummyEncoder.err; err == nil {
+		t.Error("expected error; got none")
+	} else if strings.Index(err.Error(), "type") < 0 {
+		t.Error("expected type error; got", err)
+	}
+}
+
+type Indirect struct {
+	A ***[3]int
+	S ***[]int
+	M ****map[string]int
+}
+
+type Direct struct {
+	A [3]int
+	S []int
+	M map[string]int
+}
+
+func TestIndirectSliceMapArray(t *testing.T) {
+	// Marshal indirect, unmarshal to direct.
+	i := new(Indirect)
+	i.A = new(**[3]int)
+	*i.A = new(*[3]int)
+	**i.A = new([3]int)
+	***i.A = [3]int{1, 2, 3}
+	i.S = new(**[]int)
+	*i.S = new(*[]int)
+	**i.S = new([]int)
+	***i.S = []int{4, 5, 6}
+	i.M = new(***map[string]int)
+	*i.M = new(**map[string]int)
+	**i.M = new(*map[string]int)
+	***i.M = new(map[string]int)
+	****i.M = map[string]int{"one": 1, "two": 2, "three": 3}
+	b := new(bytes.Buffer)
+	NewEncoder(b).Encode(i)
+	dec := NewDecoder(b)
+	var d Direct
+	err := dec.Decode(&d)
+	if err != nil {
+		t.Error("error: ", err)
+	}
+	if len(d.A) != 3 || d.A[0] != 1 || d.A[1] != 2 || d.A[2] != 3 {
+		t.Errorf("indirect to direct: d.A is %v not %v", d.A, ***i.A)
+	}
+	if len(d.S) != 3 || d.S[0] != 4 || d.S[1] != 5 || d.S[2] != 6 {
+		t.Errorf("indirect to direct: d.S is %v not %v", d.S, ***i.S)
+	}
+	if len(d.M) != 3 || d.M["one"] != 1 || d.M["two"] != 2 || d.M["three"] != 3 {
+		t.Errorf("indirect to direct: d.M is %v not %v", d.M, ***i.M)
+	}
+	// Marshal direct, unmarshal to indirect.
+	d.A = [3]int{11, 22, 33}
+	d.S = []int{44, 55, 66}
+	d.M = map[string]int{"four": 4, "five": 5, "six": 6}
+	i = new(Indirect)
+	b.Reset()
+	NewEncoder(b).Encode(d)
+	dec = NewDecoder(b)
+	err = dec.Decode(&i)
+	if err != nil {
+		t.Fatal("error: ", err)
+	}
+	if len(***i.A) != 3 || (***i.A)[0] != 11 || (***i.A)[1] != 22 || (***i.A)[2] != 33 {
+		t.Errorf("direct to indirect: ***i.A is %v not %v", ***i.A, d.A)
+	}
+	if len(***i.S) != 3 || (***i.S)[0] != 44 || (***i.S)[1] != 55 || (***i.S)[2] != 66 {
+		t.Errorf("direct to indirect: ***i.S is %v not %v", ***i.S, ***i.S)
+	}
+	if len(****i.M) != 3 || (****i.M)["four"] != 4 || (****i.M)["five"] != 5 || (****i.M)["six"] != 6 {
+		t.Errorf("direct to indirect: ****i.M is %v not %v", ****i.M, d.M)
+	}
+}
+
+// An interface with several implementations
+type Squarer interface {
+	Square() int
+}
+
+type Int int
+
+func (i Int) Square() int {
+	return int(i * i)
+}
+
+type Float float64
+
+func (f Float) Square() int {
+	return int(f * f)
+}
+
+type Vector []int
+
+func (v Vector) Square() int {
+	sum := 0
+	for _, x := range v {
+		sum += x * x
+	}
+	return sum
+}
+
+type Point struct {
+	X, Y int
+}
+
+func (p Point) Square() int {
+	return p.X*p.X + p.Y*p.Y
+}
+
+// A struct with interfaces in it.
+type InterfaceItem struct {
+	I             int
+	Sq1, Sq2, Sq3 Squarer
+	F             float64
+	Sq            []Squarer
+}
+
+// The same struct without interfaces
+type NoInterfaceItem struct {
+	I int
+	F float64
+}
+
+func TestInterface(t *testing.T) {
+	iVal := Int(3)
+	fVal := Float(5)
+	// Sending a Vector will require that the receiver define a type in the middle of
+	// receiving the value for item2.
+	vVal := Vector{1, 2, 3}
+	b := new(bytes.Buffer)
+	item1 := &InterfaceItem{1, iVal, fVal, vVal, 11.5, []Squarer{iVal, fVal, nil, vVal}}
+	// Register the types.
+	Register(Int(0))
+	Register(Float(0))
+	Register(Vector{})
+	err := NewEncoder(b).Encode(item1)
+	if err != nil {
+		t.Error("expected no encode error; got", err)
+	}
+
+	item2 := InterfaceItem{}
+	err = NewDecoder(b).Decode(&item2)
+	if err != nil {
+		t.Fatal("decode:", err)
+	}
+	if item2.I != item1.I {
+		t.Error("normal int did not decode correctly")
+	}
+	if item2.Sq1 == nil || item2.Sq1.Square() != iVal.Square() {
+		t.Error("Int did not decode correctly")
+	}
+	if item2.Sq2 == nil || item2.Sq2.Square() != fVal.Square() {
+		t.Error("Float did not decode correctly")
+	}
+	if item2.Sq3 == nil || item2.Sq3.Square() != vVal.Square() {
+		t.Error("Vector did not decode correctly")
+	}
+	if item2.F != item1.F {
+		t.Error("normal float did not decode correctly")
+	}
+	// Now check that we received a slice of Squarers correctly, including a nil element
+	if len(item1.Sq) != len(item2.Sq) {
+		t.Fatalf("[]Squarer length wrong: got %d; expected %d", len(item2.Sq), len(item1.Sq))
+	}
+	for i, v1 := range item1.Sq {
+		v2 := item2.Sq[i]
+		if v1 == nil || v2 == nil {
+			if v1 != nil || v2 != nil {
+				t.Errorf("item %d inconsistent nils", i)
+			}
+			continue
+			if v1.Square() != v2.Square() {
+				t.Errorf("item %d inconsistent values: %v %v", i, v1, v2)
+			}
+		}
+	}
+}
+
+// A struct with all basic types, stored in interfaces.
+type BasicInterfaceItem struct {
+	Int, Int8, Int16, Int32, Int64      interface{}
+	Uint, Uint8, Uint16, Uint32, Uint64 interface{}
+	Float32, Float64                    interface{}
+	Complex64, Complex128               interface{}
+	Bool                                interface{}
+	String                              interface{}
+	Bytes                               interface{}
+}
+
+func TestInterfaceBasic(t *testing.T) {
+	b := new(bytes.Buffer)
+	item1 := &BasicInterfaceItem{
+		int(1), int8(1), int16(1), int32(1), int64(1),
+		uint(1), uint8(1), uint16(1), uint32(1), uint64(1),
+		float32(1), 1.0,
+		complex64(1i), complex128(1i),
+		true,
+		"hello",
+		[]byte("sailor"),
+	}
+	err := NewEncoder(b).Encode(item1)
+	if err != nil {
+		t.Error("expected no encode error; got", err)
+	}
+
+	item2 := &BasicInterfaceItem{}
+	err = NewDecoder(b).Decode(&item2)
+	if err != nil {
+		t.Fatal("decode:", err)
+	}
+	if !reflect.DeepEqual(item1, item2) {
+		t.Errorf("encode expected %v got %v", item1, item2)
+	}
+	// Hand check a couple for correct types.
+	if v, ok := item2.Bool.(bool); !ok || !v {
+		t.Error("boolean should be true")
+	}
+	if v, ok := item2.String.(string); !ok || v != item1.String.(string) {
+		t.Errorf("string should be %v is %v", item1.String, v)
+	}
+}
+
+type String string
+
+type PtrInterfaceItem struct {
+	Str1 interface{} // basic
+	Str2 interface{} // derived
+}
+
+// We'll send pointers; should receive values.
+// Also check that we can register T but send *T.
+func TestInterfacePointer(t *testing.T) {
+	b := new(bytes.Buffer)
+	str1 := "howdy"
+	str2 := String("kiddo")
+	item1 := &PtrInterfaceItem{
+		&str1,
+		&str2,
+	}
+	// Register the type.
+	Register(str2)
+	err := NewEncoder(b).Encode(item1)
+	if err != nil {
+		t.Error("expected no encode error; got", err)
+	}
+
+	item2 := &PtrInterfaceItem{}
+	err = NewDecoder(b).Decode(&item2)
+	if err != nil {
+		t.Fatal("decode:", err)
+	}
+	// Hand test for correct types and values.
+	if v, ok := item2.Str1.(string); !ok || v != str1 {
+		t.Errorf("basic string failed: %q should be %q", v, str1)
+	}
+	if v, ok := item2.Str2.(String); !ok || v != str2 {
+		t.Errorf("derived type String failed: %q should be %q", v, str2)
+	}
+}
+
+func TestIgnoreInterface(t *testing.T) {
+	iVal := Int(3)
+	fVal := Float(5)
+	// Sending a Point will require that the receiver define a type in the middle of
+	// receiving the value for item2.
+	pVal := Point{2, 3}
+	b := new(bytes.Buffer)
+	item1 := &InterfaceItem{1, iVal, fVal, pVal, 11.5, nil}
+	// Register the types.
+	Register(Int(0))
+	Register(Float(0))
+	Register(Point{})
+	err := NewEncoder(b).Encode(item1)
+	if err != nil {
+		t.Error("expected no encode error; got", err)
+	}
+
+	item2 := NoInterfaceItem{}
+	err = NewDecoder(b).Decode(&item2)
+	if err != nil {
+		t.Fatal("decode:", err)
+	}
+	if item2.I != item1.I {
+		t.Error("normal int did not decode correctly")
+	}
+	if item2.F != item2.F {
+		t.Error("normal float did not decode correctly")
+	}
+}
+
+type U struct {
+	A int
+	B string
+	c float64
+	D uint
+}
+
+func TestUnexportedFields(t *testing.T) {
+	var u0 U
+	u0.A = 17
+	u0.B = "hello"
+	u0.c = 3.14159
+	u0.D = 23
+	b := new(bytes.Buffer)
+	NewEncoder(b).Encode(u0)
+	dec := NewDecoder(b)
+	var u1 U
+	u1.c = 1234.
+	err := dec.Decode(&u1)
+	if err != nil {
+		t.Fatal("decode error:", err)
+	}
+	if u0.A != u0.A || u0.B != u1.B || u0.D != u1.D {
+		t.Errorf("u1->u0: expected %v; got %v", u0, u1)
+	}
+	if u1.c != 1234. {
+		t.Error("u1.c modified")
+	}
+}
+
+var singletons = []interface{}{
+	true,
+	7,
+	3.2,
+	"hello",
+	[3]int{11, 22, 33},
+	[]float32{0.5, 0.25, 0.125},
+	map[string]int{"one": 1, "two": 2},
+}
+
+func TestDebugSingleton(t *testing.T) {
+	if debugFunc == nil {
+		return
+	}
+	b := new(bytes.Buffer)
+	// Accumulate a number of values and print them out all at once.
+	for _, x := range singletons {
+		err := NewEncoder(b).Encode(x)
+		if err != nil {
+			t.Fatal("encode:", err)
+		}
+	}
+	debugFunc(b)
+}
+
+// A type that won't be defined in the gob until we send it in an interface value.
+type OnTheFly struct {
+	A int
+}
+
+type DT struct {
+	//	X OnTheFly
+	A     int
+	B     string
+	C     float64
+	I     interface{}
+	J     interface{}
+	I_nil interface{}
+	M     map[string]int
+	T     [3]int
+	S     []string
+}
+
+func TestDebugStruct(t *testing.T) {
+	if debugFunc == nil {
+		return
+	}
+	Register(OnTheFly{})
+	var dt DT
+	dt.A = 17
+	dt.B = "hello"
+	dt.C = 3.14159
+	dt.I = 271828
+	dt.J = OnTheFly{3}
+	dt.I_nil = nil
+	dt.M = map[string]int{"one": 1, "two": 2}
+	dt.T = [3]int{11, 22, 33}
+	dt.S = []string{"hi", "joe"}
+	b := new(bytes.Buffer)
+	err := NewEncoder(b).Encode(dt)
+	if err != nil {
+		t.Fatal("encode:", err)
+	}
+	debugBuffer := bytes.NewBuffer(b.Bytes())
+	dt2 := &DT{}
+	err = NewDecoder(b).Decode(&dt2)
+	if err != nil {
+		t.Error("decode:", err)
+	}
+	debugFunc(debugBuffer)
+}
diff --git a/libgo/go/encoding/gob/debug.go b/libgo/go/encoding/gob/debug.go
new file mode 100644
index 00000000000..b21c7fa0b2b
--- /dev/null
+++ b/libgo/go/encoding/gob/debug.go
@@ -0,0 +1,687 @@
+package gob
+
+// This file is not normally included in the gob package.  Used only for debugging the package itself.
+// Add debug.go to the files listed in the Makefile to add Debug to the gob package.
+// Except for reading uints, it is an implementation of a reader that is independent of
+// the one implemented by Decoder.
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"os"
+	"strings"
+	"sync"
+)
+
+var dumpBytes = false // If true, print the remaining bytes in the input buffer at each item.
+
+// Init installs the debugging facility. If this file is not compiled in the
+// package, the tests in codec_test.go are no-ops.
+func init() {
+	debugFunc = Debug
+}
+
+var (
+	blanks = bytes.Repeat([]byte{' '}, 3*10)
+	empty  = []byte(": <empty>\n")
+	tabs   = strings.Repeat("\t", 100)
+)
+
+// tab indents itself when printed.
+type tab int
+
+func (t tab) String() string {
+	n := int(t)
+	if n > len(tabs) {
+		n = len(tabs)
+	}
+	return tabs[0:n]
+}
+
+func (t tab) print() {
+	fmt.Fprint(os.Stderr, t)
+}
+
+// A peekReader wraps an io.Reader, allowing one to peek ahead to see
+// what's coming without stealing the data from the client of the Reader.
+type peekReader struct {
+	r    io.Reader
+	data []byte // read-ahead data
+}
+
+// newPeekReader returns a peekReader that wraps r.
+func newPeekReader(r io.Reader) *peekReader {
+	return &peekReader{r: r}
+}
+
+// Read is the usual method. It will first take data that has been read ahead.
+func (p *peekReader) Read(b []byte) (n int, err error) {
+	if len(p.data) == 0 {
+		return p.r.Read(b)
+	}
+	// Satisfy what's possible from the read-ahead data.
+	n = copy(b, p.data)
+	// Move data down to beginning of slice, to avoid endless growth
+	copy(p.data, p.data[n:])
+	p.data = p.data[:len(p.data)-n]
+	return
+}
+
+// peek returns as many bytes as possible from the unread
+// portion of the stream, up to the length of b.
+func (p *peekReader) peek(b []byte) (n int, err error) {
+	if len(p.data) > 0 {
+		n = copy(b, p.data)
+		if n == len(b) {
+			return
+		}
+		b = b[n:]
+	}
+	if len(b) == 0 {
+		return
+	}
+	m, e := io.ReadFull(p.r, b)
+	if m > 0 {
+		p.data = append(p.data, b[:m]...)
+	}
+	n += m
+	if e == io.ErrUnexpectedEOF {
+		// That means m > 0 but we reached EOF. If we got data
+		// we won't complain about not being able to peek enough.
+		if n > 0 {
+			e = nil
+		} else {
+			e = io.EOF
+		}
+	}
+	return n, e
+}
+
+type debugger struct {
+	mutex          sync.Mutex
+	remain         int  // the number of bytes known to remain in the input
+	remainingKnown bool // the value of 'remain' is valid
+	r              *peekReader
+	wireType       map[typeId]*wireType
+	tmp            []byte // scratch space for decoding uints.
+}
+
+// dump prints the next nBytes of the input.
+// It arranges to print the output aligned from call to
+// call, to make it easy to see what has been consumed.
+func (deb *debugger) dump(format string, args ...interface{}) {
+	if !dumpBytes {
+		return
+	}
+	fmt.Fprintf(os.Stderr, format+" ", args...)
+	if !deb.remainingKnown {
+		return
+	}
+	if deb.remain < 0 {
+		fmt.Fprintf(os.Stderr, "remaining byte count is negative! %d\n", deb.remain)
+		return
+	}
+	data := make([]byte, deb.remain)
+	n, _ := deb.r.peek(data)
+	if n == 0 {
+		os.Stderr.Write(empty)
+		return
+	}
+	b := new(bytes.Buffer)
+	fmt.Fprintf(b, "[%d]{\n", deb.remain)
+	// Blanks until first byte
+	lineLength := 0
+	if n := len(data); n%10 != 0 {
+		lineLength = 10 - n%10
+		fmt.Fprintf(b, "\t%s", blanks[:lineLength*3])
+	}
+	// 10 bytes per line
+	for len(data) > 0 {
+		if lineLength == 0 {
+			fmt.Fprint(b, "\t")
+		}
+		m := 10 - lineLength
+		lineLength = 0
+		if m > len(data) {
+			m = len(data)
+		}
+		fmt.Fprintf(b, "% x\n", data[:m])
+		data = data[m:]
+	}
+	fmt.Fprint(b, "}\n")
+	os.Stderr.Write(b.Bytes())
+}
+
+// Debug prints a human-readable representation of the gob data read from r.
+// It is a no-op unless debugging was enabled when the package was built.
+func Debug(r io.Reader) {
+	err := debug(r)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "gob debug: %s\n", err)
+	}
+}
+
+// debug implements Debug, but catches panics and returns
+// them as errors to be printed by Debug.
+func debug(r io.Reader) (err error) {
+	defer catchError(&err)
+	fmt.Fprintln(os.Stderr, "Start of debugging")
+	deb := &debugger{
+		r:        newPeekReader(r),
+		wireType: make(map[typeId]*wireType),
+		tmp:      make([]byte, 16),
+	}
+	if b, ok := r.(*bytes.Buffer); ok {
+		deb.remain = b.Len()
+		deb.remainingKnown = true
+	}
+	deb.gobStream()
+	return
+}
+
+// note that we've consumed some bytes
+func (deb *debugger) consumed(n int) {
+	if deb.remainingKnown {
+		deb.remain -= n
+	}
+}
+
+// int64 decodes and returns the next integer, which must be present.
+// Don't call this if you could be at EOF.
+func (deb *debugger) int64() int64 {
+	return toInt(deb.uint64())
+}
+
+// uint64 returns and decodes the next unsigned integer, which must be present.
+// Don't call this if you could be at EOF.
+// TODO: handle errors better.
+func (deb *debugger) uint64() uint64 {
+	n, w, err := decodeUintReader(deb.r, deb.tmp)
+	if err != nil {
+		errorf("debug: read error: %s", err)
+	}
+	deb.consumed(w)
+	return n
+}
+
+// GobStream:
+//	DelimitedMessage* (until EOF)
+func (deb *debugger) gobStream() {
+	// Make sure we're single-threaded through here.
+	deb.mutex.Lock()
+	defer deb.mutex.Unlock()
+
+	for deb.delimitedMessage(0) {
+	}
+}
+
+// DelimitedMessage:
+//	uint(lengthOfMessage) Message
+func (deb *debugger) delimitedMessage(indent tab) bool {
+	for {
+		n := deb.loadBlock(true)
+		if n < 0 {
+			return false
+		}
+		deb.dump("Delimited message of length %d", n)
+		deb.message(indent)
+	}
+	return true
+}
+
+// loadBlock preps us to read a message
+// of the length specified next in the input. It returns
+// the length of the block. The argument tells whether
+// an EOF is acceptable now.  If it is and one is found,
+// the return value is negative.
+func (deb *debugger) loadBlock(eofOK bool) int {
+	n64, w, err := decodeUintReader(deb.r, deb.tmp) // deb.uint64 will error at EOF
+	if err != nil {
+		if eofOK && err == io.EOF {
+			return -1
+		}
+		errorf("debug: unexpected error: %s", err)
+	}
+	deb.consumed(w)
+	n := int(n64)
+	if n < 0 {
+		errorf("huge value for message length: %d", n64)
+	}
+	return int(n)
+}
+
+// Message:
+//	TypeSequence TypedValue
+// TypeSequence
+//	(TypeDefinition DelimitedTypeDefinition*)?
+// DelimitedTypeDefinition:
+//	uint(lengthOfTypeDefinition) TypeDefinition
+// TypedValue:
+//	int(typeId) Value
+func (deb *debugger) message(indent tab) bool {
+	for {
+		// Convert the uint64 to a signed integer typeId
+		uid := deb.int64()
+		id := typeId(uid)
+		deb.dump("type id=%d", id)
+		if id < 0 {
+			deb.typeDefinition(indent, -id)
+			n := deb.loadBlock(false)
+			deb.dump("Message of length %d", n)
+			continue
+		} else {
+			deb.value(indent, id)
+			break
+		}
+	}
+	return true
+}
+
+// Helper methods to make it easy to scan a type descriptor.
+
+// common returns the CommonType at the input point.
+func (deb *debugger) common() CommonType {
+	fieldNum := -1
+	name := ""
+	id := typeId(0)
+	for {
+		delta := deb.delta(-1)
+		if delta == 0 {
+			break
+		}
+		fieldNum += delta
+		switch fieldNum {
+		case 0:
+			name = deb.string()
+		case 1:
+			// Id typeId
+			id = deb.typeId()
+		default:
+			errorf("corrupted CommonType")
+		}
+	}
+	return CommonType{name, id}
+}
+
+// uint returns the unsigned int at the input point, as a uint (not uint64).
+func (deb *debugger) uint() uint {
+	return uint(deb.uint64())
+}
+
+// int returns the signed int at the input point, as an int (not int64).
+func (deb *debugger) int() int {
+	return int(deb.int64())
+}
+
+// typeId returns the type id at the input point.
+func (deb *debugger) typeId() typeId {
+	return typeId(deb.int64())
+}
+
+// string returns the string at the input point.
+func (deb *debugger) string() string {
+	x := int(deb.uint64())
+	b := make([]byte, x)
+	nb, _ := deb.r.Read(b)
+	if nb != x {
+		errorf("corrupted type")
+	}
+	deb.consumed(nb)
+	return string(b)
+}
+
+// delta returns the field delta at the input point.  The expect argument,
+// if non-negative, identifies what the value should be.
+func (deb *debugger) delta(expect int) int {
+	delta := int(deb.uint64())
+	if delta < 0 || (expect >= 0 && delta != expect) {
+		errorf("decode: corrupted type: delta %d expected %d", delta, expect)
+	}
+	return delta
+}
+
+// TypeDefinition:
+//	[int(-typeId) (already read)] encodingOfWireType
+func (deb *debugger) typeDefinition(indent tab, id typeId) {
+	deb.dump("type definition for id %d", id)
+	// Encoding is of a wireType. Decode the structure as usual
+	fieldNum := -1
+	wire := new(wireType)
+	// A wireType defines a single field.
+	delta := deb.delta(-1)
+	fieldNum += delta
+	switch fieldNum {
+	case 0: // array type, one field of {{Common}, elem, length}
+		// Field number 0 is CommonType
+		deb.delta(1)
+		com := deb.common()
+		// Field number 1 is type Id of elem
+		deb.delta(1)
+		id := deb.typeId()
+		// Field number 3 is length
+		deb.delta(1)
+		length := deb.int()
+		wire.ArrayT = &arrayType{com, id, length}
+
+	case 1: // slice type, one field of {{Common}, elem}
+		// Field number 0 is CommonType
+		deb.delta(1)
+		com := deb.common()
+		// Field number 1 is type Id of elem
+		deb.delta(1)
+		id := deb.typeId()
+		wire.SliceT = &sliceType{com, id}
+
+	case 2: // struct type, one field of {{Common}, []fieldType}
+		// Field number 0 is CommonType
+		deb.delta(1)
+		com := deb.common()
+		// Field number 1 is slice of FieldType
+		deb.delta(1)
+		numField := int(deb.uint())
+		field := make([]*fieldType, numField)
+		for i := 0; i < numField; i++ {
+			field[i] = new(fieldType)
+			deb.delta(1) // field 0 of fieldType: name
+			field[i].Name = deb.string()
+			deb.delta(1) // field 1 of fieldType: id
+			field[i].Id = deb.typeId()
+			deb.delta(0) // end of fieldType
+		}
+		wire.StructT = &structType{com, field}
+
+	case 3: // map type, one field of {{Common}, key, elem}
+		// Field number 0 is CommonType
+		deb.delta(1)
+		com := deb.common()
+		// Field number 1 is type Id of key
+		deb.delta(1)
+		keyId := deb.typeId()
+		// Field number 2 is type Id of elem
+		deb.delta(1)
+		elemId := deb.typeId()
+		wire.MapT = &mapType{com, keyId, elemId}
+	case 4: // GobEncoder type, one field of {{Common}}
+		// Field number 0 is CommonType
+		deb.delta(1)
+		com := deb.common()
+		wire.GobEncoderT = &gobEncoderType{com}
+	default:
+		errorf("bad field in type %d", fieldNum)
+	}
+	deb.printWireType(indent, wire)
+	deb.delta(0) // end inner type (arrayType, etc.)
+	deb.delta(0) // end wireType
+	// Remember we've seen this type.
+	deb.wireType[id] = wire
+}
+
+// Value:
+//	SingletonValue | StructValue
+func (deb *debugger) value(indent tab, id typeId) {
+	wire, ok := deb.wireType[id]
+	if ok && wire.StructT != nil {
+		deb.structValue(indent, id)
+	} else {
+		deb.singletonValue(indent, id)
+	}
+}
+
+// SingletonValue:
+//	uint(0) FieldValue
+func (deb *debugger) singletonValue(indent tab, id typeId) {
+	deb.dump("Singleton value")
+	// is it a builtin type?
+	wire := deb.wireType[id]
+	_, ok := builtinIdToType[id]
+	if !ok && wire == nil {
+		errorf("type id %d not defined", id)
+	}
+	m := deb.uint64()
+	if m != 0 {
+		errorf("expected zero; got %d", m)
+	}
+	deb.fieldValue(indent, id)
+}
+
+// InterfaceValue:
+//	NilInterfaceValue | NonNilInterfaceValue
+func (deb *debugger) interfaceValue(indent tab) {
+	deb.dump("Start of interface value")
+	if nameLen := deb.uint64(); nameLen == 0 {
+		deb.nilInterfaceValue(indent)
+	} else {
+		deb.nonNilInterfaceValue(indent, int(nameLen))
+	}
+}
+
+// NilInterfaceValue:
+//	uint(0) [already read]
+func (deb *debugger) nilInterfaceValue(indent tab) int {
+	fmt.Fprintf(os.Stderr, "%snil interface\n", indent)
+	return 0
+}
+
+// NonNilInterfaceValue:
+//	ConcreteTypeName TypeSequence InterfaceContents
+// ConcreteTypeName:
+//	uint(lengthOfName) [already read=n] name
+// InterfaceContents:
+//	int(concreteTypeId) DelimitedValue
+// DelimitedValue:
+//	uint(length) Value
+func (deb *debugger) nonNilInterfaceValue(indent tab, nameLen int) {
+	// ConcreteTypeName
+	b := make([]byte, nameLen)
+	deb.r.Read(b) // TODO: CHECK THESE READS!!
+	deb.consumed(nameLen)
+	name := string(b)
+
+	for {
+		id := deb.typeId()
+		if id < 0 {
+			deb.typeDefinition(indent, -id)
+			n := deb.loadBlock(false)
+			deb.dump("Nested message of length %d", n)
+		} else {
+			// DelimitedValue
+			x := deb.uint64() // in case we want to ignore the value; we don't.
+			fmt.Fprintf(os.Stderr, "%sinterface value, type %q id=%d; valueLength %d\n", indent, name, id, x)
+			deb.value(indent, id)
+			break
+		}
+	}
+}
+
+// printCommonType prints a common type; used by printWireType.
+func (deb *debugger) printCommonType(indent tab, kind string, common *CommonType) {
+	indent.print()
+	fmt.Fprintf(os.Stderr, "%s %q id=%d\n", kind, common.Name, common.Id)
+}
+
+// printWireType prints the contents of a wireType.
+func (deb *debugger) printWireType(indent tab, wire *wireType) {
+	fmt.Fprintf(os.Stderr, "%stype definition {\n", indent)
+	indent++
+	switch {
+	case wire.ArrayT != nil:
+		deb.printCommonType(indent, "array", &wire.ArrayT.CommonType)
+		fmt.Fprintf(os.Stderr, "%slen %d\n", indent+1, wire.ArrayT.Len)
+		fmt.Fprintf(os.Stderr, "%selemid %d\n", indent+1, wire.ArrayT.Elem)
+	case wire.MapT != nil:
+		deb.printCommonType(indent, "map", &wire.MapT.CommonType)
+		fmt.Fprintf(os.Stderr, "%skey id=%d\n", indent+1, wire.MapT.Key)
+		fmt.Fprintf(os.Stderr, "%selem id=%d\n", indent+1, wire.MapT.Elem)
+	case wire.SliceT != nil:
+		deb.printCommonType(indent, "slice", &wire.SliceT.CommonType)
+		fmt.Fprintf(os.Stderr, "%selem id=%d\n", indent+1, wire.SliceT.Elem)
+	case wire.StructT != nil:
+		deb.printCommonType(indent, "struct", &wire.StructT.CommonType)
+		for i, field := range wire.StructT.Field {
+			fmt.Fprintf(os.Stderr, "%sfield %d:\t%s\tid=%d\n", indent+1, i, field.Name, field.Id)
+		}
+	case wire.GobEncoderT != nil:
+		deb.printCommonType(indent, "GobEncoder", &wire.GobEncoderT.CommonType)
+	}
+	indent--
+	fmt.Fprintf(os.Stderr, "%s}\n", indent)
+}
+
+// fieldValue prints a value of any type, such as a struct field.
+// FieldValue:
+//	builtinValue | ArrayValue | MapValue | SliceValue | StructValue | InterfaceValue
+func (deb *debugger) fieldValue(indent tab, id typeId) {
+	_, ok := builtinIdToType[id]
+	if ok {
+		if id == tInterface {
+			deb.interfaceValue(indent)
+		} else {
+			deb.printBuiltin(indent, id)
+		}
+		return
+	}
+	wire, ok := deb.wireType[id]
+	if !ok {
+		errorf("type id %d not defined", id)
+	}
+	switch {
+	case wire.ArrayT != nil:
+		deb.arrayValue(indent, wire)
+	case wire.MapT != nil:
+		deb.mapValue(indent, wire)
+	case wire.SliceT != nil:
+		deb.sliceValue(indent, wire)
+	case wire.StructT != nil:
+		deb.structValue(indent, id)
+	case wire.GobEncoderT != nil:
+		deb.gobEncoderValue(indent, id)
+	default:
+		panic("bad wire type for field")
+	}
+}
+
+// printBuiltin prints a value not of a fundamental type, that is,
+// one whose type is known to gobs at bootstrap time.
+func (deb *debugger) printBuiltin(indent tab, id typeId) {
+	switch id {
+	case tBool:
+		x := deb.int64()
+		if x == 0 {
+			fmt.Fprintf(os.Stderr, "%sfalse\n", indent)
+		} else {
+			fmt.Fprintf(os.Stderr, "%strue\n", indent)
+		}
+	case tInt:
+		x := deb.int64()
+		fmt.Fprintf(os.Stderr, "%s%d\n", indent, x)
+	case tUint:
+		x := deb.int64()
+		fmt.Fprintf(os.Stderr, "%s%d\n", indent, x)
+	case tFloat:
+		x := deb.uint64()
+		fmt.Fprintf(os.Stderr, "%s%g\n", indent, floatFromBits(x))
+	case tComplex:
+		r := deb.uint64()
+		i := deb.uint64()
+		fmt.Fprintf(os.Stderr, "%s%g+%gi\n", indent, floatFromBits(r), floatFromBits(i))
+	case tBytes:
+		x := int(deb.uint64())
+		b := make([]byte, x)
+		deb.r.Read(b)
+		deb.consumed(x)
+		fmt.Fprintf(os.Stderr, "%s{% x}=%q\n", indent, b, b)
+	case tString:
+		x := int(deb.uint64())
+		b := make([]byte, x)
+		deb.r.Read(b)
+		deb.consumed(x)
+		fmt.Fprintf(os.Stderr, "%s%q\n", indent, b)
+	default:
+		panic("unknown builtin")
+	}
+}
+
+// ArrayValue:
+//	uint(n) FieldValue*n
+func (deb *debugger) arrayValue(indent tab, wire *wireType) {
+	elemId := wire.ArrayT.Elem
+	u := deb.uint64()
+	length := int(u)
+	for i := 0; i < length; i++ {
+		deb.fieldValue(indent, elemId)
+	}
+	if length != wire.ArrayT.Len {
+		fmt.Fprintf(os.Stderr, "%s(wrong length for array: %d should be %d)\n", indent, length, wire.ArrayT.Len)
+	}
+}
+
+// MapValue:
+//	uint(n) (FieldValue FieldValue)*n  [n (key, value) pairs]
+func (deb *debugger) mapValue(indent tab, wire *wireType) {
+	keyId := wire.MapT.Key
+	elemId := wire.MapT.Elem
+	u := deb.uint64()
+	length := int(u)
+	for i := 0; i < length; i++ {
+		deb.fieldValue(indent+1, keyId)
+		deb.fieldValue(indent+1, elemId)
+	}
+}
+
+// SliceValue:
+//	uint(n) (n FieldValue)
+func (deb *debugger) sliceValue(indent tab, wire *wireType) {
+	elemId := wire.SliceT.Elem
+	u := deb.uint64()
+	length := int(u)
+	deb.dump("Start of slice of length %d", length)
+
+	for i := 0; i < length; i++ {
+		deb.fieldValue(indent, elemId)
+	}
+}
+
+// StructValue:
+//	(uint(fieldDelta) FieldValue)*
+func (deb *debugger) structValue(indent tab, id typeId) {
+	deb.dump("Start of struct value of %q id=%d\n<<\n", id.name(), id)
+	fmt.Fprintf(os.Stderr, "%s%s struct {\n", indent, id.name())
+	wire, ok := deb.wireType[id]
+	if !ok {
+		errorf("type id %d not defined", id)
+	}
+	strct := wire.StructT
+	fieldNum := -1
+	indent++
+	for {
+		delta := deb.uint64()
+		if delta == 0 { // struct terminator is zero delta fieldnum
+			break
+		}
+		fieldNum += int(delta)
+		if fieldNum < 0 || fieldNum >= len(strct.Field) {
+			deb.dump("field number out of range: prevField=%d delta=%d", fieldNum-int(delta), delta)
+			break
+		}
+		fmt.Fprintf(os.Stderr, "%sfield %d:\t%s\n", indent, fieldNum, wire.StructT.Field[fieldNum].Name)
+		deb.fieldValue(indent+1, strct.Field[fieldNum].Id)
+	}
+	indent--
+	fmt.Fprintf(os.Stderr, "%s} // end %s struct\n", indent, id.name())
+	deb.dump(">> End of struct value of type %d %q", id, id.name())
+}
+
+// GobEncoderValue:
+//	uint(n) byte*n
+func (deb *debugger) gobEncoderValue(indent tab, id typeId) {
+	len := deb.uint64()
+	deb.dump("GobEncoder value of %q id=%d, length %d\n", id.name(), id, len)
+	fmt.Fprintf(os.Stderr, "%s%s (implements GobEncoder)\n", indent, id.name())
+	data := make([]byte, len)
+	_, err := deb.r.Read(data)
+	if err != nil {
+		errorf("gobEncoder data read: %s", err)
+	}
+	fmt.Fprintf(os.Stderr, "%s[% .2x]\n", indent+1, data)
+}
diff --git a/libgo/go/encoding/gob/decode.go b/libgo/go/encoding/gob/decode.go
new file mode 100644
index 00000000000..1515d1286d0
--- /dev/null
+++ b/libgo/go/encoding/gob/decode.go
@@ -0,0 +1,1279 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package gob
+
+// TODO(rsc): When garbage collector changes, revisit
+// the allocations in this file that use unsafe.Pointer.
+
+import (
+	"bytes"
+	"errors"
+	"io"
+	"math"
+	"reflect"
+	"unsafe"
+)
+
+var (
+	errBadUint = errors.New("gob: encoded unsigned integer out of range")
+	errBadType = errors.New("gob: unknown type id or corrupted data")
+	errRange   = errors.New("gob: bad data: field numbers out of bounds")
+)
+
+// decoderState is the execution state of an instance of the decoder. A new state
+// is created for nested objects.
+type decoderState struct {
+	dec *Decoder
+	// The buffer is stored with an extra indirection because it may be replaced
+	// if we load a type during decode (when reading an interface value).
+	b        *bytes.Buffer
+	fieldnum int // the last field number read.
+	buf      []byte
+	next     *decoderState // for free list
+}
+
+// We pass the bytes.Buffer separately for easier testing of the infrastructure
+// without requiring a full Decoder.
+func (dec *Decoder) newDecoderState(buf *bytes.Buffer) *decoderState {
+	d := dec.freeList
+	if d == nil {
+		d = new(decoderState)
+		d.dec = dec
+		d.buf = make([]byte, uint64Size)
+	} else {
+		dec.freeList = d.next
+	}
+	d.b = buf
+	return d
+}
+
+func (dec *Decoder) freeDecoderState(d *decoderState) {
+	d.next = dec.freeList
+	dec.freeList = d
+}
+
+func overflow(name string) error {
+	return errors.New(`value for "` + name + `" out of range`)
+}
+
+// decodeUintReader reads an encoded unsigned integer from an io.Reader.
+// Used only by the Decoder to read the message length.
+func decodeUintReader(r io.Reader, buf []byte) (x uint64, width int, err error) {
+	width = 1
+	_, err = r.Read(buf[0:width])
+	if err != nil {
+		return
+	}
+	b := buf[0]
+	if b <= 0x7f {
+		return uint64(b), width, nil
+	}
+	n := -int(int8(b))
+	if n > uint64Size {
+		err = errBadUint
+		return
+	}
+	width, err = io.ReadFull(r, buf[0:n])
+	if err != nil {
+		if err == io.EOF {
+			err = io.ErrUnexpectedEOF
+		}
+		return
+	}
+	// Could check that the high byte is zero but it's not worth it.
+	for _, b := range buf[0:width] {
+		x = x<<8 | uint64(b)
+	}
+	width++ // +1 for length byte
+	return
+}
+
+// decodeUint reads an encoded unsigned integer from state.r.
+// Does not check for overflow.
+func (state *decoderState) decodeUint() (x uint64) {
+	b, err := state.b.ReadByte()
+	if err != nil {
+		error_(err)
+	}
+	if b <= 0x7f {
+		return uint64(b)
+	}
+	n := -int(int8(b))
+	if n > uint64Size {
+		error_(errBadUint)
+	}
+	width, err := state.b.Read(state.buf[0:n])
+	if err != nil {
+		error_(err)
+	}
+	// Don't need to check error; it's safe to loop regardless.
+	// Could check that the high byte is zero but it's not worth it.
+	for _, b := range state.buf[0:width] {
+		x = x<<8 | uint64(b)
+	}
+	return x
+}
+
+// decodeInt reads an encoded signed integer from state.r.
+// Does not check for overflow.
+func (state *decoderState) decodeInt() int64 {
+	x := state.decodeUint()
+	if x&1 != 0 {
+		return ^int64(x >> 1)
+	}
+	return int64(x >> 1)
+}
+
+// decOp is the signature of a decoding operator for a given type.
+type decOp func(i *decInstr, state *decoderState, p unsafe.Pointer)
+
+// The 'instructions' of the decoding machine
+type decInstr struct {
+	op     decOp
+	field  int     // field number of the wire type
+	indir  int     // how many pointer indirections to reach the value in the struct
+	offset uintptr // offset in the structure of the field to encode
+	ovfl   error   // error message for overflow/underflow (for arrays, of the elements)
+}
+
+// Since the encoder writes no zeros, if we arrive at a decoder we have
+// a value to extract and store.  The field number has already been read
+// (it's how we knew to call this decoder).
+// Each decoder is responsible for handling any indirections associated
+// with the data structure.  If any pointer so reached is nil, allocation must
+// be done.
+
+// Walk the pointer hierarchy, allocating if we find a nil.  Stop one before the end.
+func decIndirect(p unsafe.Pointer, indir int) unsafe.Pointer {
+	for ; indir > 1; indir-- {
+		if *(*unsafe.Pointer)(p) == nil {
+			// Allocation required
+			*(*unsafe.Pointer)(p) = unsafe.Pointer(new(unsafe.Pointer))
+		}
+		p = *(*unsafe.Pointer)(p)
+	}
+	return p
+}
+
+// ignoreUint discards a uint value with no destination.
+func ignoreUint(i *decInstr, state *decoderState, p unsafe.Pointer) {
+	state.decodeUint()
+}
+
+// ignoreTwoUints discards a uint value with no destination. It's used to skip
+// complex values.
+func ignoreTwoUints(i *decInstr, state *decoderState, p unsafe.Pointer) {
+	state.decodeUint()
+	state.decodeUint()
+}
+
+// decBool decodes a uint and stores it as a boolean through p.
+func decBool(i *decInstr, state *decoderState, p unsafe.Pointer) {
+	if i.indir > 0 {
+		if *(*unsafe.Pointer)(p) == nil {
+			*(*unsafe.Pointer)(p) = unsafe.Pointer(new(bool))
+		}
+		p = *(*unsafe.Pointer)(p)
+	}
+	*(*bool)(p) = state.decodeUint() != 0
+}
+
+// decInt8 decodes an integer and stores it as an int8 through p.
+func decInt8(i *decInstr, state *decoderState, p unsafe.Pointer) {
+	if i.indir > 0 {
+		if *(*unsafe.Pointer)(p) == nil {
+			*(*unsafe.Pointer)(p) = unsafe.Pointer(new(int8))
+		}
+		p = *(*unsafe.Pointer)(p)
+	}
+	v := state.decodeInt()
+	if v < math.MinInt8 || math.MaxInt8 < v {
+		error_(i.ovfl)
+	} else {
+		*(*int8)(p) = int8(v)
+	}
+}
+
+// decUint8 decodes an unsigned integer and stores it as a uint8 through p.
+func decUint8(i *decInstr, state *decoderState, p unsafe.Pointer) {
+	if i.indir > 0 {
+		if *(*unsafe.Pointer)(p) == nil {
+			*(*unsafe.Pointer)(p) = unsafe.Pointer(new(uint8))
+		}
+		p = *(*unsafe.Pointer)(p)
+	}
+	v := state.decodeUint()
+	if math.MaxUint8 < v {
+		error_(i.ovfl)
+	} else {
+		*(*uint8)(p) = uint8(v)
+	}
+}
+
+// decInt16 decodes an integer and stores it as an int16 through p.
+func decInt16(i *decInstr, state *decoderState, p unsafe.Pointer) {
+	if i.indir > 0 {
+		if *(*unsafe.Pointer)(p) == nil {
+			*(*unsafe.Pointer)(p) = unsafe.Pointer(new(int16))
+		}
+		p = *(*unsafe.Pointer)(p)
+	}
+	v := state.decodeInt()
+	if v < math.MinInt16 || math.MaxInt16 < v {
+		error_(i.ovfl)
+	} else {
+		*(*int16)(p) = int16(v)
+	}
+}
+
+// decUint16 decodes an unsigned integer and stores it as a uint16 through p.
+func decUint16(i *decInstr, state *decoderState, p unsafe.Pointer) {
+	if i.indir > 0 {
+		if *(*unsafe.Pointer)(p) == nil {
+			*(*unsafe.Pointer)(p) = unsafe.Pointer(new(uint16))
+		}
+		p = *(*unsafe.Pointer)(p)
+	}
+	v := state.decodeUint()
+	if math.MaxUint16 < v {
+		error_(i.ovfl)
+	} else {
+		*(*uint16)(p) = uint16(v)
+	}
+}
+
+// decInt32 decodes an integer and stores it as an int32 through p.
+func decInt32(i *decInstr, state *decoderState, p unsafe.Pointer) {
+	if i.indir > 0 {
+		if *(*unsafe.Pointer)(p) == nil {
+			*(*unsafe.Pointer)(p) = unsafe.Pointer(new(int32))
+		}
+		p = *(*unsafe.Pointer)(p)
+	}
+	v := state.decodeInt()
+	if v < math.MinInt32 || math.MaxInt32 < v {
+		error_(i.ovfl)
+	} else {
+		*(*int32)(p) = int32(v)
+	}
+}
+
+// decUint32 decodes an unsigned integer and stores it as a uint32 through p.
+func decUint32(i *decInstr, state *decoderState, p unsafe.Pointer) {
+	if i.indir > 0 {
+		if *(*unsafe.Pointer)(p) == nil {
+			*(*unsafe.Pointer)(p) = unsafe.Pointer(new(uint32))
+		}
+		p = *(*unsafe.Pointer)(p)
+	}
+	v := state.decodeUint()
+	if math.MaxUint32 < v {
+		error_(i.ovfl)
+	} else {
+		*(*uint32)(p) = uint32(v)
+	}
+}
+
+// decInt64 decodes an integer and stores it as an int64 through p.
+func decInt64(i *decInstr, state *decoderState, p unsafe.Pointer) {
+	if i.indir > 0 {
+		if *(*unsafe.Pointer)(p) == nil {
+			*(*unsafe.Pointer)(p) = unsafe.Pointer(new(int64))
+		}
+		p = *(*unsafe.Pointer)(p)
+	}
+	*(*int64)(p) = int64(state.decodeInt())
+}
+
+// decUint64 decodes an unsigned integer and stores it as a uint64 through p.
+func decUint64(i *decInstr, state *decoderState, p unsafe.Pointer) {
+	if i.indir > 0 {
+		if *(*unsafe.Pointer)(p) == nil {
+			*(*unsafe.Pointer)(p) = unsafe.Pointer(new(uint64))
+		}
+		p = *(*unsafe.Pointer)(p)
+	}
+	*(*uint64)(p) = uint64(state.decodeUint())
+}
+
+// Floating-point numbers are transmitted as uint64s holding the bits
+// of the underlying representation.  They are sent byte-reversed, with
+// the exponent end coming out first, so integer floating point numbers
+// (for example) transmit more compactly.  This routine does the
+// unswizzling.
+func floatFromBits(u uint64) float64 {
+	var v uint64
+	for i := 0; i < 8; i++ {
+		v <<= 8
+		v |= u & 0xFF
+		u >>= 8
+	}
+	return math.Float64frombits(v)
+}
+
+// storeFloat32 decodes an unsigned integer, treats it as a 32-bit floating-point
+// number, and stores it through p. It's a helper function for float32 and complex64.
+func storeFloat32(i *decInstr, state *decoderState, p unsafe.Pointer) {
+	v := floatFromBits(state.decodeUint())
+	av := v
+	if av < 0 {
+		av = -av
+	}
+	// +Inf is OK in both 32- and 64-bit floats.  Underflow is always OK.
+	if math.MaxFloat32 < av && av <= math.MaxFloat64 {
+		error_(i.ovfl)
+	} else {
+		*(*float32)(p) = float32(v)
+	}
+}
+
+// decFloat32 decodes an unsigned integer, treats it as a 32-bit floating-point
+// number, and stores it through p.
+func decFloat32(i *decInstr, state *decoderState, p unsafe.Pointer) {
+	if i.indir > 0 {
+		if *(*unsafe.Pointer)(p) == nil {
+			*(*unsafe.Pointer)(p) = unsafe.Pointer(new(float32))
+		}
+		p = *(*unsafe.Pointer)(p)
+	}
+	storeFloat32(i, state, p)
+}
+
+// decFloat64 decodes an unsigned integer, treats it as a 64-bit floating-point
+// number, and stores it through p.
+func decFloat64(i *decInstr, state *decoderState, p unsafe.Pointer) {
+	if i.indir > 0 {
+		if *(*unsafe.Pointer)(p) == nil {
+			*(*unsafe.Pointer)(p) = unsafe.Pointer(new(float64))
+		}
+		p = *(*unsafe.Pointer)(p)
+	}
+	*(*float64)(p) = floatFromBits(uint64(state.decodeUint()))
+}
+
+// decComplex64 decodes a pair of unsigned integers, treats them as a
+// pair of floating point numbers, and stores them as a complex64 through p.
+// The real part comes first.
+func decComplex64(i *decInstr, state *decoderState, p unsafe.Pointer) {
+	if i.indir > 0 {
+		if *(*unsafe.Pointer)(p) == nil {
+			*(*unsafe.Pointer)(p) = unsafe.Pointer(new(complex64))
+		}
+		p = *(*unsafe.Pointer)(p)
+	}
+	storeFloat32(i, state, p)
+	storeFloat32(i, state, unsafe.Pointer(uintptr(p)+unsafe.Sizeof(float32(0))))
+}
+
+// decComplex128 decodes a pair of unsigned integers, treats them as a
+// pair of floating point numbers, and stores them as a complex128 through p.
+// The real part comes first.
+func decComplex128(i *decInstr, state *decoderState, p unsafe.Pointer) {
+	if i.indir > 0 {
+		if *(*unsafe.Pointer)(p) == nil {
+			*(*unsafe.Pointer)(p) = unsafe.Pointer(new(complex128))
+		}
+		p = *(*unsafe.Pointer)(p)
+	}
+	real := floatFromBits(uint64(state.decodeUint()))
+	imag := floatFromBits(uint64(state.decodeUint()))
+	*(*complex128)(p) = complex(real, imag)
+}
+
+// decUint8Slice decodes a byte slice and stores through p a slice header
+// describing the data.
+// uint8 slices are encoded as an unsigned count followed by the raw bytes.
+func decUint8Slice(i *decInstr, state *decoderState, p unsafe.Pointer) {
+	if i.indir > 0 {
+		if *(*unsafe.Pointer)(p) == nil {
+			*(*unsafe.Pointer)(p) = unsafe.Pointer(new([]uint8))
+		}
+		p = *(*unsafe.Pointer)(p)
+	}
+	n := int(state.decodeUint())
+	if n < 0 {
+		errorf("negative length decoding []byte")
+	}
+	slice := (*[]uint8)(p)
+	if cap(*slice) < n {
+		*slice = make([]uint8, n)
+	} else {
+		*slice = (*slice)[0:n]
+	}
+	if _, err := state.b.Read(*slice); err != nil {
+		errorf("error decoding []byte: %s", err)
+	}
+}
+
+// decString decodes byte array and stores through p a string header
+// describing the data.
+// Strings are encoded as an unsigned count followed by the raw bytes.
+func decString(i *decInstr, state *decoderState, p unsafe.Pointer) {
+	if i.indir > 0 {
+		if *(*unsafe.Pointer)(p) == nil {
+			*(*unsafe.Pointer)(p) = unsafe.Pointer(new(string))
+		}
+		p = *(*unsafe.Pointer)(p)
+	}
+	b := make([]byte, state.decodeUint())
+	state.b.Read(b)
+	// It would be a shame to do the obvious thing here,
+	//	*(*string)(p) = string(b)
+	// because we've already allocated the storage and this would
+	// allocate again and copy.  So we do this ugly hack, which is even
+	// even more unsafe than it looks as it depends the memory
+	// representation of a string matching the beginning of the memory
+	// representation of a byte slice (a byte slice is longer).
+	*(*string)(p) = *(*string)(unsafe.Pointer(&b))
+}
+
+// ignoreUint8Array skips over the data for a byte slice value with no destination.
+func ignoreUint8Array(i *decInstr, state *decoderState, p unsafe.Pointer) {
+	b := make([]byte, state.decodeUint())
+	state.b.Read(b)
+}
+
+// Execution engine
+
+// The encoder engine is an array of instructions indexed by field number of the incoming
+// decoder.  It is executed with random access according to field number.
+type decEngine struct {
+	instr    []decInstr
+	numInstr int // the number of active instructions
+}
+
+// allocate makes sure storage is available for an object of underlying type rtyp
+// that is indir levels of indirection through p.
+func allocate(rtyp reflect.Type, p uintptr, indir int) uintptr {
+	if indir == 0 {
+		return p
+	}
+	up := unsafe.Pointer(p)
+	if indir > 1 {
+		up = decIndirect(up, indir)
+	}
+	if *(*unsafe.Pointer)(up) == nil {
+		// Allocate object.
+		*(*unsafe.Pointer)(up) = unsafe.New(rtyp)
+	}
+	return *(*uintptr)(up)
+}
+
+// decodeSingle decodes a top-level value that is not a struct and stores it through p.
+// Such values are preceded by a zero, making them have the memory layout of a
+// struct field (although with an illegal field number).
+func (dec *Decoder) decodeSingle(engine *decEngine, ut *userTypeInfo, basep uintptr) (err error) {
+	state := dec.newDecoderState(&dec.buf)
+	state.fieldnum = singletonField
+	delta := int(state.decodeUint())
+	if delta != 0 {
+		errorf("decode: corrupted data: non-zero delta for singleton")
+	}
+	instr := &engine.instr[singletonField]
+	if instr.indir != ut.indir {
+		return errors.New("gob: internal error: inconsistent indirection")
+	}
+	ptr := unsafe.Pointer(basep) // offset will be zero
+	if instr.indir > 1 {
+		ptr = decIndirect(ptr, instr.indir)
+	}
+	instr.op(instr, state, ptr)
+	dec.freeDecoderState(state)
+	return nil
+}
+
+// decodeSingle decodes a top-level struct and stores it through p.
+// Indir is for the value, not the type.  At the time of the call it may
+// differ from ut.indir, which was computed when the engine was built.
+// This state cannot arise for decodeSingle, which is called directly
+// from the user's value, not from the innards of an engine.
+func (dec *Decoder) decodeStruct(engine *decEngine, ut *userTypeInfo, p uintptr, indir int) {
+	p = allocate(ut.base, p, indir)
+	state := dec.newDecoderState(&dec.buf)
+	state.fieldnum = -1
+	basep := p
+	for state.b.Len() > 0 {
+		delta := int(state.decodeUint())
+		if delta < 0 {
+			errorf("decode: corrupted data: negative delta")
+		}
+		if delta == 0 { // struct terminator is zero delta fieldnum
+			break
+		}
+		fieldnum := state.fieldnum + delta
+		if fieldnum >= len(engine.instr) {
+			error_(errRange)
+			break
+		}
+		instr := &engine.instr[fieldnum]
+		p := unsafe.Pointer(basep + instr.offset)
+		if instr.indir > 1 {
+			p = decIndirect(p, instr.indir)
+		}
+		instr.op(instr, state, p)
+		state.fieldnum = fieldnum
+	}
+	dec.freeDecoderState(state)
+}
+
+// ignoreStruct discards the data for a struct with no destination.
+func (dec *Decoder) ignoreStruct(engine *decEngine) {
+	state := dec.newDecoderState(&dec.buf)
+	state.fieldnum = -1
+	for state.b.Len() > 0 {
+		delta := int(state.decodeUint())
+		if delta < 0 {
+			errorf("ignore decode: corrupted data: negative delta")
+		}
+		if delta == 0 { // struct terminator is zero delta fieldnum
+			break
+		}
+		fieldnum := state.fieldnum + delta
+		if fieldnum >= len(engine.instr) {
+			error_(errRange)
+		}
+		instr := &engine.instr[fieldnum]
+		instr.op(instr, state, unsafe.Pointer(nil))
+		state.fieldnum = fieldnum
+	}
+	dec.freeDecoderState(state)
+}
+
+// ignoreSingle discards the data for a top-level non-struct value with no
+// destination. It's used when calling Decode with a nil value.
+func (dec *Decoder) ignoreSingle(engine *decEngine) {
+	state := dec.newDecoderState(&dec.buf)
+	state.fieldnum = singletonField
+	delta := int(state.decodeUint())
+	if delta != 0 {
+		errorf("decode: corrupted data: non-zero delta for singleton")
+	}
+	instr := &engine.instr[singletonField]
+	instr.op(instr, state, unsafe.Pointer(nil))
+	dec.freeDecoderState(state)
+}
+
+// decodeArrayHelper does the work for decoding arrays and slices.
+func (dec *Decoder) decodeArrayHelper(state *decoderState, p uintptr, elemOp decOp, elemWid uintptr, length, elemIndir int, ovfl error) {
+	instr := &decInstr{elemOp, 0, elemIndir, 0, ovfl}
+	for i := 0; i < length; i++ {
+		up := unsafe.Pointer(p)
+		if elemIndir > 1 {
+			up = decIndirect(up, elemIndir)
+		}
+		elemOp(instr, state, up)
+		p += uintptr(elemWid)
+	}
+}
+
+// decodeArray decodes an array and stores it through p, that is, p points to the zeroth element.
+// The length is an unsigned integer preceding the elements.  Even though the length is redundant
+// (it's part of the type), it's a useful check and is included in the encoding.
+func (dec *Decoder) decodeArray(atyp reflect.Type, state *decoderState, p uintptr, elemOp decOp, elemWid uintptr, length, indir, elemIndir int, ovfl error) {
+	if indir > 0 {
+		p = allocate(atyp, p, 1) // All but the last level has been allocated by dec.Indirect
+	}
+	if n := state.decodeUint(); n != uint64(length) {
+		errorf("length mismatch in decodeArray")
+	}
+	dec.decodeArrayHelper(state, p, elemOp, elemWid, length, elemIndir, ovfl)
+}
+
+// decodeIntoValue is a helper for map decoding.  Since maps are decoded using reflection,
+// unlike the other items we can't use a pointer directly.
+func decodeIntoValue(state *decoderState, op decOp, indir int, v reflect.Value, ovfl error) reflect.Value {
+	instr := &decInstr{op, 0, indir, 0, ovfl}
+	up := unsafe.Pointer(unsafeAddr(v))
+	if indir > 1 {
+		up = decIndirect(up, indir)
+	}
+	op(instr, state, up)
+	return v
+}
+
+// decodeMap decodes a map and stores its header through p.
+// Maps are encoded as a length followed by key:value pairs.
+// Because the internals of maps are not visible to us, we must
+// use reflection rather than pointer magic.
+func (dec *Decoder) decodeMap(mtyp reflect.Type, state *decoderState, p uintptr, keyOp, elemOp decOp, indir, keyIndir, elemIndir int, ovfl error) {
+	if indir > 0 {
+		p = allocate(mtyp, p, 1) // All but the last level has been allocated by dec.Indirect
+	}
+	up := unsafe.Pointer(p)
+	if *(*unsafe.Pointer)(up) == nil { // maps are represented as a pointer in the runtime
+		// Allocate map.
+		*(*unsafe.Pointer)(up) = unsafe.Pointer(reflect.MakeMap(mtyp).Pointer())
+	}
+	// Maps cannot be accessed by moving addresses around the way
+	// that slices etc. can.  We must recover a full reflection value for
+	// the iteration.
+	v := reflect.ValueOf(unsafe.Unreflect(mtyp, unsafe.Pointer(p)))
+	n := int(state.decodeUint())
+	for i := 0; i < n; i++ {
+		key := decodeIntoValue(state, keyOp, keyIndir, allocValue(mtyp.Key()), ovfl)
+		elem := decodeIntoValue(state, elemOp, elemIndir, allocValue(mtyp.Elem()), ovfl)
+		v.SetMapIndex(key, elem)
+	}
+}
+
+// ignoreArrayHelper does the work for discarding arrays and slices.
+func (dec *Decoder) ignoreArrayHelper(state *decoderState, elemOp decOp, length int) {
+	instr := &decInstr{elemOp, 0, 0, 0, errors.New("no error")}
+	for i := 0; i < length; i++ {
+		elemOp(instr, state, nil)
+	}
+}
+
+// ignoreArray discards the data for an array value with no destination.
+func (dec *Decoder) ignoreArray(state *decoderState, elemOp decOp, length int) {
+	if n := state.decodeUint(); n != uint64(length) {
+		errorf("length mismatch in ignoreArray")
+	}
+	dec.ignoreArrayHelper(state, elemOp, length)
+}
+
+// ignoreMap discards the data for a map value with no destination.
+func (dec *Decoder) ignoreMap(state *decoderState, keyOp, elemOp decOp) {
+	n := int(state.decodeUint())
+	keyInstr := &decInstr{keyOp, 0, 0, 0, errors.New("no error")}
+	elemInstr := &decInstr{elemOp, 0, 0, 0, errors.New("no error")}
+	for i := 0; i < n; i++ {
+		keyOp(keyInstr, state, nil)
+		elemOp(elemInstr, state, nil)
+	}
+}
+
+// decodeSlice decodes a slice and stores the slice header through p.
+// Slices are encoded as an unsigned length followed by the elements.
+func (dec *Decoder) decodeSlice(atyp reflect.Type, state *decoderState, p uintptr, elemOp decOp, elemWid uintptr, indir, elemIndir int, ovfl error) {
+	n := int(uintptr(state.decodeUint()))
+	if indir > 0 {
+		up := unsafe.Pointer(p)
+		if *(*unsafe.Pointer)(up) == nil {
+			// Allocate the slice header.
+			*(*unsafe.Pointer)(up) = unsafe.Pointer(new([]unsafe.Pointer))
+		}
+		p = *(*uintptr)(up)
+	}
+	// Allocate storage for the slice elements, that is, the underlying array,
+	// if the existing slice does not have the capacity.
+	// Always write a header at p.
+	hdrp := (*reflect.SliceHeader)(unsafe.Pointer(p))
+	if hdrp.Cap < n {
+		hdrp.Data = uintptr(unsafe.NewArray(atyp.Elem(), n))
+		hdrp.Cap = n
+	}
+	hdrp.Len = n
+	dec.decodeArrayHelper(state, hdrp.Data, elemOp, elemWid, n, elemIndir, ovfl)
+}
+
+// ignoreSlice skips over the data for a slice value with no destination.
+func (dec *Decoder) ignoreSlice(state *decoderState, elemOp decOp) {
+	dec.ignoreArrayHelper(state, elemOp, int(state.decodeUint()))
+}
+
+// setInterfaceValue sets an interface value to a concrete value,
+// but first it checks that the assignment will succeed.
+func setInterfaceValue(ivalue reflect.Value, value reflect.Value) {
+	if !value.Type().AssignableTo(ivalue.Type()) {
+		errorf("cannot assign value of type %s to %s", value.Type(), ivalue.Type())
+	}
+	ivalue.Set(value)
+}
+
+// decodeInterface decodes an interface value and stores it through p.
+// Interfaces are encoded as the name of a concrete type followed by a value.
+// If the name is empty, the value is nil and no value is sent.
+func (dec *Decoder) decodeInterface(ityp reflect.Type, state *decoderState, p uintptr, indir int) {
+	// Create a writable interface reflect.Value.  We need one even for the nil case.
+	ivalue := allocValue(ityp)
+	// Read the name of the concrete type.
+	b := make([]byte, state.decodeUint())
+	state.b.Read(b)
+	name := string(b)
+	if name == "" {
+		// Copy the representation of the nil interface value to the target.
+		// This is horribly unsafe and special.
+		*(*[2]uintptr)(unsafe.Pointer(p)) = ivalue.InterfaceData()
+		return
+	}
+	// The concrete type must be registered.
+	typ, ok := nameToConcreteType[name]
+	if !ok {
+		errorf("name not registered for interface: %q", name)
+	}
+	// Read the type id of the concrete value.
+	concreteId := dec.decodeTypeSequence(true)
+	if concreteId < 0 {
+		error_(dec.err)
+	}
+	// Byte count of value is next; we don't care what it is (it's there
+	// in case we want to ignore the value by skipping it completely).
+	state.decodeUint()
+	// Read the concrete value.
+	value := allocValue(typ)
+	dec.decodeValue(concreteId, value)
+	if dec.err != nil {
+		error_(dec.err)
+	}
+	// Allocate the destination interface value.
+	if indir > 0 {
+		p = allocate(ityp, p, 1) // All but the last level has been allocated by dec.Indirect
+	}
+	// Assign the concrete value to the interface.
+	// Tread carefully; it might not satisfy the interface.
+	setInterfaceValue(ivalue, value)
+	// Copy the representation of the interface value to the target.
+	// This is horribly unsafe and special.
+	*(*[2]uintptr)(unsafe.Pointer(p)) = ivalue.InterfaceData()
+}
+
+// ignoreInterface discards the data for an interface value with no destination.
+func (dec *Decoder) ignoreInterface(state *decoderState) {
+	// Read the name of the concrete type.
+	b := make([]byte, state.decodeUint())
+	_, err := state.b.Read(b)
+	if err != nil {
+		error_(err)
+	}
+	id := dec.decodeTypeSequence(true)
+	if id < 0 {
+		error_(dec.err)
+	}
+	// At this point, the decoder buffer contains a delimited value. Just toss it.
+	state.b.Next(int(state.decodeUint()))
+}
+
+// decodeGobDecoder decodes something implementing the GobDecoder interface.
+// The data is encoded as a byte slice.
+func (dec *Decoder) decodeGobDecoder(state *decoderState, v reflect.Value) {
+	// Read the bytes for the value.
+	b := make([]byte, state.decodeUint())
+	_, err := state.b.Read(b)
+	if err != nil {
+		error_(err)
+	}
+	// We know it's a GobDecoder, so just call the method directly.
+	err = v.Interface().(GobDecoder).GobDecode(b)
+	if err != nil {
+		error_(err)
+	}
+}
+
+// ignoreGobDecoder discards the data for a GobDecoder value with no destination.
+func (dec *Decoder) ignoreGobDecoder(state *decoderState) {
+	// Read the bytes for the value.
+	b := make([]byte, state.decodeUint())
+	_, err := state.b.Read(b)
+	if err != nil {
+		error_(err)
+	}
+}
+
+// Index by Go types.
+var decOpTable = [...]decOp{
+	reflect.Bool:       decBool,
+	reflect.Int8:       decInt8,
+	reflect.Int16:      decInt16,
+	reflect.Int32:      decInt32,
+	reflect.Int64:      decInt64,
+	reflect.Uint8:      decUint8,
+	reflect.Uint16:     decUint16,
+	reflect.Uint32:     decUint32,
+	reflect.Uint64:     decUint64,
+	reflect.Float32:    decFloat32,
+	reflect.Float64:    decFloat64,
+	reflect.Complex64:  decComplex64,
+	reflect.Complex128: decComplex128,
+	reflect.String:     decString,
+}
+
+// Indexed by gob types.  tComplex will be added during type.init().
+var decIgnoreOpMap = map[typeId]decOp{
+	tBool:    ignoreUint,
+	tInt:     ignoreUint,
+	tUint:    ignoreUint,
+	tFloat:   ignoreUint,
+	tBytes:   ignoreUint8Array,
+	tString:  ignoreUint8Array,
+	tComplex: ignoreTwoUints,
+}
+
+// decOpFor returns the decoding op for the base type under rt and
+// the indirection count to reach it.
+func (dec *Decoder) decOpFor(wireId typeId, rt reflect.Type, name string, inProgress map[reflect.Type]*decOp) (*decOp, int) {
+	ut := userType(rt)
+	// If the type implements GobEncoder, we handle it without further processing.
+	if ut.isGobDecoder {
+		return dec.gobDecodeOpFor(ut)
+	}
+	// If this type is already in progress, it's a recursive type (e.g. map[string]*T).
+	// Return the pointer to the op we're already building.
+	if opPtr := inProgress[rt]; opPtr != nil {
+		return opPtr, ut.indir
+	}
+	typ := ut.base
+	indir := ut.indir
+	var op decOp
+	k := typ.Kind()
+	if int(k) < len(decOpTable) {
+		op = decOpTable[k]
+	}
+	if op == nil {
+		inProgress[rt] = &op
+		// Special cases
+		switch t := typ; t.Kind() {
+		case reflect.Array:
+			name = "element of " + name
+			elemId := dec.wireType[wireId].ArrayT.Elem
+			elemOp, elemIndir := dec.decOpFor(elemId, t.Elem(), name, inProgress)
+			ovfl := overflow(name)
+			op = func(i *decInstr, state *decoderState, p unsafe.Pointer) {
+				state.dec.decodeArray(t, state, uintptr(p), *elemOp, t.Elem().Size(), t.Len(), i.indir, elemIndir, ovfl)
+			}
+
+		case reflect.Map:
+			name = "element of " + name
+			keyId := dec.wireType[wireId].MapT.Key
+			elemId := dec.wireType[wireId].MapT.Elem
+			keyOp, keyIndir := dec.decOpFor(keyId, t.Key(), name, inProgress)
+			elemOp, elemIndir := dec.decOpFor(elemId, t.Elem(), name, inProgress)
+			ovfl := overflow(name)
+			op = func(i *decInstr, state *decoderState, p unsafe.Pointer) {
+				up := unsafe.Pointer(p)
+				state.dec.decodeMap(t, state, uintptr(up), *keyOp, *elemOp, i.indir, keyIndir, elemIndir, ovfl)
+			}
+
+		case reflect.Slice:
+			name = "element of " + name
+			if t.Elem().Kind() == reflect.Uint8 {
+				op = decUint8Slice
+				break
+			}
+			var elemId typeId
+			if tt, ok := builtinIdToType[wireId]; ok {
+				elemId = tt.(*sliceType).Elem
+			} else {
+				elemId = dec.wireType[wireId].SliceT.Elem
+			}
+			elemOp, elemIndir := dec.decOpFor(elemId, t.Elem(), name, inProgress)
+			ovfl := overflow(name)
+			op = func(i *decInstr, state *decoderState, p unsafe.Pointer) {
+				state.dec.decodeSlice(t, state, uintptr(p), *elemOp, t.Elem().Size(), i.indir, elemIndir, ovfl)
+			}
+
+		case reflect.Struct:
+			// Generate a closure that calls out to the engine for the nested type.
+			enginePtr, err := dec.getDecEnginePtr(wireId, userType(typ))
+			if err != nil {
+				error_(err)
+			}
+			op = func(i *decInstr, state *decoderState, p unsafe.Pointer) {
+				// indirect through enginePtr to delay evaluation for recursive structs.
+				dec.decodeStruct(*enginePtr, userType(typ), uintptr(p), i.indir)
+			}
+		case reflect.Interface:
+			op = func(i *decInstr, state *decoderState, p unsafe.Pointer) {
+				state.dec.decodeInterface(t, state, uintptr(p), i.indir)
+			}
+		}
+	}
+	if op == nil {
+		errorf("decode can't handle type %s", rt)
+	}
+	return &op, indir
+}
+
+// decIgnoreOpFor returns the decoding op for a field that has no destination.
+func (dec *Decoder) decIgnoreOpFor(wireId typeId) decOp {
+	op, ok := decIgnoreOpMap[wireId]
+	if !ok {
+		if wireId == tInterface {
+			// Special case because it's a method: the ignored item might
+			// define types and we need to record their state in the decoder.
+			op = func(i *decInstr, state *decoderState, p unsafe.Pointer) {
+				state.dec.ignoreInterface(state)
+			}
+			return op
+		}
+		// Special cases
+		wire := dec.wireType[wireId]
+		switch {
+		case wire == nil:
+			errorf("bad data: undefined type %s", wireId.string())
+		case wire.ArrayT != nil:
+			elemId := wire.ArrayT.Elem
+			elemOp := dec.decIgnoreOpFor(elemId)
+			op = func(i *decInstr, state *decoderState, p unsafe.Pointer) {
+				state.dec.ignoreArray(state, elemOp, wire.ArrayT.Len)
+			}
+
+		case wire.MapT != nil:
+			keyId := dec.wireType[wireId].MapT.Key
+			elemId := dec.wireType[wireId].MapT.Elem
+			keyOp := dec.decIgnoreOpFor(keyId)
+			elemOp := dec.decIgnoreOpFor(elemId)
+			op = func(i *decInstr, state *decoderState, p unsafe.Pointer) {
+				state.dec.ignoreMap(state, keyOp, elemOp)
+			}
+
+		case wire.SliceT != nil:
+			elemId := wire.SliceT.Elem
+			elemOp := dec.decIgnoreOpFor(elemId)
+			op = func(i *decInstr, state *decoderState, p unsafe.Pointer) {
+				state.dec.ignoreSlice(state, elemOp)
+			}
+
+		case wire.StructT != nil:
+			// Generate a closure that calls out to the engine for the nested type.
+			enginePtr, err := dec.getIgnoreEnginePtr(wireId)
+			if err != nil {
+				error_(err)
+			}
+			op = func(i *decInstr, state *decoderState, p unsafe.Pointer) {
+				// indirect through enginePtr to delay evaluation for recursive structs
+				state.dec.ignoreStruct(*enginePtr)
+			}
+
+		case wire.GobEncoderT != nil:
+			op = func(i *decInstr, state *decoderState, p unsafe.Pointer) {
+				state.dec.ignoreGobDecoder(state)
+			}
+		}
+	}
+	if op == nil {
+		errorf("bad data: ignore can't handle type %s", wireId.string())
+	}
+	return op
+}
+
+// gobDecodeOpFor returns the op for a type that is known to implement
+// GobDecoder.
+func (dec *Decoder) gobDecodeOpFor(ut *userTypeInfo) (*decOp, int) {
+	rcvrType := ut.user
+	if ut.decIndir == -1 {
+		rcvrType = reflect.PtrTo(rcvrType)
+	} else if ut.decIndir > 0 {
+		for i := int8(0); i < ut.decIndir; i++ {
+			rcvrType = rcvrType.Elem()
+		}
+	}
+	var op decOp
+	op = func(i *decInstr, state *decoderState, p unsafe.Pointer) {
+		// Caller has gotten us to within one indirection of our value.
+		if i.indir > 0 {
+			if *(*unsafe.Pointer)(p) == nil {
+				*(*unsafe.Pointer)(p) = unsafe.New(ut.base)
+			}
+		}
+		// Now p is a pointer to the base type.  Do we need to climb out to
+		// get to the receiver type?
+		var v reflect.Value
+		if ut.decIndir == -1 {
+			v = reflect.ValueOf(unsafe.Unreflect(rcvrType, unsafe.Pointer(&p)))
+		} else {
+			v = reflect.ValueOf(unsafe.Unreflect(rcvrType, p))
+		}
+		state.dec.decodeGobDecoder(state, v)
+	}
+	return &op, int(ut.indir)
+
+}
+
+// compatibleType asks: Are these two gob Types compatible?
+// Answers the question for basic types, arrays, maps and slices, plus
+// GobEncoder/Decoder pairs.
+// Structs are considered ok; fields will be checked later.
+func (dec *Decoder) compatibleType(fr reflect.Type, fw typeId, inProgress map[reflect.Type]typeId) bool {
+	if rhs, ok := inProgress[fr]; ok {
+		return rhs == fw
+	}
+	inProgress[fr] = fw
+	ut := userType(fr)
+	wire, ok := dec.wireType[fw]
+	// If fr is a GobDecoder, the wire type must be GobEncoder.
+	// And if fr is not a GobDecoder, the wire type must not be either.
+	if ut.isGobDecoder != (ok && wire.GobEncoderT != nil) { // the parentheses look odd but are correct.
+		return false
+	}
+	if ut.isGobDecoder { // This test trumps all others.
+		return true
+	}
+	switch t := ut.base; t.Kind() {
+	default:
+		// chan, etc: cannot handle.
+		return false
+	case reflect.Bool:
+		return fw == tBool
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		return fw == tInt
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+		return fw == tUint
+	case reflect.Float32, reflect.Float64:
+		return fw == tFloat
+	case reflect.Complex64, reflect.Complex128:
+		return fw == tComplex
+	case reflect.String:
+		return fw == tString
+	case reflect.Interface:
+		return fw == tInterface
+	case reflect.Array:
+		if !ok || wire.ArrayT == nil {
+			return false
+		}
+		array := wire.ArrayT
+		return t.Len() == array.Len && dec.compatibleType(t.Elem(), array.Elem, inProgress)
+	case reflect.Map:
+		if !ok || wire.MapT == nil {
+			return false
+		}
+		MapType := wire.MapT
+		return dec.compatibleType(t.Key(), MapType.Key, inProgress) && dec.compatibleType(t.Elem(), MapType.Elem, inProgress)
+	case reflect.Slice:
+		// Is it an array of bytes?
+		if t.Elem().Kind() == reflect.Uint8 {
+			return fw == tBytes
+		}
+		// Extract and compare element types.
+		var sw *sliceType
+		if tt, ok := builtinIdToType[fw]; ok {
+			sw = tt.(*sliceType)
+		} else {
+			sw = dec.wireType[fw].SliceT
+		}
+		elem := userType(t.Elem()).base
+		return sw != nil && dec.compatibleType(elem, sw.Elem, inProgress)
+	case reflect.Struct:
+		return true
+	}
+	return true
+}
+
+// typeString returns a human-readable description of the type identified by remoteId.
+func (dec *Decoder) typeString(remoteId typeId) string {
+	if t := idToType[remoteId]; t != nil {
+		// globally known type.
+		return t.string()
+	}
+	return dec.wireType[remoteId].string()
+}
+
+// compileSingle compiles the decoder engine for a non-struct top-level value, including
+// GobDecoders.
+func (dec *Decoder) compileSingle(remoteId typeId, ut *userTypeInfo) (engine *decEngine, err error) {
+	rt := ut.user
+	engine = new(decEngine)
+	engine.instr = make([]decInstr, 1) // one item
+	name := rt.String()                // best we can do
+	if !dec.compatibleType(rt, remoteId, make(map[reflect.Type]typeId)) {
+		return nil, errors.New("gob: wrong type received for local value " + name + ": " + dec.typeString(remoteId))
+	}
+	op, indir := dec.decOpFor(remoteId, rt, name, make(map[reflect.Type]*decOp))
+	ovfl := errors.New(`value for "` + name + `" out of range`)
+	engine.instr[singletonField] = decInstr{*op, singletonField, indir, 0, ovfl}
+	engine.numInstr = 1
+	return
+}
+
+// compileIgnoreSingle compiles the decoder engine for a non-struct top-level value that will be discarded.
+func (dec *Decoder) compileIgnoreSingle(remoteId typeId) (engine *decEngine, err error) {
+	engine = new(decEngine)
+	engine.instr = make([]decInstr, 1) // one item
+	op := dec.decIgnoreOpFor(remoteId)
+	ovfl := overflow(dec.typeString(remoteId))
+	engine.instr[0] = decInstr{op, 0, 0, 0, ovfl}
+	engine.numInstr = 1
+	return
+}
+
+// compileDec compiles the decoder engine for a value.  If the value is not a struct,
+// it calls out to compileSingle.
+func (dec *Decoder) compileDec(remoteId typeId, ut *userTypeInfo) (engine *decEngine, err error) {
+	rt := ut.base
+	srt := rt
+	if srt.Kind() != reflect.Struct ||
+		ut.isGobDecoder {
+		return dec.compileSingle(remoteId, ut)
+	}
+	var wireStruct *structType
+	// Builtin types can come from global pool; the rest must be defined by the decoder.
+	// Also we know we're decoding a struct now, so the client must have sent one.
+	if t, ok := builtinIdToType[remoteId]; ok {
+		wireStruct, _ = t.(*structType)
+	} else {
+		wire := dec.wireType[remoteId]
+		if wire == nil {
+			error_(errBadType)
+		}
+		wireStruct = wire.StructT
+	}
+	if wireStruct == nil {
+		errorf("type mismatch in decoder: want struct type %s; got non-struct", rt)
+	}
+	engine = new(decEngine)
+	engine.instr = make([]decInstr, len(wireStruct.Field))
+	seen := make(map[reflect.Type]*decOp)
+	// Loop over the fields of the wire type.
+	for fieldnum := 0; fieldnum < len(wireStruct.Field); fieldnum++ {
+		wireField := wireStruct.Field[fieldnum]
+		if wireField.Name == "" {
+			errorf("empty name for remote field of type %s", wireStruct.Name)
+		}
+		ovfl := overflow(wireField.Name)
+		// Find the field of the local type with the same name.
+		localField, present := srt.FieldByName(wireField.Name)
+		// TODO(r): anonymous names
+		if !present || !isExported(wireField.Name) {
+			op := dec.decIgnoreOpFor(wireField.Id)
+			engine.instr[fieldnum] = decInstr{op, fieldnum, 0, 0, ovfl}
+			continue
+		}
+		if !dec.compatibleType(localField.Type, wireField.Id, make(map[reflect.Type]typeId)) {
+			errorf("wrong type (%s) for received field %s.%s", localField.Type, wireStruct.Name, wireField.Name)
+		}
+		op, indir := dec.decOpFor(wireField.Id, localField.Type, localField.Name, seen)
+		engine.instr[fieldnum] = decInstr{*op, fieldnum, indir, uintptr(localField.Offset), ovfl}
+		engine.numInstr++
+	}
+	return
+}
+
+// getDecEnginePtr returns the engine for the specified type.
+func (dec *Decoder) getDecEnginePtr(remoteId typeId, ut *userTypeInfo) (enginePtr **decEngine, err error) {
+	rt := ut.base
+	decoderMap, ok := dec.decoderCache[rt]
+	if !ok {
+		decoderMap = make(map[typeId]**decEngine)
+		dec.decoderCache[rt] = decoderMap
+	}
+	if enginePtr, ok = decoderMap[remoteId]; !ok {
+		// To handle recursive types, mark this engine as underway before compiling.
+		enginePtr = new(*decEngine)
+		decoderMap[remoteId] = enginePtr
+		*enginePtr, err = dec.compileDec(remoteId, ut)
+		if err != nil {
+			delete(decoderMap, remoteId)
+		}
+	}
+	return
+}
+
+// emptyStruct is the type we compile into when ignoring a struct value.
+type emptyStruct struct{}
+
+var emptyStructType = reflect.TypeOf(emptyStruct{})
+
+// getDecEnginePtr returns the engine for the specified type when the value is to be discarded.
+func (dec *Decoder) getIgnoreEnginePtr(wireId typeId) (enginePtr **decEngine, err error) {
+	var ok bool
+	if enginePtr, ok = dec.ignorerCache[wireId]; !ok {
+		// To handle recursive types, mark this engine as underway before compiling.
+		enginePtr = new(*decEngine)
+		dec.ignorerCache[wireId] = enginePtr
+		wire := dec.wireType[wireId]
+		if wire != nil && wire.StructT != nil {
+			*enginePtr, err = dec.compileDec(wireId, userType(emptyStructType))
+		} else {
+			*enginePtr, err = dec.compileIgnoreSingle(wireId)
+		}
+		if err != nil {
+			delete(dec.ignorerCache, wireId)
+		}
+	}
+	return
+}
+
+// decodeValue decodes the data stream representing a value and stores it in val.
+func (dec *Decoder) decodeValue(wireId typeId, val reflect.Value) {
+	defer catchError(&dec.err)
+	// If the value is nil, it means we should just ignore this item.
+	if !val.IsValid() {
+		dec.decodeIgnoredValue(wireId)
+		return
+	}
+	// Dereference down to the underlying type.
+	ut := userType(val.Type())
+	base := ut.base
+	var enginePtr **decEngine
+	enginePtr, dec.err = dec.getDecEnginePtr(wireId, ut)
+	if dec.err != nil {
+		return
+	}
+	engine := *enginePtr
+	if st := base; st.Kind() == reflect.Struct && !ut.isGobDecoder {
+		if engine.numInstr == 0 && st.NumField() > 0 && len(dec.wireType[wireId].StructT.Field) > 0 {
+			name := base.Name()
+			errorf("type mismatch: no fields matched compiling decoder for %s", name)
+		}
+		dec.decodeStruct(engine, ut, uintptr(unsafeAddr(val)), ut.indir)
+	} else {
+		dec.decodeSingle(engine, ut, uintptr(unsafeAddr(val)))
+	}
+}
+
+// decodeIgnoredValue decodes the data stream representing a value of the specified type and discards it.
+func (dec *Decoder) decodeIgnoredValue(wireId typeId) {
+	var enginePtr **decEngine
+	enginePtr, dec.err = dec.getIgnoreEnginePtr(wireId)
+	if dec.err != nil {
+		return
+	}
+	wire := dec.wireType[wireId]
+	if wire != nil && wire.StructT != nil {
+		dec.ignoreStruct(*enginePtr)
+	} else {
+		dec.ignoreSingle(*enginePtr)
+	}
+}
+
+func init() {
+	var iop, uop decOp
+	switch reflect.TypeOf(int(0)).Bits() {
+	case 32:
+		iop = decInt32
+		uop = decUint32
+	case 64:
+		iop = decInt64
+		uop = decUint64
+	default:
+		panic("gob: unknown size of int/uint")
+	}
+	decOpTable[reflect.Int] = iop
+	decOpTable[reflect.Uint] = uop
+
+	// Finally uintptr
+	switch reflect.TypeOf(uintptr(0)).Bits() {
+	case 32:
+		uop = decUint32
+	case 64:
+		uop = decUint64
+	default:
+		panic("gob: unknown size of uintptr")
+	}
+	decOpTable[reflect.Uintptr] = uop
+}
+
+// Gob assumes it can call UnsafeAddr on any Value
+// in order to get a pointer it can copy data from.
+// Values that have just been created and do not point
+// into existing structs or slices cannot be addressed,
+// so simulate it by returning a pointer to a copy.
+// Each call allocates once.
+func unsafeAddr(v reflect.Value) uintptr {
+	if v.CanAddr() {
+		return v.UnsafeAddr()
+	}
+	x := reflect.New(v.Type()).Elem()
+	x.Set(v)
+	return x.UnsafeAddr()
+}
+
+// Gob depends on being able to take the address
+// of zeroed Values it creates, so use this wrapper instead
+// of the standard reflect.Zero.
+// Each call allocates once.
+func allocValue(t reflect.Type) reflect.Value {
+	return reflect.New(t).Elem()
+}
diff --git a/libgo/go/encoding/gob/decoder.go b/libgo/go/encoding/gob/decoder.go
new file mode 100644
index 00000000000..5e684d3ee7e
--- /dev/null
+++ b/libgo/go/encoding/gob/decoder.go
@@ -0,0 +1,214 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package gob
+
+import (
+	"bufio"
+	"bytes"
+	"errors"
+	"io"
+	"reflect"
+	"sync"
+)
+
+// A Decoder manages the receipt of type and data information read from the
+// remote side of a connection.
+type Decoder struct {
+	mutex        sync.Mutex                              // each item must be received atomically
+	r            io.Reader                               // source of the data
+	buf          bytes.Buffer                            // buffer for more efficient i/o from r
+	wireType     map[typeId]*wireType                    // map from remote ID to local description
+	decoderCache map[reflect.Type]map[typeId]**decEngine // cache of compiled engines
+	ignorerCache map[typeId]**decEngine                  // ditto for ignored objects
+	freeList     *decoderState                           // list of free decoderStates; avoids reallocation
+	countBuf     []byte                                  // used for decoding integers while parsing messages
+	tmp          []byte                                  // temporary storage for i/o; saves reallocating
+	err          error
+}
+
+// NewDecoder returns a new decoder that reads from the io.Reader.
+// If r does not also implement io.ByteReader, it will be wrapped in a
+// bufio.Reader.
+func NewDecoder(r io.Reader) *Decoder {
+	dec := new(Decoder)
+	// We use the ability to read bytes as a plausible surrogate for buffering.
+	if _, ok := r.(io.ByteReader); !ok {
+		r = bufio.NewReader(r)
+	}
+	dec.r = r
+	dec.wireType = make(map[typeId]*wireType)
+	dec.decoderCache = make(map[reflect.Type]map[typeId]**decEngine)
+	dec.ignorerCache = make(map[typeId]**decEngine)
+	dec.countBuf = make([]byte, 9) // counts may be uint64s (unlikely!), require 9 bytes
+
+	return dec
+}
+
+// recvType loads the definition of a type.
+func (dec *Decoder) recvType(id typeId) {
+	// Have we already seen this type?  That's an error
+	if id < firstUserId || dec.wireType[id] != nil {
+		dec.err = errors.New("gob: duplicate type received")
+		return
+	}
+
+	// Type:
+	wire := new(wireType)
+	dec.decodeValue(tWireType, reflect.ValueOf(wire))
+	if dec.err != nil {
+		return
+	}
+	// Remember we've seen this type.
+	dec.wireType[id] = wire
+}
+
+var errBadCount = errors.New("invalid message length")
+
+// recvMessage reads the next count-delimited item from the input. It is the converse
+// of Encoder.writeMessage. It returns false on EOF or other error reading the message.
+func (dec *Decoder) recvMessage() bool {
+	// Read a count.
+	nbytes, _, err := decodeUintReader(dec.r, dec.countBuf)
+	if err != nil {
+		dec.err = err
+		return false
+	}
+	if nbytes >= 1<<31 {
+		dec.err = errBadCount
+		return false
+	}
+	dec.readMessage(int(nbytes))
+	return dec.err == nil
+}
+
+// readMessage reads the next nbytes bytes from the input.
+func (dec *Decoder) readMessage(nbytes int) {
+	// Allocate the buffer.
+	if cap(dec.tmp) < nbytes {
+		dec.tmp = make([]byte, nbytes+100) // room to grow
+	}
+	dec.tmp = dec.tmp[:nbytes]
+
+	// Read the data
+	_, dec.err = io.ReadFull(dec.r, dec.tmp)
+	if dec.err != nil {
+		if dec.err == io.EOF {
+			dec.err = io.ErrUnexpectedEOF
+		}
+		return
+	}
+	dec.buf.Write(dec.tmp)
+}
+
+// toInt turns an encoded uint64 into an int, according to the marshaling rules.
+func toInt(x uint64) int64 {
+	i := int64(x >> 1)
+	if x&1 != 0 {
+		i = ^i
+	}
+	return i
+}
+
+func (dec *Decoder) nextInt() int64 {
+	n, _, err := decodeUintReader(&dec.buf, dec.countBuf)
+	if err != nil {
+		dec.err = err
+	}
+	return toInt(n)
+}
+
+func (dec *Decoder) nextUint() uint64 {
+	n, _, err := decodeUintReader(&dec.buf, dec.countBuf)
+	if err != nil {
+		dec.err = err
+	}
+	return n
+}
+
+// decodeTypeSequence parses:
+// TypeSequence
+//	(TypeDefinition DelimitedTypeDefinition*)?
+// and returns the type id of the next value.  It returns -1 at
+// EOF.  Upon return, the remainder of dec.buf is the value to be
+// decoded.  If this is an interface value, it can be ignored by
+// simply resetting that buffer.
+func (dec *Decoder) decodeTypeSequence(isInterface bool) typeId {
+	for dec.err == nil {
+		if dec.buf.Len() == 0 {
+			if !dec.recvMessage() {
+				break
+			}
+		}
+		// Receive a type id.
+		id := typeId(dec.nextInt())
+		if id >= 0 {
+			// Value follows.
+			return id
+		}
+		// Type definition for (-id) follows.
+		dec.recvType(-id)
+		// When decoding an interface, after a type there may be a
+		// DelimitedValue still in the buffer.  Skip its count.
+		// (Alternatively, the buffer is empty and the byte count
+		// will be absorbed by recvMessage.)
+		if dec.buf.Len() > 0 {
+			if !isInterface {
+				dec.err = errors.New("extra data in buffer")
+				break
+			}
+			dec.nextUint()
+		}
+	}
+	return -1
+}
+
+// Decode reads the next value from the connection and stores
+// it in the data represented by the empty interface value.
+// If e is nil, the value will be discarded. Otherwise,
+// the value underlying e must be a pointer to the
+// correct type for the next data item received.
+func (dec *Decoder) Decode(e interface{}) error {
+	if e == nil {
+		return dec.DecodeValue(reflect.Value{})
+	}
+	value := reflect.ValueOf(e)
+	// If e represents a value as opposed to a pointer, the answer won't
+	// get back to the caller.  Make sure it's a pointer.
+	if value.Type().Kind() != reflect.Ptr {
+		dec.err = errors.New("gob: attempt to decode into a non-pointer")
+		return dec.err
+	}
+	return dec.DecodeValue(value)
+}
+
+// DecodeValue reads the next value from the connection.
+// If v is the zero reflect.Value (v.Kind() == Invalid), DecodeValue discards the value.
+// Otherwise, it stores the value into v.  In that case, v must represent
+// a non-nil pointer to data or be an assignable reflect.Value (v.CanSet())
+func (dec *Decoder) DecodeValue(v reflect.Value) error {
+	if v.IsValid() {
+		if v.Kind() == reflect.Ptr && !v.IsNil() {
+			// That's okay, we'll store through the pointer.
+		} else if !v.CanSet() {
+			return errors.New("gob: DecodeValue of unassignable value")
+		}
+	}
+	// Make sure we're single-threaded through here.
+	dec.mutex.Lock()
+	defer dec.mutex.Unlock()
+
+	dec.buf.Reset() // In case data lingers from previous invocation.
+	dec.err = nil
+	id := dec.decodeTypeSequence(false)
+	if dec.err == nil {
+		dec.decodeValue(id, v)
+	}
+	return dec.err
+}
+
+// If debug.go is compiled into the program , debugFunc prints a human-readable
+// representation of the gob data read from r by calling that file's Debug function.
+// Otherwise it is nil.
+var debugFunc func(io.Reader)
diff --git a/libgo/go/encoding/gob/doc.go b/libgo/go/encoding/gob/doc.go
new file mode 100644
index 00000000000..05ebef19593
--- /dev/null
+++ b/libgo/go/encoding/gob/doc.go
@@ -0,0 +1,366 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+/*
+Package gob manages streams of gobs - binary values exchanged between an
+Encoder (transmitter) and a Decoder (receiver).  A typical use is transporting
+arguments and results of remote procedure calls (RPCs) such as those provided by
+package "rpc".
+
+A stream of gobs is self-describing.  Each data item in the stream is preceded by
+a specification of its type, expressed in terms of a small set of predefined
+types.  Pointers are not transmitted, but the things they point to are
+transmitted; that is, the values are flattened.  Recursive types work fine, but
+recursive values (data with cycles) are problematic.  This may change.
+
+To use gobs, create an Encoder and present it with a series of data items as
+values or addresses that can be dereferenced to values.  The Encoder makes sure
+all type information is sent before it is needed.  At the receive side, a
+Decoder retrieves values from the encoded stream and unpacks them into local
+variables.
+
+The source and destination values/types need not correspond exactly.  For structs,
+fields (identified by name) that are in the source but absent from the receiving
+variable will be ignored.  Fields that are in the receiving variable but missing
+from the transmitted type or value will be ignored in the destination.  If a field
+with the same name is present in both, their types must be compatible. Both the
+receiver and transmitter will do all necessary indirection and dereferencing to
+convert between gobs and actual Go values.  For instance, a gob type that is
+schematically,
+
+	struct { A, B int }
+
+can be sent from or received into any of these Go types:
+
+	struct { A, B int }	// the same
+	*struct { A, B int }	// extra indirection of the struct
+	struct { *A, **B int }	// extra indirection of the fields
+	struct { A, B int64 }	// different concrete value type; see below
+
+It may also be received into any of these:
+
+	struct { A, B int }	// the same
+	struct { B, A int }	// ordering doesn't matter; matching is by name
+	struct { A, B, C int }	// extra field (C) ignored
+	struct { B int }	// missing field (A) ignored; data will be dropped
+	struct { B, C int }	// missing field (A) ignored; extra field (C) ignored.
+
+Attempting to receive into these types will draw a decode error:
+
+	struct { A int; B uint }	// change of signedness for B
+	struct { A int; B float }	// change of type for B
+	struct { }			// no field names in common
+	struct { C, D int }		// no field names in common
+
+Integers are transmitted two ways: arbitrary precision signed integers or
+arbitrary precision unsigned integers.  There is no int8, int16 etc.
+discrimination in the gob format; there are only signed and unsigned integers.  As
+described below, the transmitter sends the value in a variable-length encoding;
+the receiver accepts the value and stores it in the destination variable.
+Floating-point numbers are always sent using IEEE-754 64-bit precision (see
+below).
+
+Signed integers may be received into any signed integer variable: int, int16, etc.;
+unsigned integers may be received into any unsigned integer variable; and floating
+point values may be received into any floating point variable.  However,
+the destination variable must be able to represent the value or the decode
+operation will fail.
+
+Structs, arrays and slices are also supported.  Strings and arrays of bytes are
+supported with a special, efficient representation (see below).  When a slice is
+decoded, if the existing slice has capacity the slice will be extended in place;
+if not, a new array is allocated.  Regardless, the length of the resuling slice
+reports the number of elements decoded.
+
+Functions and channels cannot be sent in a gob.  Attempting
+to encode a value that contains one will fail.
+
+The rest of this comment documents the encoding, details that are not important
+for most users.  Details are presented bottom-up.
+
+An unsigned integer is sent one of two ways.  If it is less than 128, it is sent
+as a byte with that value.  Otherwise it is sent as a minimal-length big-endian
+(high byte first) byte stream holding the value, preceded by one byte holding the
+byte count, negated.  Thus 0 is transmitted as (00), 7 is transmitted as (07) and
+256 is transmitted as (FE 01 00).
+
+A boolean is encoded within an unsigned integer: 0 for false, 1 for true.
+
+A signed integer, i, is encoded within an unsigned integer, u.  Within u, bits 1
+upward contain the value; bit 0 says whether they should be complemented upon
+receipt.  The encode algorithm looks like this:
+
+	uint u;
+	if i < 0 {
+		u = (^i << 1) | 1	// complement i, bit 0 is 1
+	} else {
+		u = (i << 1)	// do not complement i, bit 0 is 0
+	}
+	encodeUnsigned(u)
+
+The low bit is therefore analogous to a sign bit, but making it the complement bit
+instead guarantees that the largest negative integer is not a special case.  For
+example, -129=^128=(^256>>1) encodes as (FE 01 01).
+
+Floating-point numbers are always sent as a representation of a float64 value.
+That value is converted to a uint64 using math.Float64bits.  The uint64 is then
+byte-reversed and sent as a regular unsigned integer.  The byte-reversal means the
+exponent and high-precision part of the mantissa go first.  Since the low bits are
+often zero, this can save encoding bytes.  For instance, 17.0 is encoded in only
+three bytes (FE 31 40).
+
+Strings and slices of bytes are sent as an unsigned count followed by that many
+uninterpreted bytes of the value.
+
+All other slices and arrays are sent as an unsigned count followed by that many
+elements using the standard gob encoding for their type, recursively.
+
+Maps are sent as an unsigned count followed by that man key, element
+pairs. Empty but non-nil maps are sent, so if the sender has allocated
+a map, the receiver will allocate a map even no elements are
+transmitted.
+
+Structs are sent as a sequence of (field number, field value) pairs.  The field
+value is sent using the standard gob encoding for its type, recursively.  If a
+field has the zero value for its type, it is omitted from the transmission.  The
+field number is defined by the type of the encoded struct: the first field of the
+encoded type is field 0, the second is field 1, etc.  When encoding a value, the
+field numbers are delta encoded for efficiency and the fields are always sent in
+order of increasing field number; the deltas are therefore unsigned.  The
+initialization for the delta encoding sets the field number to -1, so an unsigned
+integer field 0 with value 7 is transmitted as unsigned delta = 1, unsigned value
+= 7 or (01 07).  Finally, after all the fields have been sent a terminating mark
+denotes the end of the struct.  That mark is a delta=0 value, which has
+representation (00).
+
+Interface types are not checked for compatibility; all interface types are
+treated, for transmission, as members of a single "interface" type, analogous to
+int or []byte - in effect they're all treated as interface{}.  Interface values
+are transmitted as a string identifying the concrete type being sent (a name
+that must be pre-defined by calling Register), followed by a byte count of the
+length of the following data (so the value can be skipped if it cannot be
+stored), followed by the usual encoding of concrete (dynamic) value stored in
+the interface value.  (A nil interface value is identified by the empty string
+and transmits no value.) Upon receipt, the decoder verifies that the unpacked
+concrete item satisfies the interface of the receiving variable.
+
+The representation of types is described below.  When a type is defined on a given
+connection between an Encoder and Decoder, it is assigned a signed integer type
+id.  When Encoder.Encode(v) is called, it makes sure there is an id assigned for
+the type of v and all its elements and then it sends the pair (typeid, encoded-v)
+where typeid is the type id of the encoded type of v and encoded-v is the gob
+encoding of the value v.
+
+To define a type, the encoder chooses an unused, positive type id and sends the
+pair (-type id, encoded-type) where encoded-type is the gob encoding of a wireType
+description, constructed from these types:
+
+	type wireType struct {
+		ArrayT  *ArrayType
+		SliceT  *SliceType
+		StructT *StructType
+		MapT    *MapType
+	}
+	type ArrayType struct {
+		CommonType
+		Elem typeId
+		Len  int
+	}
+	type CommonType struct {
+		Name string // the name of the struct type
+		Id  int    // the id of the type, repeated so it's inside the type
+	}
+	type SliceType struct {
+		CommonType
+		Elem typeId
+	}
+	type StructType struct {
+		CommonType
+		Field []*fieldType // the fields of the struct.
+	}
+	type FieldType struct {
+		Name string // the name of the field.
+		Id   int    // the type id of the field, which must be already defined
+	}
+	type MapType struct {
+		CommonType
+		Key  typeId
+		Elem typeId
+	}
+
+If there are nested type ids, the types for all inner type ids must be defined
+before the top-level type id is used to describe an encoded-v.
+
+For simplicity in setup, the connection is defined to understand these types a
+priori, as well as the basic gob types int, uint, etc.  Their ids are:
+
+	bool        1
+	int         2
+	uint        3
+	float       4
+	[]byte      5
+	string      6
+	complex     7
+	interface   8
+	// gap for reserved ids.
+	WireType    16
+	ArrayType   17
+	CommonType  18
+	SliceType   19
+	StructType  20
+	FieldType   21
+	// 22 is slice of fieldType.
+	MapType     23
+
+Finally, each message created by a call to Encode is preceded by an encoded
+unsigned integer count of the number of bytes remaining in the message.  After
+the initial type name, interface values are wrapped the same way; in effect, the
+interface value acts like a recursive invocation of Encode.
+
+In summary, a gob stream looks like
+
+	(byteCount (-type id, encoding of a wireType)* (type id, encoding of a value))*
+
+where * signifies zero or more repetitions and the type id of a value must
+be predefined or be defined before the value in the stream.
+
+See "Gobs of data" for a design discussion of the gob wire format:
+http://blog.golang.org/2011/03/gobs-of-data.html
+*/
+package gob
+
+/*
+Grammar:
+
+Tokens starting with a lower case letter are terminals; int(n)
+and uint(n) represent the signed/unsigned encodings of the value n.
+
+GobStream:
+	DelimitedMessage*
+DelimitedMessage:
+	uint(lengthOfMessage) Message
+Message:
+	TypeSequence TypedValue
+TypeSequence
+	(TypeDefinition DelimitedTypeDefinition*)?
+DelimitedTypeDefinition:
+	uint(lengthOfTypeDefinition) TypeDefinition
+TypedValue:
+	int(typeId) Value
+TypeDefinition:
+	int(-typeId) encodingOfWireType
+Value:
+	SingletonValue | StructValue
+SingletonValue:
+	uint(0) FieldValue
+FieldValue:
+	builtinValue | ArrayValue | MapValue | SliceValue | StructValue | InterfaceValue
+InterfaceValue:
+	NilInterfaceValue | NonNilInterfaceValue
+NilInterfaceValue:
+	uint(0)
+NonNilInterfaceValue:
+	ConcreteTypeName TypeSequence InterfaceContents
+ConcreteTypeName:
+	uint(lengthOfName) [already read=n] name
+InterfaceContents:
+	int(concreteTypeId) DelimitedValue
+DelimitedValue:
+	uint(length) Value
+ArrayValue:
+	uint(n) FieldValue*n [n elements]
+MapValue:
+	uint(n) (FieldValue FieldValue)*n  [n (key, value) pairs]
+SliceValue:
+	uint(n) FieldValue*n [n elements]
+StructValue:
+	(uint(fieldDelta) FieldValue)*
+*/
+
+/*
+For implementers and the curious, here is an encoded example.  Given
+	type Point struct {X, Y int}
+and the value
+	p := Point{22, 33}
+the bytes transmitted that encode p will be:
+	1f ff 81 03 01 01 05 50 6f 69 6e 74 01 ff 82 00
+	01 02 01 01 58 01 04 00 01 01 59 01 04 00 00 00
+	07 ff 82 01 2c 01 42 00
+They are determined as follows.
+
+Since this is the first transmission of type Point, the type descriptor
+for Point itself must be sent before the value.  This is the first type
+we've sent on this Encoder, so it has type id 65 (0 through 64 are
+reserved).
+
+	1f	// This item (a type descriptor) is 31 bytes long.
+	ff 81	// The negative of the id for the type we're defining, -65.
+		// This is one byte (indicated by FF = -1) followed by
+		// ^-65<<1 | 1.  The low 1 bit signals to complement the
+		// rest upon receipt.
+
+	// Now we send a type descriptor, which is itself a struct (wireType).
+	// The type of wireType itself is known (it's built in, as is the type of
+	// all its components), so we just need to send a *value* of type wireType
+	// that represents type "Point".
+	// Here starts the encoding of that value.
+	// Set the field number implicitly to -1; this is done at the beginning
+	// of every struct, including nested structs.
+	03	// Add 3 to field number; now 2 (wireType.structType; this is a struct).
+		// structType starts with an embedded commonType, which appears
+		// as a regular structure here too.
+	01	// add 1 to field number (now 0); start of embedded commonType.
+	01	// add 1 to field number (now 0, the name of the type)
+	05	// string is (unsigned) 5 bytes long
+	50 6f 69 6e 74	// wireType.structType.commonType.name = "Point"
+	01	// add 1 to field number (now 1, the id of the type)
+	ff 82	// wireType.structType.commonType._id = 65
+	00	// end of embedded wiretype.structType.commonType struct
+	01	// add 1 to field number (now 1, the field array in wireType.structType)
+	02	// There are two fields in the type (len(structType.field))
+	01	// Start of first field structure; add 1 to get field number 0: field[0].name
+	01	// 1 byte
+	58	// structType.field[0].name = "X"
+	01	// Add 1 to get field number 1: field[0].id
+	04	// structType.field[0].typeId is 2 (signed int).
+	00	// End of structType.field[0]; start structType.field[1]; set field number to -1.
+	01	// Add 1 to get field number 0: field[1].name
+	01	// 1 byte
+	59	// structType.field[1].name = "Y"
+	01	// Add 1 to get field number 1: field[0].id
+	04	// struct.Type.field[1].typeId is 2 (signed int).
+	00	// End of structType.field[1]; end of structType.field.
+	00	// end of wireType.structType structure
+	00	// end of wireType structure
+
+Now we can send the Point value.  Again the field number resets to -1:
+
+	07	// this value is 7 bytes long
+	ff 82	// the type number, 65 (1 byte (-FF) followed by 65<<1)
+	01	// add one to field number, yielding field 0
+	2c	// encoding of signed "22" (0x22 = 44 = 22<<1); Point.x = 22
+	01	// add one to field number, yielding field 1
+	42	// encoding of signed "33" (0x42 = 66 = 33<<1); Point.y = 33
+	00	// end of structure
+
+The type encoding is long and fairly intricate but we send it only once.
+If p is transmitted a second time, the type is already known so the
+output will be just:
+
+	07 ff 82 01 2c 01 42 00
+
+A single non-struct value at top level is transmitted like a field with
+delta tag 0.  For instance, a signed integer with value 3 presented as
+the argument to Encode will emit:
+
+	03 04 00 06
+
+Which represents:
+
+	03	// this value is 3 bytes long
+	04	// the type number, 2, represents an integer
+	00	// tag delta 0
+	06	// value 3
+
+*/
diff --git a/libgo/go/encoding/gob/dump.go b/libgo/go/encoding/gob/dump.go
new file mode 100644
index 00000000000..0d0017cc783
--- /dev/null
+++ b/libgo/go/encoding/gob/dump.go
@@ -0,0 +1,22 @@
+package main
+
+// Need to compile package gob with debug.go to build this program.
+
+import (
+	"encoding/gob"
+	"fmt"
+	"os"
+)
+
+func main() {
+	var err error
+	file := os.Stdin
+	if len(os.Args) > 1 {
+		file, err = os.Open(os.Args[1])
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "dump: %s\n", err)
+			os.Exit(1)
+		}
+	}
+	gob.Debug(file)
+}
diff --git a/libgo/go/encoding/gob/encode.go b/libgo/go/encoding/gob/encode.go
new file mode 100644
index 00000000000..c7e48230c53
--- /dev/null
+++ b/libgo/go/encoding/gob/encode.go
@@ -0,0 +1,717 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package gob
+
+import (
+	"bytes"
+	"math"
+	"reflect"
+	"unsafe"
+)
+
+const uint64Size = int(unsafe.Sizeof(uint64(0)))
+
+// encoderState is the global execution state of an instance of the encoder.
+// Field numbers are delta encoded and always increase. The field
+// number is initialized to -1 so 0 comes out as delta(1). A delta of
+// 0 terminates the structure.
+type encoderState struct {
+	enc      *Encoder
+	b        *bytes.Buffer
+	sendZero bool                 // encoding an array element or map key/value pair; send zero values
+	fieldnum int                  // the last field number written.
+	buf      [1 + uint64Size]byte // buffer used by the encoder; here to avoid allocation.
+	next     *encoderState        // for free list
+}
+
+func (enc *Encoder) newEncoderState(b *bytes.Buffer) *encoderState {
+	e := enc.freeList
+	if e == nil {
+		e = new(encoderState)
+		e.enc = enc
+	} else {
+		enc.freeList = e.next
+	}
+	e.sendZero = false
+	e.fieldnum = 0
+	e.b = b
+	return e
+}
+
+func (enc *Encoder) freeEncoderState(e *encoderState) {
+	e.next = enc.freeList
+	enc.freeList = e
+}
+
+// Unsigned integers have a two-state encoding.  If the number is less
+// than 128 (0 through 0x7F), its value is written directly.
+// Otherwise the value is written in big-endian byte order preceded
+// by the byte length, negated.
+
+// encodeUint writes an encoded unsigned integer to state.b.
+func (state *encoderState) encodeUint(x uint64) {
+	if x <= 0x7F {
+		err := state.b.WriteByte(uint8(x))
+		if err != nil {
+			error_(err)
+		}
+		return
+	}
+	i := uint64Size
+	for x > 0 {
+		state.buf[i] = uint8(x)
+		x >>= 8
+		i--
+	}
+	state.buf[i] = uint8(i - uint64Size) // = loop count, negated
+	_, err := state.b.Write(state.buf[i : uint64Size+1])
+	if err != nil {
+		error_(err)
+	}
+}
+
+// encodeInt writes an encoded signed integer to state.w.
+// The low bit of the encoding says whether to bit complement the (other bits of the)
+// uint to recover the int.
+func (state *encoderState) encodeInt(i int64) {
+	var x uint64
+	if i < 0 {
+		x = uint64(^i<<1) | 1
+	} else {
+		x = uint64(i << 1)
+	}
+	state.encodeUint(uint64(x))
+}
+
+// encOp is the signature of an encoding operator for a given type.
+type encOp func(i *encInstr, state *encoderState, p unsafe.Pointer)
+
+// The 'instructions' of the encoding machine
+type encInstr struct {
+	op     encOp
+	field  int     // field number
+	indir  int     // how many pointer indirections to reach the value in the struct
+	offset uintptr // offset in the structure of the field to encode
+}
+
+// update emits a field number and updates the state to record its value for delta encoding.
+// If the instruction pointer is nil, it does nothing
+func (state *encoderState) update(instr *encInstr) {
+	if instr != nil {
+		state.encodeUint(uint64(instr.field - state.fieldnum))
+		state.fieldnum = instr.field
+	}
+}
+
+// Each encoder for a composite is responsible for handling any
+// indirections associated with the elements of the data structure.
+// If any pointer so reached is nil, no bytes are written.  If the
+// data item is zero, no bytes are written.  Single values - ints,
+// strings etc. - are indirected before calling their encoders.
+// Otherwise, the output (for a scalar) is the field number, as an
+// encoded integer, followed by the field data in its appropriate
+// format.
+
+// encIndirect dereferences p indir times and returns the result.
+func encIndirect(p unsafe.Pointer, indir int) unsafe.Pointer {
+	for ; indir > 0; indir-- {
+		p = *(*unsafe.Pointer)(p)
+		if p == nil {
+			return unsafe.Pointer(nil)
+		}
+	}
+	return p
+}
+
+// encBool encodes the bool with address p as an unsigned 0 or 1.
+func encBool(i *encInstr, state *encoderState, p unsafe.Pointer) {
+	b := *(*bool)(p)
+	if b || state.sendZero {
+		state.update(i)
+		if b {
+			state.encodeUint(1)
+		} else {
+			state.encodeUint(0)
+		}
+	}
+}
+
+// encInt encodes the int with address p.
+func encInt(i *encInstr, state *encoderState, p unsafe.Pointer) {
+	v := int64(*(*int)(p))
+	if v != 0 || state.sendZero {
+		state.update(i)
+		state.encodeInt(v)
+	}
+}
+
+// encUint encodes the uint with address p.
+func encUint(i *encInstr, state *encoderState, p unsafe.Pointer) {
+	v := uint64(*(*uint)(p))
+	if v != 0 || state.sendZero {
+		state.update(i)
+		state.encodeUint(v)
+	}
+}
+
+// encInt8 encodes the int8 with address p.
+func encInt8(i *encInstr, state *encoderState, p unsafe.Pointer) {
+	v := int64(*(*int8)(p))
+	if v != 0 || state.sendZero {
+		state.update(i)
+		state.encodeInt(v)
+	}
+}
+
+// encUint8 encodes the uint8 with address p.
+func encUint8(i *encInstr, state *encoderState, p unsafe.Pointer) {
+	v := uint64(*(*uint8)(p))
+	if v != 0 || state.sendZero {
+		state.update(i)
+		state.encodeUint(v)
+	}
+}
+
+// encInt16 encodes the int16 with address p.
+func encInt16(i *encInstr, state *encoderState, p unsafe.Pointer) {
+	v := int64(*(*int16)(p))
+	if v != 0 || state.sendZero {
+		state.update(i)
+		state.encodeInt(v)
+	}
+}
+
+// encUint16 encodes the uint16 with address p.
+func encUint16(i *encInstr, state *encoderState, p unsafe.Pointer) {
+	v := uint64(*(*uint16)(p))
+	if v != 0 || state.sendZero {
+		state.update(i)
+		state.encodeUint(v)
+	}
+}
+
+// encInt32 encodes the int32 with address p.
+func encInt32(i *encInstr, state *encoderState, p unsafe.Pointer) {
+	v := int64(*(*int32)(p))
+	if v != 0 || state.sendZero {
+		state.update(i)
+		state.encodeInt(v)
+	}
+}
+
+// encUint encodes the uint32 with address p.
+func encUint32(i *encInstr, state *encoderState, p unsafe.Pointer) {
+	v := uint64(*(*uint32)(p))
+	if v != 0 || state.sendZero {
+		state.update(i)
+		state.encodeUint(v)
+	}
+}
+
+// encInt64 encodes the int64 with address p.
+func encInt64(i *encInstr, state *encoderState, p unsafe.Pointer) {
+	v := *(*int64)(p)
+	if v != 0 || state.sendZero {
+		state.update(i)
+		state.encodeInt(v)
+	}
+}
+
+// encInt64 encodes the uint64 with address p.
+func encUint64(i *encInstr, state *encoderState, p unsafe.Pointer) {
+	v := *(*uint64)(p)
+	if v != 0 || state.sendZero {
+		state.update(i)
+		state.encodeUint(v)
+	}
+}
+
+// encUintptr encodes the uintptr with address p.
+func encUintptr(i *encInstr, state *encoderState, p unsafe.Pointer) {
+	v := uint64(*(*uintptr)(p))
+	if v != 0 || state.sendZero {
+		state.update(i)
+		state.encodeUint(v)
+	}
+}
+
+// floatBits returns a uint64 holding the bits of a floating-point number.
+// Floating-point numbers are transmitted as uint64s holding the bits
+// of the underlying representation.  They are sent byte-reversed, with
+// the exponent end coming out first, so integer floating point numbers
+// (for example) transmit more compactly.  This routine does the
+// swizzling.
+func floatBits(f float64) uint64 {
+	u := math.Float64bits(f)
+	var v uint64
+	for i := 0; i < 8; i++ {
+		v <<= 8
+		v |= u & 0xFF
+		u >>= 8
+	}
+	return v
+}
+
+// encFloat32 encodes the float32 with address p.
+func encFloat32(i *encInstr, state *encoderState, p unsafe.Pointer) {
+	f := *(*float32)(p)
+	if f != 0 || state.sendZero {
+		v := floatBits(float64(f))
+		state.update(i)
+		state.encodeUint(v)
+	}
+}
+
+// encFloat64 encodes the float64 with address p.
+func encFloat64(i *encInstr, state *encoderState, p unsafe.Pointer) {
+	f := *(*float64)(p)
+	if f != 0 || state.sendZero {
+		state.update(i)
+		v := floatBits(f)
+		state.encodeUint(v)
+	}
+}
+
+// encComplex64 encodes the complex64 with address p.
+// Complex numbers are just a pair of floating-point numbers, real part first.
+func encComplex64(i *encInstr, state *encoderState, p unsafe.Pointer) {
+	c := *(*complex64)(p)
+	if c != 0+0i || state.sendZero {
+		rpart := floatBits(float64(real(c)))
+		ipart := floatBits(float64(imag(c)))
+		state.update(i)
+		state.encodeUint(rpart)
+		state.encodeUint(ipart)
+	}
+}
+
+// encComplex128 encodes the complex128 with address p.
+func encComplex128(i *encInstr, state *encoderState, p unsafe.Pointer) {
+	c := *(*complex128)(p)
+	if c != 0+0i || state.sendZero {
+		rpart := floatBits(real(c))
+		ipart := floatBits(imag(c))
+		state.update(i)
+		state.encodeUint(rpart)
+		state.encodeUint(ipart)
+	}
+}
+
+// encUint8Array encodes the byte slice whose header has address p.
+// Byte arrays are encoded as an unsigned count followed by the raw bytes.
+func encUint8Array(i *encInstr, state *encoderState, p unsafe.Pointer) {
+	b := *(*[]byte)(p)
+	if len(b) > 0 || state.sendZero {
+		state.update(i)
+		state.encodeUint(uint64(len(b)))
+		state.b.Write(b)
+	}
+}
+
+// encString encodes the string whose header has address p.
+// Strings are encoded as an unsigned count followed by the raw bytes.
+func encString(i *encInstr, state *encoderState, p unsafe.Pointer) {
+	s := *(*string)(p)
+	if len(s) > 0 || state.sendZero {
+		state.update(i)
+		state.encodeUint(uint64(len(s)))
+		state.b.WriteString(s)
+	}
+}
+
+// encStructTerminator encodes the end of an encoded struct
+// as delta field number of 0.
+func encStructTerminator(i *encInstr, state *encoderState, p unsafe.Pointer) {
+	state.encodeUint(0)
+}
+
+// Execution engine
+
+// encEngine an array of instructions indexed by field number of the encoding
+// data, typically a struct.  It is executed top to bottom, walking the struct.
+type encEngine struct {
+	instr []encInstr
+}
+
+const singletonField = 0
+
+// encodeSingle encodes a single top-level non-struct value.
+func (enc *Encoder) encodeSingle(b *bytes.Buffer, engine *encEngine, basep uintptr) {
+	state := enc.newEncoderState(b)
+	state.fieldnum = singletonField
+	// There is no surrounding struct to frame the transmission, so we must
+	// generate data even if the item is zero.  To do this, set sendZero.
+	state.sendZero = true
+	instr := &engine.instr[singletonField]
+	p := unsafe.Pointer(basep) // offset will be zero
+	if instr.indir > 0 {
+		if p = encIndirect(p, instr.indir); p == nil {
+			return
+		}
+	}
+	instr.op(instr, state, p)
+	enc.freeEncoderState(state)
+}
+
+// encodeStruct encodes a single struct value.
+func (enc *Encoder) encodeStruct(b *bytes.Buffer, engine *encEngine, basep uintptr) {
+	state := enc.newEncoderState(b)
+	state.fieldnum = -1
+	for i := 0; i < len(engine.instr); i++ {
+		instr := &engine.instr[i]
+		p := unsafe.Pointer(basep + instr.offset)
+		if instr.indir > 0 {
+			if p = encIndirect(p, instr.indir); p == nil {
+				continue
+			}
+		}
+		instr.op(instr, state, p)
+	}
+	enc.freeEncoderState(state)
+}
+
+// encodeArray encodes the array whose 0th element is at p.
+func (enc *Encoder) encodeArray(b *bytes.Buffer, p uintptr, op encOp, elemWid uintptr, elemIndir int, length int) {
+	state := enc.newEncoderState(b)
+	state.fieldnum = -1
+	state.sendZero = true
+	state.encodeUint(uint64(length))
+	for i := 0; i < length; i++ {
+		elemp := p
+		up := unsafe.Pointer(elemp)
+		if elemIndir > 0 {
+			if up = encIndirect(up, elemIndir); up == nil {
+				errorf("encodeArray: nil element")
+			}
+			elemp = uintptr(up)
+		}
+		op(nil, state, unsafe.Pointer(elemp))
+		p += uintptr(elemWid)
+	}
+	enc.freeEncoderState(state)
+}
+
+// encodeReflectValue is a helper for maps. It encodes the value v.
+func encodeReflectValue(state *encoderState, v reflect.Value, op encOp, indir int) {
+	for i := 0; i < indir && v.IsValid(); i++ {
+		v = reflect.Indirect(v)
+	}
+	if !v.IsValid() {
+		errorf("encodeReflectValue: nil element")
+	}
+	op(nil, state, unsafe.Pointer(unsafeAddr(v)))
+}
+
+// encodeMap encodes a map as unsigned count followed by key:value pairs.
+// Because map internals are not exposed, we must use reflection rather than
+// addresses.
+func (enc *Encoder) encodeMap(b *bytes.Buffer, mv reflect.Value, keyOp, elemOp encOp, keyIndir, elemIndir int) {
+	state := enc.newEncoderState(b)
+	state.fieldnum = -1
+	state.sendZero = true
+	keys := mv.MapKeys()
+	state.encodeUint(uint64(len(keys)))
+	for _, key := range keys {
+		encodeReflectValue(state, key, keyOp, keyIndir)
+		encodeReflectValue(state, mv.MapIndex(key), elemOp, elemIndir)
+	}
+	enc.freeEncoderState(state)
+}
+
+// encodeInterface encodes the interface value iv.
+// To send an interface, we send a string identifying the concrete type, followed
+// by the type identifier (which might require defining that type right now), followed
+// by the concrete value.  A nil value gets sent as the empty string for the name,
+// followed by no value.
+func (enc *Encoder) encodeInterface(b *bytes.Buffer, iv reflect.Value) {
+	state := enc.newEncoderState(b)
+	state.fieldnum = -1
+	state.sendZero = true
+	if iv.IsNil() {
+		state.encodeUint(0)
+		return
+	}
+
+	ut := userType(iv.Elem().Type())
+	name, ok := concreteTypeToName[ut.base]
+	if !ok {
+		errorf("type not registered for interface: %s", ut.base)
+	}
+	// Send the name.
+	state.encodeUint(uint64(len(name)))
+	_, err := state.b.WriteString(name)
+	if err != nil {
+		error_(err)
+	}
+	// Define the type id if necessary.
+	enc.sendTypeDescriptor(enc.writer(), state, ut)
+	// Send the type id.
+	enc.sendTypeId(state, ut)
+	// Encode the value into a new buffer.  Any nested type definitions
+	// should be written to b, before the encoded value.
+	enc.pushWriter(b)
+	data := new(bytes.Buffer)
+	data.Write(spaceForLength)
+	enc.encode(data, iv.Elem(), ut)
+	if enc.err != nil {
+		error_(enc.err)
+	}
+	enc.popWriter()
+	enc.writeMessage(b, data)
+	if enc.err != nil {
+		error_(err)
+	}
+	enc.freeEncoderState(state)
+}
+
+// isZero returns whether the value is the zero of its type.
+func isZero(val reflect.Value) bool {
+	switch val.Kind() {
+	case reflect.Array, reflect.Map, reflect.Slice, reflect.String:
+		return val.Len() == 0
+	case reflect.Bool:
+		return !val.Bool()
+	case reflect.Complex64, reflect.Complex128:
+		return val.Complex() == 0
+	case reflect.Chan, reflect.Func, reflect.Ptr:
+		return val.IsNil()
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		return val.Int() == 0
+	case reflect.Float32, reflect.Float64:
+		return val.Float() == 0
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+		return val.Uint() == 0
+	}
+	panic("unknown type in isZero " + val.Type().String())
+}
+
+// encGobEncoder encodes a value that implements the GobEncoder interface.
+// The data is sent as a byte array.
+func (enc *Encoder) encodeGobEncoder(b *bytes.Buffer, v reflect.Value) {
+	// TODO: should we catch panics from the called method?
+	// We know it's a GobEncoder, so just call the method directly.
+	data, err := v.Interface().(GobEncoder).GobEncode()
+	if err != nil {
+		error_(err)
+	}
+	state := enc.newEncoderState(b)
+	state.fieldnum = -1
+	state.encodeUint(uint64(len(data)))
+	state.b.Write(data)
+	enc.freeEncoderState(state)
+}
+
+var encOpTable = [...]encOp{
+	reflect.Bool:       encBool,
+	reflect.Int:        encInt,
+	reflect.Int8:       encInt8,
+	reflect.Int16:      encInt16,
+	reflect.Int32:      encInt32,
+	reflect.Int64:      encInt64,
+	reflect.Uint:       encUint,
+	reflect.Uint8:      encUint8,
+	reflect.Uint16:     encUint16,
+	reflect.Uint32:     encUint32,
+	reflect.Uint64:     encUint64,
+	reflect.Uintptr:    encUintptr,
+	reflect.Float32:    encFloat32,
+	reflect.Float64:    encFloat64,
+	reflect.Complex64:  encComplex64,
+	reflect.Complex128: encComplex128,
+	reflect.String:     encString,
+}
+
+// encOpFor returns (a pointer to) the encoding op for the base type under rt and
+// the indirection count to reach it.
+func (enc *Encoder) encOpFor(rt reflect.Type, inProgress map[reflect.Type]*encOp) (*encOp, int) {
+	ut := userType(rt)
+	// If the type implements GobEncoder, we handle it without further processing.
+	if ut.isGobEncoder {
+		return enc.gobEncodeOpFor(ut)
+	}
+	// If this type is already in progress, it's a recursive type (e.g. map[string]*T).
+	// Return the pointer to the op we're already building.
+	if opPtr := inProgress[rt]; opPtr != nil {
+		return opPtr, ut.indir
+	}
+	typ := ut.base
+	indir := ut.indir
+	k := typ.Kind()
+	var op encOp
+	if int(k) < len(encOpTable) {
+		op = encOpTable[k]
+	}
+	if op == nil {
+		inProgress[rt] = &op
+		// Special cases
+		switch t := typ; t.Kind() {
+		case reflect.Slice:
+			if t.Elem().Kind() == reflect.Uint8 {
+				op = encUint8Array
+				break
+			}
+			// Slices have a header; we decode it to find the underlying array.
+			elemOp, indir := enc.encOpFor(t.Elem(), inProgress)
+			op = func(i *encInstr, state *encoderState, p unsafe.Pointer) {
+				slice := (*reflect.SliceHeader)(p)
+				if !state.sendZero && slice.Len == 0 {
+					return
+				}
+				state.update(i)
+				state.enc.encodeArray(state.b, slice.Data, *elemOp, t.Elem().Size(), indir, int(slice.Len))
+			}
+		case reflect.Array:
+			// True arrays have size in the type.
+			elemOp, indir := enc.encOpFor(t.Elem(), inProgress)
+			op = func(i *encInstr, state *encoderState, p unsafe.Pointer) {
+				state.update(i)
+				state.enc.encodeArray(state.b, uintptr(p), *elemOp, t.Elem().Size(), indir, t.Len())
+			}
+		case reflect.Map:
+			keyOp, keyIndir := enc.encOpFor(t.Key(), inProgress)
+			elemOp, elemIndir := enc.encOpFor(t.Elem(), inProgress)
+			op = func(i *encInstr, state *encoderState, p unsafe.Pointer) {
+				// Maps cannot be accessed by moving addresses around the way
+				// that slices etc. can.  We must recover a full reflection value for
+				// the iteration.
+				v := reflect.ValueOf(unsafe.Unreflect(t, unsafe.Pointer(p)))
+				mv := reflect.Indirect(v)
+				// We send zero-length (but non-nil) maps because the
+				// receiver might want to use the map.  (Maps don't use append.)
+				if !state.sendZero && mv.IsNil() {
+					return
+				}
+				state.update(i)
+				state.enc.encodeMap(state.b, mv, *keyOp, *elemOp, keyIndir, elemIndir)
+			}
+		case reflect.Struct:
+			// Generate a closure that calls out to the engine for the nested type.
+			enc.getEncEngine(userType(typ))
+			info := mustGetTypeInfo(typ)
+			op = func(i *encInstr, state *encoderState, p unsafe.Pointer) {
+				state.update(i)
+				// indirect through info to delay evaluation for recursive structs
+				state.enc.encodeStruct(state.b, info.encoder, uintptr(p))
+			}
+		case reflect.Interface:
+			op = func(i *encInstr, state *encoderState, p unsafe.Pointer) {
+				// Interfaces transmit the name and contents of the concrete
+				// value they contain.
+				v := reflect.ValueOf(unsafe.Unreflect(t, unsafe.Pointer(p)))
+				iv := reflect.Indirect(v)
+				if !state.sendZero && (!iv.IsValid() || iv.IsNil()) {
+					return
+				}
+				state.update(i)
+				state.enc.encodeInterface(state.b, iv)
+			}
+		}
+	}
+	if op == nil {
+		errorf("can't happen: encode type %s", rt)
+	}
+	return &op, indir
+}
+
+// gobEncodeOpFor returns the op for a type that is known to implement
+// GobEncoder.
+func (enc *Encoder) gobEncodeOpFor(ut *userTypeInfo) (*encOp, int) {
+	rt := ut.user
+	if ut.encIndir == -1 {
+		rt = reflect.PtrTo(rt)
+	} else if ut.encIndir > 0 {
+		for i := int8(0); i < ut.encIndir; i++ {
+			rt = rt.Elem()
+		}
+	}
+	var op encOp
+	op = func(i *encInstr, state *encoderState, p unsafe.Pointer) {
+		var v reflect.Value
+		if ut.encIndir == -1 {
+			// Need to climb up one level to turn value into pointer.
+			v = reflect.ValueOf(unsafe.Unreflect(rt, unsafe.Pointer(&p)))
+		} else {
+			v = reflect.ValueOf(unsafe.Unreflect(rt, p))
+		}
+		if !state.sendZero && isZero(v) {
+			return
+		}
+		state.update(i)
+		state.enc.encodeGobEncoder(state.b, v)
+	}
+	return &op, int(ut.encIndir) // encIndir: op will get called with p == address of receiver.
+}
+
+// compileEnc returns the engine to compile the type.
+func (enc *Encoder) compileEnc(ut *userTypeInfo) *encEngine {
+	srt := ut.base
+	engine := new(encEngine)
+	seen := make(map[reflect.Type]*encOp)
+	rt := ut.base
+	if ut.isGobEncoder {
+		rt = ut.user
+	}
+	if !ut.isGobEncoder &&
+		srt.Kind() == reflect.Struct {
+		for fieldNum, wireFieldNum := 0, 0; fieldNum < srt.NumField(); fieldNum++ {
+			f := srt.Field(fieldNum)
+			if !isExported(f.Name) {
+				continue
+			}
+			op, indir := enc.encOpFor(f.Type, seen)
+			engine.instr = append(engine.instr, encInstr{*op, wireFieldNum, indir, uintptr(f.Offset)})
+			wireFieldNum++
+		}
+		if srt.NumField() > 0 && len(engine.instr) == 0 {
+			errorf("type %s has no exported fields", rt)
+		}
+		engine.instr = append(engine.instr, encInstr{encStructTerminator, 0, 0, 0})
+	} else {
+		engine.instr = make([]encInstr, 1)
+		op, indir := enc.encOpFor(rt, seen)
+		engine.instr[0] = encInstr{*op, singletonField, indir, 0} // offset is zero
+	}
+	return engine
+}
+
+// getEncEngine returns the engine to compile the type.
+// typeLock must be held (or we're in initialization and guaranteed single-threaded).
+func (enc *Encoder) getEncEngine(ut *userTypeInfo) *encEngine {
+	info, err1 := getTypeInfo(ut)
+	if err1 != nil {
+		error_(err1)
+	}
+	if info.encoder == nil {
+		// mark this engine as underway before compiling to handle recursive types.
+		info.encoder = new(encEngine)
+		info.encoder = enc.compileEnc(ut)
+	}
+	return info.encoder
+}
+
+// lockAndGetEncEngine is a function that locks and compiles.
+// This lets us hold the lock only while compiling, not when encoding.
+func (enc *Encoder) lockAndGetEncEngine(ut *userTypeInfo) *encEngine {
+	typeLock.Lock()
+	defer typeLock.Unlock()
+	return enc.getEncEngine(ut)
+}
+
+func (enc *Encoder) encode(b *bytes.Buffer, value reflect.Value, ut *userTypeInfo) {
+	defer catchError(&enc.err)
+	engine := enc.lockAndGetEncEngine(ut)
+	indir := ut.indir
+	if ut.isGobEncoder {
+		indir = int(ut.encIndir)
+	}
+	for i := 0; i < indir; i++ {
+		value = reflect.Indirect(value)
+	}
+	if !ut.isGobEncoder && value.Type().Kind() == reflect.Struct {
+		enc.encodeStruct(b, engine, unsafeAddr(value))
+	} else {
+		enc.encodeSingle(b, engine, unsafeAddr(value))
+	}
+}
diff --git a/libgo/go/encoding/gob/encoder.go b/libgo/go/encoding/gob/encoder.go
new file mode 100644
index 00000000000..e4a48dfc4fc
--- /dev/null
+++ b/libgo/go/encoding/gob/encoder.go
@@ -0,0 +1,251 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package gob
+
+import (
+	"bytes"
+	"errors"
+	"io"
+	"reflect"
+	"sync"
+)
+
+// An Encoder manages the transmission of type and data information to the
+// other side of a connection.
+type Encoder struct {
+	mutex      sync.Mutex              // each item must be sent atomically
+	w          []io.Writer             // where to send the data
+	sent       map[reflect.Type]typeId // which types we've already sent
+	countState *encoderState           // stage for writing counts
+	freeList   *encoderState           // list of free encoderStates; avoids reallocation
+	byteBuf    bytes.Buffer            // buffer for top-level encoderState
+	err        error
+}
+
+// Before we encode a message, we reserve space at the head of the
+// buffer in which to encode its length. This means we can use the
+// buffer to assemble the message without another allocation.
+const maxLength = 9 // Maximum size of an encoded length.
+var spaceForLength = make([]byte, maxLength)
+
+// NewEncoder returns a new encoder that will transmit on the io.Writer.
+func NewEncoder(w io.Writer) *Encoder {
+	enc := new(Encoder)
+	enc.w = []io.Writer{w}
+	enc.sent = make(map[reflect.Type]typeId)
+	enc.countState = enc.newEncoderState(new(bytes.Buffer))
+	return enc
+}
+
+// writer() returns the innermost writer the encoder is using
+func (enc *Encoder) writer() io.Writer {
+	return enc.w[len(enc.w)-1]
+}
+
+// pushWriter adds a writer to the encoder.
+func (enc *Encoder) pushWriter(w io.Writer) {
+	enc.w = append(enc.w, w)
+}
+
+// popWriter pops the innermost writer.
+func (enc *Encoder) popWriter() {
+	enc.w = enc.w[0 : len(enc.w)-1]
+}
+
+func (enc *Encoder) badType(rt reflect.Type) {
+	enc.setError(errors.New("gob: can't encode type " + rt.String()))
+}
+
+func (enc *Encoder) setError(err error) {
+	if enc.err == nil { // remember the first.
+		enc.err = err
+	}
+}
+
+// writeMessage sends the data item preceded by a unsigned count of its length.
+func (enc *Encoder) writeMessage(w io.Writer, b *bytes.Buffer) {
+	// Space has been reserved for the length at the head of the message.
+	// This is a little dirty: we grab the slice from the bytes.Buffer and massage
+	// it by hand.
+	message := b.Bytes()
+	messageLen := len(message) - maxLength
+	// Encode the length.
+	enc.countState.b.Reset()
+	enc.countState.encodeUint(uint64(messageLen))
+	// Copy the length to be a prefix of the message.
+	offset := maxLength - enc.countState.b.Len()
+	copy(message[offset:], enc.countState.b.Bytes())
+	// Write the data.
+	_, err := w.Write(message[offset:])
+	// Drain the buffer and restore the space at the front for the count of the next message.
+	b.Reset()
+	b.Write(spaceForLength)
+	if err != nil {
+		enc.setError(err)
+	}
+}
+
+// sendActualType sends the requested type, without further investigation, unless
+// it's been sent before.
+func (enc *Encoder) sendActualType(w io.Writer, state *encoderState, ut *userTypeInfo, actual reflect.Type) (sent bool) {
+	if _, alreadySent := enc.sent[actual]; alreadySent {
+		return false
+	}
+	typeLock.Lock()
+	info, err := getTypeInfo(ut)
+	typeLock.Unlock()
+	if err != nil {
+		enc.setError(err)
+		return
+	}
+	// Send the pair (-id, type)
+	// Id:
+	state.encodeInt(-int64(info.id))
+	// Type:
+	enc.encode(state.b, reflect.ValueOf(info.wire), wireTypeUserInfo)
+	enc.writeMessage(w, state.b)
+	if enc.err != nil {
+		return
+	}
+
+	// Remember we've sent this type, both what the user gave us and the base type.
+	enc.sent[ut.base] = info.id
+	if ut.user != ut.base {
+		enc.sent[ut.user] = info.id
+	}
+	// Now send the inner types
+	switch st := actual; st.Kind() {
+	case reflect.Struct:
+		for i := 0; i < st.NumField(); i++ {
+			enc.sendType(w, state, st.Field(i).Type)
+		}
+	case reflect.Array, reflect.Slice:
+		enc.sendType(w, state, st.Elem())
+	case reflect.Map:
+		enc.sendType(w, state, st.Key())
+		enc.sendType(w, state, st.Elem())
+	}
+	return true
+}
+
+// sendType sends the type info to the other side, if necessary. 
+func (enc *Encoder) sendType(w io.Writer, state *encoderState, origt reflect.Type) (sent bool) {
+	ut := userType(origt)
+	if ut.isGobEncoder {
+		// The rules are different: regardless of the underlying type's representation,
+		// we need to tell the other side that this exact type is a GobEncoder.
+		return enc.sendActualType(w, state, ut, ut.user)
+	}
+
+	// It's a concrete value, so drill down to the base type.
+	switch rt := ut.base; rt.Kind() {
+	default:
+		// Basic types and interfaces do not need to be described.
+		return
+	case reflect.Slice:
+		// If it's []uint8, don't send; it's considered basic.
+		if rt.Elem().Kind() == reflect.Uint8 {
+			return
+		}
+		// Otherwise we do send.
+		break
+	case reflect.Array:
+		// arrays must be sent so we know their lengths and element types.
+		break
+	case reflect.Map:
+		// maps must be sent so we know their lengths and key/value types.
+		break
+	case reflect.Struct:
+		// structs must be sent so we know their fields.
+		break
+	case reflect.Chan, reflect.Func:
+		// Probably a bad field in a struct.
+		enc.badType(rt)
+		return
+	}
+
+	return enc.sendActualType(w, state, ut, ut.base)
+}
+
+// Encode transmits the data item represented by the empty interface value,
+// guaranteeing that all necessary type information has been transmitted first.
+func (enc *Encoder) Encode(e interface{}) error {
+	return enc.EncodeValue(reflect.ValueOf(e))
+}
+
+// sendTypeDescriptor makes sure the remote side knows about this type.
+// It will send a descriptor if this is the first time the type has been
+// sent.
+func (enc *Encoder) sendTypeDescriptor(w io.Writer, state *encoderState, ut *userTypeInfo) {
+	// Make sure the type is known to the other side.
+	// First, have we already sent this type?
+	rt := ut.base
+	if ut.isGobEncoder {
+		rt = ut.user
+	}
+	if _, alreadySent := enc.sent[rt]; !alreadySent {
+		// No, so send it.
+		sent := enc.sendType(w, state, rt)
+		if enc.err != nil {
+			return
+		}
+		// If the type info has still not been transmitted, it means we have
+		// a singleton basic type (int, []byte etc.) at top level.  We don't
+		// need to send the type info but we do need to update enc.sent.
+		if !sent {
+			typeLock.Lock()
+			info, err := getTypeInfo(ut)
+			typeLock.Unlock()
+			if err != nil {
+				enc.setError(err)
+				return
+			}
+			enc.sent[rt] = info.id
+		}
+	}
+}
+
+// sendTypeId sends the id, which must have already been defined.
+func (enc *Encoder) sendTypeId(state *encoderState, ut *userTypeInfo) {
+	// Identify the type of this top-level value.
+	state.encodeInt(int64(enc.sent[ut.base]))
+}
+
+// EncodeValue transmits the data item represented by the reflection value,
+// guaranteeing that all necessary type information has been transmitted first.
+func (enc *Encoder) EncodeValue(value reflect.Value) error {
+	// Make sure we're single-threaded through here, so multiple
+	// goroutines can share an encoder.
+	enc.mutex.Lock()
+	defer enc.mutex.Unlock()
+
+	// Remove any nested writers remaining due to previous errors.
+	enc.w = enc.w[0:1]
+
+	ut, err := validUserType(value.Type())
+	if err != nil {
+		return err
+	}
+
+	enc.err = nil
+	enc.byteBuf.Reset()
+	enc.byteBuf.Write(spaceForLength)
+	state := enc.newEncoderState(&enc.byteBuf)
+
+	enc.sendTypeDescriptor(enc.writer(), state, ut)
+	enc.sendTypeId(state, ut)
+	if enc.err != nil {
+		return enc.err
+	}
+
+	// Encode the object.
+	enc.encode(state.b, value, ut)
+	if enc.err == nil {
+		enc.writeMessage(enc.writer(), state.b)
+	}
+
+	enc.freeEncoderState(state)
+	return enc.err
+}
diff --git a/libgo/go/encoding/gob/encoder_test.go b/libgo/go/encoding/gob/encoder_test.go
new file mode 100644
index 00000000000..bc5af120af3
--- /dev/null
+++ b/libgo/go/encoding/gob/encoder_test.go
@@ -0,0 +1,664 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package gob
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"reflect"
+	"strings"
+	"testing"
+)
+
+type ET2 struct {
+	X string
+}
+
+type ET1 struct {
+	A    int
+	Et2  *ET2
+	Next *ET1
+}
+
+// Like ET1 but with a different name for a field
+type ET3 struct {
+	A             int
+	Et2           *ET2
+	DifferentNext *ET1
+}
+
+// Like ET1 but with a different type for a field
+type ET4 struct {
+	A    int
+	Et2  float64
+	Next int
+}
+
+func TestEncoderDecoder(t *testing.T) {
+	b := new(bytes.Buffer)
+	enc := NewEncoder(b)
+	et1 := new(ET1)
+	et1.A = 7
+	et1.Et2 = new(ET2)
+	err := enc.Encode(et1)
+	if err != nil {
+		t.Error("encoder fail:", err)
+	}
+	dec := NewDecoder(b)
+	newEt1 := new(ET1)
+	err = dec.Decode(newEt1)
+	if err != nil {
+		t.Fatal("error decoding ET1:", err)
+	}
+
+	if !reflect.DeepEqual(et1, newEt1) {
+		t.Fatalf("invalid data for et1: expected %+v; got %+v", *et1, *newEt1)
+	}
+	if b.Len() != 0 {
+		t.Error("not at eof;", b.Len(), "bytes left")
+	}
+
+	enc.Encode(et1)
+	newEt1 = new(ET1)
+	err = dec.Decode(newEt1)
+	if err != nil {
+		t.Fatal("round 2: error decoding ET1:", err)
+	}
+	if !reflect.DeepEqual(et1, newEt1) {
+		t.Fatalf("round 2: invalid data for et1: expected %+v; got %+v", *et1, *newEt1)
+	}
+	if b.Len() != 0 {
+		t.Error("round 2: not at eof;", b.Len(), "bytes left")
+	}
+
+	// Now test with a running encoder/decoder pair that we recognize a type mismatch.
+	err = enc.Encode(et1)
+	if err != nil {
+		t.Error("round 3: encoder fail:", err)
+	}
+	newEt2 := new(ET2)
+	err = dec.Decode(newEt2)
+	if err == nil {
+		t.Fatal("round 3: expected `bad type' error decoding ET2")
+	}
+}
+
+// Run one value through the encoder/decoder, but use the wrong type.
+// Input is always an ET1; we compare it to whatever is under 'e'.
+func badTypeCheck(e interface{}, shouldFail bool, msg string, t *testing.T) {
+	b := new(bytes.Buffer)
+	enc := NewEncoder(b)
+	et1 := new(ET1)
+	et1.A = 7
+	et1.Et2 = new(ET2)
+	err := enc.Encode(et1)
+	if err != nil {
+		t.Error("encoder fail:", err)
+	}
+	dec := NewDecoder(b)
+	err = dec.Decode(e)
+	if shouldFail && err == nil {
+		t.Error("expected error for", msg)
+	}
+	if !shouldFail && err != nil {
+		t.Error("unexpected error for", msg, err)
+	}
+}
+
+// Test that we recognize a bad type the first time.
+func TestWrongTypeDecoder(t *testing.T) {
+	badTypeCheck(new(ET2), true, "no fields in common", t)
+	badTypeCheck(new(ET3), false, "different name of field", t)
+	badTypeCheck(new(ET4), true, "different type of field", t)
+}
+
+func corruptDataCheck(s string, err error, t *testing.T) {
+	b := bytes.NewBufferString(s)
+	dec := NewDecoder(b)
+	err1 := dec.Decode(new(ET2))
+	if err1 != err {
+		t.Errorf("from %q expected error %s; got %s", s, err, err1)
+	}
+}
+
+// Check that we survive bad data.
+func TestBadData(t *testing.T) {
+	corruptDataCheck("", io.EOF, t)
+	corruptDataCheck("\x7Fhi", io.ErrUnexpectedEOF, t)
+	corruptDataCheck("\x03now is the time for all good men", errBadType, t)
+}
+
+// Types not supported by the Encoder.
+var unsupportedValues = []interface{}{
+	make(chan int),
+	func(a int) bool { return true },
+}
+
+func TestUnsupported(t *testing.T) {
+	var b bytes.Buffer
+	enc := NewEncoder(&b)
+	for _, v := range unsupportedValues {
+		err := enc.Encode(v)
+		if err == nil {
+			t.Errorf("expected error for %T; got none", v)
+		}
+	}
+}
+
+func encAndDec(in, out interface{}) error {
+	b := new(bytes.Buffer)
+	enc := NewEncoder(b)
+	err := enc.Encode(in)
+	if err != nil {
+		return err
+	}
+	dec := NewDecoder(b)
+	err = dec.Decode(out)
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+func TestTypeToPtrType(t *testing.T) {
+	// Encode a T, decode a *T
+	type Type0 struct {
+		A int
+	}
+	t0 := Type0{7}
+	t0p := new(Type0)
+	if err := encAndDec(t0, t0p); err != nil {
+		t.Error(err)
+	}
+}
+
+func TestPtrTypeToType(t *testing.T) {
+	// Encode a *T, decode a T
+	type Type1 struct {
+		A uint
+	}
+	t1p := &Type1{17}
+	var t1 Type1
+	if err := encAndDec(t1, t1p); err != nil {
+		t.Error(err)
+	}
+}
+
+func TestTypeToPtrPtrPtrPtrType(t *testing.T) {
+	type Type2 struct {
+		A ****float64
+	}
+	t2 := Type2{}
+	t2.A = new(***float64)
+	*t2.A = new(**float64)
+	**t2.A = new(*float64)
+	***t2.A = new(float64)
+	****t2.A = 27.4
+	t2pppp := new(***Type2)
+	if err := encAndDec(t2, t2pppp); err != nil {
+		t.Fatal(err)
+	}
+	if ****(****t2pppp).A != ****t2.A {
+		t.Errorf("wrong value after decode: %g not %g", ****(****t2pppp).A, ****t2.A)
+	}
+}
+
+func TestSlice(t *testing.T) {
+	type Type3 struct {
+		A []string
+	}
+	t3p := &Type3{[]string{"hello", "world"}}
+	var t3 Type3
+	if err := encAndDec(t3, t3p); err != nil {
+		t.Error(err)
+	}
+}
+
+func TestValueError(t *testing.T) {
+	// Encode a *T, decode a T
+	type Type4 struct {
+		A int
+	}
+	t4p := &Type4{3}
+	var t4 Type4 // note: not a pointer.
+	if err := encAndDec(t4p, t4); err == nil || strings.Index(err.Error(), "pointer") < 0 {
+		t.Error("expected error about pointer; got", err)
+	}
+}
+
+func TestArray(t *testing.T) {
+	type Type5 struct {
+		A [3]string
+		B [3]byte
+	}
+	type Type6 struct {
+		A [2]string // can't hold t5.a
+	}
+	t5 := Type5{[3]string{"hello", ",", "world"}, [3]byte{1, 2, 3}}
+	var t5p Type5
+	if err := encAndDec(t5, &t5p); err != nil {
+		t.Error(err)
+	}
+	var t6 Type6
+	if err := encAndDec(t5, &t6); err == nil {
+		t.Error("should fail with mismatched array sizes")
+	}
+}
+
+func TestRecursiveMapType(t *testing.T) {
+	type recursiveMap map[string]recursiveMap
+	r1 := recursiveMap{"A": recursiveMap{"B": nil, "C": nil}, "D": nil}
+	r2 := make(recursiveMap)
+	if err := encAndDec(r1, &r2); err != nil {
+		t.Error(err)
+	}
+}
+
+func TestRecursiveSliceType(t *testing.T) {
+	type recursiveSlice []recursiveSlice
+	r1 := recursiveSlice{0: recursiveSlice{0: nil}, 1: nil}
+	r2 := make(recursiveSlice, 0)
+	if err := encAndDec(r1, &r2); err != nil {
+		t.Error(err)
+	}
+}
+
+// Regression test for bug: must send zero values inside arrays
+func TestDefaultsInArray(t *testing.T) {
+	type Type7 struct {
+		B []bool
+		I []int
+		S []string
+		F []float64
+	}
+	t7 := Type7{
+		[]bool{false, false, true},
+		[]int{0, 0, 1},
+		[]string{"hi", "", "there"},
+		[]float64{0, 0, 1},
+	}
+	var t7p Type7
+	if err := encAndDec(t7, &t7p); err != nil {
+		t.Error(err)
+	}
+}
+
+var testInt int
+var testFloat32 float32
+var testString string
+var testSlice []string
+var testMap map[string]int
+var testArray [7]int
+
+type SingleTest struct {
+	in  interface{}
+	out interface{}
+	err string
+}
+
+var singleTests = []SingleTest{
+	{17, &testInt, ""},
+	{float32(17.5), &testFloat32, ""},
+	{"bike shed", &testString, ""},
+	{[]string{"bike", "shed", "paint", "color"}, &testSlice, ""},
+	{map[string]int{"seven": 7, "twelve": 12}, &testMap, ""},
+	{[7]int{4, 55, 0, 0, 0, 0, 0}, &testArray, ""}, // case that once triggered a bug
+	{[7]int{4, 55, 1, 44, 22, 66, 1234}, &testArray, ""},
+
+	// Decode errors
+	{172, &testFloat32, "wrong type"},
+}
+
+func TestSingletons(t *testing.T) {
+	b := new(bytes.Buffer)
+	enc := NewEncoder(b)
+	dec := NewDecoder(b)
+	for _, test := range singleTests {
+		b.Reset()
+		err := enc.Encode(test.in)
+		if err != nil {
+			t.Errorf("error encoding %v: %s", test.in, err)
+			continue
+		}
+		err = dec.Decode(test.out)
+		switch {
+		case err != nil && test.err == "":
+			t.Errorf("error decoding %v: %s", test.in, err)
+			continue
+		case err == nil && test.err != "":
+			t.Errorf("expected error decoding %v: %s", test.in, test.err)
+			continue
+		case err != nil && test.err != "":
+			if strings.Index(err.Error(), test.err) < 0 {
+				t.Errorf("wrong error decoding %v: wanted %s, got %v", test.in, test.err, err)
+			}
+			continue
+		}
+		// Get rid of the pointer in the rhs
+		val := reflect.ValueOf(test.out).Elem().Interface()
+		if !reflect.DeepEqual(test.in, val) {
+			t.Errorf("decoding singleton: expected %v got %v", test.in, val)
+		}
+	}
+}
+
+func TestStructNonStruct(t *testing.T) {
+	type Struct struct {
+		A string
+	}
+	type NonStruct string
+	s := Struct{"hello"}
+	var sp Struct
+	if err := encAndDec(s, &sp); err != nil {
+		t.Error(err)
+	}
+	var ns NonStruct
+	if err := encAndDec(s, &ns); err == nil {
+		t.Error("should get error for struct/non-struct")
+	} else if strings.Index(err.Error(), "type") < 0 {
+		t.Error("for struct/non-struct expected type error; got", err)
+	}
+	// Now try the other way
+	var nsp NonStruct
+	if err := encAndDec(ns, &nsp); err != nil {
+		t.Error(err)
+	}
+	if err := encAndDec(ns, &s); err == nil {
+		t.Error("should get error for non-struct/struct")
+	} else if strings.Index(err.Error(), "type") < 0 {
+		t.Error("for non-struct/struct expected type error; got", err)
+	}
+}
+
+type interfaceIndirectTestI interface {
+	F() bool
+}
+
+type interfaceIndirectTestT struct{}
+
+func (this *interfaceIndirectTestT) F() bool {
+	return true
+}
+
+// A version of a bug reported on golang-nuts.  Also tests top-level
+// slice of interfaces.  The issue was registering *T caused T to be
+// stored as the concrete type.
+func TestInterfaceIndirect(t *testing.T) {
+	Register(&interfaceIndirectTestT{})
+	b := new(bytes.Buffer)
+	w := []interfaceIndirectTestI{&interfaceIndirectTestT{}}
+	err := NewEncoder(b).Encode(w)
+	if err != nil {
+		t.Fatal("encode error:", err)
+	}
+
+	var r []interfaceIndirectTestI
+	err = NewDecoder(b).Decode(&r)
+	if err != nil {
+		t.Fatal("decode error:", err)
+	}
+}
+
+// Now follow various tests that decode into things that can't represent the
+// encoded value, all of which should be legal.
+
+// Also, when the ignored object contains an interface value, it may define
+// types. Make sure that skipping the value still defines the types by using
+// the encoder/decoder pair to send a value afterwards.  If an interface
+// is sent, its type in the test is always NewType0, so this checks that the
+// encoder and decoder don't skew with respect to type definitions.
+
+type Struct0 struct {
+	I interface{}
+}
+
+type NewType0 struct {
+	S string
+}
+
+type ignoreTest struct {
+	in, out interface{}
+}
+
+var ignoreTests = []ignoreTest{
+	// Decode normal struct into an empty struct
+	{&struct{ A int }{23}, &struct{}{}},
+	// Decode normal struct into a nil.
+	{&struct{ A int }{23}, nil},
+	// Decode singleton string into a nil.
+	{"hello, world", nil},
+	// Decode singleton slice into a nil.
+	{[]int{1, 2, 3, 4}, nil},
+	// Decode struct containing an interface into a nil.
+	{&Struct0{&NewType0{"value0"}}, nil},
+	// Decode singleton slice of interfaces into a nil.
+	{[]interface{}{"hi", &NewType0{"value1"}, 23}, nil},
+}
+
+func TestDecodeIntoNothing(t *testing.T) {
+	Register(new(NewType0))
+	for i, test := range ignoreTests {
+		b := new(bytes.Buffer)
+		enc := NewEncoder(b)
+		err := enc.Encode(test.in)
+		if err != nil {
+			t.Errorf("%d: encode error %s:", i, err)
+			continue
+		}
+		dec := NewDecoder(b)
+		err = dec.Decode(test.out)
+		if err != nil {
+			t.Errorf("%d: decode error: %s", i, err)
+			continue
+		}
+		// Now see if the encoder and decoder are in a consistent state.
+		str := fmt.Sprintf("Value %d", i)
+		err = enc.Encode(&NewType0{str})
+		if err != nil {
+			t.Fatalf("%d: NewType0 encode error: %s", i, err)
+		}
+		ns := new(NewType0)
+		err = dec.Decode(ns)
+		if err != nil {
+			t.Fatalf("%d: NewType0 decode error: %s", i, err)
+		}
+		if ns.S != str {
+			t.Fatalf("%d: expected %q got %q", i, str, ns.S)
+		}
+	}
+}
+
+// Another bug from golang-nuts, involving nested interfaces.
+type Bug0Outer struct {
+	Bug0Field interface{}
+}
+
+type Bug0Inner struct {
+	A int
+}
+
+func TestNestedInterfaces(t *testing.T) {
+	var buf bytes.Buffer
+	e := NewEncoder(&buf)
+	d := NewDecoder(&buf)
+	Register(new(Bug0Outer))
+	Register(new(Bug0Inner))
+	f := &Bug0Outer{&Bug0Outer{&Bug0Inner{7}}}
+	var v interface{} = f
+	err := e.Encode(&v)
+	if err != nil {
+		t.Fatal("Encode:", err)
+	}
+	err = d.Decode(&v)
+	if err != nil {
+		t.Fatal("Decode:", err)
+	}
+	// Make sure it decoded correctly.
+	outer1, ok := v.(*Bug0Outer)
+	if !ok {
+		t.Fatalf("v not Bug0Outer: %T", v)
+	}
+	outer2, ok := outer1.Bug0Field.(*Bug0Outer)
+	if !ok {
+		t.Fatalf("v.Bug0Field not Bug0Outer: %T", outer1.Bug0Field)
+	}
+	inner, ok := outer2.Bug0Field.(*Bug0Inner)
+	if !ok {
+		t.Fatalf("v.Bug0Field.Bug0Field not Bug0Inner: %T", outer2.Bug0Field)
+	}
+	if inner.A != 7 {
+		t.Fatalf("final value %d; expected %d", inner.A, 7)
+	}
+}
+
+// The bugs keep coming. We forgot to send map subtypes before the map.
+
+type Bug1Elem struct {
+	Name string
+	Id   int
+}
+
+type Bug1StructMap map[string]Bug1Elem
+
+func bug1EncDec(in Bug1StructMap, out *Bug1StructMap) error {
+	return nil
+}
+
+func TestMapBug1(t *testing.T) {
+	in := make(Bug1StructMap)
+	in["val1"] = Bug1Elem{"elem1", 1}
+	in["val2"] = Bug1Elem{"elem2", 2}
+
+	b := new(bytes.Buffer)
+	enc := NewEncoder(b)
+	err := enc.Encode(in)
+	if err != nil {
+		t.Fatal("encode:", err)
+	}
+	dec := NewDecoder(b)
+	out := make(Bug1StructMap)
+	err = dec.Decode(&out)
+	if err != nil {
+		t.Fatal("decode:", err)
+	}
+	if !reflect.DeepEqual(in, out) {
+		t.Errorf("mismatch: %v %v", in, out)
+	}
+}
+
+func TestGobMapInterfaceEncode(t *testing.T) {
+	m := map[string]interface{}{
+		"up": uintptr(0),
+		"i0": []int{-1},
+		"i1": []int8{-1},
+		"i2": []int16{-1},
+		"i3": []int32{-1},
+		"i4": []int64{-1},
+		"u0": []uint{1},
+		"u1": []uint8{1},
+		"u2": []uint16{1},
+		"u3": []uint32{1},
+		"u4": []uint64{1},
+		"f0": []float32{1},
+		"f1": []float64{1},
+		"c0": []complex64{complex(2, -2)},
+		"c1": []complex128{complex(2, float64(-2))},
+		"us": []uintptr{0},
+		"bo": []bool{false},
+		"st": []string{"s"},
+	}
+	buf := bytes.NewBuffer(nil)
+	enc := NewEncoder(buf)
+	err := enc.Encode(m)
+	if err != nil {
+		t.Errorf("encode map: %s", err)
+	}
+}
+
+func TestSliceReusesMemory(t *testing.T) {
+	buf := bytes.NewBuffer(nil)
+	// Bytes
+	{
+		x := []byte("abcd")
+		enc := NewEncoder(buf)
+		err := enc.Encode(x)
+		if err != nil {
+			t.Errorf("bytes: encode: %s", err)
+		}
+		// Decode into y, which is big enough.
+		y := []byte("ABCDE")
+		addr := &y[0]
+		dec := NewDecoder(buf)
+		err = dec.Decode(&y)
+		if err != nil {
+			t.Fatal("bytes: decode:", err)
+		}
+		if !bytes.Equal(x, y) {
+			t.Errorf("bytes: expected %q got %q\n", x, y)
+		}
+		if addr != &y[0] {
+			t.Errorf("bytes: unnecessary reallocation")
+		}
+	}
+	// general slice
+	{
+		x := []rune("abcd")
+		enc := NewEncoder(buf)
+		err := enc.Encode(x)
+		if err != nil {
+			t.Errorf("ints: encode: %s", err)
+		}
+		// Decode into y, which is big enough.
+		y := []rune("ABCDE")
+		addr := &y[0]
+		dec := NewDecoder(buf)
+		err = dec.Decode(&y)
+		if err != nil {
+			t.Fatal("ints: decode:", err)
+		}
+		if !reflect.DeepEqual(x, y) {
+			t.Errorf("ints: expected %q got %q\n", x, y)
+		}
+		if addr != &y[0] {
+			t.Errorf("ints: unnecessary reallocation")
+		}
+	}
+}
+
+// Used to crash: negative count in recvMessage.
+func TestBadCount(t *testing.T) {
+	b := []byte{0xfb, 0xa5, 0x82, 0x2f, 0xca, 0x1}
+	if err := NewDecoder(bytes.NewBuffer(b)).Decode(nil); err == nil {
+		t.Error("expected error from bad count")
+	} else if err.Error() != errBadCount.Error() {
+		t.Error("expected bad count error; got", err)
+	}
+}
+
+// Verify that sequential Decoders built on a single input will
+// succeed if the input implements ReadByte and there is no
+// type information in the stream.
+func TestSequentialDecoder(t *testing.T) {
+	b := new(bytes.Buffer)
+	enc := NewEncoder(b)
+	const count = 10
+	for i := 0; i < count; i++ {
+		s := fmt.Sprintf("%d", i)
+		if err := enc.Encode(s); err != nil {
+			t.Error("encoder fail:", err)
+		}
+	}
+	for i := 0; i < count; i++ {
+		dec := NewDecoder(b)
+		var s string
+		if err := dec.Decode(&s); err != nil {
+			t.Fatal("decoder fail:", err)
+		}
+		if s != fmt.Sprintf("%d", i) {
+			t.Fatalf("decode expected %d got %s", i, s)
+		}
+	}
+}
diff --git a/libgo/go/encoding/gob/error.go b/libgo/go/encoding/gob/error.go
new file mode 100644
index 00000000000..fbae8b683da
--- /dev/null
+++ b/libgo/go/encoding/gob/error.go
@@ -0,0 +1,39 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package gob
+
+import "fmt"
+
+// Errors in decoding and encoding are handled using panic and recover.
+// Panics caused by user error (that is, everything except run-time panics
+// such as "index out of bounds" errors) do not leave the file that caused
+// them, but are instead turned into plain error returns.  Encoding and
+// decoding functions and methods that do not return an error either use
+// panic to report an error or are guaranteed error-free.
+
+// A gobError is used to distinguish errors (panics) generated in this package.
+type gobError struct {
+	err error
+}
+
+// errorf is like error_ but takes Printf-style arguments to construct an error.
+// It always prefixes the message with "gob: ".
+func errorf(format string, args ...interface{}) {
+	error_(fmt.Errorf("gob: "+format, args...))
+}
+
+// error wraps the argument error and uses it as the argument to panic.
+func error_(err error) {
+	panic(gobError{err})
+}
+
+// catchError is meant to be used as a deferred function to turn a panic(gobError) into a
+// plain error.  It overwrites the error return of the function that deferred its call.
+func catchError(err *error) {
+	if e := recover(); e != nil {
+		*err = e.(gobError).err // Will re-panic if not one of our errors, such as a runtime error.
+	}
+	return
+}
diff --git a/libgo/go/encoding/gob/gobencdec_test.go b/libgo/go/encoding/gob/gobencdec_test.go
new file mode 100644
index 00000000000..eacfd842db3
--- /dev/null
+++ b/libgo/go/encoding/gob/gobencdec_test.go
@@ -0,0 +1,528 @@
+// Copyright 20011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// This file contains tests of the GobEncoder/GobDecoder support.
+
+package gob
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"io"
+	"strings"
+	"testing"
+)
+
+// Types that implement the GobEncoder/Decoder interfaces.
+
+type ByteStruct struct {
+	a byte // not an exported field
+}
+
+type StringStruct struct {
+	s string // not an exported field
+}
+
+type ArrayStruct struct {
+	a [8192]byte // not an exported field
+}
+
+type Gobber int
+
+type ValueGobber string // encodes with a value, decodes with a pointer.
+
+// The relevant methods
+
+func (g *ByteStruct) GobEncode() ([]byte, error) {
+	b := make([]byte, 3)
+	b[0] = g.a
+	b[1] = g.a + 1
+	b[2] = g.a + 2
+	return b, nil
+}
+
+func (g *ByteStruct) GobDecode(data []byte) error {
+	if g == nil {
+		return errors.New("NIL RECEIVER")
+	}
+	// Expect N sequential-valued bytes.
+	if len(data) == 0 {
+		return io.EOF
+	}
+	g.a = data[0]
+	for i, c := range data {
+		if c != g.a+byte(i) {
+			return errors.New("invalid data sequence")
+		}
+	}
+	return nil
+}
+
+func (g *StringStruct) GobEncode() ([]byte, error) {
+	return []byte(g.s), nil
+}
+
+func (g *StringStruct) GobDecode(data []byte) error {
+	// Expect N sequential-valued bytes.
+	if len(data) == 0 {
+		return io.EOF
+	}
+	a := data[0]
+	for i, c := range data {
+		if c != a+byte(i) {
+			return errors.New("invalid data sequence")
+		}
+	}
+	g.s = string(data)
+	return nil
+}
+
+func (a *ArrayStruct) GobEncode() ([]byte, error) {
+	return a.a[:], nil
+}
+
+func (a *ArrayStruct) GobDecode(data []byte) error {
+	if len(data) != len(a.a) {
+		return errors.New("wrong length in array decode")
+	}
+	copy(a.a[:], data)
+	return nil
+}
+
+func (g *Gobber) GobEncode() ([]byte, error) {
+	return []byte(fmt.Sprintf("VALUE=%d", *g)), nil
+}
+
+func (g *Gobber) GobDecode(data []byte) error {
+	_, err := fmt.Sscanf(string(data), "VALUE=%d", (*int)(g))
+	return err
+}
+
+func (v ValueGobber) GobEncode() ([]byte, error) {
+	return []byte(fmt.Sprintf("VALUE=%s", v)), nil
+}
+
+func (v *ValueGobber) GobDecode(data []byte) error {
+	_, err := fmt.Sscanf(string(data), "VALUE=%s", (*string)(v))
+	return err
+}
+
+// Structs that include GobEncodable fields.
+
+type GobTest0 struct {
+	X int // guarantee we have  something in common with GobTest*
+	G *ByteStruct
+}
+
+type GobTest1 struct {
+	X int // guarantee we have  something in common with GobTest*
+	G *StringStruct
+}
+
+type GobTest2 struct {
+	X int    // guarantee we have  something in common with GobTest*
+	G string // not a GobEncoder - should give us errors
+}
+
+type GobTest3 struct {
+	X int // guarantee we have  something in common with GobTest*
+	G *Gobber
+}
+
+type GobTest4 struct {
+	X int // guarantee we have  something in common with GobTest*
+	V ValueGobber
+}
+
+type GobTest5 struct {
+	X int // guarantee we have  something in common with GobTest*
+	V *ValueGobber
+}
+
+type GobTestIgnoreEncoder struct {
+	X int // guarantee we have  something in common with GobTest*
+}
+
+type GobTestValueEncDec struct {
+	X int          // guarantee we have  something in common with GobTest*
+	G StringStruct // not a pointer.
+}
+
+type GobTestIndirectEncDec struct {
+	X int             // guarantee we have  something in common with GobTest*
+	G ***StringStruct // indirections to the receiver.
+}
+
+type GobTestArrayEncDec struct {
+	X int         // guarantee we have  something in common with GobTest*
+	A ArrayStruct // not a pointer.
+}
+
+type GobTestIndirectArrayEncDec struct {
+	X int            // guarantee we have  something in common with GobTest*
+	A ***ArrayStruct // indirections to a large receiver.
+}
+
+func TestGobEncoderField(t *testing.T) {
+	b := new(bytes.Buffer)
+	// First a field that's a structure.
+	enc := NewEncoder(b)
+	err := enc.Encode(GobTest0{17, &ByteStruct{'A'}})
+	if err != nil {
+		t.Fatal("encode error:", err)
+	}
+	dec := NewDecoder(b)
+	x := new(GobTest0)
+	err = dec.Decode(x)
+	if err != nil {
+		t.Fatal("decode error:", err)
+	}
+	if x.G.a != 'A' {
+		t.Errorf("expected 'A' got %c", x.G.a)
+	}
+	// Now a field that's not a structure.
+	b.Reset()
+	gobber := Gobber(23)
+	err = enc.Encode(GobTest3{17, &gobber})
+	if err != nil {
+		t.Fatal("encode error:", err)
+	}
+	y := new(GobTest3)
+	err = dec.Decode(y)
+	if err != nil {
+		t.Fatal("decode error:", err)
+	}
+	if *y.G != 23 {
+		t.Errorf("expected '23 got %d", *y.G)
+	}
+}
+
+// Even though the field is a value, we can still take its address
+// and should be able to call the methods.
+func TestGobEncoderValueField(t *testing.T) {
+	b := new(bytes.Buffer)
+	// First a field that's a structure.
+	enc := NewEncoder(b)
+	err := enc.Encode(GobTestValueEncDec{17, StringStruct{"HIJKL"}})
+	if err != nil {
+		t.Fatal("encode error:", err)
+	}
+	dec := NewDecoder(b)
+	x := new(GobTestValueEncDec)
+	err = dec.Decode(x)
+	if err != nil {
+		t.Fatal("decode error:", err)
+	}
+	if x.G.s != "HIJKL" {
+		t.Errorf("expected `HIJKL` got %s", x.G.s)
+	}
+}
+
+// GobEncode/Decode should work even if the value is
+// more indirect than the receiver.
+func TestGobEncoderIndirectField(t *testing.T) {
+	b := new(bytes.Buffer)
+	// First a field that's a structure.
+	enc := NewEncoder(b)
+	s := &StringStruct{"HIJKL"}
+	sp := &s
+	err := enc.Encode(GobTestIndirectEncDec{17, &sp})
+	if err != nil {
+		t.Fatal("encode error:", err)
+	}
+	dec := NewDecoder(b)
+	x := new(GobTestIndirectEncDec)
+	err = dec.Decode(x)
+	if err != nil {
+		t.Fatal("decode error:", err)
+	}
+	if (***x.G).s != "HIJKL" {
+		t.Errorf("expected `HIJKL` got %s", (***x.G).s)
+	}
+}
+
+// Test with a large field with methods.
+func TestGobEncoderArrayField(t *testing.T) {
+	b := new(bytes.Buffer)
+	enc := NewEncoder(b)
+	var a GobTestArrayEncDec
+	a.X = 17
+	for i := range a.A.a {
+		a.A.a[i] = byte(i)
+	}
+	err := enc.Encode(a)
+	if err != nil {
+		t.Fatal("encode error:", err)
+	}
+	dec := NewDecoder(b)
+	x := new(GobTestArrayEncDec)
+	err = dec.Decode(x)
+	if err != nil {
+		t.Fatal("decode error:", err)
+	}
+	for i, v := range x.A.a {
+		if v != byte(i) {
+			t.Errorf("expected %x got %x", byte(i), v)
+			break
+		}
+	}
+}
+
+// Test an indirection to a large field with methods.
+func TestGobEncoderIndirectArrayField(t *testing.T) {
+	b := new(bytes.Buffer)
+	enc := NewEncoder(b)
+	var a GobTestIndirectArrayEncDec
+	a.X = 17
+	var array ArrayStruct
+	ap := &array
+	app := &ap
+	a.A = &app
+	for i := range array.a {
+		array.a[i] = byte(i)
+	}
+	err := enc.Encode(a)
+	if err != nil {
+		t.Fatal("encode error:", err)
+	}
+	dec := NewDecoder(b)
+	x := new(GobTestIndirectArrayEncDec)
+	err = dec.Decode(x)
+	if err != nil {
+		t.Fatal("decode error:", err)
+	}
+	for i, v := range (***x.A).a {
+		if v != byte(i) {
+			t.Errorf("expected %x got %x", byte(i), v)
+			break
+		}
+	}
+}
+
+// As long as the fields have the same name and implement the
+// interface, we can cross-connect them.  Not sure it's useful
+// and may even be bad but it works and it's hard to prevent
+// without exposing the contents of the object, which would
+// defeat the purpose.
+func TestGobEncoderFieldsOfDifferentType(t *testing.T) {
+	// first, string in field to byte in field
+	b := new(bytes.Buffer)
+	enc := NewEncoder(b)
+	err := enc.Encode(GobTest1{17, &StringStruct{"ABC"}})
+	if err != nil {
+		t.Fatal("encode error:", err)
+	}
+	dec := NewDecoder(b)
+	x := new(GobTest0)
+	err = dec.Decode(x)
+	if err != nil {
+		t.Fatal("decode error:", err)
+	}
+	if x.G.a != 'A' {
+		t.Errorf("expected 'A' got %c", x.G.a)
+	}
+	// now the other direction, byte in field to string in field
+	b.Reset()
+	err = enc.Encode(GobTest0{17, &ByteStruct{'X'}})
+	if err != nil {
+		t.Fatal("encode error:", err)
+	}
+	y := new(GobTest1)
+	err = dec.Decode(y)
+	if err != nil {
+		t.Fatal("decode error:", err)
+	}
+	if y.G.s != "XYZ" {
+		t.Fatalf("expected `XYZ` got %c", y.G.s)
+	}
+}
+
+// Test that we can encode a value and decode into a pointer.
+func TestGobEncoderValueEncoder(t *testing.T) {
+	// first, string in field to byte in field
+	b := new(bytes.Buffer)
+	enc := NewEncoder(b)
+	err := enc.Encode(GobTest4{17, ValueGobber("hello")})
+	if err != nil {
+		t.Fatal("encode error:", err)
+	}
+	dec := NewDecoder(b)
+	x := new(GobTest5)
+	err = dec.Decode(x)
+	if err != nil {
+		t.Fatal("decode error:", err)
+	}
+	if *x.V != "hello" {
+		t.Errorf("expected `hello` got %s", x.V)
+	}
+}
+
+func TestGobEncoderFieldTypeError(t *testing.T) {
+	// GobEncoder to non-decoder: error
+	b := new(bytes.Buffer)
+	enc := NewEncoder(b)
+	err := enc.Encode(GobTest1{17, &StringStruct{"ABC"}})
+	if err != nil {
+		t.Fatal("encode error:", err)
+	}
+	dec := NewDecoder(b)
+	x := &GobTest2{}
+	err = dec.Decode(x)
+	if err == nil {
+		t.Fatal("expected decode error for mismatched fields (encoder to non-decoder)")
+	}
+	if strings.Index(err.Error(), "type") < 0 {
+		t.Fatal("expected type error; got", err)
+	}
+	// Non-encoder to GobDecoder: error
+	b.Reset()
+	err = enc.Encode(GobTest2{17, "ABC"})
+	if err != nil {
+		t.Fatal("encode error:", err)
+	}
+	y := &GobTest1{}
+	err = dec.Decode(y)
+	if err == nil {
+		t.Fatal("expected decode error for mismatched fields (non-encoder to decoder)")
+	}
+	if strings.Index(err.Error(), "type") < 0 {
+		t.Fatal("expected type error; got", err)
+	}
+}
+
+// Even though ByteStruct is a struct, it's treated as a singleton at the top level.
+func TestGobEncoderStructSingleton(t *testing.T) {
+	b := new(bytes.Buffer)
+	enc := NewEncoder(b)
+	err := enc.Encode(&ByteStruct{'A'})
+	if err != nil {
+		t.Fatal("encode error:", err)
+	}
+	dec := NewDecoder(b)
+	x := new(ByteStruct)
+	err = dec.Decode(x)
+	if err != nil {
+		t.Fatal("decode error:", err)
+	}
+	if x.a != 'A' {
+		t.Errorf("expected 'A' got %c", x.a)
+	}
+}
+
+func TestGobEncoderNonStructSingleton(t *testing.T) {
+	b := new(bytes.Buffer)
+	enc := NewEncoder(b)
+	err := enc.Encode(Gobber(1234))
+	if err != nil {
+		t.Fatal("encode error:", err)
+	}
+	dec := NewDecoder(b)
+	var x Gobber
+	err = dec.Decode(&x)
+	if err != nil {
+		t.Fatal("decode error:", err)
+	}
+	if x != 1234 {
+		t.Errorf("expected 1234 got %d", x)
+	}
+}
+
+func TestGobEncoderIgnoreStructField(t *testing.T) {
+	b := new(bytes.Buffer)
+	// First a field that's a structure.
+	enc := NewEncoder(b)
+	err := enc.Encode(GobTest0{17, &ByteStruct{'A'}})
+	if err != nil {
+		t.Fatal("encode error:", err)
+	}
+	dec := NewDecoder(b)
+	x := new(GobTestIgnoreEncoder)
+	err = dec.Decode(x)
+	if err != nil {
+		t.Fatal("decode error:", err)
+	}
+	if x.X != 17 {
+		t.Errorf("expected 17 got %c", x.X)
+	}
+}
+
+func TestGobEncoderIgnoreNonStructField(t *testing.T) {
+	b := new(bytes.Buffer)
+	// First a field that's a structure.
+	enc := NewEncoder(b)
+	gobber := Gobber(23)
+	err := enc.Encode(GobTest3{17, &gobber})
+	if err != nil {
+		t.Fatal("encode error:", err)
+	}
+	dec := NewDecoder(b)
+	x := new(GobTestIgnoreEncoder)
+	err = dec.Decode(x)
+	if err != nil {
+		t.Fatal("decode error:", err)
+	}
+	if x.X != 17 {
+		t.Errorf("expected 17 got %c", x.X)
+	}
+}
+
+func TestGobEncoderIgnoreNilEncoder(t *testing.T) {
+	b := new(bytes.Buffer)
+	// First a field that's a structure.
+	enc := NewEncoder(b)
+	err := enc.Encode(GobTest0{X: 18}) // G is nil
+	if err != nil {
+		t.Fatal("encode error:", err)
+	}
+	dec := NewDecoder(b)
+	x := new(GobTest0)
+	err = dec.Decode(x)
+	if err != nil {
+		t.Fatal("decode error:", err)
+	}
+	if x.X != 18 {
+		t.Errorf("expected x.X = 18, got %v", x.X)
+	}
+	if x.G != nil {
+		t.Errorf("expected x.G = nil, got %v", x.G)
+	}
+}
+
+type gobDecoderBug0 struct {
+	foo, bar string
+}
+
+func (br *gobDecoderBug0) String() string {
+	return br.foo + "-" + br.bar
+}
+
+func (br *gobDecoderBug0) GobEncode() ([]byte, error) {
+	return []byte(br.String()), nil
+}
+
+func (br *gobDecoderBug0) GobDecode(b []byte) error {
+	br.foo = "foo"
+	br.bar = "bar"
+	return nil
+}
+
+// This was a bug: the receiver has a different indirection level
+// than the variable.
+func TestGobEncoderExtraIndirect(t *testing.T) {
+	gdb := &gobDecoderBug0{"foo", "bar"}
+	buf := new(bytes.Buffer)
+	e := NewEncoder(buf)
+	if err := e.Encode(gdb); err != nil {
+		t.Fatalf("encode: %v", err)
+	}
+	d := NewDecoder(buf)
+	var got *gobDecoderBug0
+	if err := d.Decode(&got); err != nil {
+		t.Fatalf("decode: %v", err)
+	}
+	if got.foo != gdb.foo || got.bar != gdb.bar {
+		t.Errorf("got = %q, want %q", got, gdb)
+	}
+}
diff --git a/libgo/go/encoding/gob/timing_test.go b/libgo/go/encoding/gob/timing_test.go
new file mode 100644
index 00000000000..47437a607f1
--- /dev/null
+++ b/libgo/go/encoding/gob/timing_test.go
@@ -0,0 +1,94 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package gob
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"os"
+	"runtime"
+	"testing"
+)
+
+type Bench struct {
+	A int
+	B float64
+	C string
+	D []byte
+}
+
+func benchmarkEndToEnd(r io.Reader, w io.Writer, b *testing.B) {
+	b.StopTimer()
+	enc := NewEncoder(w)
+	dec := NewDecoder(r)
+	bench := &Bench{7, 3.2, "now is the time", []byte("for all good men")}
+	b.StartTimer()
+	for i := 0; i < b.N; i++ {
+		if enc.Encode(bench) != nil {
+			panic("encode error")
+		}
+		if dec.Decode(bench) != nil {
+			panic("decode error")
+		}
+	}
+}
+
+func BenchmarkEndToEndPipe(b *testing.B) {
+	r, w, err := os.Pipe()
+	if err != nil {
+		panic("can't get pipe:" + err.Error())
+	}
+	benchmarkEndToEnd(r, w, b)
+}
+
+func BenchmarkEndToEndByteBuffer(b *testing.B) {
+	var buf bytes.Buffer
+	benchmarkEndToEnd(&buf, &buf, b)
+}
+
+func TestCountEncodeMallocs(t *testing.T) {
+	var buf bytes.Buffer
+	enc := NewEncoder(&buf)
+	bench := &Bench{7, 3.2, "now is the time", []byte("for all good men")}
+	runtime.UpdateMemStats()
+	mallocs := 0 - runtime.MemStats.Mallocs
+	const count = 1000
+	for i := 0; i < count; i++ {
+		err := enc.Encode(bench)
+		if err != nil {
+			t.Fatal("encode:", err)
+		}
+	}
+	runtime.UpdateMemStats()
+	mallocs += runtime.MemStats.Mallocs
+	fmt.Printf("mallocs per encode of type Bench: %d\n", mallocs/count)
+}
+
+func TestCountDecodeMallocs(t *testing.T) {
+	var buf bytes.Buffer
+	enc := NewEncoder(&buf)
+	bench := &Bench{7, 3.2, "now is the time", []byte("for all good men")}
+	const count = 1000
+	for i := 0; i < count; i++ {
+		err := enc.Encode(bench)
+		if err != nil {
+			t.Fatal("encode:", err)
+		}
+	}
+	dec := NewDecoder(&buf)
+	runtime.UpdateMemStats()
+	mallocs := 0 - runtime.MemStats.Mallocs
+	for i := 0; i < count; i++ {
+		*bench = Bench{}
+		err := dec.Decode(&bench)
+		if err != nil {
+			t.Fatal("decode:", err)
+		}
+	}
+	runtime.UpdateMemStats()
+	mallocs += runtime.MemStats.Mallocs
+	fmt.Printf("mallocs per decode of type Bench: %d\n", mallocs/count)
+}
diff --git a/libgo/go/encoding/gob/type.go b/libgo/go/encoding/gob/type.go
new file mode 100644
index 00000000000..1b20843fa25
--- /dev/null
+++ b/libgo/go/encoding/gob/type.go
@@ -0,0 +1,788 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package gob
+
+import (
+	"errors"
+	"fmt"
+	"os"
+	"reflect"
+	"sync"
+	"unicode"
+	"unicode/utf8"
+)
+
+// userTypeInfo stores the information associated with a type the user has handed
+// to the package.  It's computed once and stored in a map keyed by reflection
+// type.
+type userTypeInfo struct {
+	user         reflect.Type // the type the user handed us
+	base         reflect.Type // the base type after all indirections
+	indir        int          // number of indirections to reach the base type
+	isGobEncoder bool         // does the type implement GobEncoder?
+	isGobDecoder bool         // does the type implement GobDecoder?
+	encIndir     int8         // number of indirections to reach the receiver type; may be negative
+	decIndir     int8         // number of indirections to reach the receiver type; may be negative
+}
+
+var (
+	// Protected by an RWMutex because we read it a lot and write
+	// it only when we see a new type, typically when compiling.
+	userTypeLock  sync.RWMutex
+	userTypeCache = make(map[reflect.Type]*userTypeInfo)
+)
+
+// validType returns, and saves, the information associated with user-provided type rt.
+// If the user type is not valid, err will be non-nil.  To be used when the error handler
+// is not set up.
+func validUserType(rt reflect.Type) (ut *userTypeInfo, err error) {
+	userTypeLock.RLock()
+	ut = userTypeCache[rt]
+	userTypeLock.RUnlock()
+	if ut != nil {
+		return
+	}
+	// Now set the value under the write lock.
+	userTypeLock.Lock()
+	defer userTypeLock.Unlock()
+	if ut = userTypeCache[rt]; ut != nil {
+		// Lost the race; not a problem.
+		return
+	}
+	ut = new(userTypeInfo)
+	ut.base = rt
+	ut.user = rt
+	// A type that is just a cycle of pointers (such as type T *T) cannot
+	// be represented in gobs, which need some concrete data.  We use a
+	// cycle detection algorithm from Knuth, Vol 2, Section 3.1, Ex 6,
+	// pp 539-540.  As we step through indirections, run another type at
+	// half speed. If they meet up, there's a cycle.
+	slowpoke := ut.base // walks half as fast as ut.base
+	for {
+		pt := ut.base
+		if pt.Kind() != reflect.Ptr {
+			break
+		}
+		ut.base = pt.Elem()
+		if ut.base == slowpoke { // ut.base lapped slowpoke
+			// recursive pointer type.
+			return nil, errors.New("can't represent recursive pointer type " + ut.base.String())
+		}
+		if ut.indir%2 == 0 {
+			slowpoke = slowpoke.Elem()
+		}
+		ut.indir++
+	}
+	ut.isGobEncoder, ut.encIndir = implementsInterface(ut.user, gobEncoderInterfaceType)
+	ut.isGobDecoder, ut.decIndir = implementsInterface(ut.user, gobDecoderInterfaceType)
+	userTypeCache[rt] = ut
+	return
+}
+
+var (
+	gobEncoderInterfaceType = reflect.TypeOf((*GobEncoder)(nil)).Elem()
+	gobDecoderInterfaceType = reflect.TypeOf((*GobDecoder)(nil)).Elem()
+)
+
+// implementsInterface reports whether the type implements the
+// gobEncoder/gobDecoder interface.
+// It also returns the number of indirections required to get to the
+// implementation.
+func implementsInterface(typ, gobEncDecType reflect.Type) (success bool, indir int8) {
+	if typ == nil {
+		return
+	}
+	rt := typ
+	// The type might be a pointer and we need to keep
+	// dereferencing to the base type until we find an implementation.
+	for {
+		if rt.Implements(gobEncDecType) {
+			return true, indir
+		}
+		if p := rt; p.Kind() == reflect.Ptr {
+			indir++
+			if indir > 100 { // insane number of indirections
+				return false, 0
+			}
+			rt = p.Elem()
+			continue
+		}
+		break
+	}
+	// No luck yet, but if this is a base type (non-pointer), the pointer might satisfy.
+	if typ.Kind() != reflect.Ptr {
+		// Not a pointer, but does the pointer work?
+		if reflect.PtrTo(typ).Implements(gobEncDecType) {
+			return true, -1
+		}
+	}
+	return false, 0
+}
+
+// userType returns, and saves, the information associated with user-provided type rt.
+// If the user type is not valid, it calls error.
+func userType(rt reflect.Type) *userTypeInfo {
+	ut, err := validUserType(rt)
+	if err != nil {
+		error_(err)
+	}
+	return ut
+}
+// A typeId represents a gob Type as an integer that can be passed on the wire.
+// Internally, typeIds are used as keys to a map to recover the underlying type info.
+type typeId int32
+
+var nextId typeId       // incremented for each new type we build
+var typeLock sync.Mutex // set while building a type
+const firstUserId = 64  // lowest id number granted to user
+
+type gobType interface {
+	id() typeId
+	setId(id typeId)
+	name() string
+	string() string // not public; only for debugging
+	safeString(seen map[typeId]bool) string
+}
+
+var types = make(map[reflect.Type]gobType)
+var idToType = make(map[typeId]gobType)
+var builtinIdToType map[typeId]gobType // set in init() after builtins are established
+
+func setTypeId(typ gobType) {
+	nextId++
+	typ.setId(nextId)
+	idToType[nextId] = typ
+}
+
+func (t typeId) gobType() gobType {
+	if t == 0 {
+		return nil
+	}
+	return idToType[t]
+}
+
+// string returns the string representation of the type associated with the typeId.
+func (t typeId) string() string {
+	if t.gobType() == nil {
+		return "<nil>"
+	}
+	return t.gobType().string()
+}
+
+// Name returns the name of the type associated with the typeId.
+func (t typeId) name() string {
+	if t.gobType() == nil {
+		return "<nil>"
+	}
+	return t.gobType().name()
+}
+
+// Common elements of all types.
+type CommonType struct {
+	Name string
+	Id   typeId
+}
+
+func (t *CommonType) id() typeId { return t.Id }
+
+func (t *CommonType) setId(id typeId) { t.Id = id }
+
+func (t *CommonType) string() string { return t.Name }
+
+func (t *CommonType) safeString(seen map[typeId]bool) string {
+	return t.Name
+}
+
+func (t *CommonType) name() string { return t.Name }
+
+// Create and check predefined types
+// The string for tBytes is "bytes" not "[]byte" to signify its specialness.
+
+var (
+	// Primordial types, needed during initialization.
+	// Always passed as pointers so the interface{} type
+	// goes through without losing its interfaceness.
+	tBool      = bootstrapType("bool", (*bool)(nil), 1)
+	tInt       = bootstrapType("int", (*int)(nil), 2)
+	tUint      = bootstrapType("uint", (*uint)(nil), 3)
+	tFloat     = bootstrapType("float", (*float64)(nil), 4)
+	tBytes     = bootstrapType("bytes", (*[]byte)(nil), 5)
+	tString    = bootstrapType("string", (*string)(nil), 6)
+	tComplex   = bootstrapType("complex", (*complex128)(nil), 7)
+	tInterface = bootstrapType("interface", (*interface{})(nil), 8)
+	// Reserve some Ids for compatible expansion
+	tReserved7 = bootstrapType("_reserved1", (*struct{ r7 int })(nil), 9)
+	tReserved6 = bootstrapType("_reserved1", (*struct{ r6 int })(nil), 10)
+	tReserved5 = bootstrapType("_reserved1", (*struct{ r5 int })(nil), 11)
+	tReserved4 = bootstrapType("_reserved1", (*struct{ r4 int })(nil), 12)
+	tReserved3 = bootstrapType("_reserved1", (*struct{ r3 int })(nil), 13)
+	tReserved2 = bootstrapType("_reserved1", (*struct{ r2 int })(nil), 14)
+	tReserved1 = bootstrapType("_reserved1", (*struct{ r1 int })(nil), 15)
+)
+
+// Predefined because it's needed by the Decoder
+var tWireType = mustGetTypeInfo(reflect.TypeOf(wireType{})).id
+var wireTypeUserInfo *userTypeInfo // userTypeInfo of (*wireType)
+
+func init() {
+	// Some magic numbers to make sure there are no surprises.
+	checkId(16, tWireType)
+	checkId(17, mustGetTypeInfo(reflect.TypeOf(arrayType{})).id)
+	checkId(18, mustGetTypeInfo(reflect.TypeOf(CommonType{})).id)
+	checkId(19, mustGetTypeInfo(reflect.TypeOf(sliceType{})).id)
+	checkId(20, mustGetTypeInfo(reflect.TypeOf(structType{})).id)
+	checkId(21, mustGetTypeInfo(reflect.TypeOf(fieldType{})).id)
+	checkId(23, mustGetTypeInfo(reflect.TypeOf(mapType{})).id)
+
+	builtinIdToType = make(map[typeId]gobType)
+	for k, v := range idToType {
+		builtinIdToType[k] = v
+	}
+
+	// Move the id space upwards to allow for growth in the predefined world
+	// without breaking existing files.
+	if nextId > firstUserId {
+		panic(fmt.Sprintln("nextId too large:", nextId))
+	}
+	nextId = firstUserId
+	registerBasics()
+	wireTypeUserInfo = userType(reflect.TypeOf((*wireType)(nil)))
+}
+
+// Array type
+type arrayType struct {
+	CommonType
+	Elem typeId
+	Len  int
+}
+
+func newArrayType(name string) *arrayType {
+	a := &arrayType{CommonType{Name: name}, 0, 0}
+	return a
+}
+
+func (a *arrayType) init(elem gobType, len int) {
+	// Set our type id before evaluating the element's, in case it's our own.
+	setTypeId(a)
+	a.Elem = elem.id()
+	a.Len = len
+}
+
+func (a *arrayType) safeString(seen map[typeId]bool) string {
+	if seen[a.Id] {
+		return a.Name
+	}
+	seen[a.Id] = true
+	return fmt.Sprintf("[%d]%s", a.Len, a.Elem.gobType().safeString(seen))
+}
+
+func (a *arrayType) string() string { return a.safeString(make(map[typeId]bool)) }
+
+// GobEncoder type (something that implements the GobEncoder interface)
+type gobEncoderType struct {
+	CommonType
+}
+
+func newGobEncoderType(name string) *gobEncoderType {
+	g := &gobEncoderType{CommonType{Name: name}}
+	setTypeId(g)
+	return g
+}
+
+func (g *gobEncoderType) safeString(seen map[typeId]bool) string {
+	return g.Name
+}
+
+func (g *gobEncoderType) string() string { return g.Name }
+
+// Map type
+type mapType struct {
+	CommonType
+	Key  typeId
+	Elem typeId
+}
+
+func newMapType(name string) *mapType {
+	m := &mapType{CommonType{Name: name}, 0, 0}
+	return m
+}
+
+func (m *mapType) init(key, elem gobType) {
+	// Set our type id before evaluating the element's, in case it's our own.
+	setTypeId(m)
+	m.Key = key.id()
+	m.Elem = elem.id()
+}
+
+func (m *mapType) safeString(seen map[typeId]bool) string {
+	if seen[m.Id] {
+		return m.Name
+	}
+	seen[m.Id] = true
+	key := m.Key.gobType().safeString(seen)
+	elem := m.Elem.gobType().safeString(seen)
+	return fmt.Sprintf("map[%s]%s", key, elem)
+}
+
+func (m *mapType) string() string { return m.safeString(make(map[typeId]bool)) }
+
+// Slice type
+type sliceType struct {
+	CommonType
+	Elem typeId
+}
+
+func newSliceType(name string) *sliceType {
+	s := &sliceType{CommonType{Name: name}, 0}
+	return s
+}
+
+func (s *sliceType) init(elem gobType) {
+	// Set our type id before evaluating the element's, in case it's our own.
+	setTypeId(s)
+	s.Elem = elem.id()
+}
+
+func (s *sliceType) safeString(seen map[typeId]bool) string {
+	if seen[s.Id] {
+		return s.Name
+	}
+	seen[s.Id] = true
+	return fmt.Sprintf("[]%s", s.Elem.gobType().safeString(seen))
+}
+
+func (s *sliceType) string() string { return s.safeString(make(map[typeId]bool)) }
+
+// Struct type
+type fieldType struct {
+	Name string
+	Id   typeId
+}
+
+type structType struct {
+	CommonType
+	Field []*fieldType
+}
+
+func (s *structType) safeString(seen map[typeId]bool) string {
+	if s == nil {
+		return "<nil>"
+	}
+	if _, ok := seen[s.Id]; ok {
+		return s.Name
+	}
+	seen[s.Id] = true
+	str := s.Name + " = struct { "
+	for _, f := range s.Field {
+		str += fmt.Sprintf("%s %s; ", f.Name, f.Id.gobType().safeString(seen))
+	}
+	str += "}"
+	return str
+}
+
+func (s *structType) string() string { return s.safeString(make(map[typeId]bool)) }
+
+func newStructType(name string) *structType {
+	s := &structType{CommonType{Name: name}, nil}
+	// For historical reasons we set the id here rather than init.
+	// See the comment in newTypeObject for details.
+	setTypeId(s)
+	return s
+}
+
+// newTypeObject allocates a gobType for the reflection type rt.
+// Unless ut represents a GobEncoder, rt should be the base type
+// of ut.
+// This is only called from the encoding side. The decoding side
+// works through typeIds and userTypeInfos alone.
+func newTypeObject(name string, ut *userTypeInfo, rt reflect.Type) (gobType, error) {
+	// Does this type implement GobEncoder?
+	if ut.isGobEncoder {
+		return newGobEncoderType(name), nil
+	}
+	var err error
+	var type0, type1 gobType
+	defer func() {
+		if err != nil {
+			delete(types, rt)
+		}
+	}()
+	// Install the top-level type before the subtypes (e.g. struct before
+	// fields) so recursive types can be constructed safely.
+	switch t := rt; t.Kind() {
+	// All basic types are easy: they are predefined.
+	case reflect.Bool:
+		return tBool.gobType(), nil
+
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		return tInt.gobType(), nil
+
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+		return tUint.gobType(), nil
+
+	case reflect.Float32, reflect.Float64:
+		return tFloat.gobType(), nil
+
+	case reflect.Complex64, reflect.Complex128:
+		return tComplex.gobType(), nil
+
+	case reflect.String:
+		return tString.gobType(), nil
+
+	case reflect.Interface:
+		return tInterface.gobType(), nil
+
+	case reflect.Array:
+		at := newArrayType(name)
+		types[rt] = at
+		type0, err = getBaseType("", t.Elem())
+		if err != nil {
+			return nil, err
+		}
+		// Historical aside:
+		// For arrays, maps, and slices, we set the type id after the elements
+		// are constructed. This is to retain the order of type id allocation after
+		// a fix made to handle recursive types, which changed the order in
+		// which types are built.  Delaying the setting in this way preserves
+		// type ids while allowing recursive types to be described. Structs,
+		// done below, were already handling recursion correctly so they
+		// assign the top-level id before those of the field.
+		at.init(type0, t.Len())
+		return at, nil
+
+	case reflect.Map:
+		mt := newMapType(name)
+		types[rt] = mt
+		type0, err = getBaseType("", t.Key())
+		if err != nil {
+			return nil, err
+		}
+		type1, err = getBaseType("", t.Elem())
+		if err != nil {
+			return nil, err
+		}
+		mt.init(type0, type1)
+		return mt, nil
+
+	case reflect.Slice:
+		// []byte == []uint8 is a special case
+		if t.Elem().Kind() == reflect.Uint8 {
+			return tBytes.gobType(), nil
+		}
+		st := newSliceType(name)
+		types[rt] = st
+		type0, err = getBaseType(t.Elem().Name(), t.Elem())
+		if err != nil {
+			return nil, err
+		}
+		st.init(type0)
+		return st, nil
+
+	case reflect.Struct:
+		st := newStructType(name)
+		types[rt] = st
+		idToType[st.id()] = st
+		for i := 0; i < t.NumField(); i++ {
+			f := t.Field(i)
+			if !isExported(f.Name) {
+				continue
+			}
+			typ := userType(f.Type).base
+			tname := typ.Name()
+			if tname == "" {
+				t := userType(f.Type).base
+				tname = t.String()
+			}
+			gt, err := getBaseType(tname, f.Type)
+			if err != nil {
+				return nil, err
+			}
+			st.Field = append(st.Field, &fieldType{f.Name, gt.id()})
+		}
+		return st, nil
+
+	default:
+		return nil, errors.New("gob NewTypeObject can't handle type: " + rt.String())
+	}
+	return nil, nil
+}
+
+// isExported reports whether this is an exported - upper case - name.
+func isExported(name string) bool {
+	rune, _ := utf8.DecodeRuneInString(name)
+	return unicode.IsUpper(rune)
+}
+
+// getBaseType returns the Gob type describing the given reflect.Type's base type.
+// typeLock must be held.
+func getBaseType(name string, rt reflect.Type) (gobType, error) {
+	ut := userType(rt)
+	return getType(name, ut, ut.base)
+}
+
+// getType returns the Gob type describing the given reflect.Type.
+// Should be called only when handling GobEncoders/Decoders,
+// which may be pointers.  All other types are handled through the
+// base type, never a pointer.
+// typeLock must be held.
+func getType(name string, ut *userTypeInfo, rt reflect.Type) (gobType, error) {
+	typ, present := types[rt]
+	if present {
+		return typ, nil
+	}
+	typ, err := newTypeObject(name, ut, rt)
+	if err == nil {
+		types[rt] = typ
+	}
+	return typ, err
+}
+
+func checkId(want, got typeId) {
+	if want != got {
+		fmt.Fprintf(os.Stderr, "checkId: %d should be %d\n", int(got), int(want))
+		panic("bootstrap type wrong id: " + got.name() + " " + got.string() + " not " + want.string())
+	}
+}
+
+// used for building the basic types; called only from init().  the incoming
+// interface always refers to a pointer.
+func bootstrapType(name string, e interface{}, expect typeId) typeId {
+	rt := reflect.TypeOf(e).Elem()
+	_, present := types[rt]
+	if present {
+		panic("bootstrap type already present: " + name + ", " + rt.String())
+	}
+	typ := &CommonType{Name: name}
+	types[rt] = typ
+	setTypeId(typ)
+	checkId(expect, nextId)
+	userType(rt) // might as well cache it now
+	return nextId
+}
+
+// Representation of the information we send and receive about this type.
+// Each value we send is preceded by its type definition: an encoded int.
+// However, the very first time we send the value, we first send the pair
+// (-id, wireType).
+// For bootstrapping purposes, we assume that the recipient knows how
+// to decode a wireType; it is exactly the wireType struct here, interpreted
+// using the gob rules for sending a structure, except that we assume the
+// ids for wireType and structType etc. are known.  The relevant pieces
+// are built in encode.go's init() function.
+// To maintain binary compatibility, if you extend this type, always put
+// the new fields last.
+type wireType struct {
+	ArrayT      *arrayType
+	SliceT      *sliceType
+	StructT     *structType
+	MapT        *mapType
+	GobEncoderT *gobEncoderType
+}
+
+func (w *wireType) string() string {
+	const unknown = "unknown type"
+	if w == nil {
+		return unknown
+	}
+	switch {
+	case w.ArrayT != nil:
+		return w.ArrayT.Name
+	case w.SliceT != nil:
+		return w.SliceT.Name
+	case w.StructT != nil:
+		return w.StructT.Name
+	case w.MapT != nil:
+		return w.MapT.Name
+	case w.GobEncoderT != nil:
+		return w.GobEncoderT.Name
+	}
+	return unknown
+}
+
+type typeInfo struct {
+	id      typeId
+	encoder *encEngine
+	wire    *wireType
+}
+
+var typeInfoMap = make(map[reflect.Type]*typeInfo) // protected by typeLock
+
+// typeLock must be held.
+func getTypeInfo(ut *userTypeInfo) (*typeInfo, error) {
+	rt := ut.base
+	if ut.isGobEncoder {
+		// We want the user type, not the base type.
+		rt = ut.user
+	}
+	info, ok := typeInfoMap[rt]
+	if ok {
+		return info, nil
+	}
+	info = new(typeInfo)
+	gt, err := getBaseType(rt.Name(), rt)
+	if err != nil {
+		return nil, err
+	}
+	info.id = gt.id()
+
+	if ut.isGobEncoder {
+		userType, err := getType(rt.Name(), ut, rt)
+		if err != nil {
+			return nil, err
+		}
+		info.wire = &wireType{GobEncoderT: userType.id().gobType().(*gobEncoderType)}
+		typeInfoMap[ut.user] = info
+		return info, nil
+	}
+
+	t := info.id.gobType()
+	switch typ := rt; typ.Kind() {
+	case reflect.Array:
+		info.wire = &wireType{ArrayT: t.(*arrayType)}
+	case reflect.Map:
+		info.wire = &wireType{MapT: t.(*mapType)}
+	case reflect.Slice:
+		// []byte == []uint8 is a special case handled separately
+		if typ.Elem().Kind() != reflect.Uint8 {
+			info.wire = &wireType{SliceT: t.(*sliceType)}
+		}
+	case reflect.Struct:
+		info.wire = &wireType{StructT: t.(*structType)}
+	}
+	typeInfoMap[rt] = info
+	return info, nil
+}
+
+// Called only when a panic is acceptable and unexpected.
+func mustGetTypeInfo(rt reflect.Type) *typeInfo {
+	t, err := getTypeInfo(userType(rt))
+	if err != nil {
+		panic("getTypeInfo: " + err.Error())
+	}
+	return t
+}
+
+// GobEncoder is the interface describing data that provides its own
+// representation for encoding values for transmission to a GobDecoder.
+// A type that implements GobEncoder and GobDecoder has complete
+// control over the representation of its data and may therefore
+// contain things such as private fields, channels, and functions,
+// which are not usually transmissible in gob streams.
+//
+// Note: Since gobs can be stored permanently, It is good design
+// to guarantee the encoding used by a GobEncoder is stable as the
+// software evolves.  For instance, it might make sense for GobEncode
+// to include a version number in the encoding.
+type GobEncoder interface {
+	// GobEncode returns a byte slice representing the encoding of the
+	// receiver for transmission to a GobDecoder, usually of the same
+	// concrete type.
+	GobEncode() ([]byte, error)
+}
+
+// GobDecoder is the interface describing data that provides its own
+// routine for decoding transmitted values sent by a GobEncoder.
+type GobDecoder interface {
+	// GobDecode overwrites the receiver, which must be a pointer,
+	// with the value represented by the byte slice, which was written
+	// by GobEncode, usually for the same concrete type.
+	GobDecode([]byte) error
+}
+
+var (
+	nameToConcreteType = make(map[string]reflect.Type)
+	concreteTypeToName = make(map[reflect.Type]string)
+)
+
+// RegisterName is like Register but uses the provided name rather than the
+// type's default.
+func RegisterName(name string, value interface{}) {
+	if name == "" {
+		// reserved for nil
+		panic("attempt to register empty name")
+	}
+	ut := userType(reflect.TypeOf(value))
+	// Check for incompatible duplicates. The name must refer to the
+	// same user type, and vice versa.
+	if t, ok := nameToConcreteType[name]; ok && t != ut.user {
+		panic(fmt.Sprintf("gob: registering duplicate types for %q: %s != %s", name, t, ut.user))
+	}
+	if n, ok := concreteTypeToName[ut.base]; ok && n != name {
+		panic(fmt.Sprintf("gob: registering duplicate names for %s: %q != %q", ut.user, n, name))
+	}
+	// Store the name and type provided by the user....
+	nameToConcreteType[name] = reflect.TypeOf(value)
+	// but the flattened type in the type table, since that's what decode needs.
+	concreteTypeToName[ut.base] = name
+}
+
+// Register records a type, identified by a value for that type, under its
+// internal type name.  That name will identify the concrete type of a value
+// sent or received as an interface variable.  Only types that will be
+// transferred as implementations of interface values need to be registered.
+// Expecting to be used only during initialization, it panics if the mapping
+// between types and names is not a bijection.
+func Register(value interface{}) {
+	// Default to printed representation for unnamed types
+	rt := reflect.TypeOf(value)
+	name := rt.String()
+
+	// But for named types (or pointers to them), qualify with import path.
+	// Dereference one pointer looking for a named type.
+	star := ""
+	if rt.Name() == "" {
+		if pt := rt; pt.Kind() == reflect.Ptr {
+			star = "*"
+			rt = pt
+		}
+	}
+	if rt.Name() != "" {
+		if rt.PkgPath() == "" {
+			name = star + rt.Name()
+		} else {
+			name = star + rt.PkgPath() + "." + rt.Name()
+		}
+	}
+
+	RegisterName(name, value)
+}
+
+func registerBasics() {
+	Register(int(0))
+	Register(int8(0))
+	Register(int16(0))
+	Register(int32(0))
+	Register(int64(0))
+	Register(uint(0))
+	Register(uint8(0))
+	Register(uint16(0))
+	Register(uint32(0))
+	Register(uint64(0))
+	Register(float32(0))
+	Register(float64(0))
+	Register(complex64(0i))
+	Register(complex128(0i))
+	Register(uintptr(0))
+	Register(false)
+	Register("")
+	Register([]byte(nil))
+	Register([]int(nil))
+	Register([]int8(nil))
+	Register([]int16(nil))
+	Register([]int32(nil))
+	Register([]int64(nil))
+	Register([]uint(nil))
+	Register([]uint8(nil))
+	Register([]uint16(nil))
+	Register([]uint32(nil))
+	Register([]uint64(nil))
+	Register([]float32(nil))
+	Register([]float64(nil))
+	Register([]complex64(nil))
+	Register([]complex128(nil))
+	Register([]uintptr(nil))
+	Register([]bool(nil))
+	Register([]string(nil))
+}
diff --git a/libgo/go/encoding/gob/type_test.go b/libgo/go/encoding/gob/type_test.go
new file mode 100644
index 00000000000..42bdb4cf7bb
--- /dev/null
+++ b/libgo/go/encoding/gob/type_test.go
@@ -0,0 +1,161 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package gob
+
+import (
+	"reflect"
+	"testing"
+)
+
+type typeT struct {
+	id  typeId
+	str string
+}
+
+var basicTypes = []typeT{
+	{tBool, "bool"},
+	{tInt, "int"},
+	{tUint, "uint"},
+	{tFloat, "float"},
+	{tBytes, "bytes"},
+	{tString, "string"},
+}
+
+func getTypeUnlocked(name string, rt reflect.Type) gobType {
+	typeLock.Lock()
+	defer typeLock.Unlock()
+	t, err := getBaseType(name, rt)
+	if err != nil {
+		panic("getTypeUnlocked: " + err.Error())
+	}
+	return t
+}
+
+// Sanity checks
+func TestBasic(t *testing.T) {
+	for _, tt := range basicTypes {
+		if tt.id.string() != tt.str {
+			t.Errorf("checkType: expected %q got %s", tt.str, tt.id.string())
+		}
+		if tt.id == 0 {
+			t.Errorf("id for %q is zero", tt.str)
+		}
+	}
+}
+
+// Reregister some basic types to check registration is idempotent.
+func TestReregistration(t *testing.T) {
+	newtyp := getTypeUnlocked("int", reflect.TypeOf(int(0)))
+	if newtyp != tInt.gobType() {
+		t.Errorf("reregistration of %s got new type", newtyp.string())
+	}
+	newtyp = getTypeUnlocked("uint", reflect.TypeOf(uint(0)))
+	if newtyp != tUint.gobType() {
+		t.Errorf("reregistration of %s got new type", newtyp.string())
+	}
+	newtyp = getTypeUnlocked("string", reflect.TypeOf("hello"))
+	if newtyp != tString.gobType() {
+		t.Errorf("reregistration of %s got new type", newtyp.string())
+	}
+}
+
+func TestArrayType(t *testing.T) {
+	var a3 [3]int
+	a3int := getTypeUnlocked("foo", reflect.TypeOf(a3))
+	newa3int := getTypeUnlocked("bar", reflect.TypeOf(a3))
+	if a3int != newa3int {
+		t.Errorf("second registration of [3]int creates new type")
+	}
+	var a4 [4]int
+	a4int := getTypeUnlocked("goo", reflect.TypeOf(a4))
+	if a3int == a4int {
+		t.Errorf("registration of [3]int creates same type as [4]int")
+	}
+	var b3 [3]bool
+	a3bool := getTypeUnlocked("", reflect.TypeOf(b3))
+	if a3int == a3bool {
+		t.Errorf("registration of [3]bool creates same type as [3]int")
+	}
+	str := a3bool.string()
+	expected := "[3]bool"
+	if str != expected {
+		t.Errorf("array printed as %q; expected %q", str, expected)
+	}
+}
+
+func TestSliceType(t *testing.T) {
+	var s []int
+	sint := getTypeUnlocked("slice", reflect.TypeOf(s))
+	var news []int
+	newsint := getTypeUnlocked("slice1", reflect.TypeOf(news))
+	if sint != newsint {
+		t.Errorf("second registration of []int creates new type")
+	}
+	var b []bool
+	sbool := getTypeUnlocked("", reflect.TypeOf(b))
+	if sbool == sint {
+		t.Errorf("registration of []bool creates same type as []int")
+	}
+	str := sbool.string()
+	expected := "[]bool"
+	if str != expected {
+		t.Errorf("slice printed as %q; expected %q", str, expected)
+	}
+}
+
+func TestMapType(t *testing.T) {
+	var m map[string]int
+	mapStringInt := getTypeUnlocked("map", reflect.TypeOf(m))
+	var newm map[string]int
+	newMapStringInt := getTypeUnlocked("map1", reflect.TypeOf(newm))
+	if mapStringInt != newMapStringInt {
+		t.Errorf("second registration of map[string]int creates new type")
+	}
+	var b map[string]bool
+	mapStringBool := getTypeUnlocked("", reflect.TypeOf(b))
+	if mapStringBool == mapStringInt {
+		t.Errorf("registration of map[string]bool creates same type as map[string]int")
+	}
+	str := mapStringBool.string()
+	expected := "map[string]bool"
+	if str != expected {
+		t.Errorf("map printed as %q; expected %q", str, expected)
+	}
+}
+
+type Bar struct {
+	X string
+}
+
+// This structure has pointers and refers to itself, making it a good test case.
+type Foo struct {
+	A int
+	B int32 // will become int
+	C string
+	D []byte
+	E *float64    // will become float64
+	F ****float64 // will become float64
+	G *Bar
+	H *Bar // should not interpolate the definition of Bar again
+	I *Foo // will not explode
+}
+
+func TestStructType(t *testing.T) {
+	sstruct := getTypeUnlocked("Foo", reflect.TypeOf(Foo{}))
+	str := sstruct.string()
+	// If we can print it correctly, we built it correctly.
+	expected := "Foo = struct { A int; B int; C string; D bytes; E float; F float; G Bar = struct { X string; }; H Bar; I Foo; }"
+	if str != expected {
+		t.Errorf("struct printed as %q; expected %q", str, expected)
+	}
+}
+
+// Should be OK to register the same type multiple times, as long as they're
+// at the same level of indirection.
+func TestRegistration(t *testing.T) {
+	type T struct{ a int }
+	Register(new(T))
+	Register(new(T))
+}
diff --git a/libgo/go/encoding/json/decode.go b/libgo/go/encoding/json/decode.go
new file mode 100644
index 00000000000..41295d2d241
--- /dev/null
+++ b/libgo/go/encoding/json/decode.go
@@ -0,0 +1,939 @@
+// Copyright 2010 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Represents JSON data structure using native Go types: booleans, floats,
+// strings, arrays, and maps.
+
+package json
+
+import (
+	"encoding/base64"
+	"errors"
+	"reflect"
+	"runtime"
+	"strconv"
+	"strings"
+	"unicode"
+	"unicode/utf16"
+	"unicode/utf8"
+)
+
+// Unmarshal parses the JSON-encoded data and stores the result
+// in the value pointed to by v.
+//
+// Unmarshal uses the inverse of the encodings that
+// Marshal uses, allocating maps, slices, and pointers as necessary,
+// with the following additional rules:
+//
+// To unmarshal JSON into a pointer, Unmarshal first handles the case of
+// the JSON being the JSON literal null.  In that case, Unmarshal sets
+// the pointer to nil.  Otherwise, Unmarshal unmarshals the JSON into
+// the value pointed at by the pointer.  If the pointer is nil, Unmarshal
+// allocates a new value for it to point to.
+//
+// To unmarshal JSON into an interface value, Unmarshal unmarshals
+// the JSON into the concrete value contained in the interface value.
+// If the interface value is nil, that is, has no concrete value stored in it,
+// Unmarshal stores one of these in the interface value:
+//
+//	bool, for JSON booleans
+//	float64, for JSON numbers
+//	string, for JSON strings
+//	[]interface{}, for JSON arrays
+//	map[string]interface{}, for JSON objects
+//	nil for JSON null
+//
+// If a JSON value is not appropriate for a given target type,
+// or if a JSON number overflows the target type, Unmarshal
+// skips that field and completes the unmarshalling as best it can.
+// If no more serious errors are encountered, Unmarshal returns
+// an UnmarshalTypeError describing the earliest such error.
+//
+func Unmarshal(data []byte, v interface{}) error {
+	d := new(decodeState).init(data)
+
+	// Quick check for well-formedness.
+	// Avoids filling out half a data structure
+	// before discovering a JSON syntax error.
+	err := checkValid(data, &d.scan)
+	if err != nil {
+		return err
+	}
+
+	return d.unmarshal(v)
+}
+
+// Unmarshaler is the interface implemented by objects
+// that can unmarshal a JSON description of themselves.
+// The input can be assumed to be a valid JSON object
+// encoding.  UnmarshalJSON must copy the JSON data
+// if it wishes to retain the data after returning.
+type Unmarshaler interface {
+	UnmarshalJSON([]byte) error
+}
+
+// An UnmarshalTypeError describes a JSON value that was
+// not appropriate for a value of a specific Go type.
+type UnmarshalTypeError struct {
+	Value string       // description of JSON value - "bool", "array", "number -5"
+	Type  reflect.Type // type of Go value it could not be assigned to
+}
+
+func (e *UnmarshalTypeError) Error() string {
+	return "json: cannot unmarshal " + e.Value + " into Go value of type " + e.Type.String()
+}
+
+// An UnmarshalFieldError describes a JSON object key that
+// led to an unexported (and therefore unwritable) struct field.
+type UnmarshalFieldError struct {
+	Key   string
+	Type  reflect.Type
+	Field reflect.StructField
+}
+
+func (e *UnmarshalFieldError) Error() string {
+	return "json: cannot unmarshal object key " + strconv.Quote(e.Key) + " into unexported field " + e.Field.Name + " of type " + e.Type.String()
+}
+
+// An InvalidUnmarshalError describes an invalid argument passed to Unmarshal.
+// (The argument to Unmarshal must be a non-nil pointer.)
+type InvalidUnmarshalError struct {
+	Type reflect.Type
+}
+
+func (e *InvalidUnmarshalError) Error() string {
+	if e.Type == nil {
+		return "json: Unmarshal(nil)"
+	}
+
+	if e.Type.Kind() != reflect.Ptr {
+		return "json: Unmarshal(non-pointer " + e.Type.String() + ")"
+	}
+	return "json: Unmarshal(nil " + e.Type.String() + ")"
+}
+
+func (d *decodeState) unmarshal(v interface{}) (err error) {
+	defer func() {
+		if r := recover(); r != nil {
+			if _, ok := r.(runtime.Error); ok {
+				panic(r)
+			}
+			err = r.(error)
+		}
+	}()
+
+	rv := reflect.ValueOf(v)
+	pv := rv
+	if pv.Kind() != reflect.Ptr || pv.IsNil() {
+		return &InvalidUnmarshalError{reflect.TypeOf(v)}
+	}
+
+	d.scan.reset()
+	// We decode rv not pv.Elem because the Unmarshaler interface
+	// test must be applied at the top level of the value.
+	d.value(rv)
+	return d.savedError
+}
+
+// decodeState represents the state while decoding a JSON value.
+type decodeState struct {
+	data       []byte
+	off        int // read offset in data
+	scan       scanner
+	nextscan   scanner // for calls to nextValue
+	savedError error
+	tempstr    string // scratch space to avoid some allocations
+}
+
+// errPhase is used for errors that should not happen unless
+// there is a bug in the JSON decoder or something is editing
+// the data slice while the decoder executes.
+var errPhase = errors.New("JSON decoder out of sync - data changing underfoot?")
+
+func (d *decodeState) init(data []byte) *decodeState {
+	d.data = data
+	d.off = 0
+	d.savedError = nil
+	return d
+}
+
+// error aborts the decoding by panicking with err.
+func (d *decodeState) error(err error) {
+	panic(err)
+}
+
+// saveError saves the first err it is called with,
+// for reporting at the end of the unmarshal.
+func (d *decodeState) saveError(err error) {
+	if d.savedError == nil {
+		d.savedError = err
+	}
+}
+
+// next cuts off and returns the next full JSON value in d.data[d.off:].
+// The next value is known to be an object or array, not a literal.
+func (d *decodeState) next() []byte {
+	c := d.data[d.off]
+	item, rest, err := nextValue(d.data[d.off:], &d.nextscan)
+	if err != nil {
+		d.error(err)
+	}
+	d.off = len(d.data) - len(rest)
+
+	// Our scanner has seen the opening brace/bracket
+	// and thinks we're still in the middle of the object.
+	// invent a closing brace/bracket to get it out.
+	if c == '{' {
+		d.scan.step(&d.scan, '}')
+	} else {
+		d.scan.step(&d.scan, ']')
+	}
+
+	return item
+}
+
+// scanWhile processes bytes in d.data[d.off:] until it
+// receives a scan code not equal to op.
+// It updates d.off and returns the new scan code.
+func (d *decodeState) scanWhile(op int) int {
+	var newOp int
+	for {
+		if d.off >= len(d.data) {
+			newOp = d.scan.eof()
+			d.off = len(d.data) + 1 // mark processed EOF with len+1
+		} else {
+			c := int(d.data[d.off])
+			d.off++
+			newOp = d.scan.step(&d.scan, c)
+		}
+		if newOp != op {
+			break
+		}
+	}
+	return newOp
+}
+
+// value decodes a JSON value from d.data[d.off:] into the value.
+// it updates d.off to point past the decoded value.
+func (d *decodeState) value(v reflect.Value) {
+	if !v.IsValid() {
+		_, rest, err := nextValue(d.data[d.off:], &d.nextscan)
+		if err != nil {
+			d.error(err)
+		}
+		d.off = len(d.data) - len(rest)
+
+		// d.scan thinks we're still at the beginning of the item.
+		// Feed in an empty string - the shortest, simplest value -
+		// so that it knows we got to the end of the value.
+		if d.scan.step == stateRedo {
+			panic("redo")
+		}
+		d.scan.step(&d.scan, '"')
+		d.scan.step(&d.scan, '"')
+		return
+	}
+
+	switch op := d.scanWhile(scanSkipSpace); op {
+	default:
+		d.error(errPhase)
+
+	case scanBeginArray:
+		d.array(v)
+
+	case scanBeginObject:
+		d.object(v)
+
+	case scanBeginLiteral:
+		d.literal(v)
+	}
+}
+
+// indirect walks down v allocating pointers as needed,
+// until it gets to a non-pointer.
+// if it encounters an Unmarshaler, indirect stops and returns that.
+// if decodingNull is true, indirect stops at the last pointer so it can be set to nil.
+func (d *decodeState) indirect(v reflect.Value, decodingNull bool) (Unmarshaler, reflect.Value) {
+	// If v is a named type and is addressable,
+	// start with its address, so that if the type has pointer methods,
+	// we find them.
+	if v.Kind() != reflect.Ptr && v.Type().Name() != "" && v.CanAddr() {
+		v = v.Addr()
+	}
+	for {
+		var isUnmarshaler bool
+		if v.Type().NumMethod() > 0 {
+			// Remember that this is an unmarshaler,
+			// but wait to return it until after allocating
+			// the pointer (if necessary).
+			_, isUnmarshaler = v.Interface().(Unmarshaler)
+		}
+
+		if iv := v; iv.Kind() == reflect.Interface && !iv.IsNil() {
+			v = iv.Elem()
+			continue
+		}
+
+		pv := v
+		if pv.Kind() != reflect.Ptr {
+			break
+		}
+
+		if pv.Elem().Kind() != reflect.Ptr && decodingNull && pv.CanSet() {
+			return nil, pv
+		}
+		if pv.IsNil() {
+			pv.Set(reflect.New(pv.Type().Elem()))
+		}
+		if isUnmarshaler {
+			// Using v.Interface().(Unmarshaler)
+			// here means that we have to use a pointer
+			// as the struct field.  We cannot use a value inside
+			// a pointer to a struct, because in that case
+			// v.Interface() is the value (x.f) not the pointer (&x.f).
+			// This is an unfortunate consequence of reflect.
+			// An alternative would be to look up the
+			// UnmarshalJSON method and return a FuncValue.
+			return v.Interface().(Unmarshaler), reflect.Value{}
+		}
+		v = pv.Elem()
+	}
+	return nil, v
+}
+
+// array consumes an array from d.data[d.off-1:], decoding into the value v.
+// the first byte of the array ('[') has been read already.
+func (d *decodeState) array(v reflect.Value) {
+	// Check for unmarshaler.
+	unmarshaler, pv := d.indirect(v, false)
+	if unmarshaler != nil {
+		d.off--
+		err := unmarshaler.UnmarshalJSON(d.next())
+		if err != nil {
+			d.error(err)
+		}
+		return
+	}
+	v = pv
+
+	// Decoding into nil interface?  Switch to non-reflect code.
+	iv := v
+	ok := iv.Kind() == reflect.Interface
+	if ok {
+		iv.Set(reflect.ValueOf(d.arrayInterface()))
+		return
+	}
+
+	// Check type of target.
+	av := v
+	if av.Kind() != reflect.Array && av.Kind() != reflect.Slice {
+		d.saveError(&UnmarshalTypeError{"array", v.Type()})
+		d.off--
+		d.next()
+		return
+	}
+
+	sv := v
+
+	i := 0
+	for {
+		// Look ahead for ] - can only happen on first iteration.
+		op := d.scanWhile(scanSkipSpace)
+		if op == scanEndArray {
+			break
+		}
+
+		// Back up so d.value can have the byte we just read.
+		d.off--
+		d.scan.undo(op)
+
+		// Get element of array, growing if necessary.
+		if i >= av.Cap() && sv.IsValid() {
+			newcap := sv.Cap() + sv.Cap()/2
+			if newcap < 4 {
+				newcap = 4
+			}
+			newv := reflect.MakeSlice(sv.Type(), sv.Len(), newcap)
+			reflect.Copy(newv, sv)
+			sv.Set(newv)
+		}
+		if i >= av.Len() && sv.IsValid() {
+			// Must be slice; gave up on array during i >= av.Cap().
+			sv.SetLen(i + 1)
+		}
+
+		// Decode into element.
+		if i < av.Len() {
+			d.value(av.Index(i))
+		} else {
+			// Ran out of fixed array: skip.
+			d.value(reflect.Value{})
+		}
+		i++
+
+		// Next token must be , or ].
+		op = d.scanWhile(scanSkipSpace)
+		if op == scanEndArray {
+			break
+		}
+		if op != scanArrayValue {
+			d.error(errPhase)
+		}
+	}
+	if i < av.Len() {
+		if !sv.IsValid() {
+			// Array.  Zero the rest.
+			z := reflect.Zero(av.Type().Elem())
+			for ; i < av.Len(); i++ {
+				av.Index(i).Set(z)
+			}
+		} else {
+			sv.SetLen(i)
+		}
+	}
+}
+
+// object consumes an object from d.data[d.off-1:], decoding into the value v.
+// the first byte of the object ('{') has been read already.
+func (d *decodeState) object(v reflect.Value) {
+	// Check for unmarshaler.
+	unmarshaler, pv := d.indirect(v, false)
+	if unmarshaler != nil {
+		d.off--
+		err := unmarshaler.UnmarshalJSON(d.next())
+		if err != nil {
+			d.error(err)
+		}
+		return
+	}
+	v = pv
+
+	// Decoding into nil interface?  Switch to non-reflect code.
+	iv := v
+	if iv.Kind() == reflect.Interface {
+		iv.Set(reflect.ValueOf(d.objectInterface()))
+		return
+	}
+
+	// Check type of target: struct or map[string]T
+	var (
+		mv reflect.Value
+		sv reflect.Value
+	)
+	switch v.Kind() {
+	case reflect.Map:
+		// map must have string type
+		t := v.Type()
+		if t.Key() != reflect.TypeOf("") {
+			d.saveError(&UnmarshalTypeError{"object", v.Type()})
+			break
+		}
+		mv = v
+		if mv.IsNil() {
+			mv.Set(reflect.MakeMap(t))
+		}
+	case reflect.Struct:
+		sv = v
+	default:
+		d.saveError(&UnmarshalTypeError{"object", v.Type()})
+	}
+
+	if !mv.IsValid() && !sv.IsValid() {
+		d.off--
+		d.next() // skip over { } in input
+		return
+	}
+
+	var mapElem reflect.Value
+
+	for {
+		// Read opening " of string key or closing }.
+		op := d.scanWhile(scanSkipSpace)
+		if op == scanEndObject {
+			// closing } - can only happen on first iteration.
+			break
+		}
+		if op != scanBeginLiteral {
+			d.error(errPhase)
+		}
+
+		// Read string key.
+		start := d.off - 1
+		op = d.scanWhile(scanContinue)
+		item := d.data[start : d.off-1]
+		key, ok := unquote(item)
+		if !ok {
+			d.error(errPhase)
+		}
+
+		// Figure out field corresponding to key.
+		var subv reflect.Value
+		destring := false // whether the value is wrapped in a string to be decoded first
+
+		if mv.IsValid() {
+			elemType := mv.Type().Elem()
+			if !mapElem.IsValid() {
+				mapElem = reflect.New(elemType).Elem()
+			} else {
+				mapElem.Set(reflect.Zero(elemType))
+			}
+			subv = mapElem
+		} else {
+			var f reflect.StructField
+			var ok bool
+			st := sv.Type()
+			for i := 0; i < sv.NumField(); i++ {
+				sf := st.Field(i)
+				tag := sf.Tag.Get("json")
+				if tag == "-" {
+					// Pretend this field doesn't exist.
+					continue
+				}
+				// First, tag match
+				tagName, _ := parseTag(tag)
+				if tagName == key {
+					f = sf
+					ok = true
+					break // no better match possible
+				}
+				// Second, exact field name match
+				if sf.Name == key {
+					f = sf
+					ok = true
+				}
+				// Third, case-insensitive field name match,
+				// but only if a better match hasn't already been seen
+				if !ok && strings.EqualFold(sf.Name, key) {
+					f = sf
+					ok = true
+				}
+			}
+
+			// Extract value; name must be exported.
+			if ok {
+				if f.PkgPath != "" {
+					d.saveError(&UnmarshalFieldError{key, st, f})
+				} else {
+					subv = sv.FieldByIndex(f.Index)
+				}
+				_, opts := parseTag(f.Tag.Get("json"))
+				destring = opts.Contains("string")
+			}
+		}
+
+		// Read : before value.
+		if op == scanSkipSpace {
+			op = d.scanWhile(scanSkipSpace)
+		}
+		if op != scanObjectKey {
+			d.error(errPhase)
+		}
+
+		// Read value.
+		if destring {
+			d.value(reflect.ValueOf(&d.tempstr))
+			d.literalStore([]byte(d.tempstr), subv)
+		} else {
+			d.value(subv)
+		}
+		// Write value back to map;
+		// if using struct, subv points into struct already.
+		if mv.IsValid() {
+			mv.SetMapIndex(reflect.ValueOf(key), subv)
+		}
+
+		// Next token must be , or }.
+		op = d.scanWhile(scanSkipSpace)
+		if op == scanEndObject {
+			break
+		}
+		if op != scanObjectValue {
+			d.error(errPhase)
+		}
+	}
+}
+
+// literal consumes a literal from d.data[d.off-1:], decoding into the value v.
+// The first byte of the literal has been read already
+// (that's how the caller knows it's a literal).
+func (d *decodeState) literal(v reflect.Value) {
+	// All bytes inside literal return scanContinue op code.
+	start := d.off - 1
+	op := d.scanWhile(scanContinue)
+
+	// Scan read one byte too far; back up.
+	d.off--
+	d.scan.undo(op)
+
+	d.literalStore(d.data[start:d.off], v)
+}
+
+// literalStore decodes a literal stored in item into v.
+func (d *decodeState) literalStore(item []byte, v reflect.Value) {
+	// Check for unmarshaler.
+	wantptr := item[0] == 'n' // null
+	unmarshaler, pv := d.indirect(v, wantptr)
+	if unmarshaler != nil {
+		err := unmarshaler.UnmarshalJSON(item)
+		if err != nil {
+			d.error(err)
+		}
+		return
+	}
+	v = pv
+
+	switch c := item[0]; c {
+	case 'n': // null
+		switch v.Kind() {
+		default:
+			d.saveError(&UnmarshalTypeError{"null", v.Type()})
+		case reflect.Interface, reflect.Ptr, reflect.Map, reflect.Slice:
+			v.Set(reflect.Zero(v.Type()))
+		}
+
+	case 't', 'f': // true, false
+		value := c == 't'
+		switch v.Kind() {
+		default:
+			d.saveError(&UnmarshalTypeError{"bool", v.Type()})
+		case reflect.Bool:
+			v.SetBool(value)
+		case reflect.Interface:
+			v.Set(reflect.ValueOf(value))
+		}
+
+	case '"': // string
+		s, ok := unquoteBytes(item)
+		if !ok {
+			d.error(errPhase)
+		}
+		switch v.Kind() {
+		default:
+			d.saveError(&UnmarshalTypeError{"string", v.Type()})
+		case reflect.Slice:
+			if v.Type() != byteSliceType {
+				d.saveError(&UnmarshalTypeError{"string", v.Type()})
+				break
+			}
+			b := make([]byte, base64.StdEncoding.DecodedLen(len(s)))
+			n, err := base64.StdEncoding.Decode(b, s)
+			if err != nil {
+				d.saveError(err)
+				break
+			}
+			v.Set(reflect.ValueOf(b[0:n]))
+		case reflect.String:
+			v.SetString(string(s))
+		case reflect.Interface:
+			v.Set(reflect.ValueOf(string(s)))
+		}
+
+	default: // number
+		if c != '-' && (c < '0' || c > '9') {
+			d.error(errPhase)
+		}
+		s := string(item)
+		switch v.Kind() {
+		default:
+			d.error(&UnmarshalTypeError{"number", v.Type()})
+		case reflect.Interface:
+			n, err := strconv.Atof64(s)
+			if err != nil {
+				d.saveError(&UnmarshalTypeError{"number " + s, v.Type()})
+				break
+			}
+			v.Set(reflect.ValueOf(n))
+
+		case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+			n, err := strconv.Atoi64(s)
+			if err != nil || v.OverflowInt(n) {
+				d.saveError(&UnmarshalTypeError{"number " + s, v.Type()})
+				break
+			}
+			v.SetInt(n)
+
+		case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+			n, err := strconv.Atoui64(s)
+			if err != nil || v.OverflowUint(n) {
+				d.saveError(&UnmarshalTypeError{"number " + s, v.Type()})
+				break
+			}
+			v.SetUint(n)
+
+		case reflect.Float32, reflect.Float64:
+			n, err := strconv.AtofN(s, v.Type().Bits())
+			if err != nil || v.OverflowFloat(n) {
+				d.saveError(&UnmarshalTypeError{"number " + s, v.Type()})
+				break
+			}
+			v.SetFloat(n)
+		}
+	}
+}
+
+// The xxxInterface routines build up a value to be stored
+// in an empty interface.  They are not strictly necessary,
+// but they avoid the weight of reflection in this common case.
+
+// valueInterface is like value but returns interface{}
+func (d *decodeState) valueInterface() interface{} {
+	switch d.scanWhile(scanSkipSpace) {
+	default:
+		d.error(errPhase)
+	case scanBeginArray:
+		return d.arrayInterface()
+	case scanBeginObject:
+		return d.objectInterface()
+	case scanBeginLiteral:
+		return d.literalInterface()
+	}
+	panic("unreachable")
+}
+
+// arrayInterface is like array but returns []interface{}.
+func (d *decodeState) arrayInterface() []interface{} {
+	var v []interface{}
+	for {
+		// Look ahead for ] - can only happen on first iteration.
+		op := d.scanWhile(scanSkipSpace)
+		if op == scanEndArray {
+			break
+		}
+
+		// Back up so d.value can have the byte we just read.
+		d.off--
+		d.scan.undo(op)
+
+		v = append(v, d.valueInterface())
+
+		// Next token must be , or ].
+		op = d.scanWhile(scanSkipSpace)
+		if op == scanEndArray {
+			break
+		}
+		if op != scanArrayValue {
+			d.error(errPhase)
+		}
+	}
+	return v
+}
+
+// objectInterface is like object but returns map[string]interface{}.
+func (d *decodeState) objectInterface() map[string]interface{} {
+	m := make(map[string]interface{})
+	for {
+		// Read opening " of string key or closing }.
+		op := d.scanWhile(scanSkipSpace)
+		if op == scanEndObject {
+			// closing } - can only happen on first iteration.
+			break
+		}
+		if op != scanBeginLiteral {
+			d.error(errPhase)
+		}
+
+		// Read string key.
+		start := d.off - 1
+		op = d.scanWhile(scanContinue)
+		item := d.data[start : d.off-1]
+		key, ok := unquote(item)
+		if !ok {
+			d.error(errPhase)
+		}
+
+		// Read : before value.
+		if op == scanSkipSpace {
+			op = d.scanWhile(scanSkipSpace)
+		}
+		if op != scanObjectKey {
+			d.error(errPhase)
+		}
+
+		// Read value.
+		m[key] = d.valueInterface()
+
+		// Next token must be , or }.
+		op = d.scanWhile(scanSkipSpace)
+		if op == scanEndObject {
+			break
+		}
+		if op != scanObjectValue {
+			d.error(errPhase)
+		}
+	}
+	return m
+}
+
+// literalInterface is like literal but returns an interface value.
+func (d *decodeState) literalInterface() interface{} {
+	// All bytes inside literal return scanContinue op code.
+	start := d.off - 1
+	op := d.scanWhile(scanContinue)
+
+	// Scan read one byte too far; back up.
+	d.off--
+	d.scan.undo(op)
+	item := d.data[start:d.off]
+
+	switch c := item[0]; c {
+	case 'n': // null
+		return nil
+
+	case 't', 'f': // true, false
+		return c == 't'
+
+	case '"': // string
+		s, ok := unquote(item)
+		if !ok {
+			d.error(errPhase)
+		}
+		return s
+
+	default: // number
+		if c != '-' && (c < '0' || c > '9') {
+			d.error(errPhase)
+		}
+		n, err := strconv.Atof64(string(item))
+		if err != nil {
+			d.saveError(&UnmarshalTypeError{"number " + string(item), reflect.TypeOf(0.0)})
+		}
+		return n
+	}
+	panic("unreachable")
+}
+
+// getu4 decodes \uXXXX from the beginning of s, returning the hex value,
+// or it returns -1.
+func getu4(s []byte) rune {
+	if len(s) < 6 || s[0] != '\\' || s[1] != 'u' {
+		return -1
+	}
+	r, err := strconv.Btoui64(string(s[2:6]), 16)
+	if err != nil {
+		return -1
+	}
+	return rune(r)
+}
+
+// unquote converts a quoted JSON string literal s into an actual string t.
+// The rules are different than for Go, so cannot use strconv.Unquote.
+func unquote(s []byte) (t string, ok bool) {
+	s, ok = unquoteBytes(s)
+	t = string(s)
+	return
+}
+
+func unquoteBytes(s []byte) (t []byte, ok bool) {
+	if len(s) < 2 || s[0] != '"' || s[len(s)-1] != '"' {
+		return
+	}
+	s = s[1 : len(s)-1]
+
+	// Check for unusual characters. If there are none,
+	// then no unquoting is needed, so return a slice of the
+	// original bytes.
+	r := 0
+	for r < len(s) {
+		c := s[r]
+		if c == '\\' || c == '"' || c < ' ' {
+			break
+		}
+		if c < utf8.RuneSelf {
+			r++
+			continue
+		}
+		rr, size := utf8.DecodeRune(s[r:])
+		if rr == utf8.RuneError && size == 1 {
+			break
+		}
+		r += size
+	}
+	if r == len(s) {
+		return s, true
+	}
+
+	b := make([]byte, len(s)+2*utf8.UTFMax)
+	w := copy(b, s[0:r])
+	for r < len(s) {
+		// Out of room?  Can only happen if s is full of
+		// malformed UTF-8 and we're replacing each
+		// byte with RuneError.
+		if w >= len(b)-2*utf8.UTFMax {
+			nb := make([]byte, (len(b)+utf8.UTFMax)*2)
+			copy(nb, b[0:w])
+			b = nb
+		}
+		switch c := s[r]; {
+		case c == '\\':
+			r++
+			if r >= len(s) {
+				return
+			}
+			switch s[r] {
+			default:
+				return
+			case '"', '\\', '/', '\'':
+				b[w] = s[r]
+				r++
+				w++
+			case 'b':
+				b[w] = '\b'
+				r++
+				w++
+			case 'f':
+				b[w] = '\f'
+				r++
+				w++
+			case 'n':
+				b[w] = '\n'
+				r++
+				w++
+			case 'r':
+				b[w] = '\r'
+				r++
+				w++
+			case 't':
+				b[w] = '\t'
+				r++
+				w++
+			case 'u':
+				r--
+				rr := getu4(s[r:])
+				if rr < 0 {
+					return
+				}
+				r += 6
+				if utf16.IsSurrogate(rr) {
+					rr1 := getu4(s[r:])
+					if dec := utf16.DecodeRune(rr, rr1); dec != unicode.ReplacementChar {
+						// A valid pair; consume.
+						r += 6
+						w += utf8.EncodeRune(b[w:], dec)
+						break
+					}
+					// Invalid surrogate; fall back to replacement rune.
+					rr = unicode.ReplacementChar
+				}
+				w += utf8.EncodeRune(b[w:], rr)
+			}
+
+		// Quote, control characters are invalid.
+		case c == '"', c < ' ':
+			return
+
+		// ASCII
+		case c < utf8.RuneSelf:
+			b[w] = c
+			r++
+			w++
+
+		// Coerce to well-formed UTF-8.
+		default:
+			rr, size := utf8.DecodeRune(s[r:])
+			r += size
+			w += utf8.EncodeRune(b[w:], rr)
+		}
+	}
+	return b[0:w], true
+}
diff --git a/libgo/go/encoding/json/decode_test.go b/libgo/go/encoding/json/decode_test.go
new file mode 100644
index 00000000000..bd4326a0cd7
--- /dev/null
+++ b/libgo/go/encoding/json/decode_test.go
@@ -0,0 +1,564 @@
+// Copyright 2010 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package json
+
+import (
+	"bytes"
+	"reflect"
+	"strings"
+	"testing"
+)
+
+type T struct {
+	X string
+	Y int
+	Z int `json:"-"`
+}
+
+type tx struct {
+	x int
+}
+
+var txType = reflect.TypeOf((*tx)(nil)).Elem()
+
+// A type that can unmarshal itself.
+
+type unmarshaler struct {
+	T bool
+}
+
+func (u *unmarshaler) UnmarshalJSON(b []byte) error {
+	*u = unmarshaler{true} // All we need to see that UnmarshalJson is called.
+	return nil
+}
+
+type ustruct struct {
+	M unmarshaler
+}
+
+var (
+	um0, um1 unmarshaler // target2 of unmarshaling
+	ump      = &um1
+	umtrue   = unmarshaler{true}
+	umslice  = []unmarshaler{{true}}
+	umslicep = new([]unmarshaler)
+	umstruct = ustruct{unmarshaler{true}}
+)
+
+type unmarshalTest struct {
+	in  string
+	ptr interface{}
+	out interface{}
+	err error
+}
+
+var unmarshalTests = []unmarshalTest{
+	// basic types
+	{`true`, new(bool), true, nil},
+	{`1`, new(int), 1, nil},
+	{`1.2`, new(float64), 1.2, nil},
+	{`-5`, new(int16), int16(-5), nil},
+	{`"a\u1234"`, new(string), "a\u1234", nil},
+	{`"http:\/\/"`, new(string), "http://", nil},
+	{`"g-clef: \uD834\uDD1E"`, new(string), "g-clef: \U0001D11E", nil},
+	{`"invalid: \uD834x\uDD1E"`, new(string), "invalid: \uFFFDx\uFFFD", nil},
+	{"null", new(interface{}), nil, nil},
+	{`{"X": [1,2,3], "Y": 4}`, new(T), T{Y: 4}, &UnmarshalTypeError{"array", reflect.TypeOf("")}},
+	{`{"x": 1}`, new(tx), tx{}, &UnmarshalFieldError{"x", txType, txType.Field(0)}},
+
+	// Z has a "-" tag.
+	{`{"Y": 1, "Z": 2}`, new(T), T{Y: 1}, nil},
+
+	// syntax errors
+	{`{"X": "foo", "Y"}`, nil, nil, &SyntaxError{"invalid character '}' after object key", 17}},
+
+	// composite tests
+	{allValueIndent, new(All), allValue, nil},
+	{allValueCompact, new(All), allValue, nil},
+	{allValueIndent, new(*All), &allValue, nil},
+	{allValueCompact, new(*All), &allValue, nil},
+	{pallValueIndent, new(All), pallValue, nil},
+	{pallValueCompact, new(All), pallValue, nil},
+	{pallValueIndent, new(*All), &pallValue, nil},
+	{pallValueCompact, new(*All), &pallValue, nil},
+
+	// unmarshal interface test
+	{`{"T":false}`, &um0, umtrue, nil}, // use "false" so test will fail if custom unmarshaler is not called
+	{`{"T":false}`, &ump, &umtrue, nil},
+	{`[{"T":false}]`, &umslice, umslice, nil},
+	{`[{"T":false}]`, &umslicep, &umslice, nil},
+	{`{"M":{"T":false}}`, &umstruct, umstruct, nil},
+}
+
+func TestMarshal(t *testing.T) {
+	b, err := Marshal(allValue)
+	if err != nil {
+		t.Fatalf("Marshal allValue: %v", err)
+	}
+	if string(b) != allValueCompact {
+		t.Errorf("Marshal allValueCompact")
+		diff(t, b, []byte(allValueCompact))
+		return
+	}
+
+	b, err = Marshal(pallValue)
+	if err != nil {
+		t.Fatalf("Marshal pallValue: %v", err)
+	}
+	if string(b) != pallValueCompact {
+		t.Errorf("Marshal pallValueCompact")
+		diff(t, b, []byte(pallValueCompact))
+		return
+	}
+}
+
+func TestMarshalBadUTF8(t *testing.T) {
+	s := "hello\xffworld"
+	b, err := Marshal(s)
+	if err == nil {
+		t.Fatal("Marshal bad UTF8: no error")
+	}
+	if len(b) != 0 {
+		t.Fatal("Marshal returned data")
+	}
+	if _, ok := err.(*InvalidUTF8Error); !ok {
+		t.Fatalf("Marshal did not return InvalidUTF8Error: %T %v", err, err)
+	}
+}
+
+func TestUnmarshal(t *testing.T) {
+	for i, tt := range unmarshalTests {
+		var scan scanner
+		in := []byte(tt.in)
+		if err := checkValid(in, &scan); err != nil {
+			if !reflect.DeepEqual(err, tt.err) {
+				t.Errorf("#%d: checkValid: %#v", i, err)
+				continue
+			}
+		}
+		if tt.ptr == nil {
+			continue
+		}
+		// v = new(right-type)
+		v := reflect.New(reflect.TypeOf(tt.ptr).Elem())
+		if err := Unmarshal([]byte(in), v.Interface()); !reflect.DeepEqual(err, tt.err) {
+			t.Errorf("#%d: %v want %v", i, err, tt.err)
+			continue
+		}
+		if !reflect.DeepEqual(v.Elem().Interface(), tt.out) {
+			t.Errorf("#%d: mismatch\nhave: %#+v\nwant: %#+v", i, v.Elem().Interface(), tt.out)
+			data, _ := Marshal(v.Elem().Interface())
+			println(string(data))
+			data, _ = Marshal(tt.out)
+			println(string(data))
+			continue
+		}
+	}
+}
+
+func TestUnmarshalMarshal(t *testing.T) {
+	initBig()
+	var v interface{}
+	if err := Unmarshal(jsonBig, &v); err != nil {
+		t.Fatalf("Unmarshal: %v", err)
+	}
+	b, err := Marshal(v)
+	if err != nil {
+		t.Fatalf("Marshal: %v", err)
+	}
+	if bytes.Compare(jsonBig, b) != 0 {
+		t.Errorf("Marshal jsonBig")
+		diff(t, b, jsonBig)
+		return
+	}
+}
+
+func TestLargeByteSlice(t *testing.T) {
+	s0 := make([]byte, 2000)
+	for i := range s0 {
+		s0[i] = byte(i)
+	}
+	b, err := Marshal(s0)
+	if err != nil {
+		t.Fatalf("Marshal: %v", err)
+	}
+	var s1 []byte
+	if err := Unmarshal(b, &s1); err != nil {
+		t.Fatalf("Unmarshal: %v", err)
+	}
+	if bytes.Compare(s0, s1) != 0 {
+		t.Errorf("Marshal large byte slice")
+		diff(t, s0, s1)
+	}
+}
+
+type Xint struct {
+	X int
+}
+
+func TestUnmarshalInterface(t *testing.T) {
+	var xint Xint
+	var i interface{} = &xint
+	if err := Unmarshal([]byte(`{"X":1}`), &i); err != nil {
+		t.Fatalf("Unmarshal: %v", err)
+	}
+	if xint.X != 1 {
+		t.Fatalf("Did not write to xint")
+	}
+}
+
+func TestUnmarshalPtrPtr(t *testing.T) {
+	var xint Xint
+	pxint := &xint
+	if err := Unmarshal([]byte(`{"X":1}`), &pxint); err != nil {
+		t.Fatalf("Unmarshal: %v", err)
+	}
+	if xint.X != 1 {
+		t.Fatalf("Did not write to xint")
+	}
+}
+
+func TestEscape(t *testing.T) {
+	const input = `"foobar"<html>`
+	const expected = `"\"foobar\"\u003chtml\u003e"`
+	b, err := Marshal(input)
+	if err != nil {
+		t.Fatalf("Marshal error: %v", err)
+	}
+	if s := string(b); s != expected {
+		t.Errorf("Encoding of [%s] was [%s], want [%s]", input, s, expected)
+	}
+}
+
+func TestHTMLEscape(t *testing.T) {
+	b, err := MarshalForHTML("foobarbaz<>&quux")
+	if err != nil {
+		t.Fatalf("MarshalForHTML error: %v", err)
+	}
+	if !bytes.Equal(b, []byte(`"foobarbaz\u003c\u003e\u0026quux"`)) {
+		t.Fatalf("Unexpected encoding of \"<>&\": %s", b)
+	}
+}
+
+func noSpace(c rune) rune {
+	if isSpace(c) {
+		return -1
+	}
+	return c
+}
+
+type All struct {
+	Bool    bool
+	Int     int
+	Int8    int8
+	Int16   int16
+	Int32   int32
+	Int64   int64
+	Uint    uint
+	Uint8   uint8
+	Uint16  uint16
+	Uint32  uint32
+	Uint64  uint64
+	Uintptr uintptr
+	Float32 float32
+	Float64 float64
+
+	Foo  string `json:"bar"`
+	Foo2 string `json:"bar2,dummyopt"`
+
+	IntStr int64 `json:",string"`
+
+	PBool    *bool
+	PInt     *int
+	PInt8    *int8
+	PInt16   *int16
+	PInt32   *int32
+	PInt64   *int64
+	PUint    *uint
+	PUint8   *uint8
+	PUint16  *uint16
+	PUint32  *uint32
+	PUint64  *uint64
+	PUintptr *uintptr
+	PFloat32 *float32
+	PFloat64 *float64
+
+	String  string
+	PString *string
+
+	Map   map[string]Small
+	MapP  map[string]*Small
+	PMap  *map[string]Small
+	PMapP *map[string]*Small
+
+	EmptyMap map[string]Small
+	NilMap   map[string]Small
+
+	Slice   []Small
+	SliceP  []*Small
+	PSlice  *[]Small
+	PSliceP *[]*Small
+
+	EmptySlice []Small
+	NilSlice   []Small
+
+	StringSlice []string
+	ByteSlice   []byte
+
+	Small   Small
+	PSmall  *Small
+	PPSmall **Small
+
+	Interface  interface{}
+	PInterface *interface{}
+
+	unexported int
+}
+
+type Small struct {
+	Tag string
+}
+
+var allValue = All{
+	Bool:    true,
+	Int:     2,
+	Int8:    3,
+	Int16:   4,
+	Int32:   5,
+	Int64:   6,
+	Uint:    7,
+	Uint8:   8,
+	Uint16:  9,
+	Uint32:  10,
+	Uint64:  11,
+	Uintptr: 12,
+	Float32: 14.1,
+	Float64: 15.1,
+	Foo:     "foo",
+	Foo2:    "foo2",
+	IntStr:  42,
+	String:  "16",
+	Map: map[string]Small{
+		"17": {Tag: "tag17"},
+		"18": {Tag: "tag18"},
+	},
+	MapP: map[string]*Small{
+		"19": &Small{Tag: "tag19"},
+		"20": nil,
+	},
+	EmptyMap:    map[string]Small{},
+	Slice:       []Small{{Tag: "tag20"}, {Tag: "tag21"}},
+	SliceP:      []*Small{&Small{Tag: "tag22"}, nil, &Small{Tag: "tag23"}},
+	EmptySlice:  []Small{},
+	StringSlice: []string{"str24", "str25", "str26"},
+	ByteSlice:   []byte{27, 28, 29},
+	Small:       Small{Tag: "tag30"},
+	PSmall:      &Small{Tag: "tag31"},
+	Interface:   5.2,
+}
+
+var pallValue = All{
+	PBool:      &allValue.Bool,
+	PInt:       &allValue.Int,
+	PInt8:      &allValue.Int8,
+	PInt16:     &allValue.Int16,
+	PInt32:     &allValue.Int32,
+	PInt64:     &allValue.Int64,
+	PUint:      &allValue.Uint,
+	PUint8:     &allValue.Uint8,
+	PUint16:    &allValue.Uint16,
+	PUint32:    &allValue.Uint32,
+	PUint64:    &allValue.Uint64,
+	PUintptr:   &allValue.Uintptr,
+	PFloat32:   &allValue.Float32,
+	PFloat64:   &allValue.Float64,
+	PString:    &allValue.String,
+	PMap:       &allValue.Map,
+	PMapP:      &allValue.MapP,
+	PSlice:     &allValue.Slice,
+	PSliceP:    &allValue.SliceP,
+	PPSmall:    &allValue.PSmall,
+	PInterface: &allValue.Interface,
+}
+
+var allValueIndent = `{
+	"Bool": true,
+	"Int": 2,
+	"Int8": 3,
+	"Int16": 4,
+	"Int32": 5,
+	"Int64": 6,
+	"Uint": 7,
+	"Uint8": 8,
+	"Uint16": 9,
+	"Uint32": 10,
+	"Uint64": 11,
+	"Uintptr": 12,
+	"Float32": 14.1,
+	"Float64": 15.1,
+	"bar": "foo",
+	"bar2": "foo2",
+	"IntStr": "42",
+	"PBool": null,
+	"PInt": null,
+	"PInt8": null,
+	"PInt16": null,
+	"PInt32": null,
+	"PInt64": null,
+	"PUint": null,
+	"PUint8": null,
+	"PUint16": null,
+	"PUint32": null,
+	"PUint64": null,
+	"PUintptr": null,
+	"PFloat32": null,
+	"PFloat64": null,
+	"String": "16",
+	"PString": null,
+	"Map": {
+		"17": {
+			"Tag": "tag17"
+		},
+		"18": {
+			"Tag": "tag18"
+		}
+	},
+	"MapP": {
+		"19": {
+			"Tag": "tag19"
+		},
+		"20": null
+	},
+	"PMap": null,
+	"PMapP": null,
+	"EmptyMap": {},
+	"NilMap": null,
+	"Slice": [
+		{
+			"Tag": "tag20"
+		},
+		{
+			"Tag": "tag21"
+		}
+	],
+	"SliceP": [
+		{
+			"Tag": "tag22"
+		},
+		null,
+		{
+			"Tag": "tag23"
+		}
+	],
+	"PSlice": null,
+	"PSliceP": null,
+	"EmptySlice": [],
+	"NilSlice": null,
+	"StringSlice": [
+		"str24",
+		"str25",
+		"str26"
+	],
+	"ByteSlice": "Gxwd",
+	"Small": {
+		"Tag": "tag30"
+	},
+	"PSmall": {
+		"Tag": "tag31"
+	},
+	"PPSmall": null,
+	"Interface": 5.2,
+	"PInterface": null
+}`
+
+var allValueCompact = strings.Map(noSpace, allValueIndent)
+
+var pallValueIndent = `{
+	"Bool": false,
+	"Int": 0,
+	"Int8": 0,
+	"Int16": 0,
+	"Int32": 0,
+	"Int64": 0,
+	"Uint": 0,
+	"Uint8": 0,
+	"Uint16": 0,
+	"Uint32": 0,
+	"Uint64": 0,
+	"Uintptr": 0,
+	"Float32": 0,
+	"Float64": 0,
+	"bar": "",
+	"bar2": "",
+        "IntStr": "0",
+	"PBool": true,
+	"PInt": 2,
+	"PInt8": 3,
+	"PInt16": 4,
+	"PInt32": 5,
+	"PInt64": 6,
+	"PUint": 7,
+	"PUint8": 8,
+	"PUint16": 9,
+	"PUint32": 10,
+	"PUint64": 11,
+	"PUintptr": 12,
+	"PFloat32": 14.1,
+	"PFloat64": 15.1,
+	"String": "",
+	"PString": "16",
+	"Map": null,
+	"MapP": null,
+	"PMap": {
+		"17": {
+			"Tag": "tag17"
+		},
+		"18": {
+			"Tag": "tag18"
+		}
+	},
+	"PMapP": {
+		"19": {
+			"Tag": "tag19"
+		},
+		"20": null
+	},
+	"EmptyMap": null,
+	"NilMap": null,
+	"Slice": null,
+	"SliceP": null,
+	"PSlice": [
+		{
+			"Tag": "tag20"
+		},
+		{
+			"Tag": "tag21"
+		}
+	],
+	"PSliceP": [
+		{
+			"Tag": "tag22"
+		},
+		null,
+		{
+			"Tag": "tag23"
+		}
+	],
+	"EmptySlice": null,
+	"NilSlice": null,
+	"StringSlice": null,
+	"ByteSlice": null,
+	"Small": {
+		"Tag": ""
+	},
+	"PSmall": null,
+	"PPSmall": {
+		"Tag": "tag31"
+	},
+	"Interface": null,
+	"PInterface": 5.2
+}`
+
+var pallValueCompact = strings.Map(noSpace, pallValueIndent)
diff --git a/libgo/go/encoding/json/encode.go b/libgo/go/encoding/json/encode.go
new file mode 100644
index 00000000000..35964c5d9c2
--- /dev/null
+++ b/libgo/go/encoding/json/encode.go
@@ -0,0 +1,472 @@
+// Copyright 2010 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package json implements encoding and decoding of JSON objects as defined in
+// RFC 4627.
+//
+// See "JSON and Go" for an introduction to this package:
+// http://blog.golang.org/2011/01/json-and-go.html
+package json
+
+import (
+	"bytes"
+	"encoding/base64"
+	"reflect"
+	"runtime"
+	"sort"
+	"strconv"
+	"unicode"
+	"unicode/utf8"
+)
+
+// Marshal returns the JSON encoding of v.
+//
+// Marshal traverses the value v recursively.
+// If an encountered value implements the Marshaler interface
+// and is not a nil pointer, Marshal calls its MarshalJSON method
+// to produce JSON.  The nil pointer exception is not strictly necessary
+// but mimics a similar, necessary exception in the behavior of
+// UnmarshalJSON.
+//
+// Otherwise, Marshal uses the following type-dependent default encodings:
+//
+// Boolean values encode as JSON booleans.
+//
+// Floating point and integer values encode as JSON numbers.
+//
+// String values encode as JSON strings, with each invalid UTF-8 sequence
+// replaced by the encoding of the Unicode replacement character U+FFFD.
+//
+// Array and slice values encode as JSON arrays, except that
+// []byte encodes as a base64-encoded string.
+//
+// Struct values encode as JSON objects. Each exported struct field
+// becomes a member of the object unless
+//   - the field's tag is "-", or
+//   - the field is empty and its tag specifies the "omitempty" option.
+// The empty values are false, 0, any
+// nil pointer or interface value, and any array, slice, map, or string of
+// length zero. The object's default key string is the struct field name
+// but can be specified in the struct field's tag value. The "json" key in
+// struct field's tag value is the key name, followed by an optional comma
+// and options. Examples:
+//
+//   // Field is ignored by this package.
+//   Field int `json:"-"`
+//
+//   // Field appears in JSON as key "myName".
+//   Field int `json:"myName"`
+//
+//   // Field appears in JSON as key "myName" and
+//   // the field is omitted from the object if its value is empty,
+//   // as defined above.
+//   Field int `json:"myName,omitempty"`
+//
+//   // Field appears in JSON as key "Field" (the default), but
+//   // the field is skipped if empty.
+//   // Note the leading comma.
+//   Field int `json:",omitempty"`
+//
+// The "string" option signals that a field is stored as JSON inside a
+// JSON-encoded string.  This extra level of encoding is sometimes
+// used when communicating with JavaScript programs:
+//
+//    Int64String int64 `json:",string"`
+//
+// The key name will be used if it's a non-empty string consisting of
+// only Unicode letters, digits, dollar signs, hyphens, and underscores.
+//
+// Map values encode as JSON objects.
+// The map's key type must be string; the object keys are used directly
+// as map keys.
+//
+// Pointer values encode as the value pointed to.
+// A nil pointer encodes as the null JSON object.
+//
+// Interface values encode as the value contained in the interface.
+// A nil interface value encodes as the null JSON object.
+//
+// Channel, complex, and function values cannot be encoded in JSON.
+// Attempting to encode such a value causes Marshal to return
+// an InvalidTypeError.
+//
+// JSON cannot represent cyclic data structures and Marshal does not
+// handle them.  Passing cyclic structures to Marshal will result in
+// an infinite recursion.
+//
+func Marshal(v interface{}) ([]byte, error) {
+	e := &encodeState{}
+	err := e.marshal(v)
+	if err != nil {
+		return nil, err
+	}
+	return e.Bytes(), nil
+}
+
+// MarshalIndent is like Marshal but applies Indent to format the output.
+func MarshalIndent(v interface{}, prefix, indent string) ([]byte, error) {
+	b, err := Marshal(v)
+	if err != nil {
+		return nil, err
+	}
+	var buf bytes.Buffer
+	err = Indent(&buf, b, prefix, indent)
+	if err != nil {
+		return nil, err
+	}
+	return buf.Bytes(), nil
+}
+
+// MarshalForHTML is like Marshal but applies HTMLEscape to the output.
+func MarshalForHTML(v interface{}) ([]byte, error) {
+	b, err := Marshal(v)
+	if err != nil {
+		return nil, err
+	}
+	var buf bytes.Buffer
+	HTMLEscape(&buf, b)
+	return buf.Bytes(), nil
+}
+
+// HTMLEscape appends to dst the JSON-encoded src with <, >, and &
+// characters inside string literals changed to \u003c, \u003e, \u0026
+// so that the JSON will be safe to embed inside HTML <script> tags.
+// For historical reasons, web browsers don't honor standard HTML
+// escaping within <script> tags, so an alternative JSON encoding must
+// be used.
+func HTMLEscape(dst *bytes.Buffer, src []byte) {
+	// < > & can only appear in string literals,
+	// so just scan the string one byte at a time.
+	start := 0
+	for i, c := range src {
+		if c == '<' || c == '>' || c == '&' {
+			if start < i {
+				dst.Write(src[start:i])
+			}
+			dst.WriteString(`\u00`)
+			dst.WriteByte(hex[c>>4])
+			dst.WriteByte(hex[c&0xF])
+			start = i + 1
+		}
+	}
+	if start < len(src) {
+		dst.Write(src[start:])
+	}
+}
+
+// Marshaler is the interface implemented by objects that
+// can marshal themselves into valid JSON.
+type Marshaler interface {
+	MarshalJSON() ([]byte, error)
+}
+
+type UnsupportedTypeError struct {
+	Type reflect.Type
+}
+
+func (e *UnsupportedTypeError) Error() string {
+	return "json: unsupported type: " + e.Type.String()
+}
+
+type InvalidUTF8Error struct {
+	S string
+}
+
+func (e *InvalidUTF8Error) Error() string {
+	return "json: invalid UTF-8 in string: " + strconv.Quote(e.S)
+}
+
+type MarshalerError struct {
+	Type reflect.Type
+	Err  error
+}
+
+func (e *MarshalerError) Error() string {
+	return "json: error calling MarshalJSON for type " + e.Type.String() + ": " + e.Err.Error()
+}
+
+type interfaceOrPtrValue interface {
+	IsNil() bool
+	Elem() reflect.Value
+}
+
+var hex = "0123456789abcdef"
+
+// An encodeState encodes JSON into a bytes.Buffer.
+type encodeState struct {
+	bytes.Buffer // accumulated output
+}
+
+func (e *encodeState) marshal(v interface{}) (err error) {
+	defer func() {
+		if r := recover(); r != nil {
+			if _, ok := r.(runtime.Error); ok {
+				panic(r)
+			}
+			err = r.(error)
+		}
+	}()
+	e.reflectValue(reflect.ValueOf(v))
+	return nil
+}
+
+func (e *encodeState) error(err error) {
+	panic(err)
+}
+
+var byteSliceType = reflect.TypeOf([]byte(nil))
+
+func isEmptyValue(v reflect.Value) bool {
+	switch v.Kind() {
+	case reflect.Array, reflect.Map, reflect.Slice, reflect.String:
+		return v.Len() == 0
+	case reflect.Bool:
+		return !v.Bool()
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		return v.Int() == 0
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+		return v.Uint() == 0
+	case reflect.Float32, reflect.Float64:
+		return v.Float() == 0
+	case reflect.Interface, reflect.Ptr:
+		return v.IsNil()
+	}
+	return false
+}
+
+func (e *encodeState) reflectValue(v reflect.Value) {
+	e.reflectValueQuoted(v, false)
+}
+
+// reflectValueQuoted writes the value in v to the output.
+// If quoted is true, the serialization is wrapped in a JSON string.
+func (e *encodeState) reflectValueQuoted(v reflect.Value, quoted bool) {
+	if !v.IsValid() {
+		e.WriteString("null")
+		return
+	}
+
+	if j, ok := v.Interface().(Marshaler); ok && (v.Kind() != reflect.Ptr || !v.IsNil()) {
+		b, err := j.MarshalJSON()
+		if err == nil {
+			// copy JSON into buffer, checking validity.
+			err = Compact(&e.Buffer, b)
+		}
+		if err != nil {
+			e.error(&MarshalerError{v.Type(), err})
+		}
+		return
+	}
+
+	writeString := (*encodeState).WriteString
+	if quoted {
+		writeString = (*encodeState).string
+	}
+
+	switch v.Kind() {
+	case reflect.Bool:
+		x := v.Bool()
+		if x {
+			writeString(e, "true")
+		} else {
+			writeString(e, "false")
+		}
+
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		writeString(e, strconv.Itoa64(v.Int()))
+
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+		writeString(e, strconv.Uitoa64(v.Uint()))
+
+	case reflect.Float32, reflect.Float64:
+		writeString(e, strconv.FtoaN(v.Float(), 'g', -1, v.Type().Bits()))
+
+	case reflect.String:
+		if quoted {
+			sb, err := Marshal(v.String())
+			if err != nil {
+				e.error(err)
+			}
+			e.string(string(sb))
+		} else {
+			e.string(v.String())
+		}
+
+	case reflect.Struct:
+		e.WriteByte('{')
+		t := v.Type()
+		n := v.NumField()
+		first := true
+		for i := 0; i < n; i++ {
+			f := t.Field(i)
+			if f.PkgPath != "" {
+				continue
+			}
+			tag, omitEmpty, quoted := f.Name, false, false
+			if tv := f.Tag.Get("json"); tv != "" {
+				if tv == "-" {
+					continue
+				}
+				name, opts := parseTag(tv)
+				if isValidTag(name) {
+					tag = name
+				}
+				omitEmpty = opts.Contains("omitempty")
+				quoted = opts.Contains("string")
+			}
+			fieldValue := v.Field(i)
+			if omitEmpty && isEmptyValue(fieldValue) {
+				continue
+			}
+			if first {
+				first = false
+			} else {
+				e.WriteByte(',')
+			}
+			e.string(tag)
+			e.WriteByte(':')
+			e.reflectValueQuoted(fieldValue, quoted)
+		}
+		e.WriteByte('}')
+
+	case reflect.Map:
+		if v.Type().Key().Kind() != reflect.String {
+			e.error(&UnsupportedTypeError{v.Type()})
+		}
+		if v.IsNil() {
+			e.WriteString("null")
+			break
+		}
+		e.WriteByte('{')
+		var sv stringValues = v.MapKeys()
+		sort.Sort(sv)
+		for i, k := range sv {
+			if i > 0 {
+				e.WriteByte(',')
+			}
+			e.string(k.String())
+			e.WriteByte(':')
+			e.reflectValue(v.MapIndex(k))
+		}
+		e.WriteByte('}')
+
+	case reflect.Slice:
+		if v.IsNil() {
+			e.WriteString("null")
+			break
+		}
+		// Slices can be marshalled as nil, but otherwise are handled
+		// as arrays.
+		fallthrough
+	case reflect.Array:
+		if v.Type() == byteSliceType {
+			e.WriteByte('"')
+			s := v.Interface().([]byte)
+			if len(s) < 1024 {
+				// for small buffers, using Encode directly is much faster.
+				dst := make([]byte, base64.StdEncoding.EncodedLen(len(s)))
+				base64.StdEncoding.Encode(dst, s)
+				e.Write(dst)
+			} else {
+				// for large buffers, avoid unnecessary extra temporary
+				// buffer space.
+				enc := base64.NewEncoder(base64.StdEncoding, e)
+				enc.Write(s)
+				enc.Close()
+			}
+			e.WriteByte('"')
+			break
+		}
+		e.WriteByte('[')
+		n := v.Len()
+		for i := 0; i < n; i++ {
+			if i > 0 {
+				e.WriteByte(',')
+			}
+			e.reflectValue(v.Index(i))
+		}
+		e.WriteByte(']')
+
+	case reflect.Interface, reflect.Ptr:
+		if v.IsNil() {
+			e.WriteString("null")
+			return
+		}
+		e.reflectValue(v.Elem())
+
+	default:
+		e.error(&UnsupportedTypeError{v.Type()})
+	}
+	return
+}
+
+func isValidTag(s string) bool {
+	if s == "" {
+		return false
+	}
+	for _, c := range s {
+		if c != '$' && c != '-' && c != '_' && !unicode.IsLetter(c) && !unicode.IsDigit(c) {
+			return false
+		}
+	}
+	return true
+}
+
+// stringValues is a slice of reflect.Value holding *reflect.StringValue.
+// It implements the methods to sort by string.
+type stringValues []reflect.Value
+
+func (sv stringValues) Len() int           { return len(sv) }
+func (sv stringValues) Swap(i, j int)      { sv[i], sv[j] = sv[j], sv[i] }
+func (sv stringValues) Less(i, j int) bool { return sv.get(i) < sv.get(j) }
+func (sv stringValues) get(i int) string   { return sv[i].String() }
+
+func (e *encodeState) string(s string) (int, error) {
+	len0 := e.Len()
+	e.WriteByte('"')
+	start := 0
+	for i := 0; i < len(s); {
+		if b := s[i]; b < utf8.RuneSelf {
+			if 0x20 <= b && b != '\\' && b != '"' && b != '<' && b != '>' {
+				i++
+				continue
+			}
+			if start < i {
+				e.WriteString(s[start:i])
+			}
+			switch b {
+			case '\\', '"':
+				e.WriteByte('\\')
+				e.WriteByte(b)
+			case '\n':
+				e.WriteByte('\\')
+				e.WriteByte('n')
+			case '\r':
+				e.WriteByte('\\')
+				e.WriteByte('r')
+			default:
+				// This encodes bytes < 0x20 except for \n and \r,
+				// as well as < and >. The latter are escaped because they
+				// can lead to security holes when user-controlled strings
+				// are rendered into JSON and served to some browsers.
+				e.WriteString(`\u00`)
+				e.WriteByte(hex[b>>4])
+				e.WriteByte(hex[b&0xF])
+			}
+			i++
+			start = i
+			continue
+		}
+		c, size := utf8.DecodeRuneInString(s[i:])
+		if c == utf8.RuneError && size == 1 {
+			e.error(&InvalidUTF8Error{s})
+		}
+		i += size
+	}
+	if start < len(s) {
+		e.WriteString(s[start:])
+	}
+	e.WriteByte('"')
+	return e.Len() - len0, nil
+}
diff --git a/libgo/go/encoding/json/encode_test.go b/libgo/go/encoding/json/encode_test.go
new file mode 100644
index 00000000000..92f266aba63
--- /dev/null
+++ b/libgo/go/encoding/json/encode_test.go
@@ -0,0 +1,84 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package json
+
+import (
+	"bytes"
+	"reflect"
+	"testing"
+)
+
+type Optionals struct {
+	Sr string `json:"sr"`
+	So string `json:"so,omitempty"`
+	Sw string `json:"-"`
+
+	Ir int `json:"omitempty"` // actually named omitempty, not an option
+	Io int `json:"io,omitempty"`
+
+	Slr []string `json:"slr,random"`
+	Slo []string `json:"slo,omitempty"`
+
+	Mr map[string]interface{} `json:"mr"`
+	Mo map[string]interface{} `json:",omitempty"`
+}
+
+var optionalsExpected = `{
+ "sr": "",
+ "omitempty": 0,
+ "slr": null,
+ "mr": {}
+}`
+
+func TestOmitEmpty(t *testing.T) {
+	var o Optionals
+	o.Sw = "something"
+	o.Mr = map[string]interface{}{}
+	o.Mo = map[string]interface{}{}
+
+	got, err := MarshalIndent(&o, "", " ")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got := string(got); got != optionalsExpected {
+		t.Errorf(" got: %s\nwant: %s\n", got, optionalsExpected)
+	}
+}
+
+type StringTag struct {
+	BoolStr bool   `json:",string"`
+	IntStr  int64  `json:",string"`
+	StrStr  string `json:",string"`
+}
+
+var stringTagExpected = `{
+ "BoolStr": "true",
+ "IntStr": "42",
+ "StrStr": "\"xzbit\""
+}`
+
+func TestStringTag(t *testing.T) {
+	var s StringTag
+	s.BoolStr = true
+	s.IntStr = 42
+	s.StrStr = "xzbit"
+	got, err := MarshalIndent(&s, "", " ")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got := string(got); got != stringTagExpected {
+		t.Fatalf(" got: %s\nwant: %s\n", got, stringTagExpected)
+	}
+
+	// Verify that it round-trips.
+	var s2 StringTag
+	err = NewDecoder(bytes.NewBuffer(got)).Decode(&s2)
+	if err != nil {
+		t.Fatalf("Decode: %v", err)
+	}
+	if !reflect.DeepEqual(s, s2) {
+		t.Fatalf("decode didn't match.\nsource: %#v\nEncoded as:\n%s\ndecode: %#v", s, string(got), s2)
+	}
+}
diff --git a/libgo/go/encoding/json/indent.go b/libgo/go/encoding/json/indent.go
new file mode 100644
index 00000000000..5ba19b07ac6
--- /dev/null
+++ b/libgo/go/encoding/json/indent.go
@@ -0,0 +1,114 @@
+// Copyright 2010 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package json
+
+import "bytes"
+
+// Compact appends to dst the JSON-encoded src with
+// insignificant space characters elided.
+func Compact(dst *bytes.Buffer, src []byte) error {
+	origLen := dst.Len()
+	var scan scanner
+	scan.reset()
+	start := 0
+	for i, c := range src {
+		v := scan.step(&scan, int(c))
+		if v >= scanSkipSpace {
+			if v == scanError {
+				break
+			}
+			if start < i {
+				dst.Write(src[start:i])
+			}
+			start = i + 1
+		}
+	}
+	if scan.eof() == scanError {
+		dst.Truncate(origLen)
+		return scan.err
+	}
+	if start < len(src) {
+		dst.Write(src[start:])
+	}
+	return nil
+}
+
+func newline(dst *bytes.Buffer, prefix, indent string, depth int) {
+	dst.WriteByte('\n')
+	dst.WriteString(prefix)
+	for i := 0; i < depth; i++ {
+		dst.WriteString(indent)
+	}
+}
+
+// Indent appends to dst an indented form of the JSON-encoded src.
+// Each element in a JSON object or array begins on a new,
+// indented line beginning with prefix followed by one or more
+// copies of indent according to the indentation nesting.
+// The data appended to dst has no trailing newline, to make it easier
+// to embed inside other formatted JSON data.
+func Indent(dst *bytes.Buffer, src []byte, prefix, indent string) error {
+	origLen := dst.Len()
+	var scan scanner
+	scan.reset()
+	needIndent := false
+	depth := 0
+	for _, c := range src {
+		scan.bytes++
+		v := scan.step(&scan, int(c))
+		if v == scanSkipSpace {
+			continue
+		}
+		if v == scanError {
+			break
+		}
+		if needIndent && v != scanEndObject && v != scanEndArray {
+			needIndent = false
+			depth++
+			newline(dst, prefix, indent, depth)
+		}
+
+		// Emit semantically uninteresting bytes
+		// (in particular, punctuation in strings) unmodified.
+		if v == scanContinue {
+			dst.WriteByte(c)
+			continue
+		}
+
+		// Add spacing around real punctuation.
+		switch c {
+		case '{', '[':
+			// delay indent so that empty object and array are formatted as {} and [].
+			needIndent = true
+			dst.WriteByte(c)
+
+		case ',':
+			dst.WriteByte(c)
+			newline(dst, prefix, indent, depth)
+
+		case ':':
+			dst.WriteByte(c)
+			dst.WriteByte(' ')
+
+		case '}', ']':
+			if needIndent {
+				// suppress indent in empty object/array
+				needIndent = false
+			} else {
+				depth--
+				newline(dst, prefix, indent, depth)
+			}
+			dst.WriteByte(c)
+
+		default:
+			dst.WriteByte(c)
+		}
+	}
+	if scan.eof() == scanError {
+		dst.Truncate(origLen)
+		return scan.err
+	}
+	return nil
+}
diff --git a/libgo/go/encoding/json/scanner.go b/libgo/go/encoding/json/scanner.go
new file mode 100644
index 00000000000..179690464b9
--- /dev/null
+++ b/libgo/go/encoding/json/scanner.go
@@ -0,0 +1,621 @@
+// Copyright 2010 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package json
+
+// JSON value parser state machine.
+// Just about at the limit of what is reasonable to write by hand.
+// Some parts are a bit tedious, but overall it nicely factors out the
+// otherwise common code from the multiple scanning functions
+// in this package (Compact, Indent, checkValid, nextValue, etc).
+//
+// This file starts with two simple examples using the scanner
+// before diving into the scanner itself.
+
+import "strconv"
+
+// checkValid verifies that data is valid JSON-encoded data.
+// scan is passed in for use by checkValid to avoid an allocation.
+func checkValid(data []byte, scan *scanner) error {
+	scan.reset()
+	for _, c := range data {
+		scan.bytes++
+		if scan.step(scan, int(c)) == scanError {
+			return scan.err
+		}
+	}
+	if scan.eof() == scanError {
+		return scan.err
+	}
+	return nil
+}
+
+// nextValue splits data after the next whole JSON value,
+// returning that value and the bytes that follow it as separate slices.
+// scan is passed in for use by nextValue to avoid an allocation.
+func nextValue(data []byte, scan *scanner) (value, rest []byte, err error) {
+	scan.reset()
+	for i, c := range data {
+		v := scan.step(scan, int(c))
+		if v >= scanEnd {
+			switch v {
+			case scanError:
+				return nil, nil, scan.err
+			case scanEnd:
+				return data[0:i], data[i:], nil
+			}
+		}
+	}
+	if scan.eof() == scanError {
+		return nil, nil, scan.err
+	}
+	return data, nil, nil
+}
+
+// A SyntaxError is a description of a JSON syntax error.
+type SyntaxError struct {
+	msg    string // description of error
+	Offset int64  // error occurred after reading Offset bytes
+}
+
+func (e *SyntaxError) Error() string { return e.msg }
+
+// A scanner is a JSON scanning state machine.
+// Callers call scan.reset() and then pass bytes in one at a time
+// by calling scan.step(&scan, c) for each byte.
+// The return value, referred to as an opcode, tells the
+// caller about significant parsing events like beginning
+// and ending literals, objects, and arrays, so that the
+// caller can follow along if it wishes.
+// The return value scanEnd indicates that a single top-level
+// JSON value has been completed, *before* the byte that
+// just got passed in.  (The indication must be delayed in order
+// to recognize the end of numbers: is 123 a whole value or
+// the beginning of 12345e+6?).
+type scanner struct {
+	// The step is a func to be called to execute the next transition.
+	// Also tried using an integer constant and a single func
+	// with a switch, but using the func directly was 10% faster
+	// on a 64-bit Mac Mini, and it's nicer to read.
+	step func(*scanner, int) int
+
+	// Stack of what we're in the middle of - array values, object keys, object values.
+	parseState []int
+
+	// Error that happened, if any.
+	err error
+
+	// 1-byte redo (see undo method)
+	redoCode  int
+	redoState func(*scanner, int) int
+
+	// total bytes consumed, updated by decoder.Decode
+	bytes int64
+}
+
+// These values are returned by the state transition functions
+// assigned to scanner.state and the method scanner.eof.
+// They give details about the current state of the scan that
+// callers might be interested to know about.
+// It is okay to ignore the return value of any particular
+// call to scanner.state: if one call returns scanError,
+// every subsequent call will return scanError too.
+const (
+	// Continue.
+	scanContinue     = iota // uninteresting byte
+	scanBeginLiteral        // end implied by next result != scanContinue
+	scanBeginObject         // begin object
+	scanObjectKey           // just finished object key (string)
+	scanObjectValue         // just finished non-last object value
+	scanEndObject           // end object (implies scanObjectValue if possible)
+	scanBeginArray          // begin array
+	scanArrayValue          // just finished array value
+	scanEndArray            // end array (implies scanArrayValue if possible)
+	scanSkipSpace           // space byte; can skip; known to be last "continue" result
+
+	// Stop.
+	scanEnd   // top-level value ended *before* this byte; known to be first "stop" result
+	scanError // hit an error, scanner.err.
+)
+
+// These values are stored in the parseState stack.
+// They give the current state of a composite value
+// being scanned.  If the parser is inside a nested value
+// the parseState describes the nested state, outermost at entry 0.
+const (
+	parseObjectKey   = iota // parsing object key (before colon)
+	parseObjectValue        // parsing object value (after colon)
+	parseArrayValue         // parsing array value
+)
+
+// reset prepares the scanner for use.
+// It must be called before calling s.step.
+func (s *scanner) reset() {
+	s.step = stateBeginValue
+	s.parseState = s.parseState[0:0]
+	s.err = nil
+}
+
+// eof tells the scanner that the end of input has been reached.
+// It returns a scan status just as s.step does.
+func (s *scanner) eof() int {
+	if s.err != nil {
+		return scanError
+	}
+	if s.step == stateEndTop {
+		return scanEnd
+	}
+	s.step(s, ' ')
+	if s.step == stateEndTop {
+		return scanEnd
+	}
+	if s.err == nil {
+		s.err = &SyntaxError{"unexpected end of JSON input", s.bytes}
+	}
+	return scanError
+}
+
+// pushParseState pushes a new parse state p onto the parse stack.
+func (s *scanner) pushParseState(p int) {
+	s.parseState = append(s.parseState, p)
+}
+
+// popParseState pops a parse state (already obtained) off the stack
+// and updates s.step accordingly.
+func (s *scanner) popParseState() {
+	n := len(s.parseState) - 1
+	s.parseState = s.parseState[0:n]
+	if n == 0 {
+		s.step = stateEndTop
+	} else {
+		s.step = stateEndValue
+	}
+}
+
+func isSpace(c rune) bool {
+	return c == ' ' || c == '\t' || c == '\r' || c == '\n'
+}
+
+// NOTE(rsc): The various instances of
+//
+//	if c <= ' ' && (c == ' ' || c == '\t' || c == '\r' || c == '\n')
+//
+// below should all be if c <= ' ' && isSpace(c), but inlining
+// the checks makes a significant difference (>10%) in tight loops
+// such as nextValue.  These should be rewritten with the clearer
+// function call once 6g knows to inline the call.
+
+// stateBeginValueOrEmpty is the state after reading `[`.
+func stateBeginValueOrEmpty(s *scanner, c int) int {
+	if c <= ' ' && (c == ' ' || c == '\t' || c == '\r' || c == '\n') {
+		return scanSkipSpace
+	}
+	if c == ']' {
+		return stateEndValue(s, c)
+	}
+	return stateBeginValue(s, c)
+}
+
+// stateBeginValue is the state at the beginning of the input.
+func stateBeginValue(s *scanner, c int) int {
+	if c <= ' ' && (c == ' ' || c == '\t' || c == '\r' || c == '\n') {
+		return scanSkipSpace
+	}
+	switch c {
+	case '{':
+		s.step = stateBeginStringOrEmpty
+		s.pushParseState(parseObjectKey)
+		return scanBeginObject
+	case '[':
+		s.step = stateBeginValueOrEmpty
+		s.pushParseState(parseArrayValue)
+		return scanBeginArray
+	case '"':
+		s.step = stateInString
+		return scanBeginLiteral
+	case '-':
+		s.step = stateNeg
+		return scanBeginLiteral
+	case '0': // beginning of 0.123
+		s.step = state0
+		return scanBeginLiteral
+	case 't': // beginning of true
+		s.step = stateT
+		return scanBeginLiteral
+	case 'f': // beginning of false
+		s.step = stateF
+		return scanBeginLiteral
+	case 'n': // beginning of null
+		s.step = stateN
+		return scanBeginLiteral
+	}
+	if '1' <= c && c <= '9' { // beginning of 1234.5
+		s.step = state1
+		return scanBeginLiteral
+	}
+	return s.error(c, "looking for beginning of value")
+}
+
+// stateBeginStringOrEmpty is the state after reading `{`.
+func stateBeginStringOrEmpty(s *scanner, c int) int {
+	if c <= ' ' && (c == ' ' || c == '\t' || c == '\r' || c == '\n') {
+		return scanSkipSpace
+	}
+	if c == '}' {
+		n := len(s.parseState)
+		s.parseState[n-1] = parseObjectValue
+		return stateEndValue(s, c)
+	}
+	return stateBeginString(s, c)
+}
+
+// stateBeginString is the state after reading `{"key": value,`.
+func stateBeginString(s *scanner, c int) int {
+	if c <= ' ' && (c == ' ' || c == '\t' || c == '\r' || c == '\n') {
+		return scanSkipSpace
+	}
+	if c == '"' {
+		s.step = stateInString
+		return scanBeginLiteral
+	}
+	return s.error(c, "looking for beginning of object key string")
+}
+
+// stateEndValue is the state after completing a value,
+// such as after reading `{}` or `true` or `["x"`.
+func stateEndValue(s *scanner, c int) int {
+	n := len(s.parseState)
+	if n == 0 {
+		// Completed top-level before the current byte.
+		s.step = stateEndTop
+		return stateEndTop(s, c)
+	}
+	if c <= ' ' && (c == ' ' || c == '\t' || c == '\r' || c == '\n') {
+		s.step = stateEndValue
+		return scanSkipSpace
+	}
+	ps := s.parseState[n-1]
+	switch ps {
+	case parseObjectKey:
+		if c == ':' {
+			s.parseState[n-1] = parseObjectValue
+			s.step = stateBeginValue
+			return scanObjectKey
+		}
+		return s.error(c, "after object key")
+	case parseObjectValue:
+		if c == ',' {
+			s.parseState[n-1] = parseObjectKey
+			s.step = stateBeginString
+			return scanObjectValue
+		}
+		if c == '}' {
+			s.popParseState()
+			return scanEndObject
+		}
+		return s.error(c, "after object key:value pair")
+	case parseArrayValue:
+		if c == ',' {
+			s.step = stateBeginValue
+			return scanArrayValue
+		}
+		if c == ']' {
+			s.popParseState()
+			return scanEndArray
+		}
+		return s.error(c, "after array element")
+	}
+	return s.error(c, "")
+}
+
+// stateEndTop is the state after finishing the top-level value,
+// such as after reading `{}` or `[1,2,3]`.
+// Only space characters should be seen now.
+func stateEndTop(s *scanner, c int) int {
+	if c != ' ' && c != '\t' && c != '\r' && c != '\n' {
+		// Complain about non-space byte on next call.
+		s.error(c, "after top-level value")
+	}
+	return scanEnd
+}
+
+// stateInString is the state after reading `"`.
+func stateInString(s *scanner, c int) int {
+	if c == '"' {
+		s.step = stateEndValue
+		return scanContinue
+	}
+	if c == '\\' {
+		s.step = stateInStringEsc
+		return scanContinue
+	}
+	if c < 0x20 {
+		return s.error(c, "in string literal")
+	}
+	return scanContinue
+}
+
+// stateInStringEsc is the state after reading `"\` during a quoted string.
+func stateInStringEsc(s *scanner, c int) int {
+	switch c {
+	case 'b', 'f', 'n', 'r', 't', '\\', '/', '"':
+		s.step = stateInString
+		return scanContinue
+	}
+	if c == 'u' {
+		s.step = stateInStringEscU
+		return scanContinue
+	}
+	return s.error(c, "in string escape code")
+}
+
+// stateInStringEscU is the state after reading `"\u` during a quoted string.
+func stateInStringEscU(s *scanner, c int) int {
+	if '0' <= c && c <= '9' || 'a' <= c && c <= 'f' || 'A' <= c && c <= 'F' {
+		s.step = stateInStringEscU1
+		return scanContinue
+	}
+	// numbers
+	return s.error(c, "in \\u hexadecimal character escape")
+}
+
+// stateInStringEscU1 is the state after reading `"\u1` during a quoted string.
+func stateInStringEscU1(s *scanner, c int) int {
+	if '0' <= c && c <= '9' || 'a' <= c && c <= 'f' || 'A' <= c && c <= 'F' {
+		s.step = stateInStringEscU12
+		return scanContinue
+	}
+	// numbers
+	return s.error(c, "in \\u hexadecimal character escape")
+}
+
+// stateInStringEscU12 is the state after reading `"\u12` during a quoted string.
+func stateInStringEscU12(s *scanner, c int) int {
+	if '0' <= c && c <= '9' || 'a' <= c && c <= 'f' || 'A' <= c && c <= 'F' {
+		s.step = stateInStringEscU123
+		return scanContinue
+	}
+	// numbers
+	return s.error(c, "in \\u hexadecimal character escape")
+}
+
+// stateInStringEscU123 is the state after reading `"\u123` during a quoted string.
+func stateInStringEscU123(s *scanner, c int) int {
+	if '0' <= c && c <= '9' || 'a' <= c && c <= 'f' || 'A' <= c && c <= 'F' {
+		s.step = stateInString
+		return scanContinue
+	}
+	// numbers
+	return s.error(c, "in \\u hexadecimal character escape")
+}
+
+// stateInStringEscU123 is the state after reading `-` during a number.
+func stateNeg(s *scanner, c int) int {
+	if c == '0' {
+		s.step = state0
+		return scanContinue
+	}
+	if '1' <= c && c <= '9' {
+		s.step = state1
+		return scanContinue
+	}
+	return s.error(c, "in numeric literal")
+}
+
+// state1 is the state after reading a non-zero integer during a number,
+// such as after reading `1` or `100` but not `0`.
+func state1(s *scanner, c int) int {
+	if '0' <= c && c <= '9' {
+		s.step = state1
+		return scanContinue
+	}
+	return state0(s, c)
+}
+
+// state0 is the state after reading `0` during a number.
+func state0(s *scanner, c int) int {
+	if c == '.' {
+		s.step = stateDot
+		return scanContinue
+	}
+	if c == 'e' || c == 'E' {
+		s.step = stateE
+		return scanContinue
+	}
+	return stateEndValue(s, c)
+}
+
+// stateDot is the state after reading the integer and decimal point in a number,
+// such as after reading `1.`.
+func stateDot(s *scanner, c int) int {
+	if '0' <= c && c <= '9' {
+		s.step = stateDot0
+		return scanContinue
+	}
+	return s.error(c, "after decimal point in numeric literal")
+}
+
+// stateDot0 is the state after reading the integer, decimal point, and subsequent
+// digits of a number, such as after reading `3.14`.
+func stateDot0(s *scanner, c int) int {
+	if '0' <= c && c <= '9' {
+		s.step = stateDot0
+		return scanContinue
+	}
+	if c == 'e' || c == 'E' {
+		s.step = stateE
+		return scanContinue
+	}
+	return stateEndValue(s, c)
+}
+
+// stateE is the state after reading the mantissa and e in a number,
+// such as after reading `314e` or `0.314e`.
+func stateE(s *scanner, c int) int {
+	if c == '+' {
+		s.step = stateESign
+		return scanContinue
+	}
+	if c == '-' {
+		s.step = stateESign
+		return scanContinue
+	}
+	return stateESign(s, c)
+}
+
+// stateESign is the state after reading the mantissa, e, and sign in a number,
+// such as after reading `314e-` or `0.314e+`.
+func stateESign(s *scanner, c int) int {
+	if '0' <= c && c <= '9' {
+		s.step = stateE0
+		return scanContinue
+	}
+	return s.error(c, "in exponent of numeric literal")
+}
+
+// stateE0 is the state after reading the mantissa, e, optional sign,
+// and at least one digit of the exponent in a number,
+// such as after reading `314e-2` or `0.314e+1` or `3.14e0`.
+func stateE0(s *scanner, c int) int {
+	if '0' <= c && c <= '9' {
+		s.step = stateE0
+		return scanContinue
+	}
+	return stateEndValue(s, c)
+}
+
+// stateT is the state after reading `t`.
+func stateT(s *scanner, c int) int {
+	if c == 'r' {
+		s.step = stateTr
+		return scanContinue
+	}
+	return s.error(c, "in literal true (expecting 'r')")
+}
+
+// stateTr is the state after reading `tr`.
+func stateTr(s *scanner, c int) int {
+	if c == 'u' {
+		s.step = stateTru
+		return scanContinue
+	}
+	return s.error(c, "in literal true (expecting 'u')")
+}
+
+// stateTru is the state after reading `tru`.
+func stateTru(s *scanner, c int) int {
+	if c == 'e' {
+		s.step = stateEndValue
+		return scanContinue
+	}
+	return s.error(c, "in literal true (expecting 'e')")
+}
+
+// stateF is the state after reading `f`.
+func stateF(s *scanner, c int) int {
+	if c == 'a' {
+		s.step = stateFa
+		return scanContinue
+	}
+	return s.error(c, "in literal false (expecting 'a')")
+}
+
+// stateFa is the state after reading `fa`.
+func stateFa(s *scanner, c int) int {
+	if c == 'l' {
+		s.step = stateFal
+		return scanContinue
+	}
+	return s.error(c, "in literal false (expecting 'l')")
+}
+
+// stateFal is the state after reading `fal`.
+func stateFal(s *scanner, c int) int {
+	if c == 's' {
+		s.step = stateFals
+		return scanContinue
+	}
+	return s.error(c, "in literal false (expecting 's')")
+}
+
+// stateFals is the state after reading `fals`.
+func stateFals(s *scanner, c int) int {
+	if c == 'e' {
+		s.step = stateEndValue
+		return scanContinue
+	}
+	return s.error(c, "in literal false (expecting 'e')")
+}
+
+// stateN is the state after reading `n`.
+func stateN(s *scanner, c int) int {
+	if c == 'u' {
+		s.step = stateNu
+		return scanContinue
+	}
+	return s.error(c, "in literal null (expecting 'u')")
+}
+
+// stateNu is the state after reading `nu`.
+func stateNu(s *scanner, c int) int {
+	if c == 'l' {
+		s.step = stateNul
+		return scanContinue
+	}
+	return s.error(c, "in literal null (expecting 'l')")
+}
+
+// stateNul is the state after reading `nul`.
+func stateNul(s *scanner, c int) int {
+	if c == 'l' {
+		s.step = stateEndValue
+		return scanContinue
+	}
+	return s.error(c, "in literal null (expecting 'l')")
+}
+
+// stateError is the state after reaching a syntax error,
+// such as after reading `[1}` or `5.1.2`.
+func stateError(s *scanner, c int) int {
+	return scanError
+}
+
+// error records an error and switches to the error state.
+func (s *scanner) error(c int, context string) int {
+	s.step = stateError
+	s.err = &SyntaxError{"invalid character " + quoteChar(c) + " " + context, s.bytes}
+	return scanError
+}
+
+// quoteChar formats c as a quoted character literal
+func quoteChar(c int) string {
+	// special cases - different from quoted strings
+	if c == '\'' {
+		return `'\''`
+	}
+	if c == '"' {
+		return `'"'`
+	}
+
+	// use quoted string with different quotation marks
+	s := strconv.Quote(string(c))
+	return "'" + s[1:len(s)-1] + "'"
+}
+
+// undo causes the scanner to return scanCode from the next state transition.
+// This gives callers a simple 1-byte undo mechanism.
+func (s *scanner) undo(scanCode int) {
+	if s.step == stateRedo {
+		panic("invalid use of scanner")
+	}
+	s.redoCode = scanCode
+	s.redoState = s.step
+	s.step = stateRedo
+}
+
+// stateRedo helps implement the scanner's 1-byte undo.
+func stateRedo(s *scanner, c int) int {
+	s.step = s.redoState
+	return s.redoCode
+}
diff --git a/libgo/go/encoding/json/scanner_test.go b/libgo/go/encoding/json/scanner_test.go
new file mode 100644
index 00000000000..a0a5995af8f
--- /dev/null
+++ b/libgo/go/encoding/json/scanner_test.go
@@ -0,0 +1,302 @@
+// Copyright 2010 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package json
+
+import (
+	"bytes"
+	"math"
+	"math/rand"
+	"reflect"
+	"testing"
+)
+
+// Tests of simple examples.
+
+type example struct {
+	compact string
+	indent  string
+}
+
+var examples = []example{
+	{`1`, `1`},
+	{`{}`, `{}`},
+	{`[]`, `[]`},
+	{`{"":2}`, "{\n\t\"\": 2\n}"},
+	{`[3]`, "[\n\t3\n]"},
+	{`[1,2,3]`, "[\n\t1,\n\t2,\n\t3\n]"},
+	{`{"x":1}`, "{\n\t\"x\": 1\n}"},
+	{ex1, ex1i},
+}
+
+var ex1 = `[true,false,null,"x",1,1.5,0,-5e+2]`
+
+var ex1i = `[
+	true,
+	false,
+	null,
+	"x",
+	1,
+	1.5,
+	0,
+	-5e+2
+]`
+
+func TestCompact(t *testing.T) {
+	var buf bytes.Buffer
+	for _, tt := range examples {
+		buf.Reset()
+		if err := Compact(&buf, []byte(tt.compact)); err != nil {
+			t.Errorf("Compact(%#q): %v", tt.compact, err)
+		} else if s := buf.String(); s != tt.compact {
+			t.Errorf("Compact(%#q) = %#q, want original", tt.compact, s)
+		}
+
+		buf.Reset()
+		if err := Compact(&buf, []byte(tt.indent)); err != nil {
+			t.Errorf("Compact(%#q): %v", tt.indent, err)
+			continue
+		} else if s := buf.String(); s != tt.compact {
+			t.Errorf("Compact(%#q) = %#q, want %#q", tt.indent, s, tt.compact)
+		}
+	}
+}
+
+func TestIndent(t *testing.T) {
+	var buf bytes.Buffer
+	for _, tt := range examples {
+		buf.Reset()
+		if err := Indent(&buf, []byte(tt.indent), "", "\t"); err != nil {
+			t.Errorf("Indent(%#q): %v", tt.indent, err)
+		} else if s := buf.String(); s != tt.indent {
+			t.Errorf("Indent(%#q) = %#q, want original", tt.indent, s)
+		}
+
+		buf.Reset()
+		if err := Indent(&buf, []byte(tt.compact), "", "\t"); err != nil {
+			t.Errorf("Indent(%#q): %v", tt.compact, err)
+			continue
+		} else if s := buf.String(); s != tt.indent {
+			t.Errorf("Indent(%#q) = %#q, want %#q", tt.compact, s, tt.indent)
+		}
+	}
+}
+
+// Tests of a large random structure.
+
+func TestCompactBig(t *testing.T) {
+	initBig()
+	var buf bytes.Buffer
+	if err := Compact(&buf, jsonBig); err != nil {
+		t.Fatalf("Compact: %v", err)
+	}
+	b := buf.Bytes()
+	if bytes.Compare(b, jsonBig) != 0 {
+		t.Error("Compact(jsonBig) != jsonBig")
+		diff(t, b, jsonBig)
+		return
+	}
+}
+
+func TestIndentBig(t *testing.T) {
+	initBig()
+	var buf bytes.Buffer
+	if err := Indent(&buf, jsonBig, "", "\t"); err != nil {
+		t.Fatalf("Indent1: %v", err)
+	}
+	b := buf.Bytes()
+	if len(b) == len(jsonBig) {
+		// jsonBig is compact (no unnecessary spaces);
+		// indenting should make it bigger
+		t.Fatalf("Indent(jsonBig) did not get bigger")
+	}
+
+	// should be idempotent
+	var buf1 bytes.Buffer
+	if err := Indent(&buf1, b, "", "\t"); err != nil {
+		t.Fatalf("Indent2: %v", err)
+	}
+	b1 := buf1.Bytes()
+	if bytes.Compare(b1, b) != 0 {
+		t.Error("Indent(Indent(jsonBig)) != Indent(jsonBig)")
+		diff(t, b1, b)
+		return
+	}
+
+	// should get back to original
+	buf1.Reset()
+	if err := Compact(&buf1, b); err != nil {
+		t.Fatalf("Compact: %v", err)
+	}
+	b1 = buf1.Bytes()
+	if bytes.Compare(b1, jsonBig) != 0 {
+		t.Error("Compact(Indent(jsonBig)) != jsonBig")
+		diff(t, b1, jsonBig)
+		return
+	}
+}
+
+type indentErrorTest struct {
+	in  string
+	err error
+}
+
+var indentErrorTests = []indentErrorTest{
+	{`{"X": "foo", "Y"}`, &SyntaxError{"invalid character '}' after object key", 17}},
+	{`{"X": "foo" "Y": "bar"}`, &SyntaxError{"invalid character '\"' after object key:value pair", 13}},
+}
+
+func TestIndentErrors(t *testing.T) {
+	for i, tt := range indentErrorTests {
+		slice := make([]uint8, 0)
+		buf := bytes.NewBuffer(slice)
+		if err := Indent(buf, []uint8(tt.in), "", ""); err != nil {
+			if !reflect.DeepEqual(err, tt.err) {
+				t.Errorf("#%d: Indent: %#v", i, err)
+				continue
+			}
+		}
+	}
+}
+
+func TestNextValueBig(t *testing.T) {
+	initBig()
+	var scan scanner
+	item, rest, err := nextValue(jsonBig, &scan)
+	if err != nil {
+		t.Fatalf("nextValue: %s", err)
+	}
+	if len(item) != len(jsonBig) || &item[0] != &jsonBig[0] {
+		t.Errorf("invalid item: %d %d", len(item), len(jsonBig))
+	}
+	if len(rest) != 0 {
+		t.Errorf("invalid rest: %d", len(rest))
+	}
+
+	item, rest, err = nextValue(append(jsonBig, "HELLO WORLD"...), &scan)
+	if err != nil {
+		t.Fatalf("nextValue extra: %s", err)
+	}
+	if len(item) != len(jsonBig) {
+		t.Errorf("invalid item: %d %d", len(item), len(jsonBig))
+	}
+	if string(rest) != "HELLO WORLD" {
+		t.Errorf("invalid rest: %d", len(rest))
+	}
+}
+
+func BenchmarkSkipValue(b *testing.B) {
+	initBig()
+	var scan scanner
+	for i := 0; i < b.N; i++ {
+		nextValue(jsonBig, &scan)
+	}
+	b.SetBytes(int64(len(jsonBig)))
+}
+
+func diff(t *testing.T, a, b []byte) {
+	for i := 0; ; i++ {
+		if i >= len(a) || i >= len(b) || a[i] != b[i] {
+			j := i - 10
+			if j < 0 {
+				j = 0
+			}
+			t.Errorf("diverge at %d: «%s» vs «%s»", i, trim(a[j:]), trim(b[j:]))
+			return
+		}
+	}
+}
+
+func trim(b []byte) []byte {
+	if len(b) > 20 {
+		return b[0:20]
+	}
+	return b
+}
+
+// Generate a random JSON object.
+
+var jsonBig []byte
+
+const (
+	big   = 10000
+	small = 100
+)
+
+func initBig() {
+	n := big
+	if testing.Short() {
+		n = small
+	}
+	if len(jsonBig) != n {
+		b, err := Marshal(genValue(n))
+		if err != nil {
+			panic(err)
+		}
+		jsonBig = b
+	}
+}
+
+func genValue(n int) interface{} {
+	if n > 1 {
+		switch rand.Intn(2) {
+		case 0:
+			return genArray(n)
+		case 1:
+			return genMap(n)
+		}
+	}
+	switch rand.Intn(3) {
+	case 0:
+		return rand.Intn(2) == 0
+	case 1:
+		return rand.NormFloat64()
+	case 2:
+		return genString(30)
+	}
+	panic("unreachable")
+}
+
+func genString(stddev float64) string {
+	n := int(math.Abs(rand.NormFloat64()*stddev + stddev/2))
+	c := make([]rune, n)
+	for i := range c {
+		f := math.Abs(rand.NormFloat64()*64 + 32)
+		if f > 0x10ffff {
+			f = 0x10ffff
+		}
+		c[i] = rune(f)
+	}
+	return string(c)
+}
+
+func genArray(n int) []interface{} {
+	f := int(math.Abs(rand.NormFloat64()) * math.Min(10, float64(n/2)))
+	if f > n {
+		f = n
+	}
+	if n > 0 && f == 0 {
+		f = 1
+	}
+	x := make([]interface{}, f)
+	for i := range x {
+		x[i] = genValue(((i+1)*n)/f - (i*n)/f)
+	}
+	return x
+}
+
+func genMap(n int) map[string]interface{} {
+	f := int(math.Abs(rand.NormFloat64()) * math.Min(10, float64(n/2)))
+	if f > n {
+		f = n
+	}
+	if n > 0 && f == 0 {
+		f = 1
+	}
+	x := make(map[string]interface{})
+	for i := 0; i < f; i++ {
+		x[genString(10)] = genValue(((i+1)*n)/f - (i*n)/f)
+	}
+	return x
+}
diff --git a/libgo/go/encoding/json/stream.go b/libgo/go/encoding/json/stream.go
new file mode 100644
index 00000000000..f2476395023
--- /dev/null
+++ b/libgo/go/encoding/json/stream.go
@@ -0,0 +1,185 @@
+// Copyright 2010 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package json
+
+import (
+	"errors"
+	"io"
+)
+
+// A Decoder reads and decodes JSON objects from an input stream.
+type Decoder struct {
+	r    io.Reader
+	buf  []byte
+	d    decodeState
+	scan scanner
+	err  error
+}
+
+// NewDecoder returns a new decoder that reads from r.
+func NewDecoder(r io.Reader) *Decoder {
+	return &Decoder{r: r}
+}
+
+// Decode reads the next JSON-encoded value from its
+// input and stores it in the value pointed to by v.
+//
+// See the documentation for Unmarshal for details about
+// the conversion of JSON into a Go value.
+func (dec *Decoder) Decode(v interface{}) error {
+	if dec.err != nil {
+		return dec.err
+	}
+
+	n, err := dec.readValue()
+	if err != nil {
+		return err
+	}
+
+	// Don't save err from unmarshal into dec.err:
+	// the connection is still usable since we read a complete JSON
+	// object from it before the error happened.
+	dec.d.init(dec.buf[0:n])
+	err = dec.d.unmarshal(v)
+
+	// Slide rest of data down.
+	rest := copy(dec.buf, dec.buf[n:])
+	dec.buf = dec.buf[0:rest]
+
+	return err
+}
+
+// readValue reads a JSON value into dec.buf.
+// It returns the length of the encoding.
+func (dec *Decoder) readValue() (int, error) {
+	dec.scan.reset()
+
+	scanp := 0
+	var err error
+Input:
+	for {
+		// Look in the buffer for a new value.
+		for i, c := range dec.buf[scanp:] {
+			dec.scan.bytes++
+			v := dec.scan.step(&dec.scan, int(c))
+			if v == scanEnd {
+				scanp += i
+				break Input
+			}
+			// scanEnd is delayed one byte.
+			// We might block trying to get that byte from src,
+			// so instead invent a space byte.
+			if v == scanEndObject && dec.scan.step(&dec.scan, ' ') == scanEnd {
+				scanp += i + 1
+				break Input
+			}
+			if v == scanError {
+				dec.err = dec.scan.err
+				return 0, dec.scan.err
+			}
+		}
+		scanp = len(dec.buf)
+
+		// Did the last read have an error?
+		// Delayed until now to allow buffer scan.
+		if err != nil {
+			if err == io.EOF {
+				if dec.scan.step(&dec.scan, ' ') == scanEnd {
+					break Input
+				}
+				if nonSpace(dec.buf) {
+					err = io.ErrUnexpectedEOF
+				}
+			}
+			dec.err = err
+			return 0, err
+		}
+
+		// Make room to read more into the buffer.
+		const minRead = 512
+		if cap(dec.buf)-len(dec.buf) < minRead {
+			newBuf := make([]byte, len(dec.buf), 2*cap(dec.buf)+minRead)
+			copy(newBuf, dec.buf)
+			dec.buf = newBuf
+		}
+
+		// Read.  Delay error for next iteration (after scan).
+		var n int
+		n, err = dec.r.Read(dec.buf[len(dec.buf):cap(dec.buf)])
+		dec.buf = dec.buf[0 : len(dec.buf)+n]
+	}
+	return scanp, nil
+}
+
+func nonSpace(b []byte) bool {
+	for _, c := range b {
+		if !isSpace(rune(c)) {
+			return true
+		}
+	}
+	return false
+}
+
+// An Encoder writes JSON objects to an output stream.
+type Encoder struct {
+	w   io.Writer
+	e   encodeState
+	err error
+}
+
+// NewEncoder returns a new encoder that writes to w.
+func NewEncoder(w io.Writer) *Encoder {
+	return &Encoder{w: w}
+}
+
+// Encode writes the JSON encoding of v to the connection.
+//
+// See the documentation for Marshal for details about the
+// conversion of Go values to JSON.
+func (enc *Encoder) Encode(v interface{}) error {
+	if enc.err != nil {
+		return enc.err
+	}
+	enc.e.Reset()
+	err := enc.e.marshal(v)
+	if err != nil {
+		return err
+	}
+
+	// Terminate each value with a newline.
+	// This makes the output look a little nicer
+	// when debugging, and some kind of space
+	// is required if the encoded value was a number,
+	// so that the reader knows there aren't more
+	// digits coming.
+	enc.e.WriteByte('\n')
+
+	if _, err = enc.w.Write(enc.e.Bytes()); err != nil {
+		enc.err = err
+	}
+	return err
+}
+
+// RawMessage is a raw encoded JSON object.
+// It implements Marshaler and Unmarshaler and can
+// be used to delay JSON decoding or precompute a JSON encoding.
+type RawMessage []byte
+
+// MarshalJSON returns *m as the JSON encoding of m.
+func (m *RawMessage) MarshalJSON() ([]byte, error) {
+	return *m, nil
+}
+
+// UnmarshalJSON sets *m to a copy of data.
+func (m *RawMessage) UnmarshalJSON(data []byte) error {
+	if m == nil {
+		return errors.New("json.RawMessage: UnmarshalJSON on nil pointer")
+	}
+	*m = append((*m)[0:0], data...)
+	return nil
+}
+
+var _ Marshaler = (*RawMessage)(nil)
+var _ Unmarshaler = (*RawMessage)(nil)
diff --git a/libgo/go/encoding/json/stream_test.go b/libgo/go/encoding/json/stream_test.go
new file mode 100644
index 00000000000..ce5a7e6d656
--- /dev/null
+++ b/libgo/go/encoding/json/stream_test.go
@@ -0,0 +1,147 @@
+// Copyright 2010 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package json
+
+import (
+	"bytes"
+	"reflect"
+	"testing"
+)
+
+// Test values for the stream test.
+// One of each JSON kind.
+var streamTest = []interface{}{
+	0.1,
+	"hello",
+	nil,
+	true,
+	false,
+	[]interface{}{"a", "b", "c"},
+	map[string]interface{}{"K": "Kelvin", "ß": "long s"},
+	3.14, // another value to make sure something can follow map
+}
+
+var streamEncoded = `0.1
+"hello"
+null
+true
+false
+["a","b","c"]
+{"ß":"long s","K":"Kelvin"}
+3.14
+`
+
+func TestEncoder(t *testing.T) {
+	for i := 0; i <= len(streamTest); i++ {
+		var buf bytes.Buffer
+		enc := NewEncoder(&buf)
+		for j, v := range streamTest[0:i] {
+			if err := enc.Encode(v); err != nil {
+				t.Fatalf("encode #%d: %v", j, err)
+			}
+		}
+		if have, want := buf.String(), nlines(streamEncoded, i); have != want {
+			t.Errorf("encoding %d items: mismatch", i)
+			diff(t, []byte(have), []byte(want))
+			break
+		}
+	}
+}
+
+func TestDecoder(t *testing.T) {
+	for i := 0; i <= len(streamTest); i++ {
+		// Use stream without newlines as input,
+		// just to stress the decoder even more.
+		// Our test input does not include back-to-back numbers.
+		// Otherwise stripping the newlines would
+		// merge two adjacent JSON values.
+		var buf bytes.Buffer
+		for _, c := range nlines(streamEncoded, i) {
+			if c != '\n' {
+				buf.WriteRune(c)
+			}
+		}
+		out := make([]interface{}, i)
+		dec := NewDecoder(&buf)
+		for j := range out {
+			if err := dec.Decode(&out[j]); err != nil {
+				t.Fatalf("decode #%d/%d: %v", j, i, err)
+			}
+		}
+		if !reflect.DeepEqual(out, streamTest[0:i]) {
+			t.Errorf("decoding %d items: mismatch", i)
+			for j := range out {
+				if !reflect.DeepEqual(out[j], streamTest[j]) {
+					t.Errorf("#%d: have %v want %v", j, out[j], streamTest[j])
+				}
+			}
+			break
+		}
+	}
+}
+
+func nlines(s string, n int) string {
+	if n <= 0 {
+		return ""
+	}
+	for i, c := range s {
+		if c == '\n' {
+			if n--; n == 0 {
+				return s[0 : i+1]
+			}
+		}
+	}
+	return s
+}
+
+func TestRawMessage(t *testing.T) {
+	// TODO(rsc): Should not need the * in *RawMessage
+	var data struct {
+		X  float64
+		Id *RawMessage
+		Y  float32
+	}
+	const raw = `["\u0056",null]`
+	const msg = `{"X":0.1,"Id":["\u0056",null],"Y":0.2}`
+	err := Unmarshal([]byte(msg), &data)
+	if err != nil {
+		t.Fatalf("Unmarshal: %v", err)
+	}
+	if string([]byte(*data.Id)) != raw {
+		t.Fatalf("Raw mismatch: have %#q want %#q", []byte(*data.Id), raw)
+	}
+	b, err := Marshal(&data)
+	if err != nil {
+		t.Fatalf("Marshal: %v", err)
+	}
+	if string(b) != msg {
+		t.Fatalf("Marshal: have %#q want %#q", b, msg)
+	}
+}
+
+func TestNullRawMessage(t *testing.T) {
+	// TODO(rsc): Should not need the * in *RawMessage
+	var data struct {
+		X  float64
+		Id *RawMessage
+		Y  float32
+	}
+	data.Id = new(RawMessage)
+	const msg = `{"X":0.1,"Id":null,"Y":0.2}`
+	err := Unmarshal([]byte(msg), &data)
+	if err != nil {
+		t.Fatalf("Unmarshal: %v", err)
+	}
+	if data.Id != nil {
+		t.Fatalf("Raw mismatch: have non-nil, want nil")
+	}
+	b, err := Marshal(&data)
+	if err != nil {
+		t.Fatalf("Marshal: %v", err)
+	}
+	if string(b) != msg {
+		t.Fatalf("Marshal: have %#q want %#q", b, msg)
+	}
+}
diff --git a/libgo/go/encoding/json/tagkey_test.go b/libgo/go/encoding/json/tagkey_test.go
new file mode 100644
index 00000000000..31fe2be3621
--- /dev/null
+++ b/libgo/go/encoding/json/tagkey_test.go
@@ -0,0 +1,95 @@
+// Copyright 2011 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package json
+
+import (
+	"testing"
+)
+
+type basicLatin2xTag struct {
+	V string `json:"$-"`
+}
+
+type basicLatin3xTag struct {
+	V string `json:"0123456789"`
+}
+
+type basicLatin4xTag struct {
+	V string `json:"ABCDEFGHIJKLMO"`
+}
+
+type basicLatin5xTag struct {
+	V string `json:"PQRSTUVWXYZ_"`
+}
+
+type basicLatin6xTag struct {
+	V string `json:"abcdefghijklmno"`
+}
+
+type basicLatin7xTag struct {
+	V string `json:"pqrstuvwxyz"`
+}
+
+type miscPlaneTag struct {
+	V string `json:"色は匂へど"`
+}
+
+type emptyTag struct {
+	W string
+}
+
+type misnamedTag struct {
+	X string `jsom:"Misnamed"`
+}
+
+type badFormatTag struct {
+	Y string `:"BadFormat"`
+}
+
+type badCodeTag struct {
+	Z string `json:" !\"#%&'()*+,./"`
+}
+
+var structTagObjectKeyTests = []struct {
+	raw   interface{}
+	value string
+	key   string
+}{
+	{basicLatin2xTag{"2x"}, "2x", "$-"},
+	{basicLatin3xTag{"3x"}, "3x", "0123456789"},
+	{basicLatin4xTag{"4x"}, "4x", "ABCDEFGHIJKLMO"},
+	{basicLatin5xTag{"5x"}, "5x", "PQRSTUVWXYZ_"},
+	{basicLatin6xTag{"6x"}, "6x", "abcdefghijklmno"},
+	{basicLatin7xTag{"7x"}, "7x", "pqrstuvwxyz"},
+	{miscPlaneTag{"いろはにほへと"}, "いろはにほへと", "色は匂へど"},
+	{emptyTag{"Pour Moi"}, "Pour Moi", "W"},
+	{misnamedTag{"Animal Kingdom"}, "Animal Kingdom", "X"},
+	{badFormatTag{"Orfevre"}, "Orfevre", "Y"},
+	{badCodeTag{"Reliable Man"}, "Reliable Man", "Z"},
+}
+
+func TestStructTagObjectKey(t *testing.T) {
+	for _, tt := range structTagObjectKeyTests {
+		b, err := Marshal(tt.raw)
+		if err != nil {
+			t.Fatalf("Marshal(%#q) failed: %v", tt.raw, err)
+		}
+		var f interface{}
+		err = Unmarshal(b, &f)
+		if err != nil {
+			t.Fatalf("Unmarshal(%#q) failed: %v", b, err)
+		}
+		for i, v := range f.(map[string]interface{}) {
+			switch i {
+			case tt.key:
+				if s, ok := v.(string); !ok || s != tt.value {
+					t.Fatalf("Unexpected value: %#q, want %v", s, tt.value)
+				}
+			default:
+				t.Fatalf("Unexpected key: %#q", i)
+			}
+		}
+	}
+}
diff --git a/libgo/go/encoding/json/tags.go b/libgo/go/encoding/json/tags.go
new file mode 100644
index 00000000000..58cda2027c6
--- /dev/null
+++ b/libgo/go/encoding/json/tags.go
@@ -0,0 +1,44 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package json
+
+import (
+	"strings"
+)
+
+// tagOptions is the string following a comma in a struct field's "json"
+// tag, or the empty string. It does not include the leading comma.
+type tagOptions string
+
+// parseTag splits a struct field's json tag into its name and
+// comma-separated options.
+func parseTag(tag string) (string, tagOptions) {
+	if idx := strings.Index(tag, ","); idx != -1 {
+		return tag[:idx], tagOptions(tag[idx+1:])
+	}
+	return tag, tagOptions("")
+}
+
+// Contains returns whether checks that a comma-separated list of options
+// contains a particular substr flag. substr must be surrounded by a
+// string boundary or commas.
+func (o tagOptions) Contains(optionName string) bool {
+	if len(o) == 0 {
+		return false
+	}
+	s := string(o)
+	for s != "" {
+		var next string
+		i := strings.Index(s, ",")
+		if i >= 0 {
+			s, next = s[:i], s[i+1:]
+		}
+		if s == optionName {
+			return true
+		}
+		s = next
+	}
+	return false
+}
diff --git a/libgo/go/encoding/json/tags_test.go b/libgo/go/encoding/json/tags_test.go
new file mode 100644
index 00000000000..91fb18831e2
--- /dev/null
+++ b/libgo/go/encoding/json/tags_test.go
@@ -0,0 +1,28 @@
+// Copyright 2011 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package json
+
+import (
+	"testing"
+)
+
+func TestTagParsing(t *testing.T) {
+	name, opts := parseTag("field,foobar,foo")
+	if name != "field" {
+		t.Fatalf("name = %q, want field", name)
+	}
+	for _, tt := range []struct {
+		opt  string
+		want bool
+	}{
+		{"foobar", true},
+		{"foo", true},
+		{"bar", false},
+	} {
+		if opts.Contains(tt.opt) != tt.want {
+			t.Errorf("Contains(%q) = %v", tt.opt, !tt.want)
+		}
+	}
+}
diff --git a/libgo/go/encoding/xml/atom_test.go b/libgo/go/encoding/xml/atom_test.go
new file mode 100644
index 00000000000..d365510bf58
--- /dev/null
+++ b/libgo/go/encoding/xml/atom_test.go
@@ -0,0 +1,50 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package xml
+
+var atomValue = &Feed{
+	Title:   "Example Feed",
+	Link:    []Link{{Href: "http://example.org/"}},
+	Updated: ParseTime("2003-12-13T18:30:02Z"),
+	Author:  Person{Name: "John Doe"},
+	Id:      "urn:uuid:60a76c80-d399-11d9-b93C-0003939e0af6",
+
+	Entry: []Entry{
+		{
+			Title:   "Atom-Powered Robots Run Amok",
+			Link:    []Link{{Href: "http://example.org/2003/12/13/atom03"}},
+			Id:      "urn:uuid:1225c695-cfb8-4ebb-aaaa-80da344efa6a",
+			Updated: ParseTime("2003-12-13T18:30:02Z"),
+			Summary: NewText("Some text."),
+		},
+	},
+}
+
+var atomXml = `` +
+	`<feed xmlns="http://www.w3.org/2005/Atom">` +
+	`<Title>Example Feed</Title>` +
+	`<Id>urn:uuid:60a76c80-d399-11d9-b93C-0003939e0af6</Id>` +
+	`<Link href="http://example.org/"></Link>` +
+	`<Updated>2003-12-13T18:30:02Z</Updated>` +
+	`<Author><Name>John Doe</Name><URI></URI><Email></Email></Author>` +
+	`<Entry>` +
+	`<Title>Atom-Powered Robots Run Amok</Title>` +
+	`<Id>urn:uuid:1225c695-cfb8-4ebb-aaaa-80da344efa6a</Id>` +
+	`<Link href="http://example.org/2003/12/13/atom03"></Link>` +
+	`<Updated>2003-12-13T18:30:02Z</Updated>` +
+	`<Author><Name></Name><URI></URI><Email></Email></Author>` +
+	`<Summary>Some text.</Summary>` +
+	`</Entry>` +
+	`</feed>`
+
+func ParseTime(str string) Time {
+	return Time(str)
+}
+
+func NewText(text string) Text {
+	return Text{
+		Body: text,
+	}
+}
diff --git a/libgo/go/encoding/xml/embed_test.go b/libgo/go/encoding/xml/embed_test.go
new file mode 100644
index 00000000000..ec7f478bec3
--- /dev/null
+++ b/libgo/go/encoding/xml/embed_test.go
@@ -0,0 +1,124 @@
+// Copyright 2010 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package xml
+
+import "testing"
+
+type C struct {
+	Name string
+	Open bool
+}
+
+type A struct {
+	XMLName Name `xml:"http://domain a"`
+	C
+	B      B
+	FieldA string
+}
+
+type B struct {
+	XMLName Name `xml:"b"`
+	C
+	FieldB string
+}
+
+const _1a = `
+<?xml version="1.0" encoding="UTF-8"?>
+<a xmlns="http://domain">
+  <name>KmlFile</name>
+  <open>1</open>
+  <b>
+    <name>Absolute</name>
+    <open>0</open>
+    <fieldb>bar</fieldb>
+  </b>
+  <fielda>foo</fielda>
+</a>
+`
+
+// Tests that embedded structs are marshalled.
+func TestEmbedded1(t *testing.T) {
+	var a A
+	if e := Unmarshal(StringReader(_1a), &a); e != nil {
+		t.Fatalf("Unmarshal: %s", e)
+	}
+	if a.FieldA != "foo" {
+		t.Fatalf("Unmarshal: expected 'foo' but found '%s'", a.FieldA)
+	}
+	if a.Name != "KmlFile" {
+		t.Fatalf("Unmarshal: expected 'KmlFile' but found '%s'", a.Name)
+	}
+	if !a.Open {
+		t.Fatal("Unmarshal: expected 'true' but found otherwise")
+	}
+	if a.B.FieldB != "bar" {
+		t.Fatalf("Unmarshal: expected 'bar' but found '%s'", a.B.FieldB)
+	}
+	if a.B.Name != "Absolute" {
+		t.Fatalf("Unmarshal: expected 'Absolute' but found '%s'", a.B.Name)
+	}
+	if a.B.Open {
+		t.Fatal("Unmarshal: expected 'false' but found otherwise")
+	}
+}
+
+type A2 struct {
+	XMLName Name `xml:"http://domain a"`
+	XY      string
+	Xy      string
+}
+
+const _2a = `
+<?xml version="1.0" encoding="UTF-8"?>
+<a xmlns="http://domain">
+  <xy>foo</xy>
+</a>
+`
+
+// Tests that conflicting field names get excluded.
+func TestEmbedded2(t *testing.T) {
+	var a A2
+	if e := Unmarshal(StringReader(_2a), &a); e != nil {
+		t.Fatalf("Unmarshal: %s", e)
+	}
+	if a.XY != "" {
+		t.Fatalf("Unmarshal: expected empty string but found '%s'", a.XY)
+	}
+	if a.Xy != "" {
+		t.Fatalf("Unmarshal: expected empty string but found '%s'", a.Xy)
+	}
+}
+
+type A3 struct {
+	XMLName Name `xml:"http://domain a"`
+	xy      string
+}
+
+// Tests that private fields are not set.
+func TestEmbedded3(t *testing.T) {
+	var a A3
+	if e := Unmarshal(StringReader(_2a), &a); e != nil {
+		t.Fatalf("Unmarshal: %s", e)
+	}
+	if a.xy != "" {
+		t.Fatalf("Unmarshal: expected empty string but found '%s'", a.xy)
+	}
+}
+
+type A4 struct {
+	XMLName Name `xml:"http://domain a"`
+	Any     string
+}
+
+// Tests that private fields are not set.
+func TestEmbedded4(t *testing.T) {
+	var a A4
+	if e := Unmarshal(StringReader(_2a), &a); e != nil {
+		t.Fatalf("Unmarshal: %s", e)
+	}
+	if a.Any != "foo" {
+		t.Fatalf("Unmarshal: expected 'foo' but found '%s'", a.Any)
+	}
+}
diff --git a/libgo/go/encoding/xml/marshal.go b/libgo/go/encoding/xml/marshal.go
new file mode 100644
index 00000000000..691b70d2510
--- /dev/null
+++ b/libgo/go/encoding/xml/marshal.go
@@ -0,0 +1,304 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package xml
+
+import (
+	"bufio"
+	"io"
+	"reflect"
+	"strconv"
+	"strings"
+)
+
+const (
+	// A generic XML header suitable for use with the output of Marshal and
+	// MarshalIndent.  This is not automatically added to any output of this
+	// package, it is provided as a convenience.
+	Header = `<?xml version="1.0" encoding="UTF-8"?>` + "\n"
+)
+
+// A Marshaler can produce well-formatted XML representing its internal state.
+// It is used by both Marshal and MarshalIndent.
+type Marshaler interface {
+	MarshalXML() ([]byte, error)
+}
+
+type printer struct {
+	*bufio.Writer
+}
+
+// Marshal writes an XML-formatted representation of v to w.
+//
+// If v implements Marshaler, then Marshal calls its MarshalXML method.
+// Otherwise, Marshal uses the following procedure to create the XML.
+//
+// Marshal handles an array or slice by marshalling each of the elements.
+// Marshal handles a pointer by marshalling the value it points at or, if the
+// pointer is nil, by writing nothing.  Marshal handles an interface value by
+// marshalling the value it contains or, if the interface value is nil, by
+// writing nothing.  Marshal handles all other data by writing one or more XML
+// elements containing the data.
+//
+// The name for the XML elements is taken from, in order of preference:
+//     - the tag on an XMLName field, if the data is a struct
+//     - the value of an XMLName field of type xml.Name
+//     - the tag of the struct field used to obtain the data
+//     - the name of the struct field used to obtain the data
+//     - the name '???'.
+//
+// The XML element for a struct contains marshalled elements for each of the
+// exported fields of the struct, with these exceptions:
+//     - the XMLName field, described above, is omitted.
+//     - a field with tag "attr" becomes an attribute in the XML element.
+//     - a field with tag "chardata" is written as character data,
+//        not as an XML element.
+//     - a field with tag "innerxml" is written verbatim,
+//        not subject to the usual marshalling procedure.
+//
+// If a field uses a tag "a>b>c", then the element c will be nested inside
+// parent elements a and b.  Fields that appear next to each other that name
+// the same parent will be enclosed in one XML element.  For example:
+//
+//	type Result struct {
+//		XMLName   xml.Name `xml:"result"`
+//		FirstName string   `xml:"person>name>first"`
+//		LastName  string   `xml:"person>name>last"`
+//		Age       int      `xml:"person>age"`
+//	}
+//
+//	xml.Marshal(w, &Result{FirstName: "John", LastName: "Doe", Age: 42})
+//
+// would be marshalled as:
+//
+//	<result>
+//		<person>
+//			<name>
+//				<first>John</first>
+//				<last>Doe</last>
+//			</name>
+//			<age>42</age>
+//		</person>
+//	</result>
+//
+// Marshal will return an error if asked to marshal a channel, function, or map.
+func Marshal(w io.Writer, v interface{}) (err error) {
+	p := &printer{bufio.NewWriter(w)}
+	err = p.marshalValue(reflect.ValueOf(v), "???")
+	p.Flush()
+	return err
+}
+
+func (p *printer) marshalValue(val reflect.Value, name string) error {
+	if !val.IsValid() {
+		return nil
+	}
+
+	kind := val.Kind()
+	typ := val.Type()
+
+	// Try Marshaler
+	if typ.NumMethod() > 0 {
+		if marshaler, ok := val.Interface().(Marshaler); ok {
+			bytes, err := marshaler.MarshalXML()
+			if err != nil {
+				return err
+			}
+			p.Write(bytes)
+			return nil
+		}
+	}
+
+	// Drill into pointers/interfaces
+	if kind == reflect.Ptr || kind == reflect.Interface {
+		if val.IsNil() {
+			return nil
+		}
+		return p.marshalValue(val.Elem(), name)
+	}
+
+	// Slices and arrays iterate over the elements. They do not have an enclosing tag.
+	if (kind == reflect.Slice || kind == reflect.Array) && typ.Elem().Kind() != reflect.Uint8 {
+		for i, n := 0, val.Len(); i < n; i++ {
+			if err := p.marshalValue(val.Index(i), name); err != nil {
+				return err
+			}
+		}
+		return nil
+	}
+
+	// Find XML name
+	xmlns := ""
+	if kind == reflect.Struct {
+		if f, ok := typ.FieldByName("XMLName"); ok {
+			if tag := f.Tag.Get("xml"); tag != "" {
+				if i := strings.Index(tag, " "); i >= 0 {
+					xmlns, name = tag[:i], tag[i+1:]
+				} else {
+					name = tag
+				}
+			} else if v, ok := val.FieldByIndex(f.Index).Interface().(Name); ok && v.Local != "" {
+				xmlns, name = v.Space, v.Local
+			}
+		}
+	}
+
+	p.WriteByte('<')
+	p.WriteString(name)
+
+	// Attributes
+	if kind == reflect.Struct {
+		if len(xmlns) > 0 {
+			p.WriteString(` xmlns="`)
+			Escape(p, []byte(xmlns))
+			p.WriteByte('"')
+		}
+
+		for i, n := 0, typ.NumField(); i < n; i++ {
+			if f := typ.Field(i); f.PkgPath == "" && f.Tag.Get("xml") == "attr" {
+				if f.Type.Kind() == reflect.String {
+					if str := val.Field(i).String(); str != "" {
+						p.WriteByte(' ')
+						p.WriteString(strings.ToLower(f.Name))
+						p.WriteString(`="`)
+						Escape(p, []byte(str))
+						p.WriteByte('"')
+					}
+				}
+			}
+		}
+	}
+	p.WriteByte('>')
+
+	switch k := val.Kind(); k {
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		p.WriteString(strconv.Itoa64(val.Int()))
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+		p.WriteString(strconv.Uitoa64(val.Uint()))
+	case reflect.Float32, reflect.Float64:
+		p.WriteString(strconv.Ftoa64(val.Float(), 'g', -1))
+	case reflect.String:
+		Escape(p, []byte(val.String()))
+	case reflect.Bool:
+		p.WriteString(strconv.Btoa(val.Bool()))
+	case reflect.Array:
+		// will be [...]byte
+		bytes := make([]byte, val.Len())
+		for i := range bytes {
+			bytes[i] = val.Index(i).Interface().(byte)
+		}
+		Escape(p, bytes)
+	case reflect.Slice:
+		// will be []byte
+		bytes := val.Interface().([]byte)
+		Escape(p, bytes)
+	case reflect.Struct:
+		s := parentStack{printer: p}
+		for i, n := 0, val.NumField(); i < n; i++ {
+			if f := typ.Field(i); f.Name != "XMLName" && f.PkgPath == "" {
+				name := f.Name
+				vf := val.Field(i)
+				switch tag := f.Tag.Get("xml"); tag {
+				case "":
+					s.trim(nil)
+				case "chardata":
+					if tk := f.Type.Kind(); tk == reflect.String {
+						Escape(p, []byte(vf.String()))
+					} else if tk == reflect.Slice {
+						if elem, ok := vf.Interface().([]byte); ok {
+							Escape(p, elem)
+						}
+					}
+					continue
+				case "innerxml":
+					iface := vf.Interface()
+					switch raw := iface.(type) {
+					case []byte:
+						p.Write(raw)
+						continue
+					case string:
+						p.WriteString(raw)
+						continue
+					}
+				case "attr":
+					continue
+				default:
+					parents := strings.Split(tag, ">")
+					if len(parents) == 1 {
+						parents, name = nil, tag
+					} else {
+						parents, name = parents[:len(parents)-1], parents[len(parents)-1]
+						if parents[0] == "" {
+							parents[0] = f.Name
+						}
+					}
+
+					s.trim(parents)
+					if !(vf.Kind() == reflect.Ptr || vf.Kind() == reflect.Interface) || !vf.IsNil() {
+						s.push(parents[len(s.stack):])
+					}
+				}
+
+				if err := p.marshalValue(vf, name); err != nil {
+					return err
+				}
+			}
+		}
+		s.trim(nil)
+	default:
+		return &UnsupportedTypeError{typ}
+	}
+
+	p.WriteByte('<')
+	p.WriteByte('/')
+	p.WriteString(name)
+	p.WriteByte('>')
+
+	return nil
+}
+
+type parentStack struct {
+	*printer
+	stack []string
+}
+
+// trim updates the XML context to match the longest common prefix of the stack
+// and the given parents.  A closing tag will be written for every parent
+// popped.  Passing a zero slice or nil will close all the elements.
+func (s *parentStack) trim(parents []string) {
+	split := 0
+	for ; split < len(parents) && split < len(s.stack); split++ {
+		if parents[split] != s.stack[split] {
+			break
+		}
+	}
+
+	for i := len(s.stack) - 1; i >= split; i-- {
+		s.WriteString("</")
+		s.WriteString(s.stack[i])
+		s.WriteByte('>')
+	}
+
+	s.stack = parents[:split]
+}
+
+// push adds parent elements to the stack and writes open tags.
+func (s *parentStack) push(parents []string) {
+	for i := 0; i < len(parents); i++ {
+		s.WriteString("<")
+		s.WriteString(parents[i])
+		s.WriteByte('>')
+	}
+	s.stack = append(s.stack, parents...)
+}
+
+// A MarshalXMLError is returned when Marshal or MarshalIndent encounter a type
+// that cannot be converted into XML.
+type UnsupportedTypeError struct {
+	Type reflect.Type
+}
+
+func (e *UnsupportedTypeError) Error() string {
+	return "xml: unsupported type: " + e.Type.String()
+}
diff --git a/libgo/go/encoding/xml/marshal_test.go b/libgo/go/encoding/xml/marshal_test.go
new file mode 100644
index 00000000000..a6f7d2d0c27
--- /dev/null
+++ b/libgo/go/encoding/xml/marshal_test.go
@@ -0,0 +1,423 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package xml
+
+import (
+	"bytes"
+	"reflect"
+	"strconv"
+	"strings"
+	"testing"
+)
+
+type DriveType int
+
+const (
+	HyperDrive DriveType = iota
+	ImprobabilityDrive
+)
+
+type Passenger struct {
+	Name   []string `xml:"name"`
+	Weight float32  `xml:"weight"`
+}
+
+type Ship struct {
+	XMLName Name `xml:"spaceship"`
+
+	Name      string       `xml:"attr"`
+	Pilot     string       `xml:"attr"`
+	Drive     DriveType    `xml:"drive"`
+	Age       uint         `xml:"age"`
+	Passenger []*Passenger `xml:"passenger"`
+	secret    string
+}
+
+type RawXML string
+
+func (rx RawXML) MarshalXML() ([]byte, error) {
+	return []byte(rx), nil
+}
+
+type NamedType string
+
+type Port struct {
+	XMLName Name   `xml:"port"`
+	Type    string `xml:"attr"`
+	Number  string `xml:"chardata"`
+}
+
+type Domain struct {
+	XMLName Name   `xml:"domain"`
+	Country string `xml:"attr"`
+	Name    []byte `xml:"chardata"`
+}
+
+type Book struct {
+	XMLName Name   `xml:"book"`
+	Title   string `xml:"chardata"`
+}
+
+type SecretAgent struct {
+	XMLName   Name   `xml:"agent"`
+	Handle    string `xml:"attr"`
+	Identity  string
+	Obfuscate string `xml:"innerxml"`
+}
+
+type NestedItems struct {
+	XMLName Name     `xml:"result"`
+	Items   []string `xml:">item"`
+	Item1   []string `xml:"Items>item1"`
+}
+
+type NestedOrder struct {
+	XMLName Name   `xml:"result"`
+	Field1  string `xml:"parent>c"`
+	Field2  string `xml:"parent>b"`
+	Field3  string `xml:"parent>a"`
+}
+
+type MixedNested struct {
+	XMLName Name   `xml:"result"`
+	A       string `xml:"parent1>a"`
+	B       string `xml:"b"`
+	C       string `xml:"parent1>parent2>c"`
+	D       string `xml:"parent1>d"`
+}
+
+type NilTest struct {
+	A interface{} `xml:"parent1>parent2>a"`
+	B interface{} `xml:"parent1>b"`
+	C interface{} `xml:"parent1>parent2>c"`
+}
+
+type Service struct {
+	XMLName Name    `xml:"service"`
+	Domain  *Domain `xml:"host>domain"`
+	Port    *Port   `xml:"host>port"`
+	Extra1  interface{}
+	Extra2  interface{} `xml:"host>extra2"`
+}
+
+var nilStruct *Ship
+
+var marshalTests = []struct {
+	Value     interface{}
+	ExpectXML string
+}{
+	// Test nil marshals to nothing
+	{Value: nil, ExpectXML: ``},
+	{Value: nilStruct, ExpectXML: ``},
+
+	// Test value types (no tag name, so ???)
+	{Value: true, ExpectXML: `<???>true</???>`},
+	{Value: int(42), ExpectXML: `<???>42</???>`},
+	{Value: int8(42), ExpectXML: `<???>42</???>`},
+	{Value: int16(42), ExpectXML: `<???>42</???>`},
+	{Value: int32(42), ExpectXML: `<???>42</???>`},
+	{Value: uint(42), ExpectXML: `<???>42</???>`},
+	{Value: uint8(42), ExpectXML: `<???>42</???>`},
+	{Value: uint16(42), ExpectXML: `<???>42</???>`},
+	{Value: uint32(42), ExpectXML: `<???>42</???>`},
+	{Value: float32(1.25), ExpectXML: `<???>1.25</???>`},
+	{Value: float64(1.25), ExpectXML: `<???>1.25</???>`},
+	{Value: uintptr(0xFFDD), ExpectXML: `<???>65501</???>`},
+	{Value: "gopher", ExpectXML: `<???>gopher</???>`},
+	{Value: []byte("gopher"), ExpectXML: `<???>gopher</???>`},
+	{Value: "</>", ExpectXML: `<???>&lt;/&gt;</???>`},
+	{Value: []byte("</>"), ExpectXML: `<???>&lt;/&gt;</???>`},
+	{Value: [3]byte{'<', '/', '>'}, ExpectXML: `<???>&lt;/&gt;</???>`},
+	{Value: NamedType("potato"), ExpectXML: `<???>potato</???>`},
+	{Value: []int{1, 2, 3}, ExpectXML: `<???>1</???><???>2</???><???>3</???>`},
+	{Value: [3]int{1, 2, 3}, ExpectXML: `<???>1</???><???>2</???><???>3</???>`},
+
+	// Test innerxml
+	{Value: RawXML("</>"), ExpectXML: `</>`},
+	{
+		Value: &SecretAgent{
+			Handle:    "007",
+			Identity:  "James Bond",
+			Obfuscate: "<redacted/>",
+		},
+		//ExpectXML: `<agent handle="007"><redacted/></agent>`,
+		ExpectXML: `<agent handle="007"><Identity>James Bond</Identity><redacted/></agent>`,
+	},
+
+	// Test structs
+	{Value: &Port{Type: "ssl", Number: "443"}, ExpectXML: `<port type="ssl">443</port>`},
+	{Value: &Port{Number: "443"}, ExpectXML: `<port>443</port>`},
+	{Value: &Port{Type: "<unix>"}, ExpectXML: `<port type="&lt;unix&gt;"></port>`},
+	{Value: &Domain{Name: []byte("google.com&friends")}, ExpectXML: `<domain>google.com&amp;friends</domain>`},
+	{Value: &Book{Title: "Pride & Prejudice"}, ExpectXML: `<book>Pride &amp; Prejudice</book>`},
+	{Value: atomValue, ExpectXML: atomXml},
+	{
+		Value: &Ship{
+			Name:  "Heart of Gold",
+			Pilot: "Computer",
+			Age:   1,
+			Drive: ImprobabilityDrive,
+			Passenger: []*Passenger{
+				&Passenger{
+					Name:   []string{"Zaphod", "Beeblebrox"},
+					Weight: 7.25,
+				},
+				&Passenger{
+					Name:   []string{"Trisha", "McMillen"},
+					Weight: 5.5,
+				},
+				&Passenger{
+					Name:   []string{"Ford", "Prefect"},
+					Weight: 7,
+				},
+				&Passenger{
+					Name:   []string{"Arthur", "Dent"},
+					Weight: 6.75,
+				},
+			},
+		},
+		ExpectXML: `<spaceship name="Heart of Gold" pilot="Computer">` +
+			`<drive>` + strconv.Itoa(int(ImprobabilityDrive)) + `</drive>` +
+			`<age>1</age>` +
+			`<passenger>` +
+			`<name>Zaphod</name>` +
+			`<name>Beeblebrox</name>` +
+			`<weight>7.25</weight>` +
+			`</passenger>` +
+			`<passenger>` +
+			`<name>Trisha</name>` +
+			`<name>McMillen</name>` +
+			`<weight>5.5</weight>` +
+			`</passenger>` +
+			`<passenger>` +
+			`<name>Ford</name>` +
+			`<name>Prefect</name>` +
+			`<weight>7</weight>` +
+			`</passenger>` +
+			`<passenger>` +
+			`<name>Arthur</name>` +
+			`<name>Dent</name>` +
+			`<weight>6.75</weight>` +
+			`</passenger>` +
+			`</spaceship>`,
+	},
+	// Test a>b
+	{
+		Value: NestedItems{Items: []string{}, Item1: []string{}},
+		ExpectXML: `<result>` +
+			`<Items>` +
+			`</Items>` +
+			`</result>`,
+	},
+	{
+		Value: NestedItems{Items: []string{}, Item1: []string{"A"}},
+		ExpectXML: `<result>` +
+			`<Items>` +
+			`<item1>A</item1>` +
+			`</Items>` +
+			`</result>`,
+	},
+	{
+		Value: NestedItems{Items: []string{"A", "B"}, Item1: []string{}},
+		ExpectXML: `<result>` +
+			`<Items>` +
+			`<item>A</item>` +
+			`<item>B</item>` +
+			`</Items>` +
+			`</result>`,
+	},
+	{
+		Value: NestedItems{Items: []string{"A", "B"}, Item1: []string{"C"}},
+		ExpectXML: `<result>` +
+			`<Items>` +
+			`<item>A</item>` +
+			`<item>B</item>` +
+			`<item1>C</item1>` +
+			`</Items>` +
+			`</result>`,
+	},
+	{
+		Value: NestedOrder{Field1: "C", Field2: "B", Field3: "A"},
+		ExpectXML: `<result>` +
+			`<parent>` +
+			`<c>C</c>` +
+			`<b>B</b>` +
+			`<a>A</a>` +
+			`</parent>` +
+			`</result>`,
+	},
+	{
+		Value: NilTest{A: "A", B: nil, C: "C"},
+		ExpectXML: `<???>` +
+			`<parent1>` +
+			`<parent2><a>A</a></parent2>` +
+			`<parent2><c>C</c></parent2>` +
+			`</parent1>` +
+			`</???>`,
+	},
+	{
+		Value: MixedNested{A: "A", B: "B", C: "C", D: "D"},
+		ExpectXML: `<result>` +
+			`<parent1><a>A</a></parent1>` +
+			`<b>B</b>` +
+			`<parent1>` +
+			`<parent2><c>C</c></parent2>` +
+			`<d>D</d>` +
+			`</parent1>` +
+			`</result>`,
+	},
+	{
+		Value:     Service{Port: &Port{Number: "80"}},
+		ExpectXML: `<service><host><port>80</port></host></service>`,
+	},
+	{
+		Value:     Service{},
+		ExpectXML: `<service></service>`,
+	},
+	{
+		Value: Service{Port: &Port{Number: "80"}, Extra1: "A", Extra2: "B"},
+		ExpectXML: `<service>` +
+			`<host><port>80</port></host>` +
+			`<Extra1>A</Extra1>` +
+			`<host><extra2>B</extra2></host>` +
+			`</service>`,
+	},
+	{
+		Value: Service{Port: &Port{Number: "80"}, Extra2: "example"},
+		ExpectXML: `<service>` +
+			`<host><port>80</port></host>` +
+			`<host><extra2>example</extra2></host>` +
+			`</service>`,
+	},
+}
+
+func TestMarshal(t *testing.T) {
+	for idx, test := range marshalTests {
+		buf := bytes.NewBuffer(nil)
+		err := Marshal(buf, test.Value)
+		if err != nil {
+			t.Errorf("#%d: Error: %s", idx, err)
+			continue
+		}
+		if got, want := buf.String(), test.ExpectXML; got != want {
+			if strings.Contains(want, "\n") {
+				t.Errorf("#%d: marshal(%#v) - GOT:\n%s\nWANT:\n%s", idx, test.Value, got, want)
+			} else {
+				t.Errorf("#%d: marshal(%#v) = %#q want %#q", idx, test.Value, got, want)
+			}
+		}
+	}
+}
+
+var marshalErrorTests = []struct {
+	Value interface{}
+	Err   string
+	Kind  reflect.Kind
+}{
+	{
+		Value: make(chan bool),
+		Err:   "xml: unsupported type: chan bool",
+		Kind:  reflect.Chan,
+	},
+	{
+		Value: map[string]string{
+			"question": "What do you get when you multiply six by nine?",
+			"answer":   "42",
+		},
+		Err:  "xml: unsupported type: map[string] string",
+		Kind: reflect.Map,
+	},
+	{
+		Value: map[*Ship]bool{nil: false},
+		Err:   "xml: unsupported type: map[*xml.Ship] bool",
+		Kind:  reflect.Map,
+	},
+}
+
+func TestMarshalErrors(t *testing.T) {
+	for idx, test := range marshalErrorTests {
+		buf := bytes.NewBuffer(nil)
+		err := Marshal(buf, test.Value)
+		if err == nil || err.Error() != test.Err {
+			t.Errorf("#%d: marshal(%#v) = [error] %q, want %q", idx, test.Value, err, test.Err)
+		}
+		if kind := err.(*UnsupportedTypeError).Type.Kind(); kind != test.Kind {
+			t.Errorf("#%d: marshal(%#v) = [error kind] %s, want %s", idx, test.Value, kind, test.Kind)
+		}
+	}
+}
+
+// Do invertibility testing on the various structures that we test
+func TestUnmarshal(t *testing.T) {
+	for i, test := range marshalTests {
+		// Skip the nil pointers
+		if i <= 1 {
+			continue
+		}
+
+		var dest interface{}
+
+		switch test.Value.(type) {
+		case *Ship, Ship:
+			dest = &Ship{}
+		case *Port, Port:
+			dest = &Port{}
+		case *Domain, Domain:
+			dest = &Domain{}
+		case *Feed, Feed:
+			dest = &Feed{}
+		default:
+			continue
+		}
+
+		buffer := bytes.NewBufferString(test.ExpectXML)
+		err := Unmarshal(buffer, dest)
+
+		// Don't compare XMLNames
+		switch fix := dest.(type) {
+		case *Ship:
+			fix.XMLName = Name{}
+		case *Port:
+			fix.XMLName = Name{}
+		case *Domain:
+			fix.XMLName = Name{}
+		case *Feed:
+			fix.XMLName = Name{}
+			fix.Author.InnerXML = ""
+			for i := range fix.Entry {
+				fix.Entry[i].Author.InnerXML = ""
+			}
+		}
+
+		if err != nil {
+			t.Errorf("#%d: unexpected error: %#v", i, err)
+		} else if got, want := dest, test.Value; !reflect.DeepEqual(got, want) {
+			t.Errorf("#%d: unmarshal(%#s) = %#v, want %#v", i, test.ExpectXML, got, want)
+		}
+	}
+}
+
+func BenchmarkMarshal(b *testing.B) {
+	idx := len(marshalTests) - 1
+	test := marshalTests[idx]
+
+	buf := bytes.NewBuffer(nil)
+	for i := 0; i < b.N; i++ {
+		Marshal(buf, test.Value)
+		buf.Truncate(0)
+	}
+}
+
+func BenchmarkUnmarshal(b *testing.B) {
+	idx := len(marshalTests) - 1
+	test := marshalTests[idx]
+	sm := &Ship{}
+	xml := []byte(test.ExpectXML)
+
+	for i := 0; i < b.N; i++ {
+		buffer := bytes.NewBuffer(xml)
+		Unmarshal(buffer, sm)
+	}
+}
diff --git a/libgo/go/encoding/xml/read.go b/libgo/go/encoding/xml/read.go
new file mode 100644
index 00000000000..c6a3d75a801
--- /dev/null
+++ b/libgo/go/encoding/xml/read.go
@@ -0,0 +1,630 @@
+// Copyright 2009 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package xml
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"io"
+	"reflect"
+	"strconv"
+	"strings"
+	"unicode"
+	"unicode/utf8"
+)
+
+// BUG(rsc): Mapping between XML elements and data structures is inherently flawed:
+// an XML element is an order-dependent collection of anonymous
+// values, while a data structure is an order-independent collection
+// of named values.
+// See package json for a textual representation more suitable
+// to data structures.
+
+// Unmarshal parses an XML element from r and uses the
+// reflect library to fill in an arbitrary struct, slice, or string
+// pointed at by val.  Well-formed data that does not fit
+// into val is discarded.
+//
+// For example, given these definitions:
+//
+//	type Email struct {
+//		Where string `xml:"attr"`
+//		Addr  string
+//	}
+//
+//	type Result struct {
+//		XMLName xml.Name `xml:"result"`
+//		Name	string
+//		Phone	string
+//		Email	[]Email
+//		Groups  []string `xml:"group>value"`
+//	}
+//
+//	result := Result{Name: "name", Phone: "phone", Email: nil}
+//
+// unmarshalling the XML input
+//
+//	<result>
+//		<email where="home">
+//			<addr>gre@example.com</addr>
+//		</email>
+//		<email where='work'>
+//			<addr>gre@work.com</addr>
+//		</email>
+//		<name>Grace R. Emlin</name>
+// 		<group>
+// 			<value>Friends</value>
+// 			<value>Squash</value>
+// 		</group>
+//		<address>123 Main Street</address>
+//	</result>
+//
+// via Unmarshal(r, &result) is equivalent to assigning
+//
+//	r = Result{xml.Name{"", "result"},
+//		"Grace R. Emlin", // name
+//		"phone",	  // no phone given
+//		[]Email{
+//			Email{"home", "gre@example.com"},
+//			Email{"work", "gre@work.com"},
+//		},
+//		[]string{"Friends", "Squash"},
+//	}
+//
+// Note that the field r.Phone has not been modified and
+// that the XML <address> element was discarded. Also, the field
+// Groups was assigned considering the element path provided in the
+// field tag.
+//
+// Because Unmarshal uses the reflect package, it can only assign
+// to exported (upper case) fields.  Unmarshal uses a case-insensitive
+// comparison to match XML element names to struct field names.
+//
+// Unmarshal maps an XML element to a struct using the following rules.
+// In the rules, the tag of a field refers to the value associated with the
+// key 'xml' in the struct field's tag (see the example above).
+//
+//   * If the struct has a field of type []byte or string with tag "innerxml",
+//      Unmarshal accumulates the raw XML nested inside the element
+//      in that field.  The rest of the rules still apply.
+//
+//   * If the struct has a field named XMLName of type xml.Name,
+//      Unmarshal records the element name in that field.
+//
+//   * If the XMLName field has an associated tag of the form
+//      "name" or "namespace-URL name", the XML element must have
+//      the given name (and, optionally, name space) or else Unmarshal
+//      returns an error.
+//
+//   * If the XML element has an attribute whose name matches a
+//      struct field of type string with tag "attr", Unmarshal records
+//      the attribute value in that field.
+//
+//   * If the XML element contains character data, that data is
+//      accumulated in the first struct field that has tag "chardata".
+//      The struct field may have type []byte or string.
+//      If there is no such field, the character data is discarded.
+//
+//   * If the XML element contains comments, they are accumulated in
+//      the first struct field that has tag "comments".  The struct
+//      field may have type []byte or string.  If there is no such
+//      field, the comments are discarded.
+//
+//   * If the XML element contains a sub-element whose name matches
+//      the prefix of a tag formatted as "a>b>c", unmarshal
+//      will descend into the XML structure looking for elements with the
+//      given names, and will map the innermost elements to that struct field.
+//      A tag starting with ">" is equivalent to one starting
+//      with the field name followed by ">".
+//
+//   * If the XML element contains a sub-element whose name
+//      matches a field whose tag is neither "attr" nor "chardata",
+//      Unmarshal maps the sub-element to that struct field.
+//      Otherwise, if the struct has a field named Any, unmarshal
+//      maps the sub-element to that struct field.
+//
+// Unmarshal maps an XML element to a string or []byte by saving the
+// concatenation of that element's character data in the string or
+// []byte.
+//
+// Unmarshal maps an attribute value to a string or []byte by saving
+// the value in the string or slice.
+//
+// Unmarshal maps an XML element to a slice by extending the length of
+// the slice and mapping the element to the newly created value.
+//
+// Unmarshal maps an XML element or attribute value to a bool by
+// setting it to the boolean value represented by the string.
+//
+// Unmarshal maps an XML element or attribute value to an integer or
+// floating-point field by setting the field to the result of
+// interpreting the string value in decimal.  There is no check for
+// overflow.
+//
+// Unmarshal maps an XML element to an xml.Name by recording the
+// element name.
+//
+// Unmarshal maps an XML element to a pointer by setting the pointer
+// to a freshly allocated value and then mapping the element to that value.
+//
+func Unmarshal(r io.Reader, val interface{}) error {
+	v := reflect.ValueOf(val)
+	if v.Kind() != reflect.Ptr {
+		return errors.New("non-pointer passed to Unmarshal")
+	}
+	p := NewParser(r)
+	elem := v.Elem()
+	err := p.unmarshal(elem, nil)
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+// An UnmarshalError represents an error in the unmarshalling process.
+type UnmarshalError string
+
+func (e UnmarshalError) Error() string { return string(e) }
+
+// A TagPathError represents an error in the unmarshalling process
+// caused by the use of field tags with conflicting paths.
+type TagPathError struct {
+	Struct       reflect.Type
+	Field1, Tag1 string
+	Field2, Tag2 string
+}
+
+func (e *TagPathError) Error() string {
+	return fmt.Sprintf("%s field %q with tag %q conflicts with field %q with tag %q", e.Struct, e.Field1, e.Tag1, e.Field2, e.Tag2)
+}
+
+// The Parser's Unmarshal method is like xml.Unmarshal
+// except that it can be passed a pointer to the initial start element,
+// useful when a client reads some raw XML tokens itself
+// but also defers to Unmarshal for some elements.
+// Passing a nil start element indicates that Unmarshal should
+// read the token stream to find the start element.
+func (p *Parser) Unmarshal(val interface{}, start *StartElement) error {
+	v := reflect.ValueOf(val)
+	if v.Kind() != reflect.Ptr {
+		return errors.New("non-pointer passed to Unmarshal")
+	}
+	return p.unmarshal(v.Elem(), start)
+}
+
+// fieldName strips invalid characters from an XML name
+// to create a valid Go struct name.  It also converts the
+// name to lower case letters.
+func fieldName(original string) string {
+
+	var i int
+	//remove leading underscores, without exhausting all characters
+	for i = 0; i < len(original)-1 && original[i] == '_'; i++ {
+	}
+
+	return strings.Map(
+		func(x rune) rune {
+			if x == '_' || unicode.IsDigit(x) || unicode.IsLetter(x) {
+				return unicode.ToLower(x)
+			}
+			return -1
+		},
+		original[i:])
+}
+
+// Unmarshal a single XML element into val.
+func (p *Parser) unmarshal(val reflect.Value, start *StartElement) error {
+	// Find start element if we need it.
+	if start == nil {
+		for {
+			tok, err := p.Token()
+			if err != nil {
+				return err
+			}
+			if t, ok := tok.(StartElement); ok {
+				start = &t
+				break
+			}
+		}
+	}
+
+	if pv := val; pv.Kind() == reflect.Ptr {
+		if pv.IsNil() {
+			pv.Set(reflect.New(pv.Type().Elem()))
+		}
+		val = pv.Elem()
+	}
+
+	var (
+		data         []byte
+		saveData     reflect.Value
+		comment      []byte
+		saveComment  reflect.Value
+		saveXML      reflect.Value
+		saveXMLIndex int
+		saveXMLData  []byte
+		sv           reflect.Value
+		styp         reflect.Type
+		fieldPaths   map[string]pathInfo
+	)
+
+	switch v := val; v.Kind() {
+	default:
+		return errors.New("unknown type " + v.Type().String())
+
+	case reflect.Slice:
+		typ := v.Type()
+		if typ.Elem().Kind() == reflect.Uint8 {
+			// []byte
+			saveData = v
+			break
+		}
+
+		// Slice of element values.
+		// Grow slice.
+		n := v.Len()
+		if n >= v.Cap() {
+			ncap := 2 * n
+			if ncap < 4 {
+				ncap = 4
+			}
+			new := reflect.MakeSlice(typ, n, ncap)
+			reflect.Copy(new, v)
+			v.Set(new)
+		}
+		v.SetLen(n + 1)
+
+		// Recur to read element into slice.
+		if err := p.unmarshal(v.Index(n), start); err != nil {
+			v.SetLen(n)
+			return err
+		}
+		return nil
+
+	case reflect.Bool, reflect.Float32, reflect.Float64, reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64, reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr, reflect.String:
+		saveData = v
+
+	case reflect.Struct:
+		if _, ok := v.Interface().(Name); ok {
+			v.Set(reflect.ValueOf(start.Name))
+			break
+		}
+
+		sv = v
+		typ := sv.Type()
+		styp = typ
+		// Assign name.
+		if f, ok := typ.FieldByName("XMLName"); ok {
+			// Validate element name.
+			if tag := f.Tag.Get("xml"); tag != "" {
+				ns := ""
+				i := strings.LastIndex(tag, " ")
+				if i >= 0 {
+					ns, tag = tag[0:i], tag[i+1:]
+				}
+				if tag != start.Name.Local {
+					return UnmarshalError("expected element type <" + tag + "> but have <" + start.Name.Local + ">")
+				}
+				if ns != "" && ns != start.Name.Space {
+					e := "expected element <" + tag + "> in name space " + ns + " but have "
+					if start.Name.Space == "" {
+						e += "no name space"
+					} else {
+						e += start.Name.Space
+					}
+					return UnmarshalError(e)
+				}
+			}
+
+			// Save
+			v := sv.FieldByIndex(f.Index)
+			if _, ok := v.Interface().(Name); ok {
+				v.Set(reflect.ValueOf(start.Name))
+			}
+		}
+
+		// Assign attributes.
+		// Also, determine whether we need to save character data or comments.
+		for i, n := 0, typ.NumField(); i < n; i++ {
+			f := typ.Field(i)
+			switch f.Tag.Get("xml") {
+			case "attr":
+				strv := sv.FieldByIndex(f.Index)
+				// Look for attribute.
+				val := ""
+				k := strings.ToLower(f.Name)
+				for _, a := range start.Attr {
+					if fieldName(a.Name.Local) == k {
+						val = a.Value
+						break
+					}
+				}
+				copyValue(strv, []byte(val))
+
+			case "comment":
+				if !saveComment.IsValid() {
+					saveComment = sv.FieldByIndex(f.Index)
+				}
+
+			case "chardata":
+				if !saveData.IsValid() {
+					saveData = sv.FieldByIndex(f.Index)
+				}
+
+			case "innerxml":
+				if !saveXML.IsValid() {
+					saveXML = sv.FieldByIndex(f.Index)
+					if p.saved == nil {
+						saveXMLIndex = 0
+						p.saved = new(bytes.Buffer)
+					} else {
+						saveXMLIndex = p.savedOffset()
+					}
+				}
+
+			default:
+				if tag := f.Tag.Get("xml"); strings.Contains(tag, ">") {
+					if fieldPaths == nil {
+						fieldPaths = make(map[string]pathInfo)
+					}
+					path := strings.ToLower(tag)
+					if strings.HasPrefix(tag, ">") {
+						path = strings.ToLower(f.Name) + path
+					}
+					if strings.HasSuffix(tag, ">") {
+						path = path[:len(path)-1]
+					}
+					err := addFieldPath(sv, fieldPaths, path, f.Index)
+					if err != nil {
+						return err
+					}
+				}
+			}
+		}
+	}
+
+	// Find end element.
+	// Process sub-elements along the way.
+Loop:
+	for {
+		var savedOffset int
+		if saveXML.IsValid() {
+			savedOffset = p.savedOffset()
+		}
+		tok, err := p.Token()
+		if err != nil {
+			return err
+		}
+		switch t := tok.(type) {
+		case StartElement:
+			// Sub-element.
+			// Look up by tag name.
+			if sv.IsValid() {
+				k := fieldName(t.Name.Local)
+
+				if fieldPaths != nil {
+					if _, found := fieldPaths[k]; found {
+						if err := p.unmarshalPaths(sv, fieldPaths, k, &t); err != nil {
+							return err
+						}
+						continue Loop
+					}
+				}
+
+				match := func(s string) bool {
+					// check if the name matches ignoring case
+					if strings.ToLower(s) != k {
+						return false
+					}
+					// now check that it's public
+					c, _ := utf8.DecodeRuneInString(s)
+					return unicode.IsUpper(c)
+				}
+
+				f, found := styp.FieldByNameFunc(match)
+				if !found { // fall back to mop-up field named "Any"
+					f, found = styp.FieldByName("Any")
+				}
+				if found {
+					if err := p.unmarshal(sv.FieldByIndex(f.Index), &t); err != nil {
+						return err
+					}
+					continue Loop
+				}
+			}
+			// Not saving sub-element but still have to skip over it.
+			if err := p.Skip(); err != nil {
+				return err
+			}
+
+		case EndElement:
+			if saveXML.IsValid() {
+				saveXMLData = p.saved.Bytes()[saveXMLIndex:savedOffset]
+				if saveXMLIndex == 0 {
+					p.saved = nil
+				}
+			}
+			break Loop
+
+		case CharData:
+			if saveData.IsValid() {
+				data = append(data, t...)
+			}
+
+		case Comment:
+			if saveComment.IsValid() {
+				comment = append(comment, t...)
+			}
+		}
+	}
+
+	if err := copyValue(saveData, data); err != nil {
+		return err
+	}
+
+	switch t := saveComment; t.Kind() {
+	case reflect.String:
+		t.SetString(string(comment))
+	case reflect.Slice:
+		t.Set(reflect.ValueOf(comment))
+	}
+
+	switch t := saveXML; t.Kind() {
+	case reflect.String:
+		t.SetString(string(saveXMLData))
+	case reflect.Slice:
+		t.Set(reflect.ValueOf(saveXMLData))
+	}
+
+	return nil
+}
+
+func copyValue(dst reflect.Value, src []byte) (err error) {
+	// Helper functions for integer and unsigned integer conversions
+	var itmp int64
+	getInt64 := func() bool {
+		itmp, err = strconv.Atoi64(string(src))
+		// TODO: should check sizes
+		return err == nil
+	}
+	var utmp uint64
+	getUint64 := func() bool {
+		utmp, err = strconv.Atoui64(string(src))
+		// TODO: check for overflow?
+		return err == nil
+	}
+	var ftmp float64
+	getFloat64 := func() bool {
+		ftmp, err = strconv.Atof64(string(src))
+		// TODO: check for overflow?
+		return err == nil
+	}
+
+	// Save accumulated data and comments
+	switch t := dst; t.Kind() {
+	case reflect.Invalid:
+		// Probably a comment, handled below
+	default:
+		return errors.New("cannot happen: unknown type " + t.Type().String())
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		if !getInt64() {
+			return err
+		}
+		t.SetInt(itmp)
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+		if !getUint64() {
+			return err
+		}
+		t.SetUint(utmp)
+	case reflect.Float32, reflect.Float64:
+		if !getFloat64() {
+			return err
+		}
+		t.SetFloat(ftmp)
+	case reflect.Bool:
+		value, err := strconv.Atob(strings.TrimSpace(string(src)))
+		if err != nil {
+			return err
+		}
+		t.SetBool(value)
+	case reflect.String:
+		t.SetString(string(src))
+	case reflect.Slice:
+		t.Set(reflect.ValueOf(src))
+	}
+	return nil
+}
+
+type pathInfo struct {
+	fieldIdx []int
+	complete bool
+}
+
+// addFieldPath takes an element path such as "a>b>c" and fills the
+// paths map with all paths leading to it ("a", "a>b", and "a>b>c").
+// It is okay for paths to share a common, shorter prefix but not ok
+// for one path to itself be a prefix of another.
+func addFieldPath(sv reflect.Value, paths map[string]pathInfo, path string, fieldIdx []int) error {
+	if info, found := paths[path]; found {
+		return tagError(sv, info.fieldIdx, fieldIdx)
+	}
+	paths[path] = pathInfo{fieldIdx, true}
+	for {
+		i := strings.LastIndex(path, ">")
+		if i < 0 {
+			break
+		}
+		path = path[:i]
+		if info, found := paths[path]; found {
+			if info.complete {
+				return tagError(sv, info.fieldIdx, fieldIdx)
+			}
+		} else {
+			paths[path] = pathInfo{fieldIdx, false}
+		}
+	}
+	return nil
+
+}
+
+func tagError(sv reflect.Value, idx1 []int, idx2 []int) error {
+	t := sv.Type()
+	f1 := t.FieldByIndex(idx1)
+	f2 := t.FieldByIndex(idx2)
+	return &TagPathError{t, f1.Name, f1.Tag.Get("xml"), f2.Name, f2.Tag.Get("xml")}
+}
+
+// unmarshalPaths walks down an XML structure looking for
+// wanted paths, and calls unmarshal on them.
+func (p *Parser) unmarshalPaths(sv reflect.Value, paths map[string]pathInfo, path string, start *StartElement) error {
+	if info, _ := paths[path]; info.complete {
+		return p.unmarshal(sv.FieldByIndex(info.fieldIdx), start)
+	}
+	for {
+		tok, err := p.Token()
+		if err != nil {
+			return err
+		}
+		switch t := tok.(type) {
+		case StartElement:
+			k := path + ">" + fieldName(t.Name.Local)
+			if _, found := paths[k]; found {
+				if err := p.unmarshalPaths(sv, paths, k, &t); err != nil {
+					return err
+				}
+				continue
+			}
+			if err := p.Skip(); err != nil {
+				return err
+			}
+		case EndElement:
+			return nil
+		}
+	}
+	panic("unreachable")
+}
+
+// Have already read a start element.
+// Read tokens until we find the end element.
+// Token is taking care of making sure the
+// end element matches the start element we saw.
+func (p *Parser) Skip() error {
+	for {
+		tok, err := p.Token()
+		if err != nil {
+			return err
+		}
+		switch tok.(type) {
+		case StartElement:
+			if err := p.Skip(); err != nil {
+				return err
+			}
+		case EndElement:
+			return nil
+		}
+	}
+	panic("unreachable")
+}
diff --git a/libgo/go/encoding/xml/read_test.go b/libgo/go/encoding/xml/read_test.go
new file mode 100644
index 00000000000..fbb7fd5d2f2
--- /dev/null
+++ b/libgo/go/encoding/xml/read_test.go
@@ -0,0 +1,402 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package xml
+
+import (
+	"reflect"
+	"testing"
+)
+
+// Stripped down Atom feed data structures.
+
+func TestUnmarshalFeed(t *testing.T) {
+	var f Feed
+	if err := Unmarshal(StringReader(atomFeedString), &f); err != nil {
+		t.Fatalf("Unmarshal: %s", err)
+	}
+	if !reflect.DeepEqual(f, atomFeed) {
+		t.Fatalf("have %#v\nwant %#v", f, atomFeed)
+	}
+}
+
+// hget http://codereview.appspot.com/rss/mine/rsc
+const atomFeedString = `
+<?xml version="1.0" encoding="utf-8"?>
+<feed xmlns="http://www.w3.org/2005/Atom" xml:lang="en-us"><title>Code Review - My issues</title><link href="http://codereview.appspot.com/" rel="alternate"></link><li-nk href="http://codereview.appspot.com/rss/mine/rsc" rel="self"></li-nk><id>http://codereview.appspot.com/</id><updated>2009-10-04T01:35:58+00:00</updated><author><name>rietveld&lt;&gt;</name></author><entry><title>rietveld: an attempt at pubsubhubbub
+</title><link hre-f="http://codereview.appspot.com/126085" rel="alternate"></link><updated>2009-10-04T01:35:58+00:00</updated><author><name>email-address-removed</name></author><id>urn:md5:134d9179c41f806be79b3a5f7877d19a</id><summary type="html">
+  An attempt at adding pubsubhubbub support to Rietveld.
+http://code.google.com/p/pubsubhubbub
+http://code.google.com/p/rietveld/issues/detail?id=155
+
+The server side of the protocol is trivial:
+  1. add a &amp;lt;link rel=&amp;quot;hub&amp;quot; href=&amp;quot;hub-server&amp;quot;&amp;gt; tag to all
+     feeds that will be pubsubhubbubbed.
+  2. every time one of those feeds changes, tell the hub
+     with a simple POST request.
+
+I have tested this by adding debug prints to a local hub
+server and checking that the server got the right publish
+requests.
+
+I can&amp;#39;t quite get the server to work, but I think the bug
+is not in my code.  I think that the server expects to be
+able to grab the feed and see the feed&amp;#39;s actual URL in
+the link rel=&amp;quot;self&amp;quot;, but the default value for that drops
+the :port from the URL, and I cannot for the life of me
+figure out how to get the Atom generator deep inside
+django not to do that, or even where it is doing that,
+or even what code is running to generate the Atom feed.
+(I thought I knew but I added some assert False statements
+and it kept running!)
+
+Ignoring that particular problem, I would appreciate
+feedback on the right way to get the two values at
+the top of feeds.py marked NOTE(rsc).
+
+
+</summary></entry><entry><title>rietveld: correct tab handling
+</title><link href="http://codereview.appspot.com/124106" rel="alternate"></link><updated>2009-10-03T23:02:17+00:00</updated><author><name>email-address-removed</name></author><id>urn:md5:0a2a4f19bb815101f0ba2904aed7c35a</id><summary type="html">
+  This fixes the buggy tab rendering that can be seen at
+http://codereview.appspot.com/116075/diff/1/2
+
+The fundamental problem was that the tab code was
+not being told what column the text began in, so it
+didn&amp;#39;t know where to put the tab stops.  Another problem
+was that some of the code assumed that string byte
+offsets were the same as column offsets, which is only
+true if there are no tabs.
+
+In the process of fixing this, I cleaned up the arguments
+to Fold and ExpandTabs and renamed them Break and
+_ExpandTabs so that I could be sure that I found all the
+call sites.  I also wanted to verify that ExpandTabs was
+not being used from outside intra_region_diff.py.
+
+
+</summary></entry></feed> 	   `
+
+type Feed struct {
+	XMLName Name `xml:"http://www.w3.org/2005/Atom feed"`
+	Title   string
+	Id      string
+	Link    []Link
+	Updated Time
+	Author  Person
+	Entry   []Entry
+}
+
+type Entry struct {
+	Title   string
+	Id      string
+	Link    []Link
+	Updated Time
+	Author  Person
+	Summary Text
+}
+
+type Link struct {
+	Rel  string `xml:"attr"`
+	Href string `xml:"attr"`
+}
+
+type Person struct {
+	Name     string
+	URI      string
+	Email    string
+	InnerXML string `xml:"innerxml"`
+}
+
+type Text struct {
+	Type string `xml:"attr"`
+	Body string `xml:"chardata"`
+}
+
+type Time string
+
+var atomFeed = Feed{
+	XMLName: Name{"http://www.w3.org/2005/Atom", "feed"},
+	Title:   "Code Review - My issues",
+	Link: []Link{
+		{Rel: "alternate", Href: "http://codereview.appspot.com/"},
+		{Rel: "self", Href: "http://codereview.appspot.com/rss/mine/rsc"},
+	},
+	Id:      "http://codereview.appspot.com/",
+	Updated: "2009-10-04T01:35:58+00:00",
+	Author: Person{
+		Name:     "rietveld<>",
+		InnerXML: "<name>rietveld&lt;&gt;</name>",
+	},
+	Entry: []Entry{
+		{
+			Title: "rietveld: an attempt at pubsubhubbub\n",
+			Link: []Link{
+				{Rel: "alternate", Href: "http://codereview.appspot.com/126085"},
+			},
+			Updated: "2009-10-04T01:35:58+00:00",
+			Author: Person{
+				Name:     "email-address-removed",
+				InnerXML: "<name>email-address-removed</name>",
+			},
+			Id: "urn:md5:134d9179c41f806be79b3a5f7877d19a",
+			Summary: Text{
+				Type: "html",
+				Body: `
+  An attempt at adding pubsubhubbub support to Rietveld.
+http://code.google.com/p/pubsubhubbub
+http://code.google.com/p/rietveld/issues/detail?id=155
+
+The server side of the protocol is trivial:
+  1. add a &lt;link rel=&quot;hub&quot; href=&quot;hub-server&quot;&gt; tag to all
+     feeds that will be pubsubhubbubbed.
+  2. every time one of those feeds changes, tell the hub
+     with a simple POST request.
+
+I have tested this by adding debug prints to a local hub
+server and checking that the server got the right publish
+requests.
+
+I can&#39;t quite get the server to work, but I think the bug
+is not in my code.  I think that the server expects to be
+able to grab the feed and see the feed&#39;s actual URL in
+the link rel=&quot;self&quot;, but the default value for that drops
+the :port from the URL, and I cannot for the life of me
+figure out how to get the Atom generator deep inside
+django not to do that, or even where it is doing that,
+or even what code is running to generate the Atom feed.
+(I thought I knew but I added some assert False statements
+and it kept running!)
+
+Ignoring that particular problem, I would appreciate
+feedback on the right way to get the two values at
+the top of feeds.py marked NOTE(rsc).
+
+
+`,
+			},
+		},
+		{
+			Title: "rietveld: correct tab handling\n",
+			Link: []Link{
+				{Rel: "alternate", Href: "http://codereview.appspot.com/124106"},
+			},
+			Updated: "2009-10-03T23:02:17+00:00",
+			Author: Person{
+				Name:     "email-address-removed",
+				InnerXML: "<name>email-address-removed</name>",
+			},
+			Id: "urn:md5:0a2a4f19bb815101f0ba2904aed7c35a",
+			Summary: Text{
+				Type: "html",
+				Body: `
+  This fixes the buggy tab rendering that can be seen at
+http://codereview.appspot.com/116075/diff/1/2
+
+The fundamental problem was that the tab code was
+not being told what column the text began in, so it
+didn&#39;t know where to put the tab stops.  Another problem
+was that some of the code assumed that string byte
+offsets were the same as column offsets, which is only
+true if there are no tabs.
+
+In the process of fixing this, I cleaned up the arguments
+to Fold and ExpandTabs and renamed them Break and
+_ExpandTabs so that I could be sure that I found all the
+call sites.  I also wanted to verify that ExpandTabs was
+not being used from outside intra_region_diff.py.
+
+
+`,
+			},
+		},
+	},
+}
+
+type FieldNameTest struct {
+	in, out string
+}
+
+var FieldNameTests = []FieldNameTest{
+	{"Profile-Image", "profileimage"},
+	{"_score", "score"},
+}
+
+func TestFieldName(t *testing.T) {
+	for _, tt := range FieldNameTests {
+		a := fieldName(tt.in)
+		if a != tt.out {
+			t.Fatalf("have %#v\nwant %#v\n\n", a, tt.out)
+		}
+	}
+}
+
+const pathTestString = `
+<result>
+    <before>1</before>
+    <items>
+        <item1>
+            <value>A</value>
+        </item1>
+        <item2>
+            <value>B</value>
+        </item2>
+        <Item1>
+            <Value>C</Value>
+            <Value>D</Value>
+        </Item1>
+        <_>
+            <value>E</value>
+        </_>
+    </items>
+    <after>2</after>
+</result>
+`
+
+type PathTestItem struct {
+	Value string
+}
+
+type PathTestA struct {
+	Items         []PathTestItem `xml:">item1"`
+	Before, After string
+}
+
+type PathTestB struct {
+	Other         []PathTestItem `xml:"items>Item1"`
+	Before, After string
+}
+
+type PathTestC struct {
+	Values1       []string `xml:"items>item1>value"`
+	Values2       []string `xml:"items>item2>value"`
+	Before, After string
+}
+
+type PathTestSet struct {
+	Item1 []PathTestItem
+}
+
+type PathTestD struct {
+	Other         PathTestSet `xml:"items>"`
+	Before, After string
+}
+
+type PathTestE struct {
+	Underline     string `xml:"items>_>value"`
+	Before, After string
+}
+
+var pathTests = []interface{}{
+	&PathTestA{Items: []PathTestItem{{"A"}, {"D"}}, Before: "1", After: "2"},
+	&PathTestB{Other: []PathTestItem{{"A"}, {"D"}}, Before: "1", After: "2"},
+	&PathTestC{Values1: []string{"A", "C", "D"}, Values2: []string{"B"}, Before: "1", After: "2"},
+	&PathTestD{Other: PathTestSet{Item1: []PathTestItem{{"A"}, {"D"}}}, Before: "1", After: "2"},
+	&PathTestE{Underline: "E", Before: "1", After: "2"},
+}
+
+func TestUnmarshalPaths(t *testing.T) {
+	for _, pt := range pathTests {
+		v := reflect.New(reflect.TypeOf(pt).Elem()).Interface()
+		if err := Unmarshal(StringReader(pathTestString), v); err != nil {
+			t.Fatalf("Unmarshal: %s", err)
+		}
+		if !reflect.DeepEqual(v, pt) {
+			t.Fatalf("have %#v\nwant %#v", v, pt)
+		}
+	}
+}
+
+type BadPathTestA struct {
+	First  string `xml:"items>item1"`
+	Other  string `xml:"items>item2"`
+	Second string `xml:"items>"`
+}
+
+type BadPathTestB struct {
+	Other  string `xml:"items>item2>value"`
+	First  string `xml:"items>item1"`
+	Second string `xml:"items>item1>value"`
+}
+
+var badPathTests = []struct {
+	v, e interface{}
+}{
+	{&BadPathTestA{}, &TagPathError{reflect.TypeOf(BadPathTestA{}), "First", "items>item1", "Second", "items>"}},
+	{&BadPathTestB{}, &TagPathError{reflect.TypeOf(BadPathTestB{}), "First", "items>item1", "Second", "items>item1>value"}},
+}
+
+func TestUnmarshalBadPaths(t *testing.T) {
+	for _, tt := range badPathTests {
+		err := Unmarshal(StringReader(pathTestString), tt.v)
+		if !reflect.DeepEqual(err, tt.e) {
+			t.Fatalf("Unmarshal with %#v didn't fail properly: %#v", tt.v, err)
+		}
+	}
+}
+
+func TestUnmarshalAttrs(t *testing.T) {
+	var f AttrTest
+	if err := Unmarshal(StringReader(attrString), &f); err != nil {
+		t.Fatalf("Unmarshal: %s", err)
+	}
+	if !reflect.DeepEqual(f, attrStruct) {
+		t.Fatalf("have %#v\nwant %#v", f, attrStruct)
+	}
+}
+
+type AttrTest struct {
+	Test1 Test1
+	Test2 Test2
+}
+
+type Test1 struct {
+	Int   int     `xml:"attr"`
+	Float float64 `xml:"attr"`
+	Uint8 uint8   `xml:"attr"`
+}
+
+type Test2 struct {
+	Bool bool `xml:"attr"`
+}
+
+const attrString = `
+<?xml version="1.0" charset="utf-8"?>
+<attrtest>
+  <test1 int="8" float="23.5" uint8="255"/>
+  <test2 bool="true"/>
+</attrtest>
+`
+
+var attrStruct = AttrTest{
+	Test1: Test1{
+		Int:   8,
+		Float: 23.5,
+		Uint8: 255,
+	},
+	Test2: Test2{
+		Bool: true,
+	},
+}
+
+// test data for TestUnmarshalWithoutNameType
+
+const OK = "OK"
+const withoutNameTypeData = `
+<?xml version="1.0" charset="utf-8"?>
+<Test3 attr="OK" />`
+
+type TestThree struct {
+	XMLName bool   `xml:"Test3"` // XMLName field without an xml.Name type 
+	Attr    string `xml:"attr"`
+}
+
+func TestUnmarshalWithoutNameType(t *testing.T) {
+	var x TestThree
+	if err := Unmarshal(StringReader(withoutNameTypeData), &x); err != nil {
+		t.Fatalf("Unmarshal: %s", err)
+	}
+	if x.Attr != OK {
+		t.Fatalf("have %v\nwant %v", x.Attr, OK)
+	}
+}
diff --git a/libgo/go/encoding/xml/xml.go b/libgo/go/encoding/xml/xml.go
new file mode 100644
index 00000000000..216d8889b23
--- /dev/null
+++ b/libgo/go/encoding/xml/xml.go
@@ -0,0 +1,1697 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package xml implements a simple XML 1.0 parser that
+// understands XML name spaces.
+package xml
+
+// References:
+//    Annotated XML spec: http://www.xml.com/axml/testaxml.htm
+//    XML name spaces: http://www.w3.org/TR/REC-xml-names/
+
+// TODO(rsc):
+//	Test error handling.
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"io"
+	"strconv"
+	"strings"
+	"unicode"
+	"unicode/utf8"
+)
+
+// A SyntaxError represents a syntax error in the XML input stream.
+type SyntaxError struct {
+	Msg  string
+	Line int
+}
+
+func (e *SyntaxError) Error() string {
+	return "XML syntax error on line " + strconv.Itoa(e.Line) + ": " + e.Msg
+}
+
+// A Name represents an XML name (Local) annotated
+// with a name space identifier (Space).
+// In tokens returned by Parser.Token, the Space identifier
+// is given as a canonical URL, not the short prefix used
+// in the document being parsed.
+type Name struct {
+	Space, Local string
+}
+
+// An Attr represents an attribute in an XML element (Name=Value).
+type Attr struct {
+	Name  Name
+	Value string
+}
+
+// A Token is an interface holding one of the token types:
+// StartElement, EndElement, CharData, Comment, ProcInst, or Directive.
+type Token interface{}
+
+// A StartElement represents an XML start element.
+type StartElement struct {
+	Name Name
+	Attr []Attr
+}
+
+func (e StartElement) Copy() StartElement {
+	attrs := make([]Attr, len(e.Attr))
+	copy(e.Attr, attrs)
+	e.Attr = attrs
+	return e
+}
+
+// An EndElement represents an XML end element.
+type EndElement struct {
+	Name Name
+}
+
+// A CharData represents XML character data (raw text),
+// in which XML escape sequences have been replaced by
+// the characters they represent.
+type CharData []byte
+
+func makeCopy(b []byte) []byte {
+	b1 := make([]byte, len(b))
+	copy(b1, b)
+	return b1
+}
+
+func (c CharData) Copy() CharData { return CharData(makeCopy(c)) }
+
+// A Comment represents an XML comment of the form <!--comment-->.
+// The bytes do not include the <!-- and --> comment markers.
+type Comment []byte
+
+func (c Comment) Copy() Comment { return Comment(makeCopy(c)) }
+
+// A ProcInst represents an XML processing instruction of the form <?target inst?>
+type ProcInst struct {
+	Target string
+	Inst   []byte
+}
+
+func (p ProcInst) Copy() ProcInst {
+	p.Inst = makeCopy(p.Inst)
+	return p
+}
+
+// A Directive represents an XML directive of the form <!text>.
+// The bytes do not include the <! and > markers.
+type Directive []byte
+
+func (d Directive) Copy() Directive { return Directive(makeCopy(d)) }
+
+// CopyToken returns a copy of a Token.
+func CopyToken(t Token) Token {
+	switch v := t.(type) {
+	case CharData:
+		return v.Copy()
+	case Comment:
+		return v.Copy()
+	case Directive:
+		return v.Copy()
+	case ProcInst:
+		return v.Copy()
+	case StartElement:
+		return v.Copy()
+	}
+	return t
+}
+
+// A Parser represents an XML parser reading a particular input stream.
+// The parser assumes that its input is encoded in UTF-8.
+type Parser struct {
+	// Strict defaults to true, enforcing the requirements
+	// of the XML specification.
+	// If set to false, the parser allows input containing common
+	// mistakes:
+	//	* If an element is missing an end tag, the parser invents
+	//	  end tags as necessary to keep the return values from Token
+	//	  properly balanced.
+	//	* In attribute values and character data, unknown or malformed
+	//	  character entities (sequences beginning with &) are left alone.
+	//
+	// Setting:
+	//
+	//	p.Strict = false;
+	//	p.AutoClose = HTMLAutoClose;
+	//	p.Entity = HTMLEntity
+	//
+	// creates a parser that can handle typical HTML.
+	Strict bool
+
+	// When Strict == false, AutoClose indicates a set of elements to
+	// consider closed immediately after they are opened, regardless
+	// of whether an end element is present.
+	AutoClose []string
+
+	// Entity can be used to map non-standard entity names to string replacements.
+	// The parser behaves as if these standard mappings are present in the map,
+	// regardless of the actual map content:
+	//
+	//	"lt": "<",
+	//	"gt": ">",
+	//	"amp": "&",
+	//	"apos": "'",
+	//	"quot": `"`,
+	Entity map[string]string
+
+	// CharsetReader, if non-nil, defines a function to generate
+	// charset-conversion readers, converting from the provided
+	// non-UTF-8 charset into UTF-8. If CharsetReader is nil or
+	// returns an error, parsing stops with an error. One of the
+	// the CharsetReader's result values must be non-nil.
+	CharsetReader func(charset string, input io.Reader) (io.Reader, error)
+
+	r         io.ByteReader
+	buf       bytes.Buffer
+	saved     *bytes.Buffer
+	stk       *stack
+	free      *stack
+	needClose bool
+	toClose   Name
+	nextToken Token
+	nextByte  int
+	ns        map[string]string
+	err       error
+	line      int
+	tmp       [32]byte
+}
+
+// NewParser creates a new XML parser reading from r.
+func NewParser(r io.Reader) *Parser {
+	p := &Parser{
+		ns:       make(map[string]string),
+		nextByte: -1,
+		line:     1,
+		Strict:   true,
+	}
+	p.switchToReader(r)
+	return p
+}
+
+// Token returns the next XML token in the input stream.
+// At the end of the input stream, Token returns nil, io.EOF.
+//
+// Slices of bytes in the returned token data refer to the
+// parser's internal buffer and remain valid only until the next
+// call to Token.  To acquire a copy of the bytes, call CopyToken
+// or the token's Copy method.
+//
+// Token expands self-closing elements such as <br/>
+// into separate start and end elements returned by successive calls.
+//
+// Token guarantees that the StartElement and EndElement
+// tokens it returns are properly nested and matched:
+// if Token encounters an unexpected end element,
+// it will return an error.
+//
+// Token implements XML name spaces as described by
+// http://www.w3.org/TR/REC-xml-names/.  Each of the
+// Name structures contained in the Token has the Space
+// set to the URL identifying its name space when known.
+// If Token encounters an unrecognized name space prefix,
+// it uses the prefix as the Space rather than report an error.
+func (p *Parser) Token() (t Token, err error) {
+	if p.nextToken != nil {
+		t = p.nextToken
+		p.nextToken = nil
+	} else if t, err = p.RawToken(); err != nil {
+		return
+	}
+
+	if !p.Strict {
+		if t1, ok := p.autoClose(t); ok {
+			p.nextToken = t
+			t = t1
+		}
+	}
+	switch t1 := t.(type) {
+	case StartElement:
+		// In XML name spaces, the translations listed in the
+		// attributes apply to the element name and
+		// to the other attribute names, so process
+		// the translations first.
+		for _, a := range t1.Attr {
+			if a.Name.Space == "xmlns" {
+				v, ok := p.ns[a.Name.Local]
+				p.pushNs(a.Name.Local, v, ok)
+				p.ns[a.Name.Local] = a.Value
+			}
+			if a.Name.Space == "" && a.Name.Local == "xmlns" {
+				// Default space for untagged names
+				v, ok := p.ns[""]
+				p.pushNs("", v, ok)
+				p.ns[""] = a.Value
+			}
+		}
+
+		p.translate(&t1.Name, true)
+		for i := range t1.Attr {
+			p.translate(&t1.Attr[i].Name, false)
+		}
+		p.pushElement(t1.Name)
+		t = t1
+
+	case EndElement:
+		p.translate(&t1.Name, true)
+		if !p.popElement(&t1) {
+			return nil, p.err
+		}
+		t = t1
+	}
+	return
+}
+
+// Apply name space translation to name n.
+// The default name space (for Space=="")
+// applies only to element names, not to attribute names.
+func (p *Parser) translate(n *Name, isElementName bool) {
+	switch {
+	case n.Space == "xmlns":
+		return
+	case n.Space == "" && !isElementName:
+		return
+	case n.Space == "" && n.Local == "xmlns":
+		return
+	}
+	if v, ok := p.ns[n.Space]; ok {
+		n.Space = v
+	}
+}
+
+func (p *Parser) switchToReader(r io.Reader) {
+	// Get efficient byte at a time reader.
+	// Assume that if reader has its own
+	// ReadByte, it's efficient enough.
+	// Otherwise, use bufio.
+	if rb, ok := r.(io.ByteReader); ok {
+		p.r = rb
+	} else {
+		p.r = bufio.NewReader(r)
+	}
+}
+
+// Parsing state - stack holds old name space translations
+// and the current set of open elements.  The translations to pop when
+// ending a given tag are *below* it on the stack, which is
+// more work but forced on us by XML.
+type stack struct {
+	next *stack
+	kind int
+	name Name
+	ok   bool
+}
+
+const (
+	stkStart = iota
+	stkNs
+)
+
+func (p *Parser) push(kind int) *stack {
+	s := p.free
+	if s != nil {
+		p.free = s.next
+	} else {
+		s = new(stack)
+	}
+	s.next = p.stk
+	s.kind = kind
+	p.stk = s
+	return s
+}
+
+func (p *Parser) pop() *stack {
+	s := p.stk
+	if s != nil {
+		p.stk = s.next
+		s.next = p.free
+		p.free = s
+	}
+	return s
+}
+
+// Record that we are starting an element with the given name.
+func (p *Parser) pushElement(name Name) {
+	s := p.push(stkStart)
+	s.name = name
+}
+
+// Record that we are changing the value of ns[local].
+// The old value is url, ok.
+func (p *Parser) pushNs(local string, url string, ok bool) {
+	s := p.push(stkNs)
+	s.name.Local = local
+	s.name.Space = url
+	s.ok = ok
+}
+
+// Creates a SyntaxError with the current line number.
+func (p *Parser) syntaxError(msg string) error {
+	return &SyntaxError{Msg: msg, Line: p.line}
+}
+
+// Record that we are ending an element with the given name.
+// The name must match the record at the top of the stack,
+// which must be a pushElement record.
+// After popping the element, apply any undo records from
+// the stack to restore the name translations that existed
+// before we saw this element.
+func (p *Parser) popElement(t *EndElement) bool {
+	s := p.pop()
+	name := t.Name
+	switch {
+	case s == nil || s.kind != stkStart:
+		p.err = p.syntaxError("unexpected end element </" + name.Local + ">")
+		return false
+	case s.name.Local != name.Local:
+		if !p.Strict {
+			p.needClose = true
+			p.toClose = t.Name
+			t.Name = s.name
+			return true
+		}
+		p.err = p.syntaxError("element <" + s.name.Local + "> closed by </" + name.Local + ">")
+		return false
+	case s.name.Space != name.Space:
+		p.err = p.syntaxError("element <" + s.name.Local + "> in space " + s.name.Space +
+			"closed by </" + name.Local + "> in space " + name.Space)
+		return false
+	}
+
+	// Pop stack until a Start is on the top, undoing the
+	// translations that were associated with the element we just closed.
+	for p.stk != nil && p.stk.kind != stkStart {
+		s := p.pop()
+		if s.ok {
+			p.ns[s.name.Local] = s.name.Space
+		} else {
+			delete(p.ns, s.name.Local)
+		}
+	}
+
+	return true
+}
+
+// If the top element on the stack is autoclosing and
+// t is not the end tag, invent the end tag.
+func (p *Parser) autoClose(t Token) (Token, bool) {
+	if p.stk == nil || p.stk.kind != stkStart {
+		return nil, false
+	}
+	name := strings.ToLower(p.stk.name.Local)
+	for _, s := range p.AutoClose {
+		if strings.ToLower(s) == name {
+			// This one should be auto closed if t doesn't close it.
+			et, ok := t.(EndElement)
+			if !ok || et.Name.Local != name {
+				return EndElement{p.stk.name}, true
+			}
+			break
+		}
+	}
+	return nil, false
+}
+
+// RawToken is like Token but does not verify that
+// start and end elements match and does not translate
+// name space prefixes to their corresponding URLs.
+func (p *Parser) RawToken() (Token, error) {
+	if p.err != nil {
+		return nil, p.err
+	}
+	if p.needClose {
+		// The last element we read was self-closing and
+		// we returned just the StartElement half.
+		// Return the EndElement half now.
+		p.needClose = false
+		return EndElement{p.toClose}, nil
+	}
+
+	b, ok := p.getc()
+	if !ok {
+		return nil, p.err
+	}
+
+	if b != '<' {
+		// Text section.
+		p.ungetc(b)
+		data := p.text(-1, false)
+		if data == nil {
+			return nil, p.err
+		}
+		return CharData(data), nil
+	}
+
+	if b, ok = p.mustgetc(); !ok {
+		return nil, p.err
+	}
+	switch b {
+	case '/':
+		// </: End element
+		var name Name
+		if name, ok = p.nsname(); !ok {
+			if p.err == nil {
+				p.err = p.syntaxError("expected element name after </")
+			}
+			return nil, p.err
+		}
+		p.space()
+		if b, ok = p.mustgetc(); !ok {
+			return nil, p.err
+		}
+		if b != '>' {
+			p.err = p.syntaxError("invalid characters between </" + name.Local + " and >")
+			return nil, p.err
+		}
+		return EndElement{name}, nil
+
+	case '?':
+		// <?: Processing instruction.
+		// TODO(rsc): Should parse the <?xml declaration to make sure
+		// the version is 1.0 and the encoding is UTF-8.
+		var target string
+		if target, ok = p.name(); !ok {
+			if p.err == nil {
+				p.err = p.syntaxError("expected target name after <?")
+			}
+			return nil, p.err
+		}
+		p.space()
+		p.buf.Reset()
+		var b0 byte
+		for {
+			if b, ok = p.mustgetc(); !ok {
+				return nil, p.err
+			}
+			p.buf.WriteByte(b)
+			if b0 == '?' && b == '>' {
+				break
+			}
+			b0 = b
+		}
+		data := p.buf.Bytes()
+		data = data[0 : len(data)-2] // chop ?>
+
+		if target == "xml" {
+			enc := procInstEncoding(string(data))
+			if enc != "" && enc != "utf-8" && enc != "UTF-8" {
+				if p.CharsetReader == nil {
+					p.err = fmt.Errorf("xml: encoding %q declared but Parser.CharsetReader is nil", enc)
+					return nil, p.err
+				}
+				newr, err := p.CharsetReader(enc, p.r.(io.Reader))
+				if err != nil {
+					p.err = fmt.Errorf("xml: opening charset %q: %v", enc, err)
+					return nil, p.err
+				}
+				if newr == nil {
+					panic("CharsetReader returned a nil Reader for charset " + enc)
+				}
+				p.switchToReader(newr)
+			}
+		}
+		return ProcInst{target, data}, nil
+
+	case '!':
+		// <!: Maybe comment, maybe CDATA.
+		if b, ok = p.mustgetc(); !ok {
+			return nil, p.err
+		}
+		switch b {
+		case '-': // <!-
+			// Probably <!-- for a comment.
+			if b, ok = p.mustgetc(); !ok {
+				return nil, p.err
+			}
+			if b != '-' {
+				p.err = p.syntaxError("invalid sequence <!- not part of <!--")
+				return nil, p.err
+			}
+			// Look for terminator.
+			p.buf.Reset()
+			var b0, b1 byte
+			for {
+				if b, ok = p.mustgetc(); !ok {
+					return nil, p.err
+				}
+				p.buf.WriteByte(b)
+				if b0 == '-' && b1 == '-' && b == '>' {
+					break
+				}
+				b0, b1 = b1, b
+			}
+			data := p.buf.Bytes()
+			data = data[0 : len(data)-3] // chop -->
+			return Comment(data), nil
+
+		case '[': // <![
+			// Probably <![CDATA[.
+			for i := 0; i < 6; i++ {
+				if b, ok = p.mustgetc(); !ok {
+					return nil, p.err
+				}
+				if b != "CDATA["[i] {
+					p.err = p.syntaxError("invalid <![ sequence")
+					return nil, p.err
+				}
+			}
+			// Have <![CDATA[.  Read text until ]]>.
+			data := p.text(-1, true)
+			if data == nil {
+				return nil, p.err
+			}
+			return CharData(data), nil
+		}
+
+		// Probably a directive: <!DOCTYPE ...>, <!ENTITY ...>, etc.
+		// We don't care, but accumulate for caller. Quoted angle
+		// brackets do not count for nesting.
+		p.buf.Reset()
+		p.buf.WriteByte(b)
+		inquote := uint8(0)
+		depth := 0
+		for {
+			if b, ok = p.mustgetc(); !ok {
+				return nil, p.err
+			}
+			if inquote == 0 && b == '>' && depth == 0 {
+				break
+			}
+			p.buf.WriteByte(b)
+			switch {
+			case b == inquote:
+				inquote = 0
+
+			case inquote != 0:
+				// in quotes, no special action
+
+			case b == '\'' || b == '"':
+				inquote = b
+
+			case b == '>' && inquote == 0:
+				depth--
+
+			case b == '<' && inquote == 0:
+				depth++
+			}
+		}
+		return Directive(p.buf.Bytes()), nil
+	}
+
+	// Must be an open element like <a href="foo">
+	p.ungetc(b)
+
+	var (
+		name  Name
+		empty bool
+		attr  []Attr
+	)
+	if name, ok = p.nsname(); !ok {
+		if p.err == nil {
+			p.err = p.syntaxError("expected element name after <")
+		}
+		return nil, p.err
+	}
+
+	attr = make([]Attr, 0, 4)
+	for {
+		p.space()
+		if b, ok = p.mustgetc(); !ok {
+			return nil, p.err
+		}
+		if b == '/' {
+			empty = true
+			if b, ok = p.mustgetc(); !ok {
+				return nil, p.err
+			}
+			if b != '>' {
+				p.err = p.syntaxError("expected /> in element")
+				return nil, p.err
+			}
+			break
+		}
+		if b == '>' {
+			break
+		}
+		p.ungetc(b)
+
+		n := len(attr)
+		if n >= cap(attr) {
+			nattr := make([]Attr, n, 2*cap(attr))
+			copy(nattr, attr)
+			attr = nattr
+		}
+		attr = attr[0 : n+1]
+		a := &attr[n]
+		if a.Name, ok = p.nsname(); !ok {
+			if p.err == nil {
+				p.err = p.syntaxError("expected attribute name in element")
+			}
+			return nil, p.err
+		}
+		p.space()
+		if b, ok = p.mustgetc(); !ok {
+			return nil, p.err
+		}
+		if b != '=' {
+			if p.Strict {
+				p.err = p.syntaxError("attribute name without = in element")
+				return nil, p.err
+			} else {
+				p.ungetc(b)
+				a.Value = a.Name.Local
+			}
+		} else {
+			p.space()
+			data := p.attrval()
+			if data == nil {
+				return nil, p.err
+			}
+			a.Value = string(data)
+		}
+	}
+	if empty {
+		p.needClose = true
+		p.toClose = name
+	}
+	return StartElement{name, attr}, nil
+}
+
+func (p *Parser) attrval() []byte {
+	b, ok := p.mustgetc()
+	if !ok {
+		return nil
+	}
+	// Handle quoted attribute values
+	if b == '"' || b == '\'' {
+		return p.text(int(b), false)
+	}
+	// Handle unquoted attribute values for strict parsers
+	if p.Strict {
+		p.err = p.syntaxError("unquoted or missing attribute value in element")
+		return nil
+	}
+	// Handle unquoted attribute values for unstrict parsers
+	p.ungetc(b)
+	p.buf.Reset()
+	for {
+		b, ok = p.mustgetc()
+		if !ok {
+			return nil
+		}
+		// http://www.w3.org/TR/REC-html40/intro/sgmltut.html#h-3.2.2
+		if 'a' <= b && b <= 'z' || 'A' <= b && b <= 'Z' ||
+			'0' <= b && b <= '9' || b == '_' || b == ':' || b == '-' {
+			p.buf.WriteByte(b)
+		} else {
+			p.ungetc(b)
+			break
+		}
+	}
+	return p.buf.Bytes()
+}
+
+// Skip spaces if any
+func (p *Parser) space() {
+	for {
+		b, ok := p.getc()
+		if !ok {
+			return
+		}
+		switch b {
+		case ' ', '\r', '\n', '\t':
+		default:
+			p.ungetc(b)
+			return
+		}
+	}
+}
+
+// Read a single byte.
+// If there is no byte to read, return ok==false
+// and leave the error in p.err.
+// Maintain line number.
+func (p *Parser) getc() (b byte, ok bool) {
+	if p.err != nil {
+		return 0, false
+	}
+	if p.nextByte >= 0 {
+		b = byte(p.nextByte)
+		p.nextByte = -1
+	} else {
+		b, p.err = p.r.ReadByte()
+		if p.err != nil {
+			return 0, false
+		}
+		if p.saved != nil {
+			p.saved.WriteByte(b)
+		}
+	}
+	if b == '\n' {
+		p.line++
+	}
+	return b, true
+}
+
+// Return saved offset.
+// If we did ungetc (nextByte >= 0), have to back up one.
+func (p *Parser) savedOffset() int {
+	n := p.saved.Len()
+	if p.nextByte >= 0 {
+		n--
+	}
+	return n
+}
+
+// Must read a single byte.
+// If there is no byte to read,
+// set p.err to SyntaxError("unexpected EOF")
+// and return ok==false
+func (p *Parser) mustgetc() (b byte, ok bool) {
+	if b, ok = p.getc(); !ok {
+		if p.err == io.EOF {
+			p.err = p.syntaxError("unexpected EOF")
+		}
+	}
+	return
+}
+
+// Unread a single byte.
+func (p *Parser) ungetc(b byte) {
+	if b == '\n' {
+		p.line--
+	}
+	p.nextByte = int(b)
+}
+
+var entity = map[string]int{
+	"lt":   '<',
+	"gt":   '>',
+	"amp":  '&',
+	"apos": '\'',
+	"quot": '"',
+}
+
+// Read plain text section (XML calls it character data).
+// If quote >= 0, we are in a quoted string and need to find the matching quote.
+// If cdata == true, we are in a <![CDATA[ section and need to find ]]>.
+// On failure return nil and leave the error in p.err.
+func (p *Parser) text(quote int, cdata bool) []byte {
+	var b0, b1 byte
+	var trunc int
+	p.buf.Reset()
+Input:
+	for {
+		b, ok := p.getc()
+		if !ok {
+			if cdata {
+				if p.err == io.EOF {
+					p.err = p.syntaxError("unexpected EOF in CDATA section")
+				}
+				return nil
+			}
+			break Input
+		}
+
+		// <![CDATA[ section ends with ]]>.
+		// It is an error for ]]> to appear in ordinary text.
+		if b0 == ']' && b1 == ']' && b == '>' {
+			if cdata {
+				trunc = 2
+				break Input
+			}
+			p.err = p.syntaxError("unescaped ]]> not in CDATA section")
+			return nil
+		}
+
+		// Stop reading text if we see a <.
+		if b == '<' && !cdata {
+			if quote >= 0 {
+				p.err = p.syntaxError("unescaped < inside quoted string")
+				return nil
+			}
+			p.ungetc('<')
+			break Input
+		}
+		if quote >= 0 && b == byte(quote) {
+			break Input
+		}
+		if b == '&' && !cdata {
+			// Read escaped character expression up to semicolon.
+			// XML in all its glory allows a document to define and use
+			// its own character names with <!ENTITY ...> directives.
+			// Parsers are required to recognize lt, gt, amp, apos, and quot
+			// even if they have not been declared.  That's all we allow.
+			var i int
+			for i = 0; i < len(p.tmp); i++ {
+				var ok bool
+				p.tmp[i], ok = p.getc()
+				if !ok {
+					if p.err == io.EOF {
+						p.err = p.syntaxError("unexpected EOF")
+					}
+					return nil
+				}
+				c := p.tmp[i]
+				if c == ';' {
+					break
+				}
+				if 'a' <= c && c <= 'z' ||
+					'A' <= c && c <= 'Z' ||
+					'0' <= c && c <= '9' ||
+					c == '_' || c == '#' {
+					continue
+				}
+				p.ungetc(c)
+				break
+			}
+			s := string(p.tmp[0:i])
+			if i >= len(p.tmp) {
+				if !p.Strict {
+					b0, b1 = 0, 0
+					p.buf.WriteByte('&')
+					p.buf.Write(p.tmp[0:i])
+					continue Input
+				}
+				p.err = p.syntaxError("character entity expression &" + s + "... too long")
+				return nil
+			}
+			var haveText bool
+			var text string
+			if i >= 2 && s[0] == '#' {
+				var n uint64
+				var err error
+				if i >= 3 && s[1] == 'x' {
+					n, err = strconv.Btoui64(s[2:], 16)
+				} else {
+					n, err = strconv.Btoui64(s[1:], 10)
+				}
+				if err == nil && n <= unicode.MaxRune {
+					text = string(n)
+					haveText = true
+				}
+			} else {
+				if r, ok := entity[s]; ok {
+					text = string(r)
+					haveText = true
+				} else if p.Entity != nil {
+					text, haveText = p.Entity[s]
+				}
+			}
+			if !haveText {
+				if !p.Strict {
+					b0, b1 = 0, 0
+					p.buf.WriteByte('&')
+					p.buf.Write(p.tmp[0:i])
+					continue Input
+				}
+				p.err = p.syntaxError("invalid character entity &" + s + ";")
+				return nil
+			}
+			p.buf.Write([]byte(text))
+			b0, b1 = 0, 0
+			continue Input
+		}
+		p.buf.WriteByte(b)
+		b0, b1 = b1, b
+	}
+	data := p.buf.Bytes()
+	data = data[0 : len(data)-trunc]
+
+	// Inspect each rune for being a disallowed character.
+	buf := data
+	for len(buf) > 0 {
+		r, size := utf8.DecodeRune(buf)
+		if r == utf8.RuneError && size == 1 {
+			p.err = p.syntaxError("invalid UTF-8")
+			return nil
+		}
+		buf = buf[size:]
+		if !isInCharacterRange(r) {
+			p.err = p.syntaxError(fmt.Sprintf("illegal character code %U", r))
+			return nil
+		}
+	}
+
+	// Must rewrite \r and \r\n into \n.
+	w := 0
+	for r := 0; r < len(data); r++ {
+		b := data[r]
+		if b == '\r' {
+			if r+1 < len(data) && data[r+1] == '\n' {
+				continue
+			}
+			b = '\n'
+		}
+		data[w] = b
+		w++
+	}
+	return data[0:w]
+}
+
+// Decide whether the given rune is in the XML Character Range, per
+// the Char production of http://www.xml.com/axml/testaxml.htm,
+// Section 2.2 Characters.
+func isInCharacterRange(r rune) (inrange bool) {
+	return r == 0x09 ||
+		r == 0x0A ||
+		r == 0x0D ||
+		r >= 0x20 && r <= 0xDF77 ||
+		r >= 0xE000 && r <= 0xFFFD ||
+		r >= 0x10000 && r <= 0x10FFFF
+}
+
+// Get name space name: name with a : stuck in the middle.
+// The part before the : is the name space identifier.
+func (p *Parser) nsname() (name Name, ok bool) {
+	s, ok := p.name()
+	if !ok {
+		return
+	}
+	i := strings.Index(s, ":")
+	if i < 0 {
+		name.Local = s
+	} else {
+		name.Space = s[0:i]
+		name.Local = s[i+1:]
+	}
+	return name, true
+}
+
+// Get name: /first(first|second)*/
+// Do not set p.err if the name is missing (unless unexpected EOF is received):
+// let the caller provide better context.
+func (p *Parser) name() (s string, ok bool) {
+	var b byte
+	if b, ok = p.mustgetc(); !ok {
+		return
+	}
+
+	// As a first approximation, we gather the bytes [A-Za-z_:.-\x80-\xFF]*
+	if b < utf8.RuneSelf && !isNameByte(b) {
+		p.ungetc(b)
+		return "", false
+	}
+	p.buf.Reset()
+	p.buf.WriteByte(b)
+	for {
+		if b, ok = p.mustgetc(); !ok {
+			return
+		}
+		if b < utf8.RuneSelf && !isNameByte(b) {
+			p.ungetc(b)
+			break
+		}
+		p.buf.WriteByte(b)
+	}
+
+	// Then we check the characters.
+	s = p.buf.String()
+	for i, c := range s {
+		if !unicode.Is(first, c) && (i == 0 || !unicode.Is(second, c)) {
+			p.err = p.syntaxError("invalid XML name: " + s)
+			return "", false
+		}
+	}
+	return s, true
+}
+
+func isNameByte(c byte) bool {
+	return 'A' <= c && c <= 'Z' ||
+		'a' <= c && c <= 'z' ||
+		'0' <= c && c <= '9' ||
+		c == '_' || c == ':' || c == '.' || c == '-'
+}
+
+// These tables were generated by cut and paste from Appendix B of
+// the XML spec at http://www.xml.com/axml/testaxml.htm
+// and then reformatting.  First corresponds to (Letter | '_' | ':')
+// and second corresponds to NameChar.
+
+var first = &unicode.RangeTable{
+	R16: []unicode.Range16{
+		{0x003A, 0x003A, 1},
+		{0x0041, 0x005A, 1},
+		{0x005F, 0x005F, 1},
+		{0x0061, 0x007A, 1},
+		{0x00C0, 0x00D6, 1},
+		{0x00D8, 0x00F6, 1},
+		{0x00F8, 0x00FF, 1},
+		{0x0100, 0x0131, 1},
+		{0x0134, 0x013E, 1},
+		{0x0141, 0x0148, 1},
+		{0x014A, 0x017E, 1},
+		{0x0180, 0x01C3, 1},
+		{0x01CD, 0x01F0, 1},
+		{0x01F4, 0x01F5, 1},
+		{0x01FA, 0x0217, 1},
+		{0x0250, 0x02A8, 1},
+		{0x02BB, 0x02C1, 1},
+		{0x0386, 0x0386, 1},
+		{0x0388, 0x038A, 1},
+		{0x038C, 0x038C, 1},
+		{0x038E, 0x03A1, 1},
+		{0x03A3, 0x03CE, 1},
+		{0x03D0, 0x03D6, 1},
+		{0x03DA, 0x03E0, 2},
+		{0x03E2, 0x03F3, 1},
+		{0x0401, 0x040C, 1},
+		{0x040E, 0x044F, 1},
+		{0x0451, 0x045C, 1},
+		{0x045E, 0x0481, 1},
+		{0x0490, 0x04C4, 1},
+		{0x04C7, 0x04C8, 1},
+		{0x04CB, 0x04CC, 1},
+		{0x04D0, 0x04EB, 1},
+		{0x04EE, 0x04F5, 1},
+		{0x04F8, 0x04F9, 1},
+		{0x0531, 0x0556, 1},
+		{0x0559, 0x0559, 1},
+		{0x0561, 0x0586, 1},
+		{0x05D0, 0x05EA, 1},
+		{0x05F0, 0x05F2, 1},
+		{0x0621, 0x063A, 1},
+		{0x0641, 0x064A, 1},
+		{0x0671, 0x06B7, 1},
+		{0x06BA, 0x06BE, 1},
+		{0x06C0, 0x06CE, 1},
+		{0x06D0, 0x06D3, 1},
+		{0x06D5, 0x06D5, 1},
+		{0x06E5, 0x06E6, 1},
+		{0x0905, 0x0939, 1},
+		{0x093D, 0x093D, 1},
+		{0x0958, 0x0961, 1},
+		{0x0985, 0x098C, 1},
+		{0x098F, 0x0990, 1},
+		{0x0993, 0x09A8, 1},
+		{0x09AA, 0x09B0, 1},
+		{0x09B2, 0x09B2, 1},
+		{0x09B6, 0x09B9, 1},
+		{0x09DC, 0x09DD, 1},
+		{0x09DF, 0x09E1, 1},
+		{0x09F0, 0x09F1, 1},
+		{0x0A05, 0x0A0A, 1},
+		{0x0A0F, 0x0A10, 1},
+		{0x0A13, 0x0A28, 1},
+		{0x0A2A, 0x0A30, 1},
+		{0x0A32, 0x0A33, 1},
+		{0x0A35, 0x0A36, 1},
+		{0x0A38, 0x0A39, 1},
+		{0x0A59, 0x0A5C, 1},
+		{0x0A5E, 0x0A5E, 1},
+		{0x0A72, 0x0A74, 1},
+		{0x0A85, 0x0A8B, 1},
+		{0x0A8D, 0x0A8D, 1},
+		{0x0A8F, 0x0A91, 1},
+		{0x0A93, 0x0AA8, 1},
+		{0x0AAA, 0x0AB0, 1},
+		{0x0AB2, 0x0AB3, 1},
+		{0x0AB5, 0x0AB9, 1},
+		{0x0ABD, 0x0AE0, 0x23},
+		{0x0B05, 0x0B0C, 1},
+		{0x0B0F, 0x0B10, 1},
+		{0x0B13, 0x0B28, 1},
+		{0x0B2A, 0x0B30, 1},
+		{0x0B32, 0x0B33, 1},
+		{0x0B36, 0x0B39, 1},
+		{0x0B3D, 0x0B3D, 1},
+		{0x0B5C, 0x0B5D, 1},
+		{0x0B5F, 0x0B61, 1},
+		{0x0B85, 0x0B8A, 1},
+		{0x0B8E, 0x0B90, 1},
+		{0x0B92, 0x0B95, 1},
+		{0x0B99, 0x0B9A, 1},
+		{0x0B9C, 0x0B9C, 1},
+		{0x0B9E, 0x0B9F, 1},
+		{0x0BA3, 0x0BA4, 1},
+		{0x0BA8, 0x0BAA, 1},
+		{0x0BAE, 0x0BB5, 1},
+		{0x0BB7, 0x0BB9, 1},
+		{0x0C05, 0x0C0C, 1},
+		{0x0C0E, 0x0C10, 1},
+		{0x0C12, 0x0C28, 1},
+		{0x0C2A, 0x0C33, 1},
+		{0x0C35, 0x0C39, 1},
+		{0x0C60, 0x0C61, 1},
+		{0x0C85, 0x0C8C, 1},
+		{0x0C8E, 0x0C90, 1},
+		{0x0C92, 0x0CA8, 1},
+		{0x0CAA, 0x0CB3, 1},
+		{0x0CB5, 0x0CB9, 1},
+		{0x0CDE, 0x0CDE, 1},
+		{0x0CE0, 0x0CE1, 1},
+		{0x0D05, 0x0D0C, 1},
+		{0x0D0E, 0x0D10, 1},
+		{0x0D12, 0x0D28, 1},
+		{0x0D2A, 0x0D39, 1},
+		{0x0D60, 0x0D61, 1},
+		{0x0E01, 0x0E2E, 1},
+		{0x0E30, 0x0E30, 1},
+		{0x0E32, 0x0E33, 1},
+		{0x0E40, 0x0E45, 1},
+		{0x0E81, 0x0E82, 1},
+		{0x0E84, 0x0E84, 1},
+		{0x0E87, 0x0E88, 1},
+		{0x0E8A, 0x0E8D, 3},
+		{0x0E94, 0x0E97, 1},
+		{0x0E99, 0x0E9F, 1},
+		{0x0EA1, 0x0EA3, 1},
+		{0x0EA5, 0x0EA7, 2},
+		{0x0EAA, 0x0EAB, 1},
+		{0x0EAD, 0x0EAE, 1},
+		{0x0EB0, 0x0EB0, 1},
+		{0x0EB2, 0x0EB3, 1},
+		{0x0EBD, 0x0EBD, 1},
+		{0x0EC0, 0x0EC4, 1},
+		{0x0F40, 0x0F47, 1},
+		{0x0F49, 0x0F69, 1},
+		{0x10A0, 0x10C5, 1},
+		{0x10D0, 0x10F6, 1},
+		{0x1100, 0x1100, 1},
+		{0x1102, 0x1103, 1},
+		{0x1105, 0x1107, 1},
+		{0x1109, 0x1109, 1},
+		{0x110B, 0x110C, 1},
+		{0x110E, 0x1112, 1},
+		{0x113C, 0x1140, 2},
+		{0x114C, 0x1150, 2},
+		{0x1154, 0x1155, 1},
+		{0x1159, 0x1159, 1},
+		{0x115F, 0x1161, 1},
+		{0x1163, 0x1169, 2},
+		{0x116D, 0x116E, 1},
+		{0x1172, 0x1173, 1},
+		{0x1175, 0x119E, 0x119E - 0x1175},
+		{0x11A8, 0x11AB, 0x11AB - 0x11A8},
+		{0x11AE, 0x11AF, 1},
+		{0x11B7, 0x11B8, 1},
+		{0x11BA, 0x11BA, 1},
+		{0x11BC, 0x11C2, 1},
+		{0x11EB, 0x11F0, 0x11F0 - 0x11EB},
+		{0x11F9, 0x11F9, 1},
+		{0x1E00, 0x1E9B, 1},
+		{0x1EA0, 0x1EF9, 1},
+		{0x1F00, 0x1F15, 1},
+		{0x1F18, 0x1F1D, 1},
+		{0x1F20, 0x1F45, 1},
+		{0x1F48, 0x1F4D, 1},
+		{0x1F50, 0x1F57, 1},
+		{0x1F59, 0x1F5B, 0x1F5B - 0x1F59},
+		{0x1F5D, 0x1F5D, 1},
+		{0x1F5F, 0x1F7D, 1},
+		{0x1F80, 0x1FB4, 1},
+		{0x1FB6, 0x1FBC, 1},
+		{0x1FBE, 0x1FBE, 1},
+		{0x1FC2, 0x1FC4, 1},
+		{0x1FC6, 0x1FCC, 1},
+		{0x1FD0, 0x1FD3, 1},
+		{0x1FD6, 0x1FDB, 1},
+		{0x1FE0, 0x1FEC, 1},
+		{0x1FF2, 0x1FF4, 1},
+		{0x1FF6, 0x1FFC, 1},
+		{0x2126, 0x2126, 1},
+		{0x212A, 0x212B, 1},
+		{0x212E, 0x212E, 1},
+		{0x2180, 0x2182, 1},
+		{0x3007, 0x3007, 1},
+		{0x3021, 0x3029, 1},
+		{0x3041, 0x3094, 1},
+		{0x30A1, 0x30FA, 1},
+		{0x3105, 0x312C, 1},
+		{0x4E00, 0x9FA5, 1},
+		{0xAC00, 0xD7A3, 1},
+	},
+}
+
+var second = &unicode.RangeTable{
+	R16: []unicode.Range16{
+		{0x002D, 0x002E, 1},
+		{0x0030, 0x0039, 1},
+		{0x00B7, 0x00B7, 1},
+		{0x02D0, 0x02D1, 1},
+		{0x0300, 0x0345, 1},
+		{0x0360, 0x0361, 1},
+		{0x0387, 0x0387, 1},
+		{0x0483, 0x0486, 1},
+		{0x0591, 0x05A1, 1},
+		{0x05A3, 0x05B9, 1},
+		{0x05BB, 0x05BD, 1},
+		{0x05BF, 0x05BF, 1},
+		{0x05C1, 0x05C2, 1},
+		{0x05C4, 0x0640, 0x0640 - 0x05C4},
+		{0x064B, 0x0652, 1},
+		{0x0660, 0x0669, 1},
+		{0x0670, 0x0670, 1},
+		{0x06D6, 0x06DC, 1},
+		{0x06DD, 0x06DF, 1},
+		{0x06E0, 0x06E4, 1},
+		{0x06E7, 0x06E8, 1},
+		{0x06EA, 0x06ED, 1},
+		{0x06F0, 0x06F9, 1},
+		{0x0901, 0x0903, 1},
+		{0x093C, 0x093C, 1},
+		{0x093E, 0x094C, 1},
+		{0x094D, 0x094D, 1},
+		{0x0951, 0x0954, 1},
+		{0x0962, 0x0963, 1},
+		{0x0966, 0x096F, 1},
+		{0x0981, 0x0983, 1},
+		{0x09BC, 0x09BC, 1},
+		{0x09BE, 0x09BF, 1},
+		{0x09C0, 0x09C4, 1},
+		{0x09C7, 0x09C8, 1},
+		{0x09CB, 0x09CD, 1},
+		{0x09D7, 0x09D7, 1},
+		{0x09E2, 0x09E3, 1},
+		{0x09E6, 0x09EF, 1},
+		{0x0A02, 0x0A3C, 0x3A},
+		{0x0A3E, 0x0A3F, 1},
+		{0x0A40, 0x0A42, 1},
+		{0x0A47, 0x0A48, 1},
+		{0x0A4B, 0x0A4D, 1},
+		{0x0A66, 0x0A6F, 1},
+		{0x0A70, 0x0A71, 1},
+		{0x0A81, 0x0A83, 1},
+		{0x0ABC, 0x0ABC, 1},
+		{0x0ABE, 0x0AC5, 1},
+		{0x0AC7, 0x0AC9, 1},
+		{0x0ACB, 0x0ACD, 1},
+		{0x0AE6, 0x0AEF, 1},
+		{0x0B01, 0x0B03, 1},
+		{0x0B3C, 0x0B3C, 1},
+		{0x0B3E, 0x0B43, 1},
+		{0x0B47, 0x0B48, 1},
+		{0x0B4B, 0x0B4D, 1},
+		{0x0B56, 0x0B57, 1},
+		{0x0B66, 0x0B6F, 1},
+		{0x0B82, 0x0B83, 1},
+		{0x0BBE, 0x0BC2, 1},
+		{0x0BC6, 0x0BC8, 1},
+		{0x0BCA, 0x0BCD, 1},
+		{0x0BD7, 0x0BD7, 1},
+		{0x0BE7, 0x0BEF, 1},
+		{0x0C01, 0x0C03, 1},
+		{0x0C3E, 0x0C44, 1},
+		{0x0C46, 0x0C48, 1},
+		{0x0C4A, 0x0C4D, 1},
+		{0x0C55, 0x0C56, 1},
+		{0x0C66, 0x0C6F, 1},
+		{0x0C82, 0x0C83, 1},
+		{0x0CBE, 0x0CC4, 1},
+		{0x0CC6, 0x0CC8, 1},
+		{0x0CCA, 0x0CCD, 1},
+		{0x0CD5, 0x0CD6, 1},
+		{0x0CE6, 0x0CEF, 1},
+		{0x0D02, 0x0D03, 1},
+		{0x0D3E, 0x0D43, 1},
+		{0x0D46, 0x0D48, 1},
+		{0x0D4A, 0x0D4D, 1},
+		{0x0D57, 0x0D57, 1},
+		{0x0D66, 0x0D6F, 1},
+		{0x0E31, 0x0E31, 1},
+		{0x0E34, 0x0E3A, 1},
+		{0x0E46, 0x0E46, 1},
+		{0x0E47, 0x0E4E, 1},
+		{0x0E50, 0x0E59, 1},
+		{0x0EB1, 0x0EB1, 1},
+		{0x0EB4, 0x0EB9, 1},
+		{0x0EBB, 0x0EBC, 1},
+		{0x0EC6, 0x0EC6, 1},
+		{0x0EC8, 0x0ECD, 1},
+		{0x0ED0, 0x0ED9, 1},
+		{0x0F18, 0x0F19, 1},
+		{0x0F20, 0x0F29, 1},
+		{0x0F35, 0x0F39, 2},
+		{0x0F3E, 0x0F3F, 1},
+		{0x0F71, 0x0F84, 1},
+		{0x0F86, 0x0F8B, 1},
+		{0x0F90, 0x0F95, 1},
+		{0x0F97, 0x0F97, 1},
+		{0x0F99, 0x0FAD, 1},
+		{0x0FB1, 0x0FB7, 1},
+		{0x0FB9, 0x0FB9, 1},
+		{0x20D0, 0x20DC, 1},
+		{0x20E1, 0x3005, 0x3005 - 0x20E1},
+		{0x302A, 0x302F, 1},
+		{0x3031, 0x3035, 1},
+		{0x3099, 0x309A, 1},
+		{0x309D, 0x309E, 1},
+		{0x30FC, 0x30FE, 1},
+	},
+}
+
+// HTMLEntity is an entity map containing translations for the
+// standard HTML entity characters.
+var HTMLEntity = htmlEntity
+
+var htmlEntity = map[string]string{
+	/*
+		hget http://www.w3.org/TR/html4/sgml/entities.html |
+		ssam '
+			,y /\&gt;/ x/\&lt;(.|\n)+/ s/\n/ /g
+			,x v/^\&lt;!ENTITY/d
+			,s/\&lt;!ENTITY ([^ ]+) .*U\+([0-9A-F][0-9A-F][0-9A-F][0-9A-F]) .+/	"\1": "\\u\2",/g
+		'
+	*/
+	"nbsp":     "\u00A0",
+	"iexcl":    "\u00A1",
+	"cent":     "\u00A2",
+	"pound":    "\u00A3",
+	"curren":   "\u00A4",
+	"yen":      "\u00A5",
+	"brvbar":   "\u00A6",
+	"sect":     "\u00A7",
+	"uml":      "\u00A8",
+	"copy":     "\u00A9",
+	"ordf":     "\u00AA",
+	"laquo":    "\u00AB",
+	"not":      "\u00AC",
+	"shy":      "\u00AD",
+	"reg":      "\u00AE",
+	"macr":     "\u00AF",
+	"deg":      "\u00B0",
+	"plusmn":   "\u00B1",
+	"sup2":     "\u00B2",
+	"sup3":     "\u00B3",
+	"acute":    "\u00B4",
+	"micro":    "\u00B5",
+	"para":     "\u00B6",
+	"middot":   "\u00B7",
+	"cedil":    "\u00B8",
+	"sup1":     "\u00B9",
+	"ordm":     "\u00BA",
+	"raquo":    "\u00BB",
+	"frac14":   "\u00BC",
+	"frac12":   "\u00BD",
+	"frac34":   "\u00BE",
+	"iquest":   "\u00BF",
+	"Agrave":   "\u00C0",
+	"Aacute":   "\u00C1",
+	"Acirc":    "\u00C2",
+	"Atilde":   "\u00C3",
+	"Auml":     "\u00C4",
+	"Aring":    "\u00C5",
+	"AElig":    "\u00C6",
+	"Ccedil":   "\u00C7",
+	"Egrave":   "\u00C8",
+	"Eacute":   "\u00C9",
+	"Ecirc":    "\u00CA",
+	"Euml":     "\u00CB",
+	"Igrave":   "\u00CC",
+	"Iacute":   "\u00CD",
+	"Icirc":    "\u00CE",
+	"Iuml":     "\u00CF",
+	"ETH":      "\u00D0",
+	"Ntilde":   "\u00D1",
+	"Ograve":   "\u00D2",
+	"Oacute":   "\u00D3",
+	"Ocirc":    "\u00D4",
+	"Otilde":   "\u00D5",
+	"Ouml":     "\u00D6",
+	"times":    "\u00D7",
+	"Oslash":   "\u00D8",
+	"Ugrave":   "\u00D9",
+	"Uacute":   "\u00DA",
+	"Ucirc":    "\u00DB",
+	"Uuml":     "\u00DC",
+	"Yacute":   "\u00DD",
+	"THORN":    "\u00DE",
+	"szlig":    "\u00DF",
+	"agrave":   "\u00E0",
+	"aacute":   "\u00E1",
+	"acirc":    "\u00E2",
+	"atilde":   "\u00E3",
+	"auml":     "\u00E4",
+	"aring":    "\u00E5",
+	"aelig":    "\u00E6",
+	"ccedil":   "\u00E7",
+	"egrave":   "\u00E8",
+	"eacute":   "\u00E9",
+	"ecirc":    "\u00EA",
+	"euml":     "\u00EB",
+	"igrave":   "\u00EC",
+	"iacute":   "\u00ED",
+	"icirc":    "\u00EE",
+	"iuml":     "\u00EF",
+	"eth":      "\u00F0",
+	"ntilde":   "\u00F1",
+	"ograve":   "\u00F2",
+	"oacute":   "\u00F3",
+	"ocirc":    "\u00F4",
+	"otilde":   "\u00F5",
+	"ouml":     "\u00F6",
+	"divide":   "\u00F7",
+	"oslash":   "\u00F8",
+	"ugrave":   "\u00F9",
+	"uacute":   "\u00FA",
+	"ucirc":    "\u00FB",
+	"uuml":     "\u00FC",
+	"yacute":   "\u00FD",
+	"thorn":    "\u00FE",
+	"yuml":     "\u00FF",
+	"fnof":     "\u0192",
+	"Alpha":    "\u0391",
+	"Beta":     "\u0392",
+	"Gamma":    "\u0393",
+	"Delta":    "\u0394",
+	"Epsilon":  "\u0395",
+	"Zeta":     "\u0396",
+	"Eta":      "\u0397",
+	"Theta":    "\u0398",
+	"Iota":     "\u0399",
+	"Kappa":    "\u039A",
+	"Lambda":   "\u039B",
+	"Mu":       "\u039C",
+	"Nu":       "\u039D",
+	"Xi":       "\u039E",
+	"Omicron":  "\u039F",
+	"Pi":       "\u03A0",
+	"Rho":      "\u03A1",
+	"Sigma":    "\u03A3",
+	"Tau":      "\u03A4",
+	"Upsilon":  "\u03A5",
+	"Phi":      "\u03A6",
+	"Chi":      "\u03A7",
+	"Psi":      "\u03A8",
+	"Omega":    "\u03A9",
+	"alpha":    "\u03B1",
+	"beta":     "\u03B2",
+	"gamma":    "\u03B3",
+	"delta":    "\u03B4",
+	"epsilon":  "\u03B5",
+	"zeta":     "\u03B6",
+	"eta":      "\u03B7",
+	"theta":    "\u03B8",
+	"iota":     "\u03B9",
+	"kappa":    "\u03BA",
+	"lambda":   "\u03BB",
+	"mu":       "\u03BC",
+	"nu":       "\u03BD",
+	"xi":       "\u03BE",
+	"omicron":  "\u03BF",
+	"pi":       "\u03C0",
+	"rho":      "\u03C1",
+	"sigmaf":   "\u03C2",
+	"sigma":    "\u03C3",
+	"tau":      "\u03C4",
+	"upsilon":  "\u03C5",
+	"phi":      "\u03C6",
+	"chi":      "\u03C7",
+	"psi":      "\u03C8",
+	"omega":    "\u03C9",
+	"thetasym": "\u03D1",
+	"upsih":    "\u03D2",
+	"piv":      "\u03D6",
+	"bull":     "\u2022",
+	"hellip":   "\u2026",
+	"prime":    "\u2032",
+	"Prime":    "\u2033",
+	"oline":    "\u203E",
+	"frasl":    "\u2044",
+	"weierp":   "\u2118",
+	"image":    "\u2111",
+	"real":     "\u211C",
+	"trade":    "\u2122",
+	"alefsym":  "\u2135",
+	"larr":     "\u2190",
+	"uarr":     "\u2191",
+	"rarr":     "\u2192",
+	"darr":     "\u2193",
+	"harr":     "\u2194",
+	"crarr":    "\u21B5",
+	"lArr":     "\u21D0",
+	"uArr":     "\u21D1",
+	"rArr":     "\u21D2",
+	"dArr":     "\u21D3",
+	"hArr":     "\u21D4",
+	"forall":   "\u2200",
+	"part":     "\u2202",
+	"exist":    "\u2203",
+	"empty":    "\u2205",
+	"nabla":    "\u2207",
+	"isin":     "\u2208",
+	"notin":    "\u2209",
+	"ni":       "\u220B",
+	"prod":     "\u220F",
+	"sum":      "\u2211",
+	"minus":    "\u2212",
+	"lowast":   "\u2217",
+	"radic":    "\u221A",
+	"prop":     "\u221D",
+	"infin":    "\u221E",
+	"ang":      "\u2220",
+	"and":      "\u2227",
+	"or":       "\u2228",
+	"cap":      "\u2229",
+	"cup":      "\u222A",
+	"int":      "\u222B",
+	"there4":   "\u2234",
+	"sim":      "\u223C",
+	"cong":     "\u2245",
+	"asymp":    "\u2248",
+	"ne":       "\u2260",
+	"equiv":    "\u2261",
+	"le":       "\u2264",
+	"ge":       "\u2265",
+	"sub":      "\u2282",
+	"sup":      "\u2283",
+	"nsub":     "\u2284",
+	"sube":     "\u2286",
+	"supe":     "\u2287",
+	"oplus":    "\u2295",
+	"otimes":   "\u2297",
+	"perp":     "\u22A5",
+	"sdot":     "\u22C5",
+	"lceil":    "\u2308",
+	"rceil":    "\u2309",
+	"lfloor":   "\u230A",
+	"rfloor":   "\u230B",
+	"lang":     "\u2329",
+	"rang":     "\u232A",
+	"loz":      "\u25CA",
+	"spades":   "\u2660",
+	"clubs":    "\u2663",
+	"hearts":   "\u2665",
+	"diams":    "\u2666",
+	"quot":     "\u0022",
+	"amp":      "\u0026",
+	"lt":       "\u003C",
+	"gt":       "\u003E",
+	"OElig":    "\u0152",
+	"oelig":    "\u0153",
+	"Scaron":   "\u0160",
+	"scaron":   "\u0161",
+	"Yuml":     "\u0178",
+	"circ":     "\u02C6",
+	"tilde":    "\u02DC",
+	"ensp":     "\u2002",
+	"emsp":     "\u2003",
+	"thinsp":   "\u2009",
+	"zwnj":     "\u200C",
+	"zwj":      "\u200D",
+	"lrm":      "\u200E",
+	"rlm":      "\u200F",
+	"ndash":    "\u2013",
+	"mdash":    "\u2014",
+	"lsquo":    "\u2018",
+	"rsquo":    "\u2019",
+	"sbquo":    "\u201A",
+	"ldquo":    "\u201C",
+	"rdquo":    "\u201D",
+	"bdquo":    "\u201E",
+	"dagger":   "\u2020",
+	"Dagger":   "\u2021",
+	"permil":   "\u2030",
+	"lsaquo":   "\u2039",
+	"rsaquo":   "\u203A",
+	"euro":     "\u20AC",
+}
+
+// HTMLAutoClose is the set of HTML elements that
+// should be considered to close automatically.
+var HTMLAutoClose = htmlAutoClose
+
+var htmlAutoClose = []string{
+	/*
+		hget http://www.w3.org/TR/html4/loose.dtd |
+		9 sed -n 's/<!ELEMENT (.*) - O EMPTY.+/	"\1",/p' | tr A-Z a-z
+	*/
+	"basefont",
+	"br",
+	"area",
+	"link",
+	"img",
+	"param",
+	"hr",
+	"input",
+	"col     ",
+	"frame",
+	"isindex",
+	"base",
+	"meta",
+}
+
+var (
+	esc_quot = []byte("&#34;") // shorter than "&quot;"
+	esc_apos = []byte("&#39;") // shorter than "&apos;"
+	esc_amp  = []byte("&amp;")
+	esc_lt   = []byte("&lt;")
+	esc_gt   = []byte("&gt;")
+)
+
+// Escape writes to w the properly escaped XML equivalent
+// of the plain text data s.
+func Escape(w io.Writer, s []byte) {
+	var esc []byte
+	last := 0
+	for i, c := range s {
+		switch c {
+		case '"':
+			esc = esc_quot
+		case '\'':
+			esc = esc_apos
+		case '&':
+			esc = esc_amp
+		case '<':
+			esc = esc_lt
+		case '>':
+			esc = esc_gt
+		default:
+			continue
+		}
+		w.Write(s[last:i])
+		w.Write(esc)
+		last = i + 1
+	}
+	w.Write(s[last:])
+}
+
+// procInstEncoding parses the `encoding="..."` or `encoding='...'`
+// value out of the provided string, returning "" if not found.
+func procInstEncoding(s string) string {
+	// TODO: this parsing is somewhat lame and not exact.
+	// It works for all actual cases, though.
+	idx := strings.Index(s, "encoding=")
+	if idx == -1 {
+		return ""
+	}
+	v := s[idx+len("encoding="):]
+	if v == "" {
+		return ""
+	}
+	if v[0] != '\'' && v[0] != '"' {
+		return ""
+	}
+	idx = strings.IndexRune(v[1:], rune(v[0]))
+	if idx == -1 {
+		return ""
+	}
+	return v[1 : idx+1]
+}
diff --git a/libgo/go/encoding/xml/xml_test.go b/libgo/go/encoding/xml/xml_test.go
new file mode 100644
index 00000000000..6c874fadb7a
--- /dev/null
+++ b/libgo/go/encoding/xml/xml_test.go
@@ -0,0 +1,609 @@
+// Copyright 2009 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package xml
+
+import (
+	"bytes"
+	"io"
+	"os"
+	"reflect"
+	"strings"
+	"testing"
+)
+
+const testInput = `
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
+  "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
+<body xmlns:foo="ns1" xmlns="ns2" xmlns:tag="ns3" ` +
+	"\r\n\t" + `  >
+  <hello lang="en">World &lt;&gt;&apos;&quot; &#x767d;&#40300;翔</hello>
+  <goodbye />
+  <outer foo:attr="value" xmlns:tag="ns4">
+    <inner/>
+  </outer>
+  <tag:name>
+    <![CDATA[Some text here.]]>
+  </tag:name>
+</body><!-- missing final newline -->`
+
+var rawTokens = []Token{
+	CharData([]byte("\n")),
+	ProcInst{"xml", []byte(`version="1.0" encoding="UTF-8"`)},
+	CharData([]byte("\n")),
+	Directive([]byte(`DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
+  "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"`),
+	),
+	CharData([]byte("\n")),
+	StartElement{Name{"", "body"}, []Attr{{Name{"xmlns", "foo"}, "ns1"}, {Name{"", "xmlns"}, "ns2"}, {Name{"xmlns", "tag"}, "ns3"}}},
+	CharData([]byte("\n  ")),
+	StartElement{Name{"", "hello"}, []Attr{{Name{"", "lang"}, "en"}}},
+	CharData([]byte("World <>'\" 白鵬翔")),
+	EndElement{Name{"", "hello"}},
+	CharData([]byte("\n  ")),
+	StartElement{Name{"", "goodbye"}, nil},
+	EndElement{Name{"", "goodbye"}},
+	CharData([]byte("\n  ")),
+	StartElement{Name{"", "outer"}, []Attr{{Name{"foo", "attr"}, "value"}, {Name{"xmlns", "tag"}, "ns4"}}},
+	CharData([]byte("\n    ")),
+	StartElement{Name{"", "inner"}, nil},
+	EndElement{Name{"", "inner"}},
+	CharData([]byte("\n  ")),
+	EndElement{Name{"", "outer"}},
+	CharData([]byte("\n  ")),
+	StartElement{Name{"tag", "name"}, nil},
+	CharData([]byte("\n    ")),
+	CharData([]byte("Some text here.")),
+	CharData([]byte("\n  ")),
+	EndElement{Name{"tag", "name"}},
+	CharData([]byte("\n")),
+	EndElement{Name{"", "body"}},
+	Comment([]byte(" missing final newline ")),
+}
+
+var cookedTokens = []Token{
+	CharData([]byte("\n")),
+	ProcInst{"xml", []byte(`version="1.0" encoding="UTF-8"`)},
+	CharData([]byte("\n")),
+	Directive([]byte(`DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
+  "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"`),
+	),
+	CharData([]byte("\n")),
+	StartElement{Name{"ns2", "body"}, []Attr{{Name{"xmlns", "foo"}, "ns1"}, {Name{"", "xmlns"}, "ns2"}, {Name{"xmlns", "tag"}, "ns3"}}},
+	CharData([]byte("\n  ")),
+	StartElement{Name{"ns2", "hello"}, []Attr{{Name{"", "lang"}, "en"}}},
+	CharData([]byte("World <>'\" 白鵬翔")),
+	EndElement{Name{"ns2", "hello"}},
+	CharData([]byte("\n  ")),
+	StartElement{Name{"ns2", "goodbye"}, nil},
+	EndElement{Name{"ns2", "goodbye"}},
+	CharData([]byte("\n  ")),
+	StartElement{Name{"ns2", "outer"}, []Attr{{Name{"ns1", "attr"}, "value"}, {Name{"xmlns", "tag"}, "ns4"}}},
+	CharData([]byte("\n    ")),
+	StartElement{Name{"ns2", "inner"}, nil},
+	EndElement{Name{"ns2", "inner"}},
+	CharData([]byte("\n  ")),
+	EndElement{Name{"ns2", "outer"}},
+	CharData([]byte("\n  ")),
+	StartElement{Name{"ns3", "name"}, nil},
+	CharData([]byte("\n    ")),
+	CharData([]byte("Some text here.")),
+	CharData([]byte("\n  ")),
+	EndElement{Name{"ns3", "name"}},
+	CharData([]byte("\n")),
+	EndElement{Name{"ns2", "body"}},
+	Comment([]byte(" missing final newline ")),
+}
+
+const testInputAltEncoding = `
+<?xml version="1.0" encoding="x-testing-uppercase"?>
+<TAG>VALUE</TAG>`
+
+var rawTokensAltEncoding = []Token{
+	CharData([]byte("\n")),
+	ProcInst{"xml", []byte(`version="1.0" encoding="x-testing-uppercase"`)},
+	CharData([]byte("\n")),
+	StartElement{Name{"", "tag"}, nil},
+	CharData([]byte("value")),
+	EndElement{Name{"", "tag"}},
+}
+
+var xmlInput = []string{
+	// unexpected EOF cases
+	"<",
+	"<t",
+	"<t ",
+	"<t/",
+	"<!",
+	"<!-",
+	"<!--",
+	"<!--c-",
+	"<!--c--",
+	"<!d",
+	"<t></",
+	"<t></t",
+	"<?",
+	"<?p",
+	"<t a",
+	"<t a=",
+	"<t a='",
+	"<t a=''",
+	"<t/><![",
+	"<t/><![C",
+	"<t/><![CDATA[d",
+	"<t/><![CDATA[d]",
+	"<t/><![CDATA[d]]",
+
+	// other Syntax errors
+	"<>",
+	"<t/a",
+	"<0 />",
+	"<?0 >",
+	//	"<!0 >",	// let the Token() caller handle
+	"</0>",
+	"<t 0=''>",
+	"<t a='&'>",
+	"<t a='<'>",
+	"<t>&nbspc;</t>",
+	"<t a>",
+	"<t a=>",
+	"<t a=v>",
+	//	"<![CDATA[d]]>",	// let the Token() caller handle
+	"<t></e>",
+	"<t></>",
+	"<t></t!",
+	"<t>cdata]]></t>",
+}
+
+type stringReader struct {
+	s   string
+	off int
+}
+
+func (r *stringReader) Read(b []byte) (n int, err error) {
+	if r.off >= len(r.s) {
+		return 0, io.EOF
+	}
+	for r.off < len(r.s) && n < len(b) {
+		b[n] = r.s[r.off]
+		n++
+		r.off++
+	}
+	return
+}
+
+func (r *stringReader) ReadByte() (b byte, err error) {
+	if r.off >= len(r.s) {
+		return 0, io.EOF
+	}
+	b = r.s[r.off]
+	r.off++
+	return
+}
+
+func StringReader(s string) io.Reader { return &stringReader{s, 0} }
+
+func TestRawToken(t *testing.T) {
+	p := NewParser(StringReader(testInput))
+	testRawToken(t, p, rawTokens)
+}
+
+type downCaser struct {
+	t *testing.T
+	r io.ByteReader
+}
+
+func (d *downCaser) ReadByte() (c byte, err error) {
+	c, err = d.r.ReadByte()
+	if c >= 'A' && c <= 'Z' {
+		c += 'a' - 'A'
+	}
+	return
+}
+
+func (d *downCaser) Read(p []byte) (int, error) {
+	d.t.Fatalf("unexpected Read call on downCaser reader")
+	return 0, os.EINVAL
+}
+
+func TestRawTokenAltEncoding(t *testing.T) {
+	sawEncoding := ""
+	p := NewParser(StringReader(testInputAltEncoding))
+	p.CharsetReader = func(charset string, input io.Reader) (io.Reader, error) {
+		sawEncoding = charset
+		if charset != "x-testing-uppercase" {
+			t.Fatalf("unexpected charset %q", charset)
+		}
+		return &downCaser{t, input.(io.ByteReader)}, nil
+	}
+	testRawToken(t, p, rawTokensAltEncoding)
+}
+
+func TestRawTokenAltEncodingNoConverter(t *testing.T) {
+	p := NewParser(StringReader(testInputAltEncoding))
+	token, err := p.RawToken()
+	if token == nil {
+		t.Fatalf("expected a token on first RawToken call")
+	}
+	if err != nil {
+		t.Fatal(err)
+	}
+	token, err = p.RawToken()
+	if token != nil {
+		t.Errorf("expected a nil token; got %#v", token)
+	}
+	if err == nil {
+		t.Fatalf("expected an error on second RawToken call")
+	}
+	const encoding = "x-testing-uppercase"
+	if !strings.Contains(err.Error(), encoding) {
+		t.Errorf("expected error to contain %q; got error: %v",
+			encoding, err)
+	}
+}
+
+func testRawToken(t *testing.T, p *Parser, rawTokens []Token) {
+	for i, want := range rawTokens {
+		have, err := p.RawToken()
+		if err != nil {
+			t.Fatalf("token %d: unexpected error: %s", i, err)
+		}
+		if !reflect.DeepEqual(have, want) {
+			t.Errorf("token %d = %#v want %#v", i, have, want)
+		}
+	}
+}
+
+// Ensure that directives (specifically !DOCTYPE) include the complete
+// text of any nested directives, noting that < and > do not change
+// nesting depth if they are in single or double quotes.
+
+var nestedDirectivesInput = `
+<!DOCTYPE [<!ENTITY rdf "http://www.w3.org/1999/02/22-rdf-syntax-ns#">]>
+<!DOCTYPE [<!ENTITY xlt ">">]>
+<!DOCTYPE [<!ENTITY xlt "<">]>
+<!DOCTYPE [<!ENTITY xlt '>'>]>
+<!DOCTYPE [<!ENTITY xlt '<'>]>
+<!DOCTYPE [<!ENTITY xlt '">'>]>
+<!DOCTYPE [<!ENTITY xlt "'<">]>
+`
+
+var nestedDirectivesTokens = []Token{
+	CharData([]byte("\n")),
+	Directive([]byte(`DOCTYPE [<!ENTITY rdf "http://www.w3.org/1999/02/22-rdf-syntax-ns#">]`)),
+	CharData([]byte("\n")),
+	Directive([]byte(`DOCTYPE [<!ENTITY xlt ">">]`)),
+	CharData([]byte("\n")),
+	Directive([]byte(`DOCTYPE [<!ENTITY xlt "<">]`)),
+	CharData([]byte("\n")),
+	Directive([]byte(`DOCTYPE [<!ENTITY xlt '>'>]`)),
+	CharData([]byte("\n")),
+	Directive([]byte(`DOCTYPE [<!ENTITY xlt '<'>]`)),
+	CharData([]byte("\n")),
+	Directive([]byte(`DOCTYPE [<!ENTITY xlt '">'>]`)),
+	CharData([]byte("\n")),
+	Directive([]byte(`DOCTYPE [<!ENTITY xlt "'<">]`)),
+	CharData([]byte("\n")),
+}
+
+func TestNestedDirectives(t *testing.T) {
+	p := NewParser(StringReader(nestedDirectivesInput))
+
+	for i, want := range nestedDirectivesTokens {
+		have, err := p.Token()
+		if err != nil {
+			t.Fatalf("token %d: unexpected error: %s", i, err)
+		}
+		if !reflect.DeepEqual(have, want) {
+			t.Errorf("token %d = %#v want %#v", i, have, want)
+		}
+	}
+}
+
+func TestToken(t *testing.T) {
+	p := NewParser(StringReader(testInput))
+
+	for i, want := range cookedTokens {
+		have, err := p.Token()
+		if err != nil {
+			t.Fatalf("token %d: unexpected error: %s", i, err)
+		}
+		if !reflect.DeepEqual(have, want) {
+			t.Errorf("token %d = %#v want %#v", i, have, want)
+		}
+	}
+}
+
+func TestSyntax(t *testing.T) {
+	for i := range xmlInput {
+		p := NewParser(StringReader(xmlInput[i]))
+		var err error
+		for _, err = p.Token(); err == nil; _, err = p.Token() {
+		}
+		if _, ok := err.(*SyntaxError); !ok {
+			t.Fatalf(`xmlInput "%s": expected SyntaxError not received`, xmlInput[i])
+		}
+	}
+}
+
+type allScalars struct {
+	True1     bool
+	True2     bool
+	False1    bool
+	False2    bool
+	Int       int
+	Int8      int8
+	Int16     int16
+	Int32     int32
+	Int64     int64
+	Uint      int
+	Uint8     uint8
+	Uint16    uint16
+	Uint32    uint32
+	Uint64    uint64
+	Uintptr   uintptr
+	Float32   float32
+	Float64   float64
+	String    string
+	PtrString *string
+}
+
+var all = allScalars{
+	True1:     true,
+	True2:     true,
+	False1:    false,
+	False2:    false,
+	Int:       1,
+	Int8:      -2,
+	Int16:     3,
+	Int32:     -4,
+	Int64:     5,
+	Uint:      6,
+	Uint8:     7,
+	Uint16:    8,
+	Uint32:    9,
+	Uint64:    10,
+	Uintptr:   11,
+	Float32:   13.0,
+	Float64:   14.0,
+	String:    "15",
+	PtrString: &sixteen,
+}
+
+var sixteen = "16"
+
+const testScalarsInput = `<allscalars>
+	<true1>true</true1>
+	<true2>1</true2>
+	<false1>false</false1>
+	<false2>0</false2>
+	<int>1</int>
+	<int8>-2</int8>
+	<int16>3</int16>
+	<int32>-4</int32>
+	<int64>5</int64>
+	<uint>6</uint>
+	<uint8>7</uint8>
+	<uint16>8</uint16>
+	<uint32>9</uint32>
+	<uint64>10</uint64>
+	<uintptr>11</uintptr>
+	<float>12.0</float>
+	<float32>13.0</float32>
+	<float64>14.0</float64>
+	<string>15</string>
+	<ptrstring>16</ptrstring>
+</allscalars>`
+
+func TestAllScalars(t *testing.T) {
+	var a allScalars
+	buf := bytes.NewBufferString(testScalarsInput)
+	err := Unmarshal(buf, &a)
+
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !reflect.DeepEqual(a, all) {
+		t.Errorf("have %+v want %+v", a, all)
+	}
+}
+
+type item struct {
+	Field_a string
+}
+
+func TestIssue569(t *testing.T) {
+	data := `<item><field_a>abcd</field_a></item>`
+	var i item
+	buf := bytes.NewBufferString(data)
+	err := Unmarshal(buf, &i)
+
+	if err != nil || i.Field_a != "abcd" {
+		t.Fatal("Expecting abcd")
+	}
+}
+
+func TestUnquotedAttrs(t *testing.T) {
+	data := "<tag attr=azAZ09:-_\t>"
+	p := NewParser(StringReader(data))
+	p.Strict = false
+	token, err := p.Token()
+	if _, ok := err.(*SyntaxError); ok {
+		t.Errorf("Unexpected error: %v", err)
+	}
+	if token.(StartElement).Name.Local != "tag" {
+		t.Errorf("Unexpected tag name: %v", token.(StartElement).Name.Local)
+	}
+	attr := token.(StartElement).Attr[0]
+	if attr.Value != "azAZ09:-_" {
+		t.Errorf("Unexpected attribute value: %v", attr.Value)
+	}
+	if attr.Name.Local != "attr" {
+		t.Errorf("Unexpected attribute name: %v", attr.Name.Local)
+	}
+}
+
+func TestValuelessAttrs(t *testing.T) {
+	tests := [][3]string{
+		{"<p nowrap>", "p", "nowrap"},
+		{"<p nowrap >", "p", "nowrap"},
+		{"<input checked/>", "input", "checked"},
+		{"<input checked />", "input", "checked"},
+	}
+	for _, test := range tests {
+		p := NewParser(StringReader(test[0]))
+		p.Strict = false
+		token, err := p.Token()
+		if _, ok := err.(*SyntaxError); ok {
+			t.Errorf("Unexpected error: %v", err)
+		}
+		if token.(StartElement).Name.Local != test[1] {
+			t.Errorf("Unexpected tag name: %v", token.(StartElement).Name.Local)
+		}
+		attr := token.(StartElement).Attr[0]
+		if attr.Value != test[2] {
+			t.Errorf("Unexpected attribute value: %v", attr.Value)
+		}
+		if attr.Name.Local != test[2] {
+			t.Errorf("Unexpected attribute name: %v", attr.Name.Local)
+		}
+	}
+}
+
+func TestCopyTokenCharData(t *testing.T) {
+	data := []byte("same data")
+	var tok1 Token = CharData(data)
+	tok2 := CopyToken(tok1)
+	if !reflect.DeepEqual(tok1, tok2) {
+		t.Error("CopyToken(CharData) != CharData")
+	}
+	data[1] = 'o'
+	if reflect.DeepEqual(tok1, tok2) {
+		t.Error("CopyToken(CharData) uses same buffer.")
+	}
+}
+
+func TestCopyTokenStartElement(t *testing.T) {
+	elt := StartElement{Name{"", "hello"}, []Attr{{Name{"", "lang"}, "en"}}}
+	var tok1 Token = elt
+	tok2 := CopyToken(tok1)
+	if !reflect.DeepEqual(tok1, tok2) {
+		t.Error("CopyToken(StartElement) != StartElement")
+	}
+	elt.Attr[0] = Attr{Name{"", "lang"}, "de"}
+	if reflect.DeepEqual(tok1, tok2) {
+		t.Error("CopyToken(CharData) uses same buffer.")
+	}
+}
+
+func TestSyntaxErrorLineNum(t *testing.T) {
+	testInput := "<P>Foo<P>\n\n<P>Bar</>\n"
+	p := NewParser(StringReader(testInput))
+	var err error
+	for _, err = p.Token(); err == nil; _, err = p.Token() {
+	}
+	synerr, ok := err.(*SyntaxError)
+	if !ok {
+		t.Error("Expected SyntaxError.")
+	}
+	if synerr.Line != 3 {
+		t.Error("SyntaxError didn't have correct line number.")
+	}
+}
+
+func TestTrailingRawToken(t *testing.T) {
+	input := `<FOO></FOO>  `
+	p := NewParser(StringReader(input))
+	var err error
+	for _, err = p.RawToken(); err == nil; _, err = p.RawToken() {
+	}
+	if err != io.EOF {
+		t.Fatalf("p.RawToken() = _, %v, want _, io.EOF", err)
+	}
+}
+
+func TestTrailingToken(t *testing.T) {
+	input := `<FOO></FOO>  `
+	p := NewParser(StringReader(input))
+	var err error
+	for _, err = p.Token(); err == nil; _, err = p.Token() {
+	}
+	if err != io.EOF {
+		t.Fatalf("p.Token() = _, %v, want _, io.EOF", err)
+	}
+}
+
+func TestEntityInsideCDATA(t *testing.T) {
+	input := `<test><![CDATA[ &val=foo ]]></test>`
+	p := NewParser(StringReader(input))
+	var err error
+	for _, err = p.Token(); err == nil; _, err = p.Token() {
+	}
+	if err != io.EOF {
+		t.Fatalf("p.Token() = _, %v, want _, io.EOF", err)
+	}
+}
+
+// The last three tests (respectively one for characters in attribute
+// names and two for character entities) pass not because of code
+// changed for issue 1259, but instead pass with the given messages
+// from other parts of xml.Parser.  I provide these to note the
+// current behavior of situations where one might think that character
+// range checking would detect the error, but it does not in fact.
+
+var characterTests = []struct {
+	in  string
+	err string
+}{
+	{"\x12<doc/>", "illegal character code U+0012"},
+	{"<?xml version=\"1.0\"?>\x0b<doc/>", "illegal character code U+000B"},
+	{"\xef\xbf\xbe<doc/>", "illegal character code U+FFFE"},
+	{"<?xml version=\"1.0\"?><doc>\r\n<hiya/>\x07<toots/></doc>", "illegal character code U+0007"},
+	{"<?xml version=\"1.0\"?><doc \x12='value'>what's up</doc>", "expected attribute name in element"},
+	{"<doc>&\x01;</doc>", "invalid character entity &;"},
+	{"<doc>&\xef\xbf\xbe;</doc>", "invalid character entity &;"},
+}
+
+func TestDisallowedCharacters(t *testing.T) {
+
+	for i, tt := range characterTests {
+		p := NewParser(StringReader(tt.in))
+		var err error
+
+		for err == nil {
+			_, err = p.Token()
+		}
+		synerr, ok := err.(*SyntaxError)
+		if !ok {
+			t.Fatalf("input %d p.Token() = _, %v, want _, *SyntaxError", i, err)
+		}
+		if synerr.Msg != tt.err {
+			t.Fatalf("input %d synerr.Msg wrong: want '%s', got '%s'", i, tt.err, synerr.Msg)
+		}
+	}
+}
+
+type procInstEncodingTest struct {
+	expect, got string
+}
+
+var procInstTests = []struct {
+	input, expect string
+}{
+	{`version="1.0" encoding="utf-8"`, "utf-8"},
+	{`version="1.0" encoding='utf-8'`, "utf-8"},
+	{`version="1.0" encoding='utf-8' `, "utf-8"},
+	{`version="1.0" encoding=utf-8`, ""},
+	{`encoding="FOO" `, "FOO"},
+}
+
+func TestProcInstEncoding(t *testing.T) {
+	for _, test := range procInstTests {
+		got := procInstEncoding(test.input)
+		if got != test.expect {
+			t.Errorf("procInstEncoding(%q) = %q; want %q", test.input, got, test.expect)
+		}
+	}
+}