Update Go library to last weekly.

From-SVN: r180552

3 files changed, 109 insertions, 10 deletions

diff --git a/libgo/go/bytes/buffer.go b/libgo/go/bytes/buffer.go
index 5de86105d05..975031bfa4f 100644
--- a/libgo/go/bytes/buffer.go
+++ b/libgo/go/bytes/buffer.go
@@ -336,13 +336,18 @@ func (b *Buffer) ReadString(delim byte) (line string, err os.Error) {
 
 // NewBuffer creates and initializes a new Buffer using buf as its initial
 // contents.  It is intended to prepare a Buffer to read existing data.  It
-// can also be used to size the internal buffer for writing.  To do that,
+// can also be used to size the internal buffer for writing. To do that,
 // buf should have the desired capacity but a length of zero.
+//
+// In most cases, new(Buffer) (or just declaring a Buffer variable) is
+// preferable to NewBuffer.  In particular, passing a non-empty buf to
+// NewBuffer and then writing to the Buffer will overwrite buf, not append to
+// it.
 func NewBuffer(buf []byte) *Buffer { return &Buffer{buf: buf} }
 
 // NewBufferString creates and initializes a new Buffer using string s as its
 // initial contents.  It is intended to prepare a buffer to read an existing
-// string.
+// string.  See the warnings about NewBuffer; similar issues apply here.
 func NewBufferString(s string) *Buffer {
 	return &Buffer{buf: []byte(s)}
 }
diff --git a/libgo/go/bytes/bytes.go b/libgo/go/bytes/bytes.go
index 5119fce949e..2fb456900a7 100644
--- a/libgo/go/bytes/bytes.go
+++ b/libgo/go/bytes/bytes.go
@@ -572,13 +572,18 @@ func Runes(s []byte) []int {
 // non-overlapping instances of old replaced by new.
 // If n < 0, there is no limit on the number of replacements.
 func Replace(s, old, new []byte, n int) []byte {
-	if n == 0 {
-		return s // avoid allocation
-	}
-	// Compute number of replacements.
-	if m := Count(s, old); m == 0 {
-		return s // avoid allocation
-	} else if n <= 0 || m < n {
+	m := 0
+	if n != 0 {
+		// Compute number of replacements.
+		m = Count(s, old)
+	}
+	if m == 0 {
+		// Nothing to do. Just copy.
+		t := make([]byte, len(s))
+		copy(t, s)
+		return t
+	}
+	if n < 0 || m < n {
 		n = m
 	}
 
@@ -603,3 +608,58 @@ func Replace(s, old, new []byte, n int) []byte {
 	w += copy(t[w:], s[start:])
 	return t[0:w]
 }
+
+// EqualFold reports whether s and t, interpreted as UTF-8 strings,
+// are equal under Unicode case-folding.
+func EqualFold(s, t []byte) bool {
+	for len(s) != 0 && len(t) != 0 {
+		// Extract first rune from each.
+		var sr, tr int
+		if s[0] < utf8.RuneSelf {
+			sr, s = int(s[0]), s[1:]
+		} else {
+			r, size := utf8.DecodeRune(s)
+			sr, s = r, s[size:]
+		}
+		if t[0] < utf8.RuneSelf {
+			tr, t = int(t[0]), t[1:]
+		} else {
+			r, size := utf8.DecodeRune(t)
+			tr, t = r, t[size:]
+		}
+
+		// If they match, keep going; if not, return false.
+
+		// Easy case.
+		if tr == sr {
+			continue
+		}
+
+		// Make sr < tr to simplify what follows.
+		if tr < sr {
+			tr, sr = sr, tr
+		}
+		// Fast check for ASCII.
+		if tr < utf8.RuneSelf && 'A' <= sr && sr <= 'Z' {
+			// ASCII, and sr is upper case.  tr must be lower case.
+			if tr == sr+'a'-'A' {
+				continue
+			}
+			return false
+		}
+
+		// General case.  SimpleFold(x) returns the next equivalent rune > x
+		// or wraps around to smaller values.
+		r := unicode.SimpleFold(sr)
+		for r != sr && r < tr {
+			r = unicode.SimpleFold(r)
+		}
+		if r == tr {
+			continue
+		}
+		return false
+	}
+
+	// One string is empty.  Are both?
+	return len(s) == len(t)
+}
diff --git a/libgo/go/bytes/bytes_test.go b/libgo/go/bytes/bytes_test.go
index 9444358a858..ce3f37e4de2 100644
--- a/libgo/go/bytes/bytes_test.go
+++ b/libgo/go/bytes/bytes_test.go
@@ -829,9 +829,15 @@ var ReplaceTests = []ReplaceTest{
 
 func TestReplace(t *testing.T) {
 	for _, tt := range ReplaceTests {
-		if s := string(Replace([]byte(tt.in), []byte(tt.old), []byte(tt.new), tt.n)); s != tt.out {
+		in := append([]byte(tt.in), "<spare>"...)
+		in = in[:len(tt.in)]
+		out := Replace(in, []byte(tt.old), []byte(tt.new), tt.n)
+		if s := string(out); s != tt.out {
 			t.Errorf("Replace(%q, %q, %q, %d) = %q, want %q", tt.in, tt.old, tt.new, tt.n, s, tt.out)
 		}
+		if cap(in) == cap(out) && &in[:1][0] == &out[:1][0] {
+			t.Errorf("Replace(%q, %q, %q, %d) didn't copy", tt.in, tt.old, tt.new, tt.n)
+		}
 	}
 }
 
@@ -856,3 +862,31 @@ func TestTitle(t *testing.T) {
 		}
 	}
 }
+
+var EqualFoldTests = []struct {
+	s, t string
+	out  bool
+}{
+	{"abc", "abc", true},
+	{"ABcd", "ABcd", true},
+	{"123abc", "123ABC", true},
+	{"αβδ", "ΑΒΔ", true},
+	{"abc", "xyz", false},
+	{"abc", "XYZ", false},
+	{"abcdefghijk", "abcdefghijX", false},
+	{"abcdefghijk", "abcdefghij\u212A", true},
+	{"abcdefghijK", "abcdefghij\u212A", true},
+	{"abcdefghijkz", "abcdefghij\u212Ay", false},
+	{"abcdefghijKz", "abcdefghij\u212Ay", false},
+}
+
+func TestEqualFold(t *testing.T) {
+	for _, tt := range EqualFoldTests {
+		if out := EqualFold([]byte(tt.s), []byte(tt.t)); out != tt.out {
+			t.Errorf("EqualFold(%#q, %#q) = %v, want %v", tt.s, tt.t, out, tt.out)
+		}
+		if out := EqualFold([]byte(tt.t), []byte(tt.s)); out != tt.out {
+			t.Errorf("EqualFold(%#q, %#q) = %v, want %v", tt.t, tt.s, out, tt.out)
+		}
+	}
+}