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// 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.
// Simple file i/o and string manipulation, to avoid
// depending on strconv and bufio and strings.
package net
import (
"io"
"os"
)
type file struct {
file *os.File
data []byte
atEOF bool
}
func (f *file) close() { f.file.Close() }
func (f *file) getLineFromData() (s string, ok bool) {
data := f.data
i := 0
for i = 0; i < len(data); i++ {
if data[i] == '\n' {
s = string(data[0:i])
ok = true
// move data
i++
n := len(data) - i
copy(data[0:], data[i:])
f.data = data[0:n]
return
}
}
if f.atEOF && len(f.data) > 0 {
// EOF, return all we have
s = string(data)
f.data = f.data[0:0]
ok = true
}
return
}
func (f *file) readLine() (s string, ok bool) {
if s, ok = f.getLineFromData(); ok {
return
}
if len(f.data) < cap(f.data) {
ln := len(f.data)
n, err := io.ReadFull(f.file, f.data[ln:cap(f.data)])
if n >= 0 {
f.data = f.data[0 : ln+n]
}
if err == io.EOF || err == io.ErrUnexpectedEOF {
f.atEOF = true
}
}
s, ok = f.getLineFromData()
return
}
func open(name string) (*file, error) {
fd, err := os.Open(name)
if err != nil {
return nil, err
}
return &file{fd, make([]byte, 0, os.Getpagesize()), false}, nil
}
func byteIndex(s string, c byte) int {
for i := 0; i < len(s); i++ {
if s[i] == c {
return i
}
}
return -1
}
// Count occurrences in s of any bytes in t.
func countAnyByte(s string, t string) int {
n := 0
for i := 0; i < len(s); i++ {
if byteIndex(t, s[i]) >= 0 {
n++
}
}
return n
}
// Split s at any bytes in t.
func splitAtBytes(s string, t string) []string {
a := make([]string, 1+countAnyByte(s, t))
n := 0
last := 0
for i := 0; i < len(s); i++ {
if byteIndex(t, s[i]) >= 0 {
if last < i {
a[n] = string(s[last:i])
n++
}
last = i + 1
}
}
if last < len(s) {
a[n] = string(s[last:])
n++
}
return a[0:n]
}
func getFields(s string) []string { return splitAtBytes(s, " \r\t\n") }
// Bigger than we need, not too big to worry about overflow
const big = 0xFFFFFF
// Decimal to integer starting at &s[i0].
// Returns number, new offset, success.
func dtoi(s string, i0 int) (n int, i int, ok bool) {
n = 0
for i = i0; i < len(s) && '0' <= s[i] && s[i] <= '9'; i++ {
n = n*10 + int(s[i]-'0')
if n >= big {
return 0, i, false
}
}
if i == i0 {
return 0, i, false
}
return n, i, true
}
// Hexadecimal to integer starting at &s[i0].
// Returns number, new offset, success.
func xtoi(s string, i0 int) (n int, i int, ok bool) {
n = 0
for i = i0; i < len(s); i++ {
if '0' <= s[i] && s[i] <= '9' {
n *= 16
n += int(s[i] - '0')
} else if 'a' <= s[i] && s[i] <= 'f' {
n *= 16
n += int(s[i]-'a') + 10
} else if 'A' <= s[i] && s[i] <= 'F' {
n *= 16
n += int(s[i]-'A') + 10
} else {
break
}
if n >= big {
return 0, i, false
}
}
if i == i0 {
return 0, i, false
}
return n, i, true
}
// xtoi2 converts the next two hex digits of s into a byte.
// If s is longer than 2 bytes then the third byte must be e.
// If the first two bytes of s are not hex digits or the third byte
// does not match e, false is returned.
func xtoi2(s string, e byte) (byte, bool) {
if len(s) > 2 && s[2] != e {
return 0, false
}
n, ei, ok := xtoi(s[:2], 0)
return byte(n), ok && ei == 2
}
// Integer to decimal.
func itoa(i int) string {
var buf [30]byte
n := len(buf)
neg := false
if i < 0 {
i = -i
neg = true
}
ui := uint(i)
for ui > 0 || n == len(buf) {
n--
buf[n] = byte('0' + ui%10)
ui /= 10
}
if neg {
n--
buf[n] = '-'
}
return string(buf[n:])
}
// Convert i to decimal string.
func itod(i uint) string {
if i == 0 {
return "0"
}
// Assemble decimal in reverse order.
var b [32]byte
bp := len(b)
for ; i > 0; i /= 10 {
bp--
b[bp] = byte(i%10) + '0'
}
return string(b[bp:])
}
// Convert i to a hexadecimal string. Leading zeros are not printed.
func appendHex(dst []byte, i uint32) []byte {
if i == 0 {
return append(dst, '0')
}
for j := 7; j >= 0; j-- {
v := i >> uint(j*4)
if v > 0 {
dst = append(dst, hexDigit[v&0xf])
}
}
return dst
}
// Number of occurrences of b in s.
func count(s string, b byte) int {
n := 0
for i := 0; i < len(s); i++ {
if s[i] == b {
n++
}
}
return n
}
// Index of rightmost occurrence of b in s.
func last(s string, b byte) int {
i := len(s)
for i--; i >= 0; i-- {
if s[i] == b {
break
}
}
return i
}
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