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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"
"time"
_ "unsafe" // For go:linkname
)
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 stat(name string) (mtime time.Time, size int64, err error) {
st, err := os.Stat(name)
if err != nil {
return time.Time{}, 0, err
}
return st.ModTime(), st.Size(), nil
}
// byteIndex is strings.IndexByte. It returns the index of the
// first instance of c in s, or -1 if c is not present in s.
// strings.IndexByte is implemented in runtime/asm_$GOARCH.s
//go:linkname byteIndex strings.IndexByte
func byteIndex(s string, c byte) int
// 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] = s[last:i]
n++
}
last = i + 1
}
}
if last < len(s) {
a[n] = 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.
// Returns number, characters consumed, success.
func dtoi(s string) (n int, i int, ok bool) {
n = 0
for i = 0; i < len(s) && '0' <= s[i] && s[i] <= '9'; i++ {
n = n*10 + int(s[i]-'0')
if n >= big {
return big, i, false
}
}
if i == 0 {
return 0, 0, false
}
return n, i, true
}
// Hexadecimal to integer.
// Returns number, characters consumed, success.
func xtoi(s string) (n int, i int, ok bool) {
n = 0
for i = 0; 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 == 0 {
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])
return byte(n), ok && ei == 2
}
// Convert integer to decimal string.
func itoa(val int) string {
if val < 0 {
return "-" + uitoa(uint(-val))
}
return uitoa(uint(val))
}
// Convert unsigned integer to decimal string.
func uitoa(val uint) string {
if val == 0 { // avoid string allocation
return "0"
}
var buf [20]byte // big enough for 64bit value base 10
i := len(buf) - 1
for val >= 10 {
q := val / 10
buf[i] = byte('0' + val - q*10)
i--
val = q
}
// val < 10
buf[i] = byte('0' + val)
return string(buf[i:])
}
// 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
}
// lowerASCIIBytes makes x ASCII lowercase in-place.
func lowerASCIIBytes(x []byte) {
for i, b := range x {
if 'A' <= b && b <= 'Z' {
x[i] += 'a' - 'A'
}
}
}
// lowerASCII returns the ASCII lowercase version of b.
func lowerASCII(b byte) byte {
if 'A' <= b && b <= 'Z' {
return b + ('a' - 'A')
}
return b
}
// trimSpace returns x without any leading or trailing ASCII whitespace.
func trimSpace(x []byte) []byte {
for len(x) > 0 && isSpace(x[0]) {
x = x[1:]
}
for len(x) > 0 && isSpace(x[len(x)-1]) {
x = x[:len(x)-1]
}
return x
}
// isSpace reports whether b is an ASCII space character.
func isSpace(b byte) bool {
return b == ' ' || b == '\t' || b == '\n' || b == '\r'
}
// removeComment returns line, removing any '#' byte and any following
// bytes.
func removeComment(line []byte) []byte {
if i := bytesIndexByte(line, '#'); i != -1 {
return line[:i]
}
return line
}
// foreachLine runs fn on each line of x.
// Each line (except for possibly the last) ends in '\n'.
// It returns the first non-nil error returned by fn.
func foreachLine(x []byte, fn func(line []byte) error) error {
for len(x) > 0 {
nl := bytesIndexByte(x, '\n')
if nl == -1 {
return fn(x)
}
line := x[:nl+1]
x = x[nl+1:]
if err := fn(line); err != nil {
return err
}
}
return nil
}
// foreachField runs fn on each non-empty run of non-space bytes in x.
// It returns the first non-nil error returned by fn.
func foreachField(x []byte, fn func(field []byte) error) error {
x = trimSpace(x)
for len(x) > 0 {
sp := bytesIndexByte(x, ' ')
if sp == -1 {
return fn(x)
}
if field := trimSpace(x[:sp]); len(field) > 0 {
if err := fn(field); err != nil {
return err
}
}
x = trimSpace(x[sp+1:])
}
return nil
}
// bytesIndexByte is bytes.IndexByte. It returns the index of the
// first instance of c in s, or -1 if c is not present in s.
// bytes.IndexByte is implemented in runtime/asm_$GOARCH.s
//go:linkname bytesIndexByte bytes.IndexByte
func bytesIndexByte(s []byte, c byte) int
// stringsHasSuffix is strings.HasSuffix. It reports whether s ends in
// suffix.
func stringsHasSuffix(s, suffix string) bool {
return len(s) >= len(suffix) && s[len(s)-len(suffix):] == suffix
}
// stringsHasSuffixFold reports whether s ends in suffix,
// ASCII-case-insensitively.
func stringsHasSuffixFold(s, suffix string) bool {
return len(s) >= len(suffix) && stringsEqualFold(s[len(s)-len(suffix):], suffix)
}
// stringsHasPrefix is strings.HasPrefix. It reports whether s begins with prefix.
func stringsHasPrefix(s, prefix string) bool {
return len(s) >= len(prefix) && s[:len(prefix)] == prefix
}
// stringsEqualFold is strings.EqualFold, ASCII only. It reports whether s and t
// are equal, ASCII-case-insensitively.
func stringsEqualFold(s, t string) bool {
if len(s) != len(t) {
return false
}
for i := 0; i < len(s); i++ {
if lowerASCII(s[i]) != lowerASCII(t[i]) {
return false
}
}
return true
}
func readFull(r io.Reader) (all []byte, err error) {
buf := make([]byte, 1024)
for {
n, err := r.Read(buf)
all = append(all, buf[:n]...)
if err == io.EOF {
return all, nil
}
if err != nil {
return nil, err
}
}
}
// goDebugString returns the value of the named GODEBUG key.
// GODEBUG is of the form "key=val,key2=val2"
func goDebugString(key string) string {
s := os.Getenv("GODEBUG")
for i := 0; i < len(s)-len(key)-1; i++ {
if i > 0 && s[i-1] != ',' {
continue
}
afterKey := s[i+len(key):]
if afterKey[0] != '=' || s[i:i+len(key)] != key {
continue
}
val := afterKey[1:]
for i, b := range val {
if b == ',' {
return val[:i]
}
}
return val
}
return ""
}