mirror of
https://github.com/golang/go.git
synced 2025-12-08 06:10:04 +00:00
build: move package sources from src/pkg to src
Preparation was in CL 134570043. This CL contains only the effect of 'hg mv src/pkg/* src'. For more about the move, see golang.org/s/go14nopkg.
This commit is contained in:
Russ Cox
parent
220a6de47e
commit
c007ce824d
2097 changed files with 0 additions and 0 deletions
701
src/bytes/bytes.go
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701
src/bytes/bytes.go
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@ -0,0 +1,701 @@
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// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Package bytes implements functions for the manipulation of byte slices.
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// It is analogous to the facilities of the strings package.
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package bytes
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import (
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"unicode"
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"unicode/utf8"
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)
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func equalPortable(a, b []byte) bool {
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if len(a) != len(b) {
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return false
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}
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for i, c := range a {
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if c != b[i] {
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return false
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}
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}
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return true
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}
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// explode splits s into a slice of UTF-8 sequences, one per Unicode character (still slices of bytes),
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// up to a maximum of n byte slices. Invalid UTF-8 sequences are chopped into individual bytes.
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func explode(s []byte, n int) [][]byte {
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if n <= 0 {
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n = len(s)
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}
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a := make([][]byte, n)
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var size int
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na := 0
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for len(s) > 0 {
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if na+1 >= n {
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a[na] = s
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na++
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break
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}
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_, size = utf8.DecodeRune(s)
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a[na] = s[0:size]
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s = s[size:]
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na++
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}
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return a[0:na]
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}
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// Count counts the number of non-overlapping instances of sep in s.
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func Count(s, sep []byte) int {
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n := len(sep)
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if n == 0 {
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return utf8.RuneCount(s) + 1
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}
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if n > len(s) {
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return 0
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}
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count := 0
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c := sep[0]
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i := 0
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t := s[:len(s)-n+1]
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for i < len(t) {
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if t[i] != c {
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o := IndexByte(t[i:], c)
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if o < 0 {
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break
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}
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i += o
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}
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if n == 1 || Equal(s[i:i+n], sep) {
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count++
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i += n
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continue
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}
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i++
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}
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return count
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}
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// Contains reports whether subslice is within b.
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func Contains(b, subslice []byte) bool {
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return Index(b, subslice) != -1
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}
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// Index returns the index of the first instance of sep in s, or -1 if sep is not present in s.
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func Index(s, sep []byte) int {
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n := len(sep)
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if n == 0 {
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return 0
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}
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if n > len(s) {
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return -1
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}
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c := sep[0]
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if n == 1 {
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return IndexByte(s, c)
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}
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i := 0
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t := s[:len(s)-n+1]
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for i < len(t) {
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if t[i] != c {
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o := IndexByte(t[i:], c)
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if o < 0 {
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break
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}
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i += o
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}
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if Equal(s[i:i+n], sep) {
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return i
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}
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i++
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}
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return -1
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}
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func indexBytePortable(s []byte, c byte) int {
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for i, b := range s {
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if b == c {
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return i
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}
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}
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return -1
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}
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// LastIndex returns the index of the last instance of sep in s, or -1 if sep is not present in s.
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func LastIndex(s, sep []byte) int {
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n := len(sep)
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if n == 0 {
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return len(s)
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}
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c := sep[0]
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for i := len(s) - n; i >= 0; i-- {
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if s[i] == c && (n == 1 || Equal(s[i:i+n], sep)) {
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return i
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}
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}
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return -1
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}
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// IndexRune interprets s as a sequence of UTF-8-encoded Unicode code points.
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// It returns the byte index of the first occurrence in s of the given rune.
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// It returns -1 if rune is not present in s.
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func IndexRune(s []byte, r rune) int {
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for i := 0; i < len(s); {
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r1, size := utf8.DecodeRune(s[i:])
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if r == r1 {
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return i
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}
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i += size
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}
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return -1
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}
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// IndexAny interprets s as a sequence of UTF-8-encoded Unicode code points.
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// It returns the byte index of the first occurrence in s of any of the Unicode
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// code points in chars. It returns -1 if chars is empty or if there is no code
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// point in common.
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func IndexAny(s []byte, chars string) int {
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if len(chars) > 0 {
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var r rune
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var width int
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for i := 0; i < len(s); i += width {
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r = rune(s[i])
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if r < utf8.RuneSelf {
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width = 1
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} else {
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r, width = utf8.DecodeRune(s[i:])
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}
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for _, ch := range chars {
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if r == ch {
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return i
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}
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}
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}
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}
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return -1
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}
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// LastIndexAny interprets s as a sequence of UTF-8-encoded Unicode code
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// points. It returns the byte index of the last occurrence in s of any of
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// the Unicode code points in chars. It returns -1 if chars is empty or if
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// there is no code point in common.
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func LastIndexAny(s []byte, chars string) int {
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if len(chars) > 0 {
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for i := len(s); i > 0; {
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r, size := utf8.DecodeLastRune(s[0:i])
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i -= size
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for _, ch := range chars {
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if r == ch {
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return i
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}
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}
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}
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}
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return -1
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}
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// Generic split: splits after each instance of sep,
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// including sepSave bytes of sep in the subslices.
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func genSplit(s, sep []byte, sepSave, n int) [][]byte {
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if n == 0 {
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return nil
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}
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if len(sep) == 0 {
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return explode(s, n)
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}
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if n < 0 {
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n = Count(s, sep) + 1
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}
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c := sep[0]
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start := 0
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a := make([][]byte, n)
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na := 0
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for i := 0; i+len(sep) <= len(s) && na+1 < n; i++ {
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if s[i] == c && (len(sep) == 1 || Equal(s[i:i+len(sep)], sep)) {
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a[na] = s[start : i+sepSave]
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na++
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start = i + len(sep)
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i += len(sep) - 1
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}
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}
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a[na] = s[start:]
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return a[0 : na+1]
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}
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// SplitN slices s into subslices separated by sep and returns a slice of
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// the subslices between those separators.
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// If sep is empty, SplitN splits after each UTF-8 sequence.
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// The count determines the number of subslices to return:
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// n > 0: at most n subslices; the last subslice will be the unsplit remainder.
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// n == 0: the result is nil (zero subslices)
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// n < 0: all subslices
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func SplitN(s, sep []byte, n int) [][]byte { return genSplit(s, sep, 0, n) }
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// SplitAfterN slices s into subslices after each instance of sep and
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// returns a slice of those subslices.
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// If sep is empty, SplitAfterN splits after each UTF-8 sequence.
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// The count determines the number of subslices to return:
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// n > 0: at most n subslices; the last subslice will be the unsplit remainder.
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// n == 0: the result is nil (zero subslices)
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// n < 0: all subslices
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func SplitAfterN(s, sep []byte, n int) [][]byte {
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return genSplit(s, sep, len(sep), n)
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}
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// Split slices s into all subslices separated by sep and returns a slice of
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// the subslices between those separators.
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// If sep is empty, Split splits after each UTF-8 sequence.
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// It is equivalent to SplitN with a count of -1.
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func Split(s, sep []byte) [][]byte { return genSplit(s, sep, 0, -1) }
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// SplitAfter slices s into all subslices after each instance of sep and
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// returns a slice of those subslices.
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// If sep is empty, SplitAfter splits after each UTF-8 sequence.
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// It is equivalent to SplitAfterN with a count of -1.
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func SplitAfter(s, sep []byte) [][]byte {
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return genSplit(s, sep, len(sep), -1)
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}
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// Fields splits the slice s around each instance of one or more consecutive white space
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// characters, returning a slice of subslices of s or an empty list if s contains only white space.
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func Fields(s []byte) [][]byte {
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return FieldsFunc(s, unicode.IsSpace)
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}
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// FieldsFunc interprets s as a sequence of UTF-8-encoded Unicode code points.
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// It splits the slice s at each run of code points c satisfying f(c) and
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// returns a slice of subslices of s. If all code points in s satisfy f(c), or
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// len(s) == 0, an empty slice is returned.
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func FieldsFunc(s []byte, f func(rune) bool) [][]byte {
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n := 0
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inField := false
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for i := 0; i < len(s); {
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r, size := utf8.DecodeRune(s[i:])
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wasInField := inField
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inField = !f(r)
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if inField && !wasInField {
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n++
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}
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i += size
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}
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a := make([][]byte, n)
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na := 0
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fieldStart := -1
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for i := 0; i <= len(s) && na < n; {
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r, size := utf8.DecodeRune(s[i:])
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if fieldStart < 0 && size > 0 && !f(r) {
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fieldStart = i
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i += size
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continue
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}
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if fieldStart >= 0 && (size == 0 || f(r)) {
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a[na] = s[fieldStart:i]
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na++
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fieldStart = -1
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}
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if size == 0 {
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break
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}
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i += size
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}
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return a[0:na]
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}
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// Join concatenates the elements of s to create a new byte slice. The separator
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// sep is placed between elements in the resulting slice.
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func Join(s [][]byte, sep []byte) []byte {
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if len(s) == 0 {
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return []byte{}
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}
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if len(s) == 1 {
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// Just return a copy.
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return append([]byte(nil), s[0]...)
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}
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n := len(sep) * (len(s) - 1)
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for _, v := range s {
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n += len(v)
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}
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b := make([]byte, n)
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bp := copy(b, s[0])
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for _, v := range s[1:] {
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bp += copy(b[bp:], sep)
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bp += copy(b[bp:], v)
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}
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return b
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}
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// HasPrefix tests whether the byte slice s begins with prefix.
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func HasPrefix(s, prefix []byte) bool {
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return len(s) >= len(prefix) && Equal(s[0:len(prefix)], prefix)
|
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}
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|
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// HasSuffix tests whether the byte slice s ends with suffix.
|
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func HasSuffix(s, suffix []byte) bool {
|
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return len(s) >= len(suffix) && Equal(s[len(s)-len(suffix):], suffix)
|
||||
}
|
||||
|
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// Map returns a copy of the byte slice s with all its characters modified
|
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// according to the mapping function. If mapping returns a negative value, the character is
|
||||
// dropped from the string with no replacement. The characters in s and the
|
||||
// output are interpreted as UTF-8-encoded Unicode code points.
|
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func Map(mapping func(r rune) rune, s []byte) []byte {
|
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// In the worst case, the slice can grow when mapped, making
|
||||
// things unpleasant. But it's so rare we barge in assuming it's
|
||||
// fine. It could also shrink but that falls out naturally.
|
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maxbytes := len(s) // length of b
|
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nbytes := 0 // number of bytes encoded in b
|
||||
b := make([]byte, maxbytes)
|
||||
for i := 0; i < len(s); {
|
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wid := 1
|
||||
r := rune(s[i])
|
||||
if r >= utf8.RuneSelf {
|
||||
r, wid = utf8.DecodeRune(s[i:])
|
||||
}
|
||||
r = mapping(r)
|
||||
if r >= 0 {
|
||||
rl := utf8.RuneLen(r)
|
||||
if rl < 0 {
|
||||
rl = len(string(utf8.RuneError))
|
||||
}
|
||||
if nbytes+rl > maxbytes {
|
||||
// Grow the buffer.
|
||||
maxbytes = maxbytes*2 + utf8.UTFMax
|
||||
nb := make([]byte, maxbytes)
|
||||
copy(nb, b[0:nbytes])
|
||||
b = nb
|
||||
}
|
||||
nbytes += utf8.EncodeRune(b[nbytes:maxbytes], r)
|
||||
}
|
||||
i += wid
|
||||
}
|
||||
return b[0:nbytes]
|
||||
}
|
||||
|
||||
// Repeat returns a new byte slice consisting of count copies of b.
|
||||
func Repeat(b []byte, count int) []byte {
|
||||
nb := make([]byte, len(b)*count)
|
||||
bp := copy(nb, b)
|
||||
for bp < len(nb) {
|
||||
copy(nb[bp:], nb[:bp])
|
||||
bp *= 2
|
||||
}
|
||||
return nb
|
||||
}
|
||||
|
||||
// ToUpper returns a copy of the byte slice s with all Unicode letters mapped to their upper case.
|
||||
func ToUpper(s []byte) []byte { return Map(unicode.ToUpper, s) }
|
||||
|
||||
// ToLower returns a copy of the byte slice s with all Unicode letters mapped to their lower case.
|
||||
func ToLower(s []byte) []byte { return Map(unicode.ToLower, s) }
|
||||
|
||||
// ToTitle returns a copy of the byte slice s with all Unicode letters mapped to their title case.
|
||||
func ToTitle(s []byte) []byte { return Map(unicode.ToTitle, s) }
|
||||
|
||||
// ToUpperSpecial returns a copy of the byte slice s with all Unicode letters mapped to their
|
||||
// upper case, giving priority to the special casing rules.
|
||||
func ToUpperSpecial(_case unicode.SpecialCase, s []byte) []byte {
|
||||
return Map(func(r rune) rune { return _case.ToUpper(r) }, s)
|
||||
}
|
||||
|
||||
// ToLowerSpecial returns a copy of the byte slice s with all Unicode letters mapped to their
|
||||
// lower case, giving priority to the special casing rules.
|
||||
func ToLowerSpecial(_case unicode.SpecialCase, s []byte) []byte {
|
||||
return Map(func(r rune) rune { return _case.ToLower(r) }, s)
|
||||
}
|
||||
|
||||
// ToTitleSpecial returns a copy of the byte slice s with all Unicode letters mapped to their
|
||||
// title case, giving priority to the special casing rules.
|
||||
func ToTitleSpecial(_case unicode.SpecialCase, s []byte) []byte {
|
||||
return Map(func(r rune) rune { return _case.ToTitle(r) }, s)
|
||||
}
|
||||
|
||||
// isSeparator reports whether the rune could mark a word boundary.
|
||||
// TODO: update when package unicode captures more of the properties.
|
||||
func isSeparator(r rune) bool {
|
||||
// ASCII alphanumerics and underscore are not separators
|
||||
if r <= 0x7F {
|
||||
switch {
|
||||
case '0' <= r && r <= '9':
|
||||
return false
|
||||
case 'a' <= r && r <= 'z':
|
||||
return false
|
||||
case 'A' <= r && r <= 'Z':
|
||||
return false
|
||||
case r == '_':
|
||||
return false
|
||||
}
|
||||
return true
|
||||
}
|
||||
// Letters and digits are not separators
|
||||
if unicode.IsLetter(r) || unicode.IsDigit(r) {
|
||||
return false
|
||||
}
|
||||
// Otherwise, all we can do for now is treat spaces as separators.
|
||||
return unicode.IsSpace(r)
|
||||
}
|
||||
|
||||
// Title returns a copy of s with all Unicode letters that begin words
|
||||
// mapped to their title case.
|
||||
//
|
||||
// BUG: The rule Title uses for word boundaries does not handle Unicode punctuation properly.
|
||||
func Title(s []byte) []byte {
|
||||
// Use a closure here to remember state.
|
||||
// Hackish but effective. Depends on Map scanning in order and calling
|
||||
// the closure once per rune.
|
||||
prev := ' '
|
||||
return Map(
|
||||
func(r rune) rune {
|
||||
if isSeparator(prev) {
|
||||
prev = r
|
||||
return unicode.ToTitle(r)
|
||||
}
|
||||
prev = r
|
||||
return r
|
||||
},
|
||||
s)
|
||||
}
|
||||
|
||||
// TrimLeftFunc returns a subslice of s by slicing off all leading UTF-8-encoded
|
||||
// Unicode code points c that satisfy f(c).
|
||||
func TrimLeftFunc(s []byte, f func(r rune) bool) []byte {
|
||||
i := indexFunc(s, f, false)
|
||||
if i == -1 {
|
||||
return nil
|
||||
}
|
||||
return s[i:]
|
||||
}
|
||||
|
||||
// TrimRightFunc returns a subslice of s by slicing off all trailing UTF-8
|
||||
// encoded Unicode code points c that satisfy f(c).
|
||||
func TrimRightFunc(s []byte, f func(r rune) bool) []byte {
|
||||
i := lastIndexFunc(s, f, false)
|
||||
if i >= 0 && s[i] >= utf8.RuneSelf {
|
||||
_, wid := utf8.DecodeRune(s[i:])
|
||||
i += wid
|
||||
} else {
|
||||
i++
|
||||
}
|
||||
return s[0:i]
|
||||
}
|
||||
|
||||
// TrimFunc returns a subslice of s by slicing off all leading and trailing
|
||||
// UTF-8-encoded Unicode code points c that satisfy f(c).
|
||||
func TrimFunc(s []byte, f func(r rune) bool) []byte {
|
||||
return TrimRightFunc(TrimLeftFunc(s, f), f)
|
||||
}
|
||||
|
||||
// TrimPrefix returns s without the provided leading prefix string.
|
||||
// If s doesn't start with prefix, s is returned unchanged.
|
||||
func TrimPrefix(s, prefix []byte) []byte {
|
||||
if HasPrefix(s, prefix) {
|
||||
return s[len(prefix):]
|
||||
}
|
||||
return s
|
||||
}
|
||||
|
||||
// TrimSuffix returns s without the provided trailing suffix string.
|
||||
// If s doesn't end with suffix, s is returned unchanged.
|
||||
func TrimSuffix(s, suffix []byte) []byte {
|
||||
if HasSuffix(s, suffix) {
|
||||
return s[:len(s)-len(suffix)]
|
||||
}
|
||||
return s
|
||||
}
|
||||
|
||||
// IndexFunc interprets s as a sequence of UTF-8-encoded Unicode code points.
|
||||
// It returns the byte index in s of the first Unicode
|
||||
// code point satisfying f(c), or -1 if none do.
|
||||
func IndexFunc(s []byte, f func(r rune) bool) int {
|
||||
return indexFunc(s, f, true)
|
||||
}
|
||||
|
||||
// LastIndexFunc interprets s as a sequence of UTF-8-encoded Unicode code points.
|
||||
// It returns the byte index in s of the last Unicode
|
||||
// code point satisfying f(c), or -1 if none do.
|
||||
func LastIndexFunc(s []byte, f func(r rune) bool) int {
|
||||
return lastIndexFunc(s, f, true)
|
||||
}
|
||||
|
||||
// indexFunc is the same as IndexFunc except that if
|
||||
// truth==false, the sense of the predicate function is
|
||||
// inverted.
|
||||
func indexFunc(s []byte, f func(r rune) bool, truth bool) int {
|
||||
start := 0
|
||||
for start < len(s) {
|
||||
wid := 1
|
||||
r := rune(s[start])
|
||||
if r >= utf8.RuneSelf {
|
||||
r, wid = utf8.DecodeRune(s[start:])
|
||||
}
|
||||
if f(r) == truth {
|
||||
return start
|
||||
}
|
||||
start += wid
|
||||
}
|
||||
return -1
|
||||
}
|
||||
|
||||
// lastIndexFunc is the same as LastIndexFunc except that if
|
||||
// truth==false, the sense of the predicate function is
|
||||
// inverted.
|
||||
func lastIndexFunc(s []byte, f func(r rune) bool, truth bool) int {
|
||||
for i := len(s); i > 0; {
|
||||
r, size := rune(s[i-1]), 1
|
||||
if r >= utf8.RuneSelf {
|
||||
r, size = utf8.DecodeLastRune(s[0:i])
|
||||
}
|
||||
i -= size
|
||||
if f(r) == truth {
|
||||
return i
|
||||
}
|
||||
}
|
||||
return -1
|
||||
}
|
||||
|
||||
func makeCutsetFunc(cutset string) func(r rune) bool {
|
||||
return func(r rune) bool {
|
||||
for _, c := range cutset {
|
||||
if c == r {
|
||||
return true
|
||||
}
|
||||
}
|
||||
return false
|
||||
}
|
||||
}
|
||||
|
||||
// Trim returns a subslice of s by slicing off all leading and
|
||||
// trailing UTF-8-encoded Unicode code points contained in cutset.
|
||||
func Trim(s []byte, cutset string) []byte {
|
||||
return TrimFunc(s, makeCutsetFunc(cutset))
|
||||
}
|
||||
|
||||
// TrimLeft returns a subslice of s by slicing off all leading
|
||||
// UTF-8-encoded Unicode code points contained in cutset.
|
||||
func TrimLeft(s []byte, cutset string) []byte {
|
||||
return TrimLeftFunc(s, makeCutsetFunc(cutset))
|
||||
}
|
||||
|
||||
// TrimRight returns a subslice of s by slicing off all trailing
|
||||
// UTF-8-encoded Unicode code points that are contained in cutset.
|
||||
func TrimRight(s []byte, cutset string) []byte {
|
||||
return TrimRightFunc(s, makeCutsetFunc(cutset))
|
||||
}
|
||||
|
||||
// TrimSpace returns a subslice of s by slicing off all leading and
|
||||
// trailing white space, as defined by Unicode.
|
||||
func TrimSpace(s []byte) []byte {
|
||||
return TrimFunc(s, unicode.IsSpace)
|
||||
}
|
||||
|
||||
// Runes returns a slice of runes (Unicode code points) equivalent to s.
|
||||
func Runes(s []byte) []rune {
|
||||
t := make([]rune, utf8.RuneCount(s))
|
||||
i := 0
|
||||
for len(s) > 0 {
|
||||
r, l := utf8.DecodeRune(s)
|
||||
t[i] = r
|
||||
i++
|
||||
s = s[l:]
|
||||
}
|
||||
return t
|
||||
}
|
||||
|
||||
// Replace returns a copy of the slice s with the first n
|
||||
// non-overlapping instances of old replaced by new.
|
||||
// If old is empty, it matches at the beginning of the slice
|
||||
// and after each UTF-8 sequence, yielding up to k+1 replacements
|
||||
// for a k-rune slice.
|
||||
// If n < 0, there is no limit on the number of replacements.
|
||||
func Replace(s, old, new []byte, n int) []byte {
|
||||
m := 0
|
||||
if n != 0 {
|
||||
// Compute number of replacements.
|
||||
m = Count(s, old)
|
||||
}
|
||||
if m == 0 {
|
||||
// Just return a copy.
|
||||
return append([]byte(nil), s...)
|
||||
}
|
||||
if n < 0 || m < n {
|
||||
n = m
|
||||
}
|
||||
|
||||
// Apply replacements to buffer.
|
||||
t := make([]byte, len(s)+n*(len(new)-len(old)))
|
||||
w := 0
|
||||
start := 0
|
||||
for i := 0; i < n; i++ {
|
||||
j := start
|
||||
if len(old) == 0 {
|
||||
if i > 0 {
|
||||
_, wid := utf8.DecodeRune(s[start:])
|
||||
j += wid
|
||||
}
|
||||
} else {
|
||||
j += Index(s[start:], old)
|
||||
}
|
||||
w += copy(t[w:], s[start:j])
|
||||
w += copy(t[w:], new)
|
||||
start = j + len(old)
|
||||
}
|
||||
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 rune
|
||||
if s[0] < utf8.RuneSelf {
|
||||
sr, s = rune(s[0]), s[1:]
|
||||
} else {
|
||||
r, size := utf8.DecodeRune(s)
|
||||
sr, s = r, s[size:]
|
||||
}
|
||||
if t[0] < utf8.RuneSelf {
|
||||
tr, t = rune(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)
|
||||
}
|
||||
Loading…
Add table
Add a link
Reference in a new issue