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stringutil.go
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stringutil.go
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// Copyright (c) 2012-2016 The go-diff authors. All rights reserved.
// https://github.com/sergi/go-diff
// See the included LICENSE file for license details.
//
// go-diff is a Go implementation of Google's Diff, Match, and Patch library
// Original library is Copyright (c) 2006 Google Inc.
// http://code.google.com/p/google-diff-match-patch/
package diffmatchpatch
import (
"strings"
"unicode/utf8"
)
// unescaper unescapes selected chars for compatibility with JavaScript's encodeURI.
// In speed critical applications this could be dropped since the receiving application will certainly decode these fine. Note that this function is case-sensitive. Thus "%3F" would not be unescaped. But this is ok because it is only called with the output of HttpUtility.UrlEncode which returns lowercase hex. Example: "%3f" -> "?", "%24" -> "$", etc.
var unescaper = strings.NewReplacer(
"%21", "!", "%7E", "~", "%27", "'",
"%28", "(", "%29", ")", "%3B", ";",
"%2F", "/", "%3F", "?", "%3A", ":",
"%40", "@", "%26", "&", "%3D", "=",
"%2B", "+", "%24", "$", "%2C", ",", "%23", "#", "%2A", "*")
// indexOf returns the first index of pattern in str, starting at str[i].
func indexOf(str string, pattern string, i int) int {
if i > len(str)-1 {
return -1
}
if i <= 0 {
return strings.Index(str, pattern)
}
ind := strings.Index(str[i:], pattern)
if ind == -1 {
return -1
}
return ind + i
}
// lastIndexOf returns the last index of pattern in str, starting at str[i].
func lastIndexOf(str string, pattern string, i int) int {
if i < 0 {
return -1
}
if i >= len(str) {
return strings.LastIndex(str, pattern)
}
_, size := utf8.DecodeRuneInString(str[i:])
return strings.LastIndex(str[:i+size], pattern)
}
// runesIndexOf returns the index of pattern in target, starting at target[i].
func runesIndexOf(target, pattern []rune, i int) int {
if i > len(target)-1 {
return -1
}
if i <= 0 {
return runesIndex(target, pattern)
}
ind := runesIndex(target[i:], pattern)
if ind == -1 {
return -1
}
return ind + i
}
func runesEqual(r1, r2 []rune) bool {
if len(r1) != len(r2) {
return false
}
for i, c := range r1 {
if c != r2[i] {
return false
}
}
return true
}
// runesIndex is the equivalent of strings.Index for rune slices.
func runesIndex(r1, r2 []rune) int {
last := len(r1) - len(r2)
for i := 0; i <= last; i++ {
if runesEqual(r1[i:i+len(r2)], r2) {
return i
}
}
return -1
}