mirror of
https://github.com/go-gitea/gitea.git
synced 2024-12-04 14:46:57 -05:00
548 lines
12 KiB
Go
548 lines
12 KiB
Go
|
// Copyright 2015 Huan Du. All rights reserved.
|
||
|
// Licensed under the MIT license that can be found in the LICENSE file.
|
||
|
|
||
|
package xstrings
|
||
|
|
||
|
import (
|
||
|
"bytes"
|
||
|
"unicode"
|
||
|
"unicode/utf8"
|
||
|
)
|
||
|
|
||
|
type runeRangeMap struct {
|
||
|
FromLo rune // Lower bound of range map.
|
||
|
FromHi rune // An inclusive higher bound of range map.
|
||
|
ToLo rune
|
||
|
ToHi rune
|
||
|
}
|
||
|
|
||
|
type runeDict struct {
|
||
|
Dict [unicode.MaxASCII + 1]rune
|
||
|
}
|
||
|
|
||
|
type runeMap map[rune]rune
|
||
|
|
||
|
// Translator can translate string with pre-compiled from and to patterns.
|
||
|
// If a from/to pattern pair needs to be used more than once, it's recommended
|
||
|
// to create a Translator and reuse it.
|
||
|
type Translator struct {
|
||
|
quickDict *runeDict // A quick dictionary to look up rune by index. Only available for latin runes.
|
||
|
runeMap runeMap // Rune map for translation.
|
||
|
ranges []*runeRangeMap // Ranges of runes.
|
||
|
mappedRune rune // If mappedRune >= 0, all matched runes are translated to the mappedRune.
|
||
|
reverted bool // If to pattern is empty, all matched characters will be deleted.
|
||
|
hasPattern bool
|
||
|
}
|
||
|
|
||
|
// NewTranslator creates new Translator through a from/to pattern pair.
|
||
|
func NewTranslator(from, to string) *Translator {
|
||
|
tr := &Translator{}
|
||
|
|
||
|
if from == "" {
|
||
|
return tr
|
||
|
}
|
||
|
|
||
|
reverted := from[0] == '^'
|
||
|
deletion := len(to) == 0
|
||
|
|
||
|
if reverted {
|
||
|
from = from[1:]
|
||
|
}
|
||
|
|
||
|
var fromStart, fromEnd, fromRangeStep rune
|
||
|
var toStart, toEnd, toRangeStep rune
|
||
|
var fromRangeSize, toRangeSize rune
|
||
|
var singleRunes []rune
|
||
|
|
||
|
// Update the to rune range.
|
||
|
updateRange := func() {
|
||
|
// No more rune to read in the to rune pattern.
|
||
|
if toEnd == utf8.RuneError {
|
||
|
return
|
||
|
}
|
||
|
|
||
|
if toRangeStep == 0 {
|
||
|
to, toStart, toEnd, toRangeStep = nextRuneRange(to, toEnd)
|
||
|
return
|
||
|
}
|
||
|
|
||
|
// Current range is not empty. Consume 1 rune from start.
|
||
|
if toStart != toEnd {
|
||
|
toStart += toRangeStep
|
||
|
return
|
||
|
}
|
||
|
|
||
|
// No more rune. Repeat the last rune.
|
||
|
if to == "" {
|
||
|
toEnd = utf8.RuneError
|
||
|
return
|
||
|
}
|
||
|
|
||
|
// Both start and end are used. Read two more runes from the to pattern.
|
||
|
to, toStart, toEnd, toRangeStep = nextRuneRange(to, utf8.RuneError)
|
||
|
}
|
||
|
|
||
|
if deletion {
|
||
|
toStart = utf8.RuneError
|
||
|
toEnd = utf8.RuneError
|
||
|
} else {
|
||
|
// If from pattern is reverted, only the last rune in the to pattern will be used.
|
||
|
if reverted {
|
||
|
var size int
|
||
|
|
||
|
for len(to) > 0 {
|
||
|
toStart, size = utf8.DecodeRuneInString(to)
|
||
|
to = to[size:]
|
||
|
}
|
||
|
|
||
|
toEnd = utf8.RuneError
|
||
|
} else {
|
||
|
to, toStart, toEnd, toRangeStep = nextRuneRange(to, utf8.RuneError)
|
||
|
}
|
||
|
}
|
||
|
|
||
|
fromEnd = utf8.RuneError
|
||
|
|
||
|
for len(from) > 0 {
|
||
|
from, fromStart, fromEnd, fromRangeStep = nextRuneRange(from, fromEnd)
|
||
|
|
||
|
// fromStart is a single character. Just map it with a rune in the to pattern.
|
||
|
if fromRangeStep == 0 {
|
||
|
singleRunes = tr.addRune(fromStart, toStart, singleRunes)
|
||
|
updateRange()
|
||
|
continue
|
||
|
}
|
||
|
|
||
|
for toEnd != utf8.RuneError && fromStart != fromEnd {
|
||
|
// If mapped rune is a single character instead of a range, simply shift first
|
||
|
// rune in the range.
|
||
|
if toRangeStep == 0 {
|
||
|
singleRunes = tr.addRune(fromStart, toStart, singleRunes)
|
||
|
updateRange()
|
||
|
fromStart += fromRangeStep
|
||
|
continue
|
||
|
}
|
||
|
|
||
|
fromRangeSize = (fromEnd - fromStart) * fromRangeStep
|
||
|
toRangeSize = (toEnd - toStart) * toRangeStep
|
||
|
|
||
|
// Not enough runes in the to pattern. Need to read more.
|
||
|
if fromRangeSize > toRangeSize {
|
||
|
fromStart, toStart = tr.addRuneRange(fromStart, fromStart+toRangeSize*fromRangeStep, toStart, toEnd, singleRunes)
|
||
|
fromStart += fromRangeStep
|
||
|
updateRange()
|
||
|
|
||
|
// Edge case: If fromRangeSize == toRangeSize + 1, the last fromStart value needs be considered
|
||
|
// as a single rune.
|
||
|
if fromStart == fromEnd {
|
||
|
singleRunes = tr.addRune(fromStart, toStart, singleRunes)
|
||
|
updateRange()
|
||
|
}
|
||
|
|
||
|
continue
|
||
|
}
|
||
|
|
||
|
fromStart, toStart = tr.addRuneRange(fromStart, fromEnd, toStart, toStart+fromRangeSize*toRangeStep, singleRunes)
|
||
|
updateRange()
|
||
|
break
|
||
|
}
|
||
|
|
||
|
if fromStart == fromEnd {
|
||
|
fromEnd = utf8.RuneError
|
||
|
continue
|
||
|
}
|
||
|
|
||
|
fromStart, toStart = tr.addRuneRange(fromStart, fromEnd, toStart, toStart, singleRunes)
|
||
|
fromEnd = utf8.RuneError
|
||
|
}
|
||
|
|
||
|
if fromEnd != utf8.RuneError {
|
||
|
singleRunes = tr.addRune(fromEnd, toStart, singleRunes)
|
||
|
}
|
||
|
|
||
|
tr.reverted = reverted
|
||
|
tr.mappedRune = -1
|
||
|
tr.hasPattern = true
|
||
|
|
||
|
// Translate RuneError only if in deletion or reverted mode.
|
||
|
if deletion || reverted {
|
||
|
tr.mappedRune = toStart
|
||
|
}
|
||
|
|
||
|
return tr
|
||
|
}
|
||
|
|
||
|
func (tr *Translator) addRune(from, to rune, singleRunes []rune) []rune {
|
||
|
if from <= unicode.MaxASCII {
|
||
|
if tr.quickDict == nil {
|
||
|
tr.quickDict = &runeDict{}
|
||
|
}
|
||
|
|
||
|
tr.quickDict.Dict[from] = to
|
||
|
} else {
|
||
|
if tr.runeMap == nil {
|
||
|
tr.runeMap = make(runeMap)
|
||
|
}
|
||
|
|
||
|
tr.runeMap[from] = to
|
||
|
}
|
||
|
|
||
|
singleRunes = append(singleRunes, from)
|
||
|
return singleRunes
|
||
|
}
|
||
|
|
||
|
func (tr *Translator) addRuneRange(fromLo, fromHi, toLo, toHi rune, singleRunes []rune) (rune, rune) {
|
||
|
var r rune
|
||
|
var rrm *runeRangeMap
|
||
|
|
||
|
if fromLo < fromHi {
|
||
|
rrm = &runeRangeMap{
|
||
|
FromLo: fromLo,
|
||
|
FromHi: fromHi,
|
||
|
ToLo: toLo,
|
||
|
ToHi: toHi,
|
||
|
}
|
||
|
} else {
|
||
|
rrm = &runeRangeMap{
|
||
|
FromLo: fromHi,
|
||
|
FromHi: fromLo,
|
||
|
ToLo: toHi,
|
||
|
ToHi: toLo,
|
||
|
}
|
||
|
}
|
||
|
|
||
|
// If there is any single rune conflicts with this rune range, clear single rune record.
|
||
|
for _, r = range singleRunes {
|
||
|
if rrm.FromLo <= r && r <= rrm.FromHi {
|
||
|
if r <= unicode.MaxASCII {
|
||
|
tr.quickDict.Dict[r] = 0
|
||
|
} else {
|
||
|
delete(tr.runeMap, r)
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
|
||
|
tr.ranges = append(tr.ranges, rrm)
|
||
|
return fromHi, toHi
|
||
|
}
|
||
|
|
||
|
func nextRuneRange(str string, last rune) (remaining string, start, end rune, rangeStep rune) {
|
||
|
var r rune
|
||
|
var size int
|
||
|
|
||
|
remaining = str
|
||
|
escaping := false
|
||
|
isRange := false
|
||
|
|
||
|
for len(remaining) > 0 {
|
||
|
r, size = utf8.DecodeRuneInString(remaining)
|
||
|
remaining = remaining[size:]
|
||
|
|
||
|
// Parse special characters.
|
||
|
if !escaping {
|
||
|
if r == '\\' {
|
||
|
escaping = true
|
||
|
continue
|
||
|
}
|
||
|
|
||
|
if r == '-' {
|
||
|
// Ignore slash at beginning of string.
|
||
|
if last == utf8.RuneError {
|
||
|
continue
|
||
|
}
|
||
|
|
||
|
start = last
|
||
|
isRange = true
|
||
|
continue
|
||
|
}
|
||
|
}
|
||
|
|
||
|
escaping = false
|
||
|
|
||
|
if last != utf8.RuneError {
|
||
|
// This is a range which start and end are the same.
|
||
|
// Considier it as a normal character.
|
||
|
if isRange && last == r {
|
||
|
isRange = false
|
||
|
continue
|
||
|
}
|
||
|
|
||
|
start = last
|
||
|
end = r
|
||
|
|
||
|
if isRange {
|
||
|
if start < end {
|
||
|
rangeStep = 1
|
||
|
} else {
|
||
|
rangeStep = -1
|
||
|
}
|
||
|
}
|
||
|
|
||
|
return
|
||
|
}
|
||
|
|
||
|
last = r
|
||
|
}
|
||
|
|
||
|
start = last
|
||
|
end = utf8.RuneError
|
||
|
return
|
||
|
}
|
||
|
|
||
|
// Translate str with a from/to pattern pair.
|
||
|
//
|
||
|
// See comment in Translate function for usage and samples.
|
||
|
func (tr *Translator) Translate(str string) string {
|
||
|
if !tr.hasPattern || str == "" {
|
||
|
return str
|
||
|
}
|
||
|
|
||
|
var r rune
|
||
|
var size int
|
||
|
var needTr bool
|
||
|
|
||
|
orig := str
|
||
|
|
||
|
var output *bytes.Buffer
|
||
|
|
||
|
for len(str) > 0 {
|
||
|
r, size = utf8.DecodeRuneInString(str)
|
||
|
r, needTr = tr.TranslateRune(r)
|
||
|
|
||
|
if needTr && output == nil {
|
||
|
output = allocBuffer(orig, str)
|
||
|
}
|
||
|
|
||
|
if r != utf8.RuneError && output != nil {
|
||
|
output.WriteRune(r)
|
||
|
}
|
||
|
|
||
|
str = str[size:]
|
||
|
}
|
||
|
|
||
|
// No character is translated.
|
||
|
if output == nil {
|
||
|
return orig
|
||
|
}
|
||
|
|
||
|
return output.String()
|
||
|
}
|
||
|
|
||
|
// TranslateRune return translated rune and true if r matches the from pattern.
|
||
|
// If r doesn't match the pattern, original r is returned and translated is false.
|
||
|
func (tr *Translator) TranslateRune(r rune) (result rune, translated bool) {
|
||
|
switch {
|
||
|
case tr.quickDict != nil:
|
||
|
if r <= unicode.MaxASCII {
|
||
|
result = tr.quickDict.Dict[r]
|
||
|
|
||
|
if result != 0 {
|
||
|
translated = true
|
||
|
|
||
|
if tr.mappedRune >= 0 {
|
||
|
result = tr.mappedRune
|
||
|
}
|
||
|
|
||
|
break
|
||
|
}
|
||
|
}
|
||
|
|
||
|
fallthrough
|
||
|
|
||
|
case tr.runeMap != nil:
|
||
|
var ok bool
|
||
|
|
||
|
if result, ok = tr.runeMap[r]; ok {
|
||
|
translated = true
|
||
|
|
||
|
if tr.mappedRune >= 0 {
|
||
|
result = tr.mappedRune
|
||
|
}
|
||
|
|
||
|
break
|
||
|
}
|
||
|
|
||
|
fallthrough
|
||
|
|
||
|
default:
|
||
|
var rrm *runeRangeMap
|
||
|
ranges := tr.ranges
|
||
|
|
||
|
for i := len(ranges) - 1; i >= 0; i-- {
|
||
|
rrm = ranges[i]
|
||
|
|
||
|
if rrm.FromLo <= r && r <= rrm.FromHi {
|
||
|
translated = true
|
||
|
|
||
|
if tr.mappedRune >= 0 {
|
||
|
result = tr.mappedRune
|
||
|
break
|
||
|
}
|
||
|
|
||
|
if rrm.ToLo < rrm.ToHi {
|
||
|
result = rrm.ToLo + r - rrm.FromLo
|
||
|
} else if rrm.ToLo > rrm.ToHi {
|
||
|
// ToHi can be smaller than ToLo if range is from higher to lower.
|
||
|
result = rrm.ToLo - r + rrm.FromLo
|
||
|
} else {
|
||
|
result = rrm.ToLo
|
||
|
}
|
||
|
|
||
|
break
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
|
||
|
if tr.reverted {
|
||
|
if !translated {
|
||
|
result = tr.mappedRune
|
||
|
}
|
||
|
|
||
|
translated = !translated
|
||
|
}
|
||
|
|
||
|
if !translated {
|
||
|
result = r
|
||
|
}
|
||
|
|
||
|
return
|
||
|
}
|
||
|
|
||
|
// HasPattern returns true if Translator has one pattern at least.
|
||
|
func (tr *Translator) HasPattern() bool {
|
||
|
return tr.hasPattern
|
||
|
}
|
||
|
|
||
|
// Translate str with the characters defined in from replaced by characters defined in to.
|
||
|
//
|
||
|
// From and to are patterns representing a set of characters. Pattern is defined as following.
|
||
|
//
|
||
|
// * Special characters
|
||
|
// * '-' means a range of runes, e.g.
|
||
|
// * "a-z" means all characters from 'a' to 'z' inclusive;
|
||
|
// * "z-a" means all characters from 'z' to 'a' inclusive.
|
||
|
// * '^' as first character means a set of all runes excepted listed, e.g.
|
||
|
// * "^a-z" means all characters except 'a' to 'z' inclusive.
|
||
|
// * '\' escapes special characters.
|
||
|
// * Normal character represents itself, e.g. "abc" is a set including 'a', 'b' and 'c'.
|
||
|
//
|
||
|
// Translate will try to find a 1:1 mapping from from to to.
|
||
|
// If to is smaller than from, last rune in to will be used to map "out of range" characters in from.
|
||
|
//
|
||
|
// Note that '^' only works in the from pattern. It will be considered as a normal character in the to pattern.
|
||
|
//
|
||
|
// If the to pattern is an empty string, Translate works exactly the same as Delete.
|
||
|
//
|
||
|
// Samples:
|
||
|
// Translate("hello", "aeiou", "12345") => "h2ll4"
|
||
|
// Translate("hello", "a-z", "A-Z") => "HELLO"
|
||
|
// Translate("hello", "z-a", "a-z") => "svool"
|
||
|
// Translate("hello", "aeiou", "*") => "h*ll*"
|
||
|
// Translate("hello", "^l", "*") => "**ll*"
|
||
|
// Translate("hello ^ world", `\^lo`, "*") => "he*** * w*r*d"
|
||
|
func Translate(str, from, to string) string {
|
||
|
tr := NewTranslator(from, to)
|
||
|
return tr.Translate(str)
|
||
|
}
|
||
|
|
||
|
// Delete runes in str matching the pattern.
|
||
|
// Pattern is defined in Translate function.
|
||
|
//
|
||
|
// Samples:
|
||
|
// Delete("hello", "aeiou") => "hll"
|
||
|
// Delete("hello", "a-k") => "llo"
|
||
|
// Delete("hello", "^a-k") => "he"
|
||
|
func Delete(str, pattern string) string {
|
||
|
tr := NewTranslator(pattern, "")
|
||
|
return tr.Translate(str)
|
||
|
}
|
||
|
|
||
|
// Count how many runes in str match the pattern.
|
||
|
// Pattern is defined in Translate function.
|
||
|
//
|
||
|
// Samples:
|
||
|
// Count("hello", "aeiou") => 3
|
||
|
// Count("hello", "a-k") => 3
|
||
|
// Count("hello", "^a-k") => 2
|
||
|
func Count(str, pattern string) int {
|
||
|
if pattern == "" || str == "" {
|
||
|
return 0
|
||
|
}
|
||
|
|
||
|
var r rune
|
||
|
var size int
|
||
|
var matched bool
|
||
|
|
||
|
tr := NewTranslator(pattern, "")
|
||
|
cnt := 0
|
||
|
|
||
|
for len(str) > 0 {
|
||
|
r, size = utf8.DecodeRuneInString(str)
|
||
|
str = str[size:]
|
||
|
|
||
|
if _, matched = tr.TranslateRune(r); matched {
|
||
|
cnt++
|
||
|
}
|
||
|
}
|
||
|
|
||
|
return cnt
|
||
|
}
|
||
|
|
||
|
// Squeeze deletes adjacent repeated runes in str.
|
||
|
// If pattern is not empty, only runes matching the pattern will be squeezed.
|
||
|
//
|
||
|
// Samples:
|
||
|
// Squeeze("hello", "") => "helo"
|
||
|
// Squeeze("hello", "m-z") => "hello"
|
||
|
// Squeeze("hello world", " ") => "hello world"
|
||
|
func Squeeze(str, pattern string) string {
|
||
|
var last, r rune
|
||
|
var size int
|
||
|
var skipSqueeze, matched bool
|
||
|
var tr *Translator
|
||
|
var output *bytes.Buffer
|
||
|
|
||
|
orig := str
|
||
|
last = -1
|
||
|
|
||
|
if len(pattern) > 0 {
|
||
|
tr = NewTranslator(pattern, "")
|
||
|
}
|
||
|
|
||
|
for len(str) > 0 {
|
||
|
r, size = utf8.DecodeRuneInString(str)
|
||
|
|
||
|
// Need to squeeze the str.
|
||
|
if last == r && !skipSqueeze {
|
||
|
if tr != nil {
|
||
|
if _, matched = tr.TranslateRune(r); !matched {
|
||
|
skipSqueeze = true
|
||
|
}
|
||
|
}
|
||
|
|
||
|
if output == nil {
|
||
|
output = allocBuffer(orig, str)
|
||
|
}
|
||
|
|
||
|
if skipSqueeze {
|
||
|
output.WriteRune(r)
|
||
|
}
|
||
|
} else {
|
||
|
if output != nil {
|
||
|
output.WriteRune(r)
|
||
|
}
|
||
|
|
||
|
last = r
|
||
|
skipSqueeze = false
|
||
|
}
|
||
|
|
||
|
str = str[size:]
|
||
|
}
|
||
|
|
||
|
if output == nil {
|
||
|
return orig
|
||
|
}
|
||
|
|
||
|
return output.String()
|
||
|
}
|