forked from Shiloh/githaven
71 lines
1.8 KiB
Go
71 lines
1.8 KiB
Go
// Copyright 2017 The Gitea Authors. All rights reserved.
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// SPDX-License-Identifier: MIT
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package base
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import (
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"unicode/utf8"
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"golang.org/x/text/collate"
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"golang.org/x/text/language"
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)
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func naturalSortGetRune(str string, pos int) (r rune, size int, has bool) {
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if pos >= len(str) {
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return 0, 0, false
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}
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r, size = utf8.DecodeRuneInString(str[pos:])
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if r == utf8.RuneError {
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r, size = rune(str[pos]), 1 // if invalid input, treat it as a single byte ascii
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}
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return r, size, true
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}
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func naturalSortAdvance(str string, pos int) (end int, isNumber bool) {
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end = pos
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for {
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r, size, has := naturalSortGetRune(str, end)
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if !has {
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break
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}
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isCurRuneNum := '0' <= r && r <= '9'
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if end == pos {
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isNumber = isCurRuneNum
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end += size
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} else if isCurRuneNum == isNumber {
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end += size
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} else {
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break
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}
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}
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return end, isNumber
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}
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// NaturalSortLess compares two strings so that they could be sorted in natural order
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func NaturalSortLess(s1, s2 string) bool {
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// There is a bug in Golang's collate package: https://github.com/golang/go/issues/67997
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// text/collate: CompareString(collate.Numeric) returns wrong result for "0.0" vs "1.0" #67997
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// So we need to handle the number parts by ourselves
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c := collate.New(language.English, collate.Numeric)
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pos1, pos2 := 0, 0
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for pos1 < len(s1) && pos2 < len(s2) {
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end1, isNum1 := naturalSortAdvance(s1, pos1)
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end2, isNum2 := naturalSortAdvance(s2, pos2)
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part1, part2 := s1[pos1:end1], s2[pos2:end2]
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if isNum1 && isNum2 {
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if part1 != part2 {
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if len(part1) != len(part2) {
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return len(part1) < len(part2)
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}
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return part1 < part2
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}
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} else {
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if cmp := c.CompareString(part1, part2); cmp != 0 {
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return cmp < 0
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}
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}
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pos1, pos2 = end1, end2
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}
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return len(s1) < len(s2)
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}
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