23645fe05f
* Sort repository tree entries in natural way * Fix sort for different length strings with first parts equal * Improve test case * Refactor return statements * Update gitea/git dependency
90 lines
1.9 KiB
Go
90 lines
1.9 KiB
Go
// Copyright 2017 The Gitea Authors. All rights reserved.
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// Use of this source code is governed by a MIT-style
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// license that can be found in the LICENSE file.
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package base
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import (
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"math/big"
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"unicode/utf8"
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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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var i1, i2 int
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for {
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rune1, j1, end1 := getNextRune(s1, i1)
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rune2, j2, end2 := getNextRune(s2, i2)
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if end1 || end2 {
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return end1 != end2 && end1
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}
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dec1 := isDecimal(rune1)
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dec2 := isDecimal(rune2)
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var less, equal bool
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if dec1 && dec2 {
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i1, i2, less, equal = compareByNumbers(s1, i1, s2, i2)
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} else if !dec1 && !dec2 {
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equal = rune1 == rune2
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less = rune1 < rune2
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i1 = j1
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i2 = j2
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} else {
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return rune1 < rune2
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}
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if !equal {
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return less
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}
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}
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}
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func getNextRune(str string, pos int) (rune, int, bool) {
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if pos < len(str) {
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r, w := utf8.DecodeRuneInString(str[pos:])
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// Fallback to ascii
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if r == utf8.RuneError {
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r = rune(str[pos])
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w = 1
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}
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return r, pos + w, false
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}
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return 0, pos, true
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}
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func isDecimal(r rune) bool {
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return '0' <= r && r <= '9'
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}
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func compareByNumbers(str1 string, pos1 int, str2 string, pos2 int) (i1, i2 int, less, equal bool) {
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var d1, d2 bool = true, true
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var dec1, dec2 string
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for d1 || d2 {
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if d1 {
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r, j, end := getNextRune(str1, pos1)
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if !end && isDecimal(r) {
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dec1 += string(r)
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pos1 = j
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} else {
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d1 = false
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}
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}
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if d2 {
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r, j, end := getNextRune(str2, pos2)
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if !end && isDecimal(r) {
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dec2 += string(r)
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pos2 = j
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} else {
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d2 = false
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}
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}
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}
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less, equal = compareBigNumbers(dec1, dec2)
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return pos1, pos2, less, equal
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}
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func compareBigNumbers(dec1, dec2 string) (less, equal bool) {
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d1, _ := big.NewInt(0).SetString(dec1, 10)
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d2, _ := big.NewInt(0).SetString(dec2, 10)
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cmp := d1.Cmp(d2)
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return cmp < 0, cmp == 0
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}
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