// Copyright 2017 The Gitea Authors. All rights reserved.// SPDX-License-Identifier: MIT package base import (	"math/big"	"strings"	"unicode/utf8") // NaturalSortLess compares two strings so that they could be sorted in natural orderfunc NaturalSortLess(s1, s2 string) bool {	s1, s2 = strings.ToLower(s1), strings.ToLower(s2)	var i1, i2 int	for {		rune1, j1, end1 := getNextRune(s1, i1)		rune2, j2, end2 := getNextRune(s2, i2)		if end1 || end2 {			return end1 != end2 && end1		}		dec1 := isDecimal(rune1)		dec2 := isDecimal(rune2)		var less, equal bool		if dec1 && dec2 {			i1, i2, less, equal = compareByNumbers(s1, i1, s2, i2)		} else if !dec1 && !dec2 {			equal = rune1 == rune2			less = rune1 < rune2			i1 = j1			i2 = j2		} else {			return rune1 < rune2		}		if !equal {			return less		}	}} func getNextRune(str string, pos int) (rune, int, bool) {	if pos < len(str) {		r, w := utf8.DecodeRuneInString(str[pos:])		// Fallback to ascii		if r == utf8.RuneError {			r = rune(str[pos])			w = 1		}		return r, pos + w, false	}	return 0, pos, true} func isDecimal(r rune) bool {	return '0' <= r && r <= '9'} func compareByNumbers(str1 string, pos1 int, str2 string, pos2 int) (i1, i2 int, less, equal bool) {	d1, d2 := true, true	var dec1, dec2 string	for d1 || d2 {		if d1 {			r, j, end := getNextRune(str1, pos1)			if !end && isDecimal(r) {				dec1 += string(r)				pos1 = j			} else {				d1 = false			}		}		if d2 {			r, j, end := getNextRune(str2, pos2)			if !end && isDecimal(r) {				dec2 += string(r)				pos2 = j			} else {				d2 = false			}		}	}	less, equal = compareBigNumbers(dec1, dec2)	return pos1, pos2, less, equal} func compareBigNumbers(dec1, dec2 string) (less, equal bool) {	d1, _ := big.NewInt(0).SetString(dec1, 10)	d2, _ := big.NewInt(0).SetString(dec2, 10)	cmp := d1.Cmp(d2)	return cmp < 0, cmp == 0}