snapshot of https://github.com/go-gitea/gitea.git (main, 2026-09-15; blobs > 131072B omitted)

modules/base/natural_sort.go

@@ -0,0 +1,84 @@
+// Copyright 2017 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package base
+
+import (
+	"strings"
+	"unicode/utf8"
+
+	"golang.org/x/text/collate"
+	"golang.org/x/text/language"
+)
+
+func naturalSortGetRune(str string, pos int) (r rune, size int, has bool) {
+	if pos >= len(str) {
+		return 0, 0, false
+	}
+	r, size = utf8.DecodeRuneInString(str[pos:])
+	if r == utf8.RuneError {
+		r, size = rune(str[pos]), 1 // if invalid input, treat it as a single byte ascii
+	}
+	return r, size, true
+}
+
+func naturalSortAdvance(str string, pos int) (end int, isNumber bool) {
+	end = pos
+	for {
+		r, size, has := naturalSortGetRune(str, end)
+		if !has {
+			break
+		}
+		isCurRuneNum := '0' <= r && r <= '9'
+		if end == pos {
+			isNumber = isCurRuneNum
+			end += size
+		} else if isCurRuneNum == isNumber {
+			end += size
+		} else {
+			break
+		}
+	}
+	return end, isNumber
+}
+
+// naturalSortTrimZeros strips leading '0's, keeping one character so "000" collapses to "0"
+func naturalSortTrimZeros(num string) string {
+	i := 0
+	for i < len(num)-1 && num[i] == '0' {
+		i++
+	}
+	return num[i:]
+}
+
+// NaturalSortCompare compares two strings so that they could be sorted in natural order
+func NaturalSortCompare(s1, s2 string) int {
+	// There is a bug in Golang's collate package: https://github.com/golang/go/issues/67997
+	// text/collate: CompareString(collate.Numeric) returns wrong result for "0.0" vs "1.0" #67997
+	// So we need to handle the number parts by ourselves
+	c := collate.New(language.English, collate.Numeric)
+	pos1, pos2 := 0, 0
+	for pos1 < len(s1) && pos2 < len(s2) {
+		end1, isNum1 := naturalSortAdvance(s1, pos1)
+		end2, isNum2 := naturalSortAdvance(s2, pos2)
+		part1, part2 := s1[pos1:end1], s2[pos2:end2]
+		if isNum1 && isNum2 {
+			if part1 != part2 {
+				num1, num2 := naturalSortTrimZeros(part1), naturalSortTrimZeros(part2)
+				if len(num1) != len(num2) {
+					return len(num1) - len(num2) // without leading zeros, more digits means larger value
+				}
+				if cmp := strings.Compare(num1, num2); cmp != 0 {
+					return cmp // equal digit count, so byte order is numeric order
+				}
+				return len(part1) - len(part2) // equal value, fewer leading zeros sorts first
+			}
+		} else {
+			if cmp := c.CompareString(part1, part2); cmp != 0 {
+				return cmp
+			}
+		}
+		pos1, pos2 = end1, end2
+	}
+	return len(s1) - len(s2)
+}