1// Copyright 2013 The Go Authors. All rights reserved. 2// Use of this source code is governed by a BSD-style 3// license that can be found in the LICENSE file. 4 5//go:build !go1.2 6// +build !go1.2 7 8package language 9 10import "sort" 11 12func sortStable(s sort.Interface) { 13 ss := stableSort{ 14 s: s, 15 pos: make([]int, s.Len()), 16 } 17 for i := range ss.pos { 18 ss.pos[i] = i 19 } 20 sort.Sort(&ss) 21} 22 23type stableSort struct { 24 s sort.Interface 25 pos []int 26} 27 28func (s *stableSort) Len() int { 29 return len(s.pos) 30} 31 32func (s *stableSort) Less(i, j int) bool { 33 return s.s.Less(i, j) || !s.s.Less(j, i) && s.pos[i] < s.pos[j] 34} 35 36func (s *stableSort) Swap(i, j int) { 37 s.s.Swap(i, j) 38 s.pos[i], s.pos[j] = s.pos[j], s.pos[i] 39} 40