Scott Baker | 2d89798 | 2019-09-24 11:50:08 -0700 | [diff] [blame^] | 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 | // +build !go1.2 |
| 6 | |
| 7 | package language |
| 8 | |
| 9 | import "sort" |
| 10 | |
| 11 | func sortStable(s sort.Interface) { |
| 12 | ss := stableSort{ |
| 13 | s: s, |
| 14 | pos: make([]int, s.Len()), |
| 15 | } |
| 16 | for i := range ss.pos { |
| 17 | ss.pos[i] = i |
| 18 | } |
| 19 | sort.Sort(&ss) |
| 20 | } |
| 21 | |
| 22 | type stableSort struct { |
| 23 | s sort.Interface |
| 24 | pos []int |
| 25 | } |
| 26 | |
| 27 | func (s *stableSort) Len() int { |
| 28 | return len(s.pos) |
| 29 | } |
| 30 | |
| 31 | func (s *stableSort) Less(i, j int) bool { |
| 32 | return s.s.Less(i, j) || !s.s.Less(j, i) && s.pos[i] < s.pos[j] |
| 33 | } |
| 34 | |
| 35 | func (s *stableSort) Swap(i, j int) { |
| 36 | s.s.Swap(i, j) |
| 37 | s.pos[i], s.pos[j] = s.pos[j], s.pos[i] |
| 38 | } |