blob: 62f1e75a3c4e70cb62ab0bed89e13644474a30e1 [file] [log] [blame]
// Copyright 2013 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package collate
import (
"bytes"
"sort"
)
const (
maxSortBuffer = 40960
maxSortEntries = 4096
)
type swapper interface {
Swap(i, j int)
}
type sorter struct {
buf *Buffer
keys [][]byte
src swapper
}
func (s *sorter) init(n int) {
if s.buf == nil {
s.buf = &Buffer{}
s.buf.init()
}
if cap(s.keys) < n {
s.keys = make([][]byte, n)
}
s.keys = s.keys[0:n]
}
func (s *sorter) sort(src swapper) {
s.src = src
sort.Sort(s)
}
func (s sorter) Len() int {
return len(s.keys)
}
func (s sorter) Less(i, j int) bool {
return bytes.Compare(s.keys[i], s.keys[j]) == -1
}
func (s sorter) Swap(i, j int) {
s.keys[i], s.keys[j] = s.keys[j], s.keys[i]
s.src.Swap(i, j)
}
// A Lister can be sorted by Collator's Sort method.
type Lister interface {
Len() int
Swap(i, j int)
// Bytes returns the bytes of the text at index i.
Bytes(i int) []byte
}
// Sort uses sort.Sort to sort the strings represented by x using the rules of c.
func (c *Collator) Sort(x Lister) {
n := x.Len()
c.sorter.init(n)
for i := 0; i < n; i++ {
c.sorter.keys[i] = c.Key(c.sorter.buf, x.Bytes(i))
}
c.sorter.sort(x)
}
// SortStrings uses sort.Sort to sort the strings in x using the rules of c.
func (c *Collator) SortStrings(x []string) {
c.sorter.init(len(x))
for i, s := range x {
c.sorter.keys[i] = c.KeyFromString(c.sorter.buf, s)
}
c.sorter.sort(sort.StringSlice(x))
}