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// Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com>
// All rights reserved.
//
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
package comparer
import "bytes"
type bytesComparer struct{}
func (bytesComparer) Compare(a, b []byte) int {
return bytes.Compare(a, b)
}
func (bytesComparer) Name() string {
return "leveldb.BytewiseComparator"
}
func (bytesComparer) Separator(dst, a, b []byte) []byte {
i, n := 0, len(a)
if n > len(b) {
n = len(b)
}
for ; i < n && a[i] == b[i]; i++ {
}
if i >= n {
// Do not shorten if one string is a prefix of the other
} else if c := a[i]; c < 0xff && c+1 < b[i] {
dst = append(dst, a[:i+1]...)
dst[i]++
return dst
}
return nil
}
func (bytesComparer) Successor(dst, b []byte) []byte {
for i, c := range b {
if c != 0xff {
dst = append(dst, b[:i+1]...)
dst[i]++
return dst
}
}
return nil
}
// DefaultComparer are default implementation of the Comparer interface.
// It uses the natural ordering, consistent with bytes.Compare.
var DefaultComparer = bytesComparer{}
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