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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 leveldb
import "github.com/syndtr/goleveldb/leveldb/comparer"
type iComparer struct {
ucmp comparer.Comparer
}
func (icmp *iComparer) uName() string {
return icmp.ucmp.Name()
}
func (icmp *iComparer) uCompare(a, b []byte) int {
return icmp.ucmp.Compare(a, b)
}
func (icmp *iComparer) uSeparator(dst, a, b []byte) []byte {
return icmp.ucmp.Separator(dst, a, b)
}
func (icmp *iComparer) uSuccessor(dst, b []byte) []byte {
return icmp.ucmp.Successor(dst, b)
}
func (icmp *iComparer) Name() string {
return icmp.uName()
}
func (icmp *iComparer) Compare(a, b []byte) int {
x := icmp.ucmp.Compare(iKey(a).ukey(), iKey(b).ukey())
if x == 0 {
if m, n := iKey(a).num(), iKey(b).num(); m > n {
x = -1
} else if m < n {
x = 1
}
}
return x
}
func (icmp *iComparer) Separator(dst, a, b []byte) []byte {
ua, ub := iKey(a).ukey(), iKey(b).ukey()
dst = icmp.ucmp.Separator(dst, ua, ub)
if dst == nil {
return nil
}
if len(dst) < len(ua) && icmp.uCompare(ua, dst) < 0 {
dst = append(dst, kMaxNumBytes...)
} else {
// Did not close possibilities that n maybe longer than len(ub).
dst = append(dst, a[len(a)-8:]...)
}
return dst
}
func (icmp *iComparer) Successor(dst, b []byte) []byte {
ub := iKey(b).ukey()
dst = icmp.ucmp.Successor(dst, ub)
if dst == nil {
return nil
}
if len(dst) < len(ub) && icmp.uCompare(ub, dst) < 0 {
dst = append(dst, kMaxNumBytes...)
} else {
// Did not close possibilities that n maybe longer than len(ub).
dst = append(dst, b[len(b)-8:]...)
}
return dst
}
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