76 lines
1.7 KiB
Go
76 lines
1.7 KiB
Go
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// Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com>
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// All rights reserved.
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//
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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package leveldb
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import "github.com/syndtr/goleveldb/leveldb/comparer"
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type iComparer struct {
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ucmp comparer.Comparer
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}
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func (icmp *iComparer) uName() string {
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return icmp.ucmp.Name()
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}
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func (icmp *iComparer) uCompare(a, b []byte) int {
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return icmp.ucmp.Compare(a, b)
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}
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func (icmp *iComparer) uSeparator(dst, a, b []byte) []byte {
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return icmp.ucmp.Separator(dst, a, b)
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}
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func (icmp *iComparer) uSuccessor(dst, b []byte) []byte {
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return icmp.ucmp.Successor(dst, b)
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}
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func (icmp *iComparer) Name() string {
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return icmp.uName()
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}
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func (icmp *iComparer) Compare(a, b []byte) int {
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x := icmp.ucmp.Compare(internalKey(a).ukey(), internalKey(b).ukey())
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if x == 0 {
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if m, n := internalKey(a).num(), internalKey(b).num(); m > n {
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x = -1
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} else if m < n {
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x = 1
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}
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}
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return x
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}
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func (icmp *iComparer) Separator(dst, a, b []byte) []byte {
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ua, ub := internalKey(a).ukey(), internalKey(b).ukey()
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dst = icmp.ucmp.Separator(dst, ua, ub)
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if dst == nil {
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return nil
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}
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if len(dst) < len(ua) && icmp.uCompare(ua, dst) < 0 {
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dst = append(dst, keyMaxNumBytes...)
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} else {
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// Did not close possibilities that n maybe longer than len(ub).
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dst = append(dst, a[len(a)-8:]...)
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}
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return dst
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}
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func (icmp *iComparer) Successor(dst, b []byte) []byte {
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ub := internalKey(b).ukey()
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dst = icmp.ucmp.Successor(dst, ub)
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if dst == nil {
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return nil
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}
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if len(dst) < len(ub) && icmp.uCompare(ub, dst) < 0 {
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dst = append(dst, keyMaxNumBytes...)
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} else {
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// Did not close possibilities that n maybe longer than len(ub).
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dst = append(dst, b[len(b)-8:]...)
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}
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return dst
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}
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