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Java > Open Source Codes > com > caucho > db > index > LongKeyCompare


1 /*
2  * Copyright (c) 1998-2006 Caucho Technology -- all rights reserved
3  *
4  * This file is part of Resin(R) Open Source
5  *
6  * Each copy or derived work must preserve the copyright notice and this
7  * notice unmodified.
8  *
9  * Resin Open Source is free software; you can redistribute it and/or modify
10  * it under the terms of the GNU General Public License as published by
11  * the Free Software Foundation; either version 2 of the License, or
12  * (at your option) any later version.
13  *
14  * Resin Open Source is distributed in the hope that it will be useful,
15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE, or any warranty
17  * of NON-INFRINGEMENT. See the GNU General Public License for more
18  * details.
19  *
20  * You should have received a copy of the GNU General Public License
21  * along with Resin Open Source; if not, write to the
22  * Free SoftwareFoundation, Inc.
23  * 59 Temple Place, Suite 330
24  * Boston, MA 02111-1307 USA
25  *
26  * @author Scott Ferguson
27  */
28
29 package com.caucho.db.index;
30
31 /**
32  * Compares two long keys.
33  */
34 public class LongKeyCompare extends KeyCompare {
35   /**
36    * Compares the key to the block data.
37    */
38   public int compare(byte []keyBuffer, int keyOffset,
39              byte []block, int offset, int length)
40   {
41     long key = (((keyBuffer[keyOffset + 0] & 0xffL) << 56) +
42         ((keyBuffer[keyOffset + 1] & 0xffL) << 48) +
43         ((keyBuffer[keyOffset + 2] & 0xffL) << 40) +
44         ((keyBuffer[keyOffset + 3] & 0xffL) << 32) +
45         
46         ((keyBuffer[keyOffset + 4] & 0xffL) << 24) +
47         ((keyBuffer[keyOffset + 5] & 0xffL) << 16) +
48         ((keyBuffer[keyOffset + 6] & 0xffL) << 8) +
49         ((keyBuffer[keyOffset + 7] & 0xffL) << 0));
50     
51     long value = (((block[offset + 0] & 0xffL) << 56) +
52           ((block[offset + 1] & 0xffL) << 48) +
53           ((block[offset + 2] & 0xffL) << 40) +
54           ((block[offset + 3] & 0xffL) << 32) +
55          
56           ((block[offset + 4] & 0xffL) << 24) +
57           ((block[offset + 5] & 0xffL) << 16) +
58           ((block[offset + 6] & 0xffL) << 8) +
59           ((block[offset + 7] & 0xffL) << 0));
60
61     if (key == value)
62       return 0;
63     else if (key < value)
64       return -1;
65     else
66       return 1;
67   }
68 }
69
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