01: /*
02: * Copyright (c) 1998-2008 Caucho Technology -- all rights reserved
03: *
04: * This file is part of Resin(R) Open Source
05: *
06: * Each copy or derived work must preserve the copyright notice and this
07: * notice unmodified.
08: *
09: * 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: *
23: * Free Software Foundation, Inc.
24: * 59 Temple Place, Suite 330
25: * Boston, MA 02111-1307 USA
26: *
27: * @author Scott Ferguson
28: */
29:
30: package com.caucho.db.index;
31:
32: /**
33: * Compares two keys.
34: */
35: public class StringKeyCompare extends KeyCompare {
36: /**
37: * Compares the key to the block data.
38: */
39: public int compare(byte[] keyBuffer, int keyOffset, byte[] block,
40: int offset, int length) {
41: int keyLen = keyBuffer[keyOffset] & 0xff;
42: int blockLen = block[offset] & 0xff;
43:
44: int keySize = 2 * keyLen;
45: int blockSize = 2 * blockLen;
46:
47: int end = keySize;
48: if (blockSize < end)
49: end = blockSize;
50:
51: for (int i = 1; i <= end; i++) {
52: int ch1 = keyBuffer[keyOffset + i] & 0xff;
53: int ch2 = block[offset + i] & 0xff;
54:
55: if (ch1 < ch2)
56: return -1;
57: else if (ch2 < ch1)
58: return 1;
59: }
60:
61: if (keyLen == blockLen)
62: return 0;
63:
64: if (keyLen < blockLen)
65: return -1;
66: else if (blockLen < keyLen)
67: return 1;
68: else
69: return 0;
70: }
71:
72: public String toString(byte[] buffer, int offset, int length) {
73: StringBuilder sb = new StringBuilder();
74:
75: int keyLen = buffer[offset];
76:
77: for (int j = 0; j < keyLen; j++) {
78: int ch1 = buffer[offset + 1 + 2 * j] & 0xff;
79: int ch2 = buffer[offset + 1 + 2 * j + 1] & 0xff;
80:
81: int ch = (ch1 << 8) + ch2;
82:
83: if (ch == 0)
84: break;
85:
86: sb.append((char) ch);
87: }
88:
89: return sb.toString();
90: }
91: }
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