1 /**
2 * JDBM LICENSE v1.00
3 *
4 * Redistribution and use of this software and associated documentation
5 * ("Software"), with or without modification, are permitted provided
6 * that the following conditions are met:
7 *
8 * 1. Redistributions of source code must retain copyright
9 * statements and notices. Redistributions must also contain a
10 * copy of this document.
11 *
12 * 2. Redistributions in binary form must reproduce the
13 * above copyright notice, this list of conditions and the
14 * following disclaimer in the documentation and/or other
15 * materials provided with the distribution.
16 *
17 * 3. The name "JDBM" must not be used to endorse or promote
18 * products derived from this Software without prior written
19 * permission of Cees de Groot. For written permission,
20 * please contact cg@cdegroot.com.
21 *
22 * 4. Products derived from this Software may not be called "JDBM"
23 * nor may "JDBM" appear in their names without prior written
24 * permission of Cees de Groot.
25 *
26 * 5. Due credit should be given to the JDBM Project
27 * (http://jdbm.sourceforge.net/).
28 *
29 * THIS SOFTWARE IS PROVIDED BY THE JDBM PROJECT AND CONTRIBUTORS
30 * ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT
31 * NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
32 * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
33 * CEES DE GROOT OR ANY CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
34 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
35 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
36 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
37 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
38 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
39 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
40 * OF THE POSSIBILITY OF SUCH DAMAGE.
41 *
42 * Copyright 2001 (C) Alex Boisvert. All Rights Reserved.
43 * Contributions are Copyright (C) 2001 by their associated contributors.
44 *
45 */
46
47 package jdbm.helper;
48
49 import java.util.Comparator;
50 import java.io.Serializable;
51
52 /**
53 * Comparator for byte arrays.
54 *
55 * @author <a href="mailto:boisvert@intalio.com">Alex Boisvert</a>
56 * @version $Id: ByteArrayComparator.java,v 1.4 2002/05/31 06:33:20 boisvert Exp $
57 */
58 public final class ByteArrayComparator
59 implements Comparator, Serializable
60 {
61
62 /**
63 * Version id for serialization.
64 */
65 final static long serialVersionUID = 1L;
66
67
68 /**
69 * Compare two objects.
70 *
71 * @param obj1 First object
72 * @param obj2 Second object
73 * @return a positive integer if obj1 > obj2, 0 if obj1 == obj2,
74 * and a negative integer if obj1 < obj2
75 */
76 public int compare( Object obj1, Object obj2 )
77 {
78 if ( obj1 == null ) {
79 throw new IllegalArgumentException( "Argument 'obj1' is null" );
80 }
81
82 if ( obj2 == null ) {
83 throw new IllegalArgumentException( "Argument 'obj2' is null" );
84 }
85
86 return compareByteArray( (byte[]) obj1, (byte[]) obj2 );
87 }
88
89
90 /**
91 * Compare two byte arrays.
92 */
93 public static int compareByteArray( byte[] thisKey, byte[] otherKey )
94 {
95 int len = Math.min( thisKey.length, otherKey.length );
96
97 // compare the byte arrays
98 for ( int i=0; i<len; i++ ) {
99 if ( thisKey[i] >= 0 ) {
100 if ( otherKey[i] >= 0 ) {
101 // both positive
102 if ( thisKey[i] < otherKey[i] ) {
103 return -1;
104 } else if ( thisKey[i] > otherKey[i] ) {
105 return 1;
106 }
107 } else {
108 // otherKey is negative => greater (because MSB is 1)
109 return -1;
110 }
111 } else {
112 if ( otherKey[i] >= 0 ) {
113 // thisKey is negative => greater (because MSB is 1)
114 return 1;
115 } else {
116 // both negative
117 if ( thisKey[i] < otherKey[i] ) {
118 return -1;
119 } else if ( thisKey[i] > otherKey[i] ) {
120 return 1;
121 }
122 }
123 }
124 }
125 if ( thisKey.length == otherKey.length) {
126 return 0;
127 }
128 if ( thisKey.length < otherKey.length ) {
129 return -1;
130 }
131 return 1;
132 }
133
134 }