001: /**
002: * JDBM LICENSE v1.00
003: *
004: * Redistribution and use of this software and associated documentation
005: * ("Software"), with or without modification, are permitted provided
006: * that the following conditions are met:
007: *
008: * 1. Redistributions of source code must retain copyright
009: * statements and notices. Redistributions must also contain a
010: * copy of this document.
011: *
012: * 2. Redistributions in binary form must reproduce the
013: * above copyright notice, this list of conditions and the
014: * following disclaimer in the documentation and/or other
015: * materials provided with the distribution.
016: *
017: * 3. The name "JDBM" must not be used to endorse or promote
018: * products derived from this Software without prior written
019: * permission of Cees de Groot. For written permission,
020: * please contact cg@cdegroot.com.
021: *
022: * 4. Products derived from this Software may not be called "JDBM"
023: * nor may "JDBM" appear in their names without prior written
024: * permission of Cees de Groot.
025: *
026: * 5. Due credit should be given to the JDBM Project
027: * (http://jdbm.sourceforge.net/).
028: *
029: * THIS SOFTWARE IS PROVIDED BY THE JDBM PROJECT AND CONTRIBUTORS
030: * ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT
031: * NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
032: * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
033: * CEES DE GROOT OR ANY CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
034: * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
035: * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
036: * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
037: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
038: * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
039: * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
040: * OF THE POSSIBILITY OF SUCH DAMAGE.
041: *
042: * Copyright 2001 (C) Alex Boisvert. All Rights Reserved.
043: * Contributions are Copyright (C) 2001 by their associated contributors.
044: *
045: */package jdbm.helper;
046:
047: import java.util.Comparator;
048: import java.io.Serializable;
049:
050: /**
051: * Comparator for byte arrays.
052: *
053: * @author <a href="mailto:boisvert@intalio.com">Alex Boisvert</a>
054: * @version $Id: ByteArrayComparator.java,v 1.4 2002/05/31 06:33:20 boisvert Exp $
055: */
056: public final class ByteArrayComparator implements Comparator,
057: Serializable {
058:
059: /**
060: * Version id for serialization.
061: */
062: final static long serialVersionUID = 1L;
063:
064: /**
065: * Compare two objects.
066: *
067: * @param obj1 First object
068: * @param obj2 Second object
069: * @return a positive integer if obj1 > obj2, 0 if obj1 == obj2,
070: * and a negative integer if obj1 < obj2
071: */
072: public int compare(Object obj1, Object obj2) {
073: if (obj1 == null) {
074: throw new IllegalArgumentException(
075: "Argument 'obj1' is null");
076: }
077:
078: if (obj2 == null) {
079: throw new IllegalArgumentException(
080: "Argument 'obj2' is null");
081: }
082:
083: return compareByteArray((byte[]) obj1, (byte[]) obj2);
084: }
085:
086: /**
087: * Compare two byte arrays.
088: */
089: public static int compareByteArray(byte[] this Key, byte[] otherKey) {
090: int len = Math.min(this Key.length, otherKey.length);
091:
092: // compare the byte arrays
093: for (int i = 0; i < len; i++) {
094: if (this Key[i] >= 0) {
095: if (otherKey[i] >= 0) {
096: // both positive
097: if (this Key[i] < otherKey[i]) {
098: return -1;
099: } else if (this Key[i] > otherKey[i]) {
100: return 1;
101: }
102: } else {
103: // otherKey is negative => greater (because MSB is 1)
104: return -1;
105: }
106: } else {
107: if (otherKey[i] >= 0) {
108: // thisKey is negative => greater (because MSB is 1)
109: return 1;
110: } else {
111: // both negative
112: if (this Key[i] < otherKey[i]) {
113: return -1;
114: } else if (this Key[i] > otherKey[i]) {
115: return 1;
116: }
117: }
118: }
119: }
120: if (this Key.length == otherKey.length) {
121: return 0;
122: }
123: if (this Key.length < otherKey.length) {
124: return -1;
125: }
126: return 1;
127: }
128:
129: }
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