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     */
046    
047    package jdbm.helper;
048    
049    import java.util.Comparator;
050    import java.io.Serializable;
051    
052    import org.apache.directory.server.i18n.I18n;
053    
054    /**
055     * Comparator for byte arrays.
056     *
057     * @author <a href="mailto:boisvert@intalio.com">Alex Boisvert</a>
058     * @version $Id: ByteArrayComparator.java,v 1.4 2002/05/31 06:33:20 boisvert Exp $
059     */
060    public final class ByteArrayComparator
061        implements Comparator, Serializable
062    {
063    
064        /**
065         * Version id for serialization.
066         */
067        final static long serialVersionUID = 1L;
068    
069    
070        /**
071         * Compare two objects.
072         *
073         * @param obj1 First object
074         * @param obj2 Second object
075         * @return a positive integer if obj1 > obj2, 0 if obj1 == obj2,
076         *         and a negative integer if obj1 < obj2
077         */
078         public int compare( Object obj1, Object obj2 )
079         {
080            if ( obj1 == null ) {
081                throw new IllegalArgumentException( I18n.err( I18n.ERR_525 ) );
082            }
083    
084            if ( obj2 == null ) {
085                throw new IllegalArgumentException( I18n.err( I18n.ERR_526 ) );
086            }
087    
088            return compareByteArray( (byte[]) obj1, (byte[]) obj2 );
089         }
090    
091    
092        /**
093         * Compare two byte arrays.
094         */
095        public static int compareByteArray( byte[] thisKey, byte[] otherKey )
096        {
097            int len = Math.min( thisKey.length, otherKey.length );
098    
099            // compare the byte arrays
100            for ( int i=0; i<len; i++ ) {
101                if ( thisKey[i] >= 0 ) {
102                    if ( otherKey[i] >= 0 ) {
103                        // both positive
104                        if ( thisKey[i] < otherKey[i] ) {
105                            return -1;
106                        } else if ( thisKey[i] > otherKey[i] ) {
107                            return 1;
108                        }
109                    } else {
110                        // otherKey is negative => greater (because MSB is 1)
111                        return -1;
112                    }
113                } else {
114                    if ( otherKey[i] >= 0 ) {
115                        // thisKey is negative => greater (because MSB is 1)
116                        return 1;
117                    } else {
118                        // both negative
119                        if ( thisKey[i] < otherKey[i] ) {
120                            return -1;
121                        } else if ( thisKey[i] > otherKey[i] ) {
122                            return 1;
123                        }
124                    }
125                }
126            }
127            if ( thisKey.length == otherKey.length) {
128                return 0;
129            }
130            if ( thisKey.length < otherKey.length ) {
131                return -1;
132            }
133            return 1;
134        }
135    
136    }