001/*
002 *  Licensed to the Apache Software Foundation (ASF) under one
003 *  or more contributor license agreements.  See the NOTICE file
004 *  distributed with this work for additional information
005 *  regarding copyright ownership.  The ASF licenses this file
006 *  to you under the Apache License, Version 2.0 (the
007 *  "License"); you may not use this file except in compliance
008 *  with the License.  You may obtain a copy of the License at
009 *
010 *    http://www.apache.org/licenses/LICENSE-2.0
011 *
012 *  Unless required by applicable law or agreed to in writing,
013 *  software distributed under the License is distributed on an
014 *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 *  KIND, either express or implied.  See the License for the
016 *  specific language governing permissions and limitations
017 *  under the License.
018 *
019 */
020package org.apache.directory.mavibot.btree.comparator;
021
022
023import java.util.Comparator;
024
025
026/**
027 * Compares byte arrays.
028 *
029 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
030 */
031public class ByteArrayComparator implements Comparator<byte[]>
032{
033    /** A static instance of a ByteArrayComparator */
034    public static final ByteArrayComparator INSTANCE = new ByteArrayComparator();
035
036    /**
037     * A private constructor of the ByteArrayComparator class
038     */
039    private ByteArrayComparator()
040    {
041    }
042
043
044    /**
045     * Compare two byte arrays.
046     *
047     * @param byteArray1 First byteArray
048     * @param byteArray2 Second byteArray
049     * @return 1 if byteArray1 > byteArray2, 0 if byteArray1 == byteArray2, -1 if byteArray1 < byteArray2
050     */
051    public int compare( byte[] byteArray1, byte[] byteArray2 )
052    {
053        if ( byteArray1 == byteArray2 )
054        {
055            return 0;
056        }
057
058        if ( byteArray1 == null )
059        {
060            if ( byteArray2 == null )
061            {
062                return 0;
063            }
064            else
065            {
066                return -1;
067            }
068        }
069        else
070        {
071            if ( byteArray2 == null )
072            {
073                return 1;
074            }
075            else
076            {
077                if ( byteArray1.length < byteArray2.length )
078                {
079                    int pos = 0;
080
081                    for ( byte b1 : byteArray1 )
082                    {
083                        byte b2 = byteArray2[pos];
084
085                        if ( b1 == b2 )
086                        {
087                            pos++;
088                        }
089                        else if ( b1 < b2 )
090                        {
091                            return -1;
092                        }
093                        else
094                        {
095                            return 1;
096                        }
097                    }
098
099                    return -1;
100                }
101                else
102                {
103                    int pos = 0;
104
105                    for ( byte b2 : byteArray2 )
106                    {
107                        byte b1 = byteArray1[pos];
108
109                        if ( b1 == b2 )
110                        {
111                            pos++;
112                        }
113                        else if ( b1 < b2 )
114                        {
115                            return -1;
116                        }
117                        else
118                        {
119                            return 1;
120                        }
121                    }
122
123                    if ( pos < byteArray1.length )
124                    {
125                        return 1;
126                    }
127                    else
128                    {
129                        return 0;
130                    }
131                }
132            }
133        }
134    }
135}