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 */
020 package org.apache.directory.shared.ldap.schema.comparators;
021
022
023 import java.util.Comparator;
024
025
026 /**
027 * A comparator for byte[]s.
028 *
029 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
030 * @version $Rev$
031 */
032 public class ByteArrayComparator implements Comparator<byte[]>
033 {
034 /** A static instance of this comparator */
035 public static final Comparator<byte[]> INSTANCE = new ByteArrayComparator();
036
037 /**
038 * @see java.util.Comparator#compare(java.lang.Object, java.lang.Object)
039 */
040 public int compare( byte[] b1, byte[] b2 )
041 {
042 // -------------------------------------------------------------------
043 // Handle some basis cases
044 // -------------------------------------------------------------------
045
046 if ( b1 == null )
047 {
048 return ( b2 == null ) ? 0 : -1;
049 }
050
051 if ( b2 == null )
052 {
053 return 1;
054 }
055
056 if ( b1.length == b2.length )
057 {
058 for ( int ii = 0; ii < b1.length; ii++ )
059 {
060 if ( b1[ii] > b2[ii] )
061 {
062 return 1;
063 }
064 else if ( b1[ii] < b2[ii] )
065 {
066 return -1;
067 }
068 }
069
070 return 0;
071 }
072
073 int minLength = Math.min( b1.length, b2.length );
074 for ( int ii = 0; ii < minLength; ii++ )
075 {
076 if ( b1[ii] > b2[ii] )
077 {
078 return 1;
079 }
080 else if ( b1[ii] < b2[ii] )
081 {
082 return -1;
083 }
084 }
085
086 // b2 is longer w/ b1 as prefix
087 if ( b1.length == minLength )
088 {
089 return -1;
090 }
091
092 // b1 is longer w/ b2 as prefix
093 if ( b2.length == minLength )
094 {
095 return 1;
096 }
097
098 return 0;
099 }
100 }