1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF licenses this file
6 * to you under the Apache License, Version 2.0 (the
7 * "License"); you may not use this file except in compliance
8 * with the License. You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing,
13 * software distributed under the License is distributed on an
14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15 * KIND, either express or implied. See the License for the
16 * specific language governing permissions and limitations
17 * under the License.
18 *
19 */
20 package org.apache.directory.api.ldap.model.schema.comparators;
21
22
23 import org.apache.directory.api.ldap.model.schema.LdapComparator;
24 import org.slf4j.Logger;
25 import org.slf4j.LoggerFactory;
26
27
28 /**
29 * A class for the bitStringMatch matchingRule (RFC 4517, par. 4.2.1)
30 *
31 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
32 */
33 public class BitStringComparator extends LdapComparator<String>
34 {
35 /** The serial version UID */
36 private static final long serialVersionUID = 2L;
37
38 /** A logger for this class */
39 private static final Logger LOG = LoggerFactory.getLogger( BitStringComparator.class );
40
41
42 /**
43 * The BitStringComparator constructor. Its OID is the IntegerOrderingMatch matching
44 * rule OID.
45 *
46 * @param oid The Comparator's OID
47 */
48 public BitStringComparator( String oid )
49 {
50 super( oid );
51 }
52
53
54 /**
55 * {@inheritDoc}
56 */
57 public int compare( String bs1, String bs2 )
58 {
59 LOG.debug( "comparing BitString objects '{}' with '{}'", bs1, bs2 );
60
61 // First, shortcut the process by comparing
62 // references. If they are equals, then bs1 and bs2
63 // reference the same object
64 if ( bs1 == bs2 )
65 {
66 return 0;
67 }
68
69 // Then, deal with one of bs1 or bs2 being null
70 // Both can't be null, because then they would
71 // have been caught by the previous test
72 if ( ( bs1 == null ) || ( bs2 == null ) )
73 {
74 return bs1 == null ? -1 : 1;
75 }
76
77 // We have to get rid of 0 from left of each BitString
78 char[] array1 = bs1.toCharArray();
79 char[] array2 = bs2.toCharArray();
80
81 int pos1 = bs1.indexOf( '1' );
82 int pos2 = bs2.indexOf( '1' );
83
84 if ( pos1 == -1 )
85 {
86 if ( pos2 == -1 )
87 {
88 return 0;
89 }
90 else
91 {
92 return -1;
93 }
94 }
95 else if ( pos2 == -1 )
96 {
97 return 1;
98 }
99
100 int length1 = array1.length - pos1;
101 int length2 = array2.length - pos2;
102
103 if ( length1 == length2 )
104 {
105 for ( int i = 0; i < length1; i++ )
106 {
107 int i1 = i + pos1;
108 int i2 = i + pos2;
109
110 if ( array1[i1] < array2[i2] )
111 {
112 return -1;
113 }
114 else if ( array1[i1] > array2[i2] )
115 {
116 return 1;
117 }
118 }
119
120 return 0;
121 }
122
123 if ( length1 < length2 )
124 {
125 return -1;
126 }
127 else
128 {
129 return 1;
130 }
131 }
132 }