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1   /*
2    * Copyright (c) 1997, 2006, Oracle and/or its affiliates. All rights reserved.
3    * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4    *
5    * This code is free software; you can redistribute it and/or modify it
6    * under the terms of the GNU General Public License version 2 only, as
7    * published by the Free Software Foundation.  Oracle designates this
8    * particular file as subject to the "Classpath" exception as provided
9    * by Oracle in the LICENSE file that accompanied this code.
10   *
11   * This code is distributed in the hope that it will be useful, but WITHOUT
12   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14   * version 2 for more details (a copy is included in the LICENSE file that
15   * accompanied this code).
16   *
17   * You should have received a copy of the GNU General Public License version
18   * 2 along with this work; if not, write to the Free Software Foundation,
19   * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20   *
21   * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22   * or visit www.oracle.com if you need additional information or have any
23   * questions.
24   */
25  
26  
27  package sun.security.util;
28  
29  import java.util.Comparator;
30  
31  /**
32   * Compare two byte arrays in lexicographical order.
33   *
34   * @author D. N. Hoover
35   */
36  public class ByteArrayLexOrder implements Comparator<byte[]> {
37  
38      /**
39       * Perform lexicographical comparison of two byte arrays,
40       * regarding each byte as unsigned.  That is, compare array entries
41       * in order until they differ--the array with the smaller entry
42       * is "smaller". If array entries are
43       * equal till one array ends, then the longer array is "bigger".
44       *
45       * @param  bytes1 first byte array to compare.
46       * @param  bytes2 second byte array to compare.
47       * @return negative number if bytes1 < bytes2, 0 if bytes1 == bytes2,
48       * positive number if bytes1 > bytes2.
49       *
50       * @exception <code>ClassCastException</code>
51       * if either argument is not a byte array.
52       */
53      public final int compare( byte[] bytes1, byte[] bytes2) {
54          int diff;
55          for (int i = 0; i < bytes1.length && i < bytes2.length; i++) {
56              diff = (bytes1[i] & 0xFF) - (bytes2[i] & 0xFF);
57              if (diff != 0) {
58                  return diff;
59              }
60          }
61          // if array entries are equal till the first ends, then the
62          // longer is "bigger"
63          return bytes1.length - bytes2.length;
64      }
65  
66  
67  }