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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 /**
     28  * ByteArrayTagOrder: a class for comparing two DER encodings by the
     29  * order of their tags.
     30  *
     31  * @author D. N. Hoover
     32  */
     33 
     34 package sun.security.util;
     35 
     36 import java.util.Comparator;
     37 
     38 public class ByteArrayTagOrder implements Comparator<byte[]> {
     39 
     40     /**
     41      * Compare two byte arrays, by the order of their tags,
     42      * as defined in ITU-T X.680, sec. 6.4.  (First compare
     43      *  tag classes, then tag numbers, ignoring the constructivity bit.)
     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 
     54     public final int compare(byte[] bytes1, byte[] bytes2) {
     55         // tag order is same as byte order ignoring any difference in
     56         // the constructivity bit (0x02)
     57         return (bytes1[0] | 0x20) - (bytes2[0] | 0x20);
     58     }
     59 
     60 
     61 }
     62