/*

 * Copyright (c) 1997, 2006, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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 */

/**

 * ByteArrayTagOrder: a class for comparing two DER encodings by the

 * order of their tags.

 *

 * @author D. N. Hoover

 */

package sun.security.util;

import java.util.Comparator;

public class ByteArrayTagOrder implements Comparator<byte[]> {

    /**

     * Compare two byte arrays, by the order of their tags,

     * as defined in ITU-T X.680, sec. 6.4.  (First compare

     *  tag classes, then tag numbers, ignoring the constructivity bit.)

     *

     * @param  bytes1 first byte array to compare.

     * @param  bytes2 second byte array to compare.

     * @return negative number if {@code bytes1 < bytes2},

     *         0 if {@code bytes1 == bytes2},

     *         positive number if {@code bytes1 > bytes2}.

     *

     * @exception <code>ClassCastException</code>

     * if either argument is not a byte array.

     */

    public final int compare(byte[] bytes1, byte[] bytes2) {

        // tag order is same as byte order ignoring any difference in

        // the constructivity bit (0x02)

        return (bytes1[0] | 0x20) - (bytes2[0] | 0x20);

    }

}