ByteArrayLexOrder.java

/*
 * 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
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */


package sun.security.util;

import java.util.Comparator;

/**
 * Compare two byte arrays in lexicographical order.
 *
 * @author D. N. Hoover
 */
public class ByteArrayLexOrder implements Comparator<byte[]> {

    /**
     * Perform lexicographical comparison of two byte arrays,
     * regarding each byte as unsigned.  That is, compare array entries
     * in order until they differ--the array with the smaller entry
     * is "smaller". If array entries are
     * equal till one array ends, then the longer array is "bigger".
     *
     * @param  bytes1 first byte array to compare.
     * @param  bytes2 second byte array to compare.
     * @return negative number if bytes1 < bytes2, 0 if bytes1 == bytes2,
     * positive number if bytes1 > bytes2.
     *
     * @exception <code>ClassCastException</code>
     * if either argument is not a byte array.
     */
    public final int compare( byte[] bytes1, byte[] bytes2) {
        int diff;
        for (int i = 0; i < bytes1.length && i < bytes2.length; i++) {
            diff = (bytes1[i] & 0xFF) - (bytes2[i] & 0xFF);
            if (diff != 0) {
                return diff;
            }
        }
        // if array entries are equal till the first ends, then the
        // longer is "bigger"
        return bytes1.length - bytes2.length;
    }


}