ByteArrayComparator.java

/*
 * dnssecjava - a DNSSEC validating stub resolver for Java
 * Copyright (c) 2013-2015 Ingo Bauersachs
 *
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 * 
 * This file is based on work under the following copyright and permission
 * notice:
 * 
 *     Copyright (c) 2005 VeriSign. All rights reserved.
 * 
 *     Redistribution and use in source and binary forms, with or without
 *     modification, are permitted provided that the following conditions are
 *     met:
 * 
 *     1. Redistributions of source code must retain the above copyright
 *        notice, this list of conditions and the following disclaimer.
 *     2. Redistributions in binary form must reproduce the above copyright
 *        notice, this list of conditions and the following disclaimer in the
 *        documentation and/or other materials provided with the distribution.
 *     3. The name of the author may not be used to endorse or promote
 *        products derived from this software without specific prior written
 *        permission.
 * 
 *     THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 *     IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 *     WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 *     ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
 *     INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 *     (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 *     SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 *     HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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 */

package org.jitsi.dnssec.validator;

import java.util.Comparator;

/**
 * This class implements a basic comparator for byte arrays. It is primarily
 * useful for comparing RDATA portions of DNS records in doing DNSSEC canonical
 * ordering.
 */
public class ByteArrayComparator implements Comparator<Object> {
    private static final int MAX_BYTE = 0xFF;

    /** {@inheritDoc} */
    public int compare(Object o1, Object o2) {
        byte[] b1 = (byte[])o1;
        byte[] b2 = (byte[])o2;

        if (b1.length != b2.length) {
            return b1.length - b2.length;
        }

        for (int i = 0; i < b1.length; i++) {
            if (b1[i] != b2[i]) {
                return (b1[i] & MAX_BYTE) - (b2[i] & MAX_BYTE);
            }
        }

        return 0;
    }
}