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ByteArrayTagOrder: a class for comparing two DER encodings by the
order of their tags.

Author:D. N. Hoover
/**
 * 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.)

Params:
  • bytes1 – first byte array to compare.
  • bytes2 – second byte array to compare.
Throws:
  •  ClassCastException
 – if either argument is not a byte array.
Returns:negative number if bytes1 < bytes2, 0 if bytes1 == bytes2, positive number if bytes1 > bytes2.
/**
     * 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);
    }


}