gt:     if (index == M.length)
context: /* OMAC.java --
     Copyright (C) 2004, 2006 Free Software Foundation, Inc.
  
  This file is a part of GNU Classpath.
  
  GNU Classpath is free software; you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation; either version 2 of the License, or (at
  your option) any later version.
  
  GNU Classpath 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 for more details.
  
  You should have received a copy of the GNU General Public License
  along with GNU Classpath; if not, write to the Free Software
  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301
  USA
  
  Linking this library statically or dynamically with other modules is
  making a combined work based on this library.  Thus, the terms and
  conditions of the GNU General Public License cover the whole
  combination.
  
  As a special exception, the copyright holders of this library give you
  permission to link this library with independent modules to produce an
  executable, regardless of the license terms of these independent
  modules, and to copy and distribute the resulting executable under
  terms of your choice, provided that you also meet, for each linked
  independent module, the terms and conditions of the license of that
  module.  An independent module is a module which is not derived from
  or based on this library.  If you modify this library, you may extend
  this exception to your version of the library, but you are not
  obligated to do so.  If you do not wish to do so, delete this
  exception statement from your version.  */
  
  
  package gnu.javax.crypto.mac;
  
  import gnu.java.security.Configuration;
  import gnu.java.security.Registry;
  import gnu.java.security.util.Util;
  import gnu.javax.crypto.cipher.CipherFactory;
  import gnu.javax.crypto.cipher.IBlockCipher;
  import gnu.javax.crypto.mode.IMode;
  
  import java.security.InvalidKeyException;
  import java.util.Arrays;
  import java.util.HashMap;
  import java.util.Map;
  import java.util.logging.Logger;
  
  /**
   * The One-Key CBC MAC, OMAC. This message authentication code is based on a
   * block cipher in CBC mode.
   * <p>
   * References:
   * <ol>
   * <li>Tetsu Iwata and Kaoru Kurosawa, <i><a
   * href="http://crypt.cis.ibaraki.ac.jp/omac/docs/omac.pdf">OMAC: One-Key CBC
   * MAC</a></i>.</li>
   * </ol>
   */
  public class OMAC
      implements IMac
  {
    private static final Logger log = Logger.getLogger(OMAC.class.getName());
    private static final byte C1 = (byte) 0x87;
    private static final byte C2 = 0x1b;
    // Test key for OMAC-AES-128
    private static final byte[] KEY0 =
        Util.toBytesFromString("2b7e151628aed2a6abf7158809cf4f3c");
    // Test MAC for zero-length input.
    private static final byte[] DIGEST0 =
        Util.toBytesFromString("bb1d6929e95937287fa37d129b756746");
    private static Boolean valid;
    private final IBlockCipher cipher;
    private final String name;
    private IMode mode;
    private int blockSize;
    private int outputSize;
    private byte[] Lu, Lu2;
    private byte[] M;
    private byte[] Y;
    private boolean init;
    private int index;
  
    public OMAC(IBlockCipher cipher)
    {
      this.cipher = cipher;
      this.name = "OMAC-" + cipher.name();
    }
  
    public Object clone()
    {
      return new OMAC(cipher);
    }
  
    public String name()
    {
      return name;
    }
  
    public int macSize()
    {
      return outputSize;
    }
  
    public void init(Map attrib) throws InvalidKeyException
    {
      HashMap attrib2 = new HashMap();
      attrib2.put(IBlockCipher.KEY_MATERIAL, attrib.get(MAC_KEY_MATERIAL));
      cipher.reset();
      cipher.init(attrib2);
      blockSize = cipher.currentBlockSize();
      Integer os = (Integer) attrib.get(TRUNCATED_SIZE);
      if (os != null)
        {
          outputSize = os.intValue();
          if (outputSize < 0 || outputSize > blockSize)
            throw new IllegalArgumentException("truncated size out of range");
        }
      else
        outputSize = blockSize;
  
      byte[] L = new byte[blockSize];
      cipher.encryptBlock(L, 0, L, 0);
      if (Configuration.DEBUG)
        log.fine("L = " + Util.toString(L).toLowerCase());
      if (Lu != null)
        {
          Arrays.fill(Lu, (byte) 0);
          if (Lu.length != blockSize)
            Lu = new byte[blockSize];
        }
      else
        Lu = new byte[blockSize];
      if (Lu2 != null)
        {
          Arrays.fill(Lu2, (byte) 0);
          if (Lu2.length != blockSize)
            Lu2 = new byte[blockSize];
        }
      else
        Lu2 = new byte[blockSize];
  
      boolean msb = (L[0] & 0x80) != 0;
      for (int i = 0; i < blockSize; i++)
        {
          Lu[i] = (byte)(L[i] << 1 & 0xFF);
          if (i + 1 < blockSize)
            Lu[i] |= (byte)((L[i + 1] & 0x80) >> 7);
        }
      if (msb)
        {
          if (blockSize == 16)
            Lu[Lu.length - 1] ^= C1;
          else if (blockSize == 8)
            Lu[Lu.length - 1] ^= C2;
          else
            throw new IllegalArgumentException("unsupported cipher block size: "
                                               + blockSize);
        }
      if (Configuration.DEBUG)
        log.fine("Lu = " + Util.toString(Lu).toLowerCase());
      msb = (Lu[0] & 0x80) != 0;
      for (int i = 0; i < blockSize; i++)
        {
          Lu2[i] = (byte)(Lu[i] << 1 & 0xFF);
          if (i + 1 < blockSize)
            Lu2[i] |= (byte)((Lu[i + 1] & 0x80) >> 7);
        }
      if (msb)
        {
          if (blockSize == 16)
            Lu2[Lu2.length - 1] ^= C1;
          else
            Lu2[Lu2.length - 1] ^= C2;
        }
      if (Configuration.DEBUG)
        log.fine("Lu2 = " + Util.toString(Lu2).toLowerCase());
      if (M != null)
        {
          Arrays.fill(M, (byte) 0);
          if (M.length != blockSize)
            M = new byte[blockSize];
        }
      else
        M = new byte[blockSize];
      if (Y != null)
        {
          Arrays.fill(Y, (byte) 0);
          if (Y.length != blockSize)
            Y = new byte[blockSize];
        }
      else
        Y = new byte[blockSize];
  
      index = 0;
      init = true;
    }
  
    public void update(byte b)
    {
      if (! init)
        throw new IllegalStateException("not initialized");
  