1   /* NullCipherImpl.java -- implementation of NullCipher.
    2      Copyright (C) 2004  Free Software Foundation, Inc.
    3   
    4   This file is part of GNU Classpath.
    5   
    6   GNU Classpath is free software; you can redistribute it and/or modify
    7   it under the terms of the GNU General Public License as published by
    8   the Free Software Foundation; either version 2, or (at your option)
    9   any later version.
   10   
   11   GNU Classpath is distributed in the hope that it will be useful, but
   12   WITHOUT ANY WARRANTY; without even the implied warranty of
   13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   14   General Public License for more details.
   15   
   16   You should have received a copy of the GNU General Public License
   17   along with GNU Classpath; see the file COPYING.  If not, write to the
   18   Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
   19   02110-1301 USA.
   20   
   21   Linking this library statically or dynamically with other modules is
   22   making a combined work based on this library.  Thus, the terms and
   23   conditions of the GNU General Public License cover the whole
   24   combination.
   25   
   26   As a special exception, the copyright holders of this library give you
   27   permission to link this library with independent modules to produce an
   28   executable, regardless of the license terms of these independent
   29   modules, and to copy and distribute the resulting executable under
   30   terms of your choice, provided that you also meet, for each linked
   31   independent module, the terms and conditions of the license of that
   32   module.  An independent module is a module which is not derived from
   33   or based on this library.  If you modify this library, you may extend
   34   this exception to your version of the library, but you are not
   35   obligated to do so.  If you do not wish to do so, delete this
   36   exception statement from your version. */
   37   
   38   
   39   package javax.crypto;
   40   
   41   import java.security.AlgorithmParameters;
   42   import java.security.Key;
   43   import java.security.SecureRandom;
   44   import java.security.spec.AlgorithmParameterSpec;
   45   
   46   /**
   47    * Implementation of the identity cipher.
   48    */
   49   final class NullCipherImpl extends CipherSpi
   50   {
   51   
   52     // Constructor.
   53     // -------------------------------------------------------------------------
   54   
   55     NullCipherImpl()
   56     {
   57       super();
   58     }
   59   
   60     // Instance methods.
   61     // -------------------------------------------------------------------------
   62   
   63     protected void engineSetMode(String mode) { }
   64     protected void engineSetPadding(String padding) { }
   65   
   66     protected int engineGetBlockSize()
   67     {
   68       return 1;
   69     }
   70   
   71     protected int engineGetOutputSize(int inputLen)
   72     {
   73       return inputLen;
   74     }
   75   
   76     protected byte[] engineGetIV()
   77     {
   78       return null;
   79     }
   80   
   81     protected AlgorithmParameters engineGetParameters()
   82     {
   83       return null;
   84     }
   85   
   86     protected void engineInit(int mode, Key key, SecureRandom random) { }
   87     protected void engineInit(int mode, Key key, AlgorithmParameterSpec spec, SecureRandom random) { }
   88     protected void engineInit(int mode, Key key, AlgorithmParameters params, SecureRandom random) { }
   89   
   90     protected byte[] engineUpdate(byte[] input, int inputOffset, int inputLen)
   91     {
   92       if (input == null)
   93         return new byte[0];
   94       if (inputOffset < 0 || inputLen < 0 || inputOffset + inputLen > input.length)
   95         throw new ArrayIndexOutOfBoundsException();
   96       byte[] output = new byte[inputLen];
   97       System.arraycopy(input, inputOffset, output, 0, inputLen);
   98       return output;
   99     }
  100   
  101     protected int engineUpdate(byte[] input, int inputOffset, int inputLen,
  102                                byte[] output, int outputOffset)
  103       throws ShortBufferException
  104     {
  105       if (input == null)
  106         return 0;
  107       if (inputOffset < 0 || inputLen < 0 || inputOffset + inputLen > input.length
  108           || outputOffset < 0)
  109         throw new ArrayIndexOutOfBoundsException();
  110       if (output.length - outputOffset < inputLen)
  111         throw new ShortBufferException();
  112       System.arraycopy(input, inputOffset, output, outputOffset, inputLen);
  113       return inputLen;
  114     }
  115   
  116     protected byte[] engineDoFinal(byte[] input, int inputOffset, int inputLen)
  117     {
  118       return engineUpdate(input, inputOffset, inputLen);
  119     }
  120   
  121     protected int engineDoFinal(byte[] input, int inputOffset, int inputLen,
  122                                 byte[] output, int outputOffset)
  123       throws ShortBufferException
  124     {
  125       return engineUpdate(input, inputOffset, inputLen, output, outputOffset);
  126     }
  127   }