1 /*
   2  * Copyright (c) 1997, 2007, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package javax.crypto;
  27 
  28 import java.security.*;
  29 import java.security.spec.*;
  30 
  31 /**
  32  * This class provides a delegate for the identity cipher - one that does not
  33  * tranform the plaintext.
  34  *
  35  * @author  Li Gong
  36  * @see NullCipher
  37  *
  38  * @since 1.4
  39  */
  40 
  41 final class NullCipherSpi extends CipherSpi {
  42 
  43     /*
  44      * Do not let anybody instantiate this directly (protected).
  45      */
  46     protected NullCipherSpi() {}
  47 
  48     public void engineSetMode(String mode) {}
  49 
  50     public void engineSetPadding(String padding) {}
  51 
  52     protected int engineGetBlockSize() {
  53         return 1;
  54     }
  55 
  56     protected int engineGetOutputSize(int inputLen) {
  57         return inputLen;
  58     }
  59 
  60     protected byte[] engineGetIV() {
  61         byte[] x = new byte[8];
  62         return x;
  63     }
  64 
  65     protected AlgorithmParameters engineGetParameters() {
  66         return null;
  67     }
  68 
  69     protected void engineInit(int mode, Key key, SecureRandom random) {}
  70 
  71     protected void engineInit(int mode, Key key,
  72                               AlgorithmParameterSpec params,
  73                               SecureRandom random) {}
  74 
  75     protected void engineInit(int mode, Key key,
  76                               AlgorithmParameters params,
  77                               SecureRandom random) {}
  78 
  79     protected byte[] engineUpdate(byte[] input, int inputOffset,
  80                                   int inputLen) {
  81         if (input == null) return null;
  82         byte[] x = new byte[inputLen];
  83         System.arraycopy(input, inputOffset, x, 0, inputLen);
  84         return x;
  85     }
  86 
  87     protected int engineUpdate(byte[] input, int inputOffset,
  88                                int inputLen, byte[] output,
  89                                int outputOffset) {
  90         if (input == null) return 0;
  91         System.arraycopy(input, inputOffset, output, outputOffset, inputLen);
  92         return inputLen;
  93     }
  94 
  95     protected byte[] engineDoFinal(byte[] input, int inputOffset,
  96                                    int inputLen)
  97     {
  98         return engineUpdate(input, inputOffset, inputLen);
  99     }
 100 
 101     protected int engineDoFinal(byte[] input, int inputOffset,
 102                                 int inputLen, byte[] output,
 103                                 int outputOffset)
 104     {
 105         return engineUpdate(input, inputOffset, inputLen,
 106                             output, outputOffset);
 107     }
 108 
 109     protected int engineGetKeySize(Key key)
 110     {
 111         return 0;
 112     }
 113 }