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      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 }
    114