libjava/classpath/gnu/javax/crypto/assembly/ModeStage.java

   1 /* ModeStage.java --
   2    Copyright (C) 2003, 2006 Free Software Foundation, Inc.
   3
   4 This file is a 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 of the License, or (at
   9 your option) 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; if not, write to the Free Software
  18 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301
  19 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 gnu.javax.crypto.assembly;
  40
  41 import gnu.javax.crypto.mode.IMode;
  42
  43 import java.security.InvalidKeyException;
  44 import java.util.Collections;
  45 import java.util.HashSet;
  46 import java.util.Iterator;
  47 import java.util.Map;
  48 import java.util.Set;
  49
  50 /**
  51  * <p>An {@link IMode} {@link Stage} in a {@link Cascade} Cipher chain.</p>
  52  *
  53  * <p>Such a stage wraps an implementation of a Block Cipher Mode of Operation
  54  * ({@link IMode}) to allow inclusion of such an instance in a cascade of block
  55  * ciphers.</p>
  56  *
  57  * @version $Revision: 1.1 $
  58  */
  59 class ModeStage extends Stage
  60 {
  61
  62   // Constants and variables
  63   // -------------------------------------------------------------------------
  64
  65   private IMode delegate;
  66
  67   private transient Set cachedBlockSizes;
  68
  69   // Constructor(s)
  70   // -------------------------------------------------------------------------
  71
  72   ModeStage(IMode mode, Direction forwardDirection)
  73   {
  74     super(forwardDirection);
  75
  76     delegate = mode;
  77     cachedBlockSizes = null;
  78   }
  79
  80   // Class methods
  81   // -------------------------------------------------------------------------
  82
  83   // Instance methods
  84   // -------------------------------------------------------------------------
  85
  86   public Set blockSizes()
  87   {
  88     if (cachedBlockSizes == null)
  89       {
  90         HashSet result = new HashSet();
  91         for (Iterator it = delegate.blockSizes(); it.hasNext();)
  92           {
  93             result.add(it.next());
  94           }
  95         cachedBlockSizes = Collections.unmodifiableSet(result);
  96       }
  97     return cachedBlockSizes;
  98   }
  99
 100   void initDelegate(Map attributes) throws InvalidKeyException
 101   {
 102     Direction flow = (Direction) attributes.get(DIRECTION);
 103     attributes.put(IMode.STATE,
 104                    new Integer(flow.equals(forward) ? IMode.ENCRYPTION
 105                                                    : IMode.DECRYPTION));
 106
 107     delegate.init(attributes);
 108   }
 109
 110   public int currentBlockSize() throws IllegalStateException
 111   {
 112     return delegate.currentBlockSize();
 113   }
 114
 115   void resetDelegate()
 116   {
 117     delegate.reset();
 118   }
 119
 120   void updateDelegate(byte[] in, int inOffset, byte[] out, int outOffset)
 121   {
 122     delegate.update(in, inOffset, out, outOffset);
 123   }
 124
 125   public boolean selfTest()
 126   {
 127     return delegate.selfTest();
 128   }
 129 }