| /* PaddingTransformer.java -- |
| Copyright (C) 2003, 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.assembly; |
| |
| import gnu.javax.crypto.pad.IPad; |
| import gnu.javax.crypto.pad.WrongPaddingException; |
| |
| import java.util.Map; |
| |
| /** |
| * An Adapter to use any {@link IPad} as a {@link Transformer} in an |
| * {@link Assembly}. |
| * <p> |
| * When using such a {@link Transformer}, in an {@link Assembly}, there must |
| * be at least one element behind this instance in the constructed chain; |
| * otherwise, a {@link TransformerException} is thrown at initialisation time. |
| */ |
| class PaddingTransformer |
| extends Transformer |
| { |
| private IPad delegate; |
| |
| private int outputBlockSize = 1; |
| |
| PaddingTransformer(IPad padding) |
| { |
| super(); |
| |
| this.delegate = padding; |
| } |
| |
| void initDelegate(Map attributes) throws TransformerException |
| { |
| if (tail == null) |
| { |
| IllegalStateException cause = new IllegalStateException( |
| "Padding transformer missing its tail!"); |
| throw new TransformerException("initDelegate()", cause); |
| } |
| outputBlockSize = tail.currentBlockSize(); |
| delegate.init(outputBlockSize); |
| } |
| |
| int delegateBlockSize() |
| { |
| return outputBlockSize; |
| } |
| |
| void resetDelegate() |
| { |
| delegate.reset(); |
| outputBlockSize = 1; |
| } |
| |
| byte[] updateDelegate(byte[] in, int offset, int length) |
| throws TransformerException |
| { |
| inBuffer.write(in, offset, length); |
| byte[] tmp = inBuffer.toByteArray(); |
| inBuffer.reset(); |
| byte[] result; |
| if (wired == Direction.FORWARD) // padding |
| { |
| // buffers remaining bytes from (inBuffer + in) that are less than 1 |
| // block |
| if (tmp.length < outputBlockSize) |
| { |
| inBuffer.write(tmp, 0, tmp.length); |
| result = new byte[0]; |
| } |
| else |
| { |
| int newlen = outputBlockSize * (tmp.length / outputBlockSize); |
| inBuffer.write(tmp, newlen, tmp.length - newlen); |
| result = new byte[newlen]; |
| System.arraycopy(tmp, 0, result, 0, newlen); |
| } |
| } |
| else // unpadding |
| { |
| // always keep in own buffer a max of 1 block to cater for lastUpdate |
| if (tmp.length < outputBlockSize) |
| { |
| inBuffer.write(tmp, 0, tmp.length); |
| result = new byte[0]; |
| } |
| else |
| { |
| result = new byte[tmp.length - outputBlockSize]; |
| System.arraycopy(tmp, 0, result, 0, result.length); |
| inBuffer.write(tmp, result.length, outputBlockSize); |
| } |
| } |
| return result; |
| } |
| |
| byte[] lastUpdateDelegate() throws TransformerException |
| { |
| byte[] result; |
| // process multiples of blocksize as much as possible |
| // catenate result from processing inBuffer with last-update( tail ) |
| if (wired == Direction.FORWARD) // padding |
| { |
| result = inBuffer.toByteArray(); |
| byte[] padding = delegate.pad(result, 0, result.length); |
| inBuffer.write(padding, 0, padding.length); |
| } |
| else // unpadding |
| { |
| byte[] tmp = inBuffer.toByteArray(); |
| inBuffer.reset(); |
| int realLength; |
| try |
| { |
| realLength = tmp.length; // should be outputBlockSize |
| realLength -= delegate.unpad(tmp, 0, tmp.length); |
| } |
| catch (WrongPaddingException x) |
| { |
| throw new TransformerException("lastUpdateDelegate()", x); |
| } |
| inBuffer.write(tmp, 0, realLength); |
| } |
| result = inBuffer.toByteArray(); |
| inBuffer.reset(); |
| return result; |
| } |
| } |