| /* CipherOutputStream.java -- Filters output through a cipher. |
| Copyright (C) 2004 Free Software Foundation, Inc. |
| |
| This file is 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, 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; see the file COPYING. If not, write to the |
| Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
| 02111-1307 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 javax.crypto; |
| |
| import java.io.FilterOutputStream; |
| import java.io.IOException; |
| import java.io.OutputStream; |
| |
| /** |
| * A filtered output stream that transforms data written to it with a |
| * {@link Cipher} before sending it to the underlying output stream. |
| * |
| * @author Casey Marshall (csm@gnu.org) |
| */ |
| public class CipherOutputStream extends FilterOutputStream |
| { |
| |
| // Fields. |
| // ------------------------------------------------------------------------ |
| |
| /** The underlying cipher. */ |
| private Cipher cipher; |
| |
| private byte[][] inBuffer; |
| |
| private int inLength; |
| |
| private byte[] outBuffer; |
| |
| private static final int FIRST_TIME = 0; |
| private static final int SECOND_TIME = 1; |
| private static final int SEASONED = 2; |
| private int state; |
| |
| /** True if the cipher is a stream cipher (blockSize == 1) */ |
| private boolean isStream; |
| |
| // Constructors. |
| // ------------------------------------------------------------------------ |
| |
| /** |
| * Create a new cipher output stream. The cipher argument must have |
| * already been initialized. |
| * |
| * @param out The sink for transformed data. |
| * @param cipher The cipher to transform data with. |
| */ |
| public CipherOutputStream(OutputStream out, Cipher cipher) |
| { |
| super(out); |
| if (cipher != null) |
| { |
| this.cipher = cipher; |
| if (!(isStream = cipher.getBlockSize() == 1)) |
| { |
| inBuffer = new byte[2][]; |
| inBuffer[0] = new byte[cipher.getBlockSize()]; |
| inBuffer[1] = new byte[cipher.getBlockSize()]; |
| inLength = 0; |
| state = FIRST_TIME; |
| } |
| } |
| else |
| this.cipher = new NullCipher(); |
| } |
| |
| /** |
| * Create a cipher output stream with no cipher. |
| * |
| * @param out The sink for transformed data. |
| */ |
| protected CipherOutputStream(OutputStream out) |
| { |
| super(out); |
| } |
| |
| // Instance methods. |
| // ------------------------------------------------------------------------ |
| |
| /** |
| * Close this output stream, and the sink output stream. |
| * |
| * <p>This method will first invoke the {@link Cipher#doFinal()} |
| * method of the underlying {@link Cipher}, and writes the output of |
| * that method to the sink output stream. |
| * |
| * @throws java.io.IOException If an I/O error occurs, or if an error |
| * is caused by finalizing the transformation. |
| */ |
| public void close() throws IOException |
| { |
| try |
| { |
| int len; |
| if (state != FIRST_TIME) |
| { |
| len = cipher.update(inBuffer[0], 0, inBuffer[0].length, outBuffer); |
| out.write(outBuffer, 0, len); |
| } |
| len = cipher.doFinal(inBuffer[0], 0, inLength, outBuffer); |
| out.write(outBuffer, 0, len); |
| } |
| catch (javax.crypto.IllegalBlockSizeException ibse) |
| { |
| throw new IOException(ibse.toString()); |
| } |
| catch (javax.crypto.BadPaddingException bpe) |
| { |
| throw new IOException(bpe.toString()); |
| } |
| catch (ShortBufferException sbe) |
| { |
| throw new IOException(sbe.toString()); |
| } |
| out.flush(); |
| out.close(); |
| } |
| |
| /** |
| * Flush any pending output. |
| * |
| * @throws java.io.IOException If an I/O error occurs. |
| */ |
| public void flush() throws IOException |
| { |
| out.flush(); |
| } |
| |
| /** |
| * Write a single byte to the output stream. |
| * |
| * @param b The next byte. |
| * @throws java.io.IOException If an I/O error occurs, or if the |
| * underlying cipher is not in the correct state to transform |
| * data. |
| */ |
| public void write(int b) throws IOException |
| { |
| if (isStream) |
| { |
| byte[] buf = new byte[] { (byte) b }; |
| try |
| { |
| cipher.update(buf, 0, 1, buf, 0); |
| } |
| catch (ShortBufferException sbe) |
| { |
| throw new IOException(sbe.toString()); |
| } |
| out.write(buf); |
| return; |
| } |
| inBuffer[1][inLength++] = (byte) b; |
| if (inLength == inBuffer[1].length) |
| process(); |
| } |
| |
| /** |
| * Write a byte array to the output stream. |
| * |
| * @param buf The next bytes. |
| * @throws java.io.IOException If an I/O error occurs, or if the |
| * underlying cipher is not in the correct state to transform |
| * data. |
| */ |
| public void write(byte[] buf) throws IOException |
| { |
| write(buf, 0, buf.length); |
| } |
| |
| /** |
| * Write a portion of a byte array to the output stream. |
| * |
| * @param buf The next bytes. |
| * @param off The offset in the byte array to start. |
| * @param len The number of bytes to write. |
| * @throws java.io.IOException If an I/O error occurs, or if the |
| * underlying cipher is not in the correct state to transform |
| * data. |
| */ |
| public void write(byte[] buf, int off, int len) throws IOException |
| { |
| if (isStream) |
| { |
| out.write(cipher.update(buf, off, len)); |
| return; |
| } |
| int count = 0; |
| while (count < len) |
| { |
| int l = Math.min(inBuffer[1].length - inLength, len - count); |
| System.arraycopy(buf, off+count, inBuffer[1], inLength, l); |
| count += l; |
| inLength += l; |
| if (inLength == inBuffer[1].length) |
| process(); |
| } |
| } |
| |
| // Own method. |
| // ------------------------------------------------------------------------- |
| |
| private void process() throws IOException |
| { |
| if (state == SECOND_TIME) |
| { |
| state = SEASONED; |
| } |
| else |
| { |
| byte[] temp = inBuffer[0]; |
| inBuffer[0] = inBuffer[1]; |
| inBuffer[1] = temp; |
| } |
| if (state == FIRST_TIME) |
| { |
| inLength = 0; |
| state = SECOND_TIME; |
| return; |
| } |
| try |
| { |
| cipher.update(inBuffer[0], 0, inBuffer[0].length, outBuffer); |
| } |
| catch (ShortBufferException sbe) |
| { |
| throw new IOException(sbe.toString()); |
| } |
| out.write(outBuffer); |
| inLength = 0; |
| } |
| } |