/**
* 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.
+ * 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();
+ this.cipher = (cipher != null) ? cipher : new NullCipher();
}
/**
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.
+ * <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 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());
+ out.write(cipher.doFinal());
+ out.flush();
+ out.close();
}
- catch (javax.crypto.BadPaddingException bpe)
+ catch (Exception cause)
{
- throw new IOException(bpe.toString());
+ IOException ioex = new IOException(String.valueOf(cause));
+ ioex.initCause(cause);
+ throw ioex;
}
- 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.
+ * @throws IOException If an I/O error occurs.
*/
public void flush() throws IOException
{
/**
* 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.
+ * @throws 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(new byte[] { (byte) b }, 0, 1);
}
/**
* 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.
+ * @throws 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 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.
+ * @throws 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;
+ out.write(cipher.update(buf, off, len));
}
}
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