bufferedblockcipher.java

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// Decompiled by Jad v1.5.8e2. Copyright 2001 Pavel Kouznetsov.
// Jad home page: http://kpdus.tripod.com/jad.html
// Decompiler options: packimports(3) fieldsfirst ansi space 
// Source File Name:   BufferedBlockCipher.java

package org.bouncycastle.crypto;


// Referenced classes of package org.bouncycastle.crypto:
//			BlockCipher, DataLengthException, InvalidCipherTextException, CipherParameters

public class BufferedBlockCipher
{

	protected byte buf[];
	protected int bufOff;
	protected boolean forEncryption;
	protected BlockCipher cipher;
	protected boolean partialBlockOkay;
	protected boolean pgpCFB;

	protected BufferedBlockCipher()
	{
	}

	public BufferedBlockCipher(BlockCipher cipher)
	{
		this.cipher = cipher;
		buf = new byte[cipher.getBlockSize()];
		bufOff = 0;
		String name = cipher.getAlgorithmName();
		int idx = name.indexOf('/') + 1;
		pgpCFB = idx > 0 && name.startsWith("PGP", idx);
		if (pgpCFB)
			partialBlockOkay = true;
		else
			partialBlockOkay = idx > 0 && (name.startsWith("CFB", idx) || name.startsWith("OFB", idx) || name.startsWith("OpenPGP", idx));
	}

	public BlockCipher getUnderlyingCipher()
	{
		return cipher;
	}

	public void init(boolean forEncryption, CipherParameters params)
		throws IllegalArgumentException
	{
		this.forEncryption = forEncryption;
		reset();
		cipher.init(forEncryption, params);
	}

	public int getBlockSize()
	{
		return cipher.getBlockSize();
	}

	public int getUpdateOutputSize(int len)
	{
		int total = len + bufOff;
		int leftOver;
		if (pgpCFB)
			leftOver = total % buf.length - (cipher.getBlockSize() + 2);
		else
			leftOver = total % buf.length;
		return total - leftOver;
	}

	public int getOutputSize(int len)
	{
		int total = len + bufOff;
		int leftOver;
		if (pgpCFB)
		{
			leftOver = total % buf.length - (cipher.getBlockSize() + 2);
		} else
		{
			leftOver = total % buf.length;
			if (leftOver == 0)
				return total;
		}
		return (total - leftOver) + buf.length;
	}

	public int processByte(byte in, byte out[], int outOff)
		throws DataLengthException, IllegalStateException
	{
		int resultLen = 0;
		buf[bufOff++] = in;
		if (bufOff == buf.length)
		{
			resultLen = cipher.processBlock(buf, 0, out, outOff);
			bufOff = 0;
		}
		return resultLen;
	}

	public int processBytes(byte in[], int inOff, int len, byte out[], int outOff)
		throws DataLengthException, IllegalStateException
	{
		if (len < 0)
			throw new IllegalArgumentException("Can't have a negative input length!");
		int blockSize = getBlockSize();
		int length = getUpdateOutputSize(len);
		if (length > 0 && outOff + length > out.length)
			throw new DataLengthException("output buffer too short");
		int resultLen = 0;
		int gapLen = buf.length - bufOff;
		if (len > gapLen)
		{
			System.arraycopy(in, inOff, buf, bufOff, gapLen);
			resultLen += cipher.processBlock(buf, 0, out, outOff);
			bufOff = 0;
			len -= gapLen;
			for (inOff += gapLen; len > buf.length; inOff += blockSize)
			{
				resultLen += cipher.processBlock(in, inOff, out, outOff + resultLen);
				len -= blockSize;
			}

		}
		System.arraycopy(in, inOff, buf, bufOff, len);
		bufOff += len;
		if (bufOff == buf.length)
		{
			resultLen += cipher.processBlock(buf, 0, out, outOff + resultLen);
			bufOff = 0;
		}
		return resultLen;
	}

	public int doFinal(byte out[], int outOff)
		throws DataLengthException, IllegalStateException, InvalidCipherTextException
	{
		int resultLen = 0;
		if (outOff + bufOff > out.length)
			throw new DataLengthException("output buffer too short for doFinal()");
		if (bufOff != 0 && partialBlockOkay)
		{
			cipher.processBlock(buf, 0, buf, 0);
			resultLen = bufOff;
			bufOff = 0;
			System.arraycopy(buf, 0, out, outOff, resultLen);
		} else
		if (bufOff != 0)
			throw new DataLengthException("data not block size aligned");
		reset();
		return resultLen;
	}

	public void reset()
	{
		for (int i = 0; i < buf.length; i++)
			buf[i] = 0;

		bufOff = 0;
		cipher.reset();
	}
}