1 files changed, 377 insertions, 0 deletions
diff --git a/crypto/src/crypto/BufferedBlockCipher.cs b/crypto/src/crypto/BufferedBlockCipher.cs
new file mode 100644
index 000000000..3a98798a2
--- /dev/null
+++ b/crypto/src/crypto/BufferedBlockCipher.cs
@@ -0,0 +1,377 @@
+using System;
+using System.Diagnostics;
+
+using Org.BouncyCastle.Crypto.Parameters;
+
+namespace Org.BouncyCastle.Crypto
+{
+	/**
+	* A wrapper class that allows block ciphers to be used to process data in
+	* a piecemeal fashion. The BufferedBlockCipher outputs a block only when the
+	* buffer is full and more data is being added, or on a doFinal.
+	* <p>
+	* Note: in the case where the underlying cipher is either a CFB cipher or an
+	* OFB one the last block may not be a multiple of the block size.
+	* </p>
+	*/
+	public class BufferedBlockCipher
+		: BufferedCipherBase
+	{
+		internal byte[]			buf;
+		internal int			bufOff;
+		internal bool			forEncryption;
+		internal IBlockCipher	cipher;
+
+		/**
+		* constructor for subclasses
+		*/
+		protected BufferedBlockCipher()
+		{
+		}
+
+		/**
+		* Create a buffered block cipher without padding.
+		*
+		* @param cipher the underlying block cipher this buffering object wraps.
+		* false otherwise.
+		*/
+		public BufferedBlockCipher(
+			IBlockCipher cipher)
+		{
+			if (cipher == null)
+				throw new ArgumentNullException("cipher");
+
+			this.cipher = cipher;
+			buf = new byte[cipher.GetBlockSize()];
+			bufOff = 0;
+		}
+
+		public override string AlgorithmName
+		{
+			get { return cipher.AlgorithmName; }
+		}
+
+		/**
+		* initialise the cipher.
+		*
+		* @param forEncryption if true the cipher is initialised for
+		*  encryption, if false for decryption.
+		* @param param the key and other data required by the cipher.
+		* @exception ArgumentException if the parameters argument is
+		* inappropriate.
+		*/
+		// Note: This doubles as the Init in the event that this cipher is being used as an IWrapper
+		public override void Init(
+			bool				forEncryption,
+			ICipherParameters	parameters)
+		{
+			this.forEncryption = forEncryption;
+
+            ParametersWithRandom pwr = parameters as ParametersWithRandom;
+            if (pwr != null)
+                parameters = pwr.Parameters;
+
+            Reset();
+
+			cipher.Init(forEncryption, parameters);
+		}
+
+		/**
+		* return the blocksize for the underlying cipher.
+		*
+		* @return the blocksize for the underlying cipher.
+		*/
+		public override int GetBlockSize()
+		{
+			return cipher.GetBlockSize();
+		}
+
+		/**
+		* return the size of the output buffer required for an update
+		* an input of len bytes.
+		*
+		* @param len the length of the input.
+		* @return the space required to accommodate a call to update
+		* with len bytes of input.
+		*/
+		public override int GetUpdateOutputSize(
+			int length)
+		{
+			int total = length + bufOff;
+			int leftOver = total % buf.Length;
+			return total - leftOver;
+		}
+
+		/**
+		* return the size of the output buffer required for an update plus a
+		* doFinal with an input of len bytes.
+		*
+		* @param len the length of the input.
+		* @return the space required to accommodate a call to update and doFinal
+		* with len bytes of input.
+		*/
+		public override int GetOutputSize(
+			int length)
+		{
+			// Note: Can assume IsPartialBlockOkay is true for purposes of this calculation
+			return length + bufOff;
+		}
+
+		/**
+		* process a single byte, producing an output block if neccessary.
+		*
+		* @param in the input byte.
+		* @param out the space for any output that might be produced.
+		* @param outOff the offset from which the output will be copied.
+		* @return the number of output bytes copied to out.
+		* @exception DataLengthException if there isn't enough space in out.
+		* @exception InvalidOperationException if the cipher isn't initialised.
+		*/
+		public override int ProcessByte(
+			byte	input,
+			byte[]	output,
+			int		outOff)
+		{
+			buf[bufOff++] = input;
+
+			if (bufOff == buf.Length)
+			{
+				if ((outOff + buf.Length) > output.Length)
+					throw new DataLengthException("output buffer too short");
+
+				bufOff = 0;
+				return cipher.ProcessBlock(buf, 0, output, outOff);
+			}
+
+			return 0;
+		}
+
+		public override byte[] ProcessByte(
+			byte input)
+		{
+			int outLength = GetUpdateOutputSize(1);
+
+			byte[] outBytes = outLength > 0 ? new byte[outLength] : null;
+
+			int pos = ProcessByte(input, outBytes, 0);
+
+			if (outLength > 0 && pos < outLength)
+			{
+				byte[] tmp = new byte[pos];
+				Array.Copy(outBytes, 0, tmp, 0, pos);
+				outBytes = tmp;
+			}
+
+			return outBytes;
+		}
+
+		public override byte[] ProcessBytes(
+			byte[]	input,
+			int		inOff,
+			int		length)
+		{
+			if (input == null)
+				throw new ArgumentNullException("input");
+			if (length < 1)
+				return null;
+
+			int outLength = GetUpdateOutputSize(length);
+
+			byte[] outBytes = outLength > 0 ? new byte[outLength] : null;
+
+			int pos = ProcessBytes(input, inOff, length, outBytes, 0);
+
+			if (outLength > 0 && pos < outLength)
+			{
+				byte[] tmp = new byte[pos];
+				Array.Copy(outBytes, 0, tmp, 0, pos);
+				outBytes = tmp;
+			}
+
+			return outBytes;
+		}
+
+		/**
+		* process an array of bytes, producing output if necessary.
+		*
+		* @param in the input byte array.
+		* @param inOff the offset at which the input data starts.
+		* @param len the number of bytes to be copied out of the input array.
+		* @param out the space for any output that might be produced.
+		* @param outOff the offset from which the output will be copied.
+		* @return the number of output bytes copied to out.
+		* @exception DataLengthException if there isn't enough space in out.
+		* @exception InvalidOperationException if the cipher isn't initialised.
+		*/
+		public override int ProcessBytes(
+			byte[]	input,
+			int		inOff,
+			int		length,
+			byte[]	output,
+			int		outOff)
+		{
+			if (length < 1)
+			{
+				if (length < 0)
+					throw new ArgumentException("Can't have a negative input length!");
+
+				return 0;
+			}
+
+			int blockSize = GetBlockSize();
+			int outLength = GetUpdateOutputSize(length);
+
+			if (outLength > 0)
+			{
+				if ((outOff + outLength) > output.Length)
+				{
+					throw new DataLengthException("output buffer too short");
+				}
+			}
+
+			int resultLen = 0;
+			int gapLen = buf.Length - bufOff;
+			if (length > gapLen)
+			{
+				Array.Copy(input, inOff, buf, bufOff, gapLen);
+				resultLen += cipher.ProcessBlock(buf, 0, output, outOff);
+				bufOff = 0;
+				length -= gapLen;
+				inOff += gapLen;
+				while (length > buf.Length)
+				{
+					resultLen += cipher.ProcessBlock(input, inOff, output, outOff + resultLen);
+					length -= blockSize;
+					inOff += blockSize;
+				}
+			}
+			Array.Copy(input, inOff, buf, bufOff, length);
+			bufOff += length;
+			if (bufOff == buf.Length)
+			{
+				resultLen += cipher.ProcessBlock(buf, 0, output, outOff + resultLen);
+				bufOff = 0;
+			}
+			return resultLen;
+		}
+
+		public override byte[] DoFinal()
+		{
+			byte[] outBytes = EmptyBuffer;
+
+			int length = GetOutputSize(0);
+			if (length > 0)
+			{
+				outBytes = new byte[length];
+
+				int pos = DoFinal(outBytes, 0);
+				if (pos < outBytes.Length)
+				{
+					byte[] tmp = new byte[pos];
+					Array.Copy(outBytes, 0, tmp, 0, pos);
+					outBytes = tmp;
+				}
+			}
+			else
+			{
+				Reset();
+			}
+
+			return outBytes;
+		}
+
+		public override byte[] DoFinal(
+			byte[]	input,
+			int		inOff,
+			int		inLen)
+		{
+			if (input == null)
+				throw new ArgumentNullException("input");
+
+			int length = GetOutputSize(inLen);
+
+			byte[] outBytes = EmptyBuffer;
+
+			if (length > 0)
+			{
+				outBytes = new byte[length];
+
+				int pos = (inLen > 0)
+					?	ProcessBytes(input, inOff, inLen, outBytes, 0)
+					:	0;
+
+				pos += DoFinal(outBytes, pos);
+
+				if (pos < outBytes.Length)
+				{
+					byte[] tmp = new byte[pos];
+					Array.Copy(outBytes, 0, tmp, 0, pos);
+					outBytes = tmp;
+				}
+			}
+			else
+			{
+				Reset();
+			}
+
+			return outBytes;
+		}
+
+		/**
+		* Process the last block in the buffer.
+		*
+		* @param out the array the block currently being held is copied into.
+		* @param outOff the offset at which the copying starts.
+		* @return the number of output bytes copied to out.
+		* @exception DataLengthException if there is insufficient space in out for
+		* the output, or the input is not block size aligned and should be.
+		* @exception InvalidOperationException if the underlying cipher is not
+		* initialised.
+		* @exception InvalidCipherTextException if padding is expected and not found.
+		* @exception DataLengthException if the input is not block size
+		* aligned.
+		*/
+		public override int DoFinal(
+			byte[]	output,
+			int		outOff)
+		{
+			try
+			{
+				if (bufOff != 0)
+				{
+					if (!cipher.IsPartialBlockOkay)
+					{
+						throw new DataLengthException("data not block size aligned");
+					}
+	
+					if (outOff + bufOff > output.Length)
+					{
+						throw new DataLengthException("output buffer too short for DoFinal()");
+					}
+	
+					// NB: Can't copy directly, or we may write too much output
+					cipher.ProcessBlock(buf, 0, buf, 0);
+					Array.Copy(buf, 0, output, outOff, bufOff);
+				}
+
+				return bufOff;
+			}
+			finally
+			{
+				Reset();
+			}
+		}
+
+		/**
+		* Reset the buffer and cipher. After resetting the object is in the same
+		* state as it was after the last init (if there was one).
+		*/
+		public override void Reset()
+		{
+			Array.Clear(buf, 0, buf.Length);
+			bufOff = 0;
+
+			cipher.Reset();
+		}
+	}
+}