Initial Commit

iTechSharp/srcbc/crypto/digests/GeneralDigest.cs

@@ -0,0 +1,118 @@
+using System;
+
+namespace Org.BouncyCastle.Crypto.Digests
+{
+    /**
+    * base implementation of MD4 family style digest as outlined in
+    * "Handbook of Applied Cryptography", pages 344 - 347.
+    */
+    public abstract class GeneralDigest
+		: IDigest
+    {
+        private const int BYTE_LENGTH = 64;
+
+        private byte[]  xBuf;
+        private int     xBufOff;
+
+        private long    byteCount;
+
+        internal GeneralDigest()
+        {
+            xBuf = new byte[4];
+        }
+
+        internal GeneralDigest(GeneralDigest t)
+        {
+            xBuf = new byte[t.xBuf.Length];
+            Array.Copy(t.xBuf, 0, xBuf, 0, t.xBuf.Length);
+
+            xBufOff = t.xBufOff;
+            byteCount = t.byteCount;
+        }
+
+        public void Update(byte input)
+        {
+            xBuf[xBufOff++] = input;
+
+            if (xBufOff == xBuf.Length)
+            {
+                ProcessWord(xBuf, 0);
+                xBufOff = 0;
+            }
+
+            byteCount++;
+        }
+
+        public void BlockUpdate(
+            byte[]  input,
+            int     inOff,
+            int     length)
+        {
+            //
+            // fill the current word
+            //
+            while ((xBufOff != 0) && (length > 0))
+            {
+                Update(input[inOff]);
+                inOff++;
+                length--;
+            }
+
+            //
+            // process whole words.
+            //
+            while (length > xBuf.Length)
+            {
+                ProcessWord(input, inOff);
+
+                inOff += xBuf.Length;
+                length -= xBuf.Length;
+                byteCount += xBuf.Length;
+            }
+
+            //
+            // load in the remainder.
+            //
+            while (length > 0)
+            {
+                Update(input[inOff]);
+
+                inOff++;
+                length--;
+            }
+        }
+
+        public void Finish()
+        {
+            long    bitLength = (byteCount << 3);
+
+            //
+            // add the pad bytes.
+            //
+            Update((byte)128);
+
+            while (xBufOff != 0) Update((byte)0);
+            ProcessLength(bitLength);
+            ProcessBlock();
+        }
+
+        public virtual void Reset()
+        {
+            byteCount = 0;
+            xBufOff = 0;
+            for ( int i = 0; i < xBuf.Length; i++ ) xBuf[i] = 0;
+        }
+
+		public int GetByteLength()
+		{
+			return BYTE_LENGTH;
+		}
+
+		internal abstract void ProcessWord(byte[] input, int inOff);
+        internal abstract void ProcessLength(long bitLength);
+        internal abstract void ProcessBlock();
+        public abstract string AlgorithmName { get; }
+		public abstract int GetDigestSize();
+        public abstract int DoFinal(byte[] output, int outOff);
+    }
+}