using System;

namespace Obscur.Core.Cryptography.Authentication.Primitives
{
    /**
    * implementation of RipeMD see,
    * http://www.esat.kuleuven.ac.be/~bosselae/ripemd160.html
    */
    public class RipeMD160Digest
		: GeneralDigest
    {
        private const int OutputLength = 20;

        private int H0, H1, H2, H3, H4; // IV's

        private int[] X = new int[16];
        private int xOff;

        /**
        * Standard constructor
        */
        public RipeMD160Digest()
        {
            Reset();
        }

        /**
        * Copy constructor.  This will copy the state of the provided
        * message digest.
        */
        public RipeMD160Digest(RipeMD160Digest t) : base(t)
        {
            H0 = t.H0;
            H1 = t.H1;
            H2 = t.H2;
            H3 = t.H3;
            H4 = t.H4;

            Array.Copy(t.X, 0, X, 0, t.X.Length);
            xOff = t.xOff;
        }

        /// <summary>
        ///     Enumerated function identity.
        /// </summary>
        public override HashFunction Identity { get { return HashFunction.Ripemd160; } }

        public override string AlgorithmName
		{
			get { return "RIPEMD160"; }
		}

        public override int OutputSize {
            get { return OutputLength; }
        }

        internal override void ProcessWord(
            byte[] input,
            int inOff)
        {
            X[xOff++] = (input[inOff] & 0xff) | ((input[inOff + 1] & 0xff) << 8)
                | ((input[inOff + 2] & 0xff) << 16) | ((input[inOff + 3] & 0xff) << 24);

            if (xOff == 16)
            {
                ProcessBlock();
            }
        }

		internal override void ProcessLength(
            long bitLength)
        {
            if (xOff > 14)
            {
            ProcessBlock();
            }

            X[14] = (int)(bitLength & 0xffffffff);
            X[15] = (int)((ulong) bitLength >> 32);
        }

        private static void UnpackWord(
            int word,
            byte[] outBytes,
            int outOff)
        {
            outBytes[outOff]     = (byte)word;
            outBytes[outOff + 1] = (byte)((uint) word >> 8);
            outBytes[outOff + 2] = (byte)((uint) word >> 16);
            outBytes[outOff + 3] = (byte)((uint) word >> 24);
        }

        public override int DoFinal(
            byte[] output,
            int outOff)
        {
            Finish();

            UnpackWord(H0, output, outOff);
            UnpackWord(H1, output, outOff + 4);
            UnpackWord(H2, output, outOff + 8);
            UnpackWord(H3, output, outOff + 12);
            UnpackWord(H4, output, outOff + 16);

            Reset();

            return OutputLength;
        }

        /**
        * reset the chaining variables to the IV values.
        */
        public override void Reset()
        {
            base.Reset();

            H0 = unchecked((int) 0x67452301);
            H1 = unchecked((int) 0xefcdab89);
            H2 = unchecked((int) 0x98badcfe);
            H3 = unchecked((int) 0x10325476);
            H4 = unchecked((int) 0xc3d2e1f0);

            xOff = 0;

            for (int i = 0; i != X.Length; i++)
            {
                X[i] = 0;
            }
        }

        /*
        * rotate int x left n bits.
        */
        private static int RL(
            int x,
            int n)
        {
            return (x << n) | (int) ((uint) x >> (32 - n));
        }

        /*
        * f1,f2,f3,f4,f5 are the basic RipeMD160 functions.
        */

        /*
        * rounds 0-15
        */
        private static int F1(
            int x,
            int y,
            int z)
        {
            return x ^ y ^ z;
        }

        /*
        * rounds 16-31
        */
        private static int F2(
            int x,
            int y,
            int z)
        {
            return (x & y) | (~x & z);
        }

        /*
        * rounds 32-47
        */
        private static int F3(
            int x,
            int y,
            int z)
        {
            return (x | ~y) ^ z;
        }

        /*
        * rounds 48-63
        */
        private static int F4(
            int x,
            int y,
            int z)
        {
            return (x & z) | (y & ~z);
        }

        /*
        * rounds 64-79
        */
        private static int F5(
            int x,
            int y,
            int z)
        {
            return x ^ (y | ~z);
        }

        internal override void ProcessBlock()
        {
            int a, aa;
            int b, bb;
            int c, cc;
            int d, dd;
            int e, ee;

            a = aa = H0;
            b = bb = H1;
            c = cc = H2;
            d = dd = H3;
            e = ee = H4;

            //
            // Rounds 1 - 16
            //
            // left
            a = RL(a + F1(b,c,d) + X[ 0], 11) + e; c = RL(c, 10);
            e = RL(e + F1(a,b,c) + X[ 1], 14) + d; b = RL(b, 10);
            d = RL(d + F1(e,a,b) + X[ 2], 15) + c; a = RL(a, 10);
            c = RL(c + F1(d,e,a) + X[ 3], 12) + b; e = RL(e, 10);
            b = RL(b + F1(c,d,e) + X[ 4],  5) + a; d = RL(d, 10);
            a = RL(a + F1(b,c,d) + X[ 5],  8) + e; c = RL(c, 10);
            e = RL(e + F1(a,b,c) + X[ 6],  7) + d; b = RL(b, 10);
            d = RL(d + F1(e,a,b) + X[ 7],  9) + c; a = RL(a, 10);
            c = RL(c + F1(d,e,a) + X[ 8], 11) + b; e = RL(e, 10);
            b = RL(b + F1(c,d,e) + X[ 9], 13) + a; d = RL(d, 10);
            a = RL(a + F1(b,c,d) + X[10], 14) + e; c = RL(c, 10);
            e = RL(e + F1(a,b,c) + X[11], 15) + d; b = RL(b, 10);
            d = RL(d + F1(e,a,b) + X[12],  6) + c; a = RL(a, 10);
            c = RL(c + F1(d,e,a) + X[13],  7) + b; e = RL(e, 10);
            b = RL(b + F1(c,d,e) + X[14],  9) + a; d = RL(d, 10);
            a = RL(a + F1(b,c,d) + X[15],  8) + e; c = RL(c, 10);

            // right
            aa = RL(aa + F5(bb,cc,dd) + X[ 5] + unchecked((int) 0x50a28be6),  8) + ee; cc = RL(cc, 10);
            ee = RL(ee + F5(aa,bb,cc) + X[14] + unchecked((int) 0x50a28be6),  9) + dd; bb = RL(bb, 10);
            dd = RL(dd + F5(ee,aa,bb) + X[ 7] + unchecked((int) 0x50a28be6),  9) + cc; aa = RL(aa, 10);
            cc = RL(cc + F5(dd,ee,aa) + X[ 0] + unchecked((int) 0x50a28be6), 11) + bb; ee = RL(ee, 10);
            bb = RL(bb + F5(cc,dd,ee) + X[ 9] + unchecked((int) 0x50a28be6), 13) + aa; dd = RL(dd, 10);
            aa = RL(aa + F5(bb,cc,dd) + X[ 2] + unchecked((int) 0x50a28be6), 15) + ee; cc = RL(cc, 10);
            ee = RL(ee + F5(aa,bb,cc) + X[11] + unchecked((int) 0x50a28be6), 15) + dd; bb = RL(bb, 10);
            dd = RL(dd + F5(ee,aa,bb) + X[ 4] + unchecked((int) 0x50a28be6),  5) + cc; aa = RL(aa, 10);
            cc = RL(cc + F5(dd,ee,aa) + X[13] + unchecked((int) 0x50a28be6),  7) + bb; ee = RL(ee, 10);
            bb = RL(bb + F5(cc,dd,ee) + X[ 6] + unchecked((int) 0x50a28be6),  7) + aa; dd = RL(dd, 10);
            aa = RL(aa + F5(bb,cc,dd) + X[15] + unchecked((int) 0x50a28be6),  8) + ee; cc = RL(cc, 10);
            ee = RL(ee + F5(aa,bb,cc) + X[ 8] + unchecked((int) 0x50a28be6), 11) + dd; bb = RL(bb, 10);
            dd = RL(dd + F5(ee,aa,bb) + X[ 1] + unchecked((int) 0x50a28be6), 14) + cc; aa = RL(aa, 10);
            cc = RL(cc + F5(dd,ee,aa) + X[10] + unchecked((int) 0x50a28be6), 14) + bb; ee = RL(ee, 10);
            bb = RL(bb + F5(cc,dd,ee) + X[ 3] + unchecked((int) 0x50a28be6), 12) + aa; dd = RL(dd, 10);
            aa = RL(aa + F5(bb,cc,dd) + X[12] + unchecked((int) 0x50a28be6),  6) + ee; cc = RL(cc, 10);

            //
            // Rounds 16-31
            //
            // left
            e = RL(e + F2(a,b,c) + X[ 7] + unchecked((int) 0x5a827999),   7) + d; b = RL(b, 10);
            d = RL(d + F2(e,a,b) + X[ 4] + unchecked((int) 0x5a827999),   6) + c; a = RL(a, 10);
            c = RL(c + F2(d,e,a) + X[13] + unchecked((int) 0x5a827999),   8) + b; e = RL(e, 10);
            b = RL(b + F2(c,d,e) + X[ 1] + unchecked((int) 0x5a827999),  13) + a; d = RL(d, 10);
            a = RL(a + F2(b,c,d) + X[10] + unchecked((int) 0x5a827999),  11) + e; c = RL(c, 10);
            e = RL(e + F2(a,b,c) + X[ 6] + unchecked((int) 0x5a827999),   9) + d; b = RL(b, 10);
            d = RL(d + F2(e,a,b) + X[15] + unchecked((int) 0x5a827999),   7) + c; a = RL(a, 10);
            c = RL(c + F2(d,e,a) + X[ 3] + unchecked((int) 0x5a827999),  15) + b; e = RL(e, 10);
            b = RL(b + F2(c,d,e) + X[12] + unchecked((int) 0x5a827999),   7) + a; d = RL(d, 10);
            a = RL(a + F2(b,c,d) + X[ 0] + unchecked((int) 0x5a827999),  12) + e; c = RL(c, 10);
            e = RL(e + F2(a,b,c) + X[ 9] + unchecked((int) 0x5a827999),  15) + d; b = RL(b, 10);
            d = RL(d + F2(e,a,b) + X[ 5] + unchecked((int) 0x5a827999),   9) + c; a = RL(a, 10);
            c = RL(c + F2(d,e,a) + X[ 2] + unchecked((int) 0x5a827999),  11) + b; e = RL(e, 10);
            b = RL(b + F2(c,d,e) + X[14] + unchecked((int) 0x5a827999),   7) + a; d = RL(d, 10);
            a = RL(a + F2(b,c,d) + X[11] + unchecked((int) 0x5a827999),  13) + e; c = RL(c, 10);
            e = RL(e + F2(a,b,c) + X[ 8] + unchecked((int) 0x5a827999),  12) + d; b = RL(b, 10);

            // right
            ee = RL(ee + F4(aa,bb,cc) + X[ 6] + unchecked((int) 0x5c4dd124),   9) + dd; bb = RL(bb, 10);
            dd = RL(dd + F4(ee,aa,bb) + X[11] + unchecked((int) 0x5c4dd124),  13) + cc; aa = RL(aa, 10);
            cc = RL(cc + F4(dd,ee,aa) + X[ 3] + unchecked((int) 0x5c4dd124),  15) + bb; ee = RL(ee, 10);
            bb = RL(bb + F4(cc,dd,ee) + X[ 7] + unchecked((int) 0x5c4dd124),   7) + aa; dd = RL(dd, 10);
            aa = RL(aa + F4(bb,cc,dd) + X[ 0] + unchecked((int) 0x5c4dd124),  12) + ee; cc = RL(cc, 10);
            ee = RL(ee + F4(aa,bb,cc) + X[13] + unchecked((int) 0x5c4dd124),   8) + dd; bb = RL(bb, 10);
            dd = RL(dd + F4(ee,aa,bb) + X[ 5] + unchecked((int) 0x5c4dd124),   9) + cc; aa = RL(aa, 10);
            cc = RL(cc + F4(dd,ee,aa) + X[10] + unchecked((int) 0x5c4dd124),  11) + bb; ee = RL(ee, 10);
            bb = RL(bb + F4(cc,dd,ee) + X[14] + unchecked((int) 0x5c4dd124),   7) + aa; dd = RL(dd, 10);
            aa = RL(aa + F4(bb,cc,dd) + X[15] + unchecked((int) 0x5c4dd124),   7) + ee; cc = RL(cc, 10);
            ee = RL(ee + F4(aa,bb,cc) + X[ 8] + unchecked((int) 0x5c4dd124),  12) + dd; bb = RL(bb, 10);
            dd = RL(dd + F4(ee,aa,bb) + X[12] + unchecked((int) 0x5c4dd124),   7) + cc; aa = RL(aa, 10);
            cc = RL(cc + F4(dd,ee,aa) + X[ 4] + unchecked((int) 0x5c4dd124),   6) + bb; ee = RL(ee, 10);
            bb = RL(bb + F4(cc,dd,ee) + X[ 9] + unchecked((int) 0x5c4dd124),  15) + aa; dd = RL(dd, 10);
            aa = RL(aa + F4(bb,cc,dd) + X[ 1] + unchecked((int) 0x5c4dd124),  13) + ee; cc = RL(cc, 10);
            ee = RL(ee + F4(aa,bb,cc) + X[ 2] + unchecked((int) 0x5c4dd124),  11) + dd; bb = RL(bb, 10);

            //
            // Rounds 32-47
            //
            // left
            d = RL(d + F3(e,a,b) + X[ 3] + unchecked((int) 0x6ed9eba1),  11) + c; a = RL(a, 10);
            c = RL(c + F3(d,e,a) + X[10] + unchecked((int) 0x6ed9eba1),  13) + b; e = RL(e, 10);
            b = RL(b + F3(c,d,e) + X[14] + unchecked((int) 0x6ed9eba1),   6) + a; d = RL(d, 10);
            a = RL(a + F3(b,c,d) + X[ 4] + unchecked((int) 0x6ed9eba1),   7) + e; c = RL(c, 10);
            e = RL(e + F3(a,b,c) + X[ 9] + unchecked((int) 0x6ed9eba1),  14) + d; b = RL(b, 10);
            d = RL(d + F3(e,a,b) + X[15] + unchecked((int) 0x6ed9eba1),   9) + c; a = RL(a, 10);
            c = RL(c + F3(d,e,a) + X[ 8] + unchecked((int) 0x6ed9eba1),  13) + b; e = RL(e, 10);
            b = RL(b + F3(c,d,e) + X[ 1] + unchecked((int) 0x6ed9eba1),  15) + a; d = RL(d, 10);
            a = RL(a + F3(b,c,d) + X[ 2] + unchecked((int) 0x6ed9eba1),  14) + e; c = RL(c, 10);
            e = RL(e + F3(a,b,c) + X[ 7] + unchecked((int) 0x6ed9eba1),   8) + d; b = RL(b, 10);
            d = RL(d + F3(e,a,b) + X[ 0] + unchecked((int) 0x6ed9eba1),  13) + c; a = RL(a, 10);
            c = RL(c + F3(d,e,a) + X[ 6] + unchecked((int) 0x6ed9eba1),   6) + b; e = RL(e, 10);
            b = RL(b + F3(c,d,e) + X[13] + unchecked((int) 0x6ed9eba1),   5) + a; d = RL(d, 10);
            a = RL(a + F3(b,c,d) + X[11] + unchecked((int) 0x6ed9eba1),  12) + e; c = RL(c, 10);
            e = RL(e + F3(a,b,c) + X[ 5] + unchecked((int) 0x6ed9eba1),   7) + d; b = RL(b, 10);
            d = RL(d + F3(e,a,b) + X[12] + unchecked((int) 0x6ed9eba1),   5) + c; a = RL(a, 10);

            // right
            dd = RL(dd + F3(ee,aa,bb) + X[15] + unchecked((int) 0x6d703ef3),   9) + cc; aa = RL(aa, 10);
            cc = RL(cc + F3(dd,ee,aa) + X[ 5] + unchecked((int) 0x6d703ef3),   7) + bb; ee = RL(ee, 10);
            bb = RL(bb + F3(cc,dd,ee) + X[ 1] + unchecked((int) 0x6d703ef3),  15) + aa; dd = RL(dd, 10);
            aa = RL(aa + F3(bb,cc,dd) + X[ 3] + unchecked((int) 0x6d703ef3),  11) + ee; cc = RL(cc, 10);
            ee = RL(ee + F3(aa,bb,cc) + X[ 7] + unchecked((int) 0x6d703ef3),   8) + dd; bb = RL(bb, 10);
            dd = RL(dd + F3(ee,aa,bb) + X[14] + unchecked((int) 0x6d703ef3),   6) + cc; aa = RL(aa, 10);
            cc = RL(cc + F3(dd,ee,aa) + X[ 6] + unchecked((int) 0x6d703ef3),   6) + bb; ee = RL(ee, 10);
            bb = RL(bb + F3(cc,dd,ee) + X[ 9] + unchecked((int) 0x6d703ef3),  14) + aa; dd = RL(dd, 10);
            aa = RL(aa + F3(bb,cc,dd) + X[11] + unchecked((int) 0x6d703ef3),  12) + ee; cc = RL(cc, 10);
            ee = RL(ee + F3(aa,bb,cc) + X[ 8] + unchecked((int) 0x6d703ef3),  13) + dd; bb = RL(bb, 10);
            dd = RL(dd + F3(ee,aa,bb) + X[12] + unchecked((int) 0x6d703ef3),   5) + cc; aa = RL(aa, 10);
            cc = RL(cc + F3(dd,ee,aa) + X[ 2] + unchecked((int) 0x6d703ef3),  14) + bb; ee = RL(ee, 10);
            bb = RL(bb + F3(cc,dd,ee) + X[10] + unchecked((int) 0x6d703ef3),  13) + aa; dd = RL(dd, 10);
            aa = RL(aa + F3(bb,cc,dd) + X[ 0] + unchecked((int) 0x6d703ef3),  13) + ee; cc = RL(cc, 10);
            ee = RL(ee + F3(aa,bb,cc) + X[ 4] + unchecked((int) 0x6d703ef3),   7) + dd; bb = RL(bb, 10);
            dd = RL(dd + F3(ee,aa,bb) + X[13] + unchecked((int) 0x6d703ef3),   5) + cc; aa = RL(aa, 10);

            //
            // Rounds 48-63
            //
            // left
            c = RL(c + F4(d,e,a) + X[ 1] + unchecked((int) 0x8f1bbcdc),  11) + b; e = RL(e, 10);
            b = RL(b + F4(c,d,e) + X[ 9] + unchecked((int) 0x8f1bbcdc),  12) + a; d = RL(d, 10);
            a = RL(a + F4(b,c,d) + X[11] + unchecked((int) 0x8f1bbcdc), 14) + e; c = RL(c, 10);
            e = RL(e + F4(a,b,c) + X[10] + unchecked((int) 0x8f1bbcdc), 15) + d; b = RL(b, 10);
            d = RL(d + F4(e,a,b) + X[ 0] + unchecked((int) 0x8f1bbcdc), 14) + c; a = RL(a, 10);
            c = RL(c + F4(d,e,a) + X[ 8] + unchecked((int) 0x8f1bbcdc), 15) + b; e = RL(e, 10);
            b = RL(b + F4(c,d,e) + X[12] + unchecked((int) 0x8f1bbcdc),  9) + a; d = RL(d, 10);
            a = RL(a + F4(b,c,d) + X[ 4] + unchecked((int) 0x8f1bbcdc),  8) + e; c = RL(c, 10);
            e = RL(e + F4(a,b,c) + X[13] + unchecked((int) 0x8f1bbcdc),  9) + d; b = RL(b, 10);
            d = RL(d + F4(e,a,b) + X[ 3] + unchecked((int) 0x8f1bbcdc), 14) + c; a = RL(a, 10);
            c = RL(c + F4(d,e,a) + X[ 7] + unchecked((int) 0x8f1bbcdc),  5) + b; e = RL(e, 10);
            b = RL(b + F4(c,d,e) + X[15] + unchecked((int) 0x8f1bbcdc),  6) + a; d = RL(d, 10);
            a = RL(a + F4(b,c,d) + X[14] + unchecked((int) 0x8f1bbcdc),  8) + e; c = RL(c, 10);
            e = RL(e + F4(a,b,c) + X[ 5] + unchecked((int) 0x8f1bbcdc),  6) + d; b = RL(b, 10);
            d = RL(d + F4(e,a,b) + X[ 6] + unchecked((int) 0x8f1bbcdc),  5) + c; a = RL(a, 10);
            c = RL(c + F4(d,e,a) + X[ 2] + unchecked((int) 0x8f1bbcdc), 12) + b; e = RL(e, 10);

            // right
            cc = RL(cc + F2(dd,ee,aa) + X[ 8] + unchecked((int) 0x7a6d76e9),  15) + bb; ee = RL(ee, 10);
            bb = RL(bb + F2(cc,dd,ee) + X[ 6] + unchecked((int) 0x7a6d76e9),   5) + aa; dd = RL(dd, 10);
            aa = RL(aa + F2(bb,cc,dd) + X[ 4] + unchecked((int) 0x7a6d76e9),   8) + ee; cc = RL(cc, 10);
            ee = RL(ee + F2(aa,bb,cc) + X[ 1] + unchecked((int) 0x7a6d76e9),  11) + dd; bb = RL(bb, 10);
            dd = RL(dd + F2(ee,aa,bb) + X[ 3] + unchecked((int) 0x7a6d76e9),  14) + cc; aa = RL(aa, 10);
            cc = RL(cc + F2(dd,ee,aa) + X[11] + unchecked((int) 0x7a6d76e9),  14) + bb; ee = RL(ee, 10);
            bb = RL(bb + F2(cc,dd,ee) + X[15] + unchecked((int) 0x7a6d76e9),   6) + aa; dd = RL(dd, 10);
            aa = RL(aa + F2(bb,cc,dd) + X[ 0] + unchecked((int) 0x7a6d76e9),  14) + ee; cc = RL(cc, 10);
            ee = RL(ee + F2(aa,bb,cc) + X[ 5] + unchecked((int) 0x7a6d76e9),   6) + dd; bb = RL(bb, 10);
            dd = RL(dd + F2(ee,aa,bb) + X[12] + unchecked((int) 0x7a6d76e9),   9) + cc; aa = RL(aa, 10);
            cc = RL(cc + F2(dd,ee,aa) + X[ 2] + unchecked((int) 0x7a6d76e9),  12) + bb; ee = RL(ee, 10);
            bb = RL(bb + F2(cc,dd,ee) + X[13] + unchecked((int) 0x7a6d76e9),   9) + aa; dd = RL(dd, 10);
            aa = RL(aa + F2(bb,cc,dd) + X[ 9] + unchecked((int) 0x7a6d76e9),  12) + ee; cc = RL(cc, 10);
            ee = RL(ee + F2(aa,bb,cc) + X[ 7] + unchecked((int) 0x7a6d76e9),   5) + dd; bb = RL(bb, 10);
            dd = RL(dd + F2(ee,aa,bb) + X[10] + unchecked((int) 0x7a6d76e9),  15) + cc; aa = RL(aa, 10);
            cc = RL(cc + F2(dd,ee,aa) + X[14] + unchecked((int) 0x7a6d76e9),   8) + bb; ee = RL(ee, 10);

            //
            // Rounds 64-79
            //
            // left
            b = RL(b + F5(c,d,e) + X[ 4] + unchecked((int) 0xa953fd4e),  9) + a; d = RL(d, 10);
            a = RL(a + F5(b,c,d) + X[ 0] + unchecked((int) 0xa953fd4e), 15) + e; c = RL(c, 10);
            e = RL(e + F5(a,b,c) + X[ 5] + unchecked((int) 0xa953fd4e),  5) + d; b = RL(b, 10);
            d = RL(d + F5(e,a,b) + X[ 9] + unchecked((int) 0xa953fd4e), 11) + c; a = RL(a, 10);
            c = RL(c + F5(d,e,a) + X[ 7] + unchecked((int) 0xa953fd4e),  6) + b; e = RL(e, 10);
            b = RL(b + F5(c,d,e) + X[12] + unchecked((int) 0xa953fd4e),  8) + a; d = RL(d, 10);
            a = RL(a + F5(b,c,d) + X[ 2] + unchecked((int) 0xa953fd4e), 13) + e; c = RL(c, 10);
            e = RL(e + F5(a,b,c) + X[10] + unchecked((int) 0xa953fd4e), 12) + d; b = RL(b, 10);
            d = RL(d + F5(e,a,b) + X[14] + unchecked((int) 0xa953fd4e),  5) + c; a = RL(a, 10);
            c = RL(c + F5(d,e,a) + X[ 1] + unchecked((int) 0xa953fd4e), 12) + b; e = RL(e, 10);
            b = RL(b + F5(c,d,e) + X[ 3] + unchecked((int) 0xa953fd4e), 13) + a; d = RL(d, 10);
            a = RL(a + F5(b,c,d) + X[ 8] + unchecked((int) 0xa953fd4e), 14) + e; c = RL(c, 10);
            e = RL(e + F5(a,b,c) + X[11] + unchecked((int) 0xa953fd4e), 11) + d; b = RL(b, 10);
            d = RL(d + F5(e,a,b) + X[ 6] + unchecked((int) 0xa953fd4e),  8) + c; a = RL(a, 10);
            c = RL(c + F5(d,e,a) + X[15] + unchecked((int) 0xa953fd4e),  5) + b; e = RL(e, 10);
            b = RL(b + F5(c,d,e) + X[13] + unchecked((int) 0xa953fd4e),  6) + a; d = RL(d, 10);

            // right
            bb = RL(bb + F1(cc,dd,ee) + X[12],  8) + aa; dd = RL(dd, 10);
            aa = RL(aa + F1(bb,cc,dd) + X[15],  5) + ee; cc = RL(cc, 10);
            ee = RL(ee + F1(aa,bb,cc) + X[10], 12) + dd; bb = RL(bb, 10);
            dd = RL(dd + F1(ee,aa,bb) + X[ 4],  9) + cc; aa = RL(aa, 10);
            cc = RL(cc + F1(dd,ee,aa) + X[ 1], 12) + bb; ee = RL(ee, 10);
            bb = RL(bb + F1(cc,dd,ee) + X[ 5],  5) + aa; dd = RL(dd, 10);
            aa = RL(aa + F1(bb,cc,dd) + X[ 8], 14) + ee; cc = RL(cc, 10);
            ee = RL(ee + F1(aa,bb,cc) + X[ 7],  6) + dd; bb = RL(bb, 10);
            dd = RL(dd + F1(ee,aa,bb) + X[ 6],  8) + cc; aa = RL(aa, 10);
            cc = RL(cc + F1(dd,ee,aa) + X[ 2], 13) + bb; ee = RL(ee, 10);
            bb = RL(bb + F1(cc,dd,ee) + X[13],  6) + aa; dd = RL(dd, 10);
            aa = RL(aa + F1(bb,cc,dd) + X[14],  5) + ee; cc = RL(cc, 10);
            ee = RL(ee + F1(aa,bb,cc) + X[ 0], 15) + dd; bb = RL(bb, 10);
            dd = RL(dd + F1(ee,aa,bb) + X[ 3], 13) + cc; aa = RL(aa, 10);
            cc = RL(cc + F1(dd,ee,aa) + X[ 9], 11) + bb; ee = RL(ee, 10);
            bb = RL(bb + F1(cc,dd,ee) + X[11], 11) + aa; dd = RL(dd, 10);

            dd += c + H1;
            H1 = H2 + d + ee;
            H2 = H3 + e + aa;
            H3 = H4 + a + bb;
            H4 = H0 + b + cc;
            H0 = dd;

            //
            // reset the offset and clean out the word buffer.
            //
            xOff = 0;
            for (int i = 0; i != X.Length; i++)
            {
                X[i] = 0;
            }
        }
    }

}