/*******************************************************************************

        copyright:      Copyright (c) 2006 Tango. All rights reserved

        license:        BSD style: see doc/license.txt for details

        version:        Initial release: Feb 2006

        author:         Regan Heath, Oskar Linde

        This module implements the SHA-1 Algorithm described by Secure Hash
        Standard, FIPS PUB 180-1, and RFC 3174 US Secure Hash Algorithm 1
        (SHA1). D. Eastlake 3rd, P. Jones. September 2001.

*******************************************************************************/

module tango.io.digest.Sha1;

private import tango.io.digest.Sha01;

public  import tango.io.digest.Digest;

/*******************************************************************************

*******************************************************************************/

final class Sha1 : Sha01
{
        /***********************************************************************

                Construct a Sha1 hash algorithm context

        ***********************************************************************/
        
        this() { }

        /***********************************************************************

                Performs the cipher on a block of data

                Params:
                data = the block of data to cipher

                Remarks:
                The actual cipher algorithm is carried out by this method on
                the passed block of data. This method is called for every
                blockSize() bytes of input data and once more with the remaining
                data padded to blockSize().

        ***********************************************************************/

        final protected override void transform(ubyte[] input)
        {
                uint A,B,C,D,E,TEMP;
                uint[16] W;
                uint s;

                bigEndian32(input,W);
                A = context[0];
                B = context[1];
                C = context[2];
                D = context[3];
                E = context[4];

                for(uint t = 0; t < 80; t++) {
                        s = t & mask;
                        if (t >= 16)
                                expand(W,s);
                        TEMP = rotateLeft(A,5) + f(t,B,C,D) + E + W[s] + K[t/20];
                        E = D; D = C; C = rotateLeft(B,30); B = A; A = TEMP;
                }

                context[0] += A;
                context[1] += B;
                context[2] += C;
                context[3] += D;
                context[4] += E;
        }

        /***********************************************************************

        ***********************************************************************/
        
        final static void expand (uint[] W, uint s)
        {
                W[s] = rotateLeft(W[(s+13)&mask] ^ W[(s+8)&mask] ^ W[(s+2)&mask] ^ W[s],1);
        }
        
}


/*******************************************************************************

*******************************************************************************/

version (UnitTest)
{
        unittest 
        {
        static char[][] strings = 
        [
                "abc",
                "abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq",
                "a",
                "0123456701234567012345670123456701234567012345670123456701234567"
        ];

        static char[][] results = 
        [
                "a9993e364706816aba3e25717850c26c9cd0d89d",
                "84983e441c3bd26ebaae4aa1f95129e5e54670f1",
                "34aa973cd4c4daa4f61eeb2bdbad27316534016f",
                "dea356a2cddd90c7a7ecedc5ebb563934f460452"
        ];

        static int[] repeat = 
        [
                1,
                1,
                1000000,
                10
        ];

        Sha1 h = new Sha1();
        
        foreach (int i, char[] s; strings) 
                {
                for(int r = 0; r < repeat[i]; r++)
                        h.update(s);
                
                char[] d = h.hexDigest();
                assert(d == results[i],":("~s~")("~d~")!=("~results[i]~")");
                }
        }
}