/* md5.c
 *
 * Copyright (C) 2006-2009 Sawtooth Consulting Ltd.
 *
 * This file is part of CyaSSL.
 *
 * CyaSSL is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * CyaSSL is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
 */


#include "md5.h"
#ifdef NO_INLINE
    #include "misc.h"
#else
    #include "misc.c"
#endif
#include <assert.h>
#include <string.h>



#ifndef min

    static INLINE word32 min(word32 a, word32 b)
    {
        return a > b ? b : a;
    }

#endif /* min */


void InitMd5(Md5* md5)
{
    md5->digest[0] = 0x67452301L;
    md5->digest[1] = 0xefcdab89L;
    md5->digest[2] = 0x98badcfeL;
    md5->digest[3] = 0x10325476L;

    md5->buffLen = 0;
    md5->loLen   = 0;
    md5->hiLen   = 0;
}


static void Transform(Md5* md5)
{
#define F1(x, y, z) (z ^ (x & (y ^ z)))
#define F2(x, y, z) F1(z, x, y)
#define F3(x, y, z) (x ^ y ^ z)
#define F4(x, y, z) (y ^ (x | ~z))

#define MD5STEP(f, w, x, y, z, data, s) \
    w = rotlFixed(w + f(x, y, z) + data, s) + x

    /* Copy context->state[] to working vars  */
    word32 a = md5->digest[0];
    word32 b = md5->digest[1];
    word32 c = md5->digest[2];
    word32 d = md5->digest[3];

    MD5STEP(F1, a, b, c, d, md5->buffer[0]  + 0xd76aa478,  7);
    MD5STEP(F1, d, a, b, c, md5->buffer[1]  + 0xe8c7b756, 12);
    MD5STEP(F1, c, d, a, b, md5->buffer[2]  + 0x242070db, 17);
    MD5STEP(F1, b, c, d, a, md5->buffer[3]  + 0xc1bdceee, 22);
    MD5STEP(F1, a, b, c, d, md5->buffer[4]  + 0xf57c0faf,  7);
    MD5STEP(F1, d, a, b, c, md5->buffer[5]  + 0x4787c62a, 12);
    MD5STEP(F1, c, d, a, b, md5->buffer[6]  + 0xa8304613, 17);
    MD5STEP(F1, b, c, d, a, md5->buffer[7]  + 0xfd469501, 22);
    MD5STEP(F1, a, b, c, d, md5->buffer[8]  + 0x698098d8,  7);
    MD5STEP(F1, d, a, b, c, md5->buffer[9]  + 0x8b44f7af, 12);
    MD5STEP(F1, c, d, a, b, md5->buffer[10] + 0xffff5bb1, 17);
    MD5STEP(F1, b, c, d, a, md5->buffer[11] + 0x895cd7be, 22);
    MD5STEP(F1, a, b, c, d, md5->buffer[12] + 0x6b901122,  7);
    MD5STEP(F1, d, a, b, c, md5->buffer[13] + 0xfd987193, 12);
    MD5STEP(F1, c, d, a, b, md5->buffer[14] + 0xa679438e, 17);
    MD5STEP(F1, b, c, d, a, md5->buffer[15] + 0x49b40821, 22);

    MD5STEP(F2, a, b, c, d, md5->buffer[1]  + 0xf61e2562,  5);
    MD5STEP(F2, d, a, b, c, md5->buffer[6]  + 0xc040b340,  9);
    MD5STEP(F2, c, d, a, b, md5->buffer[11] + 0x265e5a51, 14);
    MD5STEP(F2, b, c, d, a, md5->buffer[0]  + 0xe9b6c7aa, 20);
    MD5STEP(F2, a, b, c, d, md5->buffer[5]  + 0xd62f105d,  5);
    MD5STEP(F2, d, a, b, c, md5->buffer[10] + 0x02441453,  9);
    MD5STEP(F2, c, d, a, b, md5->buffer[15] + 0xd8a1e681, 14);
    MD5STEP(F2, b, c, d, a, md5->buffer[4]  + 0xe7d3fbc8, 20);
    MD5STEP(F2, a, b, c, d, md5->buffer[9]  + 0x21e1cde6,  5);
    MD5STEP(F2, d, a, b, c, md5->buffer[14] + 0xc33707d6,  9);
    MD5STEP(F2, c, d, a, b, md5->buffer[3]  + 0xf4d50d87, 14);
    MD5STEP(F2, b, c, d, a, md5->buffer[8]  + 0x455a14ed, 20);
    MD5STEP(F2, a, b, c, d, md5->buffer[13] + 0xa9e3e905,  5);
    MD5STEP(F2, d, a, b, c, md5->buffer[2]  + 0xfcefa3f8,  9);
    MD5STEP(F2, c, d, a, b, md5->buffer[7]  + 0x676f02d9, 14);
    MD5STEP(F2, b, c, d, a, md5->buffer[12] + 0x8d2a4c8a, 20);

    MD5STEP(F3, a, b, c, d, md5->buffer[5]  + 0xfffa3942,  4);
    MD5STEP(F3, d, a, b, c, md5->buffer[8]  + 0x8771f681, 11);
    MD5STEP(F3, c, d, a, b, md5->buffer[11] + 0x6d9d6122, 16);
    MD5STEP(F3, b, c, d, a, md5->buffer[14] + 0xfde5380c, 23);
    MD5STEP(F3, a, b, c, d, md5->buffer[1]  + 0xa4beea44,  4);
    MD5STEP(F3, d, a, b, c, md5->buffer[4]  + 0x4bdecfa9, 11);
    MD5STEP(F3, c, d, a, b, md5->buffer[7]  + 0xf6bb4b60, 16);
    MD5STEP(F3, b, c, d, a, md5->buffer[10] + 0xbebfbc70, 23);
    MD5STEP(F3, a, b, c, d, md5->buffer[13] + 0x289b7ec6,  4);
    MD5STEP(F3, d, a, b, c, md5->buffer[0]  + 0xeaa127fa, 11);
    MD5STEP(F3, c, d, a, b, md5->buffer[3]  + 0xd4ef3085, 16);
    MD5STEP(F3, b, c, d, a, md5->buffer[6]  + 0x04881d05, 23);
    MD5STEP(F3, a, b, c, d, md5->buffer[9]  + 0xd9d4d039,  4);
    MD5STEP(F3, d, a, b, c, md5->buffer[12] + 0xe6db99e5, 11);
    MD5STEP(F3, c, d, a, b, md5->buffer[15] + 0x1fa27cf8, 16);
    MD5STEP(F3, b, c, d, a, md5->buffer[2]  + 0xc4ac5665, 23);

    MD5STEP(F4, a, b, c, d, md5->buffer[0]  + 0xf4292244,  6);
    MD5STEP(F4, d, a, b, c, md5->buffer[7]  + 0x432aff97, 10);
    MD5STEP(F4, c, d, a, b, md5->buffer[14] + 0xab9423a7, 15);
    MD5STEP(F4, b, c, d, a, md5->buffer[5]  + 0xfc93a039, 21);
    MD5STEP(F4, a, b, c, d, md5->buffer[12] + 0x655b59c3,  6);
    MD5STEP(F4, d, a, b, c, md5->buffer[3]  + 0x8f0ccc92, 10);
    MD5STEP(F4, c, d, a, b, md5->buffer[10] + 0xffeff47d, 15);
    MD5STEP(F4, b, c, d, a, md5->buffer[1]  + 0x85845dd1, 21);
    MD5STEP(F4, a, b, c, d, md5->buffer[8]  + 0x6fa87e4f,  6);
    MD5STEP(F4, d, a, b, c, md5->buffer[15] + 0xfe2ce6e0, 10);
    MD5STEP(F4, c, d, a, b, md5->buffer[6]  + 0xa3014314, 15);
    MD5STEP(F4, b, c, d, a, md5->buffer[13] + 0x4e0811a1, 21);
    MD5STEP(F4, a, b, c, d, md5->buffer[4]  + 0xf7537e82,  6);
    MD5STEP(F4, d, a, b, c, md5->buffer[11] + 0xbd3af235, 10);
    MD5STEP(F4, c, d, a, b, md5->buffer[2]  + 0x2ad7d2bb, 15);
    MD5STEP(F4, b, c, d, a, md5->buffer[9]  + 0xeb86d391, 21);
    
    /* Add the working vars back into digest state[]  */
    md5->digest[0] += a;
    md5->digest[1] += b;
    md5->digest[2] += c;
    md5->digest[3] += d;
}


static INLINE void AddLength(Md5* md5, word32 len)
{
    word32 tmp = md5->loLen;
    if ( (md5->loLen += len) < tmp)
        md5->hiLen++;                       /* carry low to high */
}


void Md5Update(Md5* md5, const byte* data, word32 len)
{
    /* do block size increments */
    byte* local = (byte*)md5->buffer;

    while (len) {
        word32 add = min(len, MD5_BLOCK_SIZE - md5->buffLen);
        memcpy(&local[md5->buffLen], data, add);

        md5->buffLen += add;
        data         += add;
        len          -= add;

        if (md5->buffLen == MD5_BLOCK_SIZE) {
            #ifdef BIG_ENDIAN_ORDER
                ByteReverseBytes(local, local, MD5_BLOCK_SIZE);
            #endif
            Transform(md5);
            AddLength(md5, MD5_BLOCK_SIZE);
            md5->buffLen = 0;
        }
    }
}


void Md5Final(Md5* md5, byte* hash)
{
    byte* local = (byte*)md5->buffer;

    AddLength(md5, md5->buffLen);               /* before adding pads */

    local[md5->buffLen++] = 0x80;  /* add 1 */

    /* pad with zeros */
    if (md5->buffLen > MD5_PAD_SIZE) {
        memset(&local[md5->buffLen], 0, MD5_BLOCK_SIZE - md5->buffLen);
        md5->buffLen += MD5_BLOCK_SIZE - md5->buffLen;

        #ifdef BIG_ENDIAN_ORDER
            ByteReverseBytes(local, local, MD5_BLOCK_SIZE);
        #endif
        Transform(md5);
        md5->buffLen = 0;
    }
    memset(&local[md5->buffLen], 0, MD5_PAD_SIZE - md5->buffLen);
   
    /* put lengths in bits */
    md5->loLen = md5->loLen << 3;
    md5->hiLen = (md5->loLen >> (8*sizeof(md5->loLen) - 3)) + 
                 (md5->hiLen << 3);

    /* store lengths */
    #ifdef BIG_ENDIAN_ORDER
        ByteReverseBytes(local, local, MD5_BLOCK_SIZE);
    #endif
    /* ! length ordering dependent on digest endian type ! */
    memcpy(&local[MD5_PAD_SIZE], &md5->loLen, sizeof(word32));
    memcpy(&local[MD5_PAD_SIZE + sizeof(word32)], &md5->hiLen, sizeof(word32));

    Transform(md5);
    #ifdef BIG_ENDIAN_ORDER
        ByteReverseWords(md5->digest, md5->digest, MD5_DIGEST_SIZE);
    #endif
    memcpy(hash, md5->digest, MD5_DIGEST_SIZE);

    InitMd5(md5);  /* reset state */
}

