/* md5-compress.c
 *
 * The compression function for the sha1 hash function.
 *
 */

/* nettle, low-level cryptographics library
 *
 * Copyright (C) 2001, 2005 Niels Möller
 *  
 * The nettle library is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 2.1 of the License, or (at your
 * option) any later version.
 * 
 * The nettle library 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 Lesser General Public
 * License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public License
 * along with the nettle library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
 * MA 02111-1301, USA.
 */

/* Based on public domain code hacked by Colin Plumb, Andrew Kuchling, and
 * Niels Möller. */


#if HAVE_CONFIG_H
# include "config.h"
#endif

#ifndef MD5_DEBUG
# define MD5_DEBUG 0
#endif

#if MD5_DEBUG
# include <stdio.h>
# define DEBUG(i) \
  fprintf(stderr, "%2d: %8x %8x %8x %8x\n", i, a, b, c, d)
#else
# define DEBUG(i)
#endif

#include <assert.h>
#include <stdlib.h>
#include <string.h>

#include "md5.h"

#include "macros.h"

/* A block, treated as a sequence of 32-bit words. */
#define MD5_DATA_LENGTH 16

/* MD5 functions */

#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 ROUND(f, w, x, y, z, data, s) \
( w += f(x, y, z) + data,  w = w<<s | w>>(32-s),  w += x )

/* Perform the MD5 transformation on one full block of 16 32-bit
 * words.
 *
 * Compresses 20 (_MD5_DIGEST_LENGTH + MD5_DATA_LENGTH) words into 4
 * (_MD5_DIGEST_LENGTH) words. */

void
_nettle_md5_compress(uint32_t *digest, const uint8_t *input)
{
  uint32_t data[MD5_DATA_LENGTH];
  uint32_t a, b, c, d;
  unsigned i;

  for (i = 0; i < MD5_DATA_LENGTH; i++, input += 4)
    data[i] = LE_READ_UINT32(input);

  a = digest[0];
  b = digest[1];
  c = digest[2];
  d = digest[3];

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

  ROUND(F2, a, b, c, d, data[ 1] + 0xf61e2562, 5); DEBUG(16);
  ROUND(F2, d, a, b, c, data[ 6] + 0xc040b340, 9); DEBUG(17);
  ROUND(F2, c, d, a, b, data[11] + 0x265e5a51, 14);
  ROUND(F2, b, c, d, a, data[ 0] + 0xe9b6c7aa, 20);
  ROUND(F2, a, b, c, d, data[ 5] + 0xd62f105d, 5);
  ROUND(F2, d, a, b, c, data[10] + 0x02441453, 9);
  ROUND(F2, c, d, a, b, data[15] + 0xd8a1e681, 14);
  ROUND(F2, b, c, d, a, data[ 4] + 0xe7d3fbc8, 20);
  ROUND(F2, a, b, c, d, data[ 9] + 0x21e1cde6, 5);
  ROUND(F2, d, a, b, c, data[14] + 0xc33707d6, 9);
  ROUND(F2, c, d, a, b, data[ 3] + 0xf4d50d87, 14);
  ROUND(F2, b, c, d, a, data[ 8] + 0x455a14ed, 20);
  ROUND(F2, a, b, c, d, data[13] + 0xa9e3e905, 5);
  ROUND(F2, d, a, b, c, data[ 2] + 0xfcefa3f8, 9);
  ROUND(F2, c, d, a, b, data[ 7] + 0x676f02d9, 14);
  ROUND(F2, b, c, d, a, data[12] + 0x8d2a4c8a, 20); DEBUG(31);

  ROUND(F3, a, b, c, d, data[ 5] + 0xfffa3942, 4); DEBUG(32);
  ROUND(F3, d, a, b, c, data[ 8] + 0x8771f681, 11); DEBUG(33);
  ROUND(F3, c, d, a, b, data[11] + 0x6d9d6122, 16);
  ROUND(F3, b, c, d, a, data[14] + 0xfde5380c, 23);
  ROUND(F3, a, b, c, d, data[ 1] + 0xa4beea44, 4);
  ROUND(F3, d, a, b, c, data[ 4] + 0x4bdecfa9, 11);
  ROUND(F3, c, d, a, b, data[ 7] + 0xf6bb4b60, 16);
  ROUND(F3, b, c, d, a, data[10] + 0xbebfbc70, 23);
  ROUND(F3, a, b, c, d, data[13] + 0x289b7ec6, 4);
  ROUND(F3, d, a, b, c, data[ 0] + 0xeaa127fa, 11);
  ROUND(F3, c, d, a, b, data[ 3] + 0xd4ef3085, 16);
  ROUND(F3, b, c, d, a, data[ 6] + 0x04881d05, 23);
  ROUND(F3, a, b, c, d, data[ 9] + 0xd9d4d039, 4);
  ROUND(F3, d, a, b, c, data[12] + 0xe6db99e5, 11);
  ROUND(F3, c, d, a, b, data[15] + 0x1fa27cf8, 16);
  ROUND(F3, b, c, d, a, data[ 2] + 0xc4ac5665, 23); DEBUG(47);

  ROUND(F4, a, b, c, d, data[ 0] + 0xf4292244, 6); DEBUG(48);
  ROUND(F4, d, a, b, c, data[ 7] + 0x432aff97, 10); DEBUG(49);
  ROUND(F4, c, d, a, b, data[14] + 0xab9423a7, 15);
  ROUND(F4, b, c, d, a, data[ 5] + 0xfc93a039, 21);
  ROUND(F4, a, b, c, d, data[12] + 0x655b59c3, 6);
  ROUND(F4, d, a, b, c, data[ 3] + 0x8f0ccc92, 10);
  ROUND(F4, c, d, a, b, data[10] + 0xffeff47d, 15);
  ROUND(F4, b, c, d, a, data[ 1] + 0x85845dd1, 21);
  ROUND(F4, a, b, c, d, data[ 8] + 0x6fa87e4f, 6);
  ROUND(F4, d, a, b, c, data[15] + 0xfe2ce6e0, 10);
  ROUND(F4, c, d, a, b, data[ 6] + 0xa3014314, 15);
  ROUND(F4, b, c, d, a, data[13] + 0x4e0811a1, 21);
  ROUND(F4, a, b, c, d, data[ 4] + 0xf7537e82, 6);
  ROUND(F4, d, a, b, c, data[11] + 0xbd3af235, 10);
  ROUND(F4, c, d, a, b, data[ 2] + 0x2ad7d2bb, 15);
  ROUND(F4, b, c, d, a, data[ 9] + 0xeb86d391, 21); DEBUG(63);

  digest[0] += a;
  digest[1] += b;
  digest[2] += c;
  digest[3] += d;
#if MD5_DEBUG
  fprintf(stderr, "99: %8x %8x %8x %8x\n",
	  digest[0], digest[1], digest[2], digest[3]);
#endif
  
}
