md5.c

/* md5.c
 *
 * The md5 hash function.
 */

/* nettle, low-level cryptographics library
 *
 * Copyright (C) 2001 Niels Mller
 *  
 * 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., 59 Temple Place - Suite 330, Boston,
 * MA 02111-1307, USA.
 */

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

#include "md5.h"

#include "macros.h"

#include <assert.h>

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

static void
md5_transform(uint32_t *digest, const uint32_t *data);

static void
md5_block(struct md5_ctx *ctx, const uint8_t *block);

void
md5_init(struct md5_ctx *ctx)
{
  ctx->digest[0] = 0x67452301;
  ctx->digest[1] = 0xefcdab89;
  ctx->digest[2] = 0x98badcfe;
  ctx->digest[3] = 0x10325476;
  
  ctx->count_l = ctx->count_h = 0;
  ctx->index = 0;
}

void
md5_update(struct md5_ctx *ctx,
	   unsigned length,
	   const uint8_t *data)
{
  if (ctx->index)
    {
      /* Try to fill partial block */
      unsigned left = MD5_DATA_SIZE - ctx->index;
      if (length < left)
	{
	  memcpy(ctx->block + ctx->index, data, length);
	  ctx->index += length;
	  return; /* Finished */
	}