/* MD5C.C - RSA Data Security, Inc., MD5 message-digest algorithm
 */

/* Copyright (C) 1991-2, RSA Data Security, Inc. Created 1991. All
   rights reserved.

   License to copy and use this software is granted provided that it
   is identified as the "RSA Data Security, Inc. MD5 Message-Digest
   Algorithm" in all material mentioning or referencing this software
   or this function.

   License is also granted to make and use derivative works provided
   that such works are identified as "derived from the RSA Data
   Security, Inc. MD5 Message-Digest Algorithm" in all material
   mentioning or referencing the derived work.

   RSA Data Security, Inc. makes no representations concerning either
   the merchantability of this software or the suitability of this
   software for any particular purpose. It is provided "as is"
   without express or implied warranty of any kind.

   These notices must be retained in any copies of any part of this
   documentation and/or software.
 */

#include <mix/aes.h>

#define S11 7
#define S12 12
#define S13 17
#define S14 22
#define S21 5
#define S22 9
#define S23 14
#define S24 20
#define S31 4
#define S32 11
#define S33 16
#define S34 23
#define S41 6
#define S42 10
#define S43 15
#define S44 21

static unsigned char PADDING[64] =
{
  0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
};

/* F, G, H and I are basic MD5 functions.
 */
#define F(x, y, z) (((x) & (y)) | ((~x) & (z)))
#define G(x, y, z) (((x) & (z)) | ((y) & (~z)))
#define H(x, y, z) ((x) ^ (y) ^ (z))
#define I(x, y, z) ((y) ^ ((x) | (~z)))

/* ROTATE_LEFT rotates x left n bits.
 */
#define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32-(n))))

/* FF, GG, HH, and II transformations for rounds 1, 2, 3, and 4.
   Rotation is separate from addition to prevent recomputation.
 */
#define FF(a, b, c, d, x, s, ac) { \
 (a) += F ((b), (c), (d)) + (x) + (unsigned long int)(ac); \
 (a) = ROTATE_LEFT ((a), (s)); \
 (a) += (b); \
  }
#define GG(a, b, c, d, x, s, ac) { \
 (a) += G ((b), (c), (d)) + (x) + (unsigned long int)(ac); \
 (a) = ROTATE_LEFT ((a), (s)); \
 (a) += (b); \
  }
#define HH(a, b, c, d, x, s, ac) { \
 (a) += H ((b), (c), (d)) + (x) + (unsigned long int)(ac); \
 (a) = ROTATE_LEFT ((a), (s)); \
 (a) += (b); \
  }
#define II(a, b, c, d, x, s, ac) { \
 (a) += I ((b), (c), (d)) + (x) + (unsigned long int)(ac); \
 (a) = ROTATE_LEFT ((a), (s)); \
 (a) += (b); \
  }

void 
MD5Init(MD5_CTX * context)
{
  context->count[0] = context->count[1] = 0;
  context->state[0] = 0x67452301;
  context->state[1] = 0xefcdab89;
  context->state[2] = 0x98badcfe;
  context->state[3] = 0x10325476;
}

void 
MD5Update(MD5_CTX * context, const unsigned char *input, unsigned int inputLen)
{
  unsigned int i, index, partLen;

  index = (unsigned int) ((context->count[0] >> 3) & 0x3F);

  if ((context->count[0] += ((unsigned long int) inputLen << 3))
      < ((unsigned long int) inputLen << 3))
    context->count[1]++;
  context->count[1] += ((unsigned long int) inputLen >> 29);

  partLen = 64 - index;

  if (inputLen >= partLen)
    {
      memcpy
	((char *) &context->buffer[index], (char *) input, partLen);
      MD5Transform(context->state, context->buffer);

      for (i = partLen; i + 63 < inputLen; i += 64)
	MD5Transform(context->state, &input[i]);

      index = 0;
    }
  else
    i = 0;

  memcpy
    ((char *) &context->buffer[index], (char *) &input[i],
     inputLen - i);
}

void 
MD5Final(unsigned char digest[16], MD5_CTX * context)
{
  unsigned char bits[8];
  unsigned int index, padLen;

  md5Encode(bits, context->count, 8);
  index = (unsigned int) ((context->count[0] >> 3) & 0x3f);
  padLen = (index < 56) ? (56 - index) : (120 - index);
  MD5Update(context, PADDING, padLen);
  MD5Update(context, bits, 8);
  md5Encode(digest, context->state, 16);
  memset((char *) context, 0, sizeof(*context));
}

void 
MD5Transform(unsigned long int state[4], const unsigned char block[64])
{
  unsigned long int a = state[0], b = state[1], c = state[2], d = state[3],
    x[16];

  md5Decode(x, block, 64);

  /* Round 1 */
  FF(a, b, c, d, x[0], S11, 0xd76aa478);	/* 1 */
  FF(d, a, b, c, x[1], S12, 0xe8c7b756);	/* 2 */
  FF(c, d, a, b, x[2], S13, 0x242070db);	/* 3 */
  FF(b, c, d, a, x[3], S14, 0xc1bdceee);	/* 4 */
  FF(a, b, c, d, x[4], S11, 0xf57c0faf);	/* 5 */
  FF(d, a, b, c, x[5], S12, 0x4787c62a);	/* 6 */
  FF(c, d, a, b, x[6], S13, 0xa8304613);	/* 7 */
  FF(b, c, d, a, x[7], S14, 0xfd469501);	/* 8 */
  FF(a, b, c, d, x[8], S11, 0x698098d8);	/* 9 */
  FF(d, a, b, c, x[9], S12, 0x8b44f7af);	/* 10 */
  FF(c, d, a, b, x[10], S13, 0xffff5bb1);	/* 11 */
  FF(b, c, d, a, x[11], S14, 0x895cd7be);	/* 12 */
  FF(a, b, c, d, x[12], S11, 0x6b901122);	/* 13 */
  FF(d, a, b, c, x[13], S12, 0xfd987193);	/* 14 */
  FF(c, d, a, b, x[14], S13, 0xa679438e);	/* 15 */
  FF(b, c, d, a, x[15], S14, 0x49b40821);	/* 16 */

  /* Round 2 */
  GG(a, b, c, d, x[1], S21, 0xf61e2562);	/* 17 */
  GG(d, a, b, c, x[6], S22, 0xc040b340);	/* 18 */
  GG(c, d, a, b, x[11], S23, 0x265e5a51);	/* 19 */
  GG(b, c, d, a, x[0], S24, 0xe9b6c7aa);	/* 20 */
  GG(a, b, c, d, x[5], S21, 0xd62f105d);	/* 21 */
  GG(d, a, b, c, x[10], S22, 0x2441453);	/* 22 */
  GG(c, d, a, b, x[15], S23, 0xd8a1e681);	/* 23 */
  GG(b, c, d, a, x[4], S24, 0xe7d3fbc8);	/* 24 */
  GG(a, b, c, d, x[9], S21, 0x21e1cde6);	/* 25 */
  GG(d, a, b, c, x[14], S22, 0xc33707d6);	/* 26 */
  GG(c, d, a, b, x[3], S23, 0xf4d50d87);	/* 27 */
  GG(b, c, d, a, x[8], S24, 0x455a14ed);	/* 28 */
  GG(a, b, c, d, x[13], S21, 0xa9e3e905);	/* 29 */
  GG(d, a, b, c, x[2], S22, 0xfcefa3f8);	/* 30 */
  GG(c, d, a, b, x[7], S23, 0x676f02d9);	/* 31 */
  GG(b, c, d, a, x[12], S24, 0x8d2a4c8a);	/* 32 */

  /* Round 3 */
  HH(a, b, c, d, x[5], S31, 0xfffa3942);	/* 33 */
  HH(d, a, b, c, x[8], S32, 0x8771f681);	/* 34 */
  HH(c, d, a, b, x[11], S33, 0x6d9d6122);	/* 35 */
  HH(b, c, d, a, x[14], S34, 0xfde5380c);	/* 36 */
  HH(a, b, c, d, x[1], S31, 0xa4beea44);	/* 37 */
  HH(d, a, b, c, x[4], S32, 0x4bdecfa9);	/* 38 */
  HH(c, d, a, b, x[7], S33, 0xf6bb4b60);	/* 39 */
  HH(b, c, d, a, x[10], S34, 0xbebfbc70);	/* 40 */
  HH(a, b, c, d, x[13], S31, 0x289b7ec6);	/* 41 */
  HH(d, a, b, c, x[0], S32, 0xeaa127fa);	/* 42 */
  HH(c, d, a, b, x[3], S33, 0xd4ef3085);	/* 43 */
  HH(b, c, d, a, x[6], S34, 0x4881d05);		/* 44 */
  HH(a, b, c, d, x[9], S31, 0xd9d4d039);	/* 45 */
  HH(d, a, b, c, x[12], S32, 0xe6db99e5);	/* 46 */
  HH(c, d, a, b, x[15], S33, 0x1fa27cf8);	/* 47 */
  HH(b, c, d, a, x[2], S34, 0xc4ac5665);	/* 48 */

  /* Round 4 */
  II(a, b, c, d, x[0], S41, 0xf4292244);	/* 49 */
  II(d, a, b, c, x[7], S42, 0x432aff97);	/* 50 */
  II(c, d, a, b, x[14], S43, 0xab9423a7);	/* 51 */
  II(b, c, d, a, x[5], S44, 0xfc93a039);	/* 52 */
  II(a, b, c, d, x[12], S41, 0x655b59c3);	/* 53 */
  II(d, a, b, c, x[3], S42, 0x8f0ccc92);	/* 54 */
  II(c, d, a, b, x[10], S43, 0xffeff47d);	/* 55 */
  II(b, c, d, a, x[1], S44, 0x85845dd1);	/* 56 */
  II(a, b, c, d, x[8], S41, 0x6fa87e4f);	/* 57 */
  II(d, a, b, c, x[15], S42, 0xfe2ce6e0);	/* 58 */
  II(c, d, a, b, x[6], S43, 0xa3014314);	/* 59 */
  II(b, c, d, a, x[13], S44, 0x4e0811a1);	/* 60 */
  II(a, b, c, d, x[4], S41, 0xf7537e82);	/* 61 */
  II(d, a, b, c, x[11], S42, 0xbd3af235);	/* 62 */
  II(c, d, a, b, x[2], S43, 0x2ad7d2bb);	/* 63 */
  II(b, c, d, a, x[9], S44, 0xeb86d391);	/* 64 */

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

  memset((char *) x, 0, sizeof(x));
}

void 
md5Encode(unsigned char *output, unsigned long int *input, unsigned int len)
{
  unsigned int i, j;

  for (i = 0, j = 0; j < len; i++, j += 4)
    {
      output[j] = (unsigned char) (input[i] & 0xff);
      output[j + 1] = (unsigned char) ((input[i] >> 8) & 0xff);
      output[j + 2] = (unsigned char) ((input[i] >> 16) & 0xff);
      output[j + 3] = (unsigned char) ((input[i] >> 24) & 0xff);
    }
}

void 
md5Decode(unsigned long int *output, const unsigned char *input, unsigned int len)
{
  unsigned int i, j;

  for (i = 0, j = 0; j < len; i++, j += 4)
    output[i] = ((unsigned long int) input[j]) | (((unsigned long int) input[j + 1]) << 8) |
      (((unsigned long int) input[j + 2]) << 16) | (((unsigned long int) input[j + 3]) << 24);
}
