/*
 ***********************************************************************
 ** md5.c -- the source code for MD5 routines                         **
 ** RSA Data Security, Inc. MD5 Message-Digest Algorithm              **
 ** Created: 2/17/90 RLR                                              **
 ** Revised: 1/91 SRD,AJ,BSK,JT Reference C Version                   **
 ***********************************************************************
 */

/*
 * Edited 7 May 93 by CP to change the interface to match that
 * of the MD5 routines in RSAREF.  Due to this alteration, this
 * code is "derived from the RSA Data Security, Inc. MD5 Message-
 * Digest Algorithm".  (See below.)
 */

/*
 ***********************************************************************
 ** Copyright (C) 1990, RSA Data Security, Inc. 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 "md5.h"

/*
 ***********************************************************************
 **  Message-digest routines:                                         **
 **  To form the message digest for a message M                       **
 **    (1) Initialize a context buffer mdContext using MD5Init        **
 **    (2) Call MD5Update on mdContext and M                          **
 **    (3) Call MD5Final on mdContext                                 **
 **  The message digest is now in the bugffer passed to MD5Final      **
 ***********************************************************************
 */

static unsigned char PADDING[64] = {
  0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
};

/* 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) + (UINT4)(ac); \
   (a) = ROTATE_LEFT ((a), (s)); \
   (a) += (b); \
  }
#define GG(a, b, c, d, x, s, ac) \
  {(a) += G ((b), (c), (d)) + (x) + (UINT4)(ac); \
   (a) = ROTATE_LEFT ((a), (s)); \
   (a) += (b); \
  }
#define HH(a, b, c, d, x, s, ac) \
  {(a) += H ((b), (c), (d)) + (x) + (UINT4)(ac); \
   (a) = ROTATE_LEFT ((a), (s)); \
   (a) += (b); \
  }
#define II(a, b, c, d, x, s, ac) \
  {(a) += I ((b), (c), (d)) + (x) + (UINT4)(ac); \
   (a) = ROTATE_LEFT ((a), (s)); \
   (a) += (b); \
  }

/* The routine MD5Init initializes the message-digest context
   mdContext. All fields are set to zero.
 */
void MD5Init (mdContext)
MD5_CTX *mdContext;
{
  mdContext->i[0] = mdContext->i[1] = (UINT4)0;

  /* Load magic initialization constants.
   */
  mdContext->buf[0] = (UINT4)0x67452301L;
  mdContext->buf[1] = (UINT4)0xefcdab89L;
  mdContext->buf[2] = (UINT4)0x98badcfeL;
  mdContext->buf[3] = (UINT4)0x10325476L;
}

/* The routine MD5Update updates the message-digest context to
   account for the presence of each of the characters inBuf[0..inLen-1]
   in the message whose digest is being computed.
 */
void MD5Update (mdContext, inBuf, inLen)
     register MD5_CTX *mdContext;
     unsigned char *inBuf;
     Tcl_Size inLen;
{
  register int i, ii;
  int mdi;
  UINT4 in[16];

  /* compute number of bytes mod 64 */
  mdi = (int)((mdContext->i[0] >> 3) & 0x3F);

  /* update number of bits */
  if ((mdContext->i[0] + ((UINT4)inLen << 3)) < mdContext->i[0])
    mdContext->i[1]++;
  mdContext->i[0] += ((UINT4)inLen << 3);
  mdContext->i[1] += ((UINT4)inLen >> 29);

  while (inLen--) {
    /* add new character to buffer, increment mdi */
    mdContext->in[mdi++] = *inBuf++;

    /* transform if necessary */
    if (mdi == 0x40) {
      for (i = 0, ii = 0; i < 16; i++, ii += 4)
        in[i] = (((UINT4)mdContext->in[ii+3]) << 24) |
                (((UINT4)mdContext->in[ii+2]) << 16) |
                (((UINT4)mdContext->in[ii+1]) << 8) |
                ((UINT4)mdContext->in[ii]);
      Transform (mdContext->buf, in);
      mdi = 0;
    }
  }
}

/* The routine MD5Final terminates the message-digest computation and
   ends with the desired message digest in mdContext->digest[0...15].
 */
void MD5Final (digest, mdContext)
unsigned char digest[16]; MD5_CTX *mdContext;
{
  UINT4 in[16];
  int mdi;
  unsigned int i, ii;
  unsigned int padLen;

  /* save number of bits */
  in[14] = mdContext->i[0];
  in[15] = mdContext->i[1];

  /* compute number of bytes mod 64 */
  mdi = (int)((mdContext->i[0] >> 3) & 0x3F);

  /* pad out to 56 mod 64 */
  padLen = (mdi < 56) ? (56 - mdi) : (120 - mdi);
  MD5Update (mdContext, PADDING, padLen);

  /* append length in bits and transform */
  for (i = 0, ii = 0; i < 14; i++, ii += 4)
    in[i] = (((UINT4)mdContext->in[ii+3]) << 24) |
            (((UINT4)mdContext->in[ii+2]) << 16) |
            (((UINT4)mdContext->in[ii+1]) << 8) |
            ((UINT4)mdContext->in[ii]);
  Transform (mdContext->buf, in);

  /* store buffer in digest */
  for (i = 0, ii = 0; i < 4; i++, ii += 4) {
    digest[ii]   = (unsigned char) (mdContext->buf[i]        & 0xFF);
    digest[ii+1] = (unsigned char)((mdContext->buf[i] >> 8)  & 0xFF);
    digest[ii+2] = (unsigned char)((mdContext->buf[i] >> 16) & 0xFF);
    digest[ii+3] = (unsigned char)((mdContext->buf[i] >> 24) & 0xFF);
  }
}

/* Basic MD5 step. Transforms buf based on in.  Note that if the Mysterious
   Constants are arranged backwards in little-endian order and decrypted with
   the DES they produce OCCULT MESSAGES!
 */
void Transform(buf, in)
register UINT4 *buf;
register UINT4 *in;
{
  register UINT4 a = buf[0], b = buf[1], c = buf[2], d = buf[3];

  /* Round 1 */
#define S11 7
#define S12 12
#define S13 17
#define S14 22
  FF ( a, b, c, d, in[ 0], S11, 0xD76AA478L); /* 1 */
  FF ( d, a, b, c, in[ 1], S12, 0xE8C7B756L); /* 2 */
  FF ( c, d, a, b, in[ 2], S13, 0x242070DBL); /* 3 */
  FF ( b, c, d, a, in[ 3], S14, 0xC1BDCEEEL); /* 4 */
  FF ( a, b, c, d, in[ 4], S11, 0xF57C0FAFL); /* 5 */
  FF ( d, a, b, c, in[ 5], S12, 0x4787C62AL); /* 6 */
  FF ( c, d, a, b, in[ 6], S13, 0xA8304613L); /* 7 */
  FF ( b, c, d, a, in[ 7], S14, 0xFD469501L); /* 8 */
  FF ( a, b, c, d, in[ 8], S11, 0x698098D8L); /* 9 */
  FF ( d, a, b, c, in[ 9], S12, 0x8B44F7AFL); /* 10 */
  FF ( c, d, a, b, in[10], S13, 0xFFFF5BB1L); /* 11 */
  FF ( b, c, d, a, in[11], S14, 0x895CD7BEL); /* 12 */
  FF ( a, b, c, d, in[12], S11, 0x6B901122L); /* 13 */
  FF ( d, a, b, c, in[13], S12, 0xFD987193L); /* 14 */
  FF ( c, d, a, b, in[14], S13, 0xA679438EL); /* 15 */
  FF ( b, c, d, a, in[15], S14, 0x49B40821L); /* 16 */

  /* Round 2 */
#define S21 5
#define S22 9
#define S23 14
#define S24 20
  GG ( a, b, c, d, in[ 1], S21, 0xF61E2562L); /* 17 */
  GG ( d, a, b, c, in[ 6], S22, 0xC040B340L); /* 18 */
  GG ( c, d, a, b, in[11], S23, 0x265E5A51L); /* 19 */
  GG ( b, c, d, a, in[ 0], S24, 0xE9B6C7AAL); /* 20 */
  GG ( a, b, c, d, in[ 5], S21, 0xD62F105DL); /* 21 */
  GG ( d, a, b, c, in[10], S22, 0x02441453L); /* 22 */
  GG ( c, d, a, b, in[15], S23, 0xD8A1E681L); /* 23 */
  GG ( b, c, d, a, in[ 4], S24, 0xE7D3FBC8L); /* 24 */
  GG ( a, b, c, d, in[ 9], S21, 0x21E1CDE6L); /* 25 */
  GG ( d, a, b, c, in[14], S22, 0xC33707D6L); /* 26 */
  GG ( c, d, a, b, in[ 3], S23, 0xF4D50D87L); /* 27 */
  GG ( b, c, d, a, in[ 8], S24, 0x455A14EDL); /* 28 */
  GG ( a, b, c, d, in[13], S21, 0xA9E3E905L); /* 29 */
  GG ( d, a, b, c, in[ 2], S22, 0xFCEFA3F8L); /* 30 */
  GG ( c, d, a, b, in[ 7], S23, 0x676F02D9L); /* 31 */
  GG ( b, c, d, a, in[12], S24, 0x8D2A4C8AL); /* 32 */

  /* Round 3 */
#define S31 4
#define S32 11
#define S33 16
#define S34 23
  HH ( a, b, c, d, in[ 5], S31, 0xFFFA3942L); /* 33 */
  HH ( d, a, b, c, in[ 8], S32, 0x8771F681L); /* 34 */
  HH ( c, d, a, b, in[11], S33, 0x6D9D6122L); /* 35 */
  HH ( b, c, d, a, in[14], S34, 0xFDE5380CL); /* 36 */
  HH ( a, b, c, d, in[ 1], S31, 0xA4BEEA44L); /* 37 */
  HH ( d, a, b, c, in[ 4], S32, 0x4BDECFA9L); /* 38 */
  HH ( c, d, a, b, in[ 7], S33, 0xF6BB4B60L); /* 39 */
  HH ( b, c, d, a, in[10], S34, 0xBEBFBC70L); /* 40 */
  HH ( a, b, c, d, in[13], S31, 0x289B7EC6L); /* 41 */
  HH ( d, a, b, c, in[ 0], S32, 0xEAA127FAL); /* 42 */
  HH ( c, d, a, b, in[ 3], S33, 0xD4EF3085L); /* 43 */
  HH ( b, c, d, a, in[ 6], S34, 0x04881D05L); /* 44 */
  HH ( a, b, c, d, in[ 9], S31, 0xD9D4D039L); /* 45 */
  HH ( d, a, b, c, in[12], S32, 0xE6DB99E5L); /* 46 */
  HH ( c, d, a, b, in[15], S33, 0x1FA27CF8L); /* 47 */
  HH ( b, c, d, a, in[ 2], S34, 0xC4AC5665L); /* 48 */

  /* Round 4 */
#define S41 6
#define S42 10
#define S43 15
#define S44 21
  II ( a, b, c, d, in[ 0], S41, 0xF4292244L); /* 49 */
  II ( d, a, b, c, in[ 7], S42, 0x432AFF97L); /* 50 */
  II ( c, d, a, b, in[14], S43, 0xAB9423A7L); /* 51 */
  II ( b, c, d, a, in[ 5], S44, 0xFC93A039L); /* 52 */
  II ( a, b, c, d, in[12], S41, 0x655B59C3L); /* 53 */
  II ( d, a, b, c, in[ 3], S42, 0x8F0CCC92L); /* 54 */
  II ( c, d, a, b, in[10], S43, 0xFFEFF47DL); /* 55 */
  II ( b, c, d, a, in[ 1], S44, 0x85845DD1L); /* 56 */
  II ( a, b, c, d, in[ 8], S41, 0x6FA87E4FL); /* 57 */
  II ( d, a, b, c, in[15], S42, 0xFE2CE6E0L); /* 58 */
  II ( c, d, a, b, in[ 6], S43, 0xA3014314L); /* 59 */
  II ( b, c, d, a, in[13], S44, 0x4E0811A1L); /* 60 */
  II ( a, b, c, d, in[ 4], S41, 0xF7537E82L); /* 61 */
  II ( d, a, b, c, in[11], S42, 0xBD3AF235L); /* 62 */
  II ( c, d, a, b, in[ 2], S43, 0x2AD7D2BBL); /* 63 */
  II ( b, c, d, a, in[ 9], S44, 0xEB86D391L); /* 64 */

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

