/*
  Copyright (C) 1999, 2000, 2002 Aladdin Enterprises.  All rights reserved.

  This software is provided 'as-is', without any express or implied
  warranty.  In no event will the authors be held liable for any damages
  arising from the use of this software.

  Permission is granted to anyone to use this software for any purpose,
  including commercial applications, and to alter it and redistribute it
  freely, subject to the following restrictions:

  1. The origin of this software must not be misrepresented; you must not
     claim that you wrote the original software. If you use this software
     in a product, an acknowledgement in the product documentation would be
     appreciated but is not required.
  2. Altered source versions must be plainly marked as such, and must not be
     misrepresented as being the original software.
  3. This notice may not be removed or altered from any source distribution.

  L. Peter Deutsch
  ghost@aladdin.com

 */
/* $Id: md5.c,v 1.6 2002/04/13 19:20:28 lpd Exp $ */
/*
  Independent implementation of MD5 (RFC 1321).

  This code implements the MD5 Algorithm defined in RFC 1321, whose
  text is available at
    http://www.ietf.org/rfc/rfc1321.txt
  The code is derived from the text of the RFC, including the test suite
  (section A.5) but excluding the rest of Appendix A.  It does not include
  any code or documentation that is identified in the RFC as being
  copyrighted.

  The original and principal author of md5.c is L. Peter Deutsch
  <ghost@aladdin.com>.  Other authors are noted in the change history
  that follows (in reverse chronological order):

  2002-04-13 lpd Clarified derivation from RFC 1321; now handles byte order
    either statically or dynamically; added missing #include <string.h>
    in library.
  2002-03-11 lpd Corrected argument list for main(), and added int return
    type, in test program and T value program.
  2002-02-21 lpd Added missing #include <stdio.h> in test program.
  2000-07-03 lpd Patched to eliminate warnings about "constant is
    unsigned in ANSI C, signed in traditional"; made test program
    self-checking.
  1999-11-04 lpd Edited comments slightly for automatic TOC extraction.
  1999-10-18 lpd Fixed typo in header comment (ansi2knr rather than md5).
  1999-05-03 lpd Original version.
 */

/*
 * The following MD5 implementation has been modified to use types as
 * specified in libbson.
 */

#include <common-md5-private.h>

#include <string.h>

#undef BYTE_ORDER /* 1 = big-endian, -1 = little-endian, 0 = unknown */
#if BSON_BYTE_ORDER == BSON_BIG_ENDIAN
#define BYTE_ORDER 1
#else
#define BYTE_ORDER -1
#endif

#define T_MASK ((uint32_t)~0)
#define T1 /* 0xd76aa478 */ (T_MASK ^ 0x28955b87)
#define T2 /* 0xe8c7b756 */ (T_MASK ^ 0x173848a9)
#define T3 0x242070db
#define T4 /* 0xc1bdceee */ (T_MASK ^ 0x3e423111)
#define T5 /* 0xf57c0faf */ (T_MASK ^ 0x0a83f050)
#define T6 0x4787c62a
#define T7 /* 0xa8304613 */ (T_MASK ^ 0x57cfb9ec)
#define T8 /* 0xfd469501 */ (T_MASK ^ 0x02b96afe)
#define T9 0x698098d8
#define T10 /* 0x8b44f7af */ (T_MASK ^ 0x74bb0850)
#define T11 /* 0xffff5bb1 */ (T_MASK ^ 0x0000a44e)
#define T12 /* 0x895cd7be */ (T_MASK ^ 0x76a32841)
#define T13 0x6b901122
#define T14 /* 0xfd987193 */ (T_MASK ^ 0x02678e6c)
#define T15 /* 0xa679438e */ (T_MASK ^ 0x5986bc71)
#define T16 0x49b40821
#define T17 /* 0xf61e2562 */ (T_MASK ^ 0x09e1da9d)
#define T18 /* 0xc040b340 */ (T_MASK ^ 0x3fbf4cbf)
#define T19 0x265e5a51
#define T20 /* 0xe9b6c7aa */ (T_MASK ^ 0x16493855)
#define T21 /* 0xd62f105d */ (T_MASK ^ 0x29d0efa2)
#define T22 0x02441453
#define T23 /* 0xd8a1e681 */ (T_MASK ^ 0x275e197e)
#define T24 /* 0xe7d3fbc8 */ (T_MASK ^ 0x182c0437)
#define T25 0x21e1cde6
#define T26 /* 0xc33707d6 */ (T_MASK ^ 0x3cc8f829)
#define T27 /* 0xf4d50d87 */ (T_MASK ^ 0x0b2af278)
#define T28 0x455a14ed
#define T29 /* 0xa9e3e905 */ (T_MASK ^ 0x561c16fa)
#define T30 /* 0xfcefa3f8 */ (T_MASK ^ 0x03105c07)
#define T31 0x676f02d9
#define T32 /* 0x8d2a4c8a */ (T_MASK ^ 0x72d5b375)
#define T33 /* 0xfffa3942 */ (T_MASK ^ 0x0005c6bd)
#define T34 /* 0x8771f681 */ (T_MASK ^ 0x788e097e)
#define T35 0x6d9d6122
#define T36 /* 0xfde5380c */ (T_MASK ^ 0x021ac7f3)
#define T37 /* 0xa4beea44 */ (T_MASK ^ 0x5b4115bb)
#define T38 0x4bdecfa9
#define T39 /* 0xf6bb4b60 */ (T_MASK ^ 0x0944b49f)
#define T40 /* 0xbebfbc70 */ (T_MASK ^ 0x4140438f)
#define T41 0x289b7ec6
#define T42 /* 0xeaa127fa */ (T_MASK ^ 0x155ed805)
#define T43 /* 0xd4ef3085 */ (T_MASK ^ 0x2b10cf7a)
#define T44 0x04881d05
#define T45 /* 0xd9d4d039 */ (T_MASK ^ 0x262b2fc6)
#define T46 /* 0xe6db99e5 */ (T_MASK ^ 0x1924661a)
#define T47 0x1fa27cf8
#define T48 /* 0xc4ac5665 */ (T_MASK ^ 0x3b53a99a)
#define T49 /* 0xf4292244 */ (T_MASK ^ 0x0bd6ddbb)
#define T50 0x432aff97
#define T51 /* 0xab9423a7 */ (T_MASK ^ 0x546bdc58)
#define T52 /* 0xfc93a039 */ (T_MASK ^ 0x036c5fc6)
#define T53 0x655b59c3
#define T54 /* 0x8f0ccc92 */ (T_MASK ^ 0x70f3336d)
#define T55 /* 0xffeff47d */ (T_MASK ^ 0x00100b82)
#define T56 /* 0x85845dd1 */ (T_MASK ^ 0x7a7ba22e)
#define T57 0x6fa87e4f
#define T58 /* 0xfe2ce6e0 */ (T_MASK ^ 0x01d3191f)
#define T59 /* 0xa3014314 */ (T_MASK ^ 0x5cfebceb)
#define T60 0x4e0811a1
#define T61 /* 0xf7537e82 */ (T_MASK ^ 0x08ac817d)
#define T62 /* 0xbd3af235 */ (T_MASK ^ 0x42c50dca)
#define T63 0x2ad7d2bb
#define T64 /* 0xeb86d391 */ (T_MASK ^ 0x14792c6e)


static void
bson_md5_process(bson_md5_t *md5, const uint8_t *data)
{
   uint32_t a = md5->abcd[0];
   uint32_t b = md5->abcd[1];
   uint32_t c = md5->abcd[2];
   uint32_t d = md5->abcd[3];
   uint32_t t;

#if BYTE_ORDER > 0
   /* Define storage only for big-endian CPUs. */
   uint32_t X[16];
#else
   /* Define storage for little-endian or both types of CPUs. */
   uint32_t xbuf[16];
   const uint32_t *X;
#endif

   {
#if BYTE_ORDER == 0
      /*
       * Determine dynamically whether this is a big-endian or
       * little-endian machine, since we can use a more efficient
       * algorithm on the latter.
       */
      static const int w = 1;

      if (*((const uint8_t *)&w)) /* dynamic little-endian */
#endif
#if BYTE_ORDER <= 0 /* little-endian */
      {
         /*
          * On little-endian machines, we can process properly aligned
          * data without copying it.
          */
         if (!(((uintptr_t)data) & 3u)) {
/* data are properly aligned */
#ifdef __clang__
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wcast-align"
#endif
            X = (const uint32_t *)data;
#ifdef __clang__
#pragma clang diagnostic pop
#endif
         } else {
            /* not aligned */
            memcpy(xbuf, data, sizeof(xbuf));
            X = xbuf;
         }
      }
#endif
#if BYTE_ORDER == 0
      else /* dynamic big-endian */
#endif
#if BYTE_ORDER >= 0 /* big-endian */
      {
         /*
          * On big-endian machines, we must arrange the bytes in the
          * right order.
          */
         const uint8_t *xp = data;
         int i;

#if BYTE_ORDER == 0
         X = xbuf; /* (dynamic only) */
#else
#define xbuf X /* (static only) */
#endif
         for (i = 0; i < 16; ++i, xp += 4)
            xbuf[i] = xp[0] + (xp[1] << 8) + (xp[2] << 16) + (xp[3] << 24);
      }
#endif
   }

#define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32 - (n))))

/* Round 1. */
/* Let [abcd k s i] denote the operation
   a = b + ((a + F(b,c,d) + X[k] + T[i]) <<< s). */
#define F(x, y, z) (((x) & (y)) | (~(x) & (z)))
#define SET(a, b, c, d, k, s, Ti)  \
   t = a + F(b, c, d) + X[k] + Ti; \
   a = ROTATE_LEFT(t, s) + b
   /* Do the following 16 operations. */
   SET(a, b, c, d, 0, 7, T1);
   SET(d, a, b, c, 1, 12, T2);
   SET(c, d, a, b, 2, 17, T3);
   SET(b, c, d, a, 3, 22, T4);
   SET(a, b, c, d, 4, 7, T5);
   SET(d, a, b, c, 5, 12, T6);
   SET(c, d, a, b, 6, 17, T7);
   SET(b, c, d, a, 7, 22, T8);
   SET(a, b, c, d, 8, 7, T9);
   SET(d, a, b, c, 9, 12, T10);
   SET(c, d, a, b, 10, 17, T11);
   SET(b, c, d, a, 11, 22, T12);
   SET(a, b, c, d, 12, 7, T13);
   SET(d, a, b, c, 13, 12, T14);
   SET(c, d, a, b, 14, 17, T15);
   SET(b, c, d, a, 15, 22, T16);
#undef SET

/* Round 2. */
/* Let [abcd k s i] denote the operation
     a = b + ((a + G(b,c,d) + X[k] + T[i]) <<< s). */
#define G(x, y, z) (((x) & (z)) | ((y) & ~(z)))
#define SET(a, b, c, d, k, s, Ti)  \
   t = a + G(b, c, d) + X[k] + Ti; \
   a = ROTATE_LEFT(t, s) + b
   /* Do the following 16 operations. */
   SET(a, b, c, d, 1, 5, T17);
   SET(d, a, b, c, 6, 9, T18);
   SET(c, d, a, b, 11, 14, T19);
   SET(b, c, d, a, 0, 20, T20);
   SET(a, b, c, d, 5, 5, T21);
   SET(d, a, b, c, 10, 9, T22);
   SET(c, d, a, b, 15, 14, T23);
   SET(b, c, d, a, 4, 20, T24);
   SET(a, b, c, d, 9, 5, T25);
   SET(d, a, b, c, 14, 9, T26);
   SET(c, d, a, b, 3, 14, T27);
   SET(b, c, d, a, 8, 20, T28);
   SET(a, b, c, d, 13, 5, T29);
   SET(d, a, b, c, 2, 9, T30);
   SET(c, d, a, b, 7, 14, T31);
   SET(b, c, d, a, 12, 20, T32);
#undef SET

/* Round 3. */
/* Let [abcd k s t] denote the operation
     a = b + ((a + H(b,c,d) + X[k] + T[i]) <<< s). */
#define H(x, y, z) ((x) ^ (y) ^ (z))
#define SET(a, b, c, d, k, s, Ti)  \
   t = a + H(b, c, d) + X[k] + Ti; \
   a = ROTATE_LEFT(t, s) + b
   /* Do the following 16 operations. */
   SET(a, b, c, d, 5, 4, T33);
   SET(d, a, b, c, 8, 11, T34);
   SET(c, d, a, b, 11, 16, T35);
   SET(b, c, d, a, 14, 23, T36);
   SET(a, b, c, d, 1, 4, T37);
   SET(d, a, b, c, 4, 11, T38);
   SET(c, d, a, b, 7, 16, T39);
   SET(b, c, d, a, 10, 23, T40);
   SET(a, b, c, d, 13, 4, T41);
   SET(d, a, b, c, 0, 11, T42);
   SET(c, d, a, b, 3, 16, T43);
   SET(b, c, d, a, 6, 23, T44);
   SET(a, b, c, d, 9, 4, T45);
   SET(d, a, b, c, 12, 11, T46);
   SET(c, d, a, b, 15, 16, T47);
   SET(b, c, d, a, 2, 23, T48);
#undef SET

/* Round 4. */
/* Let [abcd k s t] denote the operation
     a = b + ((a + I(b,c,d) + X[k] + T[i]) <<< s). */
#define I(x, y, z) ((y) ^ ((x) | ~(z)))
#define SET(a, b, c, d, k, s, Ti)  \
   t = a + I(b, c, d) + X[k] + Ti; \
   a = ROTATE_LEFT(t, s) + b
   /* Do the following 16 operations. */
   SET(a, b, c, d, 0, 6, T49);
   SET(d, a, b, c, 7, 10, T50);
   SET(c, d, a, b, 14, 15, T51);
   SET(b, c, d, a, 5, 21, T52);
   SET(a, b, c, d, 12, 6, T53);
   SET(d, a, b, c, 3, 10, T54);
   SET(c, d, a, b, 10, 15, T55);
   SET(b, c, d, a, 1, 21, T56);
   SET(a, b, c, d, 8, 6, T57);
   SET(d, a, b, c, 15, 10, T58);
   SET(c, d, a, b, 6, 15, T59);
   SET(b, c, d, a, 13, 21, T60);
   SET(a, b, c, d, 4, 6, T61);
   SET(d, a, b, c, 11, 10, T62);
   SET(c, d, a, b, 2, 15, T63);
   SET(b, c, d, a, 9, 21, T64);
#undef SET

   /* Then perform the following additions. (That is increment each
      of the four registers by the value it had before this block
      was started.) */
   md5->abcd[0] += a;
   md5->abcd[1] += b;
   md5->abcd[2] += c;
   md5->abcd[3] += d;
}

void
mcommon_md5_init(bson_md5_t *pms)
{
   pms->count[0] = pms->count[1] = 0;
   pms->abcd[0] = 0x67452301;
   pms->abcd[1] = /*0xefcdab89*/ T_MASK ^ 0x10325476;
   pms->abcd[2] = /*0x98badcfe*/ T_MASK ^ 0x67452301;
   pms->abcd[3] = 0x10325476;
}

void
mcommon_md5_append(bson_md5_t *pms, const uint8_t *data, uint32_t nbytes)
{
   const uint8_t *p = data;
   uint32_t left = nbytes;
   uint8_t offset = (pms->count[0] >> 3) & 63;
   uint32_t nbits = (uint32_t)(nbytes << 3);

   if (nbytes <= 0)
      return;

   /* Update the message length. */
   pms->count[1] += nbytes >> 29;
   pms->count[0] += nbits;
   if (pms->count[0] < nbits)
      pms->count[1]++;

   /* Process an initial partial block. */
   if (offset) {
      uint32_t copy = (offset + nbytes > 64u ? 64u - offset : nbytes);

      memcpy(pms->buf + offset, p, copy);
      if (offset + copy < 64)
         return;
      p += copy;
      left -= copy;
      bson_md5_process(pms, pms->buf);
   }

   /* Process full blocks. */
   for (; left >= 64; p += 64, left -= 64)
      bson_md5_process(pms, p);

   /* Process a final partial block. */
   if (left)
      memcpy(pms->buf, p, left);
}


void
mcommon_md5_finish(bson_md5_t *pms, uint8_t digest[16])
{
   static const uint8_t pad[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};
   uint8_t data[8];
   int i;

   /* Save the length before padding. */
   for (i = 0; i < 8; ++i)
      data[i] = (uint8_t)(pms->count[i >> 2] >> ((i & 3) << 3));
   /* Pad to 56 bytes mod 64. */
   mcommon_md5_append(pms, pad, ((55 - (pms->count[0] >> 3)) & 63) + 1);
   /* Append the length. */
   mcommon_md5_append(pms, data, sizeof(data));
   for (i = 0; i < 16; ++i)
      digest[i] = (uint8_t)(pms->abcd[i >> 2] >> ((i & 3) << 3));
}
