/*
  * Copyright (C) 2006 Michael Niedermayer (michaelni@gmx.at)
  * Copyright (C) 2003-2005 by Christopher R. Hertel (crh@ubiqx.mn.org)

  *

  * References:
  *  IETF RFC 1321: The MD5 Message-Digest Algorithm
  *       Ron Rivest. IETF, April, 1992
  *
  * based on http://ubiqx.org/libcifs/source/Auth/MD5.c
  *          from Christopher R. Hertel (crh@ubiqx.mn.org)

  * Simplified, cleaned and IMO redundant comments removed by Michael.

  *
  * If you use gcc, then version 4.1 or later and -fomit-frame-pointer is
  * strongly recommended.
  *

  * This file is part of FFmpeg.
  *
  * FFmpeg 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.

  *

  * FFmpeg 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 FFmpeg; if not, write to the Free Software

  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

  */
 

 #include <stdint.h>

 #include "bswap.h"

 #include "intreadwrite.h"

 #include "mem.h"

 #include "md5.h"

 typedef struct AVMD5 {

     uint64_t len;

     uint8_t  block[64];
     uint32_t ABCD[4];
 } AVMD5;
 

 const int av_md5_size = sizeof(AVMD5);

 
 struct AVMD5 *av_md5_alloc(void)
 {
     return av_mallocz(sizeof(struct AVMD5));
 }

 
 static const uint8_t S[4][4] = {

     { 7, 12, 17, 22 },  /* round 1 */
     { 5,  9, 14, 20 },  /* round 2 */
     { 4, 11, 16, 23 },  /* round 3 */
     { 6, 10, 15, 21 }   /* round 4 */

 };
 

 static const uint32_t T[64] = { // T[i]= fabs(sin(i+1)<<32)

     0xd76aa478, 0xe8c7b756, 0x242070db, 0xc1bdceee,   /* round 1 */

     0xf57c0faf, 0x4787c62a, 0xa8304613, 0xfd469501,
     0x698098d8, 0x8b44f7af, 0xffff5bb1, 0x895cd7be,
     0x6b901122, 0xfd987193, 0xa679438e, 0x49b40821,
 

     0xf61e2562, 0xc040b340, 0x265e5a51, 0xe9b6c7aa,   /* round 2 */

     0xd62f105d, 0x02441453, 0xd8a1e681, 0xe7d3fbc8,
     0x21e1cde6, 0xc33707d6, 0xf4d50d87, 0x455a14ed,
     0xa9e3e905, 0xfcefa3f8, 0x676f02d9, 0x8d2a4c8a,
 

     0xfffa3942, 0x8771f681, 0x6d9d6122, 0xfde5380c,   /* round 3 */

     0xa4beea44, 0x4bdecfa9, 0xf6bb4b60, 0xbebfbc70,
     0x289b7ec6, 0xeaa127fa, 0xd4ef3085, 0x04881d05,
     0xd9d4d039, 0xe6db99e5, 0x1fa27cf8, 0xc4ac5665,
 

     0xf4292244, 0x432aff97, 0xab9423a7, 0xfc93a039,   /* round 4 */

     0x655b59c3, 0x8f0ccc92, 0xffeff47d, 0x85845dd1,
     0x6fa87e4f, 0xfe2ce6e0, 0xa3014314, 0x4e0811a1,
     0xf7537e82, 0xbd3af235, 0x2ad7d2bb, 0xeb86d391,
 };
 

 #define CORE(i, a, b, c, d)                                             \
     do {                                                                \
         t  = S[i >> 4][i & 3];                                          \

         a += T[i];                                                      \
                                                                         \
         if (i < 32) {                                                   \

             if (i < 16)                                                 \

                 a += (d ^ (b & (c ^ d)))  + AV_RL32(X+(       i  & 15));\

             else                                                        \

                 a += ((d & b) | (~d & c)) + AV_RL32(X+((1 + 5*i) & 15));\

         } else {                                                        \

             if (i < 48)                                                 \

                 a += (b ^ c ^ d)          + AV_RL32(X+((5 + 3*i) & 15));\

             else                                                        \

                 a += (c ^ (b | ~d))       + AV_RL32(X+((    7*i) & 15));\

         }                                                               \
         a = b + (a << t | a >> (32 - t));                               \
     } while (0)
 

 static void body(uint32_t ABCD[4], const uint8_t *src, int nblocks)

 {

     int i av_unused;

     int n;

     const uint32_t *X;
     uint32_t a, b, c, d, t;

 
     for (n = 0; n < nblocks; n++) {
         a = ABCD[3];
         b = ABCD[2];
         c = ABCD[1];
         d = ABCD[0];
 

         X = (const uint32_t *)src + n * 16;

 #if CONFIG_SMALL

         for (i = 0; i < 64; i++) {
             CORE(i, a, b, c, d);
             t = d;
             d = c;
             c = b;
             b = a;
             a = t;
         }

 #else

 #define CORE2(i)                                                        \

         CORE(i, a, b, c, d); CORE((i + 1), d, a, b, c);                 \
         CORE((i + 2), c, d, a, b); CORE((i + 3), b, c, d, a)

 #define CORE4(i) CORE2(i); CORE2((i + 4)); CORE2((i + 8)); CORE2((i + 12))

         CORE4(0);
         CORE4(16);
         CORE4(32);
         CORE4(48);

 #endif
 

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

     }

 }
 

 void av_md5_init(AVMD5 *ctx)
 {
     ctx->len     = 0;

 
     ctx->ABCD[0] = 0x10325476;
     ctx->ABCD[1] = 0x98badcfe;
     ctx->ABCD[2] = 0xefcdab89;
     ctx->ABCD[3] = 0x67452301;
 }
 

 #if FF_API_CRYPTO_SIZE_T

 void av_md5_update(AVMD5 *ctx, const uint8_t *src, int len)

 #else
 void av_md5_update(AVMD5 *ctx, const uint8_t *src, size_t len)
 #endif

 {

     const uint8_t *end;
     int j;

     j         = ctx->len & 63;

     ctx->len += len;
 

     if (j) {
         int cnt = FFMIN(len, 64 - j);
         memcpy(ctx->block + j, src, cnt);
         src += cnt;
         len -= cnt;
         if (j + cnt < 64)
             return;

         body(ctx->ABCD, ctx->block, 1);

     }
 
     end = src + (len & ~63);

     if (!HAVE_FAST_UNALIGNED && ((intptr_t)src & 3)) {

        while (src < end) {
            memcpy(ctx->block, src, 64);

            body(ctx->ABCD, ctx->block, 1);

            src += 64;
         }
     } else {

         int nblocks = len / 64;

         body(ctx->ABCD, src, nblocks);

         src = end;

     }

     len &= 63;
     if (len > 0)
         memcpy(ctx->block, src, len);

 }
 

 void av_md5_final(AVMD5 *ctx, uint8_t *dst)
 {

     int i;

     uint64_t finalcount = av_le2ne64(ctx->len << 3);

     av_md5_update(ctx, "\200", 1);

     while ((ctx->len & 63) != 56)

         av_md5_update(ctx, "", 1);

     av_md5_update(ctx, (uint8_t *) &finalcount, 8);

     for (i = 0; i < 4; i++)

         AV_WL32(dst + 4 * i, ctx->ABCD[3 - i]);

 }
 

 #if FF_API_CRYPTO_SIZE_T

 void av_md5_sum(uint8_t *dst, const uint8_t *src, const int len)

 #else
 void av_md5_sum(uint8_t *dst, const uint8_t *src, size_t len)
 #endif

 {
     AVMD5 ctx;

     av_md5_init(&ctx);
     av_md5_update(&ctx, src, len);
     av_md5_final(&ctx, dst);

 }