/*
  * 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 <string.h>

 #include "bswap.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);
 
 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) \
         t = S[i>>4][i&3];\
         a += T[i];\
 \

         if(i<32){\
             if(i<16) a += (d ^ (b&(c^d))) + X[      i &15 ];\
             else     a += (c ^ (d&(c^b))) + X[ (1+5*i)&15 ];\
         }else{\
             if(i<48) a += (b^c^d)         + X[ (5+3*i)&15 ];\
             else     a += (c^(b|~d))      + X[ (  7*i)&15 ];\

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

 static void body(uint32_t ABCD[4], uint32_t X[16]){

     int t;

     int i av_unused;

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

 #if HAVE_BIGENDIAN

     for(i=0; i<16; i++)

         X[i]= av_bswap32(X[i]);

 #endif
 

 #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;
 }
 
 void av_md5_update(AVMD5 *ctx, const uint8_t *src, const int len){

     int i, j;

     j= ctx->len & 63;

     ctx->len += len;
 
     for( i = 0; i < len; i++ ){

         ctx->block[j++] = src[i];
         if( 64 == j ){

             body(ctx->ABCD, (uint32_t*) ctx->block);

             j = 0;

         }
     }
 }
 
 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++)

         ((uint32_t*)dst)[i]= av_le2ne32(ctx->ABCD[3-i]);

 }
 
 void av_md5_sum(uint8_t *dst, const uint8_t *src, const int len){
     AVMD5 ctx[1];
 
     av_md5_init(ctx);
     av_md5_update(ctx, src, len);
     av_md5_final(ctx, dst);
 }
 
 #ifdef TEST
 #include <stdio.h>

 #include <inttypes.h>

 #undef printf

 int main(void){

     uint64_t md5val;
     int i;
     uint8_t in[1000];
 
     for(i=0; i<1000; i++) in[i]= i*i;

     av_md5_sum( (uint8_t*)&md5val, in,  1000); printf("%"PRId64"\n", md5val);
     av_md5_sum( (uint8_t*)&md5val, in,  63); printf("%"PRId64"\n", md5val);
     av_md5_sum( (uint8_t*)&md5val, in,  64); printf("%"PRId64"\n", md5val);
     av_md5_sum( (uint8_t*)&md5val, in,  65); printf("%"PRId64"\n", md5val);

     for(i=0; i<1000; i++) in[i]= i % 127;

     av_md5_sum( (uint8_t*)&md5val, in,  999); printf("%"PRId64"\n", md5val);

 
     return 0;

 }
 #endif