/*
   Resumen MD5
   Autor: José David Guillén

   Basado en el fuente PASCAL de Dimka Maslov                        }

   Derived from the RSA Data Security, Inc.
   MD5 Message-Digest Algorithm described in RFC 1321
   http://www.faqs.org/rfcs/rfc1321.html
*/

#include "TMD5.hpp"

#include <mem.h>


/* Constants for MD5Transform routine.
 */

#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) + (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); \
  }


//------------------------------------------------------------------------------
void __fastcall TMD5::MD5Encode(unsigned char *Output, UINT4 *Input, const unsigned int Len)
{
 UINT4 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 __fastcall TMD5::MD5Decode(UINT4 *Output, const unsigned char *Input, const UINT4 Len)
{
 UINT4 i,j;

 for (i = 0, j = 0; j < Len; i++, j += 4)
   Output[i] = ((UINT4)(Input[j])) | ((UINT4)(Input[j+1]) << 8) |
       ((UINT4)(Input[j+2]) << 16) | ((UINT4)(Input[j+3]) << 24);
}
//------------------------------------------------------------------------------
void __fastcall TMD5::MD5_memcpy(PByteArray Output, const PByteArray Input, UINT4 Len)
{
 memcpy( Output, Input, Len );
}
//------------------------------------------------------------------------------
void __fastcall TMD5::MD5_memset(PByteArray Output, int Value, UINT4 Len)
{
 setmem( Output, Len, (Byte)Value );
/*
 for ( ; Len>0; Len-- )
  Output[Len-1] = (Byte)Value;
*/
}
//------------------------------------------------------------------------------
void __fastcall TMD5::MD5Transform(UINT4 State[4], const unsigned char Buffer[64])
{
 UINT4 a,b,c,d;
 UINT4 x[16];

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

 MD5Decode( x, Buffer, 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;

 MD5_memset( (PByteArray)x, 0, sizeof(x) );
}
//------------------------------------------------------------------------------
void __fastcall TMD5::MD5Init(TMD5Context *Context)
{
 setmem( (void *)Context, sizeof(TMD5Context), 0);

 Context->state[0] = 0x67452301;
 Context->state[1] = 0xefcdab89;
 Context->state[2] = 0x98badcfe;
 Context->state[3] = 0x10325476;
}
//------------------------------------------------------------------------------
void __fastcall TMD5::MD5Update(TMD5Context *Context, const unsigned char *Input, const unsigned int InputLen)
{
  unsigned int i, index, partLen;

  /* Compute number of bytes mod 64 */
  index = (unsigned int)((Context->count[0] >> 3) & 0x3F);

  /* Update number of bits */
  if ((Context->count[0] += ((UINT4)InputLen << 3)) < ((UINT4)InputLen << 3))
         Context->count[1]++;
  Context->count[1] += ((UINT4)InputLen >> 29);

  partLen = 64 - index;

  /* Transform as many times as possible.*/
  if (InputLen >= partLen)
  {
        MD5_memcpy((PByteArray)&Context->buffer[index], (PByteArray)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;

  /* Buffer remaining input */
  MD5_memcpy((PByteArray)&Context->buffer[index], (PByteArray)&Input[i], InputLen-i);
}
//------------------------------------------------------------------------------
void __fastcall TMD5::MD5Final(unsigned char Digest[16], TMD5Context *Context)
{
 unsigned char bits[8];
 UINT4 index, padLen;

 MD5Encode( bits, Context->count, 8);

 index = (UINT4)( ( 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);

 MD5_memset((PByteArray)Context, 0, sizeof(*Context));
}
//------------------------------------------------------------------------------
AnsiString __fastcall TMD5::MD5DigestToStr(const TMD5Digest &Digest)
{
 AnsiString Result;
 int i;

 Result="";
 for ( i=0; i<=15; i++ )
  Result = Result + IntToHex(Digest.v[i], 2);

 return Result;
}
//------------------------------------------------------------------------------
TMD5Digest __fastcall TMD5::MD5String(const AnsiString S)
{
 return MD5Buffer((PChar)S.c_str(), S.Length());
}
//------------------------------------------------------------------------------
TMD5Digest __fastcall TMD5::MD5File(const AnsiString FileName)
{
 TMD5Digest Result;
 TFileStream *F;

 F = new TFileStream(FileName, fmOpenRead);
 try {
  Result=MD5Stream(F);
 } __finally {
  delete F;
 }
 return Result;
}
//------------------------------------------------------------------------------
/* Classes::*/
TMD5Digest __fastcall TMD5::MD5Stream(const Classes::TStream *Stream)
{
 TMD5Context Context;
 TMD5Digest Result;
 Byte Buffer[4096];
 int Size;
 int ReadBytes;
 int TotalBytes;
 int SavePos;

 MD5Init(&Context);
 Size=Stream->Size;
 SavePos=Stream->Position;
 TotalBytes=0;
 try {
  Stream->Seek(0, soFromBeginning);
  do {
   ReadBytes=Stream->Read(Buffer, sizeof(Buffer));
   TotalBytes+=ReadBytes;
   MD5Update(&Context, Buffer, ReadBytes);
  } while( !( (ReadBytes == 0) || (TotalBytes == Size) ) );
 } __finally {
  Stream->Seek(SavePos, soFromBeginning);
 }
 MD5Final((unsigned char *)&Result, &Context);
 return Result;
}
//------------------------------------------------------------------------------
TMD5Digest __fastcall TMD5::MD5Buffer(const void *Buffer, int Size)
{
 TMD5Context Context;
 TMD5Digest Result;

 MD5Init(&Context);
 MD5Update(&Context, (unsigned char *)Buffer, Size);
 MD5Final((unsigned char *)&Result, &Context);

 return Result;
}
//------------------------------------------------------------------------------
bool __fastcall TMD5::MD5DigestCompare(const TMD5Digest &Digest1, const TMD5Digest &Digest2)
{
 bool Result;

 Result=true;
 if (Digest1.A != Digest2.A) Result=false;
 if (Digest1.B != Digest2.B) Result=false;
 if (Digest1.C != Digest2.C) Result=false;
 if (Digest1.D != Digest2.D) Result=false;

 return Result;
}
//------------------------------------------------------------------------------