/* MD5C.CPP - RSA Data Security, Inc., MD5 message-digest algorithm
 */

#include "stdafx.h"
//#include <stdlib.h>
//#include "md5_global.h"
//#include "md5.h"

typedef struct 
{
  ui32 state[4]; /* state (ABCD) */
  ui32 count[2]; /* number of bits, modulo 2^64 (lsb first) */
  unsigned char buffer[64]; /* input buffer */
} MD5_CTX;

MD5_CTX context;

/* 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

void MD5Transform /*PROTO_LIST*/ (ui32[4], unsigned char[64]);
static void Encode /*PROTO_LIST*/(unsigned char *,
                               ui32 *,
                               unsigned int);
static void Decode /*PROTO_LIST*/ (ui32 *,
                                unsigned char *,
                                unsigned int);
//static void MD5_memcpy /*PROTO_LIST*/ (i8 *, i8 *, unsigned int);
//static void MD5_memset /*PROTO_LIST*/ (i8 *, int, unsigned int);

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, 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, 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) + (ui32)(ac); (a) = ROTATE_LEFT ((a), (s)); (a) += (b); }

#define GG(a,b,c,d,x,s,ac) { (a) += G ((b), (c), (d)) + (x) + (ui32)(ac); (a) = ROTATE_LEFT ((a), (s)); (a) += (b); }

#define HH(a,b,c,d,x,s,ac) { (a) += H ((b), (c), (d)) + (x) + (ui32)(ac); (a) = ROTATE_LEFT ((a), (s)); (a) += (b); }

#define II(a,b,c,d,x,s,ac) { (a) += I ((b), (c), (d)) + (x) + (ui32)(ac); (a) = ROTATE_LEFT ((a), (s)); (a) += (b); }

/* MD5 initialization.  Begins an MD5 operation, writing a new context.
 */
void MD5Init (MD5_CTX *ctxt)
{
  ctxt->count[0] = ctxt->count[1] = 0;
  /* Load magic initialization constants.
   */
  ctxt->state[0] = 0x67452301;
  ctxt->state[1] = 0xefcdab89;
  ctxt->state[2] = 0x98badcfe;
  ctxt->state[3] = 0x10325476;
}

void MD5Init(void)
{
  MD5Init(&context);
}

/* MD5 block update operation.  COntinues an MD5 message-digest
   operation, processing another message block, and updating the
   context.
 */
void MD5Update(MD5_CTX *ctxt,
               ui8 *input,
               ui32 inputLen)
{
  ui32 i, index, partLen;
  /* Compute number of bytes mod 64 */
  index = (ui32)((ctxt->count[0] >> 3) & 0x3f);
  /* Update number of bits */
  if ((ctxt->count[0] += ((ui32)inputLen << 3))
       < ((ui32)inputLen << 3)) 
    ctxt->count[1]++;
  ctxt->count[1] += ((ui32)inputLen >> 29);
  partLen = 64 - index;
  /* Transform as many times as possible */
  if (inputLen >= partLen) 
  {
    memcpy((i8 *)&ctxt->buffer[index],
              (i8 *)input,
              partLen);
    MD5Transform(ctxt->state, ctxt->buffer);
    for (i=partLen; i+63 < inputLen; i += 64)
         MD5Transform(ctxt->state, &input[i]);
    index = 0;
  }
  else
  {
    i = 0;
  };
  /* Buffer remaining input. */
  memcpy((i8 *)&ctxt->buffer[index],
             (i8 *)&input[i],
             inputLen-i);
}

void MD5Update(ui8 *input,
               ui32 inputLen)
{
  MD5Update(&context, input, inputLen);
}

/* MD5 finalization.  Ends an MD5 message-digest operation, writing the
   message digest and zeroizing the context.
 */
void MD5Final(ui8 *digest, MD5_CTX *ctxt)
{
  unsigned char bits[8];
  unsigned int index, padLen;
  /* Save number of bits */
  Encode(bits, ctxt->count, 8);
  /* Pad out to 56 mod 64. */
  index = (unsigned int)((ctxt->count[0] >> 3) & 0x3f);
  padLen = (index <56) ? (56 - index) : (120 - index);
  MD5Update(ctxt, PADDING, padLen);
  /* Append Length (before padding) */
  MD5Update(ctxt, bits, 8);
  /* Store state in digest. */
  Encode(digest, ctxt->state, 16);
  /* Zeroize sensitive information. */
  memset ((i8 *)ctxt, 0, sizeof (*ctxt));
}

void MD5Final(ui8 *digest)
{
  MD5Final(digest, &context);
}

/* MD5 basic transformation.  Transform state based on block. */
void MD5Transform (ui32 state[4],unsigned char block[64])
{
  ui32 a=state[0], b=state[1], c=state[2], d=state[3];//, x[16];
  ui32 *x = (ui32 *)block;
  //Decode(x, block, 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],S22,0x02441453); /* 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],S34,0x04881d05); /* 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;

  /* Zeroize sensitive information */
  memset ((i8 *)x, 0, sizeof (x));
}

/* Encodes input (ui32) into output (unsigned char). Assumes
   len is a multiple of 4. */
static void Encode(unsigned char *output, 
                   ui32 *input, 
                   unsigned int len)
{
  unsigned int i, j;
  for (i=0, j=0; j<len; i++, j+=4)
  {
    output[j+0] = (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);
  };
}

/* Decodes input (unsigned char) into output (ui32); Assumes
   len is a multiple of 4. */
/*
static void Decode(ui32 *output,
                   unsigned char *input,
                   unsigned int len)
{
  unsigned int i, j;
  for (i=0, j=0; j<len; i++, j+=4)
  {
    output[i] =   (((ui32)input[j  ])      )
                | (((ui32)input[j+1]) <<  8) 
                | (((ui32)input[j+2]) << 16) 
                | (((ui32)input[j+3]) << 24) ;
  };
}
*/
/* Note: Replace "for loop" with standard memcpy if possible. */
/*
static void MD5_memcpy(i8 *output, i8 *input, unsigned int len)
{
  unsigned int i;
  for (i=0; i<len; i++) output[i] = input[i];
}
*/
/* Note: Replace "for loop" with standard memset if possible. */
/*
static void MD5_memset(i8 *output, int value, unsigned int len)
{
  unsigned int i;
  for (i=0; i<len; i++) (output)[i] = (i8)value;
}
*/