//  MD52DLL.C

/* This code implements the MD5 message-digest algorithm.  To compute
 * the message digest of a chunk of bytes, declare an MD5Context
 * structure, pass it to MD5Init, call MD5Update as needed on
 * buffers full of bytes, and then call MD5Final, which will fill a
 * supplied 16-byte array with the digest.
 *
 * Equivalent code is available from RSA Data Security, Inc.  This code
 * has been tested against that, and is equivalent, except that you
 * don't need to include two pages of legalese with every copy.
 */

#include <memory.h>

#include "stdafx.h"

#define LITTLE_ENDIAN 1

typedef unsigned long uint32;

struct MD5Context 
    {
    uint32 buf[4];
    uint32 bits[2];
    unsigned char in[64];
    };

__declspec(dllexport) void _stdcall MD5Init2(struct MD5Context *);
__declspec(dllexport) void _stdcall MD5Update2(struct MD5Context *x, unsigned char *buf, unsigned len);
__declspec(dllexport) void _stdcall MD5Final2(unsigned char digest[16], struct MD5Context *x);
__declspec(dllexport) void _stdcall Transform2(uint32 buf[4], uint32 in[16]);


 //  Entry point for DLL
/*---------------------------------*/
BOOL APIENTRY DllMain(HANDLE hModule, 
                      DWORD  ul_reason_for_call, 
                      LPVOID lpReserved)
{
return ( TRUE );
}

#if LITTLE_ENDIAN
#define byteReverse(buf, len)    /* Nothing */
#else
void byteReverse(unsigned char *buf, unsigned longs);
#ifndef ASM
/*
 * Note: this code is harmless on big-endian machines.
 */
void byteReverse(unsigned char *buf, unsigned longs)
{
    uint32 t;
    do {
        t = (((((buf[3] << 8) | buf[2]) << 8) | buf[1]) << 8) | buf[0];
        *(uint32 *)buf = t;
        buf += 4;
    } while (--longs);
}
#endif
#endif

/*
 * Start MD5 accumulation.  Set bit count to 0 and buffer to mysterious
 * initialization constants.
 */
/*------------------------------------------*/
void _stdcall MD5Init2(struct MD5Context *ctx)
{
ctx->buf[0] = 0x67452301;
ctx->buf[1] = 0xEFCDAB89;
ctx->buf[2] = 0x98BADCFE;
ctx->buf[3] = 0x10325476;

ctx->bits[0] = 0;
ctx->bits[1] = 0;
}

/* Update context to reflect the concatenation of another buffer full
 * of bytes.
 */
/*------------------------------------------------------------------------------*/
void _stdcall MD5Update2(struct MD5Context *ctx, unsigned char *buf, unsigned len)
{
uint32 t;

/* Update bitcount */

t = ctx->bits[0];
if ((ctx->bits[0] = t + ((uint32)len << 3)) < t)
    ctx->bits[1]++; /* Carry from low to high */
ctx->bits[1] += len >> 29;

t = (t >> 3) & 0x3f;    /* Bytes already in shsInfo->data */

/* Handle any leading odd-sized chunks */

if ( t ) {
    unsigned char *p = (unsigned char *)ctx->in + t;

    t = 64-t;
    //  if (len < t) {
    if ( (uint32)len < t) {
        memcpy(p, buf, len);
        return;
        }
    //  memcpy(p, buf, t);
    memcpy(p, buf, (unsigned)t);
    byteReverse(ctx->in, 16);
    Transform2(ctx->buf, (uint32 *)ctx->in);
    buf += t;
    //  len -= t;
    len -= (unsigned)t;
    }

/* Process data in SHS_BLOCKSIZE chunks */

while (len >= 64) {
    memcpy(ctx->in, buf, 64);
    byteReverse(ctx->in, 16);
    Transform2(ctx->buf, (uint32 *)ctx->in);
    buf += 64;
    len -= 64;
    }

/* Handle any remaining bytes of data. */

memcpy(ctx->in, buf, len);
}

/* Final wrapup - pad to 64-byte boundary with the bit pattern
 * 1 0* (64-bit count of bits processed, MSB-first)
 */
/*---------------------------------------------------------------------*/
void _stdcall MD5Final2(unsigned char digest[16], struct MD5Context *ctx)
{
unsigned count;
unsigned char *p;

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

/* Set the first char of padding to 0x80.  This is safe since there is
   always at least one byte free */
p = ctx->in + count;
*p++ = 0x80;

/* Bytes of padding needed to make 64 bytes */
count = 64 - 1 - count;

/* Pad out to 56 mod 64 */
if (count < 8) {
    /* Two lots of padding:  Pad the first block to 64 bytes */
    memset(p, 0, count);
    byteReverse(ctx->in, 16);
    Transform2(ctx->buf, (uint32 *)ctx->in);

    /* Now fill the next block with 56 bytes */
    memset(ctx->in, 0, 56);
    }
else {
    /* Pad block to 56 bytes */
    memset(p, 0, count-8);
    }
byteReverse(ctx->in, 14);

/* Append length in bits and transform */
((uint32 *)ctx->in)[ 14 ] = ctx->bits[0];
((uint32 *)ctx->in)[ 15 ] = ctx->bits[1];

Transform2(ctx->buf, (uint32 *)ctx->in);
memcpy(digest, ctx->buf, 16);
byteReverse(digest, 4);

//  return ( digest );
}

#ifndef ASM

/* The four core functions - F1 is optimized somewhat */

/* #define F1(x, y, z) (x & y | ~x & z) */
#define F1(x, y, z) (z ^ (x & (y ^ z)))
#define F2(x, y, z) F1(z, x, y)
#define F3(x, y, z) (x ^ y ^ z)
#define F4(x, y, z) (y ^ (x | ~z))

/* This is the central step in the MD5 algorithm. */
#define MD5STEP(f, w, x, y, z, data, s) \
    ( w += f(x, y, z) + data,  w = w<<s | w>>(32-s),  w += x )

/* The core of the MD5 algorithm, this alters an existing MD5 hash to
 * reflect the addition of 16 longwords of new data.  MD5Update blocks
 * the data and converts bytes into longwords for this routine.
 */
/*--------------------------------------------------*/
void _stdcall Transform2(uint32 buf[4], uint32 in[16])
{
register uint32 a, b, c, d;

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

MD5STEP(F1, a, b, c, d, in[ 0]+0xd76aa478,  7);
MD5STEP(F1, d, a, b, c, in[ 1]+0xe8c7b756, 12);
MD5STEP(F1, c, d, a, b, in[ 2]+0x242070db, 17);
MD5STEP(F1, b, c, d, a, in[ 3]+0xc1bdceee, 22);
MD5STEP(F1, a, b, c, d, in[ 4]+0xf57c0faf,  7);
MD5STEP(F1, d, a, b, c, in[ 5]+0x4787c62a, 12);
MD5STEP(F1, c, d, a, b, in[ 6]+0xa8304613, 17);
MD5STEP(F1, b, c, d, a, in[ 7]+0xfd469501, 22);
MD5STEP(F1, a, b, c, d, in[ 8]+0x698098d8,  7);
MD5STEP(F1, d, a, b, c, in[ 9]+0x8b44f7af, 12);
MD5STEP(F1, c, d, a, b, in[10]+0xffff5bb1, 17);
MD5STEP(F1, b, c, d, a, in[11]+0x895cd7be, 22);
MD5STEP(F1, a, b, c, d, in[12]+0x6b901122,  7);
MD5STEP(F1, d, a, b, c, in[13]+0xfd987193, 12);
MD5STEP(F1, c, d, a, b, in[14]+0xa679438e, 17);
MD5STEP(F1, b, c, d, a, in[15]+0x49b40821, 22);

MD5STEP(F2, a, b, c, d, in[ 1]+0xf61e2562,  5);
MD5STEP(F2, d, a, b, c, in[ 6]+0xc040b340,  9);
MD5STEP(F2, c, d, a, b, in[11]+0x265e5a51, 14);
MD5STEP(F2, b, c, d, a, in[ 0]+0xe9b6c7aa, 20);
MD5STEP(F2, a, b, c, d, in[ 5]+0xd62f105d,  5);
MD5STEP(F2, d, a, b, c, in[10]+0x02441453,  9);
MD5STEP(F2, c, d, a, b, in[15]+0xd8a1e681, 14);
MD5STEP(F2, b, c, d, a, in[ 4]+0xe7d3fbc8, 20);
MD5STEP(F2, a, b, c, d, in[ 9]+0x21e1cde6,  5);
MD5STEP(F2, d, a, b, c, in[14]+0xc33707d6,  9);
MD5STEP(F2, c, d, a, b, in[ 3]+0xf4d50d87, 14);
MD5STEP(F2, b, c, d, a, in[ 8]+0x455a14ed, 20);
MD5STEP(F2, a, b, c, d, in[13]+0xa9e3e905,  5);
MD5STEP(F2, d, a, b, c, in[ 2]+0xfcefa3f8,  9);
MD5STEP(F2, c, d, a, b, in[ 7]+0x676f02d9, 14);
MD5STEP(F2, b, c, d, a, in[12]+0x8d2a4c8a, 20);

MD5STEP(F3, a, b, c, d, in[ 5]+0xfffa3942,  4);
MD5STEP(F3, d, a, b, c, in[ 8]+0x8771f681, 11);
MD5STEP(F3, c, d, a, b, in[11]+0x6d9d6122, 16);
MD5STEP(F3, b, c, d, a, in[14]+0xfde5380c, 23);
MD5STEP(F3, a, b, c, d, in[ 1]+0xa4beea44,  4);
MD5STEP(F3, d, a, b, c, in[ 4]+0x4bdecfa9, 11);
MD5STEP(F3, c, d, a, b, in[ 7]+0xf6bb4b60, 16);
MD5STEP(F3, b, c, d, a, in[10]+0xbebfbc70, 23);
MD5STEP(F3, a, b, c, d, in[13]+0x289b7ec6,  4);
MD5STEP(F3, d, a, b, c, in[ 0]+0xeaa127fa, 11);
MD5STEP(F3, c, d, a, b, in[ 3]+0xd4ef3085, 16);
MD5STEP(F3, b, c, d, a, in[ 6]+0x04881d05, 23);
MD5STEP(F3, a, b, c, d, in[ 9]+0xd9d4d039,  4);
MD5STEP(F3, d, a, b, c, in[12]+0xe6db99e5, 11);
MD5STEP(F3, c, d, a, b, in[15]+0x1fa27cf8, 16);
MD5STEP(F3, b, c, d, a, in[ 2]+0xc4ac5665, 23);

MD5STEP(F4, a, b, c, d, in[ 0]+0xf4292244,  6);
MD5STEP(F4, d, a, b, c, in[ 7]+0x432aff97, 10);
MD5STEP(F4, c, d, a, b, in[14]+0xab9423a7, 15);
MD5STEP(F4, b, c, d, a, in[ 5]+0xfc93a039, 21);
MD5STEP(F4, a, b, c, d, in[12]+0x655b59c3,  6);
MD5STEP(F4, d, a, b, c, in[ 3]+0x8f0ccc92, 10);
MD5STEP(F4, c, d, a, b, in[10]+0xffeff47d, 15);
MD5STEP(F4, b, c, d, a, in[ 1]+0x85845dd1, 21);
MD5STEP(F4, a, b, c, d, in[ 8]+0x6fa87e4f,  6);
MD5STEP(F4, d, a, b, c, in[15]+0xfe2ce6e0, 10);
MD5STEP(F4, c, d, a, b, in[ 6]+0xa3014314, 15);
MD5STEP(F4, b, c, d, a, in[13]+0x4e0811a1, 21);
MD5STEP(F4, a, b, c, d, in[ 4]+0xf7537e82,  6);
MD5STEP(F4, d, a, b, c, in[11]+0xbd3af235, 10);
MD5STEP(F4, c, d, a, b, in[ 2]+0x2ad7d2bb, 15);
MD5STEP(F4, b, c, d, a, in[ 9]+0xeb86d391, 21);

buf[0] += a;
buf[1] += b;
buf[2] += c;
buf[3] += d;
}
#endif