text: #include "MD5.h"
  
  #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))
  
  #define MD5STEP(f, w, x, y, z, data, s) \
  		( w += f(x, y, z) + data,  w = w<<s | w>>(32-s),  w += x )
  
  static void MD5Transform(unsigned buf[4], unsigned const in[16])
  {
  	register unsigned 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;
  }
  
  void MD5Init(MD5Context_t *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;
  }
  
  void MD5Update(MD5Context_t *ctx, unsigned char const *buf, unsigned len)
  {
  	unsigned t;
  
  	t = ctx->bits[0];
  	if ((ctx->bits[0] = t + ((unsigned)len << 3)) < t)
  		ctx->bits[1]++;
  	ctx->bits[1] += len >> 29;
  
  	t = (t >> 3) & 0x3f;
  
  	if (t)
  	{
  		unsigned char *p = (unsigned char *)ctx->in + t;
  
  		t = 64 - t;
  		if (len < t)
  		{
  			memcpy(p, buf, len);
  			return;
  		}
  		memcpy(p, buf, t);
  		//byteReverse(ctx->in, 16);
  		MD5Transform(ctx->buf, (unsigned *)ctx->in);
  		buf += t;
  		len -= t;
  	}
  
  	while (len >= 64)
  	{
  		memcpy(ctx->in, buf, 64);
  		//byteReverse(ctx->in, 16);
  		MD5Transform(ctx->buf, (unsigned *)ctx->in);
  		buf += 64;
  		len -= 64;
  	}
  
  	memcpy(ctx->in, buf, len);
  }
  
  void MD5Final(unsigned char digest[MD5_DIGEST_LENGTH], MD5Context_t *ctx)
  {
  	unsigned count;
  	unsigned char *p;
  
  	count = (ctx->bits[0] >> 3) & 0x3F;
  
  	p = ctx->in + count;
  	*p++ = 0x80;
  
  	count = 64 - 1 - count;
  
  	if (count < 8)
  	{
  		memset(p, 0, count);
  		//byteReverse(ctx->in, 16);
  		MD5Transform(ctx->buf, (unsigned *)ctx->in);
  
  		memset(ctx->in, 0, 56);
  	}
  	else
  	{
  		memset(p, 0, count - 8);
  	}
  	//byteReverse(ctx->in, 14);
  
  	((unsigned *)ctx->in)[14] = ctx->bits[0];
  	((unsigned *)ctx->in)[15] = ctx->bits[1];
  
  	MD5Transform(ctx->buf, (unsigned *)ctx->in);
  	//byteReverse((unsigned char *) ctx->buf, 4);
  	memcpy(digest, ctx->buf, MD5_DIGEST_LENGTH);
  	memset(ctx, 0, sizeof(ctx));
  }
  
  unsigned MD5_PseudoRandom(unsigned nSeed)
  {
  	MD5Context_t ctx;
  	unsigned char digest[MD5_DIGEST_LENGTH]; // The MD5 Hash
  
  	memset(&ctx, 0, sizeof(ctx));
  
  	MD5Init(&ctx);
  	MD5Update(&ctx, (unsigned char*)&nSeed, sizeof(nSeed));
  	MD5Final(digest, &ctx);
  
  	return *(unsigned*)(digest + 6);	// use 4 middle bytes for random value
  }