/*
 * This code implements the MD5 message-digest algorithm.
 * The algorithm is due to Ron Rivest.  This code was
 * written by Colin Plumb in 1993, no copyright is claimed.
 * This code is in the public domain; do with it what you wish.
 *
 * 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.
 *
 * 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.
 */

/* This code slightly modified to fit into Samba by 
   abartlet@samba.org Jun 2001 
   and to fit the cifs vfs by 
   Steve French sfrench@us.ibm.com */

/* Replacement of  __u32 with guint32,
   removal of hmac* functions
   and addition of AsciiDigest(), print_sum() and main()
   by Carsten Gnörlich for the dvdisaster project, 2004-2006. */

/* byteReverse() and MD5Final() changed for clean endian-independent 
   guint32->unsigned char conversion 
   by Carsten Gnörlich for the dvdisaster project, 2015. */

#if defined(SIMPLE_MD5SUM)    	/* simple-md5sum*/
  #include <string.h>
#else                           /* dvdisaster */
  #include "dvdisaster.h"
#endif

#include "md5.h"

static void MD5Transform(guint32 buf[4], guint32 const in[16]);

/*
 * Note: this code is harmless on little-endian machines.
 */

#ifdef HAVE_LITTLE_ENDIAN
  #define byteReverse(buf, longs)	/* even more harmless */
#else
static void
byteReverse(unsigned char *buf, unsigned longs)
{
	guint32 t;
	do {
		t = buf[0]; buf[0] = buf[3]; buf[3] = t;	
		t = buf[1]; buf[1] = buf[2]; buf[2] = t;	
		buf += 4;
	} while (--longs);
}
#endif

/*
 * Start MD5 accumulation.  Set bit count to 0 and buffer to mysterious
 * initialization constants.
 */
void
MD5Init(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
MD5Update(struct MD5Context *ctx, unsigned char const *buf, unsigned len)
{
	register guint32 t;

	/* Update bitcount */

	t = ctx->bits[0];
	if ((ctx->bits[0] = t + ((guint32) 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) {
			memmove(p, buf, len);
			return;
		}
		memmove(p, buf, t);
		byteReverse(ctx->in, 16);
		MD5Transform(ctx->buf, (guint32 *) ctx->in);
		buf += t;
		len -= t;
	}
	/* Process data in 64-byte chunks */

	while (len >= 64) {
		memmove(ctx->in, buf, 64);
		byteReverse(ctx->in, 16);
		MD5Transform(ctx->buf, (guint32 *) ctx->in);
		buf += 64;
		len -= 64;
	}

	/* Handle any remaining bytes of data. */

	memmove(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
MD5Final(unsigned char digest[16], struct MD5Context *ctx)
{
	unsigned int count;
	unsigned char *p;
	unsigned char *in;
		
	/* Compute number of bytes mod 64 */
	count = (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);
		MD5Transform(ctx->buf, (guint32 *) 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 */
	/* changed by cg to prevent compiler warnings */

	in = &ctx->in[56];

#ifdef HAVE_LITTLE_ENDIAN
	*in++ = (unsigned char)((ctx->bits[0]      ) & 0xff);
	*in++ = (unsigned char)((ctx->bits[0] >>  8) & 0xff);
	*in++ = (unsigned char)((ctx->bits[0] >> 16) & 0xff);
	*in++ = (unsigned char)((ctx->bits[0] >> 24) & 0xff);
	*in++ = (unsigned char)((ctx->bits[1]      ) & 0xff);
	*in++ = (unsigned char)((ctx->bits[1] >>  8) & 0xff);
	*in++ = (unsigned char)((ctx->bits[1] >> 16) & 0xff);
	*in++ = (unsigned char)((ctx->bits[1] >> 24) & 0xff);
#else
	*in++ = (unsigned char)((ctx->bits[0] >> 24) & 0xff);
	*in++ = (unsigned char)((ctx->bits[0] >> 16) & 0xff);
	*in++ = (unsigned char)((ctx->bits[0] >>  8) & 0xff);
	*in++ = (unsigned char)((ctx->bits[0]      ) & 0xff);
	*in++ = (unsigned char)((ctx->bits[1] >> 24) & 0xff);
	*in++ = (unsigned char)((ctx->bits[1] >> 16) & 0xff);
	*in++ = (unsigned char)((ctx->bits[1] >>  8) & 0xff);
	*in++ = (unsigned char)((ctx->bits[1]      ) & 0xff);
#endif

	MD5Transform(ctx->buf, (guint32 *) ctx->in);
	byteReverse((unsigned char *) ctx->buf, 4);
	memmove(digest, ctx->buf, 16);
	memset(ctx, 0, sizeof(struct MD5Context));	/* In case it's sensitive */
}

/* 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.
 */
static void
MD5Transform(guint32 buf[4], guint32 const in[16])
{
	register guint32 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;
}

/***
 *** The following functions have been added for the dvdisaster project.
 ***/

/*
 * Convert md5 digest into printable format.
 */

static char hextab[] = "0123456789abcdef";

void AsciiDigest(char *out, unsigned char *in)
{  int i,o;

   for(i=0, o=0; i<16; i++)
   {  out[o++] = hextab[in[i]>>4];
      out[o++] = hextab[in[i]&0x0f];
   }
   out[o] = 0;
}

/*
 * Wrapper for creating a simple md5sum binary.
 * This emulates "md5sum -b", as md5sum is not available per
 * default on all target platforms. 
 */

#ifdef SIMPLE_MD5SUM

#include <stdio.h>

static void print_sum(char *path)
{  FILE *file;
   struct MD5Context ctxt;
   unsigned char buf[32768];
   unsigned char digest[16];
   char ascii_digest[33];
   int size = 0;

   file = fopen(path, "rb");
   if(!file) return;

   MD5Init(&ctxt);

   while(!feof(file))
   {  int n = fread(buf, 1, 32768, file);
      if(!n) break;

      MD5Update(&ctxt, buf, n);
      size += n;
   }

   MD5Final(digest, &ctxt);
   AsciiDigest(ascii_digest, digest);
   printf("%s *%s\n", ascii_digest, path);

   fclose(file);
}


int main(int argc, char *argv[])
{  int i;

   for(i=1; i<argc; i++)
     print_sum(argv[i]);

  return 0;
}

#endif
