/*
 * 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.
 */

#include <string.h>		/* for memcpy() */

#include "doomtype.h"
#include "md5.h"
#include "templates.h"

#ifdef WORDS_BIGENDIAN
void byteSwap(DWORD *buf, unsigned words)
{
	BYTE *p = (BYTE *)buf;

	do {
		*buf++ = (DWORD)((unsigned)p[3] << 8 | p[2]) << 16 |
			((unsigned)p[1] << 8 | p[0]);
		p += 4;
	} while (--words);
}
#else
#define byteSwap(buf,words)
#endif

/*
 * Start MD5 accumulation.  Set bit count to 0 and buffer to mysterious
 * initialization constants.
 */
void MD5Context::Init()
{
	buf[0] = 0x67452301;
	buf[1] = 0xefcdab89;
	buf[2] = 0x98badcfe;
	buf[3] = 0x10325476;

	bytes[0] = 0;
	bytes[1] = 0;
}

/*
 * Update context to reflect the concatenation of another buffer full
 * of bytes.
 */
void MD5Context::Update(const BYTE *buf, unsigned len)
{
	DWORD t;

	/* Update byte count */

	t = bytes[0];
	if ((bytes[0] = t + len) < t)
		bytes[1]++;	/* Carry from low to high */

	t = 64 - (t & 0x3f);	/* Space available in ctx->in (at least 1) */
	if (t > len) {
		memcpy((BYTE *)in + 64 - t, buf, len);
		return;
	}
	/* First chunk is an odd size */
	if (t < 64)
	{
		memcpy((BYTE *)in + 64 - t, buf, t);
		byteSwap(in, 16);
		MD5Transform(this->buf, in);
		buf += t;
		len -= t;
	}

	/* Process data in 64-byte chunks */
	while (len >= 64)
	{
		memcpy(in, buf, 64);
		byteSwap(in, 16);
		MD5Transform(this->buf, in);
		buf += 64;
		len -= 64;
	}

	/* Handle any remaining bytes of data. */
	memcpy(in, buf, len);
}

void MD5Context::Update(FileReader *file, unsigned len)
{
	BYTE readbuf[8192];
	long t;

	while (len != 0)
	{
		t = MIN(len, sizeof(readbuf));
		len -= t;
		t = file->Read(readbuf, t);
		Update(readbuf, t);
	}
}

/*
 * Final wrapup - pad to 64-byte boundary with the bit pattern 
 * 1 0* (64-bit count of bits processed, MSB-first)
 */
void MD5Context::Final(BYTE digest[16])
{
	int count = bytes[0] & 0x3f;	/* Number of bytes in ctx->in */
	BYTE *p = (BYTE *)in + count;

	/* Set the first char of padding to 0x80.  There is always room. */
	*p++ = 0x80;

	/* Bytes of padding needed to make 56 bytes (-8..55) */
	count = 56 - 1 - count;

	if (count < 0)		/* Padding forces an extra block */
	{
		memset(p, 0, count + 8);
		byteSwap(in, 16);
		MD5Transform(buf, in);
		p = (BYTE *)in;
		count = 56;
	}
	memset(p, 0, count);
	byteSwap(in, 14);

	/* Append length in bits and transform */
	in[14] = bytes[0] << 3;
	in[15] = (bytes[1] << 3) | (bytes[0] >> 29);
	MD5Transform(buf, in);

	byteSwap(buf, 4);
	memcpy(digest, buf, 16);
	memset(this, 0, sizeof(*this));	/* In case it's sensitive */
}

#ifndef ASM_MD5

/* 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,in,s) \
	 (w += f(x,y,z) + in, w = (w<<s | w>>(32-s)) + 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
MD5Transform(DWORD buf[4], const DWORD in[16])
{
	register DWORD 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

#include "c_dispatch.h"

//==========================================================================
//
// CCMD md5sum
//
// Like the command-line tool, because I wanted to make sure I had it right.
//
//==========================================================================

CCMD (md5sum)
{
	if (argv.argc() < 2)
	{
		Printf("Usage: md5sum <file> ...\n");
	}
	for (int i = 1; i < argv.argc(); ++i)
	{
		FILE *file = fopen(argv[i], "rb");
		if (file == NULL)
		{
			Printf("%s: %s\n", argv[i], strerror(errno));
		}
		else
		{
			MD5Context md5;
			BYTE readbuf[8192];
			size_t len;

			while ((len = fread(readbuf, 1, sizeof(readbuf), file)) > 0)
			{
				md5.Update(readbuf, (unsigned int)len);
			}
			md5.Final(readbuf);
			for(int j = 0; j < 16; ++j)
			{
				Printf("%02x", readbuf[j]);
			}
			Printf(" *%s\n", argv[i]);
			fclose (file);
		}
	}
}