/*
 * Copyright (C) 1999, 2000, 2002 Aladdin Enterprises.  All rights reserved.
 *
 * This software is provided 'as-is', without any express or implied
 * warranty.  In no event will the authors be held liable for any damages
 * arising from the use of this software.
 *
 * Permission is granted to anyone to use this software for any purpose,
 * including commercial applications, and to alter it and redistribute it
 * freely, subject to the following restrictions:
 *
 * 1. The origin of this software must not be misrepresented; you must not
 *   claim that you wrote the original software. If you use this software
 *   in a product, an acknowledgment in the product documentation would be
 *   appreciated but is not required.
 * 2. Altered source versions must be plainly marked as such, and must not be
 *   misrepresented as being the original software.
 * 3. This notice may not be removed or altered from any source distribution.
 *
 * L. Peter Deutsch
 * ghost@aladdin.com
 *
 */
/* $Id$ */

/*
 * Independent implementation of MD5 (RFC 1321).
 *
 * This code implements the MD5 Algorithm defined in RFC 1321, whose
 * text is available at
 *  http://www.ietf.org/rfc/rfc1321.txt
 * The code is derived from the text of the RFC, including the test suite
 * (section A.5) but excluding the rest of Appendix A.  It does not include
 * any code or documentation that is identified in the RFC as being
 * copyrighted.
 *
 * The original and principal author of md5.c is L. Peter Deutsch
 * <ghost@aladdin.com>.  Other authors are noted in the change history
 * that follows (in reverse chronological order):
 *
 * 2002-04-13 lpd Clarified derivation from RFC 1321; now handles byte order
 *  either statically or dynamically; added missing #include <string.h>
 *  in library.
 * 2002-03-11 lpd Corrected argument list for main(), and added int return
 *  type, in test program and T value program.
 * 2002-02-21 lpd Added missing #include <stdio.h> in test program.
 * 2000-07-03 lpd Patched to eliminate warnings about "constant is
 *  unsigned in ANSI C, signed in traditional"; made test program
 *  self-checking.
 * 1999-11-04 lpd Edited comments slightly for automatic TOC extraction.
 * 1999-10-18 lpd Fixed typo in header comment (ansi2knr rather than md5).
 * 1999-05-03 lpd Original version.
 */

#include "md5.h"
#include <string.h>

#undef BYTE_ORDER       /* 1 = big-endian, -1 = little-endian, 0 = unknown */
#ifdef ARCH_IS_BIG_ENDIAN
	#define BYTE_ORDER	(ARCH_IS_BIG_ENDIAN ? 1 : -1)
#else
	#define BYTE_ORDER	0
#endif

#define T_MASK			((md5_word_t) ~0)
#define T1                      /* 0xd76aa478 */ (T_MASK ^ 0x28955b87)
#define T2                      /* 0xe8c7b756 */ (T_MASK ^ 0x173848a9)
#define T3			0x242070db
#define T4                      /* 0xc1bdceee */ (T_MASK ^ 0x3e423111)
#define T5                      /* 0xf57c0faf */ (T_MASK ^ 0x0a83f050)
#define T6			0x4787c62a
#define T7                      /* 0xa8304613 */ (T_MASK ^ 0x57cfb9ec)
#define T8                      /* 0xfd469501 */ (T_MASK ^ 0x02b96afe)
#define T9			0x698098d8
#define T10                     /* 0x8b44f7af */ (T_MASK ^ 0x74bb0850)
#define T11                     /* 0xffff5bb1 */ (T_MASK ^ 0x0000a44e)
#define T12                     /* 0x895cd7be */ (T_MASK ^ 0x76a32841)
#define T13			0x6b901122
#define T14                     /* 0xfd987193 */ (T_MASK ^ 0x02678e6c)
#define T15                     /* 0xa679438e */ (T_MASK ^ 0x5986bc71)
#define T16			0x49b40821
#define T17                     /* 0xf61e2562 */ (T_MASK ^ 0x09e1da9d)
#define T18                     /* 0xc040b340 */ (T_MASK ^ 0x3fbf4cbf)
#define T19			0x265e5a51
#define T20                     /* 0xe9b6c7aa */ (T_MASK ^ 0x16493855)
#define T21                     /* 0xd62f105d */ (T_MASK ^ 0x29d0efa2)
#define T22			0x02441453
#define T23                     /* 0xd8a1e681 */ (T_MASK ^ 0x275e197e)
#define T24                     /* 0xe7d3fbc8 */ (T_MASK ^ 0x182c0437)
#define T25			0x21e1cde6
#define T26                     /* 0xc33707d6 */ (T_MASK ^ 0x3cc8f829)
#define T27                     /* 0xf4d50d87 */ (T_MASK ^ 0x0b2af278)
#define T28			0x455a14ed
#define T29                     /* 0xa9e3e905 */ (T_MASK ^ 0x561c16fa)
#define T30                     /* 0xfcefa3f8 */ (T_MASK ^ 0x03105c07)
#define T31			0x676f02d9
#define T32                     /* 0x8d2a4c8a */ (T_MASK ^ 0x72d5b375)
#define T33                     /* 0xfffa3942 */ (T_MASK ^ 0x0005c6bd)
#define T34                     /* 0x8771f681 */ (T_MASK ^ 0x788e097e)
#define T35			0x6d9d6122
#define T36                     /* 0xfde5380c */ (T_MASK ^ 0x021ac7f3)
#define T37                     /* 0xa4beea44 */ (T_MASK ^ 0x5b4115bb)
#define T38			0x4bdecfa9
#define T39                     /* 0xf6bb4b60 */ (T_MASK ^ 0x0944b49f)
#define T40                     /* 0xbebfbc70 */ (T_MASK ^ 0x4140438f)
#define T41			0x289b7ec6
#define T42                     /* 0xeaa127fa */ (T_MASK ^ 0x155ed805)
#define T43                     /* 0xd4ef3085 */ (T_MASK ^ 0x2b10cf7a)
#define T44			0x04881d05
#define T45                     /* 0xd9d4d039 */ (T_MASK ^ 0x262b2fc6)
#define T46                     /* 0xe6db99e5 */ (T_MASK ^ 0x1924661a)
#define T47			0x1fa27cf8
#define T48                     /* 0xc4ac5665 */ (T_MASK ^ 0x3b53a99a)
#define T49                     /* 0xf4292244 */ (T_MASK ^ 0x0bd6ddbb)
#define T50			0x432aff97
#define T51                     /* 0xab9423a7 */ (T_MASK ^ 0x546bdc58)
#define T52                     /* 0xfc93a039 */ (T_MASK ^ 0x036c5fc6)
#define T53			0x655b59c3
#define T54                     /* 0x8f0ccc92 */ (T_MASK ^ 0x70f3336d)
#define T55                     /* 0xffeff47d */ (T_MASK ^ 0x00100b82)
#define T56                     /* 0x85845dd1 */ (T_MASK ^ 0x7a7ba22e)
#define T57			0x6fa87e4f
#define T58                     /* 0xfe2ce6e0 */ (T_MASK ^ 0x01d3191f)
#define T59                     /* 0xa3014314 */ (T_MASK ^ 0x5cfebceb)
#define T60			0x4e0811a1
#define T61                     /* 0xf7537e82 */ (T_MASK ^ 0x08ac817d)
#define T62                     /* 0xbd3af235 */ (T_MASK ^ 0x42c50dca)
#define T63			0x2ad7d2bb
#define T64                     /* 0xeb86d391 */ (T_MASK ^ 0x14792c6e)

static void
md5_process(md5_state_t *pms, const md5_byte_t *data /*[64]*/)
{
	md5_word_t
	    a = pms->abcd[0], b = pms->abcd[1],
	    c = pms->abcd[2], d = pms->abcd[3];
	md5_word_t t;

#if BYTE_ORDER > 0
		/* Define storage only for big-endian CPUs. */
		md5_word_t X[16];
#else
		/* Define storage for little-endian or both types of CPUs. */
		md5_word_t xbuf[16];
		const md5_word_t *X;
#endif

	{
#if BYTE_ORDER == 0

			/*
			 * Determine dynamically whether this is a big-endian or
			 * little-endian machine, since we can use a more efficient
			 * algorithm on the latter.
			 */
			static const int w = 1;

			if (*((const md5_byte_t *)&w))  /* dynamic little-endian */
#endif
#if BYTE_ORDER <= 0                                     /* little-endian */
			{
				/*
				 * On little-endian machines, we can process properly aligned
				 * data without copying it.
				 */
				if (!((data - (const md5_byte_t *)0) & 3)) {
					/* data are properly aligned */
					X = (const md5_word_t *)data;
				} else {
					/* not aligned */
					memcpy(xbuf, data, 64);
					X = xbuf;
				}
			}
#endif
#if BYTE_ORDER == 0
			else    /* dynamic big-endian */
#endif
#if BYTE_ORDER >= 0             /* big-endian */
			{
				/*
				 * On big-endian machines, we must arrange the bytes in the
				 * right order.
				 */
				const md5_byte_t *xp = data;
				int i;

 #if BYTE_ORDER == 0
					X = xbuf;               /* (dynamic only) */
 #else
					#define xbuf    X       /* (static only) */
 #endif
				for (i = 0; i < 16; ++i, xp += 4) {
					xbuf[i] = xp[0] + (xp[1] << 8) + (xp[2] << 16) + (xp[3] << 24);
				}
			}
#endif
	}

	#define ROTATE_LEFT(x, n)    (((x) << (n)) | ((x) >> (32 - (n))))

	/* Round 1. */

	/* Let [abcd k s i] denote the operation
	 * a = b + ((a + F(b,c,d) + X[k] + T[i]) <<< s). */
	#define F(x, y, z)    (((x) & (y)) | (~(x) & (z)))
	#define SET(a, b, c, d, k, s, Ti)	\
		t = a + F(b, c, d) + X[k] + Ti;	\
		a = ROTATE_LEFT(t, s) + b
	/* Do the following 16 operations. */
	SET(a, b, c, d, 0, 7, T1);
	SET(d, a, b, c, 1, 12, T2);
	SET(c, d, a, b, 2, 17, T3);
	SET(b, c, d, a, 3, 22, T4);
	SET(a, b, c, d, 4, 7, T5);
	SET(d, a, b, c, 5, 12, T6);
	SET(c, d, a, b, 6, 17, T7);
	SET(b, c, d, a, 7, 22, T8);
	SET(a, b, c, d, 8, 7, T9);
	SET(d, a, b, c, 9, 12, T10);
	SET(c, d, a, b, 10, 17, T11);
	SET(b, c, d, a, 11, 22, T12);
	SET(a, b, c, d, 12, 7, T13);
	SET(d, a, b, c, 13, 12, T14);
	SET(c, d, a, b, 14, 17, T15);
	SET(b, c, d, a, 15, 22, T16);
#undef SET

	/* Round 2. */

	/* Let [abcd k s i] denote the operation
	 *   a = b + ((a + G(b,c,d) + X[k] + T[i]) <<< s). */
	#define G(x, y, z)    (((x) & (z)) | ((y) & ~(z)))
	#define SET(a, b, c, d, k, s, Ti)	\
		t = a + G(b, c, d) + X[k] + Ti;	\
		a = ROTATE_LEFT(t, s) + b
	/* Do the following 16 operations. */
	SET(a, b, c, d, 1, 5, T17);
	SET(d, a, b, c, 6, 9, T18);
	SET(c, d, a, b, 11, 14, T19);
	SET(b, c, d, a, 0, 20, T20);
	SET(a, b, c, d, 5, 5, T21);
	SET(d, a, b, c, 10, 9, T22);
	SET(c, d, a, b, 15, 14, T23);
	SET(b, c, d, a, 4, 20, T24);
	SET(a, b, c, d, 9, 5, T25);
	SET(d, a, b, c, 14, 9, T26);
	SET(c, d, a, b, 3, 14, T27);
	SET(b, c, d, a, 8, 20, T28);
	SET(a, b, c, d, 13, 5, T29);
	SET(d, a, b, c, 2, 9, T30);
	SET(c, d, a, b, 7, 14, T31);
	SET(b, c, d, a, 12, 20, T32);
#undef SET

	/* Round 3. */

	/* Let [abcd k s t] denote the operation
	 *   a = b + ((a + H(b,c,d) + X[k] + T[i]) <<< s). */
	#define H(x, y, z)    ((x) ^ (y) ^ (z))
	#define SET(a, b, c, d, k, s, Ti)	\
		t = a + H(b, c, d) + X[k] + Ti;	\
		a = ROTATE_LEFT(t, s) + b
	/* Do the following 16 operations. */
	SET(a, b, c, d, 5, 4, T33);
	SET(d, a, b, c, 8, 11, T34);
	SET(c, d, a, b, 11, 16, T35);
	SET(b, c, d, a, 14, 23, T36);
	SET(a, b, c, d, 1, 4, T37);
	SET(d, a, b, c, 4, 11, T38);
	SET(c, d, a, b, 7, 16, T39);
	SET(b, c, d, a, 10, 23, T40);
	SET(a, b, c, d, 13, 4, T41);
	SET(d, a, b, c, 0, 11, T42);
	SET(c, d, a, b, 3, 16, T43);
	SET(b, c, d, a, 6, 23, T44);
	SET(a, b, c, d, 9, 4, T45);
	SET(d, a, b, c, 12, 11, T46);
	SET(c, d, a, b, 15, 16, T47);
	SET(b, c, d, a, 2, 23, T48);
#undef SET

	/* Round 4. */

	/* Let [abcd k s t] denote the operation
	 *   a = b + ((a + I(b,c,d) + X[k] + T[i]) <<< s). */
	#define I(x, y, z)    ((y) ^ ((x) | ~(z)))
	#define SET(a, b, c, d, k, s, Ti)	\
		t = a + I(b, c, d) + X[k] + Ti;	\
		a = ROTATE_LEFT(t, s) + b
	/* Do the following 16 operations. */
	SET(a, b, c, d, 0, 6, T49);
	SET(d, a, b, c, 7, 10, T50);
	SET(c, d, a, b, 14, 15, T51);
	SET(b, c, d, a, 5, 21, T52);
	SET(a, b, c, d, 12, 6, T53);
	SET(d, a, b, c, 3, 10, T54);
	SET(c, d, a, b, 10, 15, T55);
	SET(b, c, d, a, 1, 21, T56);
	SET(a, b, c, d, 8, 6, T57);
	SET(d, a, b, c, 15, 10, T58);
	SET(c, d, a, b, 6, 15, T59);
	SET(b, c, d, a, 13, 21, T60);
	SET(a, b, c, d, 4, 6, T61);
	SET(d, a, b, c, 11, 10, T62);
	SET(c, d, a, b, 2, 15, T63);
	SET(b, c, d, a, 9, 21, T64);
#undef SET

	/* Then perform the following additions. (That is increment each
	 * of the four registers by the value it had before this block
	 * was started.) */
	pms->abcd[0] += a;
	pms->abcd[1] += b;
	pms->abcd[2] += c;
	pms->abcd[3] += d;
}


void
md5_init(md5_state_t *pms)
{
	pms->count[0] = pms->count[1] = 0;
	pms->abcd[0] = 0x67452301;
	pms->abcd[1] = /*0xefcdab89*/ T_MASK ^ 0x10325476;
	pms->abcd[2] = /*0x98badcfe*/ T_MASK ^ 0x67452301;
	pms->abcd[3] = 0x10325476;
}


void
md5_append(md5_state_t *pms, const md5_byte_t *data, int nbytes)
{
	const md5_byte_t *p = data;
	int left = nbytes;
	int offset = (pms->count[0] >> 3) & 63;
	md5_word_t nbits = (md5_word_t)(nbytes << 3);

	if (nbytes <= 0) {
		return;
	}

	/* Update the message length. */
	pms->count[1] += nbytes >> 29;
	pms->count[0] += nbits;
	if (pms->count[0] < nbits) {
		pms->count[1]++;
	}

	/* Process an initial partial block. */
	if (offset) {
		int copy = (offset + nbytes > 64 ? 64 - offset : nbytes);

		memcpy(pms->buf + offset, p, copy);
		if (offset + copy < 64) {
			return;
		}
		p += copy;
		left -= copy;
		md5_process(pms, pms->buf);
	}

	/* Process full blocks. */
	for ( ; left >= 64; p += 64, left -= 64) {
		md5_process(pms, p);
	}

	/* Process a final partial block. */
	if (left) {
		memcpy(pms->buf, p, left);
	}
}


void
md5_finish(md5_state_t *pms, md5_byte_t digest[16])
{
	static const md5_byte_t pad[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
	};
	md5_byte_t data[8];
	int i;

	/* Save the length before padding. */
	for (i = 0; i < 8; ++i) {
		data[i] = (md5_byte_t)(pms->count[i >> 2] >> ((i & 3) << 3));
	}
	/* Pad to 56 bytes mod 64. */
	md5_append(pms, pad, ((55 - (pms->count[0] >> 3)) & 63) + 1);
	/* Append the length. */
	md5_append(pms, data, 8);
	for (i = 0; i < 16; ++i) {
		digest[i] = (md5_byte_t)(pms->abcd[i >> 2] >> ((i & 3) << 3));
	}
}


static const char hexchar[] = "0123456789abcdef";

char *
md5_hex(const char *bytes, int nbytes)
{
	char out[33];
	char *o = out + 32;
	char digest[16];
	char *digestp = digest + 16;
	md5_state_t md5;

	out[32] = '\0';
	md5_init(&md5);
	md5_append(&md5, (unsigned char *)bytes, nbytes);
	md5_finish(&md5, (unsigned char *)digest);
	do {
		*--o = hexchar[*--digestp & 0x0F];
		*--o = hexchar[(*digestp >> 4) & 0x0F];
	} while (o != out);

	return (strdup(out));
}
