/*
 * Copyright (c) 2010 Remko Tronçon
 * Licensed under the GNU General Public License v3.
 * See Documentation/Licenses/GPLv3.txt for more information.
 */

/*
 * This implementation is shamelessly copied from L. Peter Deutsch's
 * implementation, and altered to use our own defines and datastructures.
 * Original license below.
 *//*
	Copyright (C) 1999, 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
 */

#pragma GCC diagnostic ignored "-Wold-style-cast"

#include <Swiften/StringCodecs/MD5.h>

#include <cassert>

#include <Swiften/Base/ByteArray.h>
#include <Swiften/Base/Platform.h>

namespace Swift {

typedef unsigned char md5_byte_t; /* 8-bit byte */
typedef unsigned int md5_word_t; /* 32-bit word */

/* Define the state of the MD5 Algorithm. */
typedef struct md5_state_s {
		md5_word_t count[2];				/* message length in bits, lsw first */
		md5_word_t abcd[4];					/* digest buffer */
		md5_byte_t buf[64];					/* accumulate block */
} md5_state_t;

#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;
#ifdef SWIFTEN_BIG_ENDIAN
		/* 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

		{
#ifdef SWIFTEN_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;
						}
				}
#else
				{
						/*
						 * On big-endian machines, we must arrange the bytes in the
						 * right order.
						 */
						const md5_byte_t *xp = data;
						int i;

						for (i = 0; i < 16; ++i, xp += 4)
								X[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));
}

ByteArray MD5::getHash(const ByteArray& data) {
	ByteArray digest;
	digest.resize(16);

	md5_state_t state;
	md5_init(&state);
	md5_append(&state, reinterpret_cast<const md5_byte_t*>(data.getData()), data.getSize());
	md5_finish(&state, reinterpret_cast<md5_byte_t*>(digest.getData()));

	return digest;
}

}