
/*
Christophe Devine
c.devine@cr0.net
http://www.cr0.net:8040/code/crypto/
*/
/*
 *  RFC 1321 compliant MD5 implementation
 *
 *  Copyright (C) 2001-2003  Christophe Devine
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

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


#define GET_UINT32(n,b,i)                       \
{                                               \
    (n) = ( (uint32) (b)[(i)    ]       )       \
        | ( (uint32) (b)[(i) + 1] <<  8 )       \
        | ( (uint32) (b)[(i) + 2] << 16 )       \
        | ( (uint32) (b)[(i) + 3] << 24 );      \
}

#define PUT_UINT32(n,b,i)                       \
{                                               \
    (b)[(i)    ] = (uint8) ( (n)       );       \
    (b)[(i) + 1] = (uint8) ( (n) >>  8 );       \
    (b)[(i) + 2] = (uint8) ( (n) >> 16 );       \
    (b)[(i) + 3] = (uint8) ( (n) >> 24 );       \
}

void md5_starts( md5_context *ctx )
{
	ctx->total[0] = 0;
	ctx->total[1] = 0;

	ctx->state[0] = 0x67452301;
	ctx->state[1] = 0xEFCDAB89;
	ctx->state[2] = 0x98BADCFE;
	ctx->state[3] = 0x10325476;
}

void md5_process( md5_context *ctx, uint8 data[64] )
{
	uint32 X[16], A, B, C, D;

	GET_UINT32( X[0], data, 0 );
	GET_UINT32( X[1], data, 4 );
	GET_UINT32( X[2], data, 8 );
	GET_UINT32( X[3], data, 12 );
	GET_UINT32( X[4], data, 16 );
	GET_UINT32( X[5], data, 20 );
	GET_UINT32( X[6], data, 24 );
	GET_UINT32( X[7], data, 28 );
	GET_UINT32( X[8], data, 32 );
	GET_UINT32( X[9], data, 36 );
	GET_UINT32( X[10], data, 40 );
	GET_UINT32( X[11], data, 44 );
	GET_UINT32( X[12], data, 48 );
	GET_UINT32( X[13], data, 52 );
	GET_UINT32( X[14], data, 56 );
	GET_UINT32( X[15], data, 60 );

#define S(x,n) ((x << n) | ((x & 0xFFFFFFFF) >> (32 - n)))

#define P(a,b,c,d,k,s,t)                                \
	{                                                       \
    a += F(b,c,d) + X[k] + t; a = S(a,s) + b;           \
	}

	A = ctx->state[0];
	B = ctx->state[1];
	C = ctx->state[2];
	D = ctx->state[3];

#define F(x,y,z) (z ^ (x & (y ^ z)))

	P( A, B, C, D, 0, 7, 0xD76AA478 );
	P( D, A, B, C, 1, 12, 0xE8C7B756 );
	P( C, D, A, B, 2, 17, 0x242070DB );
	P( B, C, D, A, 3, 22, 0xC1BDCEEE );
	P( A, B, C, D, 4, 7, 0xF57C0FAF );
	P( D, A, B, C, 5, 12, 0x4787C62A );
	P( C, D, A, B, 6, 17, 0xA8304613 );
	P( B, C, D, A, 7, 22, 0xFD469501 );
	P( A, B, C, D, 8, 7, 0x698098D8 );
	P( D, A, B, C, 9, 12, 0x8B44F7AF );
	P( C, D, A, B, 10, 17, 0xFFFF5BB1 );
	P( B, C, D, A, 11, 22, 0x895CD7BE );
	P( A, B, C, D, 12, 7, 0x6B901122 );
	P( D, A, B, C, 13, 12, 0xFD987193 );
	P( C, D, A, B, 14, 17, 0xA679438E );
	P( B, C, D, A, 15, 22, 0x49B40821 );

#undef F

#define F(x,y,z) (y ^ (z & (x ^ y)))

	P( A, B, C, D, 1, 5, 0xF61E2562 );
	P( D, A, B, C, 6, 9, 0xC040B340 );
	P( C, D, A, B, 11, 14, 0x265E5A51 );
	P( B, C, D, A, 0, 20, 0xE9B6C7AA );
	P( A, B, C, D, 5, 5, 0xD62F105D );
	P( D, A, B, C, 10, 9, 0x02441453 );
	P( C, D, A, B, 15, 14, 0xD8A1E681 );
	P( B, C, D, A, 4, 20, 0xE7D3FBC8 );
	P( A, B, C, D, 9, 5, 0x21E1CDE6 );
	P( D, A, B, C, 14, 9, 0xC33707D6 );
	P( C, D, A, B, 3, 14, 0xF4D50D87 );
	P( B, C, D, A, 8, 20, 0x455A14ED );
	P( A, B, C, D, 13, 5, 0xA9E3E905 );
	P( D, A, B, C, 2, 9, 0xFCEFA3F8 );
	P( C, D, A, B, 7, 14, 0x676F02D9 );
	P( B, C, D, A, 12, 20, 0x8D2A4C8A );

#undef F

#define F(x,y,z) (x ^ y ^ z)

	P( A, B, C, D, 5, 4, 0xFFFA3942 );
	P( D, A, B, C, 8, 11, 0x8771F681 );
	P( C, D, A, B, 11, 16, 0x6D9D6122 );
	P( B, C, D, A, 14, 23, 0xFDE5380C );
	P( A, B, C, D, 1, 4, 0xA4BEEA44 );
	P( D, A, B, C, 4, 11, 0x4BDECFA9 );
	P( C, D, A, B, 7, 16, 0xF6BB4B60 );
	P( B, C, D, A, 10, 23, 0xBEBFBC70 );
	P( A, B, C, D, 13, 4, 0x289B7EC6 );
	P( D, A, B, C, 0, 11, 0xEAA127FA );
	P( C, D, A, B, 3, 16, 0xD4EF3085 );
	P( B, C, D, A, 6, 23, 0x04881D05 );
	P( A, B, C, D, 9, 4, 0xD9D4D039 );
	P( D, A, B, C, 12, 11, 0xE6DB99E5 );
	P( C, D, A, B, 15, 16, 0x1FA27CF8 );
	P( B, C, D, A, 2, 23, 0xC4AC5665 );

#undef F

#define F(x,y,z) (y ^ (x | ~z))

	P( A, B, C, D, 0, 6, 0xF4292244 );
	P( D, A, B, C, 7, 10, 0x432AFF97 );
	P( C, D, A, B, 14, 15, 0xAB9423A7 );
	P( B, C, D, A, 5, 21, 0xFC93A039 );
	P( A, B, C, D, 12, 6, 0x655B59C3 );
	P( D, A, B, C, 3, 10, 0x8F0CCC92 );
	P( C, D, A, B, 10, 15, 0xFFEFF47D );
	P( B, C, D, A, 1, 21, 0x85845DD1 );
	P( A, B, C, D, 8, 6, 0x6FA87E4F );
	P( D, A, B, C, 15, 10, 0xFE2CE6E0 );
	P( C, D, A, B, 6, 15, 0xA3014314 );
	P( B, C, D, A, 13, 21, 0x4E0811A1 );
	P( A, B, C, D, 4, 6, 0xF7537E82 );
	P( D, A, B, C, 11, 10, 0xBD3AF235 );
	P( C, D, A, B, 2, 15, 0x2AD7D2BB );
	P( B, C, D, A, 9, 21, 0xEB86D391 );

#undef F

	ctx->state[0] += A;
	ctx->state[1] += B;
	ctx->state[2] += C;
	ctx->state[3] += D;
}

void md5_update( md5_context *ctx, uint8 *input, uint32 length )
{
	uint32 left, fill;

	if (!length) return;

	left = ctx->total[0] & 0x3F;
	fill = 64 - left;

	ctx->total[0] += length;
	ctx->total[0] &= 0xFFFFFFFF;

	if (ctx->total[0] < length)
		ctx->total[1]++;

	if (left && length >= fill)
	{
		memcpy( (void *)(ctx->buffer + left),
				(void *)input, fill );
		md5_process( ctx, ctx->buffer );
		length -= fill;
		input += fill;
		left = 0;
	}

	while (length >= 64)
	{
		md5_process( ctx, input );
		length -= 64;
		input += 64;
	}

	if (length)
	{
		memcpy( (void *)(ctx->buffer + left),
				(void *)input, length );
	}
}

static uint8 md5_padding[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
};

void md5_finish( md5_context *ctx, uint8 digest[16] )
{
	uint32 last, padn;
	uint32 high, low;
	uint8 msglen[8];

	high = (ctx->total[0] >> 29)
		| (ctx->total[1] << 3);
	low = (ctx->total[0] << 3);

	PUT_UINT32( low, msglen, 0 );
	PUT_UINT32( high, msglen, 4 );

	last = ctx->total[0] & 0x3F;
	padn = (last < 56) ? (56 - last) : (120 - last);

	md5_update( ctx, md5_padding, padn );
	md5_update( ctx, msglen, 8 );

	PUT_UINT32( ctx->state[0], digest, 0 );
	PUT_UINT32( ctx->state[1], digest, 4 );
	PUT_UINT32( ctx->state[2], digest, 8 );
	PUT_UINT32( ctx->state[3], digest, 12 );
}
