/* This file is part of the KDE project
   Copyright (C) 2001 George Staikos <staikos@kde.org>
   Based heavily on SHA1 code from GPG 1.0.3 (C) 1998 FSF
 
   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public
   License as published by the Free Software Foundation; either
   version 2 of the License, or (at your option) any later version.
 
   This library 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
   Library General Public License for more details.
 
   You should have received a copy of the GNU Library General Public License
   along with this library; see the file COPYING.LIB.  If not, write to
   the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
   Boston, MA 02110-1301, USA.
*/

#include <config.h>

#ifdef HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#ifdef HAVE_STDINT_H
#include <stdint.h> /* For uintXX_t on OSX */
#endif
#ifdef HAVE_SYS_BITYPES_H
#include <sys/bitypes.h> /* For uintXX_t on Tru64 */
#endif
#ifdef HAVE_STDINT_H
#include <stdint.h>
#endif

#include "sha1.h"
#include <string.h>

// FIXME: this can be optimized to one instruction on most cpus.
#define rol(x,y) ((x << y) | (x >> (32-y)))


#define K1 0x5a827999L
#define K2 0x6ed9eba1L
#define K3 0x8f1bbcdcL
#define K4 0xca62c1d6L
#define F1(x,y,z) ( z ^ ( x & ( y ^ z ) ) )
#define F2(x,y,z) ( x ^ y ^ z )
#define F3(x,y,z) ( ( x & y ) | ( z & ( x | y ) ) )
#define F4(x,y,z) ( x ^ y ^ z )

#define M(i) ( tm = x[i&0x0f] ^ x[(i-14)&0x0f]            \
                  ^ x[(i-8)&0x0f] ^ x[(i-3)&0x0f]         \
                  , (x[i&0x0f] = (tm << 1) | (tm >> 31)))

#define R(a,b,c,d,e,f,k,m)   do { e += rol(a, 5)          \
                                    +  f(b, c, d)         \
                                    +  k                  \
                                    +  m;                 \
                                  b  = rol(b, 30);        \
                                } while(0)


SHA1::SHA1() {
	_hashlen = 160;
	_init = false;
	reset();
}


int SHA1::reset() {
	_h0 = 0x67452301;
	_h1 = 0xefcdab89;
	_h2 = 0x98badcfe;
	_h3 = 0x10325476;
	_h4 = 0xc3d2e1f0;
	_nblocks = 0;
	_count = 0;
	memset(_buf, 0, 56);      // clear the buffer

	_init = true;
	return 0;
}


int SHA1::size() const {
	return _hashlen;
}


SHA1::~SHA1() {

}


void SHA1::transform(void *data) {
	unsigned int a, b, c, d, e, tm;
	unsigned int x[16];
	unsigned char *_data = (unsigned char *)data;

	a = _h0;
	b = _h1;
	c = _h2;
	d = _h3;
	e = _h4;

#ifdef WORDS_BIGENDIAN
	memcpy(x, _data, 64);
#else
	int i;
	unsigned char *p2;
	for (i = 0, p2 = (unsigned char *)x;
			i < 16; i++, p2 += 4) {
		p2[3] = *_data++;
		p2[2] = *_data++;
		p2[1] = *_data++;
		p2[0] = *_data++;
	}
#endif

	R(a, b, c, d, e, F1, K1, x[ 0]);
	R(e, a, b, c, d, F1, K1, x[ 1]);
	R(d, e, a, b, c, F1, K1, x[ 2]);
	R(c, d, e, a, b, F1, K1, x[ 3]);
	R(b, c, d, e, a, F1, K1, x[ 4]);
	R(a, b, c, d, e, F1, K1, x[ 5]);
	R(e, a, b, c, d, F1, K1, x[ 6]);
	R(d, e, a, b, c, F1, K1, x[ 7]);
	R(c, d, e, a, b, F1, K1, x[ 8]);
	R(b, c, d, e, a, F1, K1, x[ 9]);
	R(a, b, c, d, e, F1, K1, x[10]);
	R(e, a, b, c, d, F1, K1, x[11]);
	R(d, e, a, b, c, F1, K1, x[12]);
	R(c, d, e, a, b, F1, K1, x[13]);
	R(b, c, d, e, a, F1, K1, x[14]);
	R(a, b, c, d, e, F1, K1, x[15]);
	R(e, a, b, c, d, F1, K1, M(16));
	R(d, e, a, b, c, F1, K1, M(17));
	R(c, d, e, a, b, F1, K1, M(18));
	R(b, c, d, e, a, F1, K1, M(19));
	R(a, b, c, d, e, F2, K2, M(20));
	R(e, a, b, c, d, F2, K2, M(21));
	R(d, e, a, b, c, F2, K2, M(22));
	R(c, d, e, a, b, F2, K2, M(23));
	R(b, c, d, e, a, F2, K2, M(24));
	R(a, b, c, d, e, F2, K2, M(25));
	R(e, a, b, c, d, F2, K2, M(26));
	R(d, e, a, b, c, F2, K2, M(27));
	R(c, d, e, a, b, F2, K2, M(28));
	R(b, c, d, e, a, F2, K2, M(29));
	R(a, b, c, d, e, F2, K2, M(30));
	R(e, a, b, c, d, F2, K2, M(31));
	R(d, e, a, b, c, F2, K2, M(32));
	R(c, d, e, a, b, F2, K2, M(33));
	R(b, c, d, e, a, F2, K2, M(34));
	R(a, b, c, d, e, F2, K2, M(35));
	R(e, a, b, c, d, F2, K2, M(36));
	R(d, e, a, b, c, F2, K2, M(37));
	R(c, d, e, a, b, F2, K2, M(38));
	R(b, c, d, e, a, F2, K2, M(39));
	R(a, b, c, d, e, F3, K3, M(40));
	R(e, a, b, c, d, F3, K3, M(41));
	R(d, e, a, b, c, F3, K3, M(42));
	R(c, d, e, a, b, F3, K3, M(43));
	R(b, c, d, e, a, F3, K3, M(44));
	R(a, b, c, d, e, F3, K3, M(45));
	R(e, a, b, c, d, F3, K3, M(46));
	R(d, e, a, b, c, F3, K3, M(47));
	R(c, d, e, a, b, F3, K3, M(48));
	R(b, c, d, e, a, F3, K3, M(49));
	R(a, b, c, d, e, F3, K3, M(50));
	R(e, a, b, c, d, F3, K3, M(51));
	R(d, e, a, b, c, F3, K3, M(52));
	R(c, d, e, a, b, F3, K3, M(53));
	R(b, c, d, e, a, F3, K3, M(54));
	R(a, b, c, d, e, F3, K3, M(55));
	R(e, a, b, c, d, F3, K3, M(56));
	R(d, e, a, b, c, F3, K3, M(57));
	R(c, d, e, a, b, F3, K3, M(58));
	R(b, c, d, e, a, F3, K3, M(59));
	R(a, b, c, d, e, F4, K4, M(60));
	R(e, a, b, c, d, F4, K4, M(61));
	R(d, e, a, b, c, F4, K4, M(62));
	R(c, d, e, a, b, F4, K4, M(63));
	R(b, c, d, e, a, F4, K4, M(64));
	R(a, b, c, d, e, F4, K4, M(65));
	R(e, a, b, c, d, F4, K4, M(66));
	R(d, e, a, b, c, F4, K4, M(67));
	R(c, d, e, a, b, F4, K4, M(68));
	R(b, c, d, e, a, F4, K4, M(69));
	R(a, b, c, d, e, F4, K4, M(70));
	R(e, a, b, c, d, F4, K4, M(71));
	R(d, e, a, b, c, F4, K4, M(72));
	R(c, d, e, a, b, F4, K4, M(73));
	R(b, c, d, e, a, F4, K4, M(74));
	R(a, b, c, d, e, F4, K4, M(75));
	R(e, a, b, c, d, F4, K4, M(76));
	R(d, e, a, b, c, F4, K4, M(77));
	R(c, d, e, a, b, F4, K4, M(78));
	R(b, c, d, e, a, F4, K4, M(79));

	_h0 += a;
	_h1 += b;
	_h2 += c;
	_h3 += d;
	_h4 += e;

}


bool SHA1::readyToGo() const {
	return _init;
}


int SHA1::process(const void *block, int len) {
	if (!_init) {
		return -1;
	}

	unsigned char *_block = (unsigned char *)block;

	int cnt = 0;
	// Flush the buffer before proceeding
	if (_count == 64) {
		transform(_buf);
		_count = 0;
		_nblocks++;
	}

	if (!_block) {
		return 0;
	}

	if (_count) {
		for (; len && _count < 64; len--, cnt++) {
			_buf[_count++] = *_block++;
		}
		process(0, 0);       // flush the buffer if necessary
		if (!len) {
			return cnt;
		}
	}

	while (len >= 64) {
		transform(_block);
		_count = 0;
		_nblocks++;
		len -= 64;
		cnt += 64;
		_block += 64;
	}

	for (; len && _count < 64; len--, cnt++) {
		_buf[_count++] = *_block++;
	}

	return cnt;
}


const unsigned char *SHA1::hash() {
	unsigned int t, msb, lsb;
	unsigned char *p;


	if (!_init) {
		return (unsigned char *)_buf;
	}

	process(0, 0);

	msb = 0;
	t = _nblocks;

	if ((lsb = t << 6) < t) {
		msb++;
	}

	msb += t >> 26;
	t = lsb;

	if ((lsb = t + _count) < t) {
		msb++;
	}

	t = lsb;

	if ((lsb = t << 3) < t) {
		msb++;
	}

	msb += t >> 29;

	_buf[_count++] = 0x80;

	if (_count < 56) {
		while (_count < 56) {
			_buf[_count++] = 0;
		}
	} else {
		while (_count < 64) {
			_buf[_count++] = 0;
		}
		process(0, 0);
		memset(_buf, 0, 56);
	}

	_buf[56] = msb >> 24;
	_buf[57] = msb >> 16;
	_buf[58] = msb >>  8;
	_buf[59] = msb;
	_buf[60] = lsb >> 24;
	_buf[61] = lsb >> 16;
	_buf[62] = lsb >>  8;
	_buf[63] = lsb;

	transform(_buf);

	p = _buf;

#ifdef WORDS_BIGENDIAN
#define X( a ) do { *( uint32_t * )p = _h##a; p += 4; } while ( 0 )
#else
#define X(a) do { *p++ = _h##a >> 24;  *p++ = _h##a >> 16;             \
			*p++ = _h##a >>  8;  *p++ = _h##a;        } while (0)
#endif

		X(0);
	X(1);
	X(2);
	X(3);
	X(4);

#undef X

	_init = false;

	return (unsigned char *)_buf;
}