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

#include <Swiften/StringCodecs/SHA1.h>

#include "Swiften/Base/Platform.h"

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

using namespace Swift;

/*
SHA-1 in C
By Steve Reid <steve@edmweb.com>
100% Public Domain

Test Vectors (from FIPS PUB 180-1)
"abc"
	A9993E36 4706816A BA3E2571 7850C26C 9CD0D89D
"abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq"
	84983E44 1C3BD26E BAAE4AA1 F95129E5 E54670F1
A million repetitions of "a"
	34AA973C D4C4DAA4 F61EEB2B DBAD2731 6534016F
*/

/* #define LITTLE_ENDIAN * This should be #define'd if true. */
/* #define SHA1HANDSOFF * Copies data before messing with it. */

#include <stdio.h>
#include <string.h>

#define rol(value, bits) (((value) << (bits)) | ((value) >> (32 - (bits))))

/* blk0() and blk() perform the initial expand. */
/* I got the idea of expanding during the round function from SSLeay */
#ifdef SWIFTEN_LITTLE_ENDIAN
#define blk0(i) (block->l[i] = (rol(block->l[i],24)&0xFF00FF00) \
		|(rol(block->l[i],8)&0x00FF00FF))
#else
#define blk0(i) block->l[i]
#endif
#define blk(i) (block->l[i&15] = rol(block->l[(i+13)&15]^block->l[(i+8)&15] \
		^block->l[(i+2)&15]^block->l[i&15],1))

/* (R0+R1), R2, R3, R4 are the different operations used in SHA1 */
#define R0(v,w,x,y,z,i) z+=((w&(x^y))^y)+blk0(i)+0x5A827999+rol(v,5);w=rol(w,30);
#define R1(v,w,x,y,z,i) z+=((w&(x^y))^y)+blk(i)+0x5A827999+rol(v,5);w=rol(w,30);
#define R2(v,w,x,y,z,i) z+=(w^x^y)+blk(i)+0x6ED9EBA1+rol(v,5);w=rol(w,30);
#define R3(v,w,x,y,z,i) z+=(((w|x)&y)|(w&x))+blk(i)+0x8F1BBCDC+rol(v,5);w=rol(w,30);
#define R4(v,w,x,y,z,i) z+=(w^x^y)+blk(i)+0xCA62C1D6+rol(v,5);w=rol(w,30);


/* Hash a single 512-bit block. This is the core of the algorithm. */

void SHA1::Transform(boost::uint32_t state[5], boost::uint8_t buffer[64])
{
boost::uint32_t a, b, c, d, e;
typedef union {
		boost::uint8_t c[64];
		boost::uint32_t l[16];
} CHAR64LONG16;
CHAR64LONG16* block;
#ifdef SHA1HANDSOFF
static boost::uint8_t workspace[64];
		block = (CHAR64LONG16*)workspace;
		memcpy(block, buffer, 64);
#else
		block = reinterpret_cast<CHAR64LONG16*>(buffer);
#endif
		/* Copy context->state[] to working vars */
		a = state[0];
		b = state[1];
		c = state[2];
		d = state[3];
		e = state[4];
		/* 4 rounds of 20 operations each. Loop unrolled. */
		R0(a,b,c,d,e, 0); R0(e,a,b,c,d, 1); R0(d,e,a,b,c, 2); R0(c,d,e,a,b, 3);
		R0(b,c,d,e,a, 4); R0(a,b,c,d,e, 5); R0(e,a,b,c,d, 6); R0(d,e,a,b,c, 7);
		R0(c,d,e,a,b, 8); R0(b,c,d,e,a, 9); R0(a,b,c,d,e,10); R0(e,a,b,c,d,11);
		R0(d,e,a,b,c,12); R0(c,d,e,a,b,13); R0(b,c,d,e,a,14); R0(a,b,c,d,e,15);
		R1(e,a,b,c,d,16); R1(d,e,a,b,c,17); R1(c,d,e,a,b,18); R1(b,c,d,e,a,19);
		R2(a,b,c,d,e,20); R2(e,a,b,c,d,21); R2(d,e,a,b,c,22); R2(c,d,e,a,b,23);
		R2(b,c,d,e,a,24); R2(a,b,c,d,e,25); R2(e,a,b,c,d,26); R2(d,e,a,b,c,27);
		R2(c,d,e,a,b,28); R2(b,c,d,e,a,29); R2(a,b,c,d,e,30); R2(e,a,b,c,d,31);
		R2(d,e,a,b,c,32); R2(c,d,e,a,b,33); R2(b,c,d,e,a,34); R2(a,b,c,d,e,35);
		R2(e,a,b,c,d,36); R2(d,e,a,b,c,37); R2(c,d,e,a,b,38); R2(b,c,d,e,a,39);
		R3(a,b,c,d,e,40); R3(e,a,b,c,d,41); R3(d,e,a,b,c,42); R3(c,d,e,a,b,43);
		R3(b,c,d,e,a,44); R3(a,b,c,d,e,45); R3(e,a,b,c,d,46); R3(d,e,a,b,c,47);
		R3(c,d,e,a,b,48); R3(b,c,d,e,a,49); R3(a,b,c,d,e,50); R3(e,a,b,c,d,51);
		R3(d,e,a,b,c,52); R3(c,d,e,a,b,53); R3(b,c,d,e,a,54); R3(a,b,c,d,e,55);
		R3(e,a,b,c,d,56); R3(d,e,a,b,c,57); R3(c,d,e,a,b,58); R3(b,c,d,e,a,59);
		R4(a,b,c,d,e,60); R4(e,a,b,c,d,61); R4(d,e,a,b,c,62); R4(c,d,e,a,b,63);
		R4(b,c,d,e,a,64); R4(a,b,c,d,e,65); R4(e,a,b,c,d,66); R4(d,e,a,b,c,67);
		R4(c,d,e,a,b,68); R4(b,c,d,e,a,69); R4(a,b,c,d,e,70); R4(e,a,b,c,d,71);
		R4(d,e,a,b,c,72); R4(c,d,e,a,b,73); R4(b,c,d,e,a,74); R4(a,b,c,d,e,75);
		R4(e,a,b,c,d,76); R4(d,e,a,b,c,77); R4(c,d,e,a,b,78); R4(b,c,d,e,a,79);
		/* Add the working vars back into context.state[] */
		state[0] += a;
		state[1] += b;
		state[2] += c;
		state[3] += d;
		state[4] += e;
		/* Wipe variables */
		a = b = c = d = e = 0;
}


/* SHA1Init - Initialize new context */

void SHA1::Init(SHA1::CTX* context)
{
		/* SHA1 initialization constants */
		context->state[0] = 0x67452301;
		context->state[1] = 0xEFCDAB89;
		context->state[2] = 0x98BADCFE;
		context->state[3] = 0x10325476;
		context->state[4] = 0xC3D2E1F0;
		context->count[0] = context->count[1] = 0;
}


/* Run your data through this. */

void SHA1::Update(SHA1::CTX* context, boost::uint8_t* data, unsigned int len)
{
unsigned int i, j;

		j = (context->count[0] >> 3) & 63;
		if ((context->count[0] += len << 3) < (len << 3)) context->count[1]++;
		context->count[1] += (len >> 29);
		if ((j + len) > 63) {
				memcpy(&context->buffer[j], data, (i = 64-j));
				Transform(context->state, context->buffer);
				for ( ; i + 63 < len; i += 64) {
						Transform(context->state, &data[i]);
				}
				j = 0;
		}
		else i = 0;
		memcpy(&context->buffer[j], &data[i], len - i);
}


/* Add padding and return the message digest. */

void SHA1::Final(boost::uint8_t digest[20], SHA1::CTX* context)
{
boost::uint32_t i, j;
boost::uint8_t finalcount[8];

		for (i = 0; i < 8; i++) {
				finalcount[i] = (boost::uint8_t) ((context->count[(i >= 4 ? 0 : 1)]
				 >> ((3-(i & 3)) * 8) ) & 255);  /* Endian independent */
		}
		Update(context, (boost::uint8_t *)("\200"), 1);
		while ((context->count[0] & 504) != 448) {
				Update(context, (boost::uint8_t *)("\0"), 1);
		}
		Update(context, finalcount, 8);  /* Should cause a SHA1Transform() */
		for (i = 0; i < 20; i++) {
				digest[i] = (boost::uint8_t)
				 ((context->state[i>>2] >> ((3-(i & 3)) * 8) ) & 255);
		}
		/* Wipe variables */
		i = j = 0;
		memset(context->buffer, 0, 64);
		memset(context->state, 0, 20);
		memset(context->count, 0, 8);
		memset(&finalcount, 0, 8);
#ifdef SHA1HANDSOFF  /* make SHA1Transform overwrite it's own static vars */
		Transform(context->state, context->buffer);
#endif
}

// -----------------------------------------------------------------------------

namespace Swift {

SHA1::SHA1() {
	Init(&context);
}

SHA1& SHA1::update(const std::vector<unsigned char>& input) {
	std::vector<unsigned char> inputCopy(input);
	Update(&context, (boost::uint8_t*) &inputCopy[0], inputCopy.size());
	return *this;
}

std::vector<unsigned char> SHA1::getHash() const {
	std::vector<unsigned char> digest;
	digest.resize(20);
	CTX contextCopy(context);
	Final((boost::uint8_t*) &digest[0], &contextCopy);
	return digest;
}

ByteArray SHA1::getHash(const ByteArray& input) {
	CTX context;
	Init(&context);

	std::vector<unsigned char> inputCopy(input.getVector());
	Update(&context, (boost::uint8_t*) &inputCopy[0], inputCopy.size());

	ByteArray digest;
	digest.resize(20);
	Final((boost::uint8_t*) digest.getData(), &context);

	return digest;
}

}