#include "precomp.h"
#include "sha1.h"

#define MAX_FILE_READ_BUFFER 8000

// Rotate x bits to the left
#ifndef ROL32
#define ROL32(_val32, _nBits) (((_val32)<<(_nBits))|((_val32)>>(32-(_nBits))))
#endif

#ifdef SHA1_LITTLE_ENDIAN
	#define SHABLK0(i) (m_block->l[i] = \
		(ROL32(m_block->l[i],24) & 0xFF00FF00) | (ROL32(m_block->l[i],8) & 0x00FF00FF))
#else
	#define SHABLK0(i) (m_block->l[i])
#endif

#define SHABLK(i) (m_block->l[i&15] = ROL32(m_block->l[(i+13)&15] ^ m_block->l[(i+8)&15] \
	^ m_block->l[(i+2)&15] ^ m_block->l[i&15],1))

// SHA-1 rounds
#define _R0(v,w,x,y,z,i) { z+=((w&(x^y))^y)+SHABLK0(i)+0x5A827999+ROL32(v,5); w=ROL32(w,30); }
#define _R1(v,w,x,y,z,i) { z+=((w&(x^y))^y)+SHABLK(i)+0x5A827999+ROL32(v,5); w=ROL32(w,30); }
#define _R2(v,w,x,y,z,i) { z+=(w^x^y)+SHABLK(i)+0x6ED9EBA1+ROL32(v,5); w=ROL32(w,30); }
#define _R3(v,w,x,y,z,i) { z+=(((w|x)&y)|(w&x))+SHABLK(i)+0x8F1BBCDC+ROL32(v,5); w=ROL32(w,30); }
#define _R4(v,w,x,y,z,i) { z+=(w^x^y)+SHABLK(i)+0xCA62C1D6+ROL32(v,5); w=ROL32(w,30); }

SHA1::SHA1()
{
	m_block = (SHA1_WORKSPACE_BLOCK *)m_workspace;

	Reset();
}

SHA1::~SHA1()
{
	Reset();
}

void SHA1::Reset()
{
	// SHA1 initialization constants
	m_state[0] = 0x67452301;
	m_state[1] = 0xEFCDAB89;
	m_state[2] = 0x98BADCFE;
	m_state[3] = 0x10325476;
	m_state[4] = 0xC3D2E1F0;

	m_count[0] = 0;
	m_count[1] = 0;
}

void SHA1::Transform(unsigned int state[5], unsigned char buffer[64])
{
	unsigned int a = 0, b = 0, c = 0, d = 0, e = 0;

	memcpy(m_block, buffer, 64);

	// Copy 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 state[]
	state[0] += a;
	state[1] += b;
	state[2] += c;
	state[3] += d;
	state[4] += e;

	// Wipe variables
	a = b = c = d = e = 0;
}

// Use this function to hash in binary data and strings
void SHA1::Update(unsigned char *data, unsigned int len)
{
	unsigned int i = 0, j;

	j = (m_count[0] >> 3) & 63;

	if((m_count[0] += len << 3) < (len << 3)) m_count[1]++;

	m_count[1] += (len >> 29);

	if((j + len) > 63)
	{
		memcpy(&m_buffer[j], data, (i = 64 - j));
		Transform(m_state, m_buffer);

		for (; i+63 < len; i += 64)
			Transform(m_state, &data[i]);

		j = 0;
	}
	else i = 0;

	memcpy(&m_buffer[j], &data[i], len - i);
}

void SHA1::Final()
{
	unsigned int i = 0;
	unsigned char finalcount[8] = { 0, 0, 0, 0, 0, 0, 0, 0 };

	for (i = 0; i < 8; i++)
		finalcount[i] = (unsigned char)((m_count[(i >= 4 ? 0 : 1)]
			>> ((3 - (i & 3)) * 8) ) & 255); // Endian independent

	Update((unsigned char *)"\200", 1);

	while ((m_count[0] & 504) != 448)
		Update((unsigned char *)"\0", 1);

	Update(finalcount, 8); // Cause a SHA1Transform()

	for (i = 0; i < 20; i++)
	{
		m_digest[i] = (unsigned char)((m_state[i >> 2] >> ((3 - (i & 3)) * 8) ) & 255);
	}

	// Wipe variables for security reasons
	i = 0;
	memset(m_buffer, 0, 64);
	memset(m_state, 0, 20);
	memset(m_count, 0, 8);
	memset(finalcount, 0, 8);

	Transform(m_state, m_buffer);
}

// Get the raw message digest
void SHA1::GetHash(unsigned char *uDest)
{
	memcpy(uDest, m_digest, 20);
}