/**
* @brief SHA-1 Hash key computation
*
* 100% free public domain implementation of the SHA-1
* algorithm by Dominik Reichl <Dominik.Reichl@tiscali.de>
*
*
* === 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
*/


#include "SHA1.h"
#include <stdlib.h>


CSHA1::CSHA1()
{
	Reset();
}

CSHA1::~CSHA1()
{
	Reset();
}


void CSHA1::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 CSHA1::Transform( unsigned int state[ 5 ], unsigned char buffer[ 64 ] )
{
	unsigned int a = 0, b = 0, c = 0, d = 0, e = 0;

	SHA1_WORKSPACE_BLOCK* block;
	// static unsigned char workspace[64];
	block = ( SHA1_WORKSPACE_BLOCK * ) workspace;
	memcpy( 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 = 0;
	b = 0;
	c = 0;
	d = 0;
	e = 0;
}

// Use this function to hash in binary data and strings
void CSHA1::Update( unsigned char* data, unsigned int len )
{
	unsigned int i = 0, j = 0;

	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 );
}

// Hash in file contents
bool CSHA1::HashFile( char *szFileName )
{
	unsigned long ulFileSize = 0, ulRest = 0, ulBlocks = 0;
	unsigned long i = 0;
	unsigned char uData[ MAX_FILE_READ_BUFFER ];
	FILE *fIn = NULL;

	if ( ( fIn = fopen( szFileName, "rb" ) ) == NULL )
		return ( false );

	fseek( fIn, 0, SEEK_END );

	ulFileSize = ftell( fIn );

	fseek( fIn, 0, SEEK_SET );

	// This is faster
	div_t temp;

	temp = div( ulFileSize, MAX_FILE_READ_BUFFER );

	ulRest = temp.rem;

	ulBlocks = temp.quot;

	// ulRest = ulFileSize % MAX_FILE_READ_BUFFER;
	// ulBlocks = ulFileSize / MAX_FILE_READ_BUFFER;

	for ( i = 0; i < ulBlocks; i++ )
	{
		fread( uData, 1, MAX_FILE_READ_BUFFER, fIn );
		Update( uData, MAX_FILE_READ_BUFFER );
	}

	if ( ulRest != 0 )
	{
		fread( uData, 1, ulRest, fIn );
		Update( uData, ulRest );
	}

	fclose( fIn );
	fIn = NULL;

	return ( true );
}

void CSHA1::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;

//		j = 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 final hash as a pre-formatted string
void CSHA1::ReportHash( char *szReport, unsigned char uReportType )
{
	unsigned char i = 0;
	char szTemp[ 4 ];

	if ( uReportType == REPORT_HEX )
	{
		sprintf( szTemp, "%02X", m_digest[ 0 ] );
		strcat( szReport, szTemp );

		for ( i = 1; i < 20; i++ )
		{
			sprintf( szTemp, " %02X", m_digest[ i ] );
			strcat( szReport, szTemp );
		}
	}

	else
		if ( uReportType == REPORT_DIGIT )
		{
			sprintf( szTemp, "%u", m_digest[ 0 ] );
			strcat( szReport, szTemp );

			for ( i = 1; i < 20; i++ )
			{
				sprintf( szTemp, " %u", m_digest[ i ] );
				strcat( szReport, szTemp );
			}
		}

		else
			strcpy( szReport, "Error: Unknown report type!" );
}

// Get the raw message digest
void CSHA1::GetHash( unsigned char *uDest )
{
	memcpy( uDest, m_digest, 20 );
}

// Get the raw message digest
// Added by Kevin to be quicker
unsigned char * CSHA1::GetHash( void ) const
{
	return ( unsigned char * ) m_digest;
}
