42_INT_09_piscine_cpp/d02/ex02/Fixed.cpp

#include "Fixed.hpp"

/*
 * functions to print numbers in binary
 * for the float, found help from stackoverflow :
 * https://stackoverflow.com/questions/474007/floating-point-to-binary-valuec
 */

std::string printBitsInt(int num)
{
	int i = 0;

	for (unsigned int mask = 1U << (sizeof(int) *8 -1); mask; mask >>= 1)
	{
		std::cout << ((num & mask) != 0);
		i++;
		if (i == 1 || i == 9 || i == 24)
			std::cout << ' ';
	}
	return "";
}

std::string	printBitsFloat(float num)
{
	int	*p = (int *)&num;
	int i = 0;

	for (unsigned int mask = 1U << (sizeof(float) *8 -1); mask; mask >>= 1)
	{
		std::cout << ((*p & mask) != 0);
		i++;
		if (i == 1 || i == 9 || i == 24)
			std::cout << ' ';
	}
	return "";
}


/*
 * statics variables initialisation
 *
 * for MAX integer :
 * 00000000 01111111 11111111 11111111 ( 8388607) (-1U >> (this->_frac +1))
 *              <= ... >=
 * 11111111 10000000 00000000 00000000 (-8388608)
 *
 */

int const Fixed::_frac = 8;
int const Fixed::_max = -1U >> (_frac +1);


/*
 * default constructor / copy constructor / destructor
 */

Fixed::Fixed() : _value(0) {
	return;
}

Fixed::Fixed(Fixed const & src) {
	*this = src;
	return;
}

Fixed::~Fixed( void ) {
	return;
}


/*
 * int and float constructors
 */

Fixed::Fixed(int integer) {
	if (integer < ~this->_max || integer > this->_max)
		std::cout << "error: integer out of range" << '\n';
	else
		this->_value = integer << this->_frac;
}

Fixed::Fixed(float const floater) {
	if (floater < ~this->_max || floater > this->_max)
		std::cout << "error: float out of range" << '\n';
	else
		this->_value = roundf(floater * (1 << this->_frac));
}


/*
 * assignement operator
 */

Fixed &	Fixed::operator=( Fixed const & rhs ) {
	if ( this != &rhs )
		this->_value = rhs.getRawBits();
	return *this;
}


/*
 * operators < ; > ; <= ; == ; != ; + ; - ; * ; / ; ++ ; --
 * ref : https://en.cppreference.com/w/cpp/language/operators
 * for division, if you want to avoid floats (legitimate) :
 * https://stackoverflow.com/questions/8506317/fixed-point-unsigned-division-in-c
 */

bool	Fixed::operator< (Fixed const & rhs) const {
	return this->toFloat() < rhs.toFloat();
}
bool	Fixed::operator> (Fixed const & rhs) const {
	return this->toFloat() > rhs.toFloat();
}
bool	Fixed::operator<=(Fixed const & rhs) const {
	return this->toFloat() <= rhs.toFloat();
}
bool	Fixed::operator>=(Fixed const & rhs) const {
	return this->toFloat() >= rhs.toFloat();
}
bool	Fixed::operator==(Fixed const & rhs) const {
	return this->toFloat() == rhs.toFloat();
}
bool	Fixed::operator!=(Fixed const & rhs) const {
	return this->toFloat() != rhs.toFloat();
}
Fixed	Fixed::operator+ ( Fixed const & rhs ) const {
	Fixed	result(*this);
	result._value += rhs._value;
	return (result);
}
Fixed	Fixed::operator- ( Fixed const & rhs ) const {
	Fixed	result(*this);
	result._value -= rhs._value;
	return (result);
}
Fixed	Fixed::operator* ( Fixed const & rhs ) const {
	Fixed	result(*this);
	int		left = this->_value;
	int		right = rhs._value;

	result._value = 0;
													// left:5 right:10
	while (right > 0)								//           1
	{
		result._value /= 10;						//    0/10 = 0     0/10 = 0
		result._value += (left * (right % 10));		// 0+(5*0) = 0  0+(5*1) = 1
std::cout << "intermediaire: " << result << " ";	//
		right /= 10;								//   10/10 = 1     1/10 = 0
	}
	result._value >>= _frac;

//	result._value *= rhs._value >> _frac;
//	result._value += (this->_value * (rhs._value & ((1 << (_frac + 1)) - 1))) >> _frac;

//	result._value = ((long)result._value * (long)rhs._value) >> 8;

	return result;

//
// 47 * 256 = 12 032
// 5 * 10 -> 5*256 * 10*256 -> 5 * 10 * 256^2
// 256^2 = 65 536
//    256 :          1 00000000
// 65 536 : 1 00000000 00000000
//
//
//   5 *   10 = 50
// 101 * 1010 = 110010
// 101.00000000 * 1010.00000000 = 110010.00000000
// 101 00000000 * 1010 00000000 = 110010 00000000
//                                110010 00000000
//          128 *          2560 =          327680
//
//
//  3 *   5 =   15
// 11 * 101 = 1111
//
//
//  3.5 *   5.25 =    18.375
// 11.1 * 101.01 = 10010.011
// 11 1 * 101 01 = 10010 011
//    7 *     21 =       147
//
//
//   3.5 * 5.25
//   3.5 * (5 + 0.25)
//   3.5 * 5
// + 3.5 * 0.25
//
// 3.5 * 4.25 = 14.875
// 3.5 * (0.05 + 0.20 + 4.00)
// 3.5 * 0.05 = 0.175 = 17.5 / 100
// 3.5 * 0.20 = 0.7 = 7 / 10
// 3.5 * 4.00 = 14
// 14 + 0.7 + 0.175 = 14.875
//
// 3.5 * 5 = 17.5
// 3.5 * 2 = 7
// 3.5 * 4 = 14
// (((17.5 / 10) + 7) / 10) + 14
//    17.5 / 10
//         1.75  + 7
//              8.75  / 10
//                   0.875  + 14
//

}
Fixed	Fixed::operator/ ( Fixed const & rhs ) const {
	std::cout << this->_value << " " << rhs._value << " "
			  << (( (this->_value << 8) / rhs._value )) << "\n";
	return Fixed( this->toFloat() / rhs.toFloat() );
}
Fixed	Fixed::operator++() {
	this->_value++;
	return *this;
}
Fixed	Fixed::operator--() {
	this->_value--;
	return *this;
}
Fixed	Fixed::operator++( int ) {
	Fixed old = *this;
	Fixed::operator++();
	return old;
}
Fixed	Fixed::operator--( int ) {
	Fixed old = *this;
	Fixed::operator--();
	return old;
}


/*
 * returns min and max
 */

Fixed const &	Fixed::min(Fixed const & lhs, Fixed const & rhs) {
	if (lhs < rhs)
		return lhs;
	return rhs;
}
Fixed const &	Fixed::max(Fixed const & lhs, Fixed const & rhs) {
	if (lhs > rhs)
		return lhs;
	return rhs;
}
Fixed &	Fixed::min(Fixed & lhs, Fixed & rhs) {
	if (lhs < rhs)
		return lhs;
	return rhs;
}
Fixed &	Fixed::max(Fixed & lhs, Fixed & rhs) {
	if (lhs > rhs)
		return lhs;
	return rhs;
}


/*
 * functions that returns _value
 */

int		Fixed::getRawBits( void ) const {
	return this->_value;
}

void	Fixed::setRawBits( int const raw ) {
	this->_value = raw;
}

int		Fixed::toInt( void ) const {
	return (this->_value >> this->_frac);
}
float	Fixed::toFloat( void ) const {
	return ((float)this->_value / (float)(1 << this->_frac));
}


/*
 * overload "<<" -> output fixed point in float representation
 * found here : https://github.com/pgomez-a/42_CPP_Piscine/blob/master/cpp02/ex01/Fixed.cpp
 */

std::ostream &	operator<<(std::ostream & o, Fixed const & rhs)
{
	o << rhs.toFloat();
	return (o);
}