Fraction.cpp

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// Copyright (c) 2008-2019 OpenShot Studios, LLC
//
// SPDX-License-Identifier: LGPL-3.0-or-later
 
#include "Fraction.h"
#include <cmath>
 
using namespace openshot;
 
// Delegating constructors
Fraction::Fraction() : Fraction::Fraction(1, 1) {}
 
Fraction::Fraction(std::pair<int, int> pair)
    : Fraction::Fraction(pair.first, pair.second) {}
 
Fraction::Fraction(std::map<std::string, int> mapping)
    : Fraction::Fraction(mapping["num"], mapping["den"]) {}
 
Fraction::Fraction(std::vector<int> vector)
    : Fraction::Fraction(vector[0], vector[1]) {}
 
// Full constructor
Fraction::Fraction(int num, int den) :
    num(num), den(den) {}
 
// Return this fraction as a float (i.e. 1/2 = 0.5)
float Fraction::ToFloat() {
    return float(num) / float(den);
}
 
// Return this fraction as a double (i.e. 1/2 = 0.5)
double Fraction::ToDouble() const {
    return double(num) / double(den);
}
 
// Return a rounded integer of the frame rate (for example 30000/1001 returns 30 fps)
int Fraction::ToInt() {
    return round((double) num / den);
}
 
// Calculate the greatest common denominator
int Fraction::GreatestCommonDenominator() {
    int first = num;
    int second = den;
 
    // Find the biggest whole number that will divide into both the numerator
    // and denominator
    int t;
    while (second != 0) {
        t = second;
        second = first % second;
        first = t;
    }
    return first;
}
 
void Fraction::Reduce() {
    // Get the greatest common denominator
    int GCD = GreatestCommonDenominator();
    if (GCD == 0) {
        return;
    }
 
    // Reduce this fraction to the smallest possible whole numbers
    num = num / GCD;
    den = den / GCD;
}
 
// Return the reciprocal as a new Fraction
Fraction Fraction::Reciprocal() const
{
    // flip the fraction
    return Fraction(den, num);
}