mathfuncs.h

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#pragma once

#include "mathematics.h"
#include <cmath>
#include <limits>
#include <numeric>
#include <cassert>

BEGIN_NAMESPACE_MATHEMATICS

class MathFuncs
{
public:
    template<typename T>
    static bool inRange(T input, T minimum, T maximum);

    template<typename T>
    static T ensureRange(T input, T minimum, T maximum);

    template<typename T>
    static bool areSame(T first, T second, T epsilon = (T) std::numeric_limits<T>::epsilon());

    template<typename T>
    static bool isZero(T input, T epsilon = (T) std::numeric_limits<T>::epsilon());

    template<typename T>
    static T gcd(T first, T second);

    template<typename T>
    static T lcm(T first, T second);
};

template<typename T>
bool MathFuncs::inRange(T input, T minimum, T maximum)
{
    return (minimum <= input) && (input <= maximum);
}

template<typename T>
T MathFuncs::ensureRange(T input, T minimum, T maximum)
{
    assert(minimum <= maximum);
    if (input < minimum)
        return minimum;
    if (input > maximum)
        return maximum;
    return input;
}

template <typename T>
bool MathFuncs::areSame(T first, T second, T epsilon)
{
    static_assert(std::is_arithmetic_v<T>, "areSame type not supported.");

    if constexpr (std::is_integral<T>::value)
    {
        if constexpr (!std::is_unsigned<T>::value)
        {
            if (epsilon < 0)
                epsilon = -epsilon; // compiler doesn't allow this for unsigned types
        }

        T max = first;
        T min = second;
        if (first < second)
        {
            max = second;
            min = first;
        }
        return max - min <= epsilon;
    }
    return std::fabs(first - second) <= std::fabs(epsilon);
}

template<typename T>
bool MathFuncs::isZero(T input, T epsilon)
{
    return areSame(input, T(0), epsilon);
}

template<typename T>
T MathFuncs::gcd(T first, T second)
{
    return std::gcd(first, second);
}

template<typename T>
T MathFuncs::lcm(T first, T second)
{
    return std::lcm(first, second);
}

END_NAMESPACE_MATHEMATICS