Tuning.h

#ifndef MCC_TUNING_TUNING_H
#define MCC_TUNING_TUNING_H
 
#include <float.h>
 
#include <MCC/Pitch/Pitch.h>
 
namespace MCC {

class Tuning {
    MCC::Pitch _reference;
    float _frequency;
 
public:
    constexpr Tuning() noexcept : _reference(), _frequency(0.0f) {}

    constexpr Tuning(MCC::Pitch reference, float frequency) noexcept
        : _reference(IsUsable(reference, frequency)
              ? reference
              : MCC::Pitch::Invalid()),
          _frequency(IsUsable(reference, frequency) ? frequency : 0.0f) {}

    static constexpr Tuning Standard() noexcept {
        return Tuning(MCC::Pitch(MCC::Letter::A, 4), 440.0f);
    }

    static constexpr Tuning Invalid() noexcept { return Tuning(); }

    constexpr bool IsValid() const noexcept { return _reference.IsValid(); }

    constexpr MCC::Pitch Reference() const noexcept { return _reference; }

    constexpr float ReferenceFrequency() const noexcept { return _frequency; }

    friend constexpr bool operator==(Tuning a, Tuning b) noexcept {
        return a._reference == b._reference && a._frequency == b._frequency;
    }
 
    friend constexpr bool operator!=(Tuning a, Tuning b) noexcept {
        return !(a == b);
    }
 
private:
    static constexpr bool IsUsable(MCC::Pitch reference, float frequency) noexcept {
        // NaN fails both comparisons; infinity fails the upper bound.
        return reference.IsValid() && frequency > 0.0f && frequency <= FLT_MAX;
    }
};
 
} // namespace MCC
 
#endif // MCC_TUNING_TUNING_H