#ifndef POWER_OF_TWO_HH

#define POWER_OF_TWO_HH

#include "narrow.hh"

#include <bit>

#include <cassert>

#include <concepts>

#include <cstdint>

namespace openmsx {

/**

 * A constexpr power_of_two struct for power of two numbers, with compact

 * storage and built-in value correctness assertion. Additionally, the compiler

 * optimises multiplication / division / modulo operations to bit shifts.

 */

template<std::unsigned_integral T>

struct power_of_two {

	constexpr power_of_two(T size)

		: exponent(narrow_cast<uint8_t>(std::bit_width(size - 1)))

	{

		assert(std::has_single_bit(size));

	};

	[[nodiscard]] constexpr operator T() const

	{

		return T{1} << exponent;

	}

	uint8_t exponent = 0;

};

} // namespace openmsx

#endif