#pragma once

#include <stddef.h> // size_t

namespace partial19 {

/// Minimal constexpr enabled implemenation of std::bitset

/// Only the mandatory methods are implemented

template<size_t Count> struct Bitset {

private:

using T = unsigned;

constexpr static auto BitsPerT = 8 * sizeof(T);

constexpr static auto Len = (Count + BitsPerT - 1) / BitsPerT;

T m[Len] = {};

public:

constexpr static auto count = Count;

constexpr bool operator==(const Bitset& o) const = default;

[[nodiscard]] constexpr bool operator[](size_t index) const noexcept {

return 0 != (m[index / BitsPerT] & (1u << (index % BitsPerT)));

}

constexpr void reset() noexcept {

for (auto& v : m) v = {};

}

constexpr void setAt(size_t index) noexcept { m[index / BitsPerT] |= (1u << (index % BitsPerT)); }

constexpr void resetAt(size_t index) noexcept { m[index / BitsPerT] &= ~static_cast<T>(1u << (index % BitsPerT)); }

};

} // namespace partial19