metaforce/Runtime/Flags.hpp

#pragma once

#include <type_traits>

namespace metaforce {
template <typename BitType>
class Flags {
public:
  using MaskType = std::underlying_type_t<BitType>;

  // constructors
  constexpr Flags() noexcept : m_mask(0) {}

  constexpr Flags(BitType bit) noexcept : m_mask(static_cast<MaskType>(bit)) {}

  constexpr Flags(Flags<BitType> const& rhs) noexcept : m_mask(rhs.m_mask) {}

  constexpr explicit Flags(MaskType flags) noexcept : m_mask(flags) {}

  [[nodiscard]] constexpr bool IsSet(Flags<BitType> const bit) const noexcept { return bool(*this & bit); }

  // relational operators
  bool operator==(Flags<BitType> const& rhs) const noexcept { return m_mask == rhs.m_mask; }

  // logical operator
  constexpr bool operator!() const noexcept { return !m_mask; }

  // bitwise operators
  constexpr Flags<BitType> operator&(Flags<BitType> const& rhs) const noexcept {
    return Flags<BitType>(m_mask & rhs.m_mask);
  }

  constexpr Flags<BitType> operator|(Flags<BitType> const& rhs) const noexcept {
    return Flags<BitType>(m_mask | rhs.m_mask);
  }

  constexpr Flags<BitType> operator^(Flags<BitType> const& rhs) const noexcept {
    return Flags<BitType>(m_mask ^ rhs.m_mask);
  }

  // assignment operators
  constexpr Flags<BitType>& operator=(Flags<BitType> const& rhs) noexcept {
    m_mask = rhs.m_mask;
    return *this;
  }

  constexpr Flags<BitType>& operator|=(Flags<BitType> const& rhs) noexcept {
    m_mask |= rhs.m_mask;
    return *this;
  }

  constexpr Flags<BitType>& operator&=(Flags<BitType> const& rhs) noexcept {
    m_mask &= rhs.m_mask;
    return *this;
  }

  constexpr Flags<BitType>& operator^=(Flags<BitType> const& rhs) noexcept {
    m_mask ^= rhs.m_mask;
    return *this;
  }

  // cast operators
  explicit constexpr operator bool() const noexcept { return m_mask != 0; }

  explicit constexpr operator MaskType() const noexcept { return m_mask; }

private:
  MaskType m_mask;
};
} // namespace metaforce