LiteLoaderBDS-1.16.40/LiteLoader/third-party/include/entt/entity/component.hpp
2023-03-01 23:21:09 -08:00

65 lines
1.8 KiB
C++

#ifndef ENTT_ENTITY_COMPONENT_HPP
#define ENTT_ENTITY_COMPONENT_HPP
#include <cstddef>
#include <type_traits>
#include "../config/config.h"
namespace entt {
/**
* @cond TURN_OFF_DOXYGEN
* Internal details not to be documented.
*/
namespace internal {
template<typename Type, typename = void>
struct in_place_delete: std::bool_constant<!(std::is_move_constructible_v<Type> && std::is_move_assignable_v<Type>)> {};
template<typename Type>
struct in_place_delete<Type, std::enable_if_t<Type::in_place_delete>>
: std::true_type {};
template<typename Type, typename = void>
struct page_size: std::integral_constant<std::size_t, !std::is_empty_v<ENTT_ETO_TYPE(Type)> * ENTT_PACKED_PAGE> {};
template<typename Type>
struct page_size<Type, std::enable_if_t<std::is_convertible_v<decltype(Type::page_size), std::size_t>>>
: std::integral_constant<std::size_t, Type::page_size> {};
} // namespace internal
/**
* Internal details not to be documented.
* @endcond
*/
/**
* @brief Common way to access various properties of components.
* @tparam Type Type of component.
*/
template<typename Type, typename = void>
struct component_traits {
static_assert(std::is_same_v<std::decay_t<Type>, Type>, "Unsupported type");
/*! @brief Component type. */
using type = Type;
/*! @brief Pointer stability, default is `false`. */
static constexpr bool in_place_delete = internal::in_place_delete<Type>::value;
/*! @brief Page size, default is `ENTT_PACKED_PAGE` for non-empty types. */
static constexpr std::size_t page_size = internal::page_size<Type>::value;
};
/**
* @brief Helper variable template.
* @tparam Type Type of component.
*/
template<class Type>
inline constexpr bool ignore_as_empty_v = (std::is_void_v<Type> || component_traits<Type>::page_size == 0u);
} // namespace entt
#endif