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