LiteLoaderBDS-1.16.40/LiteLoader/Header/third-party/entt/entity/entity.hpp
2022-09-21 19:47:03 +08:00

352 lines
11 KiB
C++

#ifndef ENTT_ENTITY_ENTITY_HPP
#define ENTT_ENTITY_ENTITY_HPP
#include <cstddef>
#include <cstdint>
#include <type_traits>
#include "../config/config.h"
namespace entt {
/**
* @cond TURN_OFF_DOXYGEN
* Internal details not to be documented.
*/
namespace internal {
template<typename, typename = void>
struct entt_traits;
template<typename Type>
struct entt_traits<Type, std::enable_if_t<std::is_enum_v<Type>>>
: entt_traits<std::underlying_type_t<Type>>
{};
template<typename Type>
struct entt_traits<Type, std::enable_if_t<std::is_class_v<Type>>>
: entt_traits<typename Type::entity_type>
{};
template<>
struct entt_traits<std::uint32_t> {
using entity_type = std::uint32_t;
using version_type = std::uint16_t;
using difference_type = std::int64_t;
static constexpr entity_type entity_mask = 0xFFFFF;
static constexpr entity_type version_mask = 0xFFF;
static constexpr std::size_t entity_shift = 20u;
};
template<>
struct entt_traits<std::uint64_t> {
using entity_type = std::uint64_t;
using version_type = std::uint32_t;
using difference_type = std::int64_t;
static constexpr entity_type entity_mask = 0xFFFFFFFF;
static constexpr entity_type version_mask = 0xFFFFFFFF;
static constexpr std::size_t entity_shift = 32u;
};
}
/**
* Internal details not to be documented.
* @endcond
*/
/**
* @brief Entity traits.
* @tparam Type Type of identifier.
*/
template<typename Type>
class entt_traits: private internal::entt_traits<Type> {
using traits_type = internal::entt_traits<Type>;
public:
/*! @brief Value type. */
using value_type = Type;
/*! @brief Underlying entity type. */
using entity_type = typename traits_type::entity_type;
/*! @brief Underlying version type. */
using version_type = typename traits_type::version_type;
/*! @brief Difference type. */
using difference_type = typename traits_type::difference_type;
/**
* @brief Converts an entity to its underlying type.
* @param value The value to convert.
* @return The integral representation of the given value.
*/
[[nodiscard]] static constexpr entity_type to_integral(const value_type value) ENTT_NOEXCEPT {
return static_cast<entity_type>(value);
}
/**
* @brief Returns the entity part once converted to the underlying type.
* @param value The value to convert.
* @return The integral representation of the entity part.
*/
[[nodiscard]] static constexpr entity_type to_entity(const value_type value) ENTT_NOEXCEPT {
return (to_integral(value) & traits_type::entity_mask);
}
/**
* @brief Returns the version part once converted to the underlying type.
* @param value The value to convert.
* @return The integral representation of the version part.
*/
[[nodiscard]] static constexpr version_type to_version(const value_type value) ENTT_NOEXCEPT {
constexpr auto mask = (traits_type::version_mask << traits_type::entity_shift);
return ((to_integral(value) & mask) >> traits_type::entity_shift);
}
/**
* @brief Constructs an identifier from its parts.
*
* If the version part is not provided, a tombstone is returned.<br/>
* If the entity part is not provided, a null identifier is returned.
*
* @param entity The entity part of the identifier.
* @param version The version part of the identifier.
* @return A properly constructed identifier.
*/
[[nodiscard]] static constexpr value_type construct(const entity_type entity = traits_type::entity_mask, const version_type version = traits_type::version_mask) ENTT_NOEXCEPT {
return value_type{(entity & traits_type::entity_mask) | (static_cast<entity_type>(version) << traits_type::entity_shift)};
}
};
/**
* @brief Converts an entity to its underlying type.
* @tparam Entity The value type.
* @param entity The value to convert.
* @return The integral representation of the given value.
*/
template<typename Entity>
[[nodiscard]] constexpr auto to_integral(const Entity entity) ENTT_NOEXCEPT {
return entt_traits<Entity>::to_integral(entity);
}
/*! @brief Null object for all entity identifiers. */
struct null_t {
/**
* @brief Converts the null object to identifiers of any type.
* @tparam Entity Type of entity identifier.
* @return The null representation for the given type.
*/
template<typename Entity>
[[nodiscard]] constexpr operator Entity() const ENTT_NOEXCEPT {
return entt_traits<Entity>::construct();
}
/**
* @brief Compares two null objects.
* @param other A null object.
* @return True in all cases.
*/
[[nodiscard]] constexpr bool operator==([[maybe_unused]] const null_t other) const ENTT_NOEXCEPT {
return true;
}
/**
* @brief Compares two null objects.
* @param other A null object.
* @return False in all cases.
*/
[[nodiscard]] constexpr bool operator!=([[maybe_unused]] const null_t other) const ENTT_NOEXCEPT {
return false;
}
/**
* @brief Compares a null object and an entity identifier of any type.
* @tparam Entity Type of entity identifier.
* @param entity Entity identifier with which to compare.
* @return False if the two elements differ, true otherwise.
*/
template<typename Entity>
[[nodiscard]] constexpr bool operator==(const Entity entity) const ENTT_NOEXCEPT {
return entt_traits<Entity>::to_entity(entity) == entt_traits<Entity>::to_entity(*this);
}
/**
* @brief Compares a null object and an entity identifier of any type.
* @tparam Entity Type of entity identifier.
* @param entity Entity identifier with which to compare.
* @return True if the two elements differ, false otherwise.
*/
template<typename Entity>
[[nodiscard]] constexpr bool operator!=(const Entity entity) const ENTT_NOEXCEPT {
return !(entity == *this);
}
/**
* @brief Creates a null object from an entity identifier of any type.
* @tparam Entity Type of entity identifier.
* @param entity Entity identifier to turn into a null object.
* @return The null representation for the given identifier.
*/
template<typename Entity>
[[nodiscard]] constexpr Entity operator|(const Entity entity) const ENTT_NOEXCEPT {
return entt_traits<Entity>::construct(entt_traits<Entity>::to_entity(*this), entt_traits<Entity>::to_version(entity));
}
};
/**
* @brief Compares a null object and an entity identifier of any type.
* @tparam Entity Type of entity identifier.
* @param entity Entity identifier with which to compare.
* @param other A null object yet to be converted.
* @return False if the two elements differ, true otherwise.
*/
template<typename Entity>
[[nodiscard]] constexpr bool operator==(const Entity entity, const null_t other) ENTT_NOEXCEPT {
return other.operator==(entity);
}
/**
* @brief Compares a null object and an entity identifier of any type.
* @tparam Entity Type of entity identifier.
* @param entity Entity identifier with which to compare.
* @param other A null object yet to be converted.
* @return True if the two elements differ, false otherwise.
*/
template<typename Entity>
[[nodiscard]] constexpr bool operator!=(const Entity entity, const null_t other) ENTT_NOEXCEPT {
return !(other == entity);
}
/*! @brief Tombstone object for all entity identifiers. */
struct tombstone_t {
/**
* @brief Converts the tombstone object to identifiers of any type.
* @tparam Entity Type of entity identifier.
* @return The tombstone representation for the given type.
*/
template<typename Entity>
[[nodiscard]] constexpr operator Entity() const ENTT_NOEXCEPT {
return entt_traits<Entity>::construct();
}
/**
* @brief Compares two tombstone objects.
* @param other A tombstone object.
* @return True in all cases.
*/
[[nodiscard]] constexpr bool operator==([[maybe_unused]] const tombstone_t other) const ENTT_NOEXCEPT {
return true;
}
/**
* @brief Compares two tombstone objects.
* @param other A tombstone object.
* @return False in all cases.
*/
[[nodiscard]] constexpr bool operator!=([[maybe_unused]] const tombstone_t other) const ENTT_NOEXCEPT {
return false;
}
/**
* @brief Compares a tombstone object and an entity identifier of any type.
* @tparam Entity Type of entity identifier.
* @param entity Entity identifier with which to compare.
* @return False if the two elements differ, true otherwise.
*/
template<typename Entity>
[[nodiscard]] constexpr bool operator==(const Entity entity) const ENTT_NOEXCEPT {
return entt_traits<Entity>::to_version(entity) == entt_traits<Entity>::to_version(*this);
}
/**
* @brief Compares a tombstone object and an entity identifier of any type.
* @tparam Entity Type of entity identifier.
* @param entity Entity identifier with which to compare.
* @return True if the two elements differ, false otherwise.
*/
template<typename Entity>
[[nodiscard]] constexpr bool operator!=(const Entity entity) const ENTT_NOEXCEPT {
return !(entity == *this);
}
/**
* @brief Creates a tombstone object from an entity identifier of any type.
* @tparam Entity Type of entity identifier.
* @param entity Entity identifier to turn into a tombstone object.
* @return The tombstone representation for the given identifier.
*/
template<typename Entity>
[[nodiscard]] constexpr Entity operator|(const Entity entity) const ENTT_NOEXCEPT {
return entt_traits<Entity>::construct(entt_traits<Entity>::to_entity(entity));
}
};
/**
* @brief Compares a tombstone object and an entity identifier of any type.
* @tparam Entity Type of entity identifier.
* @param entity Entity identifier with which to compare.
* @param other A tombstone object yet to be converted.
* @return False if the two elements differ, true otherwise.
*/
template<typename Entity>
[[nodiscard]] constexpr bool operator==(const Entity entity, const tombstone_t other) ENTT_NOEXCEPT {
return other.operator==(entity);
}
/**
* @brief Compares a tombstone object and an entity identifier of any type.
* @tparam Entity Type of entity identifier.
* @param entity Entity identifier with which to compare.
* @param other A tombstone object yet to be converted.
* @return True if the two elements differ, false otherwise.
*/
template<typename Entity>
[[nodiscard]] constexpr bool operator!=(const Entity entity, const tombstone_t other) ENTT_NOEXCEPT {
return !(other == entity);
}
/**
* @brief Compile-time constant for null entities.
*
* There exist implicit conversions from this variable to entity identifiers of
* any allowed type. Similarly, there exist comparision operators between the
* null entity and any other entity identifier.
*/
inline constexpr null_t null{};
/**
* @brief Compile-time constant for tombstone entities.
*
* There exist implicit conversions from this variable to entity identifiers of
* any allowed type. Similarly, there exist comparision operators between the
* tombstone entity and any other entity identifier.
*/
inline constexpr tombstone_t tombstone{};
}
#endif