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entity: make null_t public

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This commit is contained in:
Michele Caini
2020-07-06 09:24:56 +02:00
parent 7889ca1ca7
commit 75b19230eb
1 changed files with 46 additions and 18 deletions
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64
src/entt/entity/entity.hpp
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@@ -121,34 +121,51 @@ template<typename Entity>
}
/**
* @cond TURN_OFF_DOXYGEN
* Internal details not to be documented.
*/
namespace internal {
struct null {
/*! @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 identifier.
*/
template<typename Entity>
[[nodiscard]] constexpr operator Entity() const ENTT_NOEXCEPT {
return Entity{entt_traits<Entity>::entity_mask};
}
[[nodiscard]] constexpr bool operator==(null) const ENTT_NOEXCEPT {
/**
* @brief Compares two null objects.
* @return True in all cases.
*/
[[nodiscard]] constexpr bool operator==(null_t) const ENTT_NOEXCEPT {
return true;
}
[[nodiscard]] constexpr bool operator!=(null) const ENTT_NOEXCEPT {
/**
* @brief Compares two null objects.
* @return False in all cases.
*/
[[nodiscard]] constexpr bool operator!=(null_t) 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 (to_integral(entity) & entt_traits<Entity>::entity_mask) == to_integral(static_cast<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);
@@ -156,21 +173,32 @@ struct null {
};
/**
* @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, null other) ENTT_NOEXCEPT {
[[nodiscard]] constexpr bool operator==(const Entity entity, 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, null other) ENTT_NOEXCEPT {
[[nodiscard]] constexpr bool operator!=(const Entity entity, null_t other) ENTT_NOEXCEPT {
return !(other == entity);
}
}
/**
* Internal details not to be documented.
* @endcond
@@ -184,7 +212,7 @@ template<typename Entity>
* any allowed type. Similarly, there exist comparision operators between the
* null entity and any other entity identifier.
*/
inline constexpr auto null = internal::null{};
inline constexpr null_t null{};
}