forked from Green-Sky/tomato
Green Sky
5c7231b7a3
git-subtree-dir: external/entt/entt git-subtree-split: fef921132cae7588213d0f9bcd2fb9c8ffd8b7fc
57 lines
1.5 KiB
C++
57 lines
1.5 KiB
C++
#ifndef ENTT_CORE_MONOSTATE_HPP
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#define ENTT_CORE_MONOSTATE_HPP
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#include "../config/config.h"
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#include "fwd.hpp"
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namespace entt {
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/**
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* @brief Minimal implementation of the monostate pattern.
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*
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* A minimal, yet complete configuration system built on top of the monostate
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* pattern. Thread safe by design, it works only with basic types like `int`s or
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* `bool`s.<br/>
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* Multiple types and therefore more than one value can be associated with a
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* single key. Because of this, users must pay attention to use the same type
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* both during an assignment and when they try to read back their data.
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* Otherwise, they can incur in unexpected results.
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*/
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template<id_type>
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struct monostate {
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/**
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* @brief Assigns a value of a specific type to a given key.
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* @tparam Type Type of the value to assign.
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* @param val User data to assign to the given key.
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*/
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template<typename Type>
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void operator=(Type val) const noexcept {
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value<Type> = val;
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}
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/**
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* @brief Gets a value of a specific type for a given key.
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* @tparam Type Type of the value to get.
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* @return Stored value, if any.
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*/
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template<typename Type>
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operator Type() const noexcept {
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return value<Type>;
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}
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private:
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template<typename Type>
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inline static ENTT_MAYBE_ATOMIC(Type) value{};
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};
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/**
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* @brief Helper variable template.
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* @tparam Value Value used to differentiate between different variables.
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*/
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template<id_type Value>
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inline monostate<Value> monostate_v = {};
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} // namespace entt
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#endif
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