57 lines
998 B
C++
57 lines
998 B
C++
#pragma once
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#include <ext/aligned_buffer.h>
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#include <utility>
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template <class T>
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class Placeholder
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{
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public:
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Placeholder() = default;
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Placeholder(Placeholder &) = delete;
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Placeholder(Placeholder &&) = delete;
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~Placeholder()
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{
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if (initialized) get().~T();
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};
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bool is_initialized() { return initialized; }
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T &get() noexcept
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{
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assert(initialized);
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return *data._M_ptr();
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}
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const T &get() const noexcept
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{
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assert(initialized);
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return *data._M_ptr();
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}
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void set(const T &item)
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{
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new (data._M_addr()) T(item);
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initialized = true;
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}
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void set(T &&item)
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{
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new (data._M_addr()) T(std::move(item));
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initialized = true;
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}
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template <class... Args>
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void emplace(Args &&... args)
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{
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new (data._M_addr()) T(args...);
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initialized = true;
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}
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private:
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__gnu_cxx::__aligned_buffer<T> data;
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bool initialized = false;
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};
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