1//===----------------------------------------------------------------------===// 2// 3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4// See https://llvm.org/LICENSE.txt for license information. 5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6// 7//===----------------------------------------------------------------------===// 8 9#ifndef _LIBCPP___MEMORY_TEMP_VALUE_H 10#define _LIBCPP___MEMORY_TEMP_VALUE_H 11 12#include <__config> 13#include <__memory/addressof.h> 14#include <__memory/allocator_traits.h> 15#include <__type_traits/aligned_storage.h> 16#include <__utility/forward.h> 17 18#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 19# pragma GCC system_header 20#endif 21 22_LIBCPP_BEGIN_NAMESPACE_STD 23 24template <class _Tp, class _Alloc> 25struct __temp_value { 26 typedef allocator_traits<_Alloc> _Traits; 27 28#ifdef _LIBCPP_CXX03_LANG 29 typename aligned_storage<sizeof(_Tp), _LIBCPP_ALIGNOF(_Tp)>::type __v; 30#else 31 union { _Tp __v; }; 32#endif 33 _Alloc &__a; 34 35 _LIBCPP_CONSTEXPR_SINCE_CXX20 _Tp *__addr() { 36#ifdef _LIBCPP_CXX03_LANG 37 return reinterpret_cast<_Tp*>(std::addressof(__v)); 38#else 39 return std::addressof(__v); 40#endif 41 } 42 43 _LIBCPP_CONSTEXPR_SINCE_CXX20 _Tp & get() { return *__addr(); } 44 45 template<class... _Args> 46 _LIBCPP_NO_CFI 47 _LIBCPP_CONSTEXPR_SINCE_CXX20 __temp_value(_Alloc &__alloc, _Args&& ... __args) : __a(__alloc) { 48 _Traits::construct(__a, __addr(), std::forward<_Args>(__args)...); 49 } 50 51 _LIBCPP_CONSTEXPR_SINCE_CXX20 ~__temp_value() { _Traits::destroy(__a, __addr()); } 52}; 53 54_LIBCPP_END_NAMESPACE_STD 55 56#endif // _LIBCPP___MEMORY_TEMP_VALUE_H 57