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1// -*- C++ -*-2//===----------------------------------------------------------------------===//3//4// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.5// See https://llvm.org/LICENSE.txt for license information.6// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception7//8//===----------------------------------------------------------------------===//9 10#ifndef _LIBCPP___MEMORY_CONSTRUCT_AT_H11#define _LIBCPP___MEMORY_CONSTRUCT_AT_H12 13#include <__assert>14#include <__config>15#include <__memory/addressof.h>16#include <__new/placement_new_delete.h>17#include <__type_traits/is_array.h>18#include <__utility/declval.h>19#include <__utility/forward.h>20 21#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)22# pragma GCC system_header23#endif24 25_LIBCPP_PUSH_MACROS26#include <__undef_macros>27 28_LIBCPP_BEGIN_NAMESPACE_STD29 30// construct_at31 32#if _LIBCPP_STD_VER >= 2033 34template <class _Tp, class... _Args, class = decltype(::new(std::declval<void*>()) _Tp(std::declval<_Args>()...))>35_LIBCPP_HIDE_FROM_ABI constexpr _Tp* construct_at(_Tp* _LIBCPP_DIAGNOSE_NULLPTR __location, _Args&&... __args) {36 _LIBCPP_ASSERT_NON_NULL(__location != nullptr, "null pointer given to construct_at");37 return ::new (static_cast<void*>(__location)) _Tp(std::forward<_Args>(__args)...);38}39 40#endif41 42template <class _Tp, class... _Args, class = decltype(::new(std::declval<void*>()) _Tp(std::declval<_Args>()...))>43_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Tp* __construct_at(_Tp* __location, _Args&&... __args) {44#if _LIBCPP_STD_VER >= 2045 return std::construct_at(__location, std::forward<_Args>(__args)...);46#else47 return _LIBCPP_ASSERT_NON_NULL(__location != nullptr, "null pointer given to construct_at"),48 ::new (static_cast<void*>(__location)) _Tp(std::forward<_Args>(__args)...);49#endif50}51 52// destroy_at53 54// The internal functions are available regardless of the language version (with the exception of the `__destroy_at`55// taking an array).56 57template <class _Tp>58_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __destroy_at(_Tp* __loc) {59 _LIBCPP_ASSERT_NON_NULL(__loc != nullptr, "null pointer given to destroy_at");60#if _LIBCPP_STD_VER >= 2061 if constexpr (is_array_v<_Tp>) {62 for (auto&& __val : *__loc)63 std::__destroy_at(std::addressof(__val));64 } else65#endif66 {67 __loc->~_Tp();68 }69}70 71#if _LIBCPP_STD_VER >= 1772template <class _Tp>73_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void destroy_at(_Tp* _LIBCPP_DIAGNOSE_NULLPTR __loc) {74 std::__destroy_at(__loc);75}76#endif // _LIBCPP_STD_VER >= 1777 78_LIBCPP_END_NAMESPACE_STD79 80_LIBCPP_POP_MACROS81 82#endif // _LIBCPP___MEMORY_CONSTRUCT_AT_H83