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-exception 7 // 8 //===----------------------------------------------------------------------===// 9 10 #ifndef _LIBCPP___MEMORY_CONSTRUCT_AT_H 11 #define _LIBCPP___MEMORY_CONSTRUCT_AT_H 12 13 #include <__assert> 14 #include <__config> 15 #include <__iterator/access.h> 16 #include <__memory/addressof.h> 17 #include <__memory/voidify.h> 18 #include <__type_traits/enable_if.h> 19 #include <__type_traits/is_array.h> 20 #include <__utility/declval.h> 21 #include <__utility/forward.h> 22 #include <__utility/move.h> 23 #include <new> 24 25 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 26 # pragma GCC system_header 27 #endif 28 29 _LIBCPP_BEGIN_NAMESPACE_STD 30 31 // construct_at 32 33 #if _LIBCPP_STD_VER > 17 34 35 template <class _Tp, class... _Args, class = decltype(::new(std::declval<void*>()) _Tp(std::declval<_Args>()...))> 36 _LIBCPP_HIDE_FROM_ABI constexpr _Tp* construct_at(_Tp* __location, _Args&&... __args) { 37 _LIBCPP_ASSERT(__location != nullptr, "null pointer given to construct_at"); 38 return ::new (_VSTD::__voidify(*__location)) _Tp(_VSTD::forward<_Args>(__args)...); 39 } 40 41 #endif 42 43 template <class _Tp, class... _Args, class = decltype(::new(std::declval<void*>()) _Tp(std::declval<_Args>()...))> 44 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR _Tp* __construct_at(_Tp* __location, _Args&&... __args) { 45 #if _LIBCPP_STD_VER > 17 46 return std::construct_at(__location, std::forward<_Args>(__args)...); 47 #else 48 return _LIBCPP_ASSERT(__location != nullptr, "null pointer given to construct_at"), 49 ::new (std::__voidify(*__location)) _Tp(std::forward<_Args>(__args)...); 50 #endif 51 } 52 53 // destroy_at 54 55 // The internal functions are available regardless of the language version (with the exception of the `__destroy_at` 56 // taking an array). 57 58 template <class _ForwardIterator> 59 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 60 _ForwardIterator __destroy(_ForwardIterator, _ForwardIterator); 61 62 template <class _Tp, typename enable_if<!is_array<_Tp>::value, int>::type = 0> 63 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 64 void __destroy_at(_Tp* __loc) { 65 _LIBCPP_ASSERT(__loc != nullptr, "null pointer given to destroy_at"); 66 __loc->~_Tp(); 67 } 68 69 #if _LIBCPP_STD_VER > 17 70 template <class _Tp, typename enable_if<is_array<_Tp>::value, int>::type = 0> 71 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 72 void __destroy_at(_Tp* __loc) { 73 _LIBCPP_ASSERT(__loc != nullptr, "null pointer given to destroy_at"); 74 _VSTD::__destroy(_VSTD::begin(*__loc), _VSTD::end(*__loc)); 75 } 76 #endif 77 78 template <class _ForwardIterator> 79 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 80 _ForwardIterator __destroy(_ForwardIterator __first, _ForwardIterator __last) { 81 for (; __first != __last; ++__first) 82 _VSTD::__destroy_at(_VSTD::addressof(*__first)); 83 return __first; 84 } 85 86 template <class _BidirectionalIterator> 87 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 88 _BidirectionalIterator __reverse_destroy(_BidirectionalIterator __first, _BidirectionalIterator __last) { 89 while (__last != __first) { 90 --__last; 91 std::__destroy_at(std::addressof(*__last)); 92 } 93 return __last; 94 } 95 96 #if _LIBCPP_STD_VER > 14 97 98 template <class _Tp, enable_if_t<!is_array_v<_Tp>, int> = 0> 99 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 100 void destroy_at(_Tp* __loc) { 101 _VSTD::__destroy_at(__loc); 102 } 103 104 #if _LIBCPP_STD_VER > 17 105 template <class _Tp, enable_if_t<is_array_v<_Tp>, int> = 0> 106 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 107 void destroy_at(_Tp* __loc) { 108 _VSTD::__destroy_at(__loc); 109 } 110 #endif 111 112 template <class _ForwardIterator> 113 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 114 void destroy(_ForwardIterator __first, _ForwardIterator __last) { 115 (void)_VSTD::__destroy(_VSTD::move(__first), _VSTD::move(__last)); 116 } 117 118 template <class _ForwardIterator, class _Size> 119 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 120 _ForwardIterator destroy_n(_ForwardIterator __first, _Size __n) { 121 for (; __n > 0; (void)++__first, --__n) 122 _VSTD::__destroy_at(_VSTD::addressof(*__first)); 123 return __first; 124 } 125 126 #endif // _LIBCPP_STD_VER > 14 127 128 _LIBCPP_END_NAMESPACE_STD 129 130 #endif // _LIBCPP___MEMORY_CONSTRUCT_AT_H 131