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_PUSH_MACROS 30 #include <__undef_macros> 31 32 _LIBCPP_BEGIN_NAMESPACE_STD 33 34 // construct_at 35 36 #if _LIBCPP_STD_VER >= 20 37 38 template <class _Tp, class... _Args, class = decltype(::new(std::declval<void*>()) _Tp(std::declval<_Args>()...))> 39 _LIBCPP_HIDE_FROM_ABI constexpr _Tp* construct_at(_Tp* __location, _Args&&... __args) { 40 _LIBCPP_ASSERT_UNCATEGORIZED(__location != nullptr, "null pointer given to construct_at"); 41 return ::new (std::__voidify(*__location)) _Tp(std::forward<_Args>(__args)...); 42 } 43 44 #endif 45 46 template <class _Tp, class... _Args, class = decltype(::new(std::declval<void*>()) _Tp(std::declval<_Args>()...))> 47 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR _Tp* __construct_at(_Tp* __location, _Args&&... __args) { 48 #if _LIBCPP_STD_VER >= 20 49 return std::construct_at(__location, std::forward<_Args>(__args)...); 50 #else 51 return _LIBCPP_ASSERT_UNCATEGORIZED(__location != nullptr, "null pointer given to construct_at"), 52 ::new (std::__voidify(*__location)) _Tp(std::forward<_Args>(__args)...); 53 #endif 54 } 55 56 // destroy_at 57 58 // The internal functions are available regardless of the language version (with the exception of the `__destroy_at` 59 // taking an array). 60 61 template <class _ForwardIterator> 62 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 63 _ForwardIterator __destroy(_ForwardIterator, _ForwardIterator); 64 65 template <class _Tp, typename enable_if<!is_array<_Tp>::value, int>::type = 0> 66 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 67 void __destroy_at(_Tp* __loc) { 68 _LIBCPP_ASSERT_UNCATEGORIZED(__loc != nullptr, "null pointer given to destroy_at"); 69 __loc->~_Tp(); 70 } 71 72 #if _LIBCPP_STD_VER >= 20 73 template <class _Tp, typename enable_if<is_array<_Tp>::value, int>::type = 0> 74 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 75 void __destroy_at(_Tp* __loc) { 76 _LIBCPP_ASSERT_UNCATEGORIZED(__loc != nullptr, "null pointer given to destroy_at"); 77 std::__destroy(std::begin(*__loc), std::end(*__loc)); 78 } 79 #endif 80 81 template <class _ForwardIterator> 82 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 83 _ForwardIterator __destroy(_ForwardIterator __first, _ForwardIterator __last) { 84 for (; __first != __last; ++__first) 85 std::__destroy_at(std::addressof(*__first)); 86 return __first; 87 } 88 89 template <class _BidirectionalIterator> 90 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 91 _BidirectionalIterator __reverse_destroy(_BidirectionalIterator __first, _BidirectionalIterator __last) { 92 while (__last != __first) { 93 --__last; 94 std::__destroy_at(std::addressof(*__last)); 95 } 96 return __last; 97 } 98 99 #if _LIBCPP_STD_VER >= 17 100 101 template <class _Tp, enable_if_t<!is_array_v<_Tp>, int> = 0> 102 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 103 void destroy_at(_Tp* __loc) { 104 std::__destroy_at(__loc); 105 } 106 107 #if _LIBCPP_STD_VER >= 20 108 template <class _Tp, enable_if_t<is_array_v<_Tp>, int> = 0> 109 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 110 void destroy_at(_Tp* __loc) { 111 std::__destroy_at(__loc); 112 } 113 #endif 114 115 template <class _ForwardIterator> 116 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 117 void destroy(_ForwardIterator __first, _ForwardIterator __last) { 118 (void)std::__destroy(std::move(__first), std::move(__last)); 119 } 120 121 template <class _ForwardIterator, class _Size> 122 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 123 _ForwardIterator destroy_n(_ForwardIterator __first, _Size __n) { 124 for (; __n > 0; (void)++__first, --__n) 125 std::__destroy_at(std::addressof(*__first)); 126 return __first; 127 } 128 129 #endif // _LIBCPP_STD_VER >= 17 130 131 _LIBCPP_END_NAMESPACE_STD 132 133 _LIBCPP_POP_MACROS 134 135 #endif // _LIBCPP___MEMORY_CONSTRUCT_AT_H 136