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>()...))>
construct_at(_Tp * __location,_Args &&...__args)39 _LIBCPP_HIDE_FROM_ABI constexpr _Tp* construct_at(_Tp* __location, _Args&&... __args) {
40 _LIBCPP_ASSERT_NON_NULL(__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>()...))>
__construct_at(_Tp * __location,_Args &&...__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_NON_NULL(__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 _ForwardIterator __destroy(_ForwardIterator, _ForwardIterator);
63
64 template <class _Tp, __enable_if_t<!is_array<_Tp>::value, int> = 0>
__destroy_at(_Tp * __loc)65 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __destroy_at(_Tp* __loc) {
66 _LIBCPP_ASSERT_NON_NULL(__loc != nullptr, "null pointer given to destroy_at");
67 __loc->~_Tp();
68 }
69
70 #if _LIBCPP_STD_VER >= 20
71 template <class _Tp, __enable_if_t<is_array<_Tp>::value, int> = 0>
__destroy_at(_Tp * __loc)72 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __destroy_at(_Tp* __loc) {
73 _LIBCPP_ASSERT_NON_NULL(__loc != nullptr, "null pointer given to destroy_at");
74 std::__destroy(std::begin(*__loc), std::end(*__loc));
75 }
76 #endif
77
78 template <class _ForwardIterator>
79 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator
__destroy(_ForwardIterator __first,_ForwardIterator __last)80 __destroy(_ForwardIterator __first, _ForwardIterator __last) {
81 for (; __first != __last; ++__first)
82 std::__destroy_at(std::addressof(*__first));
83 return __first;
84 }
85
86 template <class _BidirectionalIterator>
87 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _BidirectionalIterator
__reverse_destroy(_BidirectionalIterator __first,_BidirectionalIterator __last)88 __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 >= 17
97
98 template <class _Tp, enable_if_t<!is_array_v<_Tp>, int> = 0>
destroy_at(_Tp * __loc)99 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void destroy_at(_Tp* __loc) {
100 std::__destroy_at(__loc);
101 }
102
103 # if _LIBCPP_STD_VER >= 20
104 template <class _Tp, enable_if_t<is_array_v<_Tp>, int> = 0>
destroy_at(_Tp * __loc)105 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void destroy_at(_Tp* __loc) {
106 std::__destroy_at(__loc);
107 }
108 # endif
109
110 template <class _ForwardIterator>
destroy(_ForwardIterator __first,_ForwardIterator __last)111 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void destroy(_ForwardIterator __first, _ForwardIterator __last) {
112 (void)std::__destroy(std::move(__first), std::move(__last));
113 }
114
115 template <class _ForwardIterator, class _Size>
destroy_n(_ForwardIterator __first,_Size __n)116 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _ForwardIterator destroy_n(_ForwardIterator __first, _Size __n) {
117 for (; __n > 0; (void)++__first, --__n)
118 std::__destroy_at(std::addressof(*__first));
119 return __first;
120 }
121
122 #endif // _LIBCPP_STD_VER >= 17
123
124 _LIBCPP_END_NAMESPACE_STD
125
126 _LIBCPP_POP_MACROS
127
128 #endif // _LIBCPP___MEMORY_CONSTRUCT_AT_H
129