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42526146 PE |
1 | // nonstandard construct and destroy functions -*- C++ -*- |
2 | ||
6441eb6d | 3 | // Copyright (C) 2001-2025 Free Software Foundation, Inc. |
42526146 PE |
4 | // |
5 | // This file is part of the GNU ISO C++ Library. This library is free | |
6 | // software; you can redistribute it and/or modify it under the | |
7 | // terms of the GNU General Public License as published by the | |
748086b7 | 8 | // Free Software Foundation; either version 3, or (at your option) |
42526146 PE |
9 | // any later version. |
10 | ||
11 | // This library is distributed in the hope that it will be useful, | |
12 | // but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | // GNU General Public License for more details. | |
15 | ||
748086b7 JJ |
16 | // Under Section 7 of GPL version 3, you are granted additional |
17 | // permissions described in the GCC Runtime Library Exception, version | |
18 | // 3.1, as published by the Free Software Foundation. | |
42526146 | 19 | |
748086b7 JJ |
20 | // You should have received a copy of the GNU General Public License and |
21 | // a copy of the GCC Runtime Library Exception along with this program; | |
22 | // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see | |
23 | // <http://www.gnu.org/licenses/>. | |
42526146 | 24 | |
725dc051 BK |
25 | /* |
26 | * | |
27 | * Copyright (c) 1994 | |
28 | * Hewlett-Packard Company | |
29 | * | |
30 | * Permission to use, copy, modify, distribute and sell this software | |
31 | * and its documentation for any purpose is hereby granted without fee, | |
32 | * provided that the above copyright notice appear in all copies and | |
33 | * that both that copyright notice and this permission notice appear | |
34 | * in supporting documentation. Hewlett-Packard Company makes no | |
35 | * representations about the suitability of this software for any | |
36 | * purpose. It is provided "as is" without express or implied warranty. | |
37 | * | |
38 | * | |
39 | * Copyright (c) 1996,1997 | |
40 | * Silicon Graphics Computer Systems, Inc. | |
41 | * | |
42 | * Permission to use, copy, modify, distribute and sell this software | |
43 | * and its documentation for any purpose is hereby granted without fee, | |
44 | * provided that the above copyright notice appear in all copies and | |
45 | * that both that copyright notice and this permission notice appear | |
46 | * in supporting documentation. Silicon Graphics makes no | |
47 | * representations about the suitability of this software for any | |
48 | * purpose. It is provided "as is" without express or implied warranty. | |
49 | */ | |
50 | ||
f910786b | 51 | /** @file bits/stl_construct.h |
729e3d3f | 52 | * This is an internal header file, included by other library headers. |
f910786b | 53 | * Do not attempt to use it directly. @headername{memory} |
725dc051 BK |
54 | */ |
55 | ||
3d7c150e BK |
56 | #ifndef _STL_CONSTRUCT_H |
57 | #define _STL_CONSTRUCT_H 1 | |
725dc051 | 58 | |
a6863e25 | 59 | #include <new> |
6401164d | 60 | #include <bits/move.h> |
85f24114 JW |
61 | #include <bits/stl_iterator_base_types.h> // for iterator_traits |
62 | #include <bits/stl_iterator_base_funcs.h> // for advance | |
63 | ||
64 | /* This file provides the C++17 functions std::destroy_at, std::destroy, and | |
65 | * std::destroy_n, and the C++20 function std::construct_at. | |
66 | * It also provides std::_Construct, std::_Destroy,and std::_Destroy_n functions | |
67 | * which are defined in all standard modes and so can be used in C++98-14 code. | |
162c40a4 JW |
68 | * The _Destroy functions will dispatch to destroy_at during constant |
69 | * evaluation, because calls to that function are intercepted by the compiler | |
70 | * to allow use in constant expressions. | |
85f24114 | 71 | */ |
725dc051 | 72 | |
12ffa228 BK |
73 | namespace std _GLIBCXX_VISIBILITY(default) |
74 | { | |
75 | _GLIBCXX_BEGIN_NAMESPACE_VERSION | |
3cbc7af0 | 76 | |
8539c561 | 77 | #if __glibcxx_raw_memory_algorithms // >= C++17 |
85f24114 JW |
78 | template <typename _Tp> |
79 | _GLIBCXX20_CONSTEXPR inline void | |
80 | destroy_at(_Tp* __location) | |
81 | { | |
82 | if constexpr (__cplusplus > 201703L && is_array_v<_Tp>) | |
83 | { | |
84 | for (auto& __x : *__location) | |
1e807763 | 85 | std::destroy_at(std::addressof(__x)); |
85f24114 JW |
86 | } |
87 | else | |
88 | __location->~_Tp(); | |
89 | } | |
90 | ||
8539c561 | 91 | #if __cpp_constexpr_dynamic_alloc // >= C++20 |
85f24114 | 92 | template<typename _Tp, typename... _Args> |
993deb3a JW |
93 | requires (!is_unbounded_array_v<_Tp>) |
94 | && requires { ::new((void*)0) _Tp(std::declval<_Args>()...); } | |
95 | constexpr _Tp* | |
85f24114 JW |
96 | construct_at(_Tp* __location, _Args&&... __args) |
97 | noexcept(noexcept(::new((void*)0) _Tp(std::declval<_Args>()...))) | |
993deb3a | 98 | { |
2eaae1bd | 99 | void* __loc = __location; |
993deb3a JW |
100 | // _GLIBCXX_RESOLVE_LIB_DEFECTS |
101 | // 3436. std::construct_at should support arrays | |
102 | if constexpr (is_array_v<_Tp>) | |
103 | { | |
104 | static_assert(sizeof...(_Args) == 0, "std::construct_at for array " | |
105 | "types must not use any arguments to initialize the " | |
106 | "array"); | |
107 | return ::new(__loc) _Tp[1](); | |
108 | } | |
109 | else | |
110 | return ::new(__loc) _Tp(std::forward<_Args>(__args)...); | |
111 | } | |
85f24114 JW |
112 | #endif // C++20 |
113 | #endif// C++17 | |
114 | ||
494fff4c | 115 | /** |
b0037845 PE |
116 | * Constructs an object in existing memory by invoking an allocated |
117 | * object's constructor with an initializer. | |
494fff4c | 118 | */ |
734f5023 | 119 | #if __cplusplus >= 201103L |
85f24114 | 120 | template<typename _Tp, typename... _Args> |
476f305b | 121 | _GLIBCXX20_CONSTEXPR |
162c40a4 | 122 | inline void |
85f24114 | 123 | _Construct(_Tp* __p, _Args&&... __args) |
476f305b | 124 | { |
8539c561 | 125 | #if __cpp_constexpr_dynamic_alloc // >= C++20 |
1e807763 | 126 | if (std::is_constant_evaluated()) |
476f305b JW |
127 | { |
128 | // Allow std::_Construct to be used in constant expressions. | |
129 | std::construct_at(__p, std::forward<_Args>(__args)...); | |
130 | return; | |
131 | } | |
132 | #endif | |
2eaae1bd | 133 | ::new(static_cast<void*>(__p)) _Tp(std::forward<_Args>(__args)...); |
476f305b | 134 | } |
55dd8445 | 135 | #else |
fe27aa8b | 136 | template<typename _T1, typename _T2> |
162c40a4 | 137 | inline void |
494fff4c | 138 | _Construct(_T1* __p, const _T2& __value) |
9dbaa948 PC |
139 | { |
140 | // _GLIBCXX_RESOLVE_LIB_DEFECTS | |
141 | // 402. wrong new expression in [some_]allocator::construct | |
162c40a4 | 142 | ::new(static_cast<void*>(__p)) _T1(__value); |
9dbaa948 | 143 | } |
fe27aa8b | 144 | #endif |
ed6814f7 | 145 | |
377f30c0 | 146 | template<typename _T1> |
3052b336 | 147 | _GLIBCXX26_CONSTEXPR |
377f30c0 VV |
148 | inline void |
149 | _Construct_novalue(_T1* __p) | |
2eaae1bd | 150 | { ::new(static_cast<void*>(__p)) _T1; } |
377f30c0 | 151 | |
85f24114 JW |
152 | template<typename _ForwardIterator> |
153 | _GLIBCXX20_CONSTEXPR void | |
154 | _Destroy(_ForwardIterator __first, _ForwardIterator __last); | |
155 | ||
da73f9de | 156 | /** |
da73f9de | 157 | * Destroy the object pointed to by a pointer type. |
da73f9de | 158 | */ |
d78e147a | 159 | template<typename _Tp> |
540218dd | 160 | _GLIBCXX14_CONSTEXPR inline void |
da73f9de | 161 | _Destroy(_Tp* __pointer) |
85f24114 | 162 | { |
8539c561 | 163 | #if __cpp_constexpr_dynamic_alloc // >= C++20 |
85f24114 JW |
164 | std::destroy_at(__pointer); |
165 | #else | |
166 | __pointer->~_Tp(); | |
167 | #endif | |
168 | } | |
da73f9de | 169 | |
1467409b JW |
170 | #pragma GCC diagnostic push |
171 | #pragma GCC diagnostic ignored "-Wc++17-extensions" // for if-constexpr | |
172 | ||
173 | #if __cplusplus < 201103L | |
cf0e6fff PC |
174 | template<bool> |
175 | struct _Destroy_aux | |
176 | { | |
177 | template<typename _ForwardIterator> | |
85f24114 JW |
178 | static _GLIBCXX20_CONSTEXPR void |
179 | __destroy(_ForwardIterator __first, _ForwardIterator __last) | |
cf0e6fff PC |
180 | { |
181 | for (; __first != __last; ++__first) | |
882b3d5c | 182 | std::_Destroy(std::__addressof(*__first)); |
cf0e6fff | 183 | } |
01789efa JW |
184 | |
185 | template<typename _ForwardIterator, typename _Size> | |
186 | static _GLIBCXX20_CONSTEXPR _ForwardIterator | |
187 | __destroy_n(_ForwardIterator __first, _Size __count) | |
188 | { | |
189 | for (; __count > 0; (void)++__first, --__count) | |
190 | std::_Destroy(std::__addressof(*__first)); | |
191 | return __first; | |
192 | } | |
cf0e6fff PC |
193 | }; |
194 | ||
195 | template<> | |
196 | struct _Destroy_aux<true> | |
197 | { | |
198 | template<typename _ForwardIterator> | |
199 | static void | |
200 | __destroy(_ForwardIterator, _ForwardIterator) { } | |
01789efa JW |
201 | |
202 | template<typename _ForwardIterator, typename _Size> | |
203 | static _ForwardIterator | |
204 | __destroy_n(_ForwardIterator __first, _Size __count) | |
205 | { | |
206 | std::advance(__first, __count); | |
207 | return __first; | |
208 | } | |
cf0e6fff | 209 | }; |
1467409b | 210 | #endif |
cf0e6fff | 211 | |
494fff4c SW |
212 | /** |
213 | * Destroy a range of objects. If the value_type of the object has | |
214 | * a trivial destructor, the compiler should optimize all of this | |
215 | * away, otherwise the objects' destructors must be invoked. | |
494fff4c | 216 | */ |
d78e147a | 217 | template<typename _ForwardIterator> |
85f24114 | 218 | _GLIBCXX20_CONSTEXPR inline void |
494fff4c SW |
219 | _Destroy(_ForwardIterator __first, _ForwardIterator __last) |
220 | { | |
221 | typedef typename iterator_traits<_ForwardIterator>::value_type | |
222 | _Value_type; | |
b26f45f0 | 223 | #if __cplusplus >= 201103L |
01789efa | 224 | if constexpr (!is_trivially_destructible<_Value_type>::value) |
1467409b | 225 | for (; __first != __last; ++__first) |
1e807763 | 226 | std::_Destroy(std::addressof(*__first)); |
8539c561 | 227 | #if __cpp_constexpr_dynamic_alloc // >= C++20 |
1e807763 | 228 | else if (std::is_constant_evaluated()) |
1467409b | 229 | for (; __first != __last; ++__first) |
1e807763 | 230 | std::destroy_at(std::addressof(*__first)); |
b26f45f0 | 231 | #endif |
1467409b | 232 | #else |
cf0e6fff PC |
233 | std::_Destroy_aux<__has_trivial_destructor(_Value_type)>:: |
234 | __destroy(__first, __last); | |
1467409b | 235 | #endif |
494fff4c | 236 | } |
1985f1cd | 237 | |
377f30c0 VV |
238 | /** |
239 | * Destroy a range of objects. If the value_type of the object has | |
240 | * a trivial destructor, the compiler should optimize all of this | |
241 | * away, otherwise the objects' destructors must be invoked. | |
242 | */ | |
243 | template<typename _ForwardIterator, typename _Size> | |
85f24114 | 244 | _GLIBCXX20_CONSTEXPR inline _ForwardIterator |
377f30c0 VV |
245 | _Destroy_n(_ForwardIterator __first, _Size __count) |
246 | { | |
247 | typedef typename iterator_traits<_ForwardIterator>::value_type | |
248 | _Value_type; | |
b26f45f0 | 249 | #if __cplusplus >= 201103L |
01789efa | 250 | if constexpr (!is_trivially_destructible<_Value_type>::value) |
1467409b | 251 | for (; __count > 0; (void)++__first, --__count) |
1e807763 | 252 | std::_Destroy(std::addressof(*__first)); |
8539c561 | 253 | #if __cpp_constexpr_dynamic_alloc // >= C++20 |
1e807763 | 254 | else if (std::is_constant_evaluated()) |
1467409b | 255 | for (; __count > 0; (void)++__first, --__count) |
1e807763 | 256 | std::destroy_at(std::addressof(*__first)); |
b26f45f0 | 257 | #endif |
1467409b JW |
258 | else |
259 | std::advance(__first, __count); | |
260 | return __first; | |
261 | #else | |
01789efa | 262 | return std::_Destroy_aux<__has_trivial_destructor(_Value_type)>:: |
377f30c0 | 263 | __destroy_n(__first, __count); |
1467409b | 264 | #endif |
377f30c0 | 265 | } |
1467409b | 266 | #pragma GCC diagnostic pop |
377f30c0 | 267 | |
8539c561 | 268 | #if __glibcxx_raw_memory_algorithms // >= C++17 |
b26f45f0 | 269 | template <typename _ForwardIterator> |
85f24114 | 270 | _GLIBCXX20_CONSTEXPR inline void |
b26f45f0 JW |
271 | destroy(_ForwardIterator __first, _ForwardIterator __last) |
272 | { | |
273 | std::_Destroy(__first, __last); | |
274 | } | |
275 | ||
276 | template <typename _ForwardIterator, typename _Size> | |
85f24114 | 277 | _GLIBCXX20_CONSTEXPR inline _ForwardIterator |
b26f45f0 JW |
278 | destroy_n(_ForwardIterator __first, _Size __count) |
279 | { | |
280 | return std::_Destroy_n(__first, __count); | |
281 | } | |
85f24114 | 282 | #endif // C++17 |
b26f45f0 | 283 | |
12ffa228 | 284 | _GLIBCXX_END_NAMESPACE_VERSION |
cd1e6665 | 285 | } // namespace std |
725dc051 | 286 | |
3d7c150e | 287 | #endif /* _STL_CONSTRUCT_H */ |