]>
Commit | Line | Data |
---|---|---|
52e86221 VV |
1 | // <any> -*- C++ -*- |
2 | ||
a5544970 | 3 | // Copyright (C) 2014-2019 Free Software Foundation, Inc. |
52e86221 VV |
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 | |
8 | // Free Software Foundation; either version 3, or (at your option) | |
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 | ||
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. | |
19 | ||
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/>. | |
24 | ||
25 | /** @file include/any | |
26 | * This is a Standard C++ Library header. | |
27 | */ | |
28 | ||
29 | #ifndef _GLIBCXX_ANY | |
30 | #define _GLIBCXX_ANY 1 | |
31 | ||
32 | #pragma GCC system_header | |
33 | ||
c6888c62 | 34 | #if __cplusplus >= 201703L |
52e86221 VV |
35 | |
36 | #include <typeinfo> | |
37 | #include <new> | |
38 | #include <utility> | |
39 | #include <type_traits> | |
40 | ||
41 | namespace std _GLIBCXX_VISIBILITY(default) | |
42 | { | |
43 | _GLIBCXX_BEGIN_NAMESPACE_VERSION | |
44 | ||
45 | /** | |
46 | * @addtogroup utilities | |
47 | * @{ | |
48 | */ | |
49 | ||
50 | /** | |
51 | * @brief Exception class thrown by a failed @c any_cast | |
52 | * @ingroup exceptions | |
53 | */ | |
54 | class bad_any_cast : public bad_cast | |
55 | { | |
56 | public: | |
57 | virtual const char* what() const noexcept { return "bad any_cast"; } | |
58 | }; | |
59 | ||
60 | [[gnu::noreturn]] inline void __throw_bad_any_cast() | |
61 | { | |
62 | #if __cpp_exceptions | |
63 | throw bad_any_cast{}; | |
64 | #else | |
65 | __builtin_abort(); | |
66 | #endif | |
67 | } | |
68 | ||
56a9eaf9 | 69 | #define __cpp_lib_any 201606L |
c6888c62 | 70 | |
52e86221 VV |
71 | /** |
72 | * @brief A type-safe container of any type. | |
73ebece3 | 73 | * |
52e86221 VV |
74 | * An @c any object's state is either empty or it stores a contained object |
75 | * of CopyConstructible type. | |
76 | */ | |
77 | class any | |
78 | { | |
79 | // Holds either pointer to a heap object or the contained object itself. | |
80 | union _Storage | |
81 | { | |
25a69162 | 82 | constexpr _Storage() : _M_ptr{nullptr} {} |
52e86221 VV |
83 | |
84 | // Prevent trivial copies of this type, buffer might hold a non-POD. | |
85 | _Storage(const _Storage&) = delete; | |
86 | _Storage& operator=(const _Storage&) = delete; | |
87 | ||
88 | void* _M_ptr; | |
89 | aligned_storage<sizeof(_M_ptr), alignof(void*)>::type _M_buffer; | |
90 | }; | |
91 | ||
92 | template<typename _Tp, typename _Safe = is_nothrow_move_constructible<_Tp>, | |
93 | bool _Fits = (sizeof(_Tp) <= sizeof(_Storage)) | |
94 | && (alignof(_Tp) <= alignof(_Storage))> | |
95 | using _Internal = std::integral_constant<bool, _Safe::value && _Fits>; | |
96 | ||
97 | template<typename _Tp> | |
98 | struct _Manager_internal; // uses small-object optimization | |
99 | ||
100 | template<typename _Tp> | |
101 | struct _Manager_external; // creates contained object on the heap | |
102 | ||
103 | template<typename _Tp> | |
104 | using _Manager = conditional_t<_Internal<_Tp>::value, | |
105 | _Manager_internal<_Tp>, | |
106 | _Manager_external<_Tp>>; | |
107 | ||
108 | template<typename _Tp, typename _Decayed = decay_t<_Tp>> | |
109 | using _Decay = enable_if_t<!is_same<_Decayed, any>::value, _Decayed>; | |
110 | ||
ca9e949f VV |
111 | /// Emplace with an object created from @p __args as the contained object. |
112 | template <typename _Tp, typename... _Args, | |
113 | typename _Mgr = _Manager<_Tp>> | |
114 | void __do_emplace(_Args&&... __args) | |
115 | { | |
116 | reset(); | |
ca9e949f | 117 | _Mgr::_S_create(_M_storage, std::forward<_Args>(__args)...); |
73ebece3 | 118 | _M_manager = &_Mgr::_S_manage; |
ca9e949f VV |
119 | } |
120 | ||
121 | /// Emplace with an object created from @p __il and @p __args as | |
122 | /// the contained object. | |
123 | template <typename _Tp, typename _Up, typename... _Args, | |
124 | typename _Mgr = _Manager<_Tp>> | |
125 | void __do_emplace(initializer_list<_Up> __il, _Args&&... __args) | |
126 | { | |
127 | reset(); | |
ca9e949f | 128 | _Mgr::_S_create(_M_storage, __il, std::forward<_Args>(__args)...); |
73ebece3 | 129 | _M_manager = &_Mgr::_S_manage; |
ca9e949f VV |
130 | } |
131 | ||
52e86221 VV |
132 | public: |
133 | // construct/destruct | |
134 | ||
135 | /// Default constructor, creates an empty object. | |
25a69162 | 136 | constexpr any() noexcept : _M_manager(nullptr) { } |
52e86221 VV |
137 | |
138 | /// Copy constructor, copies the state of @p __other | |
139 | any(const any& __other) | |
140 | { | |
25a69162 | 141 | if (!__other.has_value()) |
52e86221 VV |
142 | _M_manager = nullptr; |
143 | else | |
144 | { | |
145 | _Arg __arg; | |
146 | __arg._M_any = this; | |
147 | __other._M_manager(_Op_clone, &__other, &__arg); | |
148 | } | |
149 | } | |
150 | ||
151 | /** | |
152 | * @brief Move constructor, transfer the state from @p __other | |
153 | * | |
25a69162 | 154 | * @post @c !__other.has_value() (this postcondition is a GNU extension) |
52e86221 VV |
155 | */ |
156 | any(any&& __other) noexcept | |
157 | { | |
25a69162 | 158 | if (!__other.has_value()) |
52e86221 VV |
159 | _M_manager = nullptr; |
160 | else | |
161 | { | |
162 | _Arg __arg; | |
163 | __arg._M_any = this; | |
164 | __other._M_manager(_Op_xfer, &__other, &__arg); | |
165 | } | |
166 | } | |
167 | ||
ca9e949f VV |
168 | template <typename _Res, typename _Tp, typename... _Args> |
169 | using __any_constructible = | |
170 | enable_if<__and_<is_copy_constructible<_Tp>, | |
171 | is_constructible<_Tp, _Args...>>::value, | |
172 | _Res>; | |
173 | ||
25a69162 VV |
174 | template <typename _Tp, typename... _Args> |
175 | using __any_constructible_t = | |
ca9e949f | 176 | typename __any_constructible<bool, _Tp, _Args...>::type; |
25a69162 | 177 | |
52e86221 VV |
178 | /// Construct with a copy of @p __value as the contained object. |
179 | template <typename _ValueType, typename _Tp = _Decay<_ValueType>, | |
180 | typename _Mgr = _Manager<_Tp>, | |
5c578ae4 | 181 | __any_constructible_t<_Tp, _ValueType&&> = true, |
627a2f59 | 182 | enable_if_t<!__is_in_place_type<_Tp>::value, bool> = true> |
52e86221 VV |
183 | any(_ValueType&& __value) |
184 | : _M_manager(&_Mgr::_S_manage) | |
185 | { | |
186 | _Mgr::_S_create(_M_storage, std::forward<_ValueType>(__value)); | |
52e86221 VV |
187 | } |
188 | ||
189 | /// Construct with a copy of @p __value as the contained object. | |
190 | template <typename _ValueType, typename _Tp = _Decay<_ValueType>, | |
191 | typename _Mgr = _Manager<_Tp>, | |
25a69162 | 192 | enable_if_t<__and_<is_copy_constructible<_Tp>, |
5c578ae4 | 193 | __not_<is_constructible<_Tp, _ValueType&&>>, |
627a2f59 | 194 | __not_<__is_in_place_type<_Tp>>>::value, |
25a69162 | 195 | bool> = false> |
52e86221 VV |
196 | any(_ValueType&& __value) |
197 | : _M_manager(&_Mgr::_S_manage) | |
198 | { | |
199 | _Mgr::_S_create(_M_storage, __value); | |
52e86221 VV |
200 | } |
201 | ||
25a69162 | 202 | /// Construct with an object created from @p __args as the contained object. |
5c578ae4 VV |
203 | template <typename _ValueType, typename... _Args, |
204 | typename _Tp = _Decay<_ValueType>, | |
25a69162 VV |
205 | typename _Mgr = _Manager<_Tp>, |
206 | __any_constructible_t<_Tp, _Args&&...> = false> | |
1725d05d | 207 | explicit |
5c578ae4 | 208 | any(in_place_type_t<_ValueType>, _Args&&... __args) |
25a69162 VV |
209 | : _M_manager(&_Mgr::_S_manage) |
210 | { | |
211 | _Mgr::_S_create(_M_storage, std::forward<_Args>(__args)...); | |
212 | } | |
213 | ||
214 | /// Construct with an object created from @p __il and @p __args as | |
215 | /// the contained object. | |
5c578ae4 VV |
216 | template <typename _ValueType, typename _Up, typename... _Args, |
217 | typename _Tp = _Decay<_ValueType>, | |
25a69162 VV |
218 | typename _Mgr = _Manager<_Tp>, |
219 | __any_constructible_t<_Tp, initializer_list<_Up>, | |
220 | _Args&&...> = false> | |
1725d05d | 221 | explicit |
5c578ae4 VV |
222 | any(in_place_type_t<_ValueType>, |
223 | initializer_list<_Up> __il, _Args&&... __args) | |
25a69162 VV |
224 | : _M_manager(&_Mgr::_S_manage) |
225 | { | |
226 | _Mgr::_S_create(_M_storage, __il, std::forward<_Args>(__args)...); | |
227 | } | |
228 | ||
229 | /// Destructor, calls @c reset() | |
230 | ~any() { reset(); } | |
52e86221 VV |
231 | |
232 | // assignments | |
233 | ||
234 | /// Copy the state of another object. | |
235 | any& operator=(const any& __rhs) | |
236 | { | |
1725d05d | 237 | *this = any(__rhs); |
52e86221 VV |
238 | return *this; |
239 | } | |
240 | ||
241 | /** | |
242 | * @brief Move assignment operator | |
243 | * | |
25a69162 | 244 | * @post @c !__rhs.has_value() (not guaranteed for other implementations) |
52e86221 VV |
245 | */ |
246 | any& operator=(any&& __rhs) noexcept | |
247 | { | |
25a69162 VV |
248 | if (!__rhs.has_value()) |
249 | reset(); | |
52e86221 VV |
250 | else if (this != &__rhs) |
251 | { | |
1725d05d | 252 | reset(); |
52e86221 VV |
253 | _Arg __arg; |
254 | __arg._M_any = this; | |
255 | __rhs._M_manager(_Op_xfer, &__rhs, &__arg); | |
256 | } | |
257 | return *this; | |
258 | } | |
259 | ||
260 | /// Store a copy of @p __rhs as the contained object. | |
ca9e949f VV |
261 | template<typename _ValueType> |
262 | enable_if_t<is_copy_constructible<_Decay<_ValueType>>::value, any&> | |
52e86221 VV |
263 | operator=(_ValueType&& __rhs) |
264 | { | |
265 | *this = any(std::forward<_ValueType>(__rhs)); | |
266 | return *this; | |
267 | } | |
268 | ||
25a69162 | 269 | /// Emplace with an object created from @p __args as the contained object. |
ca9e949f | 270 | template <typename _ValueType, typename... _Args> |
df990182 | 271 | typename __any_constructible<_Decay<_ValueType>&, |
ca9e949f VV |
272 | _Decay<_ValueType>, _Args&&...>::type |
273 | emplace(_Args&&... __args) | |
25a69162 | 274 | { |
73ebece3 | 275 | __do_emplace<_Decay<_ValueType>>(std::forward<_Args>(__args)...); |
df990182 VV |
276 | any::_Arg __arg; |
277 | this->_M_manager(any::_Op_access, this, &__arg); | |
278 | return *static_cast<_Decay<_ValueType>*>(__arg._M_obj); | |
25a69162 VV |
279 | } |
280 | ||
281 | /// Emplace with an object created from @p __il and @p __args as | |
282 | /// the contained object. | |
ca9e949f | 283 | template <typename _ValueType, typename _Up, typename... _Args> |
df990182 | 284 | typename __any_constructible<_Decay<_ValueType>&, |
ca9e949f VV |
285 | _Decay<_ValueType>, |
286 | initializer_list<_Up>, | |
287 | _Args&&...>::type | |
288 | emplace(initializer_list<_Up> __il, _Args&&... __args) | |
25a69162 | 289 | { |
73ebece3 JW |
290 | __do_emplace<_Decay<_ValueType>, _Up>(__il, |
291 | std::forward<_Args>(__args)...); | |
df990182 VV |
292 | any::_Arg __arg; |
293 | this->_M_manager(any::_Op_access, this, &__arg); | |
294 | return *static_cast<_Decay<_ValueType>*>(__arg._M_obj); | |
25a69162 VV |
295 | } |
296 | ||
52e86221 VV |
297 | // modifiers |
298 | ||
299 | /// If not empty, destroy the contained object. | |
25a69162 | 300 | void reset() noexcept |
52e86221 | 301 | { |
25a69162 | 302 | if (has_value()) |
52e86221 VV |
303 | { |
304 | _M_manager(_Op_destroy, this, nullptr); | |
305 | _M_manager = nullptr; | |
306 | } | |
307 | } | |
308 | ||
309 | /// Exchange state with another object. | |
310 | void swap(any& __rhs) noexcept | |
311 | { | |
25a69162 | 312 | if (!has_value() && !__rhs.has_value()) |
52e86221 VV |
313 | return; |
314 | ||
25a69162 | 315 | if (has_value() && __rhs.has_value()) |
52e86221 VV |
316 | { |
317 | if (this == &__rhs) | |
318 | return; | |
319 | ||
320 | any __tmp; | |
321 | _Arg __arg; | |
322 | __arg._M_any = &__tmp; | |
323 | __rhs._M_manager(_Op_xfer, &__rhs, &__arg); | |
324 | __arg._M_any = &__rhs; | |
325 | _M_manager(_Op_xfer, this, &__arg); | |
326 | __arg._M_any = this; | |
327 | __tmp._M_manager(_Op_xfer, &__tmp, &__arg); | |
328 | } | |
329 | else | |
330 | { | |
25a69162 VV |
331 | any* __empty = !has_value() ? this : &__rhs; |
332 | any* __full = !has_value() ? &__rhs : this; | |
52e86221 VV |
333 | _Arg __arg; |
334 | __arg._M_any = __empty; | |
335 | __full->_M_manager(_Op_xfer, __full, &__arg); | |
336 | } | |
337 | } | |
338 | ||
339 | // observers | |
340 | ||
341 | /// Reports whether there is a contained object or not. | |
25a69162 | 342 | bool has_value() const noexcept { return _M_manager != nullptr; } |
52e86221 VV |
343 | |
344 | #if __cpp_rtti | |
345 | /// The @c typeid of the contained object, or @c typeid(void) if empty. | |
346 | const type_info& type() const noexcept | |
347 | { | |
25a69162 | 348 | if (!has_value()) |
52e86221 VV |
349 | return typeid(void); |
350 | _Arg __arg; | |
351 | _M_manager(_Op_get_type_info, this, &__arg); | |
352 | return *__arg._M_typeinfo; | |
353 | } | |
354 | #endif | |
355 | ||
356 | template<typename _Tp> | |
357 | static constexpr bool __is_valid_cast() | |
358 | { return __or_<is_reference<_Tp>, is_copy_constructible<_Tp>>::value; } | |
359 | ||
360 | private: | |
361 | enum _Op { | |
362 | _Op_access, _Op_get_type_info, _Op_clone, _Op_destroy, _Op_xfer | |
363 | }; | |
364 | ||
365 | union _Arg | |
366 | { | |
367 | void* _M_obj; | |
368 | const std::type_info* _M_typeinfo; | |
369 | any* _M_any; | |
370 | }; | |
371 | ||
372 | void (*_M_manager)(_Op, const any*, _Arg*); | |
373 | _Storage _M_storage; | |
374 | ||
375 | template<typename _Tp> | |
376 | friend void* __any_caster(const any* __any); | |
377 | ||
378 | // Manage in-place contained object. | |
379 | template<typename _Tp> | |
380 | struct _Manager_internal | |
381 | { | |
382 | static void | |
383 | _S_manage(_Op __which, const any* __anyp, _Arg* __arg); | |
384 | ||
385 | template<typename _Up> | |
386 | static void | |
387 | _S_create(_Storage& __storage, _Up&& __value) | |
388 | { | |
389 | void* __addr = &__storage._M_buffer; | |
390 | ::new (__addr) _Tp(std::forward<_Up>(__value)); | |
391 | } | |
25a69162 VV |
392 | |
393 | template<typename... _Args> | |
394 | static void | |
395 | _S_create(_Storage& __storage, _Args&&... __args) | |
396 | { | |
397 | void* __addr = &__storage._M_buffer; | |
398 | ::new (__addr) _Tp(std::forward<_Args>(__args)...); | |
399 | } | |
52e86221 VV |
400 | }; |
401 | ||
402 | // Manage external contained object. | |
403 | template<typename _Tp> | |
404 | struct _Manager_external | |
405 | { | |
406 | static void | |
407 | _S_manage(_Op __which, const any* __anyp, _Arg* __arg); | |
408 | ||
409 | template<typename _Up> | |
410 | static void | |
411 | _S_create(_Storage& __storage, _Up&& __value) | |
412 | { | |
413 | __storage._M_ptr = new _Tp(std::forward<_Up>(__value)); | |
414 | } | |
25a69162 VV |
415 | template<typename... _Args> |
416 | static void | |
417 | _S_create(_Storage& __storage, _Args&&... __args) | |
418 | { | |
419 | __storage._M_ptr = new _Tp(std::forward<_Args>(__args)...); | |
420 | } | |
52e86221 VV |
421 | }; |
422 | }; | |
423 | ||
424 | /// Exchange the states of two @c any objects. | |
425 | inline void swap(any& __x, any& __y) noexcept { __x.swap(__y); } | |
426 | ||
25a69162 VV |
427 | /// Create an any holding a @c _Tp constructed from @c __args. |
428 | template <typename _Tp, typename... _Args> | |
429 | any make_any(_Args&&... __args) | |
430 | { | |
627a2f59 | 431 | return any(in_place_type<_Tp>, std::forward<_Args>(__args)...); |
25a69162 VV |
432 | } |
433 | ||
434 | /// Create an any holding a @c _Tp constructed from @c __il and @c __args. | |
435 | template <typename _Tp, typename _Up, typename... _Args> | |
436 | any make_any(initializer_list<_Up> __il, _Args&&... __args) | |
437 | { | |
627a2f59 | 438 | return any(in_place_type<_Tp>, __il, std::forward<_Args>(__args)...); |
25a69162 VV |
439 | } |
440 | ||
52e86221 VV |
441 | /** |
442 | * @brief Access the contained object. | |
443 | * | |
444 | * @tparam _ValueType A const-reference or CopyConstructible type. | |
445 | * @param __any The object to access. | |
446 | * @return The contained object. | |
447 | * @throw bad_any_cast If <code> | |
448 | * __any.type() != typeid(remove_reference_t<_ValueType>) | |
449 | * </code> | |
450 | */ | |
451 | template<typename _ValueType> | |
452 | inline _ValueType any_cast(const any& __any) | |
453 | { | |
6791489e | 454 | using _Up = __remove_cvref_t<_ValueType>; |
52e86221 VV |
455 | static_assert(any::__is_valid_cast<_ValueType>(), |
456 | "Template argument must be a reference or CopyConstructible type"); | |
23c3a059 VV |
457 | static_assert(is_constructible_v<_ValueType, const _Up&>, |
458 | "Template argument must be constructible from a const value."); | |
459 | auto __p = any_cast<_Up>(&__any); | |
52e86221 | 460 | if (__p) |
62549523 | 461 | return static_cast<_ValueType>(*__p); |
52e86221 VV |
462 | __throw_bad_any_cast(); |
463 | } | |
464 | ||
465 | /** | |
466 | * @brief Access the contained object. | |
467 | * | |
468 | * @tparam _ValueType A reference or CopyConstructible type. | |
469 | * @param __any The object to access. | |
470 | * @return The contained object. | |
471 | * @throw bad_any_cast If <code> | |
472 | * __any.type() != typeid(remove_reference_t<_ValueType>) | |
473 | * </code> | |
474 | * | |
475 | * @{ | |
476 | */ | |
477 | template<typename _ValueType> | |
478 | inline _ValueType any_cast(any& __any) | |
479 | { | |
6791489e | 480 | using _Up = __remove_cvref_t<_ValueType>; |
52e86221 VV |
481 | static_assert(any::__is_valid_cast<_ValueType>(), |
482 | "Template argument must be a reference or CopyConstructible type"); | |
23c3a059 VV |
483 | static_assert(is_constructible_v<_ValueType, _Up&>, |
484 | "Template argument must be constructible from an lvalue."); | |
485 | auto __p = any_cast<_Up>(&__any); | |
52e86221 | 486 | if (__p) |
62549523 | 487 | return static_cast<_ValueType>(*__p); |
52e86221 VV |
488 | __throw_bad_any_cast(); |
489 | } | |
490 | ||
23c3a059 | 491 | template<typename _ValueType> |
52e86221 VV |
492 | inline _ValueType any_cast(any&& __any) |
493 | { | |
6791489e | 494 | using _Up = __remove_cvref_t<_ValueType>; |
52e86221 VV |
495 | static_assert(any::__is_valid_cast<_ValueType>(), |
496 | "Template argument must be a reference or CopyConstructible type"); | |
23c3a059 VV |
497 | static_assert(is_constructible_v<_ValueType, _Up>, |
498 | "Template argument must be constructible from an rvalue."); | |
499 | auto __p = any_cast<_Up>(&__any); | |
52e86221 | 500 | if (__p) |
62549523 | 501 | return static_cast<_ValueType>(std::move(*__p)); |
52e86221 VV |
502 | __throw_bad_any_cast(); |
503 | } | |
504 | // @} | |
505 | ||
506 | template<typename _Tp> | |
507 | void* __any_caster(const any* __any) | |
508 | { | |
38a9e5a6 JW |
509 | if constexpr (is_copy_constructible_v<decay_t<_Tp>>) |
510 | { | |
511 | if (__any->_M_manager == &any::_Manager<decay_t<_Tp>>::_S_manage) | |
512 | { | |
513 | any::_Arg __arg; | |
514 | __any->_M_manager(any::_Op_access, __any, &__arg); | |
515 | return __arg._M_obj; | |
516 | } | |
517 | } | |
518 | return nullptr; | |
52e86221 VV |
519 | } |
520 | ||
521 | /** | |
522 | * @brief Access the contained object. | |
523 | * | |
524 | * @tparam _ValueType The type of the contained object. | |
525 | * @param __any A pointer to the object to access. | |
526 | * @return The address of the contained object if <code> | |
527 | * __any != nullptr && __any.type() == typeid(_ValueType) | |
528 | * </code>, otherwise a null pointer. | |
529 | * | |
530 | * @{ | |
531 | */ | |
532 | template<typename _ValueType> | |
533 | inline const _ValueType* any_cast(const any* __any) noexcept | |
534 | { | |
f9bfdfa2 JW |
535 | if constexpr (is_object_v<_ValueType>) |
536 | if (__any) | |
537 | return static_cast<_ValueType*>(__any_caster<_ValueType>(__any)); | |
52e86221 VV |
538 | return nullptr; |
539 | } | |
540 | ||
541 | template<typename _ValueType> | |
542 | inline _ValueType* any_cast(any* __any) noexcept | |
543 | { | |
f9bfdfa2 JW |
544 | if constexpr (is_object_v<_ValueType>) |
545 | if (__any) | |
546 | return static_cast<_ValueType*>(__any_caster<_ValueType>(__any)); | |
52e86221 VV |
547 | return nullptr; |
548 | } | |
549 | // @} | |
550 | ||
551 | template<typename _Tp> | |
552 | void | |
553 | any::_Manager_internal<_Tp>:: | |
554 | _S_manage(_Op __which, const any* __any, _Arg* __arg) | |
555 | { | |
556 | // The contained object is in _M_storage._M_buffer | |
557 | auto __ptr = reinterpret_cast<const _Tp*>(&__any->_M_storage._M_buffer); | |
558 | switch (__which) | |
559 | { | |
560 | case _Op_access: | |
561 | __arg->_M_obj = const_cast<_Tp*>(__ptr); | |
562 | break; | |
563 | case _Op_get_type_info: | |
564 | #if __cpp_rtti | |
565 | __arg->_M_typeinfo = &typeid(_Tp); | |
566 | #endif | |
567 | break; | |
568 | case _Op_clone: | |
569 | ::new(&__arg->_M_any->_M_storage._M_buffer) _Tp(*__ptr); | |
570 | __arg->_M_any->_M_manager = __any->_M_manager; | |
571 | break; | |
572 | case _Op_destroy: | |
573 | __ptr->~_Tp(); | |
574 | break; | |
575 | case _Op_xfer: | |
1725d05d VV |
576 | ::new(&__arg->_M_any->_M_storage._M_buffer) _Tp |
577 | (std::move(*const_cast<_Tp*>(__ptr))); | |
52e86221 VV |
578 | __ptr->~_Tp(); |
579 | __arg->_M_any->_M_manager = __any->_M_manager; | |
580 | const_cast<any*>(__any)->_M_manager = nullptr; | |
581 | break; | |
582 | } | |
583 | } | |
584 | ||
585 | template<typename _Tp> | |
586 | void | |
587 | any::_Manager_external<_Tp>:: | |
588 | _S_manage(_Op __which, const any* __any, _Arg* __arg) | |
589 | { | |
590 | // The contained object is *_M_storage._M_ptr | |
591 | auto __ptr = static_cast<const _Tp*>(__any->_M_storage._M_ptr); | |
592 | switch (__which) | |
593 | { | |
594 | case _Op_access: | |
595 | __arg->_M_obj = const_cast<_Tp*>(__ptr); | |
596 | break; | |
597 | case _Op_get_type_info: | |
598 | #if __cpp_rtti | |
599 | __arg->_M_typeinfo = &typeid(_Tp); | |
600 | #endif | |
601 | break; | |
602 | case _Op_clone: | |
603 | __arg->_M_any->_M_storage._M_ptr = new _Tp(*__ptr); | |
604 | __arg->_M_any->_M_manager = __any->_M_manager; | |
605 | break; | |
606 | case _Op_destroy: | |
607 | delete __ptr; | |
608 | break; | |
609 | case _Op_xfer: | |
610 | __arg->_M_any->_M_storage._M_ptr = __any->_M_storage._M_ptr; | |
611 | __arg->_M_any->_M_manager = __any->_M_manager; | |
612 | const_cast<any*>(__any)->_M_manager = nullptr; | |
613 | break; | |
614 | } | |
615 | } | |
616 | ||
617 | /// @} | |
73ebece3 | 618 | |
10f26de9 JW |
619 | namespace __detail::__variant |
620 | { | |
621 | template<typename> struct _Never_valueless_alt; // see <variant> | |
622 | ||
623 | // Provide the strong exception-safety guarantee when emplacing an | |
624 | // any into a variant. | |
625 | template<> | |
626 | struct _Never_valueless_alt<std::any> | |
627 | : std::true_type | |
628 | { }; | |
629 | } // namespace __detail::__variant | |
630 | ||
52e86221 VV |
631 | _GLIBCXX_END_NAMESPACE_VERSION |
632 | } // namespace std | |
633 | ||
10f26de9 | 634 | #endif // C++17 |
52e86221 | 635 | #endif // _GLIBCXX_ANY |