| 1 |
// <any> -*- C++ -*- |
| 2 |
|
| 3 |
// Copyright (C) 2014-2021 Free Software Foundation, Inc. |
| 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 |
|
| 34 |
#if __cplusplus >= 201703L |
| 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 |
|
| 69 |
#define __cpp_lib_any 201606L |
| 70 |
|
| 71 |
/** |
| 72 |
* @brief A type-safe container of any type. |
| 73 |
* |
| 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 |
{ |
| 82 |
constexpr _Storage() : _M_ptr{nullptr} {} |
| 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 _VTp = decay_t<_Tp>> |
| 109 |
using _Decay_if_not_any = enable_if_t<!is_same_v<_VTp, any>, _VTp>; |
| 110 |
|
| 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(); |
| 117 |
_Mgr::_S_create(_M_storage, std::forward<_Args>(__args)...); |
| 118 |
_M_manager = &_Mgr::_S_manage; |
| 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(); |
| 128 |
_Mgr::_S_create(_M_storage, __il, std::forward<_Args>(__args)...); |
| 129 |
_M_manager = &_Mgr::_S_manage; |
| 130 |
} |
| 131 |
|
| 132 |
template <typename _Res, typename _Tp, typename... _Args> |
| 133 |
using __any_constructible |
| 134 |
= enable_if<__and_<is_copy_constructible<_Tp>, |
| 135 |
is_constructible<_Tp, _Args...>>::value, |
| 136 |
_Res>; |
| 137 |
|
| 138 |
template <typename _Tp, typename... _Args> |
| 139 |
using __any_constructible_t |
| 140 |
= typename __any_constructible<bool, _Tp, _Args...>::type; |
| 141 |
|
| 142 |
template<typename _VTp, typename... _Args> |
| 143 |
using __emplace_t |
| 144 |
= typename __any_constructible<_VTp&, _VTp, _Args...>::type; |
| 145 |
|
| 146 |
public: |
| 147 |
// construct/destruct |
| 148 |
|
| 149 |
/// Default constructor, creates an empty object. |
| 150 |
constexpr any() noexcept : _M_manager(nullptr) { } |
| 151 |
|
| 152 |
/// Copy constructor, copies the state of @p __other |
| 153 |
any(const any& __other) |
| 154 |
{ |
| 155 |
if (!__other.has_value()) |
| 156 |
_M_manager = nullptr; |
| 157 |
else |
| 158 |
{ |
| 159 |
_Arg __arg; |
| 160 |
__arg._M_any = this; |
| 161 |
__other._M_manager(_Op_clone, &__other, &__arg); |
| 162 |
} |
| 163 |
} |
| 164 |
|
| 165 |
/** |
| 166 |
* @brief Move constructor, transfer the state from @p __other |
| 167 |
* |
| 168 |
* @post @c !__other.has_value() (this postcondition is a GNU extension) |
| 169 |
*/ |
| 170 |
any(any&& __other) noexcept |
| 171 |
{ |
| 172 |
if (!__other.has_value()) |
| 173 |
_M_manager = nullptr; |
| 174 |
else |
| 175 |
{ |
| 176 |
_Arg __arg; |
| 177 |
__arg._M_any = this; |
| 178 |
__other._M_manager(_Op_xfer, &__other, &__arg); |
| 179 |
} |
| 180 |
} |
| 181 |
|
| 182 |
/// Construct with a copy of @p __value as the contained object. |
| 183 |
template <typename _Tp, typename _VTp = _Decay_if_not_any<_Tp>, |
| 184 |
typename _Mgr = _Manager<_VTp>, |
| 185 |
enable_if_t<is_copy_constructible<_VTp>::value |
| 186 |
&& !__is_in_place_type<_VTp>::value, bool> = true> |
| 187 |
any(_Tp&& __value) |
| 188 |
: _M_manager(&_Mgr::_S_manage) |
| 189 |
{ |
| 190 |
_Mgr::_S_create(_M_storage, std::forward<_Tp>(__value)); |
| 191 |
} |
| 192 |
|
| 193 |
/// Construct with an object created from @p __args as the contained object. |
| 194 |
template <typename _Tp, typename... _Args, typename _VTp = decay_t<_Tp>, |
| 195 |
typename _Mgr = _Manager<_VTp>, |
| 196 |
__any_constructible_t<_VTp, _Args&&...> = false> |
| 197 |
explicit |
| 198 |
any(in_place_type_t<_Tp>, _Args&&... __args) |
| 199 |
: _M_manager(&_Mgr::_S_manage) |
| 200 |
{ |
| 201 |
_Mgr::_S_create(_M_storage, std::forward<_Args>(__args)...); |
| 202 |
} |
| 203 |
|
| 204 |
/// Construct with an object created from @p __il and @p __args as |
| 205 |
/// the contained object. |
| 206 |
template <typename _Tp, typename _Up, typename... _Args, |
| 207 |
typename _VTp = decay_t<_Tp>, typename _Mgr = _Manager<_VTp>, |
| 208 |
__any_constructible_t<_VTp, initializer_list<_Up>&, |
| 209 |
_Args&&...> = false> |
| 210 |
explicit |
| 211 |
any(in_place_type_t<_Tp>, initializer_list<_Up> __il, _Args&&... __args) |
| 212 |
: _M_manager(&_Mgr::_S_manage) |
| 213 |
{ |
| 214 |
_Mgr::_S_create(_M_storage, __il, std::forward<_Args>(__args)...); |
| 215 |
} |
| 216 |
|
| 217 |
/// Destructor, calls @c reset() |
| 218 |
~any() { reset(); } |
| 219 |
|
| 220 |
// assignments |
| 221 |
|
| 222 |
/// Copy the state of another object. |
| 223 |
any& |
| 224 |
operator=(const any& __rhs) |
| 225 |
{ |
| 226 |
*this = any(__rhs); |
| 227 |
return *this; |
| 228 |
} |
| 229 |
|
| 230 |
/** |
| 231 |
* @brief Move assignment operator |
| 232 |
* |
| 233 |
* @post @c !__rhs.has_value() (not guaranteed for other implementations) |
| 234 |
*/ |
| 235 |
any& |
| 236 |
operator=(any&& __rhs) noexcept |
| 237 |
{ |
| 238 |
if (!__rhs.has_value()) |
| 239 |
reset(); |
| 240 |
else if (this != &__rhs) |
| 241 |
{ |
| 242 |
reset(); |
| 243 |
_Arg __arg; |
| 244 |
__arg._M_any = this; |
| 245 |
__rhs._M_manager(_Op_xfer, &__rhs, &__arg); |
| 246 |
} |
| 247 |
return *this; |
| 248 |
} |
| 249 |
|
| 250 |
/// Store a copy of @p __rhs as the contained object. |
| 251 |
template<typename _Tp> |
| 252 |
enable_if_t<is_copy_constructible<_Decay_if_not_any<_Tp>>::value, any&> |
| 253 |
operator=(_Tp&& __rhs) |
| 254 |
{ |
| 255 |
*this = any(std::forward<_Tp>(__rhs)); |
| 256 |
return *this; |
| 257 |
} |
| 258 |
|
| 259 |
/// Emplace with an object created from @p __args as the contained object. |
| 260 |
template <typename _Tp, typename... _Args> |
| 261 |
__emplace_t<decay_t<_Tp>, _Args...> |
| 262 |
emplace(_Args&&... __args) |
| 263 |
{ |
| 264 |
using _VTp = decay_t<_Tp>; |
| 265 |
__do_emplace<_VTp>(std::forward<_Args>(__args)...); |
| 266 |
any::_Arg __arg; |
| 267 |
this->_M_manager(any::_Op_access, this, &__arg); |
| 268 |
return *static_cast<_VTp*>(__arg._M_obj); |
| 269 |
} |
| 270 |
|
| 271 |
/// Emplace with an object created from @p __il and @p __args as |
| 272 |
/// the contained object. |
| 273 |
template <typename _Tp, typename _Up, typename... _Args> |
| 274 |
__emplace_t<decay_t<_Tp>, initializer_list<_Up>&, _Args&&...> |
| 275 |
emplace(initializer_list<_Up> __il, _Args&&... __args) |
| 276 |
{ |
| 277 |
using _VTp = decay_t<_Tp>; |
| 278 |
__do_emplace<_VTp, _Up>(__il, std::forward<_Args>(__args)...); |
| 279 |
any::_Arg __arg; |
| 280 |
this->_M_manager(any::_Op_access, this, &__arg); |
| 281 |
return *static_cast<_VTp*>(__arg._M_obj); |
| 282 |
} |
| 283 |
|
| 284 |
// modifiers |
| 285 |
|
| 286 |
/// If not empty, destroy the contained object. |
| 287 |
void reset() noexcept |
| 288 |
{ |
| 289 |
if (has_value()) |
| 290 |
{ |
| 291 |
_M_manager(_Op_destroy, this, nullptr); |
| 292 |
_M_manager = nullptr; |
| 293 |
} |
| 294 |
} |
| 295 |
|
| 296 |
/// Exchange state with another object. |
| 297 |
void swap(any& __rhs) noexcept |
| 298 |
{ |
| 299 |
if (!has_value() && !__rhs.has_value()) |
| 300 |
return; |
| 301 |
|
| 302 |
if (has_value() && __rhs.has_value()) |
| 303 |
{ |
| 304 |
if (this == &__rhs) |
| 305 |
return; |
| 306 |
|
| 307 |
any __tmp; |
| 308 |
_Arg __arg; |
| 309 |
__arg._M_any = &__tmp; |
| 310 |
__rhs._M_manager(_Op_xfer, &__rhs, &__arg); |
| 311 |
__arg._M_any = &__rhs; |
| 312 |
_M_manager(_Op_xfer, this, &__arg); |
| 313 |
__arg._M_any = this; |
| 314 |
__tmp._M_manager(_Op_xfer, &__tmp, &__arg); |
| 315 |
} |
| 316 |
else |
| 317 |
{ |
| 318 |
any* __empty = !has_value() ? this : &__rhs; |
| 319 |
any* __full = !has_value() ? &__rhs : this; |
| 320 |
_Arg __arg; |
| 321 |
__arg._M_any = __empty; |
| 322 |
__full->_M_manager(_Op_xfer, __full, &__arg); |
| 323 |
} |
| 324 |
} |
| 325 |
|
| 326 |
// observers |
| 327 |
|
| 328 |
/// Reports whether there is a contained object or not. |
| 329 |
bool has_value() const noexcept { return _M_manager != nullptr; } |
| 330 |
|
| 331 |
#if __cpp_rtti |
| 332 |
/// The @c typeid of the contained object, or @c typeid(void) if empty. |
| 333 |
const type_info& type() const noexcept |
| 334 |
{ |
| 335 |
if (!has_value()) |
| 336 |
return typeid(void); |
| 337 |
_Arg __arg; |
| 338 |
_M_manager(_Op_get_type_info, this, &__arg); |
| 339 |
return *__arg._M_typeinfo; |
| 340 |
} |
| 341 |
#endif |
| 342 |
|
| 343 |
template<typename _Tp> |
| 344 |
static constexpr bool __is_valid_cast() |
| 345 |
{ return __or_<is_reference<_Tp>, is_copy_constructible<_Tp>>::value; } |
| 346 |
|
| 347 |
private: |
| 348 |
enum _Op { |
| 349 |
_Op_access, _Op_get_type_info, _Op_clone, _Op_destroy, _Op_xfer |
| 350 |
}; |
| 351 |
|
| 352 |
union _Arg |
| 353 |
{ |
| 354 |
void* _M_obj; |
| 355 |
const std::type_info* _M_typeinfo; |
| 356 |
any* _M_any; |
| 357 |
}; |
| 358 |
|
| 359 |
void (*_M_manager)(_Op, const any*, _Arg*); |
| 360 |
_Storage _M_storage; |
| 361 |
|
| 362 |
template<typename _Tp> |
| 363 |
friend void* __any_caster(const any* __any); |
| 364 |
|
| 365 |
// Manage in-place contained object. |
| 366 |
template<typename _Tp> |
| 367 |
struct _Manager_internal |
| 368 |
{ |
| 369 |
static void |
| 370 |
_S_manage(_Op __which, const any* __anyp, _Arg* __arg); |
| 371 |
|
| 372 |
template<typename _Up> |
| 373 |
static void |
| 374 |
_S_create(_Storage& __storage, _Up&& __value) |
| 375 |
{ |
| 376 |
void* __addr = &__storage._M_buffer; |
| 377 |
::new (__addr) _Tp(std::forward<_Up>(__value)); |
| 378 |
} |
| 379 |
|
| 380 |
template<typename... _Args> |
| 381 |
static void |
| 382 |
_S_create(_Storage& __storage, _Args&&... __args) |
| 383 |
{ |
| 384 |
void* __addr = &__storage._M_buffer; |
| 385 |
::new (__addr) _Tp(std::forward<_Args>(__args)...); |
| 386 |
} |
| 387 |
}; |
| 388 |
|
| 389 |
// Manage external contained object. |
| 390 |
template<typename _Tp> |
| 391 |
struct _Manager_external |
| 392 |
{ |
| 393 |
static void |
| 394 |
_S_manage(_Op __which, const any* __anyp, _Arg* __arg); |
| 395 |
|
| 396 |
template<typename _Up> |
| 397 |
static void |
| 398 |
_S_create(_Storage& __storage, _Up&& __value) |
| 399 |
{ |
| 400 |
__storage._M_ptr = new _Tp(std::forward<_Up>(__value)); |
| 401 |
} |
| 402 |
template<typename... _Args> |
| 403 |
static void |
| 404 |
_S_create(_Storage& __storage, _Args&&... __args) |
| 405 |
{ |
| 406 |
__storage._M_ptr = new _Tp(std::forward<_Args>(__args)...); |
| 407 |
} |
| 408 |
}; |
| 409 |
}; |
| 410 |
|
| 411 |
/// Exchange the states of two @c any objects. |
| 412 |
inline void swap(any& __x, any& __y) noexcept { __x.swap(__y); } |
| 413 |
|
| 414 |
/// Create an any holding a @c _Tp constructed from @c __args. |
| 415 |
template <typename _Tp, typename... _Args> |
| 416 |
any make_any(_Args&&... __args) |
| 417 |
{ |
| 418 |
return any(in_place_type<_Tp>, std::forward<_Args>(__args)...); |
| 419 |
} |
| 420 |
|
| 421 |
/// Create an any holding a @c _Tp constructed from @c __il and @c __args. |
| 422 |
template <typename _Tp, typename _Up, typename... _Args> |
| 423 |
any make_any(initializer_list<_Up> __il, _Args&&... __args) |
| 424 |
{ |
| 425 |
return any(in_place_type<_Tp>, __il, std::forward<_Args>(__args)...); |
| 426 |
} |
| 427 |
|
| 428 |
/** |
| 429 |
* @brief Access the contained object. |
| 430 |
* |
| 431 |
* @tparam _ValueType A const-reference or CopyConstructible type. |
| 432 |
* @param __any The object to access. |
| 433 |
* @return The contained object. |
| 434 |
* @throw bad_any_cast If <code> |
| 435 |
* __any.type() != typeid(remove_reference_t<_ValueType>) |
| 436 |
* </code> |
| 437 |
*/ |
| 438 |
template<typename _ValueType> |
| 439 |
inline _ValueType any_cast(const any& __any) |
| 440 |
{ |
| 441 |
using _Up = __remove_cvref_t<_ValueType>; |
| 442 |
static_assert(any::__is_valid_cast<_ValueType>(), |
| 443 |
"Template argument must be a reference or CopyConstructible type"); |
| 444 |
static_assert(is_constructible_v<_ValueType, const _Up&>, |
| 445 |
"Template argument must be constructible from a const value."); |
| 446 |
auto __p = any_cast<_Up>(&__any); |
| 447 |
if (__p) |
| 448 |
return static_cast<_ValueType>(*__p); |
| 449 |
__throw_bad_any_cast(); |
| 450 |
} |
| 451 |
|
| 452 |
/** |
| 453 |
* @brief Access the contained object. |
| 454 |
* |
| 455 |
* @tparam _ValueType A reference or CopyConstructible type. |
| 456 |
* @param __any The object to access. |
| 457 |
* @return The contained object. |
| 458 |
* @throw bad_any_cast If <code> |
| 459 |
* __any.type() != typeid(remove_reference_t<_ValueType>) |
| 460 |
* </code> |
| 461 |
* |
| 462 |
* @{ |
| 463 |
*/ |
| 464 |
template<typename _ValueType> |
| 465 |
inline _ValueType any_cast(any& __any) |
| 466 |
{ |
| 467 |
using _Up = __remove_cvref_t<_ValueType>; |
| 468 |
static_assert(any::__is_valid_cast<_ValueType>(), |
| 469 |
"Template argument must be a reference or CopyConstructible type"); |
| 470 |
static_assert(is_constructible_v<_ValueType, _Up&>, |
| 471 |
"Template argument must be constructible from an lvalue."); |
| 472 |
auto __p = any_cast<_Up>(&__any); |
| 473 |
if (__p) |
| 474 |
return static_cast<_ValueType>(*__p); |
| 475 |
__throw_bad_any_cast(); |
| 476 |
} |
| 477 |
|
| 478 |
template<typename _ValueType> |
| 479 |
inline _ValueType any_cast(any&& __any) |
| 480 |
{ |
| 481 |
using _Up = __remove_cvref_t<_ValueType>; |
| 482 |
static_assert(any::__is_valid_cast<_ValueType>(), |
| 483 |
"Template argument must be a reference or CopyConstructible type"); |
| 484 |
static_assert(is_constructible_v<_ValueType, _Up>, |
| 485 |
"Template argument must be constructible from an rvalue."); |
| 486 |
auto __p = any_cast<_Up>(&__any); |
| 487 |
if (__p) |
| 488 |
return static_cast<_ValueType>(std::move(*__p)); |
| 489 |
__throw_bad_any_cast(); |
| 490 |
} |
| 491 |
/// @} |
| 492 |
|
| 493 |
/// @cond undocumented |
| 494 |
template<typename _Tp> |
| 495 |
void* __any_caster(const any* __any) |
| 496 |
{ |
| 497 |
// any_cast<T> returns non-null if __any->type() == typeid(T) and |
| 498 |
// typeid(T) ignores cv-qualifiers so remove them: |
| 499 |
using _Up = remove_cv_t<_Tp>; |
| 500 |
// The contained value has a decayed type, so if decay_t<U> is not U, |
| 501 |
// then it's not possible to have a contained value of type U: |
| 502 |
if constexpr (!is_same_v<decay_t<_Up>, _Up>) |
| 503 |
return nullptr; |
| 504 |
// Only copy constructible types can be used for contained values: |
| 505 |
else if constexpr (!is_copy_constructible_v<_Up>) |
| 506 |
return nullptr; |
| 507 |
// First try comparing function addresses, which works without RTTI |
| 508 |
else if (__any->_M_manager == &any::_Manager<_Up>::_S_manage |
| 509 |
#if __cpp_rtti |
| 510 |
|| __any->type() == typeid(_Tp) |
| 511 |
#endif |
| 512 |
) |
| 513 |
{ |
| 514 |
any::_Arg __arg; |
| 515 |
__any->_M_manager(any::_Op_access, __any, &__arg); |
| 516 |
return __arg._M_obj; |
| 517 |
} |
| 518 |
return nullptr; |
| 519 |
} |
| 520 |
/// @endcond |
| 521 |
|
| 522 |
/** |
| 523 |
* @brief Access the contained object. |
| 524 |
* |
| 525 |
* @tparam _ValueType The type of the contained object. |
| 526 |
* @param __any A pointer to the object to access. |
| 527 |
* @return The address of the contained object if <code> |
| 528 |
* __any != nullptr && __any.type() == typeid(_ValueType) |
| 529 |
* </code>, otherwise a null pointer. |
| 530 |
* |
| 531 |
* @{ |
| 532 |
*/ |
| 533 |
template<typename _ValueType> |
| 534 |
inline const _ValueType* any_cast(const any* __any) noexcept |
| 535 |
{ |
| 536 |
if constexpr (is_object_v<_ValueType>) |
| 537 |
if (__any) |
| 538 |
return static_cast<_ValueType*>(__any_caster<_ValueType>(__any)); |
| 539 |
return nullptr; |
| 540 |
} |
| 541 |
|
| 542 |
template<typename _ValueType> |
| 543 |
inline _ValueType* any_cast(any* __any) noexcept |
| 544 |
{ |
| 545 |
if constexpr (is_object_v<_ValueType>) |
| 546 |
if (__any) |
| 547 |
return static_cast<_ValueType*>(__any_caster<_ValueType>(__any)); |
| 548 |
return nullptr; |
| 549 |
} |
| 550 |
/// @} |
| 551 |
|
| 552 |
template<typename _Tp> |
| 553 |
void |
| 554 |
any::_Manager_internal<_Tp>:: |
| 555 |
_S_manage(_Op __which, const any* __any, _Arg* __arg) |
| 556 |
{ |
| 557 |
// The contained object is in _M_storage._M_buffer |
| 558 |
auto __ptr = reinterpret_cast<const _Tp*>(&__any->_M_storage._M_buffer); |
| 559 |
switch (__which) |
| 560 |
{ |
| 561 |
case _Op_access: |
| 562 |
__arg->_M_obj = const_cast<_Tp*>(__ptr); |
| 563 |
break; |
| 564 |
case _Op_get_type_info: |
| 565 |
#if __cpp_rtti |
| 566 |
__arg->_M_typeinfo = &typeid(_Tp); |
| 567 |
#endif |
| 568 |
break; |
| 569 |
case _Op_clone: |
| 570 |
::new(&__arg->_M_any->_M_storage._M_buffer) _Tp(*__ptr); |
| 571 |
__arg->_M_any->_M_manager = __any->_M_manager; |
| 572 |
break; |
| 573 |
case _Op_destroy: |
| 574 |
__ptr->~_Tp(); |
| 575 |
break; |
| 576 |
case _Op_xfer: |
| 577 |
::new(&__arg->_M_any->_M_storage._M_buffer) _Tp |
| 578 |
(std::move(*const_cast<_Tp*>(__ptr))); |
| 579 |
__ptr->~_Tp(); |
| 580 |
__arg->_M_any->_M_manager = __any->_M_manager; |
| 581 |
const_cast<any*>(__any)->_M_manager = nullptr; |
| 582 |
break; |
| 583 |
} |
| 584 |
} |
| 585 |
|
| 586 |
template<typename _Tp> |
| 587 |
void |
| 588 |
any::_Manager_external<_Tp>:: |
| 589 |
_S_manage(_Op __which, const any* __any, _Arg* __arg) |
| 590 |
{ |
| 591 |
// The contained object is *_M_storage._M_ptr |
| 592 |
auto __ptr = static_cast<const _Tp*>(__any->_M_storage._M_ptr); |
| 593 |
switch (__which) |
| 594 |
{ |
| 595 |
case _Op_access: |
| 596 |
__arg->_M_obj = const_cast<_Tp*>(__ptr); |
| 597 |
break; |
| 598 |
case _Op_get_type_info: |
| 599 |
#if __cpp_rtti |
| 600 |
__arg->_M_typeinfo = &typeid(_Tp); |
| 601 |
#endif |
| 602 |
break; |
| 603 |
case _Op_clone: |
| 604 |
__arg->_M_any->_M_storage._M_ptr = new _Tp(*__ptr); |
| 605 |
__arg->_M_any->_M_manager = __any->_M_manager; |
| 606 |
break; |
| 607 |
case _Op_destroy: |
| 608 |
delete __ptr; |
| 609 |
break; |
| 610 |
case _Op_xfer: |
| 611 |
__arg->_M_any->_M_storage._M_ptr = __any->_M_storage._M_ptr; |
| 612 |
__arg->_M_any->_M_manager = __any->_M_manager; |
| 613 |
const_cast<any*>(__any)->_M_manager = nullptr; |
| 614 |
break; |
| 615 |
} |
| 616 |
} |
| 617 |
|
| 618 |
/// @} |
| 619 |
|
| 620 |
namespace __detail::__variant |
| 621 |
{ |
| 622 |
template<typename> struct _Never_valueless_alt; // see <variant> |
| 623 |
|
| 624 |
// Provide the strong exception-safety guarantee when emplacing an |
| 625 |
// any into a variant. |
| 626 |
template<> |
| 627 |
struct _Never_valueless_alt<std::any> |
| 628 |
: std::true_type |
| 629 |
{ }; |
| 630 |
} // namespace __detail::__variant |
| 631 |
|
| 632 |
_GLIBCXX_END_NAMESPACE_VERSION |
| 633 |
} // namespace std |
| 634 |
|
| 635 |
#endif // C++17 |
| 636 |
#endif // _GLIBCXX_ANY |
