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_VARIANT 11#define _LIBCPP_VARIANT 12 13/* 14 variant synopsis 15 16namespace std { 17 18 // 20.7.2, class template variant 19 template <class... Types> 20 class variant { 21 public: 22 23 // 20.7.2.1, constructors 24 constexpr variant() noexcept(see below); 25 constexpr variant(const variant&); 26 constexpr variant(variant&&) noexcept(see below); 27 28 template <class T> constexpr variant(T&&) noexcept(see below); 29 30 template <class T, class... Args> 31 constexpr explicit variant(in_place_type_t<T>, Args&&...); 32 33 template <class T, class U, class... Args> 34 constexpr explicit variant( 35 in_place_type_t<T>, initializer_list<U>, Args&&...); 36 37 template <size_t I, class... Args> 38 constexpr explicit variant(in_place_index_t<I>, Args&&...); 39 40 template <size_t I, class U, class... Args> 41 constexpr explicit variant( 42 in_place_index_t<I>, initializer_list<U>, Args&&...); 43 44 // 20.7.2.2, destructor 45 constexpr ~variant(); // constexpr since c++20 46 47 // 20.7.2.3, assignment 48 constexpr variant& operator=(const variant&); 49 constexpr variant& operator=(variant&&) noexcept(see below); 50 51 template <class T> 52 constexpr variant& operator=(T&&) noexcept(see below); // constexpr since c++20 53 54 // 20.7.2.4, modifiers 55 template <class T, class... Args> 56 constexpr T& emplace(Args&&...); // constexpr since c++20 57 58 template <class T, class U, class... Args> 59 constexpr T& emplace(initializer_list<U>, Args&&...); // constexpr since c++20 60 61 template <size_t I, class... Args> 62 constexpr variant_alternative_t<I, variant>& emplace(Args&&...); // constexpr since c++20 63 64 template <size_t I, class U, class... Args> 65 constexpr variant_alternative_t<I, variant>& 66 emplace(initializer_list<U>, Args&&...); // constexpr since c++20 67 68 // 20.7.2.5, value status 69 constexpr bool valueless_by_exception() const noexcept; 70 constexpr size_t index() const noexcept; 71 72 // 20.7.2.6, swap 73 void swap(variant&) noexcept(see below); 74 75 // [variant.visit], visitation 76 template<class Self, class Visitor> 77 constexpr decltype(auto) visit(this Self&&, Visitor&&); // Since C++26 78 template<class R, class Self, class Visitor> 79 constexpr R visit(this Self&&, Visitor&&); // Since C++26 80 }; 81 82 // 20.7.3, variant helper classes 83 template <class T> struct variant_size; // undefined 84 85 template <class T> 86 inline constexpr size_t variant_size_v = variant_size<T>::value; 87 88 template <class T> struct variant_size<const T>; 89 template <class T> struct variant_size<volatile T>; 90 template <class T> struct variant_size<const volatile T>; 91 92 template <class... Types> 93 struct variant_size<variant<Types...>>; 94 95 template <size_t I, class T> struct variant_alternative; // undefined 96 97 template <size_t I, class T> 98 using variant_alternative_t = typename variant_alternative<I, T>::type; 99 100 template <size_t I, class T> struct variant_alternative<I, const T>; 101 template <size_t I, class T> struct variant_alternative<I, volatile T>; 102 template <size_t I, class T> struct variant_alternative<I, const volatile T>; 103 104 template <size_t I, class... Types> 105 struct variant_alternative<I, variant<Types...>>; 106 107 inline constexpr size_t variant_npos = -1; 108 109 // 20.7.4, value access 110 template <class T, class... Types> 111 constexpr bool holds_alternative(const variant<Types...>&) noexcept; 112 113 template <size_t I, class... Types> 114 constexpr variant_alternative_t<I, variant<Types...>>& 115 get(variant<Types...>&); 116 117 template <size_t I, class... Types> 118 constexpr variant_alternative_t<I, variant<Types...>>&& 119 get(variant<Types...>&&); 120 121 template <size_t I, class... Types> 122 constexpr variant_alternative_t<I, variant<Types...>> const& 123 get(const variant<Types...>&); 124 125 template <size_t I, class... Types> 126 constexpr variant_alternative_t<I, variant<Types...>> const&& 127 get(const variant<Types...>&&); 128 129 template <class T, class... Types> 130 constexpr T& get(variant<Types...>&); 131 132 template <class T, class... Types> 133 constexpr T&& get(variant<Types...>&&); 134 135 template <class T, class... Types> 136 constexpr const T& get(const variant<Types...>&); 137 138 template <class T, class... Types> 139 constexpr const T&& get(const variant<Types...>&&); 140 141 template <size_t I, class... Types> 142 constexpr add_pointer_t<variant_alternative_t<I, variant<Types...>>> 143 get_if(variant<Types...>*) noexcept; 144 145 template <size_t I, class... Types> 146 constexpr add_pointer_t<const variant_alternative_t<I, variant<Types...>>> 147 get_if(const variant<Types...>*) noexcept; 148 149 template <class T, class... Types> 150 constexpr add_pointer_t<T> 151 get_if(variant<Types...>*) noexcept; 152 153 template <class T, class... Types> 154 constexpr add_pointer_t<const T> 155 get_if(const variant<Types...>*) noexcept; 156 157 // 20.7.5, relational operators 158 template <class... Types> 159 constexpr bool operator==(const variant<Types...>&, const variant<Types...>&); 160 161 template <class... Types> 162 constexpr bool operator!=(const variant<Types...>&, const variant<Types...>&); 163 164 template <class... Types> 165 constexpr bool operator<(const variant<Types...>&, const variant<Types...>&); 166 167 template <class... Types> 168 constexpr bool operator>(const variant<Types...>&, const variant<Types...>&); 169 170 template <class... Types> 171 constexpr bool operator<=(const variant<Types...>&, const variant<Types...>&); 172 173 template <class... Types> 174 constexpr bool operator>=(const variant<Types...>&, const variant<Types...>&); 175 176 template <class... Types> requires (three_way_comparable<Types> && ...) 177 constexpr common_comparison_category_t<compare_three_way_result_t<Types>...> 178 operator<=>(const variant<Types...>&, const variant<Types...>&); // since C++20 179 180 // 20.7.6, visitation 181 template <class Visitor, class... Variants> 182 constexpr see below visit(Visitor&&, Variants&&...); 183 184 template <class R, class Visitor, class... Variants> 185 constexpr R visit(Visitor&&, Variants&&...); // since C++20 186 187 // 20.7.7, class monostate 188 struct monostate; 189 190 // 20.7.8, monostate relational operators 191 constexpr bool operator==(monostate, monostate) noexcept; 192 constexpr bool operator!=(monostate, monostate) noexcept; // until C++20 193 constexpr bool operator<(monostate, monostate) noexcept; // until C++20 194 constexpr bool operator>(monostate, monostate) noexcept; // until C++20 195 constexpr bool operator<=(monostate, monostate) noexcept; // until C++20 196 constexpr bool operator>=(monostate, monostate) noexcept; // until C++20 197 constexpr strong_ordering operator<=>(monostate, monostate) noexcept; // since C++20 198 199 // 20.7.9, specialized algorithms 200 template <class... Types> 201 void swap(variant<Types...>&, variant<Types...>&) noexcept(see below); 202 203 // 20.7.10, class bad_variant_access 204 class bad_variant_access; 205 206 // 20.7.11, hash support 207 template <class T> struct hash; 208 template <class... Types> struct hash<variant<Types...>>; 209 template <> struct hash<monostate>; 210 211} // namespace std 212 213*/ 214 215#include <__compare/common_comparison_category.h> 216#include <__compare/compare_three_way_result.h> 217#include <__compare/three_way_comparable.h> 218#include <__config> 219#include <__exception/exception.h> 220#include <__functional/hash.h> 221#include <__functional/invoke.h> 222#include <__functional/operations.h> 223#include <__functional/unary_function.h> 224#include <__memory/addressof.h> 225#include <__memory/construct_at.h> 226#include <__tuple/find_index.h> 227#include <__tuple/sfinae_helpers.h> 228#include <__type_traits/add_const.h> 229#include <__type_traits/add_cv.h> 230#include <__type_traits/add_pointer.h> 231#include <__type_traits/add_volatile.h> 232#include <__type_traits/common_type.h> 233#include <__type_traits/conjunction.h> 234#include <__type_traits/dependent_type.h> 235#include <__type_traits/is_array.h> 236#include <__type_traits/is_constructible.h> 237#include <__type_traits/is_destructible.h> 238#include <__type_traits/is_nothrow_assignable.h> 239#include <__type_traits/is_nothrow_constructible.h> 240#include <__type_traits/is_reference.h> 241#include <__type_traits/is_trivially_assignable.h> 242#include <__type_traits/is_trivially_constructible.h> 243#include <__type_traits/is_trivially_destructible.h> 244#include <__type_traits/is_trivially_relocatable.h> 245#include <__type_traits/is_void.h> 246#include <__type_traits/remove_const.h> 247#include <__type_traits/remove_cvref.h> 248#include <__type_traits/type_identity.h> 249#include <__type_traits/void_t.h> 250#include <__utility/declval.h> 251#include <__utility/forward.h> 252#include <__utility/forward_like.h> 253#include <__utility/in_place.h> 254#include <__utility/integer_sequence.h> 255#include <__utility/move.h> 256#include <__utility/swap.h> 257#include <__variant/monostate.h> 258#include <__verbose_abort> 259#include <initializer_list> 260#include <limits> 261#include <new> 262#include <version> 263 264// standard-mandated includes 265 266// [variant.syn] 267#include <compare> 268 269#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 270# pragma GCC system_header 271#endif 272 273_LIBCPP_PUSH_MACROS 274#include <__undef_macros> 275 276namespace std { // explicitly not using versioning namespace 277 278class _LIBCPP_EXPORTED_FROM_ABI _LIBCPP_AVAILABILITY_BAD_VARIANT_ACCESS bad_variant_access : public exception { 279public: 280 const char* what() const _NOEXCEPT override; 281}; 282 283} // namespace std 284 285_LIBCPP_BEGIN_NAMESPACE_STD 286 287#if _LIBCPP_STD_VER >= 17 288 289// Light N-dimensional array of function pointers. Used in place of std::array to avoid 290// adding a dependency. 291template <class _Tp, size_t _Size> 292struct __farray { 293 static_assert(_Size > 0, "N-dimensional array should never be empty in std::visit"); 294 _Tp __buf_[_Size] = {}; 295 296 _LIBCPP_HIDE_FROM_ABI constexpr const _Tp& operator[](size_t __n) const noexcept { return __buf_[__n]; } 297}; 298 299_LIBCPP_NORETURN inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS void 300__throw_bad_variant_access() { 301# ifndef _LIBCPP_HAS_NO_EXCEPTIONS 302 throw bad_variant_access(); 303# else 304 _LIBCPP_VERBOSE_ABORT("bad_variant_access was thrown in -fno-exceptions mode"); 305# endif 306} 307 308template <class... _Types> 309class _LIBCPP_TEMPLATE_VIS variant; 310 311template <class _Tp> 312struct _LIBCPP_TEMPLATE_VIS variant_size; 313 314template <class _Tp> 315inline constexpr size_t variant_size_v = variant_size<_Tp>::value; 316 317template <class _Tp> 318struct _LIBCPP_TEMPLATE_VIS variant_size<const _Tp> : variant_size<_Tp> {}; 319 320template <class _Tp> 321struct _LIBCPP_TEMPLATE_VIS variant_size<volatile _Tp> : variant_size<_Tp> {}; 322 323template <class _Tp> 324struct _LIBCPP_TEMPLATE_VIS variant_size<const volatile _Tp> : variant_size<_Tp> {}; 325 326template <class... _Types> 327struct _LIBCPP_TEMPLATE_VIS variant_size<variant<_Types...>> : integral_constant<size_t, sizeof...(_Types)> {}; 328 329template <size_t _Ip, class _Tp> 330struct _LIBCPP_TEMPLATE_VIS variant_alternative; 331 332template <size_t _Ip, class _Tp> 333using variant_alternative_t = typename variant_alternative<_Ip, _Tp>::type; 334 335template <size_t _Ip, class _Tp> 336struct _LIBCPP_TEMPLATE_VIS variant_alternative<_Ip, const _Tp> : add_const<variant_alternative_t<_Ip, _Tp>> {}; 337 338template <size_t _Ip, class _Tp> 339struct _LIBCPP_TEMPLATE_VIS variant_alternative<_Ip, volatile _Tp> : add_volatile<variant_alternative_t<_Ip, _Tp>> {}; 340 341template <size_t _Ip, class _Tp> 342struct _LIBCPP_TEMPLATE_VIS variant_alternative<_Ip, const volatile _Tp> : add_cv<variant_alternative_t<_Ip, _Tp>> {}; 343 344template <size_t _Ip, class... _Types> 345struct _LIBCPP_TEMPLATE_VIS variant_alternative<_Ip, variant<_Types...>> { 346 static_assert(_Ip < sizeof...(_Types), "Index out of bounds in std::variant_alternative<>"); 347 using type = __type_pack_element<_Ip, _Types...>; 348}; 349 350inline constexpr size_t variant_npos = static_cast<size_t>(-1); 351 352template <size_t _NumAlternatives> 353_LIBCPP_HIDE_FROM_ABI constexpr auto __choose_index_type() { 354# ifdef _LIBCPP_ABI_VARIANT_INDEX_TYPE_OPTIMIZATION 355 if constexpr (_NumAlternatives < numeric_limits<unsigned char>::max()) 356 return static_cast<unsigned char>(0); 357 else if constexpr (_NumAlternatives < numeric_limits<unsigned short>::max()) 358 return static_cast<unsigned short>(0); 359 else 360# endif // _LIBCPP_ABI_VARIANT_INDEX_TYPE_OPTIMIZATION 361 return static_cast<unsigned int>(0); 362} 363 364template <size_t _NumAlts> 365using __variant_index_t = decltype(std::__choose_index_type<_NumAlts>()); 366 367template <class _IndexType> 368constexpr _IndexType __variant_npos = static_cast<_IndexType>(-1); 369 370template <class... _Types> 371class _LIBCPP_TEMPLATE_VIS variant; 372 373template <class... _Types> 374_LIBCPP_HIDE_FROM_ABI constexpr variant<_Types...>& __as_variant(variant<_Types...>& __vs) noexcept { 375 return __vs; 376} 377 378template <class... _Types> 379_LIBCPP_HIDE_FROM_ABI constexpr const variant<_Types...>& __as_variant(const variant<_Types...>& __vs) noexcept { 380 return __vs; 381} 382 383template <class... _Types> 384_LIBCPP_HIDE_FROM_ABI constexpr variant<_Types...>&& __as_variant(variant<_Types...>&& __vs) noexcept { 385 return std::move(__vs); 386} 387 388template <class... _Types> 389_LIBCPP_HIDE_FROM_ABI constexpr const variant<_Types...>&& __as_variant(const variant<_Types...>&& __vs) noexcept { 390 return std::move(__vs); 391} 392 393namespace __find_detail { 394 395template <class _Tp, class... _Types> 396_LIBCPP_HIDE_FROM_ABI constexpr size_t __find_index() { 397 constexpr bool __matches[] = {is_same_v<_Tp, _Types>...}; 398 size_t __result = __not_found; 399 for (size_t __i = 0; __i < sizeof...(_Types); ++__i) { 400 if (__matches[__i]) { 401 if (__result != __not_found) { 402 return __ambiguous; 403 } 404 __result = __i; 405 } 406 } 407 return __result; 408} 409 410template <size_t _Index> 411struct __find_unambiguous_index_sfinae_impl : integral_constant<size_t, _Index> {}; 412 413template <> 414struct __find_unambiguous_index_sfinae_impl<__not_found> {}; 415 416template <> 417struct __find_unambiguous_index_sfinae_impl<__ambiguous> {}; 418 419template <class _Tp, class... _Types> 420struct __find_unambiguous_index_sfinae : __find_unambiguous_index_sfinae_impl<__find_index<_Tp, _Types...>()> {}; 421 422} // namespace __find_detail 423 424namespace __variant_detail { 425 426struct __valueless_t {}; 427 428enum class _Trait { _TriviallyAvailable, _Available, _Unavailable }; 429 430template <typename _Tp, template <typename> class _IsTriviallyAvailable, template <typename> class _IsAvailable> 431constexpr _Trait __trait = 432 _IsTriviallyAvailable<_Tp>::value ? _Trait::_TriviallyAvailable 433 : _IsAvailable<_Tp>::value 434 ? _Trait::_Available 435 : _Trait::_Unavailable; 436 437_LIBCPP_HIDE_FROM_ABI constexpr _Trait __common_trait(initializer_list<_Trait> __traits) { 438 _Trait __result = _Trait::_TriviallyAvailable; 439 for (_Trait __t : __traits) { 440 if (static_cast<int>(__t) > static_cast<int>(__result)) { 441 __result = __t; 442 } 443 } 444 return __result; 445} 446 447template <typename... _Types> 448struct __traits { 449 static constexpr _Trait __copy_constructible_trait = 450 __variant_detail::__common_trait({__trait<_Types, is_trivially_copy_constructible, is_copy_constructible>...}); 451 452 static constexpr _Trait __move_constructible_trait = 453 __variant_detail::__common_trait({__trait<_Types, is_trivially_move_constructible, is_move_constructible>...}); 454 455 static constexpr _Trait __copy_assignable_trait = __variant_detail::__common_trait( 456 {__copy_constructible_trait, __trait<_Types, is_trivially_copy_assignable, is_copy_assignable>...}); 457 458 static constexpr _Trait __move_assignable_trait = __variant_detail::__common_trait( 459 {__move_constructible_trait, __trait<_Types, is_trivially_move_assignable, is_move_assignable>...}); 460 461 static constexpr _Trait __destructible_trait = 462 __variant_detail::__common_trait({__trait<_Types, is_trivially_destructible, is_destructible>...}); 463}; 464 465namespace __access { 466 467struct __union { 468 template <class _Vp> 469 _LIBCPP_HIDE_FROM_ABI static constexpr auto&& __get_alt(_Vp&& __v, in_place_index_t<0>) { 470 return std::forward<_Vp>(__v).__head; 471 } 472 473 template <class _Vp, size_t _Ip> 474 _LIBCPP_HIDE_FROM_ABI static constexpr auto&& __get_alt(_Vp&& __v, in_place_index_t<_Ip>) { 475 return __get_alt(std::forward<_Vp>(__v).__tail, in_place_index<_Ip - 1>); 476 } 477}; 478 479struct __base { 480 template <size_t _Ip, class _Vp> 481 _LIBCPP_HIDE_FROM_ABI static constexpr auto&& __get_alt(_Vp&& __v) { 482 return __union::__get_alt(std::forward<_Vp>(__v).__data, in_place_index<_Ip>); 483 } 484}; 485 486struct __variant { 487 template <size_t _Ip, class _Vp> 488 _LIBCPP_HIDE_FROM_ABI static constexpr auto&& __get_alt(_Vp&& __v) { 489 return __base::__get_alt<_Ip>(std::forward<_Vp>(__v).__impl_); 490 } 491}; 492 493} // namespace __access 494 495namespace __visitation { 496 497struct __base { 498 template <class _Visitor, class... _Vs> 499 _LIBCPP_HIDE_FROM_ABI static constexpr decltype(auto) 500 __visit_alt_at(size_t __index, _Visitor&& __visitor, _Vs&&... __vs) { 501 constexpr auto __fdiagonal = __make_fdiagonal<_Visitor&&, decltype(std::forward<_Vs>(__vs).__as_base())...>(); 502 return __fdiagonal[__index](std::forward<_Visitor>(__visitor), std::forward<_Vs>(__vs).__as_base()...); 503 } 504 505 template <class _Visitor, class... _Vs> 506 _LIBCPP_HIDE_FROM_ABI static constexpr decltype(auto) __visit_alt(_Visitor&& __visitor, _Vs&&... __vs) { 507 constexpr auto __fmatrix = __make_fmatrix<_Visitor&&, decltype(std::forward<_Vs>(__vs).__as_base())...>(); 508 return __at(__fmatrix, __vs.index()...)(std::forward<_Visitor>(__visitor), std::forward<_Vs>(__vs).__as_base()...); 509 } 510 511private: 512 template <class _Tp> 513 _LIBCPP_HIDE_FROM_ABI static constexpr const _Tp& __at(const _Tp& __elem) { 514 return __elem; 515 } 516 517 template <class _Tp, size_t _Np, typename... _Indices> 518 _LIBCPP_HIDE_FROM_ABI static constexpr auto&& 519 __at(const __farray<_Tp, _Np>& __elems, size_t __index, _Indices... __indices) { 520 return __at(__elems[__index], __indices...); 521 } 522 523 template <class _Fp, class... _Fs> 524 static _LIBCPP_HIDE_FROM_ABI constexpr void __std_visit_visitor_return_type_check() { 525 static_assert( 526 __all<is_same_v<_Fp, _Fs>...>::value, "`std::visit` requires the visitor to have a single return type."); 527 } 528 529 template <class... _Fs> 530 _LIBCPP_HIDE_FROM_ABI static constexpr auto __make_farray(_Fs&&... __fs) { 531 __std_visit_visitor_return_type_check<__remove_cvref_t<_Fs>...>(); 532 using __result = __farray<common_type_t<__remove_cvref_t<_Fs>...>, sizeof...(_Fs)>; 533 return __result{{std::forward<_Fs>(__fs)...}}; 534 } 535 536 template <size_t... _Is> 537 struct __dispatcher { 538 template <class _Fp, class... _Vs> 539 _LIBCPP_HIDE_FROM_ABI static constexpr decltype(auto) __dispatch(_Fp __f, _Vs... __vs) { 540 return std::__invoke(static_cast<_Fp>(__f), __access::__base::__get_alt<_Is>(static_cast<_Vs>(__vs))...); 541 } 542 }; 543 544 template <class _Fp, class... _Vs, size_t... _Is> 545 _LIBCPP_HIDE_FROM_ABI static constexpr auto __make_dispatch(index_sequence<_Is...>) { 546 return __dispatcher<_Is...>::template __dispatch<_Fp, _Vs...>; 547 } 548 549 template <size_t _Ip, class _Fp, class... _Vs> 550 _LIBCPP_HIDE_FROM_ABI static constexpr auto __make_fdiagonal_impl() { 551 return __make_dispatch<_Fp, _Vs...>(index_sequence<((void)__type_identity<_Vs>{}, _Ip)...>{}); 552 } 553 554 template <class _Fp, class... _Vs, size_t... _Is> 555 _LIBCPP_HIDE_FROM_ABI static constexpr auto __make_fdiagonal_impl(index_sequence<_Is...>) { 556 return __base::__make_farray(__make_fdiagonal_impl<_Is, _Fp, _Vs...>()...); 557 } 558 559 template <class _Fp, class _Vp, class... _Vs> 560 _LIBCPP_HIDE_FROM_ABI static constexpr auto __make_fdiagonal() { 561 constexpr size_t __np = __remove_cvref_t<_Vp>::__size(); 562 static_assert(__all<(__np == __remove_cvref_t<_Vs>::__size())...>::value); 563 return __make_fdiagonal_impl<_Fp, _Vp, _Vs...>(make_index_sequence<__np>{}); 564 } 565 566 template <class _Fp, class... _Vs, size_t... _Is> 567 _LIBCPP_HIDE_FROM_ABI static constexpr auto __make_fmatrix_impl(index_sequence<_Is...> __is) { 568 return __make_dispatch<_Fp, _Vs...>(__is); 569 } 570 571 template <class _Fp, class... _Vs, size_t... _Is, size_t... _Js, class... _Ls> 572 _LIBCPP_HIDE_FROM_ABI static constexpr auto 573 __make_fmatrix_impl(index_sequence<_Is...>, index_sequence<_Js...>, _Ls... __ls) { 574 return __base::__make_farray(__make_fmatrix_impl<_Fp, _Vs...>(index_sequence<_Is..., _Js>{}, __ls...)...); 575 } 576 577 template <class _Fp, class... _Vs> 578 _LIBCPP_HIDE_FROM_ABI static constexpr auto __make_fmatrix() { 579 return __make_fmatrix_impl<_Fp, _Vs...>( 580 index_sequence<>{}, make_index_sequence<__remove_cvref_t<_Vs>::__size()>{}...); 581 } 582}; 583 584struct __variant { 585 template <class _Visitor, class... _Vs> 586 _LIBCPP_HIDE_FROM_ABI static constexpr decltype(auto) 587 __visit_alt_at(size_t __index, _Visitor&& __visitor, _Vs&&... __vs) { 588 return __base::__visit_alt_at(__index, std::forward<_Visitor>(__visitor), std::forward<_Vs>(__vs).__impl_...); 589 } 590 591 template <class _Visitor, class... _Vs> 592 _LIBCPP_HIDE_FROM_ABI static constexpr decltype(auto) __visit_alt(_Visitor&& __visitor, _Vs&&... __vs) { 593 return __base::__visit_alt( 594 std::forward<_Visitor>(__visitor), std::__as_variant(std::forward<_Vs>(__vs)).__impl_...); 595 } 596 597 template <class _Visitor, class... _Vs> 598 _LIBCPP_HIDE_FROM_ABI static constexpr decltype(auto) 599 __visit_value_at(size_t __index, _Visitor&& __visitor, _Vs&&... __vs) { 600 return __visit_alt_at(__index, __make_value_visitor(std::forward<_Visitor>(__visitor)), std::forward<_Vs>(__vs)...); 601 } 602 603 template <class _Visitor, class... _Vs> 604 _LIBCPP_HIDE_FROM_ABI static constexpr decltype(auto) __visit_value(_Visitor&& __visitor, _Vs&&... __vs) { 605 return __visit_alt(__make_value_visitor(std::forward<_Visitor>(__visitor)), std::forward<_Vs>(__vs)...); 606 } 607 608# if _LIBCPP_STD_VER >= 20 609 template <class _Rp, class _Visitor, class... _Vs> 610 _LIBCPP_HIDE_FROM_ABI static constexpr _Rp __visit_value(_Visitor&& __visitor, _Vs&&... __vs) { 611 return __visit_alt(__make_value_visitor<_Rp>(std::forward<_Visitor>(__visitor)), std::forward<_Vs>(__vs)...); 612 } 613# endif 614 615private: 616 template <class _Visitor, class... _Values> 617 static _LIBCPP_HIDE_FROM_ABI constexpr void __std_visit_exhaustive_visitor_check() { 618 static_assert(is_invocable_v<_Visitor, _Values...>, "`std::visit` requires the visitor to be exhaustive."); 619 } 620 621 template <class _Visitor> 622 struct __value_visitor { 623 template <class... _Alts> 624 _LIBCPP_HIDE_FROM_ABI constexpr decltype(auto) operator()(_Alts&&... __alts) const { 625 __std_visit_exhaustive_visitor_check< _Visitor, decltype((std::forward<_Alts>(__alts).__value))...>(); 626 return std::__invoke(std::forward<_Visitor>(__visitor), std::forward<_Alts>(__alts).__value...); 627 } 628 _Visitor&& __visitor; 629 }; 630 631# if _LIBCPP_STD_VER >= 20 632 template <class _Rp, class _Visitor> 633 struct __value_visitor_return_type { 634 template <class... _Alts> 635 _LIBCPP_HIDE_FROM_ABI constexpr _Rp operator()(_Alts&&... __alts) const { 636 __std_visit_exhaustive_visitor_check< _Visitor, decltype((std::forward<_Alts>(__alts).__value))...>(); 637 if constexpr (is_void_v<_Rp>) { 638 std::__invoke(std::forward<_Visitor>(__visitor), std::forward<_Alts>(__alts).__value...); 639 } else { 640 return std::__invoke(std::forward<_Visitor>(__visitor), std::forward<_Alts>(__alts).__value...); 641 } 642 } 643 644 _Visitor&& __visitor; 645 }; 646# endif 647 648 template <class _Visitor> 649 _LIBCPP_HIDE_FROM_ABI static constexpr auto __make_value_visitor(_Visitor&& __visitor) { 650 return __value_visitor<_Visitor>{std::forward<_Visitor>(__visitor)}; 651 } 652 653# if _LIBCPP_STD_VER >= 20 654 template <class _Rp, class _Visitor> 655 _LIBCPP_HIDE_FROM_ABI static constexpr auto __make_value_visitor(_Visitor&& __visitor) { 656 return __value_visitor_return_type<_Rp, _Visitor>{std::forward<_Visitor>(__visitor)}; 657 } 658# endif 659}; 660 661} // namespace __visitation 662 663// Adding semi-colons in macro expansions helps clang-format to do a better job. 664// This macro is used to avoid compilation errors due to "stray" semi-colons. 665# define _LIBCPP_EAT_SEMICOLON static_assert(true, "") 666 667template <size_t _Index, class _Tp> 668struct _LIBCPP_TEMPLATE_VIS __alt { 669 using __value_type = _Tp; 670 static constexpr size_t __index = _Index; 671 672 template <class... _Args> 673 _LIBCPP_HIDE_FROM_ABI explicit constexpr __alt(in_place_t, _Args&&... __args) 674 : __value(std::forward<_Args>(__args)...) {} 675 676 __value_type __value; 677}; 678 679template <_Trait _DestructibleTrait, size_t _Index, class... _Types> 680union _LIBCPP_TEMPLATE_VIS __union; 681 682template <_Trait _DestructibleTrait, size_t _Index> 683union _LIBCPP_TEMPLATE_VIS __union<_DestructibleTrait, _Index> {}; 684 685# define _LIBCPP_VARIANT_UNION(destructible_trait, destructor_definition) \ 686 template <size_t _Index, class _Tp, class... _Types> \ 687 union _LIBCPP_TEMPLATE_VIS __union<destructible_trait, _Index, _Tp, _Types...> { \ 688 public: \ 689 _LIBCPP_HIDE_FROM_ABI explicit constexpr __union(__valueless_t) noexcept : __dummy{} {} \ 690 \ 691 template <class... _Args> \ 692 _LIBCPP_HIDE_FROM_ABI explicit constexpr __union(in_place_index_t<0>, _Args&&... __args) \ 693 : __head(in_place, std::forward<_Args>(__args)...) {} \ 694 \ 695 template <size_t _Ip, class... _Args> \ 696 _LIBCPP_HIDE_FROM_ABI explicit constexpr __union(in_place_index_t<_Ip>, _Args&&... __args) \ 697 : __tail(in_place_index<_Ip - 1>, std::forward<_Args>(__args)...) {} \ 698 \ 699 _LIBCPP_HIDE_FROM_ABI __union(const __union&) = default; \ 700 _LIBCPP_HIDE_FROM_ABI __union(__union&&) = default; \ 701 _LIBCPP_HIDE_FROM_ABI __union& operator=(const __union&) = default; \ 702 _LIBCPP_HIDE_FROM_ABI __union& operator=(__union&&) = default; \ 703 destructor_definition; \ 704 \ 705 private: \ 706 char __dummy; \ 707 __alt<_Index, _Tp> __head; \ 708 __union<destructible_trait, _Index + 1, _Types...> __tail; \ 709 \ 710 friend struct __access::__union; \ 711 } 712 713_LIBCPP_VARIANT_UNION(_Trait::_TriviallyAvailable, 714 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 ~__union() = default); 715_LIBCPP_VARIANT_UNION( 716 _Trait::_Available, _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 ~__union() {} _LIBCPP_EAT_SEMICOLON); 717_LIBCPP_VARIANT_UNION(_Trait::_Unavailable, _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 ~__union() = delete); 718 719# undef _LIBCPP_VARIANT_UNION 720 721template <_Trait _DestructibleTrait, class... _Types> 722class _LIBCPP_TEMPLATE_VIS __base { 723public: 724 using __index_t = __variant_index_t<sizeof...(_Types)>; 725 726 _LIBCPP_HIDE_FROM_ABI explicit constexpr __base(__valueless_t __tag) noexcept 727 : __data(__tag), __index(__variant_npos<__index_t>) {} 728 729 template <size_t _Ip, class... _Args> 730 _LIBCPP_HIDE_FROM_ABI explicit constexpr __base(in_place_index_t<_Ip>, _Args&&... __args) 731 : __data(in_place_index<_Ip>, std::forward<_Args>(__args)...), __index(_Ip) {} 732 733 _LIBCPP_HIDE_FROM_ABI constexpr bool valueless_by_exception() const noexcept { return index() == variant_npos; } 734 735 _LIBCPP_HIDE_FROM_ABI constexpr size_t index() const noexcept { 736 return __index == __variant_npos<__index_t> ? variant_npos : __index; 737 } 738 739protected: 740 _LIBCPP_HIDE_FROM_ABI constexpr auto&& __as_base() & { return *this; } 741 742 _LIBCPP_HIDE_FROM_ABI constexpr auto&& __as_base() && { return std::move(*this); } 743 744 _LIBCPP_HIDE_FROM_ABI constexpr auto&& __as_base() const& { return *this; } 745 746 _LIBCPP_HIDE_FROM_ABI constexpr auto&& __as_base() const&& { return std::move(*this); } 747 748 _LIBCPP_HIDE_FROM_ABI static constexpr size_t __size() { return sizeof...(_Types); } 749 750 __union<_DestructibleTrait, 0, _Types...> __data; 751 __index_t __index; 752 753 friend struct __access::__base; 754 friend struct __visitation::__base; 755}; 756 757template <class _Traits, _Trait = _Traits::__destructible_trait> 758class _LIBCPP_TEMPLATE_VIS __dtor; 759 760# define _LIBCPP_VARIANT_DESTRUCTOR(destructible_trait, destructor_definition, destroy) \ 761 template <class... _Types> \ 762 class _LIBCPP_TEMPLATE_VIS __dtor<__traits<_Types...>, destructible_trait> \ 763 : public __base<destructible_trait, _Types...> { \ 764 using __base_type = __base<destructible_trait, _Types...>; \ 765 using __index_t = typename __base_type::__index_t; \ 766 \ 767 public: \ 768 using __base_type::__base_type; \ 769 using __base_type::operator=; \ 770 _LIBCPP_HIDE_FROM_ABI __dtor(const __dtor&) = default; \ 771 _LIBCPP_HIDE_FROM_ABI __dtor(__dtor&&) = default; \ 772 _LIBCPP_HIDE_FROM_ABI __dtor& operator=(const __dtor&) = default; \ 773 _LIBCPP_HIDE_FROM_ABI __dtor& operator=(__dtor&&) = default; \ 774 destructor_definition; \ 775 \ 776 protected: \ 777 destroy; \ 778 } 779 780_LIBCPP_VARIANT_DESTRUCTOR( 781 _Trait::_TriviallyAvailable, 782 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 ~__dtor() = default, 783 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __destroy() noexcept { 784 this->__index = __variant_npos<__index_t>; 785 } _LIBCPP_EAT_SEMICOLON); 786 787_LIBCPP_VARIANT_DESTRUCTOR( 788 _Trait::_Available, 789 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 ~__dtor() { __destroy(); } _LIBCPP_EAT_SEMICOLON, 790 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __destroy() noexcept { 791 if (!this->valueless_by_exception()) { 792 __visitation::__base::__visit_alt( 793 [](auto& __alt) noexcept { 794 using __alt_type = __remove_cvref_t<decltype(__alt)>; 795 __alt.~__alt_type(); 796 }, 797 *this); 798 } 799 this->__index = __variant_npos<__index_t>; 800 } _LIBCPP_EAT_SEMICOLON); 801 802_LIBCPP_VARIANT_DESTRUCTOR(_Trait::_Unavailable, 803 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 ~__dtor() = delete, 804 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __destroy() noexcept = delete); 805 806# undef _LIBCPP_VARIANT_DESTRUCTOR 807 808template <class _Traits> 809class _LIBCPP_TEMPLATE_VIS __ctor : public __dtor<_Traits> { 810 using __base_type = __dtor<_Traits>; 811 812public: 813 using __base_type::__base_type; 814 using __base_type::operator=; 815 816protected: 817 template <class _Rhs> 818 _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR_SINCE_CXX20 void __generic_construct(__ctor& __lhs, _Rhs&& __rhs) { 819 __lhs.__destroy(); 820 if (!__rhs.valueless_by_exception()) { 821 auto __rhs_index = __rhs.index(); 822 __visitation::__base::__visit_alt_at( 823 __rhs_index, 824 [&__lhs](auto&& __rhs_alt) { 825 std::__construct_at(std::addressof(__lhs.__data), 826 in_place_index<__decay_t<decltype(__rhs_alt)>::__index>, 827 std::forward<decltype(__rhs_alt)>(__rhs_alt).__value); 828 }, 829 std::forward<_Rhs>(__rhs)); 830 __lhs.__index = __rhs_index; 831 } 832 } 833}; 834 835template <class _Traits, _Trait = _Traits::__move_constructible_trait> 836class _LIBCPP_TEMPLATE_VIS __move_constructor; 837 838# define _LIBCPP_VARIANT_MOVE_CONSTRUCTOR(move_constructible_trait, move_constructor_definition) \ 839 template <class... _Types> \ 840 class _LIBCPP_TEMPLATE_VIS __move_constructor<__traits<_Types...>, move_constructible_trait> \ 841 : public __ctor<__traits<_Types...>> { \ 842 using __base_type = __ctor<__traits<_Types...>>; \ 843 \ 844 public: \ 845 using __base_type::__base_type; \ 846 using __base_type::operator=; \ 847 \ 848 _LIBCPP_HIDE_FROM_ABI __move_constructor(const __move_constructor&) = default; \ 849 _LIBCPP_HIDE_FROM_ABI ~__move_constructor() = default; \ 850 _LIBCPP_HIDE_FROM_ABI __move_constructor& operator=(const __move_constructor&) = default; \ 851 _LIBCPP_HIDE_FROM_ABI __move_constructor& operator=(__move_constructor&&) = default; \ 852 move_constructor_definition; \ 853 } 854 855_LIBCPP_VARIANT_MOVE_CONSTRUCTOR( 856 _Trait::_TriviallyAvailable, 857 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __move_constructor(__move_constructor&& __that) = default); 858 859_LIBCPP_VARIANT_MOVE_CONSTRUCTOR( 860 _Trait::_Available, 861 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __move_constructor(__move_constructor&& __that) noexcept( 862 __all<is_nothrow_move_constructible_v<_Types>...>::value) 863 : __move_constructor(__valueless_t{}) { 864 this->__generic_construct(*this, std::move(__that)); 865 } _LIBCPP_EAT_SEMICOLON); 866 867_LIBCPP_VARIANT_MOVE_CONSTRUCTOR( 868 _Trait::_Unavailable, 869 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __move_constructor(__move_constructor&&) = delete); 870 871# undef _LIBCPP_VARIANT_MOVE_CONSTRUCTOR 872 873template <class _Traits, _Trait = _Traits::__copy_constructible_trait> 874class _LIBCPP_TEMPLATE_VIS __copy_constructor; 875 876# define _LIBCPP_VARIANT_COPY_CONSTRUCTOR(copy_constructible_trait, copy_constructor_definition) \ 877 template <class... _Types> \ 878 class _LIBCPP_TEMPLATE_VIS __copy_constructor<__traits<_Types...>, copy_constructible_trait> \ 879 : public __move_constructor<__traits<_Types...>> { \ 880 using __base_type = __move_constructor<__traits<_Types...>>; \ 881 \ 882 public: \ 883 using __base_type::__base_type; \ 884 using __base_type::operator=; \ 885 \ 886 _LIBCPP_HIDE_FROM_ABI __copy_constructor(__copy_constructor&&) = default; \ 887 _LIBCPP_HIDE_FROM_ABI ~__copy_constructor() = default; \ 888 _LIBCPP_HIDE_FROM_ABI __copy_constructor& operator=(const __copy_constructor&) = default; \ 889 _LIBCPP_HIDE_FROM_ABI __copy_constructor& operator=(__copy_constructor&&) = default; \ 890 copy_constructor_definition; \ 891 } 892 893_LIBCPP_VARIANT_COPY_CONSTRUCTOR( 894 _Trait::_TriviallyAvailable, 895 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __copy_constructor(const __copy_constructor& __that) = default); 896 897_LIBCPP_VARIANT_COPY_CONSTRUCTOR( 898 _Trait::_Available, 899 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __copy_constructor(const __copy_constructor& __that) 900 : __copy_constructor(__valueless_t{}) { this->__generic_construct(*this, __that); } _LIBCPP_EAT_SEMICOLON); 901 902_LIBCPP_VARIANT_COPY_CONSTRUCTOR( 903 _Trait::_Unavailable, 904 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __copy_constructor(const __copy_constructor&) = delete); 905 906# undef _LIBCPP_VARIANT_COPY_CONSTRUCTOR 907 908template <class _Traits> 909class _LIBCPP_TEMPLATE_VIS __assignment : public __copy_constructor<_Traits> { 910 using __base_type = __copy_constructor<_Traits>; 911 912public: 913 using __base_type::__base_type; 914 using __base_type::operator=; 915 916 template <size_t _Ip, class... _Args> 917 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 auto& __emplace(_Args&&... __args) { 918 this->__destroy(); 919 std::__construct_at(std::addressof(this->__data), in_place_index<_Ip>, std::forward<_Args>(__args)...); 920 this->__index = _Ip; 921 return __access::__base::__get_alt<_Ip>(*this).__value; 922 } 923 924protected: 925 template <size_t _Ip, class _Tp, class _Arg> 926 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __assign_alt(__alt<_Ip, _Tp>& __a, _Arg&& __arg) { 927 if (this->index() == _Ip) { 928 __a.__value = std::forward<_Arg>(__arg); 929 } else { 930 struct { 931 _LIBCPP_HIDDEN _LIBCPP_CONSTEXPR_SINCE_CXX20 void operator()(true_type) const { 932 __this->__emplace<_Ip>(std::forward<_Arg>(__arg)); 933 } 934 _LIBCPP_HIDDEN _LIBCPP_CONSTEXPR_SINCE_CXX20 void operator()(false_type) const { 935 __this->__emplace<_Ip>(_Tp(std::forward<_Arg>(__arg))); 936 } 937 __assignment* __this; 938 _Arg&& __arg; 939 } __impl{this, std::forward<_Arg>(__arg)}; 940 __impl(bool_constant < is_nothrow_constructible_v<_Tp, _Arg> || !is_nothrow_move_constructible_v < _Tp >> {}); 941 } 942 } 943 944 template <class _That> 945 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __generic_assign(_That&& __that) { 946 if (this->valueless_by_exception() && __that.valueless_by_exception()) { 947 // do nothing. 948 } else if (__that.valueless_by_exception()) { 949 this->__destroy(); 950 } else { 951 __visitation::__base::__visit_alt_at( 952 __that.index(), 953 [this](auto& __this_alt, auto&& __that_alt) { 954 this->__assign_alt(__this_alt, std::forward<decltype(__that_alt)>(__that_alt).__value); 955 }, 956 *this, 957 std::forward<_That>(__that)); 958 } 959 } 960}; 961 962template <class _Traits, _Trait = _Traits::__move_assignable_trait> 963class _LIBCPP_TEMPLATE_VIS __move_assignment; 964 965# define _LIBCPP_VARIANT_MOVE_ASSIGNMENT(move_assignable_trait, move_assignment_definition) \ 966 template <class... _Types> \ 967 class _LIBCPP_TEMPLATE_VIS __move_assignment<__traits<_Types...>, move_assignable_trait> \ 968 : public __assignment<__traits<_Types...>> { \ 969 using __base_type = __assignment<__traits<_Types...>>; \ 970 \ 971 public: \ 972 using __base_type::__base_type; \ 973 using __base_type::operator=; \ 974 \ 975 _LIBCPP_HIDE_FROM_ABI __move_assignment(const __move_assignment&) = default; \ 976 _LIBCPP_HIDE_FROM_ABI __move_assignment(__move_assignment&&) = default; \ 977 _LIBCPP_HIDE_FROM_ABI ~__move_assignment() = default; \ 978 _LIBCPP_HIDE_FROM_ABI __move_assignment& operator=(const __move_assignment&) = default; \ 979 move_assignment_definition; \ 980 } 981 982_LIBCPP_VARIANT_MOVE_ASSIGNMENT(_Trait::_TriviallyAvailable, 983 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __move_assignment& operator=( 984 __move_assignment&& __that) = default); 985 986_LIBCPP_VARIANT_MOVE_ASSIGNMENT( 987 _Trait::_Available, 988 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __move_assignment& 989 operator=(__move_assignment&& __that) noexcept( 990 __all<(is_nothrow_move_constructible_v<_Types> && is_nothrow_move_assignable_v<_Types>)...>::value) { 991 this->__generic_assign(std::move(__that)); 992 return *this; 993 } _LIBCPP_EAT_SEMICOLON); 994 995_LIBCPP_VARIANT_MOVE_ASSIGNMENT( 996 _Trait::_Unavailable, 997 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __move_assignment& operator=(__move_assignment&&) = delete); 998 999# undef _LIBCPP_VARIANT_MOVE_ASSIGNMENT 1000 1001template <class _Traits, _Trait = _Traits::__copy_assignable_trait> 1002class _LIBCPP_TEMPLATE_VIS __copy_assignment; 1003 1004# define _LIBCPP_VARIANT_COPY_ASSIGNMENT(copy_assignable_trait, copy_assignment_definition) \ 1005 template <class... _Types> \ 1006 class _LIBCPP_TEMPLATE_VIS __copy_assignment<__traits<_Types...>, copy_assignable_trait> \ 1007 : public __move_assignment<__traits<_Types...>> { \ 1008 using __base_type = __move_assignment<__traits<_Types...>>; \ 1009 \ 1010 public: \ 1011 using __base_type::__base_type; \ 1012 using __base_type::operator=; \ 1013 \ 1014 _LIBCPP_HIDE_FROM_ABI __copy_assignment(const __copy_assignment&) = default; \ 1015 _LIBCPP_HIDE_FROM_ABI __copy_assignment(__copy_assignment&&) = default; \ 1016 _LIBCPP_HIDE_FROM_ABI ~__copy_assignment() = default; \ 1017 _LIBCPP_HIDE_FROM_ABI __copy_assignment& operator=(__copy_assignment&&) = default; \ 1018 copy_assignment_definition; \ 1019 } 1020 1021_LIBCPP_VARIANT_COPY_ASSIGNMENT(_Trait::_TriviallyAvailable, 1022 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __copy_assignment& operator=( 1023 const __copy_assignment& __that) = default); 1024 1025_LIBCPP_VARIANT_COPY_ASSIGNMENT( 1026 _Trait::_Available, 1027 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __copy_assignment& 1028 operator=(const __copy_assignment& __that) { 1029 this->__generic_assign(__that); 1030 return *this; 1031 } _LIBCPP_EAT_SEMICOLON); 1032 1033_LIBCPP_VARIANT_COPY_ASSIGNMENT(_Trait::_Unavailable, 1034 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __copy_assignment& operator=( 1035 const __copy_assignment&) = delete); 1036 1037# undef _LIBCPP_VARIANT_COPY_ASSIGNMENT 1038 1039template <class... _Types> 1040class _LIBCPP_TEMPLATE_VIS __impl : public __copy_assignment<__traits<_Types...>> { 1041 using __base_type = __copy_assignment<__traits<_Types...>>; 1042 1043public: 1044 using __base_type::__base_type; // get in_place_index_t constructor & friends 1045 _LIBCPP_HIDE_FROM_ABI __impl(__impl const&) = default; 1046 _LIBCPP_HIDE_FROM_ABI __impl(__impl&&) = default; 1047 _LIBCPP_HIDE_FROM_ABI __impl& operator=(__impl const&) = default; 1048 _LIBCPP_HIDE_FROM_ABI __impl& operator=(__impl&&) = default; 1049 1050 template <size_t _Ip, class _Arg> 1051 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __assign(_Arg&& __arg) { 1052 this->__assign_alt(__access::__base::__get_alt<_Ip>(*this), std::forward<_Arg>(__arg)); 1053 } 1054 1055 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __swap(__impl& __that) { 1056 if (this->valueless_by_exception() && __that.valueless_by_exception()) { 1057 // do nothing. 1058 } else if (this->index() == __that.index()) { 1059 __visitation::__base::__visit_alt_at( 1060 this->index(), 1061 [](auto& __this_alt, auto& __that_alt) { 1062 using std::swap; 1063 swap(__this_alt.__value, __that_alt.__value); 1064 }, 1065 *this, 1066 __that); 1067 } else { 1068 __impl* __lhs = this; 1069 __impl* __rhs = std::addressof(__that); 1070 if (__lhs->__move_nothrow() && !__rhs->__move_nothrow()) { 1071 std::swap(__lhs, __rhs); 1072 } 1073 __impl __tmp(std::move(*__rhs)); 1074# ifndef _LIBCPP_HAS_NO_EXCEPTIONS 1075 if constexpr (__all<is_nothrow_move_constructible_v<_Types>...>::value) { 1076 this->__generic_construct(*__rhs, std::move(*__lhs)); 1077 } else { 1078 // EXTENSION: When the move construction of `__lhs` into `__rhs` throws 1079 // and `__tmp` is nothrow move constructible then we move `__tmp` back 1080 // into `__rhs` and provide the strong exception safety guarantee. 1081 try { 1082 this->__generic_construct(*__rhs, std::move(*__lhs)); 1083 } catch (...) { 1084 if (__tmp.__move_nothrow()) { 1085 this->__generic_construct(*__rhs, std::move(__tmp)); 1086 } 1087 throw; 1088 } 1089 } 1090# else 1091 // this isn't consolidated with the `if constexpr` branch above due to 1092 // `throw` being ill-formed with exceptions disabled even when discarded. 1093 this->__generic_construct(*__rhs, std::move(*__lhs)); 1094# endif 1095 this->__generic_construct(*__lhs, std::move(__tmp)); 1096 } 1097 } 1098 1099private: 1100 constexpr inline _LIBCPP_HIDE_FROM_ABI bool __move_nothrow() const { 1101 constexpr bool __results[] = {is_nothrow_move_constructible_v<_Types>...}; 1102 return this->valueless_by_exception() || __results[this->index()]; 1103 } 1104}; 1105 1106struct __no_narrowing_check { 1107 template <class _Dest, class _Source> 1108 using _Apply = __type_identity<_Dest>; 1109}; 1110 1111struct __narrowing_check { 1112 template <class _Dest> 1113 static auto __test_impl(_Dest (&&)[1]) -> __type_identity<_Dest>; 1114 template <class _Dest, class _Source> 1115 using _Apply _LIBCPP_NODEBUG = decltype(__test_impl<_Dest>({std::declval<_Source>()})); 1116}; 1117 1118template <class _Dest, class _Source> 1119using __check_for_narrowing _LIBCPP_NODEBUG = 1120 typename _If< is_arithmetic<_Dest>::value, __narrowing_check, __no_narrowing_check >::template _Apply<_Dest, 1121 _Source>; 1122 1123template <class _Tp, size_t _Idx> 1124struct __overload { 1125 template <class _Up> 1126 auto operator()(_Tp, _Up&&) const -> __check_for_narrowing<_Tp, _Up>; 1127}; 1128 1129template <class... _Bases> 1130struct __all_overloads : _Bases... { 1131 void operator()() const; 1132 using _Bases::operator()...; 1133}; 1134 1135template <class _IdxSeq> 1136struct __make_overloads_imp; 1137 1138template <size_t... _Idx> 1139struct __make_overloads_imp<__tuple_indices<_Idx...> > { 1140 template <class... _Types> 1141 using _Apply _LIBCPP_NODEBUG = __all_overloads<__overload<_Types, _Idx>...>; 1142}; 1143 1144template <class... _Types> 1145using _MakeOverloads _LIBCPP_NODEBUG = 1146 typename __make_overloads_imp< __make_indices_imp<sizeof...(_Types), 0> >::template _Apply<_Types...>; 1147 1148template <class _Tp, class... _Types> 1149using __best_match_t = typename invoke_result_t<_MakeOverloads<_Types...>, _Tp, _Tp>::type; 1150 1151} // namespace __variant_detail 1152 1153template <class _Visitor, class... _Vs, typename = void_t<decltype(std::__as_variant(std::declval<_Vs>()))...>> 1154_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS constexpr decltype(auto) 1155visit(_Visitor&& __visitor, _Vs&&... __vs); 1156 1157# if _LIBCPP_STD_VER >= 20 1158template <class _Rp, 1159 class _Visitor, 1160 class... _Vs, 1161 typename = void_t<decltype(std::__as_variant(std::declval<_Vs>()))...>> 1162_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS constexpr _Rp 1163visit(_Visitor&& __visitor, _Vs&&... __vs); 1164# endif 1165 1166template <class... _Types> 1167class _LIBCPP_TEMPLATE_VIS _LIBCPP_DECLSPEC_EMPTY_BASES variant 1168 : private __sfinae_ctor_base< __all<is_copy_constructible_v<_Types>...>::value, 1169 __all<is_move_constructible_v<_Types>...>::value>, 1170 private __sfinae_assign_base< 1171 __all<(is_copy_constructible_v<_Types> && is_copy_assignable_v<_Types>)...>::value, 1172 __all<(is_move_constructible_v<_Types> && is_move_assignable_v<_Types>)...>::value> { 1173 static_assert(0 < sizeof...(_Types), "variant must consist of at least one alternative."); 1174 1175 static_assert(__all<!is_array_v<_Types>...>::value, "variant can not have an array type as an alternative."); 1176 1177 static_assert(__all<!is_reference_v<_Types>...>::value, "variant can not have a reference type as an alternative."); 1178 1179 static_assert(__all<!is_void_v<_Types>...>::value, "variant can not have a void type as an alternative."); 1180 1181 using __first_type = variant_alternative_t<0, variant>; 1182 1183public: 1184 using __trivially_relocatable = 1185 conditional_t<_And<__libcpp_is_trivially_relocatable<_Types>...>::value, variant, void>; 1186 1187 template <bool _Dummy = true, 1188 enable_if_t<__dependent_type<is_default_constructible<__first_type>, _Dummy>::value, int> = 0> 1189 _LIBCPP_HIDE_FROM_ABI constexpr variant() noexcept(is_nothrow_default_constructible_v<__first_type>) 1190 : __impl_(in_place_index<0>) {} 1191 1192 _LIBCPP_HIDE_FROM_ABI constexpr variant(const variant&) = default; 1193 _LIBCPP_HIDE_FROM_ABI constexpr variant(variant&&) = default; 1194 1195 template < class _Arg, 1196 enable_if_t<!is_same_v<__remove_cvref_t<_Arg>, variant>, int> = 0, 1197 enable_if_t<!__is_inplace_type<__remove_cvref_t<_Arg>>::value, int> = 0, 1198 enable_if_t<!__is_inplace_index<__remove_cvref_t<_Arg>>::value, int> = 0, 1199 class _Tp = __variant_detail::__best_match_t<_Arg, _Types...>, 1200 size_t _Ip = __find_detail::__find_unambiguous_index_sfinae<_Tp, _Types...>::value, 1201 enable_if_t<is_constructible_v<_Tp, _Arg>, int> = 0> 1202 _LIBCPP_HIDE_FROM_ABI constexpr variant(_Arg&& __arg) noexcept(is_nothrow_constructible_v<_Tp, _Arg>) 1203 : __impl_(in_place_index<_Ip>, std::forward<_Arg>(__arg)) {} 1204 1205 template <size_t _Ip, 1206 class... _Args, 1207 class = enable_if_t<(_Ip < sizeof...(_Types)), int>, 1208 class _Tp = variant_alternative_t<_Ip, variant<_Types...>>, 1209 enable_if_t<is_constructible_v<_Tp, _Args...>, int> = 0> 1210 _LIBCPP_HIDE_FROM_ABI explicit constexpr variant(in_place_index_t<_Ip>, _Args&&... __args) noexcept( 1211 is_nothrow_constructible_v<_Tp, _Args...>) 1212 : __impl_(in_place_index<_Ip>, std::forward<_Args>(__args)...) {} 1213 1214 template < size_t _Ip, 1215 class _Up, 1216 class... _Args, 1217 enable_if_t<(_Ip < sizeof...(_Types)), int> = 0, 1218 class _Tp = variant_alternative_t<_Ip, variant<_Types...>>, 1219 enable_if_t<is_constructible_v<_Tp, initializer_list<_Up>&, _Args...>, int> = 0> 1220 _LIBCPP_HIDE_FROM_ABI explicit constexpr variant( 1221 in_place_index_t<_Ip>, 1222 initializer_list<_Up> __il, 1223 _Args&&... __args) noexcept(is_nothrow_constructible_v<_Tp, initializer_list<_Up>&, _Args...>) 1224 : __impl_(in_place_index<_Ip>, __il, std::forward<_Args>(__args)...) {} 1225 1226 template < class _Tp, 1227 class... _Args, 1228 size_t _Ip = __find_detail::__find_unambiguous_index_sfinae<_Tp, _Types...>::value, 1229 enable_if_t<is_constructible_v<_Tp, _Args...>, int> = 0> 1230 _LIBCPP_HIDE_FROM_ABI explicit constexpr variant(in_place_type_t<_Tp>, _Args&&... __args) noexcept( 1231 is_nothrow_constructible_v<_Tp, _Args...>) 1232 : __impl_(in_place_index<_Ip>, std::forward<_Args>(__args)...) {} 1233 1234 template < class _Tp, 1235 class _Up, 1236 class... _Args, 1237 size_t _Ip = __find_detail::__find_unambiguous_index_sfinae<_Tp, _Types...>::value, 1238 enable_if_t<is_constructible_v<_Tp, initializer_list<_Up>&, _Args...>, int> = 0> 1239 _LIBCPP_HIDE_FROM_ABI explicit constexpr variant( 1240 in_place_type_t<_Tp>, 1241 initializer_list<_Up> __il, 1242 _Args&&... __args) noexcept(is_nothrow_constructible_v<_Tp, initializer_list< _Up>&, _Args...>) 1243 : __impl_(in_place_index<_Ip>, __il, std::forward<_Args>(__args)...) {} 1244 1245 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 ~variant() = default; 1246 1247 _LIBCPP_HIDE_FROM_ABI constexpr variant& operator=(const variant&) = default; 1248 _LIBCPP_HIDE_FROM_ABI constexpr variant& operator=(variant&&) = default; 1249 1250 template < class _Arg, 1251 enable_if_t<!is_same_v<__remove_cvref_t<_Arg>, variant>, int> = 0, 1252 class _Tp = __variant_detail::__best_match_t<_Arg, _Types...>, 1253 size_t _Ip = __find_detail::__find_unambiguous_index_sfinae<_Tp, _Types...>::value, 1254 enable_if_t<is_assignable_v<_Tp&, _Arg> && is_constructible_v<_Tp, _Arg>, int> = 0> 1255 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 variant& 1256 operator=(_Arg&& __arg) noexcept(is_nothrow_assignable_v<_Tp&, _Arg> && is_nothrow_constructible_v<_Tp, _Arg>) { 1257 __impl_.template __assign<_Ip>(std::forward<_Arg>(__arg)); 1258 return *this; 1259 } 1260 1261 template < size_t _Ip, 1262 class... _Args, 1263 enable_if_t<(_Ip < sizeof...(_Types)), int> = 0, 1264 class _Tp = variant_alternative_t<_Ip, variant<_Types...>>, 1265 enable_if_t<is_constructible_v<_Tp, _Args...>, int> = 0> 1266 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Tp& emplace(_Args&&... __args) { 1267 return __impl_.template __emplace<_Ip>(std::forward<_Args>(__args)...); 1268 } 1269 1270 template < size_t _Ip, 1271 class _Up, 1272 class... _Args, 1273 enable_if_t<(_Ip < sizeof...(_Types)), int> = 0, 1274 class _Tp = variant_alternative_t<_Ip, variant<_Types...>>, 1275 enable_if_t<is_constructible_v<_Tp, initializer_list<_Up>&, _Args...>, int> = 0> 1276 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Tp& emplace(initializer_list<_Up> __il, _Args&&... __args) { 1277 return __impl_.template __emplace<_Ip>(__il, std::forward<_Args>(__args)...); 1278 } 1279 1280 template < class _Tp, 1281 class... _Args, 1282 size_t _Ip = __find_detail::__find_unambiguous_index_sfinae<_Tp, _Types...>::value, 1283 enable_if_t<is_constructible_v<_Tp, _Args...>, int> = 0> 1284 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Tp& emplace(_Args&&... __args) { 1285 return __impl_.template __emplace<_Ip>(std::forward<_Args>(__args)...); 1286 } 1287 1288 template < class _Tp, 1289 class _Up, 1290 class... _Args, 1291 size_t _Ip = __find_detail::__find_unambiguous_index_sfinae<_Tp, _Types...>::value, 1292 enable_if_t<is_constructible_v<_Tp, initializer_list<_Up>&, _Args...>, int> = 0> 1293 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Tp& emplace(initializer_list<_Up> __il, _Args&&... __args) { 1294 return __impl_.template __emplace<_Ip>(__il, std::forward<_Args>(__args)...); 1295 } 1296 1297 _LIBCPP_HIDE_FROM_ABI constexpr bool valueless_by_exception() const noexcept { 1298 return __impl_.valueless_by_exception(); 1299 } 1300 1301 _LIBCPP_HIDE_FROM_ABI constexpr size_t index() const noexcept { return __impl_.index(); } 1302 1303 template < bool _Dummy = true, 1304 enable_if_t< __all<(__dependent_type<is_move_constructible<_Types>, _Dummy>::value && 1305 __dependent_type<is_swappable<_Types>, _Dummy>::value)...>::value, 1306 int> = 0> 1307 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void swap(variant& __that) noexcept( 1308 __all<(is_nothrow_move_constructible_v<_Types> && is_nothrow_swappable_v<_Types>)...>::value) { 1309 __impl_.__swap(__that.__impl_); 1310 } 1311 1312# if _LIBCPP_STD_VER >= 26 && defined(_LIBCPP_HAS_EXPLICIT_THIS_PARAMETER) 1313 // Helper class to implement [variant.visit]/10 1314 // Constraints: The call to visit does not use an explicit template-argument-list 1315 // that begins with a type template-argument. 1316 struct __variant_visit_barrier_tag { 1317 _LIBCPP_HIDE_FROM_ABI explicit __variant_visit_barrier_tag() = default; 1318 }; 1319 1320 template <__variant_visit_barrier_tag = __variant_visit_barrier_tag{}, class _Self, class _Visitor> 1321 _LIBCPP_HIDE_FROM_ABI constexpr decltype(auto) visit(this _Self&& __self, _Visitor&& __visitor) { 1322 using _VariantT = _OverrideRef<_Self&&, _CopyConst<remove_reference_t<_Self>, variant>>; 1323 return std::visit(std::forward<_Visitor>(__visitor), (_VariantT)__self); 1324 } 1325 1326 template <class _Rp, class _Self, class _Visitor> 1327 _LIBCPP_HIDE_FROM_ABI constexpr _Rp visit(this _Self&& __self, _Visitor&& __visitor) { 1328 using _VariantT = _OverrideRef<_Self&&, _CopyConst<remove_reference_t<_Self>, variant>>; 1329 return std::visit<_Rp>(std::forward<_Visitor>(__visitor), (_VariantT)__self); 1330 } 1331# endif 1332 1333private: 1334 __variant_detail::__impl<_Types...> __impl_; 1335 1336 friend struct __variant_detail::__access::__variant; 1337 friend struct __variant_detail::__visitation::__variant; 1338}; 1339 1340template <size_t _Ip, class... _Types> 1341_LIBCPP_HIDE_FROM_ABI constexpr bool __holds_alternative(const variant<_Types...>& __v) noexcept { 1342 return __v.index() == _Ip; 1343} 1344 1345template <class _Tp, class... _Types> 1346_LIBCPP_HIDE_FROM_ABI constexpr bool holds_alternative(const variant<_Types...>& __v) noexcept { 1347 return std::__holds_alternative<__find_exactly_one_t<_Tp, _Types...>::value>(__v); 1348} 1349 1350template <size_t _Ip, class _Vp> 1351_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS constexpr auto&& __generic_get(_Vp&& __v) { 1352 using __variant_detail::__access::__variant; 1353 if (!std::__holds_alternative<_Ip>(__v)) { 1354 __throw_bad_variant_access(); 1355 } 1356 return __variant::__get_alt<_Ip>(std::forward<_Vp>(__v)).__value; 1357} 1358 1359template <size_t _Ip, class... _Types> 1360_LIBCPP_HIDE_FROM_ABI 1361_LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS constexpr variant_alternative_t<_Ip, variant<_Types...>>& 1362get(variant<_Types...>& __v) { 1363 static_assert(_Ip < sizeof...(_Types)); 1364 static_assert(!is_void_v<variant_alternative_t<_Ip, variant<_Types...>>>); 1365 return std::__generic_get<_Ip>(__v); 1366} 1367 1368template <size_t _Ip, class... _Types> 1369_LIBCPP_HIDE_FROM_ABI 1370_LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS constexpr variant_alternative_t<_Ip, variant<_Types...>>&& 1371get(variant<_Types...>&& __v) { 1372 static_assert(_Ip < sizeof...(_Types)); 1373 static_assert(!is_void_v<variant_alternative_t<_Ip, variant<_Types...>>>); 1374 return std::__generic_get<_Ip>(std::move(__v)); 1375} 1376 1377template <size_t _Ip, class... _Types> 1378_LIBCPP_HIDE_FROM_ABI 1379_LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS constexpr const variant_alternative_t<_Ip, variant<_Types...>>& 1380get(const variant<_Types...>& __v) { 1381 static_assert(_Ip < sizeof...(_Types)); 1382 static_assert(!is_void_v<variant_alternative_t<_Ip, variant<_Types...>>>); 1383 return std::__generic_get<_Ip>(__v); 1384} 1385 1386template <size_t _Ip, class... _Types> 1387_LIBCPP_HIDE_FROM_ABI 1388_LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS constexpr const variant_alternative_t<_Ip, variant<_Types...>>&& 1389get(const variant<_Types...>&& __v) { 1390 static_assert(_Ip < sizeof...(_Types)); 1391 static_assert(!is_void_v<variant_alternative_t<_Ip, variant<_Types...>>>); 1392 return std::__generic_get<_Ip>(std::move(__v)); 1393} 1394 1395template <class _Tp, class... _Types> 1396_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS constexpr _Tp& get(variant<_Types...>& __v) { 1397 static_assert(!is_void_v<_Tp>); 1398 return std::get<__find_exactly_one_t<_Tp, _Types...>::value>(__v); 1399} 1400 1401template <class _Tp, class... _Types> 1402_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS constexpr _Tp&& get(variant<_Types...>&& __v) { 1403 static_assert(!is_void_v<_Tp>); 1404 return std::get<__find_exactly_one_t<_Tp, _Types...>::value>(std::move(__v)); 1405} 1406 1407template <class _Tp, class... _Types> 1408_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS constexpr const _Tp& 1409get(const variant<_Types...>& __v) { 1410 static_assert(!is_void_v<_Tp>); 1411 return std::get<__find_exactly_one_t<_Tp, _Types...>::value>(__v); 1412} 1413 1414template <class _Tp, class... _Types> 1415_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS constexpr const _Tp&& 1416get(const variant<_Types...>&& __v) { 1417 static_assert(!is_void_v<_Tp>); 1418 return std::get<__find_exactly_one_t<_Tp, _Types...>::value>(std::move(__v)); 1419} 1420 1421template <size_t _Ip, class _Vp> 1422_LIBCPP_HIDE_FROM_ABI constexpr auto* __generic_get_if(_Vp* __v) noexcept { 1423 using __variant_detail::__access::__variant; 1424 return __v && std::__holds_alternative<_Ip>(*__v) ? std::addressof(__variant::__get_alt<_Ip>(*__v).__value) : nullptr; 1425} 1426 1427template <size_t _Ip, class... _Types> 1428_LIBCPP_HIDE_FROM_ABI constexpr add_pointer_t<variant_alternative_t<_Ip, variant<_Types...>>> 1429get_if(variant<_Types...>* __v) noexcept { 1430 static_assert(_Ip < sizeof...(_Types)); 1431 static_assert(!is_void_v<variant_alternative_t<_Ip, variant<_Types...>>>); 1432 return std::__generic_get_if<_Ip>(__v); 1433} 1434 1435template <size_t _Ip, class... _Types> 1436_LIBCPP_HIDE_FROM_ABI constexpr add_pointer_t<const variant_alternative_t<_Ip, variant<_Types...>>> 1437get_if(const variant<_Types...>* __v) noexcept { 1438 static_assert(_Ip < sizeof...(_Types)); 1439 static_assert(!is_void_v<variant_alternative_t<_Ip, variant<_Types...>>>); 1440 return std::__generic_get_if<_Ip>(__v); 1441} 1442 1443template <class _Tp, class... _Types> 1444_LIBCPP_HIDE_FROM_ABI constexpr add_pointer_t<_Tp> get_if(variant<_Types...>* __v) noexcept { 1445 static_assert(!is_void_v<_Tp>); 1446 return std::get_if<__find_exactly_one_t<_Tp, _Types...>::value>(__v); 1447} 1448 1449template <class _Tp, class... _Types> 1450_LIBCPP_HIDE_FROM_ABI constexpr add_pointer_t<const _Tp> get_if(const variant<_Types...>* __v) noexcept { 1451 static_assert(!is_void_v<_Tp>); 1452 return std::get_if<__find_exactly_one_t<_Tp, _Types...>::value>(__v); 1453} 1454 1455template <class _Operator> 1456struct __convert_to_bool { 1457 template <class _T1, class _T2> 1458 _LIBCPP_HIDE_FROM_ABI constexpr bool operator()(_T1&& __t1, _T2&& __t2) const { 1459 static_assert(is_convertible<decltype(_Operator{}(std::forward<_T1>(__t1), std::forward<_T2>(__t2))), bool>::value, 1460 "the relational operator does not return a type which is implicitly convertible to bool"); 1461 return _Operator{}(std::forward<_T1>(__t1), std::forward<_T2>(__t2)); 1462 } 1463}; 1464 1465template <class... _Types> 1466_LIBCPP_HIDE_FROM_ABI constexpr bool operator==(const variant<_Types...>& __lhs, const variant<_Types...>& __rhs) { 1467 using __variant_detail::__visitation::__variant; 1468 if (__lhs.index() != __rhs.index()) 1469 return false; 1470 if (__lhs.valueless_by_exception()) 1471 return true; 1472 return __variant::__visit_value_at(__lhs.index(), __convert_to_bool<equal_to<>>{}, __lhs, __rhs); 1473} 1474 1475# if _LIBCPP_STD_VER >= 20 1476 1477template <class... _Types> 1478 requires(three_way_comparable<_Types> && ...) 1479_LIBCPP_HIDE_FROM_ABI constexpr common_comparison_category_t<compare_three_way_result_t<_Types>...> 1480operator<=>(const variant<_Types...>& __lhs, const variant<_Types...>& __rhs) { 1481 using __variant_detail::__visitation::__variant; 1482 using __result_t = common_comparison_category_t<compare_three_way_result_t<_Types>...>; 1483 if (__lhs.valueless_by_exception() && __rhs.valueless_by_exception()) 1484 return strong_ordering::equal; 1485 if (__lhs.valueless_by_exception()) 1486 return strong_ordering::less; 1487 if (__rhs.valueless_by_exception()) 1488 return strong_ordering::greater; 1489 if (auto __c = __lhs.index() <=> __rhs.index(); __c != 0) 1490 return __c; 1491 auto __three_way = []<class _Type>(const _Type& __v, const _Type& __w) -> __result_t { return __v <=> __w; }; 1492 return __variant::__visit_value_at(__lhs.index(), __three_way, __lhs, __rhs); 1493} 1494 1495# endif // _LIBCPP_STD_VER >= 20 1496 1497template <class... _Types> 1498_LIBCPP_HIDE_FROM_ABI constexpr bool operator!=(const variant<_Types...>& __lhs, const variant<_Types...>& __rhs) { 1499 using __variant_detail::__visitation::__variant; 1500 if (__lhs.index() != __rhs.index()) 1501 return true; 1502 if (__lhs.valueless_by_exception()) 1503 return false; 1504 return __variant::__visit_value_at(__lhs.index(), __convert_to_bool<not_equal_to<>>{}, __lhs, __rhs); 1505} 1506 1507template <class... _Types> 1508_LIBCPP_HIDE_FROM_ABI constexpr bool operator<(const variant<_Types...>& __lhs, const variant<_Types...>& __rhs) { 1509 using __variant_detail::__visitation::__variant; 1510 if (__rhs.valueless_by_exception()) 1511 return false; 1512 if (__lhs.valueless_by_exception()) 1513 return true; 1514 if (__lhs.index() < __rhs.index()) 1515 return true; 1516 if (__lhs.index() > __rhs.index()) 1517 return false; 1518 return __variant::__visit_value_at(__lhs.index(), __convert_to_bool<less<>>{}, __lhs, __rhs); 1519} 1520 1521template <class... _Types> 1522_LIBCPP_HIDE_FROM_ABI constexpr bool operator>(const variant<_Types...>& __lhs, const variant<_Types...>& __rhs) { 1523 using __variant_detail::__visitation::__variant; 1524 if (__lhs.valueless_by_exception()) 1525 return false; 1526 if (__rhs.valueless_by_exception()) 1527 return true; 1528 if (__lhs.index() > __rhs.index()) 1529 return true; 1530 if (__lhs.index() < __rhs.index()) 1531 return false; 1532 return __variant::__visit_value_at(__lhs.index(), __convert_to_bool<greater<>>{}, __lhs, __rhs); 1533} 1534 1535template <class... _Types> 1536_LIBCPP_HIDE_FROM_ABI constexpr bool operator<=(const variant<_Types...>& __lhs, const variant<_Types...>& __rhs) { 1537 using __variant_detail::__visitation::__variant; 1538 if (__lhs.valueless_by_exception()) 1539 return true; 1540 if (__rhs.valueless_by_exception()) 1541 return false; 1542 if (__lhs.index() < __rhs.index()) 1543 return true; 1544 if (__lhs.index() > __rhs.index()) 1545 return false; 1546 return __variant::__visit_value_at(__lhs.index(), __convert_to_bool<less_equal<>>{}, __lhs, __rhs); 1547} 1548 1549template <class... _Types> 1550_LIBCPP_HIDE_FROM_ABI constexpr bool operator>=(const variant<_Types...>& __lhs, const variant<_Types...>& __rhs) { 1551 using __variant_detail::__visitation::__variant; 1552 if (__rhs.valueless_by_exception()) 1553 return true; 1554 if (__lhs.valueless_by_exception()) 1555 return false; 1556 if (__lhs.index() > __rhs.index()) 1557 return true; 1558 if (__lhs.index() < __rhs.index()) 1559 return false; 1560 return __variant::__visit_value_at(__lhs.index(), __convert_to_bool<greater_equal<>>{}, __lhs, __rhs); 1561} 1562 1563template <class... _Vs> 1564_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS constexpr void __throw_if_valueless(_Vs&&... __vs) { 1565 const bool __valueless = (... || std::__as_variant(__vs).valueless_by_exception()); 1566 if (__valueless) { 1567 __throw_bad_variant_access(); 1568 } 1569} 1570 1571template < class _Visitor, class... _Vs, typename> 1572_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS constexpr decltype(auto) 1573visit(_Visitor&& __visitor, _Vs&&... __vs) { 1574 using __variant_detail::__visitation::__variant; 1575 std::__throw_if_valueless(std::forward<_Vs>(__vs)...); 1576 return __variant::__visit_value(std::forward<_Visitor>(__visitor), std::forward<_Vs>(__vs)...); 1577} 1578 1579# if _LIBCPP_STD_VER >= 20 1580template < class _Rp, class _Visitor, class... _Vs, typename> 1581_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS constexpr _Rp 1582visit(_Visitor&& __visitor, _Vs&&... __vs) { 1583 using __variant_detail::__visitation::__variant; 1584 std::__throw_if_valueless(std::forward<_Vs>(__vs)...); 1585 return __variant::__visit_value<_Rp>(std::forward<_Visitor>(__visitor), std::forward<_Vs>(__vs)...); 1586} 1587# endif 1588 1589template <class... _Types> 1590_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 auto 1591swap(variant<_Types...>& __lhs, 1592 variant<_Types...>& __rhs) noexcept(noexcept(__lhs.swap(__rhs))) -> decltype(__lhs.swap(__rhs)) { 1593 return __lhs.swap(__rhs); 1594} 1595 1596template <class... _Types> 1597struct _LIBCPP_TEMPLATE_VIS hash< __enable_hash_helper<variant<_Types...>, remove_const_t<_Types>...>> { 1598 using argument_type = variant<_Types...>; 1599 using result_type = size_t; 1600 1601 _LIBCPP_HIDE_FROM_ABI result_type operator()(const argument_type& __v) const { 1602 using __variant_detail::__visitation::__variant; 1603 size_t __res = 1604 __v.valueless_by_exception() 1605 ? 299792458 // Random value chosen by the universe upon creation 1606 : __variant::__visit_alt( 1607 [](const auto& __alt) { 1608 using __alt_type = __remove_cvref_t<decltype(__alt)>; 1609 using __value_type = remove_const_t< typename __alt_type::__value_type>; 1610 return hash<__value_type>{}(__alt.__value); 1611 }, 1612 __v); 1613 return std::__hash_combine(__res, hash<size_t>{}(__v.index())); 1614 } 1615}; 1616 1617// __unchecked_get is the same as std::get, except, it is UB to use it with the wrong 1618// type whereas std::get will throw or returning nullptr. This makes it faster than 1619// std::get. 1620template <size_t _Ip, class _Vp> 1621_LIBCPP_HIDE_FROM_ABI constexpr auto&& __unchecked_get(_Vp&& __v) noexcept { 1622 using __variant_detail::__access::__variant; 1623 return __variant::__get_alt<_Ip>(std::forward<_Vp>(__v)).__value; 1624} 1625 1626template <class _Tp, class... _Types> 1627_LIBCPP_HIDE_FROM_ABI constexpr auto&& __unchecked_get(const variant<_Types...>& __v) noexcept { 1628 return std::__unchecked_get<__find_exactly_one_t<_Tp, _Types...>::value>(__v); 1629} 1630 1631template <class _Tp, class... _Types> 1632_LIBCPP_HIDE_FROM_ABI constexpr auto&& __unchecked_get(variant<_Types...>& __v) noexcept { 1633 return std::__unchecked_get<__find_exactly_one_t<_Tp, _Types...>::value>(__v); 1634} 1635 1636#endif // _LIBCPP_STD_VER >= 17 1637 1638_LIBCPP_END_NAMESPACE_STD 1639 1640_LIBCPP_POP_MACROS 1641 1642#if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES) && _LIBCPP_STD_VER <= 20 1643# include <exception> 1644# include <tuple> 1645# include <type_traits> 1646# include <typeinfo> 1647# include <utility> 1648#endif 1649 1650#endif // _LIBCPP_VARIANT 1651