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0001 // -*- C++ -*-
0002 //===----------------------------------------------------------------------===//
0003 //
0004 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
0005 // See https://llvm.org/LICENSE.txt for license information.
0006 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
0007 //
0008 //===----------------------------------------------------------------------===//
0009
0010 #ifndef _LIBCPP_VARIANT
0011 #define _LIBCPP_VARIANT
0012
0013 /*
0014 variant synopsis
0015
0016 namespace std {
0017
0018 // 20.7.2, class template variant
0019 template <class... Types>
0020 class variant {
0021 public:
0022
0023 // 20.7.2.1, constructors
0024 constexpr variant() noexcept(see below);
0025 constexpr variant(const variant&);
0026 constexpr variant(variant&&) noexcept(see below);
0027
0028 template <class T> constexpr variant(T&&) noexcept(see below);
0029
0030 template <class T, class... Args>
0031 constexpr explicit variant(in_place_type_t<T>, Args&&...);
0032
0033 template <class T, class U, class... Args>
0034 constexpr explicit variant(
0035 in_place_type_t<T>, initializer_list<U>, Args&&...);
0036
0037 template <size_t I, class... Args>
0038 constexpr explicit variant(in_place_index_t<I>, Args&&...);
0039
0040 template <size_t I, class U, class... Args>
0041 constexpr explicit variant(
0042 in_place_index_t<I>, initializer_list<U>, Args&&...);
0043
0044 // 20.7.2.2, destructor
0045 constexpr ~variant(); // constexpr since c++20
0046
0047 // 20.7.2.3, assignment
0048 constexpr variant& operator=(const variant&);
0049 constexpr variant& operator=(variant&&) noexcept(see below);
0050
0051 template <class T>
0052 constexpr variant& operator=(T&&) noexcept(see below); // constexpr since c++20
0053
0054 // 20.7.2.4, modifiers
0055 template <class T, class... Args>
0056 constexpr T& emplace(Args&&...); // constexpr since c++20
0057
0058 template <class T, class U, class... Args>
0059 constexpr T& emplace(initializer_list<U>, Args&&...); // constexpr since c++20
0060
0061 template <size_t I, class... Args>
0062 constexpr variant_alternative_t<I, variant>& emplace(Args&&...); // constexpr since c++20
0063
0064 template <size_t I, class U, class... Args>
0065 constexpr variant_alternative_t<I, variant>&
0066 emplace(initializer_list<U>, Args&&...); // constexpr since c++20
0067
0068 // 20.7.2.5, value status
0069 constexpr bool valueless_by_exception() const noexcept;
0070 constexpr size_t index() const noexcept;
0071
0072 // 20.7.2.6, swap
0073 void swap(variant&) noexcept(see below);
0074
0075 // [variant.visit], visitation
0076 template<class Self, class Visitor>
0077 constexpr decltype(auto) visit(this Self&&, Visitor&&); // Since C++26
0078 template<class R, class Self, class Visitor>
0079 constexpr R visit(this Self&&, Visitor&&); // Since C++26
0080 };
0081
0082 // 20.7.3, variant helper classes
0083 template <class T> struct variant_size; // undefined
0084
0085 template <class T>
0086 inline constexpr size_t variant_size_v = variant_size<T>::value;
0087
0088 template <class T> struct variant_size<const T>;
0089 template <class T> struct variant_size<volatile T>;
0090 template <class T> struct variant_size<const volatile T>;
0091
0092 template <class... Types>
0093 struct variant_size<variant<Types...>>;
0094
0095 template <size_t I, class T> struct variant_alternative; // undefined
0096
0097 template <size_t I, class T>
0098 using variant_alternative_t = typename variant_alternative<I, T>::type;
0099
0100 template <size_t I, class T> struct variant_alternative<I, const T>;
0101 template <size_t I, class T> struct variant_alternative<I, volatile T>;
0102 template <size_t I, class T> struct variant_alternative<I, const volatile T>;
0103
0104 template <size_t I, class... Types>
0105 struct variant_alternative<I, variant<Types...>>;
0106
0107 inline constexpr size_t variant_npos = -1;
0108
0109 // 20.7.4, value access
0110 template <class T, class... Types>
0111 constexpr bool holds_alternative(const variant<Types...>&) noexcept;
0112
0113 template <size_t I, class... Types>
0114 constexpr variant_alternative_t<I, variant<Types...>>&
0115 get(variant<Types...>&);
0116
0117 template <size_t I, class... Types>
0118 constexpr variant_alternative_t<I, variant<Types...>>&&
0119 get(variant<Types...>&&);
0120
0121 template <size_t I, class... Types>
0122 constexpr variant_alternative_t<I, variant<Types...>> const&
0123 get(const variant<Types...>&);
0124
0125 template <size_t I, class... Types>
0126 constexpr variant_alternative_t<I, variant<Types...>> const&&
0127 get(const variant<Types...>&&);
0128
0129 template <class T, class... Types>
0130 constexpr T& get(variant<Types...>&);
0131
0132 template <class T, class... Types>
0133 constexpr T&& get(variant<Types...>&&);
0134
0135 template <class T, class... Types>
0136 constexpr const T& get(const variant<Types...>&);
0137
0138 template <class T, class... Types>
0139 constexpr const T&& get(const variant<Types...>&&);
0140
0141 template <size_t I, class... Types>
0142 constexpr add_pointer_t<variant_alternative_t<I, variant<Types...>>>
0143 get_if(variant<Types...>*) noexcept;
0144
0145 template <size_t I, class... Types>
0146 constexpr add_pointer_t<const variant_alternative_t<I, variant<Types...>>>
0147 get_if(const variant<Types...>*) noexcept;
0148
0149 template <class T, class... Types>
0150 constexpr add_pointer_t<T>
0151 get_if(variant<Types...>*) noexcept;
0152
0153 template <class T, class... Types>
0154 constexpr add_pointer_t<const T>
0155 get_if(const variant<Types...>*) noexcept;
0156
0157 // 20.7.5, relational operators
0158 template <class... Types>
0159 constexpr bool operator==(const variant<Types...>&, const variant<Types...>&);
0160
0161 template <class... Types>
0162 constexpr bool operator!=(const variant<Types...>&, const variant<Types...>&);
0163
0164 template <class... Types>
0165 constexpr bool operator<(const variant<Types...>&, const variant<Types...>&);
0166
0167 template <class... Types>
0168 constexpr bool operator>(const variant<Types...>&, const variant<Types...>&);
0169
0170 template <class... Types>
0171 constexpr bool operator<=(const variant<Types...>&, const variant<Types...>&);
0172
0173 template <class... Types>
0174 constexpr bool operator>=(const variant<Types...>&, const variant<Types...>&);
0175
0176 template <class... Types> requires (three_way_comparable<Types> && ...)
0177 constexpr common_comparison_category_t<compare_three_way_result_t<Types>...>
0178 operator<=>(const variant<Types...>&, const variant<Types...>&); // since C++20
0179
0180 // 20.7.6, visitation
0181 template <class Visitor, class... Variants>
0182 constexpr see below visit(Visitor&&, Variants&&...);
0183
0184 template <class R, class Visitor, class... Variants>
0185 constexpr R visit(Visitor&&, Variants&&...); // since C++20
0186
0187 // 20.7.7, class monostate
0188 struct monostate;
0189
0190 // 20.7.8, monostate relational operators
0191 constexpr bool operator==(monostate, monostate) noexcept;
0192 constexpr bool operator!=(monostate, monostate) noexcept; // until C++20
0193 constexpr bool operator<(monostate, monostate) noexcept; // until C++20
0194 constexpr bool operator>(monostate, monostate) noexcept; // until C++20
0195 constexpr bool operator<=(monostate, monostate) noexcept; // until C++20
0196 constexpr bool operator>=(monostate, monostate) noexcept; // until C++20
0197 constexpr strong_ordering operator<=>(monostate, monostate) noexcept; // since C++20
0198
0199 // 20.7.9, specialized algorithms
0200 template <class... Types>
0201 void swap(variant<Types...>&, variant<Types...>&) noexcept(see below);
0202
0203 // 20.7.10, class bad_variant_access
0204 class bad_variant_access;
0205
0206 // 20.7.11, hash support
0207 template <class T> struct hash;
0208 template <class... Types> struct hash<variant<Types...>>;
0209 template <> struct hash<monostate>;
0210
0211 } // namespace std
0212
0213 */
0214
0215 #if __cplusplus < 201103L && defined(_LIBCPP_USE_FROZEN_CXX03_HEADERS)
0216 # include <__cxx03/variant>
0217 #else
0218 # include <__compare/common_comparison_category.h>
0219 # include <__compare/compare_three_way_result.h>
0220 # include <__compare/ordering.h>
0221 # include <__compare/three_way_comparable.h>
0222 # include <__config>
0223 # include <__exception/exception.h>
0224 # include <__functional/hash.h>
0225 # include <__functional/operations.h>
0226 # include <__functional/unary_function.h>
0227 # include <__fwd/variant.h>
0228 # include <__memory/addressof.h>
0229 # include <__memory/construct_at.h>
0230 # include <__tuple/find_index.h>
0231 # include <__tuple/sfinae_helpers.h>
0232 # include <__type_traits/add_cv_quals.h>
0233 # include <__type_traits/add_pointer.h>
0234 # include <__type_traits/common_type.h>
0235 # include <__type_traits/conditional.h>
0236 # include <__type_traits/conjunction.h>
0237 # include <__type_traits/decay.h>
0238 # include <__type_traits/dependent_type.h>
0239 # include <__type_traits/enable_if.h>
0240 # include <__type_traits/invoke.h>
0241 # include <__type_traits/is_array.h>
0242 # include <__type_traits/is_assignable.h>
0243 # include <__type_traits/is_constructible.h>
0244 # include <__type_traits/is_convertible.h>
0245 # include <__type_traits/is_destructible.h>
0246 # include <__type_traits/is_nothrow_assignable.h>
0247 # include <__type_traits/is_nothrow_constructible.h>
0248 # include <__type_traits/is_reference.h>
0249 # include <__type_traits/is_same.h>
0250 # include <__type_traits/is_swappable.h>
0251 # include <__type_traits/is_trivially_assignable.h>
0252 # include <__type_traits/is_trivially_constructible.h>
0253 # include <__type_traits/is_trivially_destructible.h>
0254 # include <__type_traits/is_trivially_relocatable.h>
0255 # include <__type_traits/is_void.h>
0256 # include <__type_traits/remove_const.h>
0257 # include <__type_traits/remove_cvref.h>
0258 # include <__type_traits/remove_reference.h>
0259 # include <__type_traits/type_identity.h>
0260 # include <__type_traits/void_t.h>
0261 # include <__utility/declval.h>
0262 # include <__utility/forward.h>
0263 # include <__utility/forward_like.h>
0264 # include <__utility/in_place.h>
0265 # include <__utility/integer_sequence.h>
0266 # include <__utility/move.h>
0267 # include <__utility/swap.h>
0268 # include <__variant/monostate.h>
0269 # include <__verbose_abort>
0270 # include <initializer_list>
0271 # include <limits>
0272 # include <version>
0273
0274 // standard-mandated includes
0275
0276 // [variant.syn]
0277 # include <compare>
0278
0279 # if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
0280 # pragma GCC system_header
0281 # endif
0282
0283 _LIBCPP_PUSH_MACROS
0284 # include <__undef_macros>
0285
0286 namespace std { // explicitly not using versioning namespace
0287
0288 class _LIBCPP_EXPORTED_FROM_ABI _LIBCPP_AVAILABILITY_BAD_VARIANT_ACCESS bad_variant_access : public exception {
0289 public:
0290 const char* what() const _NOEXCEPT override;
0291 };
0292
0293 } // namespace std
0294
0295 _LIBCPP_BEGIN_NAMESPACE_STD
0296
0297 # if _LIBCPP_STD_VER >= 17
0298
0299 // Light N-dimensional array of function pointers. Used in place of std::array to avoid
0300 // adding a dependency.
0301 template <class _Tp, size_t _Size>
0302 struct __farray {
0303 static_assert(_Size > 0, "N-dimensional array should never be empty in std::visit");
0304 _Tp __buf_[_Size] = {};
0305
0306 _LIBCPP_HIDE_FROM_ABI constexpr const _Tp& operator[](size_t __n) const noexcept { return __buf_[__n]; }
0307 };
0308
0309 [[noreturn]] inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS void
0310 __throw_bad_variant_access() {
0311 # if _LIBCPP_HAS_EXCEPTIONS
0312 throw bad_variant_access();
0313 # else
0314 _LIBCPP_VERBOSE_ABORT("bad_variant_access was thrown in -fno-exceptions mode");
0315 # endif
0316 }
0317
0318 // variant_size
0319 template <class _Tp>
0320 struct _LIBCPP_TEMPLATE_VIS variant_size<const _Tp> : variant_size<_Tp> {};
0321
0322 template <class _Tp>
0323 struct _LIBCPP_TEMPLATE_VIS variant_size<volatile _Tp> : variant_size<_Tp> {};
0324
0325 template <class _Tp>
0326 struct _LIBCPP_TEMPLATE_VIS variant_size<const volatile _Tp> : variant_size<_Tp> {};
0327
0328 template <class... _Types>
0329 struct _LIBCPP_TEMPLATE_VIS variant_size<variant<_Types...>> : integral_constant<size_t, sizeof...(_Types)> {};
0330
0331 // variant_alternative
0332 template <size_t _Ip, class _Tp>
0333 struct _LIBCPP_TEMPLATE_VIS variant_alternative<_Ip, const _Tp> : add_const<variant_alternative_t<_Ip, _Tp>> {};
0334
0335 template <size_t _Ip, class _Tp>
0336 struct _LIBCPP_TEMPLATE_VIS variant_alternative<_Ip, volatile _Tp> : add_volatile<variant_alternative_t<_Ip, _Tp>> {};
0337
0338 template <size_t _Ip, class _Tp>
0339 struct _LIBCPP_TEMPLATE_VIS variant_alternative<_Ip, const volatile _Tp> : add_cv<variant_alternative_t<_Ip, _Tp>> {};
0340
0341 template <size_t _Ip, class... _Types>
0342 struct _LIBCPP_TEMPLATE_VIS variant_alternative<_Ip, variant<_Types...>> {
0343 static_assert(_Ip < sizeof...(_Types), "Index out of bounds in std::variant_alternative<>");
0344 using type = __type_pack_element<_Ip, _Types...>;
0345 };
0346
0347 template <size_t _NumAlternatives>
0348 _LIBCPP_HIDE_FROM_ABI constexpr auto __choose_index_type() {
0349 # ifdef _LIBCPP_ABI_VARIANT_INDEX_TYPE_OPTIMIZATION
0350 if constexpr (_NumAlternatives < numeric_limits<unsigned char>::max())
0351 return static_cast<unsigned char>(0);
0352 else if constexpr (_NumAlternatives < numeric_limits<unsigned short>::max())
0353 return static_cast<unsigned short>(0);
0354 else
0355 # endif // _LIBCPP_ABI_VARIANT_INDEX_TYPE_OPTIMIZATION
0356 return static_cast<unsigned int>(0);
0357 }
0358
0359 template <size_t _NumAlts>
0360 using __variant_index_t _LIBCPP_NODEBUG = decltype(std::__choose_index_type<_NumAlts>());
0361
0362 template <class _IndexType>
0363 constexpr _IndexType __variant_npos = static_cast<_IndexType>(-1);
0364
0365 template <class... _Types>
0366 _LIBCPP_HIDE_FROM_ABI constexpr variant<_Types...>& __as_variant(variant<_Types...>& __vs) noexcept {
0367 return __vs;
0368 }
0369
0370 template <class... _Types>
0371 _LIBCPP_HIDE_FROM_ABI constexpr const variant<_Types...>& __as_variant(const variant<_Types...>& __vs) noexcept {
0372 return __vs;
0373 }
0374
0375 template <class... _Types>
0376 _LIBCPP_HIDE_FROM_ABI constexpr variant<_Types...>&& __as_variant(variant<_Types...>&& __vs) noexcept {
0377 return std::move(__vs);
0378 }
0379
0380 template <class... _Types>
0381 _LIBCPP_HIDE_FROM_ABI constexpr const variant<_Types...>&& __as_variant(const variant<_Types...>&& __vs) noexcept {
0382 return std::move(__vs);
0383 }
0384
0385 namespace __find_detail {
0386
0387 template <class _Tp, class... _Types>
0388 _LIBCPP_HIDE_FROM_ABI constexpr size_t __find_index() {
0389 constexpr bool __matches[] = {is_same_v<_Tp, _Types>...};
0390 size_t __result = __not_found;
0391 for (size_t __i = 0; __i < sizeof...(_Types); ++__i) {
0392 if (__matches[__i]) {
0393 if (__result != __not_found) {
0394 return __ambiguous;
0395 }
0396 __result = __i;
0397 }
0398 }
0399 return __result;
0400 }
0401
0402 template <size_t _Index>
0403 struct __find_unambiguous_index_sfinae_impl : integral_constant<size_t, _Index> {};
0404
0405 template <>
0406 struct __find_unambiguous_index_sfinae_impl<__not_found> {};
0407
0408 template <>
0409 struct __find_unambiguous_index_sfinae_impl<__ambiguous> {};
0410
0411 template <class _Tp, class... _Types>
0412 struct __find_unambiguous_index_sfinae : __find_unambiguous_index_sfinae_impl<__find_index<_Tp, _Types...>()> {};
0413
0414 } // namespace __find_detail
0415
0416 namespace __variant_detail {
0417
0418 struct __valueless_t {};
0419
0420 enum class _Trait { _TriviallyAvailable, _Available, _Unavailable };
0421
0422 template <typename _Tp, template <typename> class _IsTriviallyAvailable, template <typename> class _IsAvailable>
0423 constexpr _Trait __trait =
0424 _IsTriviallyAvailable<_Tp>::value ? _Trait::_TriviallyAvailable
0425 : _IsAvailable<_Tp>::value
0426 ? _Trait::_Available
0427 : _Trait::_Unavailable;
0428
0429 _LIBCPP_HIDE_FROM_ABI constexpr _Trait __common_trait(initializer_list<_Trait> __traits) {
0430 _Trait __result = _Trait::_TriviallyAvailable;
0431 for (_Trait __t : __traits) {
0432 if (static_cast<int>(__t) > static_cast<int>(__result)) {
0433 __result = __t;
0434 }
0435 }
0436 return __result;
0437 }
0438
0439 template <typename... _Types>
0440 struct __traits {
0441 static constexpr _Trait __copy_constructible_trait =
0442 __variant_detail::__common_trait({__trait<_Types, is_trivially_copy_constructible, is_copy_constructible>...});
0443
0444 static constexpr _Trait __move_constructible_trait =
0445 __variant_detail::__common_trait({__trait<_Types, is_trivially_move_constructible, is_move_constructible>...});
0446
0447 static constexpr _Trait __copy_assignable_trait = __variant_detail::__common_trait(
0448 {__copy_constructible_trait, __trait<_Types, is_trivially_copy_assignable, is_copy_assignable>...});
0449
0450 static constexpr _Trait __move_assignable_trait = __variant_detail::__common_trait(
0451 {__move_constructible_trait, __trait<_Types, is_trivially_move_assignable, is_move_assignable>...});
0452
0453 static constexpr _Trait __destructible_trait =
0454 __variant_detail::__common_trait({__trait<_Types, is_trivially_destructible, is_destructible>...});
0455 };
0456
0457 namespace __access {
0458
0459 struct __union {
0460 template <class _Vp>
0461 _LIBCPP_HIDE_FROM_ABI static constexpr auto&& __get_alt(_Vp&& __v, in_place_index_t<0>) {
0462 return std::forward<_Vp>(__v).__head;
0463 }
0464
0465 template <class _Vp, size_t _Ip>
0466 _LIBCPP_HIDE_FROM_ABI static constexpr auto&& __get_alt(_Vp&& __v, in_place_index_t<_Ip>) {
0467 return __get_alt(std::forward<_Vp>(__v).__tail, in_place_index<_Ip - 1>);
0468 }
0469 };
0470
0471 struct __base {
0472 template <size_t _Ip, class _Vp>
0473 _LIBCPP_HIDE_FROM_ABI static constexpr auto&& __get_alt(_Vp&& __v) {
0474 return __union::__get_alt(std::forward<_Vp>(__v).__data, in_place_index<_Ip>);
0475 }
0476 };
0477
0478 struct __variant {
0479 template <size_t _Ip, class _Vp>
0480 _LIBCPP_HIDE_FROM_ABI static constexpr auto&& __get_alt(_Vp&& __v) {
0481 return __base::__get_alt<_Ip>(std::forward<_Vp>(__v).__impl_);
0482 }
0483 };
0484
0485 } // namespace __access
0486
0487 namespace __visitation {
0488
0489 struct __base {
0490 template <class _Visitor, class... _Vs>
0491 _LIBCPP_HIDE_FROM_ABI static constexpr decltype(auto)
0492 __visit_alt_at(size_t __index, _Visitor&& __visitor, _Vs&&... __vs) {
0493 constexpr auto __fdiagonal = __make_fdiagonal<_Visitor&&, decltype(std::forward<_Vs>(__vs).__as_base())...>();
0494 return __fdiagonal[__index](std::forward<_Visitor>(__visitor), std::forward<_Vs>(__vs).__as_base()...);
0495 }
0496
0497 template <class _Visitor, class... _Vs>
0498 _LIBCPP_HIDE_FROM_ABI static constexpr decltype(auto) __visit_alt(_Visitor&& __visitor, _Vs&&... __vs) {
0499 constexpr auto __fmatrix = __make_fmatrix<_Visitor&&, decltype(std::forward<_Vs>(__vs).__as_base())...>();
0500 return __at(__fmatrix, __vs.index()...)(std::forward<_Visitor>(__visitor), std::forward<_Vs>(__vs).__as_base()...);
0501 }
0502
0503 private:
0504 template <class _Tp>
0505 _LIBCPP_HIDE_FROM_ABI static constexpr const _Tp& __at(const _Tp& __elem) {
0506 return __elem;
0507 }
0508
0509 template <class _Tp, size_t _Np, typename... _Indices>
0510 _LIBCPP_HIDE_FROM_ABI static constexpr auto&&
0511 __at(const __farray<_Tp, _Np>& __elems, size_t __index, _Indices... __indices) {
0512 return __at(__elems[__index], __indices...);
0513 }
0514
0515 template <class _Fp, class... _Fs>
0516 static _LIBCPP_HIDE_FROM_ABI constexpr void __std_visit_visitor_return_type_check() {
0517 static_assert(
0518 __all<is_same_v<_Fp, _Fs>...>::value, "`std::visit` requires the visitor to have a single return type.");
0519 }
0520
0521 template <class... _Fs>
0522 _LIBCPP_HIDE_FROM_ABI static constexpr auto __make_farray(_Fs&&... __fs) {
0523 __std_visit_visitor_return_type_check<__remove_cvref_t<_Fs>...>();
0524 using __result = __farray<common_type_t<__remove_cvref_t<_Fs>...>, sizeof...(_Fs)>;
0525 return __result{{std::forward<_Fs>(__fs)...}};
0526 }
0527
0528 template <size_t... _Is>
0529 struct __dispatcher {
0530 template <class _Fp, class... _Vs>
0531 _LIBCPP_HIDE_FROM_ABI static constexpr decltype(auto) __dispatch(_Fp __f, _Vs... __vs) {
0532 return std::__invoke(static_cast<_Fp>(__f), __access::__base::__get_alt<_Is>(static_cast<_Vs>(__vs))...);
0533 }
0534 };
0535
0536 template <class _Fp, class... _Vs, size_t... _Is>
0537 _LIBCPP_HIDE_FROM_ABI static constexpr auto __make_dispatch(index_sequence<_Is...>) {
0538 return __dispatcher<_Is...>::template __dispatch<_Fp, _Vs...>;
0539 }
0540
0541 template <size_t _Ip, class _Fp, class... _Vs>
0542 _LIBCPP_HIDE_FROM_ABI static constexpr auto __make_fdiagonal_impl() {
0543 return __make_dispatch<_Fp, _Vs...>(index_sequence<((void)__type_identity<_Vs>{}, _Ip)...>{});
0544 }
0545
0546 template <class _Fp, class... _Vs, size_t... _Is>
0547 _LIBCPP_HIDE_FROM_ABI static constexpr auto __make_fdiagonal_impl(index_sequence<_Is...>) {
0548 return __base::__make_farray(__make_fdiagonal_impl<_Is, _Fp, _Vs...>()...);
0549 }
0550
0551 template <class _Fp, class _Vp, class... _Vs>
0552 _LIBCPP_HIDE_FROM_ABI static constexpr auto __make_fdiagonal() {
0553 constexpr size_t __np = __remove_cvref_t<_Vp>::__size();
0554 static_assert(__all<(__np == __remove_cvref_t<_Vs>::__size())...>::value);
0555 return __make_fdiagonal_impl<_Fp, _Vp, _Vs...>(make_index_sequence<__np>{});
0556 }
0557
0558 template <class _Fp, class... _Vs, size_t... _Is>
0559 _LIBCPP_HIDE_FROM_ABI static constexpr auto __make_fmatrix_impl(index_sequence<_Is...> __is) {
0560 return __make_dispatch<_Fp, _Vs...>(__is);
0561 }
0562
0563 template <class _Fp, class... _Vs, size_t... _Is, size_t... _Js, class... _Ls>
0564 _LIBCPP_HIDE_FROM_ABI static constexpr auto
0565 __make_fmatrix_impl(index_sequence<_Is...>, index_sequence<_Js...>, _Ls... __ls) {
0566 return __base::__make_farray(__make_fmatrix_impl<_Fp, _Vs...>(index_sequence<_Is..., _Js>{}, __ls...)...);
0567 }
0568
0569 template <class _Fp, class... _Vs>
0570 _LIBCPP_HIDE_FROM_ABI static constexpr auto __make_fmatrix() {
0571 return __make_fmatrix_impl<_Fp, _Vs...>(
0572 index_sequence<>{}, make_index_sequence<__remove_cvref_t<_Vs>::__size()>{}...);
0573 }
0574 };
0575
0576 struct __variant {
0577 template <class _Visitor, class... _Vs>
0578 _LIBCPP_HIDE_FROM_ABI static constexpr decltype(auto)
0579 __visit_alt_at(size_t __index, _Visitor&& __visitor, _Vs&&... __vs) {
0580 return __base::__visit_alt_at(__index, std::forward<_Visitor>(__visitor), std::forward<_Vs>(__vs).__impl_...);
0581 }
0582
0583 template <class _Visitor, class... _Vs>
0584 _LIBCPP_HIDE_FROM_ABI static constexpr decltype(auto) __visit_alt(_Visitor&& __visitor, _Vs&&... __vs) {
0585 return __base::__visit_alt(
0586 std::forward<_Visitor>(__visitor), std::__as_variant(std::forward<_Vs>(__vs)).__impl_...);
0587 }
0588
0589 template <class _Visitor, class... _Vs>
0590 _LIBCPP_HIDE_FROM_ABI static constexpr decltype(auto)
0591 __visit_value_at(size_t __index, _Visitor&& __visitor, _Vs&&... __vs) {
0592 return __visit_alt_at(__index, __make_value_visitor(std::forward<_Visitor>(__visitor)), std::forward<_Vs>(__vs)...);
0593 }
0594
0595 template <class _Visitor, class... _Vs>
0596 _LIBCPP_HIDE_FROM_ABI static constexpr decltype(auto) __visit_value(_Visitor&& __visitor, _Vs&&... __vs) {
0597 return __visit_alt(__make_value_visitor(std::forward<_Visitor>(__visitor)), std::forward<_Vs>(__vs)...);
0598 }
0599
0600 # if _LIBCPP_STD_VER >= 20
0601 template <class _Rp, class _Visitor, class... _Vs>
0602 _LIBCPP_HIDE_FROM_ABI static constexpr _Rp __visit_value(_Visitor&& __visitor, _Vs&&... __vs) {
0603 return __visit_alt(__make_value_visitor<_Rp>(std::forward<_Visitor>(__visitor)), std::forward<_Vs>(__vs)...);
0604 }
0605 # endif
0606
0607 private:
0608 template <class _Visitor, class... _Values>
0609 static _LIBCPP_HIDE_FROM_ABI constexpr void __std_visit_exhaustive_visitor_check() {
0610 static_assert(is_invocable_v<_Visitor, _Values...>, "`std::visit` requires the visitor to be exhaustive.");
0611 }
0612
0613 template <class _Visitor>
0614 struct __value_visitor {
0615 template <class... _Alts>
0616 _LIBCPP_HIDE_FROM_ABI constexpr decltype(auto) operator()(_Alts&&... __alts) const {
0617 __std_visit_exhaustive_visitor_check< _Visitor, decltype((std::forward<_Alts>(__alts).__value))...>();
0618 return std::__invoke(std::forward<_Visitor>(__visitor), std::forward<_Alts>(__alts).__value...);
0619 }
0620 _Visitor&& __visitor;
0621 };
0622
0623 # if _LIBCPP_STD_VER >= 20
0624 template <class _Rp, class _Visitor>
0625 struct __value_visitor_return_type {
0626 template <class... _Alts>
0627 _LIBCPP_HIDE_FROM_ABI constexpr _Rp operator()(_Alts&&... __alts) const {
0628 __std_visit_exhaustive_visitor_check< _Visitor, decltype((std::forward<_Alts>(__alts).__value))...>();
0629 if constexpr (is_void_v<_Rp>) {
0630 std::__invoke(std::forward<_Visitor>(__visitor), std::forward<_Alts>(__alts).__value...);
0631 } else {
0632 return std::__invoke(std::forward<_Visitor>(__visitor), std::forward<_Alts>(__alts).__value...);
0633 }
0634 }
0635
0636 _Visitor&& __visitor;
0637 };
0638 # endif
0639
0640 template <class _Visitor>
0641 _LIBCPP_HIDE_FROM_ABI static constexpr auto __make_value_visitor(_Visitor&& __visitor) {
0642 return __value_visitor<_Visitor>{std::forward<_Visitor>(__visitor)};
0643 }
0644
0645 # if _LIBCPP_STD_VER >= 20
0646 template <class _Rp, class _Visitor>
0647 _LIBCPP_HIDE_FROM_ABI static constexpr auto __make_value_visitor(_Visitor&& __visitor) {
0648 return __value_visitor_return_type<_Rp, _Visitor>{std::forward<_Visitor>(__visitor)};
0649 }
0650 # endif
0651 };
0652
0653 } // namespace __visitation
0654
0655 // Adding semi-colons in macro expansions helps clang-format to do a better job.
0656 // This macro is used to avoid compilation errors due to "stray" semi-colons.
0657 # define _LIBCPP_EAT_SEMICOLON static_assert(true, "")
0658
0659 template <size_t _Index, class _Tp>
0660 struct _LIBCPP_TEMPLATE_VIS __alt {
0661 using __value_type _LIBCPP_NODEBUG = _Tp;
0662 static constexpr size_t __index = _Index;
0663
0664 template <class... _Args>
0665 _LIBCPP_HIDE_FROM_ABI explicit constexpr __alt(in_place_t, _Args&&... __args)
0666 : __value(std::forward<_Args>(__args)...) {}
0667
0668 __value_type __value;
0669 };
0670
0671 template <_Trait _DestructibleTrait, size_t _Index, class... _Types>
0672 union _LIBCPP_TEMPLATE_VIS __union;
0673
0674 template <_Trait _DestructibleTrait, size_t _Index>
0675 union _LIBCPP_TEMPLATE_VIS __union<_DestructibleTrait, _Index> {};
0676
0677 # define _LIBCPP_VARIANT_UNION(destructible_trait, destructor_definition) \
0678 template <size_t _Index, class _Tp, class... _Types> \
0679 union _LIBCPP_TEMPLATE_VIS __union<destructible_trait, _Index, _Tp, _Types...> { \
0680 public: \
0681 _LIBCPP_HIDE_FROM_ABI explicit constexpr __union(__valueless_t) noexcept : __dummy{} {} \
0682 \
0683 template <class... _Args> \
0684 _LIBCPP_HIDE_FROM_ABI explicit constexpr __union(in_place_index_t<0>, _Args&&... __args) \
0685 : __head(in_place, std::forward<_Args>(__args)...) {} \
0686 \
0687 template <size_t _Ip, class... _Args> \
0688 _LIBCPP_HIDE_FROM_ABI explicit constexpr __union(in_place_index_t<_Ip>, _Args&&... __args) \
0689 : __tail(in_place_index<_Ip - 1>, std::forward<_Args>(__args)...) {} \
0690 \
0691 _LIBCPP_HIDE_FROM_ABI __union(const __union&) = default; \
0692 _LIBCPP_HIDE_FROM_ABI __union(__union&&) = default; \
0693 _LIBCPP_HIDE_FROM_ABI __union& operator=(const __union&) = default; \
0694 _LIBCPP_HIDE_FROM_ABI __union& operator=(__union&&) = default; \
0695 destructor_definition; \
0696 \
0697 private: \
0698 char __dummy; \
0699 __alt<_Index, _Tp> __head; \
0700 __union<destructible_trait, _Index + 1, _Types...> __tail; \
0701 \
0702 friend struct __access::__union; \
0703 }
0704
0705 _LIBCPP_VARIANT_UNION(_Trait::_TriviallyAvailable,
0706 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 ~__union() = default);
0707 _LIBCPP_VARIANT_UNION(
0708 _Trait::_Available, _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 ~__union() {} _LIBCPP_EAT_SEMICOLON);
0709 _LIBCPP_VARIANT_UNION(_Trait::_Unavailable, _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 ~__union() = delete);
0710
0711 # undef _LIBCPP_VARIANT_UNION
0712
0713 template <_Trait _DestructibleTrait, class... _Types>
0714 class _LIBCPP_TEMPLATE_VIS __base {
0715 public:
0716 using __index_t _LIBCPP_NODEBUG = __variant_index_t<sizeof...(_Types)>;
0717
0718 _LIBCPP_HIDE_FROM_ABI explicit constexpr __base(__valueless_t __tag) noexcept
0719 : __data(__tag), __index(__variant_npos<__index_t>) {}
0720
0721 template <size_t _Ip, class... _Args>
0722 _LIBCPP_HIDE_FROM_ABI explicit constexpr __base(in_place_index_t<_Ip>, _Args&&... __args)
0723 : __data(in_place_index<_Ip>, std::forward<_Args>(__args)...), __index(_Ip) {}
0724
0725 _LIBCPP_HIDE_FROM_ABI constexpr bool valueless_by_exception() const noexcept { return index() == variant_npos; }
0726
0727 _LIBCPP_HIDE_FROM_ABI constexpr size_t index() const noexcept {
0728 return __index == __variant_npos<__index_t> ? variant_npos : __index;
0729 }
0730
0731 protected:
0732 _LIBCPP_HIDE_FROM_ABI constexpr auto&& __as_base() & { return *this; }
0733
0734 _LIBCPP_HIDE_FROM_ABI constexpr auto&& __as_base() && { return std::move(*this); }
0735
0736 _LIBCPP_HIDE_FROM_ABI constexpr auto&& __as_base() const& { return *this; }
0737
0738 _LIBCPP_HIDE_FROM_ABI constexpr auto&& __as_base() const&& { return std::move(*this); }
0739
0740 _LIBCPP_HIDE_FROM_ABI static constexpr size_t __size() { return sizeof...(_Types); }
0741
0742 __union<_DestructibleTrait, 0, _Types...> __data;
0743 __index_t __index;
0744
0745 friend struct __access::__base;
0746 friend struct __visitation::__base;
0747 };
0748
0749 template <class _Traits, _Trait = _Traits::__destructible_trait>
0750 class _LIBCPP_TEMPLATE_VIS __dtor;
0751
0752 # define _LIBCPP_VARIANT_DESTRUCTOR(destructible_trait, destructor_definition, destroy) \
0753 template <class... _Types> \
0754 class _LIBCPP_TEMPLATE_VIS __dtor<__traits<_Types...>, destructible_trait> \
0755 : public __base<destructible_trait, _Types...> { \
0756 using __base_type _LIBCPP_NODEBUG = __base<destructible_trait, _Types...>; \
0757 using __index_t _LIBCPP_NODEBUG = typename __base_type::__index_t; \
0758 \
0759 public: \
0760 using __base_type::__base_type; \
0761 using __base_type::operator=; \
0762 _LIBCPP_HIDE_FROM_ABI __dtor(const __dtor&) = default; \
0763 _LIBCPP_HIDE_FROM_ABI __dtor(__dtor&&) = default; \
0764 _LIBCPP_HIDE_FROM_ABI __dtor& operator=(const __dtor&) = default; \
0765 _LIBCPP_HIDE_FROM_ABI __dtor& operator=(__dtor&&) = default; \
0766 destructor_definition; \
0767 \
0768 protected: \
0769 destroy; \
0770 }
0771
0772 _LIBCPP_VARIANT_DESTRUCTOR(
0773 _Trait::_TriviallyAvailable,
0774 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 ~__dtor() = default,
0775 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __destroy() noexcept {
0776 this->__index = __variant_npos<__index_t>;
0777 } _LIBCPP_EAT_SEMICOLON);
0778
0779 _LIBCPP_VARIANT_DESTRUCTOR(
0780 _Trait::_Available,
0781 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 ~__dtor() { __destroy(); } _LIBCPP_EAT_SEMICOLON,
0782 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __destroy() noexcept {
0783 if (!this->valueless_by_exception()) {
0784 __visitation::__base::__visit_alt(
0785 [](auto& __alt) noexcept {
0786 using __alt_type = __remove_cvref_t<decltype(__alt)>;
0787 __alt.~__alt_type();
0788 },
0789 *this);
0790 }
0791 this->__index = __variant_npos<__index_t>;
0792 } _LIBCPP_EAT_SEMICOLON);
0793
0794 _LIBCPP_VARIANT_DESTRUCTOR(_Trait::_Unavailable,
0795 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 ~__dtor() = delete,
0796 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __destroy() noexcept = delete);
0797
0798 # undef _LIBCPP_VARIANT_DESTRUCTOR
0799
0800 template <class _Traits>
0801 class _LIBCPP_TEMPLATE_VIS __ctor : public __dtor<_Traits> {
0802 using __base_type _LIBCPP_NODEBUG = __dtor<_Traits>;
0803
0804 public:
0805 using __base_type::__base_type;
0806 using __base_type::operator=;
0807
0808 protected:
0809 template <class _Rhs>
0810 _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR_SINCE_CXX20 void __generic_construct(__ctor& __lhs, _Rhs&& __rhs) {
0811 __lhs.__destroy();
0812 if (!__rhs.valueless_by_exception()) {
0813 auto __rhs_index = __rhs.index();
0814 __visitation::__base::__visit_alt_at(
0815 __rhs_index,
0816 [&__lhs](auto&& __rhs_alt) {
0817 std::__construct_at(std::addressof(__lhs.__data),
0818 in_place_index<__decay_t<decltype(__rhs_alt)>::__index>,
0819 std::forward<decltype(__rhs_alt)>(__rhs_alt).__value);
0820 },
0821 std::forward<_Rhs>(__rhs));
0822 __lhs.__index = __rhs_index;
0823 }
0824 }
0825 };
0826
0827 template <class _Traits, _Trait = _Traits::__move_constructible_trait>
0828 class _LIBCPP_TEMPLATE_VIS __move_constructor;
0829
0830 # define _LIBCPP_VARIANT_MOVE_CONSTRUCTOR(move_constructible_trait, move_constructor_definition) \
0831 template <class... _Types> \
0832 class _LIBCPP_TEMPLATE_VIS __move_constructor<__traits<_Types...>, move_constructible_trait> \
0833 : public __ctor<__traits<_Types...>> { \
0834 using __base_type _LIBCPP_NODEBUG = __ctor<__traits<_Types...>>; \
0835 \
0836 public: \
0837 using __base_type::__base_type; \
0838 using __base_type::operator=; \
0839 \
0840 _LIBCPP_HIDE_FROM_ABI __move_constructor(const __move_constructor&) = default; \
0841 _LIBCPP_HIDE_FROM_ABI ~__move_constructor() = default; \
0842 _LIBCPP_HIDE_FROM_ABI __move_constructor& operator=(const __move_constructor&) = default; \
0843 _LIBCPP_HIDE_FROM_ABI __move_constructor& operator=(__move_constructor&&) = default; \
0844 move_constructor_definition; \
0845 }
0846
0847 _LIBCPP_VARIANT_MOVE_CONSTRUCTOR(
0848 _Trait::_TriviallyAvailable,
0849 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __move_constructor(__move_constructor&& __that) = default);
0850
0851 _LIBCPP_VARIANT_MOVE_CONSTRUCTOR(
0852 _Trait::_Available,
0853 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __move_constructor(__move_constructor&& __that) noexcept(
0854 __all<is_nothrow_move_constructible_v<_Types>...>::value)
0855 : __move_constructor(__valueless_t{}) {
0856 this->__generic_construct(*this, std::move(__that));
0857 } _LIBCPP_EAT_SEMICOLON);
0858
0859 _LIBCPP_VARIANT_MOVE_CONSTRUCTOR(
0860 _Trait::_Unavailable,
0861 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __move_constructor(__move_constructor&&) = delete);
0862
0863 # undef _LIBCPP_VARIANT_MOVE_CONSTRUCTOR
0864
0865 template <class _Traits, _Trait = _Traits::__copy_constructible_trait>
0866 class _LIBCPP_TEMPLATE_VIS __copy_constructor;
0867
0868 # define _LIBCPP_VARIANT_COPY_CONSTRUCTOR(copy_constructible_trait, copy_constructor_definition) \
0869 template <class... _Types> \
0870 class _LIBCPP_TEMPLATE_VIS __copy_constructor<__traits<_Types...>, copy_constructible_trait> \
0871 : public __move_constructor<__traits<_Types...>> { \
0872 using __base_type _LIBCPP_NODEBUG = __move_constructor<__traits<_Types...>>; \
0873 \
0874 public: \
0875 using __base_type::__base_type; \
0876 using __base_type::operator=; \
0877 \
0878 _LIBCPP_HIDE_FROM_ABI __copy_constructor(__copy_constructor&&) = default; \
0879 _LIBCPP_HIDE_FROM_ABI ~__copy_constructor() = default; \
0880 _LIBCPP_HIDE_FROM_ABI __copy_constructor& operator=(const __copy_constructor&) = default; \
0881 _LIBCPP_HIDE_FROM_ABI __copy_constructor& operator=(__copy_constructor&&) = default; \
0882 copy_constructor_definition; \
0883 }
0884
0885 _LIBCPP_VARIANT_COPY_CONSTRUCTOR(
0886 _Trait::_TriviallyAvailable,
0887 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __copy_constructor(const __copy_constructor& __that) = default);
0888
0889 _LIBCPP_VARIANT_COPY_CONSTRUCTOR(
0890 _Trait::_Available,
0891 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __copy_constructor(const __copy_constructor& __that)
0892 : __copy_constructor(__valueless_t{}) { this->__generic_construct(*this, __that); } _LIBCPP_EAT_SEMICOLON);
0893
0894 _LIBCPP_VARIANT_COPY_CONSTRUCTOR(
0895 _Trait::_Unavailable,
0896 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __copy_constructor(const __copy_constructor&) = delete);
0897
0898 # undef _LIBCPP_VARIANT_COPY_CONSTRUCTOR
0899
0900 template <class _Traits>
0901 class _LIBCPP_TEMPLATE_VIS __assignment : public __copy_constructor<_Traits> {
0902 using __base_type _LIBCPP_NODEBUG = __copy_constructor<_Traits>;
0903
0904 public:
0905 using __base_type::__base_type;
0906 using __base_type::operator=;
0907
0908 template <size_t _Ip, class... _Args>
0909 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 auto& __emplace(_Args&&... __args) {
0910 this->__destroy();
0911 std::__construct_at(std::addressof(this->__data), in_place_index<_Ip>, std::forward<_Args>(__args)...);
0912 this->__index = _Ip;
0913 return __access::__base::__get_alt<_Ip>(*this).__value;
0914 }
0915
0916 protected:
0917 template <size_t _Ip, class _Tp, class _Arg>
0918 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __assign_alt(__alt<_Ip, _Tp>& __a, _Arg&& __arg) {
0919 if (this->index() == _Ip) {
0920 __a.__value = std::forward<_Arg>(__arg);
0921 } else {
0922 struct {
0923 _LIBCPP_HIDDEN _LIBCPP_CONSTEXPR_SINCE_CXX20 void operator()(true_type) const {
0924 __this->__emplace<_Ip>(std::forward<_Arg>(__arg));
0925 }
0926 _LIBCPP_HIDDEN _LIBCPP_CONSTEXPR_SINCE_CXX20 void operator()(false_type) const {
0927 __this->__emplace<_Ip>(_Tp(std::forward<_Arg>(__arg)));
0928 }
0929 __assignment* __this;
0930 _Arg&& __arg;
0931 } __impl{this, std::forward<_Arg>(__arg)};
0932 __impl(bool_constant < is_nothrow_constructible_v<_Tp, _Arg> || !is_nothrow_move_constructible_v < _Tp >> {});
0933 }
0934 }
0935
0936 template <class _That>
0937 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __generic_assign(_That&& __that) {
0938 if (this->valueless_by_exception() && __that.valueless_by_exception()) {
0939 // do nothing.
0940 } else if (__that.valueless_by_exception()) {
0941 this->__destroy();
0942 } else {
0943 __visitation::__base::__visit_alt_at(
0944 __that.index(),
0945 [this](auto& __this_alt, auto&& __that_alt) {
0946 this->__assign_alt(__this_alt, std::forward<decltype(__that_alt)>(__that_alt).__value);
0947 },
0948 *this,
0949 std::forward<_That>(__that));
0950 }
0951 }
0952 };
0953
0954 template <class _Traits, _Trait = _Traits::__move_assignable_trait>
0955 class _LIBCPP_TEMPLATE_VIS __move_assignment;
0956
0957 # define _LIBCPP_VARIANT_MOVE_ASSIGNMENT(move_assignable_trait, move_assignment_definition) \
0958 template <class... _Types> \
0959 class _LIBCPP_TEMPLATE_VIS __move_assignment<__traits<_Types...>, move_assignable_trait> \
0960 : public __assignment<__traits<_Types...>> { \
0961 using __base_type _LIBCPP_NODEBUG = __assignment<__traits<_Types...>>; \
0962 \
0963 public: \
0964 using __base_type::__base_type; \
0965 using __base_type::operator=; \
0966 \
0967 _LIBCPP_HIDE_FROM_ABI __move_assignment(const __move_assignment&) = default; \
0968 _LIBCPP_HIDE_FROM_ABI __move_assignment(__move_assignment&&) = default; \
0969 _LIBCPP_HIDE_FROM_ABI ~__move_assignment() = default; \
0970 _LIBCPP_HIDE_FROM_ABI __move_assignment& operator=(const __move_assignment&) = default; \
0971 move_assignment_definition; \
0972 }
0973
0974 _LIBCPP_VARIANT_MOVE_ASSIGNMENT(_Trait::_TriviallyAvailable,
0975 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __move_assignment& operator=(
0976 __move_assignment&& __that) = default);
0977
0978 _LIBCPP_VARIANT_MOVE_ASSIGNMENT(
0979 _Trait::_Available,
0980 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __move_assignment&
0981 operator=(__move_assignment&& __that) noexcept(
0982 __all<(is_nothrow_move_constructible_v<_Types> && is_nothrow_move_assignable_v<_Types>)...>::value) {
0983 this->__generic_assign(std::move(__that));
0984 return *this;
0985 } _LIBCPP_EAT_SEMICOLON);
0986
0987 _LIBCPP_VARIANT_MOVE_ASSIGNMENT(
0988 _Trait::_Unavailable,
0989 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __move_assignment& operator=(__move_assignment&&) = delete);
0990
0991 # undef _LIBCPP_VARIANT_MOVE_ASSIGNMENT
0992
0993 template <class _Traits, _Trait = _Traits::__copy_assignable_trait>
0994 class _LIBCPP_TEMPLATE_VIS __copy_assignment;
0995
0996 # define _LIBCPP_VARIANT_COPY_ASSIGNMENT(copy_assignable_trait, copy_assignment_definition) \
0997 template <class... _Types> \
0998 class _LIBCPP_TEMPLATE_VIS __copy_assignment<__traits<_Types...>, copy_assignable_trait> \
0999 : public __move_assignment<__traits<_Types...>> { \
1000 using __base_type _LIBCPP_NODEBUG = __move_assignment<__traits<_Types...>>; \
1001 \
1002 public: \
1003 using __base_type::__base_type; \
1004 using __base_type::operator=; \
1005 \
1006 _LIBCPP_HIDE_FROM_ABI __copy_assignment(const __copy_assignment&) = default; \
1007 _LIBCPP_HIDE_FROM_ABI __copy_assignment(__copy_assignment&&) = default; \
1008 _LIBCPP_HIDE_FROM_ABI ~__copy_assignment() = default; \
1009 _LIBCPP_HIDE_FROM_ABI __copy_assignment& operator=(__copy_assignment&&) = default; \
1010 copy_assignment_definition; \
1011 }
1012
1013 _LIBCPP_VARIANT_COPY_ASSIGNMENT(_Trait::_TriviallyAvailable,
1014 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __copy_assignment& operator=(
1015 const __copy_assignment& __that) = default);
1016
1017 _LIBCPP_VARIANT_COPY_ASSIGNMENT(
1018 _Trait::_Available,
1019 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __copy_assignment&
1020 operator=(const __copy_assignment& __that) {
1021 this->__generic_assign(__that);
1022 return *this;
1023 } _LIBCPP_EAT_SEMICOLON);
1024
1025 _LIBCPP_VARIANT_COPY_ASSIGNMENT(_Trait::_Unavailable,
1026 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __copy_assignment& operator=(
1027 const __copy_assignment&) = delete);
1028
1029 # undef _LIBCPP_VARIANT_COPY_ASSIGNMENT
1030
1031 template <class... _Types>
1032 class _LIBCPP_TEMPLATE_VIS __impl : public __copy_assignment<__traits<_Types...>> {
1033 using __base_type _LIBCPP_NODEBUG = __copy_assignment<__traits<_Types...>>;
1034
1035 public:
1036 using __base_type::__base_type; // get in_place_index_t constructor & friends
1037 _LIBCPP_HIDE_FROM_ABI __impl(__impl const&) = default;
1038 _LIBCPP_HIDE_FROM_ABI __impl(__impl&&) = default;
1039 _LIBCPP_HIDE_FROM_ABI __impl& operator=(__impl const&) = default;
1040 _LIBCPP_HIDE_FROM_ABI __impl& operator=(__impl&&) = default;
1041
1042 template <size_t _Ip, class _Arg>
1043 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __assign(_Arg&& __arg) {
1044 this->__assign_alt(__access::__base::__get_alt<_Ip>(*this), std::forward<_Arg>(__arg));
1045 }
1046
1047 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __swap(__impl& __that) {
1048 if (this->valueless_by_exception() && __that.valueless_by_exception()) {
1049 // do nothing.
1050 } else if (this->index() == __that.index()) {
1051 __visitation::__base::__visit_alt_at(
1052 this->index(),
1053 [](auto& __this_alt, auto& __that_alt) {
1054 using std::swap;
1055 swap(__this_alt.__value, __that_alt.__value);
1056 },
1057 *this,
1058 __that);
1059 } else {
1060 __impl* __lhs = this;
1061 __impl* __rhs = std::addressof(__that);
1062 if (__lhs->__move_nothrow() && !__rhs->__move_nothrow()) {
1063 std::swap(__lhs, __rhs);
1064 }
1065 __impl __tmp(std::move(*__rhs));
1066 # if _LIBCPP_HAS_EXCEPTIONS
1067 if constexpr (__all<is_nothrow_move_constructible_v<_Types>...>::value) {
1068 this->__generic_construct(*__rhs, std::move(*__lhs));
1069 } else {
1070 // EXTENSION: When the move construction of `__lhs` into `__rhs` throws
1071 // and `__tmp` is nothrow move constructible then we move `__tmp` back
1072 // into `__rhs` and provide the strong exception safety guarantee.
1073 try {
1074 this->__generic_construct(*__rhs, std::move(*__lhs));
1075 } catch (...) {
1076 if (__tmp.__move_nothrow()) {
1077 this->__generic_construct(*__rhs, std::move(__tmp));
1078 }
1079 throw;
1080 }
1081 }
1082 # else
1083 // this isn't consolidated with the `if constexpr` branch above due to
1084 // `throw` being ill-formed with exceptions disabled even when discarded.
1085 this->__generic_construct(*__rhs, std::move(*__lhs));
1086 # endif
1087 this->__generic_construct(*__lhs, std::move(__tmp));
1088 }
1089 }
1090
1091 private:
1092 constexpr inline _LIBCPP_HIDE_FROM_ABI bool __move_nothrow() const {
1093 constexpr bool __results[] = {is_nothrow_move_constructible_v<_Types>...};
1094 return this->valueless_by_exception() || __results[this->index()];
1095 }
1096 };
1097
1098 struct __no_narrowing_check {
1099 template <class _Dest, class _Source>
1100 using _Apply _LIBCPP_NODEBUG = __type_identity<_Dest>;
1101 };
1102
1103 struct __narrowing_check {
1104 template <class _Dest>
1105 static auto __test_impl(_Dest (&&)[1]) -> __type_identity<_Dest>;
1106 template <class _Dest, class _Source>
1107 using _Apply _LIBCPP_NODEBUG = decltype(__test_impl<_Dest>({std::declval<_Source>()}));
1108 };
1109
1110 template <class _Dest, class _Source>
1111 using __check_for_narrowing _LIBCPP_NODEBUG =
1112 typename _If< is_arithmetic<_Dest>::value, __narrowing_check, __no_narrowing_check >::template _Apply<_Dest,
1113 _Source>;
1114
1115 template <class _Tp, size_t _Idx>
1116 struct __overload {
1117 template <class _Up>
1118 auto operator()(_Tp, _Up&&) const -> __check_for_narrowing<_Tp, _Up>;
1119 };
1120
1121 template <class... _Bases>
1122 struct __all_overloads : _Bases... {
1123 void operator()() const;
1124 using _Bases::operator()...;
1125 };
1126
1127 template <class _IdxSeq>
1128 struct __make_overloads_imp;
1129
1130 template <size_t... _Idx>
1131 struct __make_overloads_imp<__tuple_indices<_Idx...> > {
1132 template <class... _Types>
1133 using _Apply _LIBCPP_NODEBUG = __all_overloads<__overload<_Types, _Idx>...>;
1134 };
1135
1136 template <class... _Types>
1137 using _MakeOverloads _LIBCPP_NODEBUG =
1138 typename __make_overloads_imp< __make_indices_imp<sizeof...(_Types), 0> >::template _Apply<_Types...>;
1139
1140 template <class _Tp, class... _Types>
1141 using __best_match_t _LIBCPP_NODEBUG = typename invoke_result_t<_MakeOverloads<_Types...>, _Tp, _Tp>::type;
1142
1143 } // namespace __variant_detail
1144
1145 template <class _Visitor, class... _Vs, typename = void_t<decltype(std::__as_variant(std::declval<_Vs>()))...>>
1146 _LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS constexpr decltype(auto)
1147 visit(_Visitor&& __visitor, _Vs&&... __vs);
1148
1149 # if _LIBCPP_STD_VER >= 20
1150 template <class _Rp,
1151 class _Visitor,
1152 class... _Vs,
1153 typename = void_t<decltype(std::__as_variant(std::declval<_Vs>()))...>>
1154 _LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS constexpr _Rp
1155 visit(_Visitor&& __visitor, _Vs&&... __vs);
1156 # endif
1157
1158 template <class... _Types>
1159 class _LIBCPP_TEMPLATE_VIS _LIBCPP_DECLSPEC_EMPTY_BASES _LIBCPP_NO_SPECIALIZATIONS variant
1160 : private __sfinae_ctor_base< __all<is_copy_constructible_v<_Types>...>::value,
1161 __all<is_move_constructible_v<_Types>...>::value>,
1162 private __sfinae_assign_base<
1163 __all<(is_copy_constructible_v<_Types> && is_copy_assignable_v<_Types>)...>::value,
1164 __all<(is_move_constructible_v<_Types> && is_move_assignable_v<_Types>)...>::value> {
1165 static_assert(0 < sizeof...(_Types), "variant must consist of at least one alternative.");
1166
1167 static_assert(__all<!is_array_v<_Types>...>::value, "variant can not have an array type as an alternative.");
1168
1169 static_assert(__all<!is_reference_v<_Types>...>::value, "variant can not have a reference type as an alternative.");
1170
1171 static_assert(__all<!is_void_v<_Types>...>::value, "variant can not have a void type as an alternative.");
1172
1173 using __first_type _LIBCPP_NODEBUG = variant_alternative_t<0, variant>;
1174
1175 public:
1176 using __trivially_relocatable _LIBCPP_NODEBUG =
1177 conditional_t<_And<__libcpp_is_trivially_relocatable<_Types>...>::value, variant, void>;
1178
1179 template <bool _Dummy = true,
1180 enable_if_t<__dependent_type<is_default_constructible<__first_type>, _Dummy>::value, int> = 0>
1181 _LIBCPP_HIDE_FROM_ABI constexpr variant() noexcept(is_nothrow_default_constructible_v<__first_type>)
1182 : __impl_(in_place_index<0>) {}
1183
1184 _LIBCPP_HIDE_FROM_ABI constexpr variant(const variant&) = default;
1185 _LIBCPP_HIDE_FROM_ABI constexpr variant(variant&&) = default;
1186
1187 template < class _Arg,
1188 enable_if_t<!is_same_v<__remove_cvref_t<_Arg>, variant>, int> = 0,
1189 enable_if_t<!__is_inplace_type<__remove_cvref_t<_Arg>>::value, int> = 0,
1190 enable_if_t<!__is_inplace_index<__remove_cvref_t<_Arg>>::value, int> = 0,
1191 class _Tp = __variant_detail::__best_match_t<_Arg, _Types...>,
1192 size_t _Ip = __find_detail::__find_unambiguous_index_sfinae<_Tp, _Types...>::value,
1193 enable_if_t<is_constructible_v<_Tp, _Arg>, int> = 0>
1194 _LIBCPP_HIDE_FROM_ABI constexpr variant(_Arg&& __arg) noexcept(is_nothrow_constructible_v<_Tp, _Arg>)
1195 : __impl_(in_place_index<_Ip>, std::forward<_Arg>(__arg)) {}
1196
1197 template <size_t _Ip,
1198 class... _Args,
1199 class = enable_if_t<(_Ip < sizeof...(_Types)), int>,
1200 class _Tp = variant_alternative_t<_Ip, variant<_Types...>>,
1201 enable_if_t<is_constructible_v<_Tp, _Args...>, int> = 0>
1202 _LIBCPP_HIDE_FROM_ABI explicit constexpr variant(in_place_index_t<_Ip>, _Args&&... __args) noexcept(
1203 is_nothrow_constructible_v<_Tp, _Args...>)
1204 : __impl_(in_place_index<_Ip>, std::forward<_Args>(__args)...) {}
1205
1206 template < size_t _Ip,
1207 class _Up,
1208 class... _Args,
1209 enable_if_t<(_Ip < sizeof...(_Types)), int> = 0,
1210 class _Tp = variant_alternative_t<_Ip, variant<_Types...>>,
1211 enable_if_t<is_constructible_v<_Tp, initializer_list<_Up>&, _Args...>, int> = 0>
1212 _LIBCPP_HIDE_FROM_ABI explicit constexpr variant(
1213 in_place_index_t<_Ip>,
1214 initializer_list<_Up> __il,
1215 _Args&&... __args) noexcept(is_nothrow_constructible_v<_Tp, initializer_list<_Up>&, _Args...>)
1216 : __impl_(in_place_index<_Ip>, __il, std::forward<_Args>(__args)...) {}
1217
1218 template < class _Tp,
1219 class... _Args,
1220 size_t _Ip = __find_detail::__find_unambiguous_index_sfinae<_Tp, _Types...>::value,
1221 enable_if_t<is_constructible_v<_Tp, _Args...>, int> = 0>
1222 _LIBCPP_HIDE_FROM_ABI explicit constexpr variant(in_place_type_t<_Tp>, _Args&&... __args) noexcept(
1223 is_nothrow_constructible_v<_Tp, _Args...>)
1224 : __impl_(in_place_index<_Ip>, std::forward<_Args>(__args)...) {}
1225
1226 template < class _Tp,
1227 class _Up,
1228 class... _Args,
1229 size_t _Ip = __find_detail::__find_unambiguous_index_sfinae<_Tp, _Types...>::value,
1230 enable_if_t<is_constructible_v<_Tp, initializer_list<_Up>&, _Args...>, int> = 0>
1231 _LIBCPP_HIDE_FROM_ABI explicit constexpr variant(
1232 in_place_type_t<_Tp>,
1233 initializer_list<_Up> __il,
1234 _Args&&... __args) noexcept(is_nothrow_constructible_v<_Tp, initializer_list< _Up>&, _Args...>)
1235 : __impl_(in_place_index<_Ip>, __il, std::forward<_Args>(__args)...) {}
1236
1237 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 ~variant() = default;
1238
1239 _LIBCPP_HIDE_FROM_ABI constexpr variant& operator=(const variant&) = default;
1240 _LIBCPP_HIDE_FROM_ABI constexpr variant& operator=(variant&&) = default;
1241
1242 template < class _Arg,
1243 enable_if_t<!is_same_v<__remove_cvref_t<_Arg>, variant>, int> = 0,
1244 class _Tp = __variant_detail::__best_match_t<_Arg, _Types...>,
1245 size_t _Ip = __find_detail::__find_unambiguous_index_sfinae<_Tp, _Types...>::value,
1246 enable_if_t<is_assignable_v<_Tp&, _Arg> && is_constructible_v<_Tp, _Arg>, int> = 0>
1247 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 variant&
1248 operator=(_Arg&& __arg) noexcept(is_nothrow_assignable_v<_Tp&, _Arg> && is_nothrow_constructible_v<_Tp, _Arg>) {
1249 __impl_.template __assign<_Ip>(std::forward<_Arg>(__arg));
1250 return *this;
1251 }
1252
1253 template < size_t _Ip,
1254 class... _Args,
1255 enable_if_t<(_Ip < sizeof...(_Types)), int> = 0,
1256 class _Tp = variant_alternative_t<_Ip, variant<_Types...>>,
1257 enable_if_t<is_constructible_v<_Tp, _Args...>, int> = 0>
1258 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Tp& emplace(_Args&&... __args) {
1259 return __impl_.template __emplace<_Ip>(std::forward<_Args>(__args)...);
1260 }
1261
1262 template < size_t _Ip,
1263 class _Up,
1264 class... _Args,
1265 enable_if_t<(_Ip < sizeof...(_Types)), int> = 0,
1266 class _Tp = variant_alternative_t<_Ip, variant<_Types...>>,
1267 enable_if_t<is_constructible_v<_Tp, initializer_list<_Up>&, _Args...>, int> = 0>
1268 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Tp& emplace(initializer_list<_Up> __il, _Args&&... __args) {
1269 return __impl_.template __emplace<_Ip>(__il, std::forward<_Args>(__args)...);
1270 }
1271
1272 template < class _Tp,
1273 class... _Args,
1274 size_t _Ip = __find_detail::__find_unambiguous_index_sfinae<_Tp, _Types...>::value,
1275 enable_if_t<is_constructible_v<_Tp, _Args...>, int> = 0>
1276 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Tp& emplace(_Args&&... __args) {
1277 return __impl_.template __emplace<_Ip>(std::forward<_Args>(__args)...);
1278 }
1279
1280 template < class _Tp,
1281 class _Up,
1282 class... _Args,
1283 size_t _Ip = __find_detail::__find_unambiguous_index_sfinae<_Tp, _Types...>::value,
1284 enable_if_t<is_constructible_v<_Tp, initializer_list<_Up>&, _Args...>, int> = 0>
1285 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Tp& emplace(initializer_list<_Up> __il, _Args&&... __args) {
1286 return __impl_.template __emplace<_Ip>(__il, std::forward<_Args>(__args)...);
1287 }
1288
1289 _LIBCPP_HIDE_FROM_ABI constexpr bool valueless_by_exception() const noexcept {
1290 return __impl_.valueless_by_exception();
1291 }
1292
1293 _LIBCPP_HIDE_FROM_ABI constexpr size_t index() const noexcept { return __impl_.index(); }
1294
1295 template < bool _Dummy = true,
1296 enable_if_t< __all<(__dependent_type<is_move_constructible<_Types>, _Dummy>::value &&
1297 __dependent_type<is_swappable<_Types>, _Dummy>::value)...>::value,
1298 int> = 0>
1299 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void swap(variant& __that) noexcept(
1300 __all<(is_nothrow_move_constructible_v<_Types> && is_nothrow_swappable_v<_Types>)...>::value) {
1301 __impl_.__swap(__that.__impl_);
1302 }
1303
1304 # if _LIBCPP_STD_VER >= 26 && _LIBCPP_HAS_EXPLICIT_THIS_PARAMETER
1305 // Helper class to implement [variant.visit]/10
1306 // Constraints: The call to visit does not use an explicit template-argument-list
1307 // that begins with a type template-argument.
1308 struct __variant_visit_barrier_tag {
1309 _LIBCPP_HIDE_FROM_ABI explicit __variant_visit_barrier_tag() = default;
1310 };
1311
1312 template <__variant_visit_barrier_tag = __variant_visit_barrier_tag{}, class _Self, class _Visitor>
1313 _LIBCPP_HIDE_FROM_ABI constexpr decltype(auto) visit(this _Self&& __self, _Visitor&& __visitor) {
1314 return std::visit(std::forward<_Visitor>(__visitor), std::__forward_as<_Self, variant>(__self));
1315 }
1316
1317 template <class _Rp, class _Self, class _Visitor>
1318 _LIBCPP_HIDE_FROM_ABI constexpr _Rp visit(this _Self&& __self, _Visitor&& __visitor) {
1319 return std::visit<_Rp>(std::forward<_Visitor>(__visitor), std::__forward_as<_Self, variant>(__self));
1320 }
1321 # endif
1322
1323 private:
1324 __variant_detail::__impl<_Types...> __impl_;
1325
1326 friend struct __variant_detail::__access::__variant;
1327 friend struct __variant_detail::__visitation::__variant;
1328 };
1329
1330 template <size_t _Ip, class... _Types>
1331 _LIBCPP_HIDE_FROM_ABI constexpr bool __holds_alternative(const variant<_Types...>& __v) noexcept {
1332 return __v.index() == _Ip;
1333 }
1334
1335 template <class _Tp, class... _Types>
1336 _LIBCPP_HIDE_FROM_ABI constexpr bool holds_alternative(const variant<_Types...>& __v) noexcept {
1337 return std::__holds_alternative<__find_exactly_one_t<_Tp, _Types...>::value>(__v);
1338 }
1339
1340 template <size_t _Ip, class _Vp>
1341 _LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS constexpr auto&& __generic_get(_Vp&& __v) {
1342 using __variant_detail::__access::__variant;
1343 if (!std::__holds_alternative<_Ip>(__v)) {
1344 __throw_bad_variant_access();
1345 }
1346 return __variant::__get_alt<_Ip>(std::forward<_Vp>(__v)).__value;
1347 }
1348
1349 template <size_t _Ip, class... _Types>
1350 _LIBCPP_HIDE_FROM_ABI
1351 _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS constexpr variant_alternative_t<_Ip, variant<_Types...>>&
1352 get(variant<_Types...>& __v) {
1353 static_assert(_Ip < sizeof...(_Types));
1354 static_assert(!is_void_v<variant_alternative_t<_Ip, variant<_Types...>>>);
1355 return std::__generic_get<_Ip>(__v);
1356 }
1357
1358 template <size_t _Ip, class... _Types>
1359 _LIBCPP_HIDE_FROM_ABI
1360 _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS constexpr variant_alternative_t<_Ip, variant<_Types...>>&&
1361 get(variant<_Types...>&& __v) {
1362 static_assert(_Ip < sizeof...(_Types));
1363 static_assert(!is_void_v<variant_alternative_t<_Ip, variant<_Types...>>>);
1364 return std::__generic_get<_Ip>(std::move(__v));
1365 }
1366
1367 template <size_t _Ip, class... _Types>
1368 _LIBCPP_HIDE_FROM_ABI
1369 _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS constexpr const variant_alternative_t<_Ip, variant<_Types...>>&
1370 get(const variant<_Types...>& __v) {
1371 static_assert(_Ip < sizeof...(_Types));
1372 static_assert(!is_void_v<variant_alternative_t<_Ip, variant<_Types...>>>);
1373 return std::__generic_get<_Ip>(__v);
1374 }
1375
1376 template <size_t _Ip, class... _Types>
1377 _LIBCPP_HIDE_FROM_ABI
1378 _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS constexpr const variant_alternative_t<_Ip, variant<_Types...>>&&
1379 get(const variant<_Types...>&& __v) {
1380 static_assert(_Ip < sizeof...(_Types));
1381 static_assert(!is_void_v<variant_alternative_t<_Ip, variant<_Types...>>>);
1382 return std::__generic_get<_Ip>(std::move(__v));
1383 }
1384
1385 template <class _Tp, class... _Types>
1386 _LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS constexpr _Tp& get(variant<_Types...>& __v) {
1387 static_assert(!is_void_v<_Tp>);
1388 return std::get<__find_exactly_one_t<_Tp, _Types...>::value>(__v);
1389 }
1390
1391 template <class _Tp, class... _Types>
1392 _LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS constexpr _Tp&& get(variant<_Types...>&& __v) {
1393 static_assert(!is_void_v<_Tp>);
1394 return std::get<__find_exactly_one_t<_Tp, _Types...>::value>(std::move(__v));
1395 }
1396
1397 template <class _Tp, class... _Types>
1398 _LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS constexpr const _Tp&
1399 get(const variant<_Types...>& __v) {
1400 static_assert(!is_void_v<_Tp>);
1401 return std::get<__find_exactly_one_t<_Tp, _Types...>::value>(__v);
1402 }
1403
1404 template <class _Tp, class... _Types>
1405 _LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS constexpr const _Tp&&
1406 get(const variant<_Types...>&& __v) {
1407 static_assert(!is_void_v<_Tp>);
1408 return std::get<__find_exactly_one_t<_Tp, _Types...>::value>(std::move(__v));
1409 }
1410
1411 template <size_t _Ip, class _Vp>
1412 _LIBCPP_HIDE_FROM_ABI constexpr auto* __generic_get_if(_Vp* __v) noexcept {
1413 using __variant_detail::__access::__variant;
1414 return __v && std::__holds_alternative<_Ip>(*__v) ? std::addressof(__variant::__get_alt<_Ip>(*__v).__value) : nullptr;
1415 }
1416
1417 template <size_t _Ip, class... _Types>
1418 _LIBCPP_HIDE_FROM_ABI constexpr add_pointer_t<variant_alternative_t<_Ip, variant<_Types...>>>
1419 get_if(variant<_Types...>* __v) noexcept {
1420 static_assert(_Ip < sizeof...(_Types));
1421 static_assert(!is_void_v<variant_alternative_t<_Ip, variant<_Types...>>>);
1422 return std::__generic_get_if<_Ip>(__v);
1423 }
1424
1425 template <size_t _Ip, class... _Types>
1426 _LIBCPP_HIDE_FROM_ABI constexpr add_pointer_t<const variant_alternative_t<_Ip, variant<_Types...>>>
1427 get_if(const variant<_Types...>* __v) noexcept {
1428 static_assert(_Ip < sizeof...(_Types));
1429 static_assert(!is_void_v<variant_alternative_t<_Ip, variant<_Types...>>>);
1430 return std::__generic_get_if<_Ip>(__v);
1431 }
1432
1433 template <class _Tp, class... _Types>
1434 _LIBCPP_HIDE_FROM_ABI constexpr add_pointer_t<_Tp> get_if(variant<_Types...>* __v) noexcept {
1435 static_assert(!is_void_v<_Tp>);
1436 return std::get_if<__find_exactly_one_t<_Tp, _Types...>::value>(__v);
1437 }
1438
1439 template <class _Tp, class... _Types>
1440 _LIBCPP_HIDE_FROM_ABI constexpr add_pointer_t<const _Tp> get_if(const variant<_Types...>* __v) noexcept {
1441 static_assert(!is_void_v<_Tp>);
1442 return std::get_if<__find_exactly_one_t<_Tp, _Types...>::value>(__v);
1443 }
1444
1445 template <class _Operator>
1446 struct __convert_to_bool {
1447 template <class _T1, class _T2>
1448 _LIBCPP_HIDE_FROM_ABI constexpr bool operator()(_T1&& __t1, _T2&& __t2) const {
1449 static_assert(is_convertible<decltype(_Operator{}(std::forward<_T1>(__t1), std::forward<_T2>(__t2))), bool>::value,
1450 "the relational operator does not return a type which is implicitly convertible to bool");
1451 return _Operator{}(std::forward<_T1>(__t1), std::forward<_T2>(__t2));
1452 }
1453 };
1454
1455 template <class... _Types>
1456 _LIBCPP_HIDE_FROM_ABI constexpr bool operator==(const variant<_Types...>& __lhs, const variant<_Types...>& __rhs) {
1457 using __variant_detail::__visitation::__variant;
1458 if (__lhs.index() != __rhs.index())
1459 return false;
1460 if (__lhs.valueless_by_exception())
1461 return true;
1462 return __variant::__visit_value_at(__lhs.index(), __convert_to_bool<equal_to<>>{}, __lhs, __rhs);
1463 }
1464
1465 # if _LIBCPP_STD_VER >= 20
1466
1467 template <class... _Types>
1468 requires(three_way_comparable<_Types> && ...)
1469 _LIBCPP_HIDE_FROM_ABI constexpr common_comparison_category_t<compare_three_way_result_t<_Types>...>
1470 operator<=>(const variant<_Types...>& __lhs, const variant<_Types...>& __rhs) {
1471 using __variant_detail::__visitation::__variant;
1472 using __result_t = common_comparison_category_t<compare_three_way_result_t<_Types>...>;
1473 if (__lhs.valueless_by_exception() && __rhs.valueless_by_exception())
1474 return strong_ordering::equal;
1475 if (__lhs.valueless_by_exception())
1476 return strong_ordering::less;
1477 if (__rhs.valueless_by_exception())
1478 return strong_ordering::greater;
1479 if (auto __c = __lhs.index() <=> __rhs.index(); __c != 0)
1480 return __c;
1481 auto __three_way = []<class _Type>(const _Type& __v, const _Type& __w) -> __result_t { return __v <=> __w; };
1482 return __variant::__visit_value_at(__lhs.index(), __three_way, __lhs, __rhs);
1483 }
1484
1485 # endif // _LIBCPP_STD_VER >= 20
1486
1487 template <class... _Types>
1488 _LIBCPP_HIDE_FROM_ABI constexpr bool operator!=(const variant<_Types...>& __lhs, const variant<_Types...>& __rhs) {
1489 using __variant_detail::__visitation::__variant;
1490 if (__lhs.index() != __rhs.index())
1491 return true;
1492 if (__lhs.valueless_by_exception())
1493 return false;
1494 return __variant::__visit_value_at(__lhs.index(), __convert_to_bool<not_equal_to<>>{}, __lhs, __rhs);
1495 }
1496
1497 template <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 (__rhs.valueless_by_exception())
1501 return false;
1502 if (__lhs.valueless_by_exception())
1503 return true;
1504 if (__lhs.index() < __rhs.index())
1505 return true;
1506 if (__lhs.index() > __rhs.index())
1507 return false;
1508 return __variant::__visit_value_at(__lhs.index(), __convert_to_bool<less<>>{}, __lhs, __rhs);
1509 }
1510
1511 template <class... _Types>
1512 _LIBCPP_HIDE_FROM_ABI constexpr bool operator>(const variant<_Types...>& __lhs, const variant<_Types...>& __rhs) {
1513 using __variant_detail::__visitation::__variant;
1514 if (__lhs.valueless_by_exception())
1515 return false;
1516 if (__rhs.valueless_by_exception())
1517 return true;
1518 if (__lhs.index() > __rhs.index())
1519 return true;
1520 if (__lhs.index() < __rhs.index())
1521 return false;
1522 return __variant::__visit_value_at(__lhs.index(), __convert_to_bool<greater<>>{}, __lhs, __rhs);
1523 }
1524
1525 template <class... _Types>
1526 _LIBCPP_HIDE_FROM_ABI constexpr bool operator<=(const variant<_Types...>& __lhs, const variant<_Types...>& __rhs) {
1527 using __variant_detail::__visitation::__variant;
1528 if (__lhs.valueless_by_exception())
1529 return true;
1530 if (__rhs.valueless_by_exception())
1531 return false;
1532 if (__lhs.index() < __rhs.index())
1533 return true;
1534 if (__lhs.index() > __rhs.index())
1535 return false;
1536 return __variant::__visit_value_at(__lhs.index(), __convert_to_bool<less_equal<>>{}, __lhs, __rhs);
1537 }
1538
1539 template <class... _Types>
1540 _LIBCPP_HIDE_FROM_ABI constexpr bool operator>=(const variant<_Types...>& __lhs, const variant<_Types...>& __rhs) {
1541 using __variant_detail::__visitation::__variant;
1542 if (__rhs.valueless_by_exception())
1543 return true;
1544 if (__lhs.valueless_by_exception())
1545 return false;
1546 if (__lhs.index() > __rhs.index())
1547 return true;
1548 if (__lhs.index() < __rhs.index())
1549 return false;
1550 return __variant::__visit_value_at(__lhs.index(), __convert_to_bool<greater_equal<>>{}, __lhs, __rhs);
1551 }
1552
1553 template <class... _Vs>
1554 _LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS constexpr void __throw_if_valueless(_Vs&&... __vs) {
1555 const bool __valueless = (... || std::__as_variant(__vs).valueless_by_exception());
1556 if (__valueless) {
1557 __throw_bad_variant_access();
1558 }
1559 }
1560
1561 template < class _Visitor, class... _Vs, typename>
1562 _LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS constexpr decltype(auto)
1563 visit(_Visitor&& __visitor, _Vs&&... __vs) {
1564 using __variant_detail::__visitation::__variant;
1565 std::__throw_if_valueless(std::forward<_Vs>(__vs)...);
1566 return __variant::__visit_value(std::forward<_Visitor>(__visitor), std::forward<_Vs>(__vs)...);
1567 }
1568
1569 # if _LIBCPP_STD_VER >= 20
1570 template < class _Rp, class _Visitor, class... _Vs, typename>
1571 _LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS constexpr _Rp
1572 visit(_Visitor&& __visitor, _Vs&&... __vs) {
1573 using __variant_detail::__visitation::__variant;
1574 std::__throw_if_valueless(std::forward<_Vs>(__vs)...);
1575 return __variant::__visit_value<_Rp>(std::forward<_Visitor>(__visitor), std::forward<_Vs>(__vs)...);
1576 }
1577 # endif
1578
1579 template <class... _Types>
1580 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 auto
1581 swap(variant<_Types...>& __lhs,
1582 variant<_Types...>& __rhs) noexcept(noexcept(__lhs.swap(__rhs))) -> decltype(__lhs.swap(__rhs)) {
1583 return __lhs.swap(__rhs);
1584 }
1585
1586 template <class... _Types>
1587 struct _LIBCPP_TEMPLATE_VIS hash< __enable_hash_helper<variant<_Types...>, remove_const_t<_Types>...>> {
1588 using argument_type = variant<_Types...>;
1589 using result_type = size_t;
1590
1591 _LIBCPP_HIDE_FROM_ABI result_type operator()(const argument_type& __v) const {
1592 using __variant_detail::__visitation::__variant;
1593 size_t __res =
1594 __v.valueless_by_exception()
1595 ? 299792458 // Random value chosen by the universe upon creation
1596 : __variant::__visit_alt(
1597 [](const auto& __alt) {
1598 using __alt_type = __remove_cvref_t<decltype(__alt)>;
1599 using __value_type = remove_const_t< typename __alt_type::__value_type>;
1600 return hash<__value_type>{}(__alt.__value);
1601 },
1602 __v);
1603 return std::__hash_combine(__res, hash<size_t>{}(__v.index()));
1604 }
1605 };
1606
1607 // __unchecked_get is the same as std::get, except, it is UB to use it with the wrong
1608 // type whereas std::get will throw or returning nullptr. This makes it faster than
1609 // std::get.
1610 template <size_t _Ip, class _Vp>
1611 _LIBCPP_HIDE_FROM_ABI constexpr auto&& __unchecked_get(_Vp&& __v) noexcept {
1612 using __variant_detail::__access::__variant;
1613 return __variant::__get_alt<_Ip>(std::forward<_Vp>(__v)).__value;
1614 }
1615
1616 template <class _Tp, class... _Types>
1617 _LIBCPP_HIDE_FROM_ABI constexpr auto&& __unchecked_get(const variant<_Types...>& __v) noexcept {
1618 return std::__unchecked_get<__find_exactly_one_t<_Tp, _Types...>::value>(__v);
1619 }
1620
1621 template <class _Tp, class... _Types>
1622 _LIBCPP_HIDE_FROM_ABI constexpr auto&& __unchecked_get(variant<_Types...>& __v) noexcept {
1623 return std::__unchecked_get<__find_exactly_one_t<_Tp, _Types...>::value>(__v);
1624 }
1625
1626 # endif // _LIBCPP_STD_VER >= 17
1627
1628 _LIBCPP_END_NAMESPACE_STD
1629
1630 _LIBCPP_POP_MACROS
1631
1632 # if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES) && _LIBCPP_STD_VER <= 20
1633 # include <cstddef>
1634 # include <exception>
1635 # include <tuple>
1636 # include <type_traits>
1637 # include <typeinfo>
1638 # include <utility>
1639 # endif
1640 #endif // __cplusplus < 201103L && defined(_LIBCPP_USE_FROZEN_CXX03_HEADERS)
1641
1642 #endif // _LIBCPP_VARIANT
