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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___CXX03_VARIANT
0011 #define _LIBCPP___CXX03_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 #include <__cxx03/__compare/common_comparison_category.h>
0216 #include <__cxx03/__compare/compare_three_way_result.h>
0217 #include <__cxx03/__compare/three_way_comparable.h>
0218 #include <__cxx03/__config>
0219 #include <__cxx03/__exception/exception.h>
0220 #include <__cxx03/__functional/hash.h>
0221 #include <__cxx03/__functional/invoke.h>
0222 #include <__cxx03/__functional/operations.h>
0223 #include <__cxx03/__functional/unary_function.h>
0224 #include <__cxx03/__memory/addressof.h>
0225 #include <__cxx03/__memory/construct_at.h>
0226 #include <__cxx03/__tuple/find_index.h>
0227 #include <__cxx03/__tuple/sfinae_helpers.h>
0228 #include <__cxx03/__type_traits/add_const.h>
0229 #include <__cxx03/__type_traits/add_cv.h>
0230 #include <__cxx03/__type_traits/add_pointer.h>
0231 #include <__cxx03/__type_traits/add_volatile.h>
0232 #include <__cxx03/__type_traits/common_type.h>
0233 #include <__cxx03/__type_traits/conjunction.h>
0234 #include <__cxx03/__type_traits/dependent_type.h>
0235 #include <__cxx03/__type_traits/is_array.h>
0236 #include <__cxx03/__type_traits/is_constructible.h>
0237 #include <__cxx03/__type_traits/is_destructible.h>
0238 #include <__cxx03/__type_traits/is_nothrow_assignable.h>
0239 #include <__cxx03/__type_traits/is_nothrow_constructible.h>
0240 #include <__cxx03/__type_traits/is_reference.h>
0241 #include <__cxx03/__type_traits/is_trivially_assignable.h>
0242 #include <__cxx03/__type_traits/is_trivially_constructible.h>
0243 #include <__cxx03/__type_traits/is_trivially_destructible.h>
0244 #include <__cxx03/__type_traits/is_trivially_relocatable.h>
0245 #include <__cxx03/__type_traits/is_void.h>
0246 #include <__cxx03/__type_traits/remove_const.h>
0247 #include <__cxx03/__type_traits/remove_cvref.h>
0248 #include <__cxx03/__type_traits/type_identity.h>
0249 #include <__cxx03/__type_traits/void_t.h>
0250 #include <__cxx03/__utility/declval.h>
0251 #include <__cxx03/__utility/forward.h>
0252 #include <__cxx03/__utility/forward_like.h>
0253 #include <__cxx03/__utility/in_place.h>
0254 #include <__cxx03/__utility/integer_sequence.h>
0255 #include <__cxx03/__utility/move.h>
0256 #include <__cxx03/__utility/swap.h>
0257 #include <__cxx03/__variant/monostate.h>
0258 #include <__cxx03/__verbose_abort>
0259 #include <__cxx03/initializer_list>
0260 #include <__cxx03/limits>
0261 #include <__cxx03/new>
0262 #include <__cxx03/version>
0263
0264 // standard-mandated includes
0265
0266 // [variant.syn]
0267 #include <__cxx03/compare>
0268
0269 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
0270 # pragma GCC system_header
0271 #endif
0272
0273 _LIBCPP_PUSH_MACROS
0274 #include <__cxx03/__undef_macros>
0275
0276 namespace std { // explicitly not using versioning namespace
0277
0278 class _LIBCPP_EXPORTED_FROM_ABI _LIBCPP_AVAILABILITY_BAD_VARIANT_ACCESS bad_variant_access : public exception {
0279 public:
0280 const char* what() const _NOEXCEPT override;
0281 };
0282
0283 } // namespace std
0284
0285 _LIBCPP_BEGIN_NAMESPACE_STD
0286
0287 #if _LIBCPP_STD_VER >= 17
0288
0289 // Light N-dimensional array of function pointers. Used in place of std::array to avoid
0290 // adding a dependency.
0291 template <class _Tp, size_t _Size>
0292 struct __farray {
0293 static_assert(_Size > 0, "N-dimensional array should never be empty in std::visit");
0294 _Tp __buf_[_Size] = {};
0295
0296 _LIBCPP_HIDE_FROM_ABI constexpr const _Tp& operator[](size_t __n) const noexcept { return __buf_[__n]; }
0297 };
0298
0299 _LIBCPP_NORETURN inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS void
0300 __throw_bad_variant_access() {
0301 # ifndef _LIBCPP_HAS_NO_EXCEPTIONS
0302 throw bad_variant_access();
0303 # else
0304 _LIBCPP_VERBOSE_ABORT("bad_variant_access was thrown in -fno-exceptions mode");
0305 # endif
0306 }
0307
0308 template <class... _Types>
0309 class _LIBCPP_TEMPLATE_VIS variant;
0310
0311 template <class _Tp>
0312 struct _LIBCPP_TEMPLATE_VIS variant_size;
0313
0314 template <class _Tp>
0315 inline constexpr size_t variant_size_v = variant_size<_Tp>::value;
0316
0317 template <class _Tp>
0318 struct _LIBCPP_TEMPLATE_VIS variant_size<const _Tp> : variant_size<_Tp> {};
0319
0320 template <class _Tp>
0321 struct _LIBCPP_TEMPLATE_VIS variant_size<volatile _Tp> : variant_size<_Tp> {};
0322
0323 template <class _Tp>
0324 struct _LIBCPP_TEMPLATE_VIS variant_size<const volatile _Tp> : variant_size<_Tp> {};
0325
0326 template <class... _Types>
0327 struct _LIBCPP_TEMPLATE_VIS variant_size<variant<_Types...>> : integral_constant<size_t, sizeof...(_Types)> {};
0328
0329 template <size_t _Ip, class _Tp>
0330 struct _LIBCPP_TEMPLATE_VIS variant_alternative;
0331
0332 template <size_t _Ip, class _Tp>
0333 using variant_alternative_t = typename variant_alternative<_Ip, _Tp>::type;
0334
0335 template <size_t _Ip, class _Tp>
0336 struct _LIBCPP_TEMPLATE_VIS variant_alternative<_Ip, const _Tp> : add_const<variant_alternative_t<_Ip, _Tp>> {};
0337
0338 template <size_t _Ip, class _Tp>
0339 struct _LIBCPP_TEMPLATE_VIS variant_alternative<_Ip, volatile _Tp> : add_volatile<variant_alternative_t<_Ip, _Tp>> {};
0340
0341 template <size_t _Ip, class _Tp>
0342 struct _LIBCPP_TEMPLATE_VIS variant_alternative<_Ip, const volatile _Tp> : add_cv<variant_alternative_t<_Ip, _Tp>> {};
0343
0344 template <size_t _Ip, class... _Types>
0345 struct _LIBCPP_TEMPLATE_VIS variant_alternative<_Ip, variant<_Types...>> {
0346 static_assert(_Ip < sizeof...(_Types), "Index out of bounds in std::variant_alternative<>");
0347 using type = __type_pack_element<_Ip, _Types...>;
0348 };
0349
0350 inline constexpr size_t variant_npos = static_cast<size_t>(-1);
0351
0352 template <size_t _NumAlternatives>
0353 _LIBCPP_HIDE_FROM_ABI constexpr auto __choose_index_type() {
0354 # ifdef _LIBCPP_ABI_VARIANT_INDEX_TYPE_OPTIMIZATION
0355 if constexpr (_NumAlternatives < numeric_limits<unsigned char>::max())
0356 return static_cast<unsigned char>(0);
0357 else if constexpr (_NumAlternatives < numeric_limits<unsigned short>::max())
0358 return static_cast<unsigned short>(0);
0359 else
0360 # endif // _LIBCPP_ABI_VARIANT_INDEX_TYPE_OPTIMIZATION
0361 return static_cast<unsigned int>(0);
0362 }
0363
0364 template <size_t _NumAlts>
0365 using __variant_index_t = decltype(std::__choose_index_type<_NumAlts>());
0366
0367 template <class _IndexType>
0368 constexpr _IndexType __variant_npos = static_cast<_IndexType>(-1);
0369
0370 template <class... _Types>
0371 class _LIBCPP_TEMPLATE_VIS variant;
0372
0373 template <class... _Types>
0374 _LIBCPP_HIDE_FROM_ABI constexpr variant<_Types...>& __as_variant(variant<_Types...>& __vs) noexcept {
0375 return __vs;
0376 }
0377
0378 template <class... _Types>
0379 _LIBCPP_HIDE_FROM_ABI constexpr const variant<_Types...>& __as_variant(const variant<_Types...>& __vs) noexcept {
0380 return __vs;
0381 }
0382
0383 template <class... _Types>
0384 _LIBCPP_HIDE_FROM_ABI constexpr variant<_Types...>&& __as_variant(variant<_Types...>&& __vs) noexcept {
0385 return std::move(__vs);
0386 }
0387
0388 template <class... _Types>
0389 _LIBCPP_HIDE_FROM_ABI constexpr const variant<_Types...>&& __as_variant(const variant<_Types...>&& __vs) noexcept {
0390 return std::move(__vs);
0391 }
0392
0393 namespace __find_detail {
0394
0395 template <class _Tp, class... _Types>
0396 _LIBCPP_HIDE_FROM_ABI constexpr size_t __find_index() {
0397 constexpr bool __matches[] = {is_same_v<_Tp, _Types>...};
0398 size_t __result = __not_found;
0399 for (size_t __i = 0; __i < sizeof...(_Types); ++__i) {
0400 if (__matches[__i]) {
0401 if (__result != __not_found) {
0402 return __ambiguous;
0403 }
0404 __result = __i;
0405 }
0406 }
0407 return __result;
0408 }
0409
0410 template <size_t _Index>
0411 struct __find_unambiguous_index_sfinae_impl : integral_constant<size_t, _Index> {};
0412
0413 template <>
0414 struct __find_unambiguous_index_sfinae_impl<__not_found> {};
0415
0416 template <>
0417 struct __find_unambiguous_index_sfinae_impl<__ambiguous> {};
0418
0419 template <class _Tp, class... _Types>
0420 struct __find_unambiguous_index_sfinae : __find_unambiguous_index_sfinae_impl<__find_index<_Tp, _Types...>()> {};
0421
0422 } // namespace __find_detail
0423
0424 namespace __variant_detail {
0425
0426 struct __valueless_t {};
0427
0428 enum class _Trait { _TriviallyAvailable, _Available, _Unavailable };
0429
0430 template <typename _Tp, template <typename> class _IsTriviallyAvailable, template <typename> class _IsAvailable>
0431 constexpr _Trait __trait =
0432 _IsTriviallyAvailable<_Tp>::value ? _Trait::_TriviallyAvailable
0433 : _IsAvailable<_Tp>::value
0434 ? _Trait::_Available
0435 : _Trait::_Unavailable;
0436
0437 _LIBCPP_HIDE_FROM_ABI constexpr _Trait __common_trait(initializer_list<_Trait> __traits) {
0438 _Trait __result = _Trait::_TriviallyAvailable;
0439 for (_Trait __t : __traits) {
0440 if (static_cast<int>(__t) > static_cast<int>(__result)) {
0441 __result = __t;
0442 }
0443 }
0444 return __result;
0445 }
0446
0447 template <typename... _Types>
0448 struct __traits {
0449 static constexpr _Trait __copy_constructible_trait =
0450 __variant_detail::__common_trait({__trait<_Types, is_trivially_copy_constructible, is_copy_constructible>...});
0451
0452 static constexpr _Trait __move_constructible_trait =
0453 __variant_detail::__common_trait({__trait<_Types, is_trivially_move_constructible, is_move_constructible>...});
0454
0455 static constexpr _Trait __copy_assignable_trait = __variant_detail::__common_trait(
0456 {__copy_constructible_trait, __trait<_Types, is_trivially_copy_assignable, is_copy_assignable>...});
0457
0458 static constexpr _Trait __move_assignable_trait = __variant_detail::__common_trait(
0459 {__move_constructible_trait, __trait<_Types, is_trivially_move_assignable, is_move_assignable>...});
0460
0461 static constexpr _Trait __destructible_trait =
0462 __variant_detail::__common_trait({__trait<_Types, is_trivially_destructible, is_destructible>...});
0463 };
0464
0465 namespace __access {
0466
0467 struct __union {
0468 template <class _Vp>
0469 _LIBCPP_HIDE_FROM_ABI static constexpr auto&& __get_alt(_Vp&& __v, in_place_index_t<0>) {
0470 return std::forward<_Vp>(__v).__head;
0471 }
0472
0473 template <class _Vp, size_t _Ip>
0474 _LIBCPP_HIDE_FROM_ABI static constexpr auto&& __get_alt(_Vp&& __v, in_place_index_t<_Ip>) {
0475 return __get_alt(std::forward<_Vp>(__v).__tail, in_place_index<_Ip - 1>);
0476 }
0477 };
0478
0479 struct __base {
0480 template <size_t _Ip, class _Vp>
0481 _LIBCPP_HIDE_FROM_ABI static constexpr auto&& __get_alt(_Vp&& __v) {
0482 return __union::__get_alt(std::forward<_Vp>(__v).__data, in_place_index<_Ip>);
0483 }
0484 };
0485
0486 struct __variant {
0487 template <size_t _Ip, class _Vp>
0488 _LIBCPP_HIDE_FROM_ABI static constexpr auto&& __get_alt(_Vp&& __v) {
0489 return __base::__get_alt<_Ip>(std::forward<_Vp>(__v).__impl_);
0490 }
0491 };
0492
0493 } // namespace __access
0494
0495 namespace __visitation {
0496
0497 struct __base {
0498 template <class _Visitor, class... _Vs>
0499 _LIBCPP_HIDE_FROM_ABI static constexpr decltype(auto)
0500 __visit_alt_at(size_t __index, _Visitor&& __visitor, _Vs&&... __vs) {
0501 constexpr auto __fdiagonal = __make_fdiagonal<_Visitor&&, decltype(std::forward<_Vs>(__vs).__as_base())...>();
0502 return __fdiagonal[__index](std::forward<_Visitor>(__visitor), std::forward<_Vs>(__vs).__as_base()...);
0503 }
0504
0505 template <class _Visitor, class... _Vs>
0506 _LIBCPP_HIDE_FROM_ABI static constexpr decltype(auto) __visit_alt(_Visitor&& __visitor, _Vs&&... __vs) {
0507 constexpr auto __fmatrix = __make_fmatrix<_Visitor&&, decltype(std::forward<_Vs>(__vs).__as_base())...>();
0508 return __at(__fmatrix, __vs.index()...)(std::forward<_Visitor>(__visitor), std::forward<_Vs>(__vs).__as_base()...);
0509 }
0510
0511 private:
0512 template <class _Tp>
0513 _LIBCPP_HIDE_FROM_ABI static constexpr const _Tp& __at(const _Tp& __elem) {
0514 return __elem;
0515 }
0516
0517 template <class _Tp, size_t _Np, typename... _Indices>
0518 _LIBCPP_HIDE_FROM_ABI static constexpr auto&&
0519 __at(const __farray<_Tp, _Np>& __elems, size_t __index, _Indices... __indices) {
0520 return __at(__elems[__index], __indices...);
0521 }
0522
0523 template <class _Fp, class... _Fs>
0524 static _LIBCPP_HIDE_FROM_ABI constexpr void __std_visit_visitor_return_type_check() {
0525 static_assert(
0526 __all<is_same_v<_Fp, _Fs>...>::value, "`std::visit` requires the visitor to have a single return type.");
0527 }
0528
0529 template <class... _Fs>
0530 _LIBCPP_HIDE_FROM_ABI static constexpr auto __make_farray(_Fs&&... __fs) {
0531 __std_visit_visitor_return_type_check<__remove_cvref_t<_Fs>...>();
0532 using __result = __farray<common_type_t<__remove_cvref_t<_Fs>...>, sizeof...(_Fs)>;
0533 return __result{{std::forward<_Fs>(__fs)...}};
0534 }
0535
0536 template <size_t... _Is>
0537 struct __dispatcher {
0538 template <class _Fp, class... _Vs>
0539 _LIBCPP_HIDE_FROM_ABI static constexpr decltype(auto) __dispatch(_Fp __f, _Vs... __vs) {
0540 return std::__invoke(static_cast<_Fp>(__f), __access::__base::__get_alt<_Is>(static_cast<_Vs>(__vs))...);
0541 }
0542 };
0543
0544 template <class _Fp, class... _Vs, size_t... _Is>
0545 _LIBCPP_HIDE_FROM_ABI static constexpr auto __make_dispatch(index_sequence<_Is...>) {
0546 return __dispatcher<_Is...>::template __dispatch<_Fp, _Vs...>;
0547 }
0548
0549 template <size_t _Ip, class _Fp, class... _Vs>
0550 _LIBCPP_HIDE_FROM_ABI static constexpr auto __make_fdiagonal_impl() {
0551 return __make_dispatch<_Fp, _Vs...>(index_sequence<((void)__type_identity<_Vs>{}, _Ip)...>{});
0552 }
0553
0554 template <class _Fp, class... _Vs, size_t... _Is>
0555 _LIBCPP_HIDE_FROM_ABI static constexpr auto __make_fdiagonal_impl(index_sequence<_Is...>) {
0556 return __base::__make_farray(__make_fdiagonal_impl<_Is, _Fp, _Vs...>()...);
0557 }
0558
0559 template <class _Fp, class _Vp, class... _Vs>
0560 _LIBCPP_HIDE_FROM_ABI static constexpr auto __make_fdiagonal() {
0561 constexpr size_t __np = __remove_cvref_t<_Vp>::__size();
0562 static_assert(__all<(__np == __remove_cvref_t<_Vs>::__size())...>::value);
0563 return __make_fdiagonal_impl<_Fp, _Vp, _Vs...>(make_index_sequence<__np>{});
0564 }
0565
0566 template <class _Fp, class... _Vs, size_t... _Is>
0567 _LIBCPP_HIDE_FROM_ABI static constexpr auto __make_fmatrix_impl(index_sequence<_Is...> __is) {
0568 return __make_dispatch<_Fp, _Vs...>(__is);
0569 }
0570
0571 template <class _Fp, class... _Vs, size_t... _Is, size_t... _Js, class... _Ls>
0572 _LIBCPP_HIDE_FROM_ABI static constexpr auto
0573 __make_fmatrix_impl(index_sequence<_Is...>, index_sequence<_Js...>, _Ls... __ls) {
0574 return __base::__make_farray(__make_fmatrix_impl<_Fp, _Vs...>(index_sequence<_Is..., _Js>{}, __ls...)...);
0575 }
0576
0577 template <class _Fp, class... _Vs>
0578 _LIBCPP_HIDE_FROM_ABI static constexpr auto __make_fmatrix() {
0579 return __make_fmatrix_impl<_Fp, _Vs...>(
0580 index_sequence<>{}, make_index_sequence<__remove_cvref_t<_Vs>::__size()>{}...);
0581 }
0582 };
0583
0584 struct __variant {
0585 template <class _Visitor, class... _Vs>
0586 _LIBCPP_HIDE_FROM_ABI static constexpr decltype(auto)
0587 __visit_alt_at(size_t __index, _Visitor&& __visitor, _Vs&&... __vs) {
0588 return __base::__visit_alt_at(__index, std::forward<_Visitor>(__visitor), std::forward<_Vs>(__vs).__impl_...);
0589 }
0590
0591 template <class _Visitor, class... _Vs>
0592 _LIBCPP_HIDE_FROM_ABI static constexpr decltype(auto) __visit_alt(_Visitor&& __visitor, _Vs&&... __vs) {
0593 return __base::__visit_alt(
0594 std::forward<_Visitor>(__visitor), std::__as_variant(std::forward<_Vs>(__vs)).__impl_...);
0595 }
0596
0597 template <class _Visitor, class... _Vs>
0598 _LIBCPP_HIDE_FROM_ABI static constexpr decltype(auto)
0599 __visit_value_at(size_t __index, _Visitor&& __visitor, _Vs&&... __vs) {
0600 return __visit_alt_at(__index, __make_value_visitor(std::forward<_Visitor>(__visitor)), std::forward<_Vs>(__vs)...);
0601 }
0602
0603 template <class _Visitor, class... _Vs>
0604 _LIBCPP_HIDE_FROM_ABI static constexpr decltype(auto) __visit_value(_Visitor&& __visitor, _Vs&&... __vs) {
0605 return __visit_alt(__make_value_visitor(std::forward<_Visitor>(__visitor)), std::forward<_Vs>(__vs)...);
0606 }
0607
0608 # if _LIBCPP_STD_VER >= 20
0609 template <class _Rp, class _Visitor, class... _Vs>
0610 _LIBCPP_HIDE_FROM_ABI static constexpr _Rp __visit_value(_Visitor&& __visitor, _Vs&&... __vs) {
0611 return __visit_alt(__make_value_visitor<_Rp>(std::forward<_Visitor>(__visitor)), std::forward<_Vs>(__vs)...);
0612 }
0613 # endif
0614
0615 private:
0616 template <class _Visitor, class... _Values>
0617 static _LIBCPP_HIDE_FROM_ABI constexpr void __std_visit_exhaustive_visitor_check() {
0618 static_assert(is_invocable_v<_Visitor, _Values...>, "`std::visit` requires the visitor to be exhaustive.");
0619 }
0620
0621 template <class _Visitor>
0622 struct __value_visitor {
0623 template <class... _Alts>
0624 _LIBCPP_HIDE_FROM_ABI constexpr decltype(auto) operator()(_Alts&&... __alts) const {
0625 __std_visit_exhaustive_visitor_check< _Visitor, decltype((std::forward<_Alts>(__alts).__value))...>();
0626 return std::__invoke(std::forward<_Visitor>(__visitor), std::forward<_Alts>(__alts).__value...);
0627 }
0628 _Visitor&& __visitor;
0629 };
0630
0631 # if _LIBCPP_STD_VER >= 20
0632 template <class _Rp, class _Visitor>
0633 struct __value_visitor_return_type {
0634 template <class... _Alts>
0635 _LIBCPP_HIDE_FROM_ABI constexpr _Rp operator()(_Alts&&... __alts) const {
0636 __std_visit_exhaustive_visitor_check< _Visitor, decltype((std::forward<_Alts>(__alts).__value))...>();
0637 if constexpr (is_void_v<_Rp>) {
0638 std::__invoke(std::forward<_Visitor>(__visitor), std::forward<_Alts>(__alts).__value...);
0639 } else {
0640 return std::__invoke(std::forward<_Visitor>(__visitor), std::forward<_Alts>(__alts).__value...);
0641 }
0642 }
0643
0644 _Visitor&& __visitor;
0645 };
0646 # endif
0647
0648 template <class _Visitor>
0649 _LIBCPP_HIDE_FROM_ABI static constexpr auto __make_value_visitor(_Visitor&& __visitor) {
0650 return __value_visitor<_Visitor>{std::forward<_Visitor>(__visitor)};
0651 }
0652
0653 # if _LIBCPP_STD_VER >= 20
0654 template <class _Rp, class _Visitor>
0655 _LIBCPP_HIDE_FROM_ABI static constexpr auto __make_value_visitor(_Visitor&& __visitor) {
0656 return __value_visitor_return_type<_Rp, _Visitor>{std::forward<_Visitor>(__visitor)};
0657 }
0658 # endif
0659 };
0660
0661 } // namespace __visitation
0662
0663 // Adding semi-colons in macro expansions helps clang-format to do a better job.
0664 // This macro is used to avoid compilation errors due to "stray" semi-colons.
0665 # define _LIBCPP_EAT_SEMICOLON static_assert(true, "")
0666
0667 template <size_t _Index, class _Tp>
0668 struct _LIBCPP_TEMPLATE_VIS __alt {
0669 using __value_type = _Tp;
0670 static constexpr size_t __index = _Index;
0671
0672 template <class... _Args>
0673 _LIBCPP_HIDE_FROM_ABI explicit constexpr __alt(in_place_t, _Args&&... __args)
0674 : __value(std::forward<_Args>(__args)...) {}
0675
0676 __value_type __value;
0677 };
0678
0679 template <_Trait _DestructibleTrait, size_t _Index, class... _Types>
0680 union _LIBCPP_TEMPLATE_VIS __union;
0681
0682 template <_Trait _DestructibleTrait, size_t _Index>
0683 union _LIBCPP_TEMPLATE_VIS __union<_DestructibleTrait, _Index> {};
0684
0685 # define _LIBCPP_VARIANT_UNION(destructible_trait, destructor_definition) \
0686 template <size_t _Index, class _Tp, class... _Types> \
0687 union _LIBCPP_TEMPLATE_VIS __union<destructible_trait, _Index, _Tp, _Types...> { \
0688 public: \
0689 _LIBCPP_HIDE_FROM_ABI explicit constexpr __union(__valueless_t) noexcept : __dummy{} {} \
0690 \
0691 template <class... _Args> \
0692 _LIBCPP_HIDE_FROM_ABI explicit constexpr __union(in_place_index_t<0>, _Args&&... __args) \
0693 : __head(in_place, std::forward<_Args>(__args)...) {} \
0694 \
0695 template <size_t _Ip, class... _Args> \
0696 _LIBCPP_HIDE_FROM_ABI explicit constexpr __union(in_place_index_t<_Ip>, _Args&&... __args) \
0697 : __tail(in_place_index<_Ip - 1>, std::forward<_Args>(__args)...) {} \
0698 \
0699 _LIBCPP_HIDE_FROM_ABI __union(const __union&) = default; \
0700 _LIBCPP_HIDE_FROM_ABI __union(__union&&) = default; \
0701 _LIBCPP_HIDE_FROM_ABI __union& operator=(const __union&) = default; \
0702 _LIBCPP_HIDE_FROM_ABI __union& operator=(__union&&) = default; \
0703 destructor_definition; \
0704 \
0705 private: \
0706 char __dummy; \
0707 __alt<_Index, _Tp> __head; \
0708 __union<destructible_trait, _Index + 1, _Types...> __tail; \
0709 \
0710 friend struct __access::__union; \
0711 }
0712
0713 _LIBCPP_VARIANT_UNION(_Trait::_TriviallyAvailable,
0714 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 ~__union() = default);
0715 _LIBCPP_VARIANT_UNION(
0716 _Trait::_Available, _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 ~__union() {} _LIBCPP_EAT_SEMICOLON);
0717 _LIBCPP_VARIANT_UNION(_Trait::_Unavailable, _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 ~__union() = delete);
0718
0719 # undef _LIBCPP_VARIANT_UNION
0720
0721 template <_Trait _DestructibleTrait, class... _Types>
0722 class _LIBCPP_TEMPLATE_VIS __base {
0723 public:
0724 using __index_t = __variant_index_t<sizeof...(_Types)>;
0725
0726 _LIBCPP_HIDE_FROM_ABI explicit constexpr __base(__valueless_t __tag) noexcept
0727 : __data(__tag), __index(__variant_npos<__index_t>) {}
0728
0729 template <size_t _Ip, class... _Args>
0730 _LIBCPP_HIDE_FROM_ABI explicit constexpr __base(in_place_index_t<_Ip>, _Args&&... __args)
0731 : __data(in_place_index<_Ip>, std::forward<_Args>(__args)...), __index(_Ip) {}
0732
0733 _LIBCPP_HIDE_FROM_ABI constexpr bool valueless_by_exception() const noexcept { return index() == variant_npos; }
0734
0735 _LIBCPP_HIDE_FROM_ABI constexpr size_t index() const noexcept {
0736 return __index == __variant_npos<__index_t> ? variant_npos : __index;
0737 }
0738
0739 protected:
0740 _LIBCPP_HIDE_FROM_ABI constexpr auto&& __as_base() & { return *this; }
0741
0742 _LIBCPP_HIDE_FROM_ABI constexpr auto&& __as_base() && { return std::move(*this); }
0743
0744 _LIBCPP_HIDE_FROM_ABI constexpr auto&& __as_base() const& { return *this; }
0745
0746 _LIBCPP_HIDE_FROM_ABI constexpr auto&& __as_base() const&& { return std::move(*this); }
0747
0748 _LIBCPP_HIDE_FROM_ABI static constexpr size_t __size() { return sizeof...(_Types); }
0749
0750 __union<_DestructibleTrait, 0, _Types...> __data;
0751 __index_t __index;
0752
0753 friend struct __access::__base;
0754 friend struct __visitation::__base;
0755 };
0756
0757 template <class _Traits, _Trait = _Traits::__destructible_trait>
0758 class _LIBCPP_TEMPLATE_VIS __dtor;
0759
0760 # define _LIBCPP_VARIANT_DESTRUCTOR(destructible_trait, destructor_definition, destroy) \
0761 template <class... _Types> \
0762 class _LIBCPP_TEMPLATE_VIS __dtor<__traits<_Types...>, destructible_trait> \
0763 : public __base<destructible_trait, _Types...> { \
0764 using __base_type = __base<destructible_trait, _Types...>; \
0765 using __index_t = typename __base_type::__index_t; \
0766 \
0767 public: \
0768 using __base_type::__base_type; \
0769 using __base_type::operator=; \
0770 _LIBCPP_HIDE_FROM_ABI __dtor(const __dtor&) = default; \
0771 _LIBCPP_HIDE_FROM_ABI __dtor(__dtor&&) = default; \
0772 _LIBCPP_HIDE_FROM_ABI __dtor& operator=(const __dtor&) = default; \
0773 _LIBCPP_HIDE_FROM_ABI __dtor& operator=(__dtor&&) = default; \
0774 destructor_definition; \
0775 \
0776 protected: \
0777 destroy; \
0778 }
0779
0780 _LIBCPP_VARIANT_DESTRUCTOR(
0781 _Trait::_TriviallyAvailable,
0782 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 ~__dtor() = default,
0783 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __destroy() noexcept {
0784 this->__index = __variant_npos<__index_t>;
0785 } _LIBCPP_EAT_SEMICOLON);
0786
0787 _LIBCPP_VARIANT_DESTRUCTOR(
0788 _Trait::_Available,
0789 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 ~__dtor() { __destroy(); } _LIBCPP_EAT_SEMICOLON,
0790 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __destroy() noexcept {
0791 if (!this->valueless_by_exception()) {
0792 __visitation::__base::__visit_alt(
0793 [](auto& __alt) noexcept {
0794 using __alt_type = __remove_cvref_t<decltype(__alt)>;
0795 __alt.~__alt_type();
0796 },
0797 *this);
0798 }
0799 this->__index = __variant_npos<__index_t>;
0800 } _LIBCPP_EAT_SEMICOLON);
0801
0802 _LIBCPP_VARIANT_DESTRUCTOR(_Trait::_Unavailable,
0803 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 ~__dtor() = delete,
0804 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __destroy() noexcept = delete);
0805
0806 # undef _LIBCPP_VARIANT_DESTRUCTOR
0807
0808 template <class _Traits>
0809 class _LIBCPP_TEMPLATE_VIS __ctor : public __dtor<_Traits> {
0810 using __base_type = __dtor<_Traits>;
0811
0812 public:
0813 using __base_type::__base_type;
0814 using __base_type::operator=;
0815
0816 protected:
0817 template <class _Rhs>
0818 _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR_SINCE_CXX20 void __generic_construct(__ctor& __lhs, _Rhs&& __rhs) {
0819 __lhs.__destroy();
0820 if (!__rhs.valueless_by_exception()) {
0821 auto __rhs_index = __rhs.index();
0822 __visitation::__base::__visit_alt_at(
0823 __rhs_index,
0824 [&__lhs](auto&& __rhs_alt) {
0825 std::__construct_at(std::addressof(__lhs.__data),
0826 in_place_index<__decay_t<decltype(__rhs_alt)>::__index>,
0827 std::forward<decltype(__rhs_alt)>(__rhs_alt).__value);
0828 },
0829 std::forward<_Rhs>(__rhs));
0830 __lhs.__index = __rhs_index;
0831 }
0832 }
0833 };
0834
0835 template <class _Traits, _Trait = _Traits::__move_constructible_trait>
0836 class _LIBCPP_TEMPLATE_VIS __move_constructor;
0837
0838 # define _LIBCPP_VARIANT_MOVE_CONSTRUCTOR(move_constructible_trait, move_constructor_definition) \
0839 template <class... _Types> \
0840 class _LIBCPP_TEMPLATE_VIS __move_constructor<__traits<_Types...>, move_constructible_trait> \
0841 : public __ctor<__traits<_Types...>> { \
0842 using __base_type = __ctor<__traits<_Types...>>; \
0843 \
0844 public: \
0845 using __base_type::__base_type; \
0846 using __base_type::operator=; \
0847 \
0848 _LIBCPP_HIDE_FROM_ABI __move_constructor(const __move_constructor&) = default; \
0849 _LIBCPP_HIDE_FROM_ABI ~__move_constructor() = default; \
0850 _LIBCPP_HIDE_FROM_ABI __move_constructor& operator=(const __move_constructor&) = default; \
0851 _LIBCPP_HIDE_FROM_ABI __move_constructor& operator=(__move_constructor&&) = default; \
0852 move_constructor_definition; \
0853 }
0854
0855 _LIBCPP_VARIANT_MOVE_CONSTRUCTOR(
0856 _Trait::_TriviallyAvailable,
0857 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __move_constructor(__move_constructor&& __that) = default);
0858
0859 _LIBCPP_VARIANT_MOVE_CONSTRUCTOR(
0860 _Trait::_Available,
0861 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __move_constructor(__move_constructor&& __that) noexcept(
0862 __all<is_nothrow_move_constructible_v<_Types>...>::value)
0863 : __move_constructor(__valueless_t{}) {
0864 this->__generic_construct(*this, std::move(__that));
0865 } _LIBCPP_EAT_SEMICOLON);
0866
0867 _LIBCPP_VARIANT_MOVE_CONSTRUCTOR(
0868 _Trait::_Unavailable,
0869 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __move_constructor(__move_constructor&&) = delete);
0870
0871 # undef _LIBCPP_VARIANT_MOVE_CONSTRUCTOR
0872
0873 template <class _Traits, _Trait = _Traits::__copy_constructible_trait>
0874 class _LIBCPP_TEMPLATE_VIS __copy_constructor;
0875
0876 # define _LIBCPP_VARIANT_COPY_CONSTRUCTOR(copy_constructible_trait, copy_constructor_definition) \
0877 template <class... _Types> \
0878 class _LIBCPP_TEMPLATE_VIS __copy_constructor<__traits<_Types...>, copy_constructible_trait> \
0879 : public __move_constructor<__traits<_Types...>> { \
0880 using __base_type = __move_constructor<__traits<_Types...>>; \
0881 \
0882 public: \
0883 using __base_type::__base_type; \
0884 using __base_type::operator=; \
0885 \
0886 _LIBCPP_HIDE_FROM_ABI __copy_constructor(__copy_constructor&&) = default; \
0887 _LIBCPP_HIDE_FROM_ABI ~__copy_constructor() = default; \
0888 _LIBCPP_HIDE_FROM_ABI __copy_constructor& operator=(const __copy_constructor&) = default; \
0889 _LIBCPP_HIDE_FROM_ABI __copy_constructor& operator=(__copy_constructor&&) = default; \
0890 copy_constructor_definition; \
0891 }
0892
0893 _LIBCPP_VARIANT_COPY_CONSTRUCTOR(
0894 _Trait::_TriviallyAvailable,
0895 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __copy_constructor(const __copy_constructor& __that) = default);
0896
0897 _LIBCPP_VARIANT_COPY_CONSTRUCTOR(
0898 _Trait::_Available,
0899 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __copy_constructor(const __copy_constructor& __that)
0900 : __copy_constructor(__valueless_t{}) { this->__generic_construct(*this, __that); } _LIBCPP_EAT_SEMICOLON);
0901
0902 _LIBCPP_VARIANT_COPY_CONSTRUCTOR(
0903 _Trait::_Unavailable,
0904 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __copy_constructor(const __copy_constructor&) = delete);
0905
0906 # undef _LIBCPP_VARIANT_COPY_CONSTRUCTOR
0907
0908 template <class _Traits>
0909 class _LIBCPP_TEMPLATE_VIS __assignment : public __copy_constructor<_Traits> {
0910 using __base_type = __copy_constructor<_Traits>;
0911
0912 public:
0913 using __base_type::__base_type;
0914 using __base_type::operator=;
0915
0916 template <size_t _Ip, class... _Args>
0917 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 auto& __emplace(_Args&&... __args) {
0918 this->__destroy();
0919 std::__construct_at(std::addressof(this->__data), in_place_index<_Ip>, std::forward<_Args>(__args)...);
0920 this->__index = _Ip;
0921 return __access::__base::__get_alt<_Ip>(*this).__value;
0922 }
0923
0924 protected:
0925 template <size_t _Ip, class _Tp, class _Arg>
0926 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __assign_alt(__alt<_Ip, _Tp>& __a, _Arg&& __arg) {
0927 if (this->index() == _Ip) {
0928 __a.__value = std::forward<_Arg>(__arg);
0929 } else {
0930 struct {
0931 _LIBCPP_HIDDEN _LIBCPP_CONSTEXPR_SINCE_CXX20 void operator()(true_type) const {
0932 __this->__emplace<_Ip>(std::forward<_Arg>(__arg));
0933 }
0934 _LIBCPP_HIDDEN _LIBCPP_CONSTEXPR_SINCE_CXX20 void operator()(false_type) const {
0935 __this->__emplace<_Ip>(_Tp(std::forward<_Arg>(__arg)));
0936 }
0937 __assignment* __this;
0938 _Arg&& __arg;
0939 } __impl{this, std::forward<_Arg>(__arg)};
0940 __impl(bool_constant < is_nothrow_constructible_v<_Tp, _Arg> || !is_nothrow_move_constructible_v < _Tp >> {});
0941 }
0942 }
0943
0944 template <class _That>
0945 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __generic_assign(_That&& __that) {
0946 if (this->valueless_by_exception() && __that.valueless_by_exception()) {
0947 // do nothing.
0948 } else if (__that.valueless_by_exception()) {
0949 this->__destroy();
0950 } else {
0951 __visitation::__base::__visit_alt_at(
0952 __that.index(),
0953 [this](auto& __this_alt, auto&& __that_alt) {
0954 this->__assign_alt(__this_alt, std::forward<decltype(__that_alt)>(__that_alt).__value);
0955 },
0956 *this,
0957 std::forward<_That>(__that));
0958 }
0959 }
0960 };
0961
0962 template <class _Traits, _Trait = _Traits::__move_assignable_trait>
0963 class _LIBCPP_TEMPLATE_VIS __move_assignment;
0964
0965 # define _LIBCPP_VARIANT_MOVE_ASSIGNMENT(move_assignable_trait, move_assignment_definition) \
0966 template <class... _Types> \
0967 class _LIBCPP_TEMPLATE_VIS __move_assignment<__traits<_Types...>, move_assignable_trait> \
0968 : public __assignment<__traits<_Types...>> { \
0969 using __base_type = __assignment<__traits<_Types...>>; \
0970 \
0971 public: \
0972 using __base_type::__base_type; \
0973 using __base_type::operator=; \
0974 \
0975 _LIBCPP_HIDE_FROM_ABI __move_assignment(const __move_assignment&) = default; \
0976 _LIBCPP_HIDE_FROM_ABI __move_assignment(__move_assignment&&) = default; \
0977 _LIBCPP_HIDE_FROM_ABI ~__move_assignment() = default; \
0978 _LIBCPP_HIDE_FROM_ABI __move_assignment& operator=(const __move_assignment&) = default; \
0979 move_assignment_definition; \
0980 }
0981
0982 _LIBCPP_VARIANT_MOVE_ASSIGNMENT(_Trait::_TriviallyAvailable,
0983 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __move_assignment& operator=(
0984 __move_assignment&& __that) = default);
0985
0986 _LIBCPP_VARIANT_MOVE_ASSIGNMENT(
0987 _Trait::_Available,
0988 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __move_assignment&
0989 operator=(__move_assignment&& __that) noexcept(
0990 __all<(is_nothrow_move_constructible_v<_Types> && is_nothrow_move_assignable_v<_Types>)...>::value) {
0991 this->__generic_assign(std::move(__that));
0992 return *this;
0993 } _LIBCPP_EAT_SEMICOLON);
0994
0995 _LIBCPP_VARIANT_MOVE_ASSIGNMENT(
0996 _Trait::_Unavailable,
0997 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __move_assignment& operator=(__move_assignment&&) = delete);
0998
0999 # undef _LIBCPP_VARIANT_MOVE_ASSIGNMENT
1000
1001 template <class _Traits, _Trait = _Traits::__copy_assignable_trait>
1002 class _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
1039 template <class... _Types>
1040 class _LIBCPP_TEMPLATE_VIS __impl : public __copy_assignment<__traits<_Types...>> {
1041 using __base_type = __copy_assignment<__traits<_Types...>>;
1042
1043 public:
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
1099 private:
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
1106 struct __no_narrowing_check {
1107 template <class _Dest, class _Source>
1108 using _Apply = __type_identity<_Dest>;
1109 };
1110
1111 struct __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
1118 template <class _Dest, class _Source>
1119 using __check_for_narrowing _LIBCPP_NODEBUG =
1120 typename _If< is_arithmetic<_Dest>::value, __narrowing_check, __no_narrowing_check >::template _Apply<_Dest,
1121 _Source>;
1122
1123 template <class _Tp, size_t _Idx>
1124 struct __overload {
1125 template <class _Up>
1126 auto operator()(_Tp, _Up&&) const -> __check_for_narrowing<_Tp, _Up>;
1127 };
1128
1129 template <class... _Bases>
1130 struct __all_overloads : _Bases... {
1131 void operator()() const;
1132 using _Bases::operator()...;
1133 };
1134
1135 template <class _IdxSeq>
1136 struct __make_overloads_imp;
1137
1138 template <size_t... _Idx>
1139 struct __make_overloads_imp<__tuple_indices<_Idx...> > {
1140 template <class... _Types>
1141 using _Apply _LIBCPP_NODEBUG = __all_overloads<__overload<_Types, _Idx>...>;
1142 };
1143
1144 template <class... _Types>
1145 using _MakeOverloads _LIBCPP_NODEBUG =
1146 typename __make_overloads_imp< __make_indices_imp<sizeof...(_Types), 0> >::template _Apply<_Types...>;
1147
1148 template <class _Tp, class... _Types>
1149 using __best_match_t = typename invoke_result_t<_MakeOverloads<_Types...>, _Tp, _Tp>::type;
1150
1151 } // namespace __variant_detail
1152
1153 template <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)
1155 visit(_Visitor&& __visitor, _Vs&&... __vs);
1156
1157 # if _LIBCPP_STD_VER >= 20
1158 template <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
1163 visit(_Visitor&& __visitor, _Vs&&... __vs);
1164 # endif
1165
1166 template <class... _Types>
1167 class _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
1183 public:
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
1333 private:
1334 __variant_detail::__impl<_Types...> __impl_;
1335
1336 friend struct __variant_detail::__access::__variant;
1337 friend struct __variant_detail::__visitation::__variant;
1338 };
1339
1340 template <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
1345 template <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
1350 template <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
1359 template <size_t _Ip, class... _Types>
1360 _LIBCPP_HIDE_FROM_ABI
1361 _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS constexpr variant_alternative_t<_Ip, variant<_Types...>>&
1362 get(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
1368 template <size_t _Ip, class... _Types>
1369 _LIBCPP_HIDE_FROM_ABI
1370 _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS constexpr variant_alternative_t<_Ip, variant<_Types...>>&&
1371 get(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
1377 template <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...>>&
1380 get(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
1386 template <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...>>&&
1389 get(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
1395 template <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
1401 template <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
1407 template <class _Tp, class... _Types>
1408 _LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS constexpr const _Tp&
1409 get(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
1414 template <class _Tp, class... _Types>
1415 _LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS constexpr const _Tp&&
1416 get(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
1421 template <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
1427 template <size_t _Ip, class... _Types>
1428 _LIBCPP_HIDE_FROM_ABI constexpr add_pointer_t<variant_alternative_t<_Ip, variant<_Types...>>>
1429 get_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
1435 template <size_t _Ip, class... _Types>
1436 _LIBCPP_HIDE_FROM_ABI constexpr add_pointer_t<const variant_alternative_t<_Ip, variant<_Types...>>>
1437 get_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
1443 template <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
1449 template <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
1455 template <class _Operator>
1456 struct __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
1465 template <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
1477 template <class... _Types>
1478 requires(three_way_comparable<_Types> && ...)
1479 _LIBCPP_HIDE_FROM_ABI constexpr common_comparison_category_t<compare_three_way_result_t<_Types>...>
1480 operator<=>(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
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 (__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
1507 template <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
1521 template <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
1535 template <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
1549 template <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
1563 template <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
1571 template < class _Visitor, class... _Vs, typename>
1572 _LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS constexpr decltype(auto)
1573 visit(_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
1580 template < class _Rp, class _Visitor, class... _Vs, typename>
1581 _LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS constexpr _Rp
1582 visit(_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
1589 template <class... _Types>
1590 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 auto
1591 swap(variant<_Types...>& __lhs,
1592 variant<_Types...>& __rhs) noexcept(noexcept(__lhs.swap(__rhs))) -> decltype(__lhs.swap(__rhs)) {
1593 return __lhs.swap(__rhs);
1594 }
1595
1596 template <class... _Types>
1597 struct _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.
1620 template <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
1626 template <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
1631 template <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 <__cxx03/exception>
1644 # include <__cxx03/tuple>
1645 # include <__cxx03/type_traits>
1646 # include <__cxx03/typeinfo>
1647 # include <__cxx03/utility>
1648 #endif
1649
1650 #endif // _LIBCPP___CXX03_VARIANT
