| // -*- C++ -*- |
| //===------------------------------ variant -------------------------------===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef _LIBCPP_VARIANT |
| #define _LIBCPP_VARIANT |
| |
| /* |
| variant synopsis |
| |
| namespace std { |
| |
| // 20.7.2, class template variant |
| template <class... Types> |
| class variant { |
| public: |
| |
| // 20.7.2.1, constructors |
| constexpr variant() noexcept(see below); |
| variant(const variant&); // constexpr in C++20 |
| variant(variant&&) noexcept(see below); // constexpr in C++20 |
| |
| template <class T> constexpr variant(T&&) noexcept(see below); |
| |
| template <class T, class... Args> |
| constexpr explicit variant(in_place_type_t<T>, Args&&...); |
| |
| template <class T, class U, class... Args> |
| constexpr explicit variant( |
| in_place_type_t<T>, initializer_list<U>, Args&&...); |
| |
| template <size_t I, class... Args> |
| constexpr explicit variant(in_place_index_t<I>, Args&&...); |
| |
| template <size_t I, class U, class... Args> |
| constexpr explicit variant( |
| in_place_index_t<I>, initializer_list<U>, Args&&...); |
| |
| // 20.7.2.2, destructor |
| ~variant(); |
| |
| // 20.7.2.3, assignment |
| variant& operator=(const variant&); // constexpr in C++20 |
| variant& operator=(variant&&) noexcept(see below); // constexpr in C++20 |
| |
| template <class T> variant& operator=(T&&) noexcept(see below); |
| |
| // 20.7.2.4, modifiers |
| template <class T, class... Args> |
| T& emplace(Args&&...); |
| |
| template <class T, class U, class... Args> |
| T& emplace(initializer_list<U>, Args&&...); |
| |
| template <size_t I, class... Args> |
| variant_alternative_t<I, variant>& emplace(Args&&...); |
| |
| template <size_t I, class U, class... Args> |
| variant_alternative_t<I, variant>& emplace(initializer_list<U>, Args&&...); |
| |
| // 20.7.2.5, value status |
| constexpr bool valueless_by_exception() const noexcept; |
| constexpr size_t index() const noexcept; |
| |
| // 20.7.2.6, swap |
| void swap(variant&) noexcept(see below); |
| }; |
| |
| // 20.7.3, variant helper classes |
| template <class T> struct variant_size; // undefined |
| |
| template <class T> |
| inline constexpr size_t variant_size_v = variant_size<T>::value; |
| |
| template <class T> struct variant_size<const T>; |
| template <class T> struct variant_size<volatile T>; |
| template <class T> struct variant_size<const volatile T>; |
| |
| template <class... Types> |
| struct variant_size<variant<Types...>>; |
| |
| template <size_t I, class T> struct variant_alternative; // undefined |
| |
| template <size_t I, class T> |
| using variant_alternative_t = typename variant_alternative<I, T>::type; |
| |
| template <size_t I, class T> struct variant_alternative<I, const T>; |
| template <size_t I, class T> struct variant_alternative<I, volatile T>; |
| template <size_t I, class T> struct variant_alternative<I, const volatile T>; |
| |
| template <size_t I, class... Types> |
| struct variant_alternative<I, variant<Types...>>; |
| |
| inline constexpr size_t variant_npos = -1; |
| |
| // 20.7.4, value access |
| template <class T, class... Types> |
| constexpr bool holds_alternative(const variant<Types...>&) noexcept; |
| |
| template <size_t I, class... Types> |
| constexpr variant_alternative_t<I, variant<Types...>>& |
| get(variant<Types...>&); |
| |
| template <size_t I, class... Types> |
| constexpr variant_alternative_t<I, variant<Types...>>&& |
| get(variant<Types...>&&); |
| |
| template <size_t I, class... Types> |
| constexpr variant_alternative_t<I, variant<Types...>> const& |
| get(const variant<Types...>&); |
| |
| template <size_t I, class... Types> |
| constexpr variant_alternative_t<I, variant<Types...>> const&& |
| get(const variant<Types...>&&); |
| |
| template <class T, class... Types> |
| constexpr T& get(variant<Types...>&); |
| |
| template <class T, class... Types> |
| constexpr T&& get(variant<Types...>&&); |
| |
| template <class T, class... Types> |
| constexpr const T& get(const variant<Types...>&); |
| |
| template <class T, class... Types> |
| constexpr const T&& get(const variant<Types...>&&); |
| |
| template <size_t I, class... Types> |
| constexpr add_pointer_t<variant_alternative_t<I, variant<Types...>>> |
| get_if(variant<Types...>*) noexcept; |
| |
| template <size_t I, class... Types> |
| constexpr add_pointer_t<const variant_alternative_t<I, variant<Types...>>> |
| get_if(const variant<Types...>*) noexcept; |
| |
| template <class T, class... Types> |
| constexpr add_pointer_t<T> |
| get_if(variant<Types...>*) noexcept; |
| |
| template <class T, class... Types> |
| constexpr add_pointer_t<const T> |
| get_if(const variant<Types...>*) noexcept; |
| |
| // 20.7.5, relational operators |
| template <class... Types> |
| constexpr bool operator==(const variant<Types...>&, const variant<Types...>&); |
| |
| template <class... Types> |
| constexpr bool operator!=(const variant<Types...>&, const variant<Types...>&); |
| |
| template <class... Types> |
| constexpr bool operator<(const variant<Types...>&, const variant<Types...>&); |
| |
| template <class... Types> |
| constexpr bool operator>(const variant<Types...>&, const variant<Types...>&); |
| |
| template <class... Types> |
| constexpr bool operator<=(const variant<Types...>&, const variant<Types...>&); |
| |
| template <class... Types> |
| constexpr bool operator>=(const variant<Types...>&, const variant<Types...>&); |
| |
| // 20.7.6, visitation |
| template <class Visitor, class... Variants> |
| constexpr see below visit(Visitor&&, Variants&&...); |
| |
| // 20.7.7, class monostate |
| struct monostate; |
| |
| // 20.7.8, monostate relational operators |
| constexpr bool operator<(monostate, monostate) noexcept; |
| constexpr bool operator>(monostate, monostate) noexcept; |
| constexpr bool operator<=(monostate, monostate) noexcept; |
| constexpr bool operator>=(monostate, monostate) noexcept; |
| constexpr bool operator==(monostate, monostate) noexcept; |
| constexpr bool operator!=(monostate, monostate) noexcept; |
| |
| // 20.7.9, specialized algorithms |
| template <class... Types> |
| void swap(variant<Types...>&, variant<Types...>&) noexcept(see below); |
| |
| // 20.7.10, class bad_variant_access |
| class bad_variant_access; |
| |
| // 20.7.11, hash support |
| template <class T> struct hash; |
| template <class... Types> struct hash<variant<Types...>>; |
| template <> struct hash<monostate>; |
| |
| } // namespace std |
| |
| */ |
| |
| #include <__config> |
| #include <__tuple> |
| #include <array> |
| #include <exception> |
| #include <functional> |
| #include <initializer_list> |
| #include <new> |
| #include <tuple> |
| #include <type_traits> |
| #include <utility> |
| #include <limits> |
| #include <version> |
| |
| #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) |
| #pragma GCC system_header |
| #endif |
| |
| _LIBCPP_PUSH_MACROS |
| #include <__undef_macros> |
| |
| namespace std { // explicitly not using versioning namespace |
| |
| class _LIBCPP_EXCEPTION_ABI _LIBCPP_AVAILABILITY_BAD_VARIANT_ACCESS bad_variant_access : public exception { |
| public: |
| virtual const char* what() const _NOEXCEPT; |
| }; |
| |
| } // namespace std |
| |
| _LIBCPP_BEGIN_NAMESPACE_STD |
| |
| #if _LIBCPP_STD_VER > 14 |
| |
| _LIBCPP_NORETURN |
| inline _LIBCPP_INLINE_VISIBILITY |
| _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS |
| void __throw_bad_variant_access() { |
| #ifndef _LIBCPP_NO_EXCEPTIONS |
| throw bad_variant_access(); |
| #else |
| _VSTD::abort(); |
| #endif |
| } |
| |
| template <class... _Types> |
| class _LIBCPP_TEMPLATE_VIS variant; |
| |
| template <class _Tp> |
| struct _LIBCPP_TEMPLATE_VIS variant_size; |
| |
| template <class _Tp> |
| _LIBCPP_INLINE_VAR constexpr size_t variant_size_v = variant_size<_Tp>::value; |
| |
| template <class _Tp> |
| struct _LIBCPP_TEMPLATE_VIS variant_size<const _Tp> : variant_size<_Tp> {}; |
| |
| template <class _Tp> |
| struct _LIBCPP_TEMPLATE_VIS variant_size<volatile _Tp> : variant_size<_Tp> {}; |
| |
| template <class _Tp> |
| struct _LIBCPP_TEMPLATE_VIS variant_size<const volatile _Tp> |
| : variant_size<_Tp> {}; |
| |
| template <class... _Types> |
| struct _LIBCPP_TEMPLATE_VIS variant_size<variant<_Types...>> |
| : integral_constant<size_t, sizeof...(_Types)> {}; |
| |
| template <size_t _Ip, class _Tp> |
| struct _LIBCPP_TEMPLATE_VIS variant_alternative; |
| |
| template <size_t _Ip, class _Tp> |
| using variant_alternative_t = typename variant_alternative<_Ip, _Tp>::type; |
| |
| template <size_t _Ip, class _Tp> |
| struct _LIBCPP_TEMPLATE_VIS variant_alternative<_Ip, const _Tp> |
| : add_const<variant_alternative_t<_Ip, _Tp>> {}; |
| |
| template <size_t _Ip, class _Tp> |
| struct _LIBCPP_TEMPLATE_VIS variant_alternative<_Ip, volatile _Tp> |
| : add_volatile<variant_alternative_t<_Ip, _Tp>> {}; |
| |
| template <size_t _Ip, class _Tp> |
| struct _LIBCPP_TEMPLATE_VIS variant_alternative<_Ip, const volatile _Tp> |
| : add_cv<variant_alternative_t<_Ip, _Tp>> {}; |
| |
| template <size_t _Ip, class... _Types> |
| struct _LIBCPP_TEMPLATE_VIS variant_alternative<_Ip, variant<_Types...>> { |
| static_assert(_Ip < sizeof...(_Types), "Index out of bounds in std::variant_alternative<>"); |
| using type = __type_pack_element<_Ip, _Types...>; |
| }; |
| |
| _LIBCPP_INLINE_VAR constexpr size_t variant_npos = static_cast<size_t>(-1); |
| |
| constexpr int __choose_index_type(unsigned int __num_elem) { |
| if (__num_elem < std::numeric_limits<unsigned char>::max()) |
| return 0; |
| if (__num_elem < std::numeric_limits<unsigned short>::max()) |
| return 1; |
| return 2; |
| } |
| |
| template <size_t _NumAlts> |
| using __variant_index_t = |
| #ifndef _LIBCPP_ABI_VARIANT_INDEX_TYPE_OPTIMIZATION |
| unsigned int; |
| #else |
| std::tuple_element_t< |
| __choose_index_type(_NumAlts), |
| std::tuple<unsigned char, unsigned short, unsigned int> |
| >; |
| #endif |
| |
| template <class _IndexType> |
| constexpr _IndexType __variant_npos = static_cast<_IndexType>(-1); |
| |
| namespace __find_detail { |
| |
| template <class _Tp, class... _Types> |
| inline _LIBCPP_INLINE_VISIBILITY |
| constexpr size_t __find_index() { |
| constexpr bool __matches[] = {is_same_v<_Tp, _Types>...}; |
| size_t __result = __not_found; |
| for (size_t __i = 0; __i < sizeof...(_Types); ++__i) { |
| if (__matches[__i]) { |
| if (__result != __not_found) { |
| return __ambiguous; |
| } |
| __result = __i; |
| } |
| } |
| return __result; |
| } |
| |
| template <size_t _Index> |
| struct __find_unambiguous_index_sfinae_impl |
| : integral_constant<size_t, _Index> {}; |
| |
| template <> |
| struct __find_unambiguous_index_sfinae_impl<__not_found> {}; |
| |
| template <> |
| struct __find_unambiguous_index_sfinae_impl<__ambiguous> {}; |
| |
| template <class _Tp, class... _Types> |
| struct __find_unambiguous_index_sfinae |
| : __find_unambiguous_index_sfinae_impl<__find_index<_Tp, _Types...>()> {}; |
| |
| } // namespace __find_detail |
| |
| namespace __variant_detail { |
| |
| struct __valueless_t {}; |
| |
| enum class _Trait { _TriviallyAvailable, _Available, _Unavailable }; |
| |
| template <typename _Tp, |
| template <typename> class _IsTriviallyAvailable, |
| template <typename> class _IsAvailable> |
| constexpr _Trait __trait = |
| _IsTriviallyAvailable<_Tp>::value |
| ? _Trait::_TriviallyAvailable |
| : _IsAvailable<_Tp>::value ? _Trait::_Available : _Trait::_Unavailable; |
| |
| inline _LIBCPP_INLINE_VISIBILITY |
| constexpr _Trait __common_trait(initializer_list<_Trait> __traits) { |
| _Trait __result = _Trait::_TriviallyAvailable; |
| for (_Trait __t : __traits) { |
| if (static_cast<int>(__t) > static_cast<int>(__result)) { |
| __result = __t; |
| } |
| } |
| return __result; |
| } |
| |
| template <typename... _Types> |
| struct __traits { |
| static constexpr _Trait __copy_constructible_trait = |
| __common_trait({__trait<_Types, |
| is_trivially_copy_constructible, |
| is_copy_constructible>...}); |
| |
| static constexpr _Trait __move_constructible_trait = |
| __common_trait({__trait<_Types, |
| is_trivially_move_constructible, |
| is_move_constructible>...}); |
| |
| static constexpr _Trait __copy_assignable_trait = __common_trait( |
| {__copy_constructible_trait, |
| __trait<_Types, is_trivially_copy_assignable, is_copy_assignable>...}); |
| |
| static constexpr _Trait __move_assignable_trait = __common_trait( |
| {__move_constructible_trait, |
| __trait<_Types, is_trivially_move_assignable, is_move_assignable>...}); |
| |
| static constexpr _Trait __destructible_trait = __common_trait( |
| {__trait<_Types, is_trivially_destructible, is_destructible>...}); |
| }; |
| |
| namespace __access { |
| |
| struct __union { |
| template <class _Vp> |
| inline _LIBCPP_INLINE_VISIBILITY |
| static constexpr auto&& __get_alt(_Vp&& __v, in_place_index_t<0>) { |
| return _VSTD::forward<_Vp>(__v).__head; |
| } |
| |
| template <class _Vp, size_t _Ip> |
| inline _LIBCPP_INLINE_VISIBILITY |
| static constexpr auto&& __get_alt(_Vp&& __v, in_place_index_t<_Ip>) { |
| return __get_alt(_VSTD::forward<_Vp>(__v).__tail, in_place_index<_Ip - 1>); |
| } |
| }; |
| |
| struct __base { |
| template <size_t _Ip, class _Vp> |
| inline _LIBCPP_INLINE_VISIBILITY |
| static constexpr auto&& __get_alt(_Vp&& __v) { |
| return __union::__get_alt(_VSTD::forward<_Vp>(__v).__data, |
| in_place_index<_Ip>); |
| } |
| }; |
| |
| struct __variant { |
| template <size_t _Ip, class _Vp> |
| inline _LIBCPP_INLINE_VISIBILITY |
| static constexpr auto&& __get_alt(_Vp&& __v) { |
| return __base::__get_alt<_Ip>(_VSTD::forward<_Vp>(__v).__impl); |
| } |
| }; |
| |
| } // namespace __access |
| |
| namespace __visitation { |
| |
| struct __base { |
| template <class _Visitor, class... _Vs> |
| inline _LIBCPP_INLINE_VISIBILITY |
| static constexpr decltype(auto) |
| __visit_alt_at(size_t __index, _Visitor&& __visitor, _Vs&&... __vs) { |
| constexpr auto __fdiagonal = |
| __make_fdiagonal<_Visitor&&, |
| decltype(_VSTD::forward<_Vs>(__vs).__as_base())...>(); |
| return __fdiagonal[__index](_VSTD::forward<_Visitor>(__visitor), |
| _VSTD::forward<_Vs>(__vs).__as_base()...); |
| } |
| |
| template <class _Visitor, class... _Vs> |
| inline _LIBCPP_INLINE_VISIBILITY |
| static constexpr decltype(auto) __visit_alt(_Visitor&& __visitor, |
| _Vs&&... __vs) { |
| constexpr auto __fmatrix = |
| __make_fmatrix<_Visitor&&, |
| decltype(_VSTD::forward<_Vs>(__vs).__as_base())...>(); |
| return __at(__fmatrix, __vs.index()...)( |
| _VSTD::forward<_Visitor>(__visitor), |
| _VSTD::forward<_Vs>(__vs).__as_base()...); |
| } |
| |
| private: |
| template <class _Tp> |
| inline _LIBCPP_INLINE_VISIBILITY |
| static constexpr const _Tp& __at(const _Tp& __elem) { return __elem; } |
| |
| template <class _Tp, size_t _Np, typename... _Indices> |
| inline _LIBCPP_INLINE_VISIBILITY |
| static constexpr auto&& __at(const array<_Tp, _Np>& __elems, |
| size_t __index, _Indices... __indices) { |
| return __at(__elems[__index], __indices...); |
| } |
| |
| template <class _Fp, class... _Fs> |
| static constexpr void __std_visit_visitor_return_type_check() { |
| static_assert( |
| __all<is_same_v<_Fp, _Fs>...>::value, |
| "`std::visit` requires the visitor to have a single return type."); |
| } |
| |
| template <class... _Fs> |
| inline _LIBCPP_INLINE_VISIBILITY |
| static constexpr auto __make_farray(_Fs&&... __fs) { |
| __std_visit_visitor_return_type_check<__uncvref_t<_Fs>...>(); |
| using __result = array<common_type_t<__uncvref_t<_Fs>...>, sizeof...(_Fs)>; |
| return __result{{_VSTD::forward<_Fs>(__fs)...}}; |
| } |
| |
| template <std::size_t... _Is> |
| struct __dispatcher { |
| template <class _Fp, class... _Vs> |
| inline _LIBCPP_INLINE_VISIBILITY |
| static constexpr decltype(auto) __dispatch(_Fp __f, _Vs... __vs) { |
| return __invoke_constexpr( |
| static_cast<_Fp>(__f), |
| __access::__base::__get_alt<_Is>(static_cast<_Vs>(__vs))...); |
| } |
| }; |
| |
| template <class _Fp, class... _Vs, size_t... _Is> |
| inline _LIBCPP_INLINE_VISIBILITY |
| static constexpr auto __make_dispatch(index_sequence<_Is...>) { |
| return __dispatcher<_Is...>::template __dispatch<_Fp, _Vs...>; |
| } |
| |
| template <size_t _Ip, class _Fp, class... _Vs> |
| inline _LIBCPP_INLINE_VISIBILITY |
| static constexpr auto __make_fdiagonal_impl() { |
| return __make_dispatch<_Fp, _Vs...>( |
| index_sequence<(__identity<_Vs>{}, _Ip)...>{}); |
| } |
| |
| template <class _Fp, class... _Vs, size_t... _Is> |
| inline _LIBCPP_INLINE_VISIBILITY |
| static constexpr auto __make_fdiagonal_impl(index_sequence<_Is...>) { |
| return __base::__make_farray(__make_fdiagonal_impl<_Is, _Fp, _Vs...>()...); |
| } |
| |
| template <class _Fp, class _Vp, class... _Vs> |
| inline _LIBCPP_INLINE_VISIBILITY |
| static constexpr auto __make_fdiagonal() { |
| constexpr size_t _Np = __uncvref_t<_Vp>::__size(); |
| static_assert(__all<(_Np == __uncvref_t<_Vs>::__size())...>::value); |
| return __make_fdiagonal_impl<_Fp, _Vp, _Vs...>(make_index_sequence<_Np>{}); |
| } |
| |
| template <class _Fp, class... _Vs, size_t... _Is> |
| inline _LIBCPP_INLINE_VISIBILITY |
| static constexpr auto __make_fmatrix_impl(index_sequence<_Is...> __is) { |
| return __make_dispatch<_Fp, _Vs...>(__is); |
| } |
| |
| template <class _Fp, class... _Vs, size_t... _Is, size_t... _Js, class... _Ls> |
| inline _LIBCPP_INLINE_VISIBILITY |
| static constexpr auto __make_fmatrix_impl(index_sequence<_Is...>, |
| index_sequence<_Js...>, |
| _Ls... __ls) { |
| return __base::__make_farray(__make_fmatrix_impl<_Fp, _Vs...>( |
| index_sequence<_Is..., _Js>{}, __ls...)...); |
| } |
| |
| template <class _Fp, class... _Vs> |
| inline _LIBCPP_INLINE_VISIBILITY |
| static constexpr auto __make_fmatrix() { |
| return __make_fmatrix_impl<_Fp, _Vs...>( |
| index_sequence<>{}, make_index_sequence<__uncvref_t<_Vs>::__size()>{}...); |
| } |
| }; |
| |
| struct __variant { |
| template <class _Visitor, class... _Vs> |
| inline _LIBCPP_INLINE_VISIBILITY |
| static constexpr decltype(auto) |
| __visit_alt_at(size_t __index, _Visitor&& __visitor, _Vs&&... __vs) { |
| return __base::__visit_alt_at(__index, |
| _VSTD::forward<_Visitor>(__visitor), |
| _VSTD::forward<_Vs>(__vs).__impl...); |
| } |
| |
| template <class _Visitor, class... _Vs> |
| inline _LIBCPP_INLINE_VISIBILITY |
| static constexpr decltype(auto) __visit_alt(_Visitor&& __visitor, |
| _Vs&&... __vs) { |
| return __base::__visit_alt(_VSTD::forward<_Visitor>(__visitor), |
| _VSTD::forward<_Vs>(__vs).__impl...); |
| } |
| |
| template <class _Visitor, class... _Vs> |
| inline _LIBCPP_INLINE_VISIBILITY |
| static constexpr decltype(auto) |
| __visit_value_at(size_t __index, _Visitor&& __visitor, _Vs&&... __vs) { |
| return __visit_alt_at( |
| __index, |
| __make_value_visitor(_VSTD::forward<_Visitor>(__visitor)), |
| _VSTD::forward<_Vs>(__vs)...); |
| } |
| |
| template <class _Visitor, class... _Vs> |
| inline _LIBCPP_INLINE_VISIBILITY |
| static constexpr decltype(auto) __visit_value(_Visitor&& __visitor, |
| _Vs&&... __vs) { |
| return __visit_alt( |
| __make_value_visitor(_VSTD::forward<_Visitor>(__visitor)), |
| _VSTD::forward<_Vs>(__vs)...); |
| } |
| |
| private: |
| template <class _Visitor, class... _Values> |
| static constexpr void __std_visit_exhaustive_visitor_check() { |
| static_assert(is_invocable_v<_Visitor, _Values...>, |
| "`std::visit` requires the visitor to be exhaustive."); |
| } |
| |
| template <class _Visitor> |
| struct __value_visitor { |
| template <class... _Alts> |
| inline _LIBCPP_INLINE_VISIBILITY |
| constexpr decltype(auto) operator()(_Alts&&... __alts) const { |
| __std_visit_exhaustive_visitor_check< |
| _Visitor, |
| decltype((_VSTD::forward<_Alts>(__alts).__value))...>(); |
| return __invoke_constexpr(_VSTD::forward<_Visitor>(__visitor), |
| _VSTD::forward<_Alts>(__alts).__value...); |
| } |
| _Visitor&& __visitor; |
| }; |
| |
| template <class _Visitor> |
| inline _LIBCPP_INLINE_VISIBILITY |
| static constexpr auto __make_value_visitor(_Visitor&& __visitor) { |
| return __value_visitor<_Visitor>{_VSTD::forward<_Visitor>(__visitor)}; |
| } |
| }; |
| |
| } // namespace __visitation |
| |
| template <size_t _Index, class _Tp> |
| struct _LIBCPP_TEMPLATE_VIS __alt { |
| using __value_type = _Tp; |
| |
| template <class... _Args> |
| inline _LIBCPP_INLINE_VISIBILITY |
| explicit constexpr __alt(in_place_t, _Args&&... __args) |
| : __value(_VSTD::forward<_Args>(__args)...) {} |
| |
| __value_type __value; |
| }; |
| |
| template <_Trait _DestructibleTrait, size_t _Index, class... _Types> |
| union _LIBCPP_TEMPLATE_VIS __union; |
| |
| template <_Trait _DestructibleTrait, size_t _Index> |
| union _LIBCPP_TEMPLATE_VIS __union<_DestructibleTrait, _Index> {}; |
| |
| #define _LIBCPP_VARIANT_UNION(destructible_trait, destructor) \ |
| template <size_t _Index, class _Tp, class... _Types> \ |
| union _LIBCPP_TEMPLATE_VIS __union<destructible_trait, \ |
| _Index, \ |
| _Tp, \ |
| _Types...> { \ |
| public: \ |
| inline _LIBCPP_INLINE_VISIBILITY \ |
| explicit constexpr __union(__valueless_t) noexcept : __dummy{} {} \ |
| \ |
| template <class... _Args> \ |
| inline _LIBCPP_INLINE_VISIBILITY \ |
| explicit constexpr __union(in_place_index_t<0>, _Args&&... __args) \ |
| : __head(in_place, _VSTD::forward<_Args>(__args)...) {} \ |
| \ |
| template <size_t _Ip, class... _Args> \ |
| inline _LIBCPP_INLINE_VISIBILITY \ |
| explicit constexpr __union(in_place_index_t<_Ip>, _Args&&... __args) \ |
| : __tail(in_place_index<_Ip - 1>, _VSTD::forward<_Args>(__args)...) {} \ |
| \ |
| __union(const __union&) = default; \ |
| __union(__union&&) = default; \ |
| \ |
| destructor \ |
| \ |
| __union& operator=(const __union&) = default; \ |
| __union& operator=(__union&&) = default; \ |
| \ |
| private: \ |
| char __dummy; \ |
| __alt<_Index, _Tp> __head; \ |
| __union<destructible_trait, _Index + 1, _Types...> __tail; \ |
| \ |
| friend struct __access::__union; \ |
| } |
| |
| _LIBCPP_VARIANT_UNION(_Trait::_TriviallyAvailable, ~__union() = default;); |
| _LIBCPP_VARIANT_UNION(_Trait::_Available, ~__union() {}); |
| _LIBCPP_VARIANT_UNION(_Trait::_Unavailable, ~__union() = delete;); |
| |
| #undef _LIBCPP_VARIANT_UNION |
| |
| template <_Trait _DestructibleTrait, class... _Types> |
| class _LIBCPP_TEMPLATE_VIS __base { |
| public: |
| using __index_t = __variant_index_t<sizeof...(_Types)>; |
| |
| inline _LIBCPP_INLINE_VISIBILITY |
| explicit constexpr __base(__valueless_t tag) noexcept |
| : __data(tag), __index(__variant_npos<__index_t>) {} |
| |
| template <size_t _Ip, class... _Args> |
| inline _LIBCPP_INLINE_VISIBILITY |
| explicit constexpr __base(in_place_index_t<_Ip>, _Args&&... __args) |
| : |
| __data(in_place_index<_Ip>, _VSTD::forward<_Args>(__args)...), |
| __index(_Ip) {} |
| |
| inline _LIBCPP_INLINE_VISIBILITY |
| constexpr bool valueless_by_exception() const noexcept { |
| return index() == variant_npos; |
| } |
| |
| inline _LIBCPP_INLINE_VISIBILITY |
| constexpr size_t index() const noexcept { |
| return __index == __variant_npos<__index_t> ? variant_npos : __index; |
| } |
| |
| protected: |
| inline _LIBCPP_INLINE_VISIBILITY |
| constexpr auto&& __as_base() & { return *this; } |
| |
| inline _LIBCPP_INLINE_VISIBILITY |
| constexpr auto&& __as_base() && { return _VSTD::move(*this); } |
| |
| inline _LIBCPP_INLINE_VISIBILITY |
| constexpr auto&& __as_base() const & { return *this; } |
| |
| inline _LIBCPP_INLINE_VISIBILITY |
| constexpr auto&& __as_base() const && { return _VSTD::move(*this); } |
| |
| inline _LIBCPP_INLINE_VISIBILITY |
| static constexpr size_t __size() { return sizeof...(_Types); } |
| |
| __union<_DestructibleTrait, 0, _Types...> __data; |
| __index_t __index; |
| |
| friend struct __access::__base; |
| friend struct __visitation::__base; |
| }; |
| |
| template <class _Traits, _Trait = _Traits::__destructible_trait> |
| class _LIBCPP_TEMPLATE_VIS __destructor; |
| |
| #define _LIBCPP_VARIANT_DESTRUCTOR(destructible_trait, destructor, destroy) \ |
| template <class... _Types> \ |
| class _LIBCPP_TEMPLATE_VIS __destructor<__traits<_Types...>, \ |
| destructible_trait> \ |
| : public __base<destructible_trait, _Types...> { \ |
| using __base_type = __base<destructible_trait, _Types...>; \ |
| using __index_t = typename __base_type::__index_t; \ |
| \ |
| public: \ |
| using __base_type::__base_type; \ |
| using __base_type::operator=; \ |
| \ |
| __destructor(const __destructor&) = default; \ |
| __destructor(__destructor&&) = default; \ |
| destructor \ |
| __destructor& operator=(const __destructor&) = default; \ |
| __destructor& operator=(__destructor&&) = default; \ |
| \ |
| protected: \ |
| inline _LIBCPP_INLINE_VISIBILITY \ |
| destroy \ |
| } |
| |
| _LIBCPP_VARIANT_DESTRUCTOR( |
| _Trait::_TriviallyAvailable, |
| ~__destructor() = default;, |
| void __destroy() noexcept { this->__index = __variant_npos<__index_t>; }); |
| |
| _LIBCPP_VARIANT_DESTRUCTOR( |
| _Trait::_Available, |
| ~__destructor() { __destroy(); }, |
| void __destroy() noexcept { |
| if (!this->valueless_by_exception()) { |
| __visitation::__base::__visit_alt( |
| [](auto& __alt) noexcept { |
| using __alt_type = __uncvref_t<decltype(__alt)>; |
| __alt.~__alt_type(); |
| }, |
| *this); |
| } |
| this->__index = __variant_npos<__index_t>; |
| }); |
| |
| _LIBCPP_VARIANT_DESTRUCTOR( |
| _Trait::_Unavailable, |
| ~__destructor() = delete;, |
| void __destroy() noexcept = delete;); |
| |
| #undef _LIBCPP_VARIANT_DESTRUCTOR |
| |
| template <class _Traits> |
| class _LIBCPP_TEMPLATE_VIS __constructor : public __destructor<_Traits> { |
| using __base_type = __destructor<_Traits>; |
| |
| public: |
| using __base_type::__base_type; |
| using __base_type::operator=; |
| |
| protected: |
| template <size_t _Ip, class _Tp, class... _Args> |
| inline _LIBCPP_INLINE_VISIBILITY |
| static _Tp& __construct_alt(__alt<_Ip, _Tp>& __a, _Args&&... __args) { |
| ::new ((void*)_VSTD::addressof(__a)) |
| __alt<_Ip, _Tp>(in_place, _VSTD::forward<_Args>(__args)...); |
| return __a.__value; |
| } |
| |
| template <class _Rhs> |
| inline _LIBCPP_INLINE_VISIBILITY |
| static void __generic_construct(__constructor& __lhs, _Rhs&& __rhs) { |
| __lhs.__destroy(); |
| if (!__rhs.valueless_by_exception()) { |
| __visitation::__base::__visit_alt_at( |
| __rhs.index(), |
| [](auto& __lhs_alt, auto&& __rhs_alt) { |
| __construct_alt( |
| __lhs_alt, |
| _VSTD::forward<decltype(__rhs_alt)>(__rhs_alt).__value); |
| }, |
| __lhs, _VSTD::forward<_Rhs>(__rhs)); |
| __lhs.__index = __rhs.index(); |
| } |
| } |
| }; |
| |
| template <class _Traits, _Trait = _Traits::__move_constructible_trait> |
| class _LIBCPP_TEMPLATE_VIS __move_constructor; |
| |
| #define _LIBCPP_VARIANT_MOVE_CONSTRUCTOR(move_constructible_trait, \ |
| move_constructor) \ |
| template <class... _Types> \ |
| class _LIBCPP_TEMPLATE_VIS __move_constructor<__traits<_Types...>, \ |
| move_constructible_trait> \ |
| : public __constructor<__traits<_Types...>> { \ |
| using __base_type = __constructor<__traits<_Types...>>; \ |
| \ |
| public: \ |
| using __base_type::__base_type; \ |
| using __base_type::operator=; \ |
| \ |
| __move_constructor(const __move_constructor&) = default; \ |
| move_constructor \ |
| ~__move_constructor() = default; \ |
| __move_constructor& operator=(const __move_constructor&) = default; \ |
| __move_constructor& operator=(__move_constructor&&) = default; \ |
| } |
| |
| _LIBCPP_VARIANT_MOVE_CONSTRUCTOR( |
| _Trait::_TriviallyAvailable, |
| __move_constructor(__move_constructor&& __that) = default;); |
| |
| _LIBCPP_VARIANT_MOVE_CONSTRUCTOR( |
| _Trait::_Available, |
| __move_constructor(__move_constructor&& __that) noexcept( |
| __all<is_nothrow_move_constructible_v<_Types>...>::value) |
| : __move_constructor(__valueless_t{}) { |
| this->__generic_construct(*this, _VSTD::move(__that)); |
| }); |
| |
| _LIBCPP_VARIANT_MOVE_CONSTRUCTOR( |
| _Trait::_Unavailable, |
| __move_constructor(__move_constructor&&) = delete;); |
| |
| #undef _LIBCPP_VARIANT_MOVE_CONSTRUCTOR |
| |
| template <class _Traits, _Trait = _Traits::__copy_constructible_trait> |
| class _LIBCPP_TEMPLATE_VIS __copy_constructor; |
| |
| #define _LIBCPP_VARIANT_COPY_CONSTRUCTOR(copy_constructible_trait, \ |
| copy_constructor) \ |
| template <class... _Types> \ |
| class _LIBCPP_TEMPLATE_VIS __copy_constructor<__traits<_Types...>, \ |
| copy_constructible_trait> \ |
| : public __move_constructor<__traits<_Types...>> { \ |
| using __base_type = __move_constructor<__traits<_Types...>>; \ |
| \ |
| public: \ |
| using __base_type::__base_type; \ |
| using __base_type::operator=; \ |
| \ |
| copy_constructor \ |
| __copy_constructor(__copy_constructor&&) = default; \ |
| ~__copy_constructor() = default; \ |
| __copy_constructor& operator=(const __copy_constructor&) = default; \ |
| __copy_constructor& operator=(__copy_constructor&&) = default; \ |
| } |
| |
| _LIBCPP_VARIANT_COPY_CONSTRUCTOR( |
| _Trait::_TriviallyAvailable, |
| __copy_constructor(const __copy_constructor& __that) = default;); |
| |
| _LIBCPP_VARIANT_COPY_CONSTRUCTOR( |
| _Trait::_Available, |
| __copy_constructor(const __copy_constructor& __that) |
| : __copy_constructor(__valueless_t{}) { |
| this->__generic_construct(*this, __that); |
| }); |
| |
| _LIBCPP_VARIANT_COPY_CONSTRUCTOR( |
| _Trait::_Unavailable, |
| __copy_constructor(const __copy_constructor&) = delete;); |
| |
| #undef _LIBCPP_VARIANT_COPY_CONSTRUCTOR |
| |
| template <class _Traits> |
| class _LIBCPP_TEMPLATE_VIS __assignment : public __copy_constructor<_Traits> { |
| using __base_type = __copy_constructor<_Traits>; |
| |
| public: |
| using __base_type::__base_type; |
| using __base_type::operator=; |
| |
| template <size_t _Ip, class... _Args> |
| inline _LIBCPP_INLINE_VISIBILITY |
| auto& __emplace(_Args&&... __args) { |
| this->__destroy(); |
| auto& __res = this->__construct_alt(__access::__base::__get_alt<_Ip>(*this), |
| _VSTD::forward<_Args>(__args)...); |
| this->__index = _Ip; |
| return __res; |
| } |
| |
| protected: |
| template <size_t _Ip, class _Tp, class _Arg> |
| inline _LIBCPP_INLINE_VISIBILITY |
| void __assign_alt(__alt<_Ip, _Tp>& __a, _Arg&& __arg) { |
| if (this->index() == _Ip) { |
| __a.__value = _VSTD::forward<_Arg>(__arg); |
| } else { |
| struct { |
| void operator()(true_type) const { |
| __this->__emplace<_Ip>(_VSTD::forward<_Arg>(__arg)); |
| } |
| void operator()(false_type) const { |
| __this->__emplace<_Ip>(_Tp(_VSTD::forward<_Arg>(__arg))); |
| } |
| __assignment* __this; |
| _Arg&& __arg; |
| } __impl{this, _VSTD::forward<_Arg>(__arg)}; |
| __impl(bool_constant<is_nothrow_constructible_v<_Tp, _Arg> || |
| !is_nothrow_move_constructible_v<_Tp>>{}); |
| } |
| } |
| |
| template <class _That> |
| inline _LIBCPP_INLINE_VISIBILITY |
| void __generic_assign(_That&& __that) { |
| if (this->valueless_by_exception() && __that.valueless_by_exception()) { |
| // do nothing. |
| } else if (__that.valueless_by_exception()) { |
| this->__destroy(); |
| } else { |
| __visitation::__base::__visit_alt_at( |
| __that.index(), |
| [this](auto& __this_alt, auto&& __that_alt) { |
| this->__assign_alt( |
| __this_alt, |
| _VSTD::forward<decltype(__that_alt)>(__that_alt).__value); |
| }, |
| *this, _VSTD::forward<_That>(__that)); |
| } |
| } |
| }; |
| |
| template <class _Traits, _Trait = _Traits::__move_assignable_trait> |
| class _LIBCPP_TEMPLATE_VIS __move_assignment; |
| |
| #define _LIBCPP_VARIANT_MOVE_ASSIGNMENT(move_assignable_trait, \ |
| move_assignment) \ |
| template <class... _Types> \ |
| class _LIBCPP_TEMPLATE_VIS __move_assignment<__traits<_Types...>, \ |
| move_assignable_trait> \ |
| : public __assignment<__traits<_Types...>> { \ |
| using __base_type = __assignment<__traits<_Types...>>; \ |
| \ |
| public: \ |
| using __base_type::__base_type; \ |
| using __base_type::operator=; \ |
| \ |
| __move_assignment(const __move_assignment&) = default; \ |
| __move_assignment(__move_assignment&&) = default; \ |
| ~__move_assignment() = default; \ |
| __move_assignment& operator=(const __move_assignment&) = default; \ |
| move_assignment \ |
| } |
| |
| _LIBCPP_VARIANT_MOVE_ASSIGNMENT( |
| _Trait::_TriviallyAvailable, |
| __move_assignment& operator=(__move_assignment&& __that) = default;); |
| |
| _LIBCPP_VARIANT_MOVE_ASSIGNMENT( |
| _Trait::_Available, |
| __move_assignment& operator=(__move_assignment&& __that) noexcept( |
| __all<(is_nothrow_move_constructible_v<_Types> && |
| is_nothrow_move_assignable_v<_Types>)...>::value) { |
| this->__generic_assign(_VSTD::move(__that)); |
| return *this; |
| }); |
| |
| _LIBCPP_VARIANT_MOVE_ASSIGNMENT( |
| _Trait::_Unavailable, |
| __move_assignment& operator=(__move_assignment&&) = delete;); |
| |
| #undef _LIBCPP_VARIANT_MOVE_ASSIGNMENT |
| |
| template <class _Traits, _Trait = _Traits::__copy_assignable_trait> |
| class _LIBCPP_TEMPLATE_VIS __copy_assignment; |
| |
| #define _LIBCPP_VARIANT_COPY_ASSIGNMENT(copy_assignable_trait, \ |
| copy_assignment) \ |
| template <class... _Types> \ |
| class _LIBCPP_TEMPLATE_VIS __copy_assignment<__traits<_Types...>, \ |
| copy_assignable_trait> \ |
| : public __move_assignment<__traits<_Types...>> { \ |
| using __base_type = __move_assignment<__traits<_Types...>>; \ |
| \ |
| public: \ |
| using __base_type::__base_type; \ |
| using __base_type::operator=; \ |
| \ |
| __copy_assignment(const __copy_assignment&) = default; \ |
| __copy_assignment(__copy_assignment&&) = default; \ |
| ~__copy_assignment() = default; \ |
| copy_assignment \ |
| __copy_assignment& operator=(__copy_assignment&&) = default; \ |
| } |
| |
| _LIBCPP_VARIANT_COPY_ASSIGNMENT( |
| _Trait::_TriviallyAvailable, |
| __copy_assignment& operator=(const __copy_assignment& __that) = default;); |
| |
| _LIBCPP_VARIANT_COPY_ASSIGNMENT( |
| _Trait::_Available, |
| __copy_assignment& operator=(const __copy_assignment& __that) { |
| this->__generic_assign(__that); |
| return *this; |
| }); |
| |
| _LIBCPP_VARIANT_COPY_ASSIGNMENT( |
| _Trait::_Unavailable, |
| __copy_assignment& operator=(const __copy_assignment&) = delete;); |
| |
| #undef _LIBCPP_VARIANT_COPY_ASSIGNMENT |
| |
| template <class... _Types> |
| class _LIBCPP_TEMPLATE_VIS __impl |
| : public __copy_assignment<__traits<_Types...>> { |
| using __base_type = __copy_assignment<__traits<_Types...>>; |
| |
| public: |
| using __base_type::__base_type; |
| using __base_type::operator=; |
| |
| template <size_t _Ip, class _Arg> |
| inline _LIBCPP_INLINE_VISIBILITY |
| void __assign(_Arg&& __arg) { |
| this->__assign_alt(__access::__base::__get_alt<_Ip>(*this), |
| _VSTD::forward<_Arg>(__arg)); |
| } |
| |
| inline _LIBCPP_INLINE_VISIBILITY |
| void __swap(__impl& __that) { |
| if (this->valueless_by_exception() && __that.valueless_by_exception()) { |
| // do nothing. |
| } else if (this->index() == __that.index()) { |
| __visitation::__base::__visit_alt_at( |
| this->index(), |
| [](auto& __this_alt, auto& __that_alt) { |
| using _VSTD::swap; |
| swap(__this_alt.__value, __that_alt.__value); |
| }, |
| *this, |
| __that); |
| } else { |
| __impl* __lhs = this; |
| __impl* __rhs = _VSTD::addressof(__that); |
| if (__lhs->__move_nothrow() && !__rhs->__move_nothrow()) { |
| _VSTD::swap(__lhs, __rhs); |
| } |
| __impl __tmp(_VSTD::move(*__rhs)); |
| #ifndef _LIBCPP_NO_EXCEPTIONS |
| // EXTENSION: When the move construction of `__lhs` into `__rhs` throws |
| // and `__tmp` is nothrow move constructible then we move `__tmp` back |
| // into `__rhs` and provide the strong exception safety guarantee. |
| try { |
| this->__generic_construct(*__rhs, _VSTD::move(*__lhs)); |
| } catch (...) { |
| if (__tmp.__move_nothrow()) { |
| this->__generic_construct(*__rhs, _VSTD::move(__tmp)); |
| } |
| throw; |
| } |
| #else |
| this->__generic_construct(*__rhs, _VSTD::move(*__lhs)); |
| #endif |
| this->__generic_construct(*__lhs, _VSTD::move(__tmp)); |
| } |
| } |
| |
| private: |
| inline _LIBCPP_INLINE_VISIBILITY |
| bool __move_nothrow() const { |
| constexpr bool __results[] = {is_nothrow_move_constructible_v<_Types>...}; |
| return this->valueless_by_exception() || __results[this->index()]; |
| } |
| }; |
| |
| template <class... _Types> |
| struct __overload; |
| |
| template <> |
| struct __overload<> { void operator()() const; }; |
| |
| template <class _Tp, class... _Types> |
| struct __overload<_Tp, _Types...> : __overload<_Types...> { |
| using __overload<_Types...>::operator(); |
| |
| static auto __test(_Tp (&&)[1]) -> __identity<_Tp>; |
| |
| template <class _Up> |
| auto operator()(_Tp, _Up&& __t) const |
| -> decltype(__test({ _VSTD::forward<_Up>(__t) })); |
| }; |
| |
| template <class _Base, class _Tp> |
| struct __overload_bool : _Base { |
| using _Base::operator(); |
| |
| template <class _Up, class _Ap = __uncvref_t<_Up>> |
| auto operator()(bool, _Up&&) const |
| -> enable_if_t<is_same_v<_Ap, bool>, __identity<_Tp>>; |
| }; |
| |
| template <class... _Types> |
| struct __overload<bool, _Types...> |
| : __overload_bool<__overload<_Types...>, bool> {}; |
| template <class... _Types> |
| struct __overload<bool const, _Types...> |
| : __overload_bool<__overload<_Types...>, bool const> {}; |
| template <class... _Types> |
| struct __overload<bool volatile, _Types...> |
| : __overload_bool<__overload<_Types...>, bool volatile> {}; |
| template <class... _Types> |
| struct __overload<bool const volatile, _Types...> |
| : __overload_bool<__overload<_Types...>, bool const volatile> {}; |
| |
| template <class _Tp, class... _Types> |
| using __best_match_t = |
| typename invoke_result_t<__overload<_Types...>, _Tp, _Tp>::type; |
| |
| } // __variant_detail |
| |
| template <class... _Types> |
| class _LIBCPP_TEMPLATE_VIS variant |
| : private __sfinae_ctor_base< |
| __all<is_copy_constructible_v<_Types>...>::value, |
| __all<is_move_constructible_v<_Types>...>::value>, |
| private __sfinae_assign_base< |
| __all<(is_copy_constructible_v<_Types> && |
| is_copy_assignable_v<_Types>)...>::value, |
| __all<(is_move_constructible_v<_Types> && |
| is_move_assignable_v<_Types>)...>::value> { |
| static_assert(0 < sizeof...(_Types), |
| "variant must consist of at least one alternative."); |
| |
| static_assert(__all<!is_array_v<_Types>...>::value, |
| "variant can not have an array type as an alternative."); |
| |
| static_assert(__all<!is_reference_v<_Types>...>::value, |
| "variant can not have a reference type as an alternative."); |
| |
| static_assert(__all<!is_void_v<_Types>...>::value, |
| "variant can not have a void type as an alternative."); |
| |
| using __first_type = variant_alternative_t<0, variant>; |
| |
| public: |
| template <bool _Dummy = true, |
| enable_if_t<__dependent_type<is_default_constructible<__first_type>, |
| _Dummy>::value, |
| int> = 0> |
| inline _LIBCPP_INLINE_VISIBILITY |
| constexpr variant() noexcept(is_nothrow_default_constructible_v<__first_type>) |
| : __impl(in_place_index<0>) {} |
| |
| variant(const variant&) = default; |
| variant(variant&&) = default; |
| |
| template < |
| class _Arg, |
| enable_if_t<!is_same_v<__uncvref_t<_Arg>, variant>, int> = 0, |
| enable_if_t<!__is_inplace_type<__uncvref_t<_Arg>>::value, int> = 0, |
| enable_if_t<!__is_inplace_index<__uncvref_t<_Arg>>::value, int> = 0, |
| class _Tp = __variant_detail::__best_match_t<_Arg, _Types...>, |
| size_t _Ip = |
| __find_detail::__find_unambiguous_index_sfinae<_Tp, _Types...>::value, |
| enable_if_t<is_constructible_v<_Tp, _Arg>, int> = 0> |
| inline _LIBCPP_INLINE_VISIBILITY |
| constexpr variant(_Arg&& __arg) noexcept( |
| is_nothrow_constructible_v<_Tp, _Arg>) |
| : __impl(in_place_index<_Ip>, _VSTD::forward<_Arg>(__arg)) {} |
| |
| template <size_t _Ip, class... _Args, |
| class = enable_if_t<(_Ip < sizeof...(_Types)), int>, |
| class _Tp = variant_alternative_t<_Ip, variant<_Types...>>, |
| enable_if_t<is_constructible_v<_Tp, _Args...>, int> = 0> |
| inline _LIBCPP_INLINE_VISIBILITY |
| explicit constexpr variant( |
| in_place_index_t<_Ip>, |
| _Args&&... __args) noexcept(is_nothrow_constructible_v<_Tp, _Args...>) |
| : __impl(in_place_index<_Ip>, _VSTD::forward<_Args>(__args)...) {} |
| |
| template < |
| size_t _Ip, |
| class _Up, |
| class... _Args, |
| enable_if_t<(_Ip < sizeof...(_Types)), int> = 0, |
| class _Tp = variant_alternative_t<_Ip, variant<_Types...>>, |
| enable_if_t<is_constructible_v<_Tp, initializer_list<_Up>&, _Args...>, |
| int> = 0> |
| inline _LIBCPP_INLINE_VISIBILITY |
| explicit constexpr variant( |
| in_place_index_t<_Ip>, |
| initializer_list<_Up> __il, |
| _Args&&... __args) noexcept( |
| is_nothrow_constructible_v<_Tp, initializer_list<_Up>&, _Args...>) |
| : __impl(in_place_index<_Ip>, __il, _VSTD::forward<_Args>(__args)...) {} |
| |
| template < |
| class _Tp, |
| class... _Args, |
| size_t _Ip = |
| __find_detail::__find_unambiguous_index_sfinae<_Tp, _Types...>::value, |
| enable_if_t<is_constructible_v<_Tp, _Args...>, int> = 0> |
| inline _LIBCPP_INLINE_VISIBILITY |
| explicit constexpr variant(in_place_type_t<_Tp>, _Args&&... __args) noexcept( |
| is_nothrow_constructible_v<_Tp, _Args...>) |
| : __impl(in_place_index<_Ip>, _VSTD::forward<_Args>(__args)...) {} |
| |
| template < |
| class _Tp, |
| class _Up, |
| class... _Args, |
| size_t _Ip = |
| __find_detail::__find_unambiguous_index_sfinae<_Tp, _Types...>::value, |
| enable_if_t<is_constructible_v<_Tp, initializer_list<_Up>&, _Args...>, |
| int> = 0> |
| inline _LIBCPP_INLINE_VISIBILITY |
| explicit constexpr variant( |
| in_place_type_t<_Tp>, |
| initializer_list<_Up> __il, |
| _Args&&... __args) noexcept( |
| is_nothrow_constructible_v<_Tp, initializer_list< _Up>&, _Args...>) |
| : __impl(in_place_index<_Ip>, __il, _VSTD::forward<_Args>(__args)...) {} |
| |
| ~variant() = default; |
| |
| variant& operator=(const variant&) = default; |
| variant& operator=(variant&&) = default; |
| |
| template < |
| class _Arg, |
| enable_if_t<!is_same_v<__uncvref_t<_Arg>, variant>, int> = 0, |
| class _Tp = __variant_detail::__best_match_t<_Arg, _Types...>, |
| size_t _Ip = |
| __find_detail::__find_unambiguous_index_sfinae<_Tp, _Types...>::value, |
| enable_if_t<is_assignable_v<_Tp&, _Arg> && is_constructible_v<_Tp, _Arg>, |
| int> = 0> |
| inline _LIBCPP_INLINE_VISIBILITY |
| variant& operator=(_Arg&& __arg) noexcept( |
| is_nothrow_assignable_v<_Tp&, _Arg> && |
| is_nothrow_constructible_v<_Tp, _Arg>) { |
| __impl.template __assign<_Ip>(_VSTD::forward<_Arg>(__arg)); |
| return *this; |
| } |
| |
| template < |
| size_t _Ip, |
| class... _Args, |
| enable_if_t<(_Ip < sizeof...(_Types)), int> = 0, |
| class _Tp = variant_alternative_t<_Ip, variant<_Types...>>, |
| enable_if_t<is_constructible_v<_Tp, _Args...>, int> = 0> |
| inline _LIBCPP_INLINE_VISIBILITY |
| _Tp& emplace(_Args&&... __args) { |
| return __impl.template __emplace<_Ip>(_VSTD::forward<_Args>(__args)...); |
| } |
| |
| template < |
| size_t _Ip, |
| class _Up, |
| class... _Args, |
| enable_if_t<(_Ip < sizeof...(_Types)), int> = 0, |
| class _Tp = variant_alternative_t<_Ip, variant<_Types...>>, |
| enable_if_t<is_constructible_v<_Tp, initializer_list<_Up>&, _Args...>, |
| int> = 0> |
| inline _LIBCPP_INLINE_VISIBILITY |
| _Tp& emplace(initializer_list<_Up> __il, _Args&&... __args) { |
| return __impl.template __emplace<_Ip>(__il, _VSTD::forward<_Args>(__args)...); |
| } |
| |
| template < |
| class _Tp, |
| class... _Args, |
| size_t _Ip = |
| __find_detail::__find_unambiguous_index_sfinae<_Tp, _Types...>::value, |
| enable_if_t<is_constructible_v<_Tp, _Args...>, int> = 0> |
| inline _LIBCPP_INLINE_VISIBILITY |
| _Tp& emplace(_Args&&... __args) { |
| return __impl.template __emplace<_Ip>(_VSTD::forward<_Args>(__args)...); |
| } |
| |
| template < |
| class _Tp, |
| class _Up, |
| class... _Args, |
| size_t _Ip = |
| __find_detail::__find_unambiguous_index_sfinae<_Tp, _Types...>::value, |
| enable_if_t<is_constructible_v<_Tp, initializer_list<_Up>&, _Args...>, |
| int> = 0> |
| inline _LIBCPP_INLINE_VISIBILITY |
| _Tp& emplace(initializer_list<_Up> __il, _Args&&... __args) { |
| return __impl.template __emplace<_Ip>(__il, _VSTD::forward<_Args>(__args)...); |
| } |
| |
| inline _LIBCPP_INLINE_VISIBILITY |
| constexpr bool valueless_by_exception() const noexcept { |
| return __impl.valueless_by_exception(); |
| } |
| |
| inline _LIBCPP_INLINE_VISIBILITY |
| constexpr size_t index() const noexcept { return __impl.index(); } |
| |
| template < |
| bool _Dummy = true, |
| enable_if_t< |
| __all<( |
| __dependent_type<is_move_constructible<_Types>, _Dummy>::value && |
| __dependent_type<is_swappable<_Types>, _Dummy>::value)...>::value, |
| int> = 0> |
| inline _LIBCPP_INLINE_VISIBILITY |
| void swap(variant& __that) noexcept( |
| __all<(is_nothrow_move_constructible_v<_Types> && |
| is_nothrow_swappable_v<_Types>)...>::value) { |
| __impl.__swap(__that.__impl); |
| } |
| |
| private: |
| __variant_detail::__impl<_Types...> __impl; |
| |
| friend struct __variant_detail::__access::__variant; |
| friend struct __variant_detail::__visitation::__variant; |
| }; |
| |
| template <size_t _Ip, class... _Types> |
| inline _LIBCPP_INLINE_VISIBILITY |
| constexpr bool __holds_alternative(const variant<_Types...>& __v) noexcept { |
| return __v.index() == _Ip; |
| } |
| |
| template <class _Tp, class... _Types> |
| inline _LIBCPP_INLINE_VISIBILITY |
| constexpr bool holds_alternative(const variant<_Types...>& __v) noexcept { |
| return __holds_alternative<__find_exactly_one_t<_Tp, _Types...>::value>(__v); |
| } |
| |
| template <size_t _Ip, class _Vp> |
| inline _LIBCPP_INLINE_VISIBILITY |
| _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS |
| constexpr auto&& __generic_get(_Vp&& __v) { |
| using __variant_detail::__access::__variant; |
| if (!__holds_alternative<_Ip>(__v)) { |
| __throw_bad_variant_access(); |
| } |
| return __variant::__get_alt<_Ip>(_VSTD::forward<_Vp>(__v)).__value; |
| } |
| |
| template <size_t _Ip, class... _Types> |
| inline _LIBCPP_INLINE_VISIBILITY |
| _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS |
| constexpr variant_alternative_t<_Ip, variant<_Types...>>& get( |
| variant<_Types...>& __v) { |
| static_assert(_Ip < sizeof...(_Types)); |
| static_assert(!is_void_v<variant_alternative_t<_Ip, variant<_Types...>>>); |
| return __generic_get<_Ip>(__v); |
| } |
| |
| template <size_t _Ip, class... _Types> |
| inline _LIBCPP_INLINE_VISIBILITY |
| _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS |
| constexpr variant_alternative_t<_Ip, variant<_Types...>>&& get( |
| variant<_Types...>&& __v) { |
| static_assert(_Ip < sizeof...(_Types)); |
| static_assert(!is_void_v<variant_alternative_t<_Ip, variant<_Types...>>>); |
| return __generic_get<_Ip>(_VSTD::move(__v)); |
| } |
| |
| template <size_t _Ip, class... _Types> |
| inline _LIBCPP_INLINE_VISIBILITY |
| _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS |
| constexpr const variant_alternative_t<_Ip, variant<_Types...>>& get( |
| const variant<_Types...>& __v) { |
| static_assert(_Ip < sizeof...(_Types)); |
| static_assert(!is_void_v<variant_alternative_t<_Ip, variant<_Types...>>>); |
| return __generic_get<_Ip>(__v); |
| } |
| |
| template <size_t _Ip, class... _Types> |
| inline _LIBCPP_INLINE_VISIBILITY |
| _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS |
| constexpr const variant_alternative_t<_Ip, variant<_Types...>>&& get( |
| const variant<_Types...>&& __v) { |
| static_assert(_Ip < sizeof...(_Types)); |
| static_assert(!is_void_v<variant_alternative_t<_Ip, variant<_Types...>>>); |
| return __generic_get<_Ip>(_VSTD::move(__v)); |
| } |
| |
| template <class _Tp, class... _Types> |
| inline _LIBCPP_INLINE_VISIBILITY |
| _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS |
| constexpr _Tp& get(variant<_Types...>& __v) { |
| static_assert(!is_void_v<_Tp>); |
| return _VSTD::get<__find_exactly_one_t<_Tp, _Types...>::value>(__v); |
| } |
| |
| template <class _Tp, class... _Types> |
| inline _LIBCPP_INLINE_VISIBILITY |
| _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS |
| constexpr _Tp&& get(variant<_Types...>&& __v) { |
| static_assert(!is_void_v<_Tp>); |
| return _VSTD::get<__find_exactly_one_t<_Tp, _Types...>::value>( |
| _VSTD::move(__v)); |
| } |
| |
| template <class _Tp, class... _Types> |
| inline _LIBCPP_INLINE_VISIBILITY |
| _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS |
| constexpr const _Tp& get(const variant<_Types...>& __v) { |
| static_assert(!is_void_v<_Tp>); |
| return _VSTD::get<__find_exactly_one_t<_Tp, _Types...>::value>(__v); |
| } |
| |
| template <class _Tp, class... _Types> |
| inline _LIBCPP_INLINE_VISIBILITY |
| _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS |
| constexpr const _Tp&& get(const variant<_Types...>&& __v) { |
| static_assert(!is_void_v<_Tp>); |
| return _VSTD::get<__find_exactly_one_t<_Tp, _Types...>::value>( |
| _VSTD::move(__v)); |
| } |
| |
| template <size_t _Ip, class _Vp> |
| inline _LIBCPP_INLINE_VISIBILITY |
| constexpr auto* __generic_get_if(_Vp* __v) noexcept { |
| using __variant_detail::__access::__variant; |
| return __v && __holds_alternative<_Ip>(*__v) |
| ? _VSTD::addressof(__variant::__get_alt<_Ip>(*__v).__value) |
| : nullptr; |
| } |
| |
| template <size_t _Ip, class... _Types> |
| inline _LIBCPP_INLINE_VISIBILITY |
| constexpr add_pointer_t<variant_alternative_t<_Ip, variant<_Types...>>> |
| get_if(variant<_Types...>* __v) noexcept { |
| static_assert(_Ip < sizeof...(_Types)); |
| static_assert(!is_void_v<variant_alternative_t<_Ip, variant<_Types...>>>); |
| return __generic_get_if<_Ip>(__v); |
| } |
| |
| template <size_t _Ip, class... _Types> |
| inline _LIBCPP_INLINE_VISIBILITY |
| constexpr add_pointer_t<const variant_alternative_t<_Ip, variant<_Types...>>> |
| get_if(const variant<_Types...>* __v) noexcept { |
| static_assert(_Ip < sizeof...(_Types)); |
| static_assert(!is_void_v<variant_alternative_t<_Ip, variant<_Types...>>>); |
| return __generic_get_if<_Ip>(__v); |
| } |
| |
| template <class _Tp, class... _Types> |
| inline _LIBCPP_INLINE_VISIBILITY |
| constexpr add_pointer_t<_Tp> |
| get_if(variant<_Types...>* __v) noexcept { |
| static_assert(!is_void_v<_Tp>); |
| return _VSTD::get_if<__find_exactly_one_t<_Tp, _Types...>::value>(__v); |
| } |
| |
| template <class _Tp, class... _Types> |
| inline _LIBCPP_INLINE_VISIBILITY |
| constexpr add_pointer_t<const _Tp> |
| get_if(const variant<_Types...>* __v) noexcept { |
| static_assert(!is_void_v<_Tp>); |
| return _VSTD::get_if<__find_exactly_one_t<_Tp, _Types...>::value>(__v); |
| } |
| |
| template <class _Operator> |
| struct __convert_to_bool { |
| template <class _T1, class _T2> |
| _LIBCPP_INLINE_VISIBILITY constexpr bool operator()(_T1 && __t1, _T2&& __t2) const { |
| static_assert(std::is_convertible<decltype(_Operator{}(_VSTD::forward<_T1>(__t1), _VSTD::forward<_T2>(__t2))), bool>::value, |
| "the relational operator does not return a type which is implicitly convertible to bool"); |
| return _Operator{}(_VSTD::forward<_T1>(__t1), _VSTD::forward<_T2>(__t2)); |
| } |
| }; |
| |
| template <class... _Types> |
| inline _LIBCPP_INLINE_VISIBILITY |
| constexpr bool operator==(const variant<_Types...>& __lhs, |
| const variant<_Types...>& __rhs) { |
| using __variant_detail::__visitation::__variant; |
| if (__lhs.index() != __rhs.index()) return false; |
| if (__lhs.valueless_by_exception()) return true; |
| return __variant::__visit_value_at(__lhs.index(), __convert_to_bool<equal_to<>>{}, __lhs, __rhs); |
| } |
| |
| template <class... _Types> |
| inline _LIBCPP_INLINE_VISIBILITY |
| constexpr bool operator!=(const variant<_Types...>& __lhs, |
| const variant<_Types...>& __rhs) { |
| using __variant_detail::__visitation::__variant; |
| if (__lhs.index() != __rhs.index()) return true; |
| if (__lhs.valueless_by_exception()) return false; |
| return __variant::__visit_value_at( |
| __lhs.index(), __convert_to_bool<not_equal_to<>>{}, __lhs, __rhs); |
| } |
| |
| template <class... _Types> |
| inline _LIBCPP_INLINE_VISIBILITY |
| constexpr bool operator<(const variant<_Types...>& __lhs, |
| const variant<_Types...>& __rhs) { |
| using __variant_detail::__visitation::__variant; |
| if (__rhs.valueless_by_exception()) return false; |
| if (__lhs.valueless_by_exception()) return true; |
| if (__lhs.index() < __rhs.index()) return true; |
| if (__lhs.index() > __rhs.index()) return false; |
| return __variant::__visit_value_at(__lhs.index(), __convert_to_bool<less<>>{}, __lhs, __rhs); |
| } |
| |
| template <class... _Types> |
| inline _LIBCPP_INLINE_VISIBILITY |
| constexpr bool operator>(const variant<_Types...>& __lhs, |
| const variant<_Types...>& __rhs) { |
| using __variant_detail::__visitation::__variant; |
| if (__lhs.valueless_by_exception()) return false; |
| if (__rhs.valueless_by_exception()) return true; |
| if (__lhs.index() > __rhs.index()) return true; |
| if (__lhs.index() < __rhs.index()) return false; |
| return __variant::__visit_value_at(__lhs.index(), __convert_to_bool<greater<>>{}, __lhs, __rhs); |
| } |
| |
| template <class... _Types> |
| inline _LIBCPP_INLINE_VISIBILITY |
| constexpr bool operator<=(const variant<_Types...>& __lhs, |
| const variant<_Types...>& __rhs) { |
| using __variant_detail::__visitation::__variant; |
| if (__lhs.valueless_by_exception()) return true; |
| if (__rhs.valueless_by_exception()) return false; |
| if (__lhs.index() < __rhs.index()) return true; |
| if (__lhs.index() > __rhs.index()) return false; |
| return __variant::__visit_value_at( |
| __lhs.index(), __convert_to_bool<less_equal<>>{}, __lhs, __rhs); |
| } |
| |
| template <class... _Types> |
| inline _LIBCPP_INLINE_VISIBILITY |
| constexpr bool operator>=(const variant<_Types...>& __lhs, |
| const variant<_Types...>& __rhs) { |
| using __variant_detail::__visitation::__variant; |
| if (__rhs.valueless_by_exception()) return true; |
| if (__lhs.valueless_by_exception()) return false; |
| if (__lhs.index() > __rhs.index()) return true; |
| if (__lhs.index() < __rhs.index()) return false; |
| return __variant::__visit_value_at( |
| __lhs.index(), __convert_to_bool<greater_equal<>>{}, __lhs, __rhs); |
| } |
| |
| template <class _Visitor, class... _Vs> |
| inline _LIBCPP_INLINE_VISIBILITY |
| _LIBCPP_AVAILABILITY_THROW_BAD_VARIANT_ACCESS |
| constexpr decltype(auto) visit(_Visitor&& __visitor, _Vs&&... __vs) { |
| using __variant_detail::__visitation::__variant; |
| bool __results[] = {__vs.valueless_by_exception()...}; |
| for (bool __result : __results) { |
| if (__result) { |
| __throw_bad_variant_access(); |
| } |
| } |
| return __variant::__visit_value(_VSTD::forward<_Visitor>(__visitor), |
| _VSTD::forward<_Vs>(__vs)...); |
| } |
| |
| struct _LIBCPP_TEMPLATE_VIS monostate {}; |
| |
| inline _LIBCPP_INLINE_VISIBILITY |
| constexpr bool operator<(monostate, monostate) noexcept { return false; } |
| |
| inline _LIBCPP_INLINE_VISIBILITY |
| constexpr bool operator>(monostate, monostate) noexcept { return false; } |
| |
| inline _LIBCPP_INLINE_VISIBILITY |
| constexpr bool operator<=(monostate, monostate) noexcept { return true; } |
| |
| inline _LIBCPP_INLINE_VISIBILITY |
| constexpr bool operator>=(monostate, monostate) noexcept { return true; } |
| |
| inline _LIBCPP_INLINE_VISIBILITY |
| constexpr bool operator==(monostate, monostate) noexcept { return true; } |
| |
| inline _LIBCPP_INLINE_VISIBILITY |
| constexpr bool operator!=(monostate, monostate) noexcept { return false; } |
| |
| template <class... _Types> |
| inline _LIBCPP_INLINE_VISIBILITY |
| auto swap(variant<_Types...>& __lhs, |
| variant<_Types...>& __rhs) noexcept(noexcept(__lhs.swap(__rhs))) |
| -> decltype(__lhs.swap(__rhs)) { |
| __lhs.swap(__rhs); |
| } |
| |
| template <class... _Types> |
| struct _LIBCPP_TEMPLATE_VIS hash< |
| __enable_hash_helper<variant<_Types...>, remove_const_t<_Types>...>> { |
| using argument_type = variant<_Types...>; |
| using result_type = size_t; |
| |
| inline _LIBCPP_INLINE_VISIBILITY |
| result_type operator()(const argument_type& __v) const { |
| using __variant_detail::__visitation::__variant; |
| size_t __res = |
| __v.valueless_by_exception() |
| ? 299792458 // Random value chosen by the universe upon creation |
| : __variant::__visit_alt( |
| [](const auto& __alt) { |
| using __alt_type = __uncvref_t<decltype(__alt)>; |
| using __value_type = remove_const_t< |
| typename __alt_type::__value_type>; |
| return hash<__value_type>{}(__alt.__value); |
| }, |
| __v); |
| return __hash_combine(__res, hash<size_t>{}(__v.index())); |
| } |
| }; |
| |
| template <> |
| struct _LIBCPP_TEMPLATE_VIS hash<monostate> { |
| using argument_type = monostate; |
| using result_type = size_t; |
| |
| inline _LIBCPP_INLINE_VISIBILITY |
| result_type operator()(const argument_type&) const _NOEXCEPT { |
| return 66740831; // return a fundamentally attractive random value. |
| } |
| }; |
| |
| #endif // _LIBCPP_STD_VER > 14 |
| |
| _LIBCPP_END_NAMESPACE_STD |
| |
| _LIBCPP_POP_MACROS |
| |
| #endif // _LIBCPP_VARIANT |
