29 #ifndef _GLIBCXX_VARIANT
30 #define _GLIBCXX_VARIANT 1
32 #pragma GCC system_header
34 #if __cplusplus >= 201703L
36 #include <type_traits>
48 #if __cplusplus > 201703L
52 namespace std _GLIBCXX_VISIBILITY(default)
54 _GLIBCXX_BEGIN_NAMESPACE_VERSION
60 template<
size_t _Np,
typename... _Types>
63 template<
size_t _Np,
typename _First,
typename... _Rest>
64 struct _Nth_type<_Np, _First, _Rest...>
65 : _Nth_type<_Np-1, _Rest...> { };
67 template<
typename _First,
typename... _Rest>
68 struct _Nth_type<0, _First, _Rest...>
69 {
using type = _First; };
74 #define __cpp_lib_variant 201606L
76 template<
typename... _Types>
class tuple;
77 template<
typename... _Types>
class variant;
78 template <
typename>
struct hash;
80 template<
typename _Variant>
83 template<
typename _Variant>
84 struct variant_size<const _Variant> : variant_size<_Variant> {};
86 template<
typename _Variant>
87 struct variant_size<volatile _Variant> : variant_size<_Variant> {};
89 template<
typename _Variant>
90 struct variant_size<const volatile _Variant> : variant_size<_Variant> {};
92 template<
typename... _Types>
93 struct variant_size<variant<_Types...>>
96 template<
typename _Variant>
97 inline constexpr
size_t variant_size_v = variant_size<_Variant>::value;
99 template<
size_t _Np,
typename _Variant>
100 struct variant_alternative;
102 template<
size_t _Np,
typename _First,
typename... _Rest>
103 struct variant_alternative<_Np, variant<_First, _Rest...>>
104 : variant_alternative<_Np-1, variant<_Rest...>> {};
106 template<
typename _First,
typename... _Rest>
107 struct variant_alternative<0, variant<_First, _Rest...>>
108 {
using type = _First; };
110 template<
size_t _Np,
typename _Variant>
111 using variant_alternative_t =
112 typename variant_alternative<_Np, _Variant>::type;
114 template<
size_t _Np,
typename _Variant>
115 struct variant_alternative<_Np, const _Variant>
116 {
using type = add_const_t<variant_alternative_t<_Np, _Variant>>; };
118 template<
size_t _Np,
typename _Variant>
119 struct variant_alternative<_Np, volatile _Variant>
120 {
using type = add_volatile_t<variant_alternative_t<_Np, _Variant>>; };
122 template<
size_t _Np,
typename _Variant>
123 struct variant_alternative<_Np, const volatile _Variant>
124 {
using type = add_cv_t<variant_alternative_t<_Np, _Variant>>; };
126 inline constexpr
size_t variant_npos = -1;
128 template<
size_t _Np,
typename... _Types>
129 constexpr variant_alternative_t<_Np, variant<_Types...>>&
130 get(variant<_Types...>&);
132 template<
size_t _Np,
typename... _Types>
133 constexpr variant_alternative_t<_Np, variant<_Types...>>&&
134 get(variant<_Types...>&&);
136 template<
size_t _Np,
typename... _Types>
137 constexpr variant_alternative_t<_Np, variant<_Types...>>
const&
138 get(
const variant<_Types...>&);
140 template<
size_t _Np,
typename... _Types>
141 constexpr variant_alternative_t<_Np, variant<_Types...>>
const&&
142 get(
const variant<_Types...>&&);
144 template<
typename _Result_type,
typename _Visitor,
typename... _Variants>
145 constexpr decltype(
auto)
146 __do_visit(_Visitor&& __visitor, _Variants&&... __variants);
148 template <typename... _Types, typename _Tp>
150 __variant_cast(_Tp&& __rhs)
152 if constexpr (is_lvalue_reference_v<_Tp>)
154 if constexpr (is_const_v<remove_reference_t<_Tp>>)
155 return static_cast<const variant<_Types...>&>(__rhs);
157 return static_cast<variant<_Types...>&>(__rhs);
160 return static_cast<variant<_Types...>&&>(__rhs);
169 template<
typename _Tp,
typename... _Types>
172 template<
typename _Tp,
typename... _Types>
173 inline constexpr
size_t __index_of_v = __index_of<_Tp, _Types...>::value;
175 template<
typename _Tp,
typename _First,
typename... _Rest>
176 struct __index_of<_Tp, _First, _Rest...> :
178 ? 0 : __index_of_v<_Tp, _Rest...> + 1> {};
181 struct __variant_cookie {};
183 struct __variant_idx_cookie {
using type = __variant_idx_cookie; };
185 template<
typename>
struct __deduce_visit_result { };
188 template<
typename _Visitor,
typename... _Variants>
190 __raw_visit(_Visitor&& __visitor, _Variants&&... __variants)
192 std::__do_visit<__variant_cookie>(std::forward<_Visitor>(__visitor),
193 std::forward<_Variants>(__variants)...);
197 template<
typename _Visitor,
typename... _Variants>
199 __raw_idx_visit(_Visitor&& __visitor, _Variants&&... __variants)
201 std::__do_visit<__variant_idx_cookie>(std::forward<_Visitor>(__visitor),
202 std::forward<_Variants>(__variants)...);
207 template<
typename _Type,
bool = std::is_trivially_destructible_v<_Type>>
208 struct _Uninitialized;
210 template<
typename _Type>
211 struct _Uninitialized<_Type, true>
213 template<
typename... _Args>
215 _Uninitialized(in_place_index_t<0>, _Args&&... __args)
219 constexpr
const _Type& _M_get() const & noexcept
220 {
return _M_storage; }
222 constexpr _Type& _M_get() & noexcept
223 {
return _M_storage; }
225 constexpr
const _Type&& _M_get() const && noexcept
228 constexpr _Type&& _M_get() && noexcept
234 template<
typename _Type>
235 struct _Uninitialized<_Type, false>
237 template<
typename... _Args>
239 _Uninitialized(in_place_index_t<0>, _Args&&... __args)
242 _Type(std::forward<_Args>(__args)...);
245 const _Type& _M_get() const & noexcept
246 {
return *_M_storage._M_ptr(); }
248 _Type& _M_get() & noexcept
249 {
return *_M_storage._M_ptr(); }
251 const _Type&& _M_get() const && noexcept
252 {
return std::move(*_M_storage._M_ptr()); }
254 _Type&& _M_get() && noexcept
255 {
return std::move(*_M_storage._M_ptr()); }
257 __gnu_cxx::__aligned_membuf<_Type> _M_storage;
260 template<
typename _Union>
261 constexpr decltype(
auto)
262 __get(in_place_index_t<0>, _Union&& __u) noexcept
263 {
return std::forward<_Union>(__u)._M_first._M_get(); }
265 template<
size_t _Np,
typename _Union>
266 constexpr decltype(
auto)
267 __get(in_place_index_t<_Np>, _Union&& __u) noexcept
269 return __variant::__get(in_place_index<_Np-1>,
270 std::forward<_Union>(__u)._M_rest);
274 template<
size_t _Np,
typename _Variant>
275 constexpr decltype(
auto)
276 __get(_Variant&& __v) noexcept
278 return __variant::__get(std::in_place_index<_Np>,
279 std::forward<_Variant>(__v)._M_u);
282 template<
typename... _Types>
285 static constexpr
bool _S_default_ctor =
286 is_default_constructible_v<
typename _Nth_type<0, _Types...>::type>;
287 static constexpr
bool _S_copy_ctor =
288 (is_copy_constructible_v<_Types> && ...);
289 static constexpr
bool _S_move_ctor =
290 (is_move_constructible_v<_Types> && ...);
291 static constexpr
bool _S_copy_assign =
293 && (is_copy_assignable_v<_Types> && ...);
294 static constexpr
bool _S_move_assign =
296 && (is_move_assignable_v<_Types> && ...);
298 static constexpr
bool _S_trivial_dtor =
299 (is_trivially_destructible_v<_Types> && ...);
300 static constexpr
bool _S_trivial_copy_ctor =
301 (is_trivially_copy_constructible_v<_Types> && ...);
302 static constexpr
bool _S_trivial_move_ctor =
303 (is_trivially_move_constructible_v<_Types> && ...);
304 static constexpr
bool _S_trivial_copy_assign =
305 _S_trivial_dtor && _S_trivial_copy_ctor
306 && (is_trivially_copy_assignable_v<_Types> && ...);
307 static constexpr
bool _S_trivial_move_assign =
308 _S_trivial_dtor && _S_trivial_move_ctor
309 && (is_trivially_move_assignable_v<_Types> && ...);
313 static constexpr
bool _S_nothrow_default_ctor =
314 is_nothrow_default_constructible_v<
315 typename _Nth_type<0, _Types...>::type>;
316 static constexpr
bool _S_nothrow_copy_ctor =
false;
317 static constexpr
bool _S_nothrow_move_ctor =
318 (is_nothrow_move_constructible_v<_Types> && ...);
319 static constexpr
bool _S_nothrow_copy_assign =
false;
320 static constexpr
bool _S_nothrow_move_assign =
322 && (is_nothrow_move_assignable_v<_Types> && ...);
326 template<
typename... _Types>
327 union _Variadic_union { };
329 template<
typename _First,
typename... _Rest>
330 union _Variadic_union<_First, _Rest...>
332 constexpr _Variadic_union() : _M_rest() { }
334 template<
typename... _Args>
335 constexpr _Variadic_union(in_place_index_t<0>, _Args&&... __args)
336 : _M_first(in_place_index<0>,
std::
forward<_Args>(__args)...)
339 template<
size_t _Np,
typename... _Args>
340 constexpr _Variadic_union(in_place_index_t<_Np>, _Args&&... __args)
341 : _M_rest(in_place_index<_Np-1>,
std::
forward<_Args>(__args)...)
344 _Uninitialized<_First> _M_first;
345 _Variadic_union<_Rest...> _M_rest;
353 template<
typename _Tp>
354 struct _Never_valueless_alt
355 : __and_<bool_constant<sizeof(_Tp) <= 256>, is_trivially_copyable<_Tp>>
368 template <typename... _Types>
369 constexpr bool __never_valueless()
371 return _Traits<_Types...>::_S_move_assign
372 && (_Never_valueless_alt<_Types>::value && ...);
376 template<bool __trivially_destructible, typename... _Types>
377 struct _Variant_storage;
379 template <typename... _Types>
380 using __select_index =
381 typename __select_int::_Select_int_base<sizeof...(_Types),
383 unsigned short>::type::value_type;
385 template<typename... _Types>
386 struct _Variant_storage<false, _Types...>
390 : _M_index(static_cast<__index_type>(variant_npos))
393 template<size_t _Np, typename... _Args>
395 _Variant_storage(in_place_index_t<_Np>, _Args&&... __args)
396 : _M_u(in_place_index<_Np>, std::forward<_Args>(__args)...),
402 if (!_M_valid()) [[unlikely]]
405 std::__do_visit<void>([](auto&& __this_mem) mutable
407 std::_Destroy(std::__addressof(__this_mem));
408 }, __variant_cast<_Types...>(*this));
410 _M_index = static_cast<__index_type>(variant_npos);
417 _M_storage() const noexcept
419 return const_cast<void*>(static_cast<const void*>(
420 std::addressof(_M_u)));
424 _M_valid() const noexcept
426 if constexpr (__variant::__never_valueless<_Types...>())
428 return this->_M_index != __index_type(variant_npos);
431 _Variadic_union<_Types...> _M_u;
432 using __index_type = __select_index<_Types...>;
433 __index_type _M_index;
436 template<typename... _Types>
437 struct _Variant_storage<true, _Types...>
441 : _M_index(static_cast<__index_type>(variant_npos))
444 template<
size_t _Np,
typename... _Args>
446 _Variant_storage(in_place_index_t<_Np>, _Args&&... __args)
447 : _M_u(in_place_index<_Np>,
std::
forward<_Args>(__args)...),
451 void _M_reset() noexcept
452 { _M_index =
static_cast<__index_type
>(variant_npos); }
455 _M_storage() const noexcept
457 return const_cast<void*
>(
static_cast<const void*
>(
462 _M_valid() const noexcept
464 if constexpr (__variant::__never_valueless<_Types...>())
466 return this->_M_index != static_cast<__index_type>(variant_npos);
469 _Variadic_union<_Types...> _M_u;
470 using __index_type = __select_index<_Types...>;
471 __index_type _M_index;
474 template<typename... _Types>
475 using _Variant_storage_alias =
476 _Variant_storage<_Traits<_Types...>::_S_trivial_dtor, _Types...>;
478 template<typename _Tp, typename _Up>
479 void __variant_construct_single(_Tp&& __lhs, _Up&& __rhs_mem)
483 if constexpr (!is_same_v<_Type, __variant_cookie>)
485 _Type(
std::
forward<decltype(__rhs_mem)>(__rhs_mem));
488 template<
typename... _Types,
typename _Tp,
typename _Up>
489 void __variant_construct(_Tp&& __lhs, _Up&& __rhs)
491 __lhs._M_index = __rhs._M_index;
492 __variant::__raw_visit([&__lhs](
auto&& __rhs_mem)
mutable
494 __variant_construct_single(std::forward<_Tp>(__lhs),
496 }, __variant_cast<_Types...>(std::forward<_Up>(__rhs)));
502 template<bool,
typename... _Types>
503 struct _Copy_ctor_base : _Variant_storage_alias<_Types...>
505 using _Base = _Variant_storage_alias<_Types...>;
508 _Copy_ctor_base(
const _Copy_ctor_base& __rhs)
509 noexcept(_Traits<_Types...>::_S_nothrow_copy_ctor)
511 __variant_construct<_Types...>(*
this, __rhs);
514 _Copy_ctor_base(_Copy_ctor_base&&) =
default;
515 _Copy_ctor_base& operator=(
const _Copy_ctor_base&) =
default;
516 _Copy_ctor_base& operator=(_Copy_ctor_base&&) =
default;
519 template<
typename... _Types>
520 struct _Copy_ctor_base<true, _Types...> : _Variant_storage_alias<_Types...>
522 using _Base = _Variant_storage_alias<_Types...>;
526 template<
typename... _Types>
527 using _Copy_ctor_alias =
528 _Copy_ctor_base<_Traits<_Types...>::_S_trivial_copy_ctor, _Types...>;
530 template<bool,
typename... _Types>
531 struct _Move_ctor_base : _Copy_ctor_alias<_Types...>
533 using _Base = _Copy_ctor_alias<_Types...>;
536 _Move_ctor_base(_Move_ctor_base&& __rhs)
537 noexcept(_Traits<_Types...>::_S_nothrow_move_ctor)
539 __variant_construct<_Types...>(*
this,
std::move(__rhs));
542 template<
typename _Up>
543 void _M_destructive_move(
unsigned short __rhs_index, _Up&& __rhs)
546 __variant_construct_single(*
this, std::forward<_Up>(__rhs));
547 this->_M_index = __rhs_index;
550 template<
typename _Up>
551 void _M_destructive_copy(
unsigned short __rhs_index,
const _Up& __rhs)
554 __variant_construct_single(*
this, __rhs);
555 this->_M_index = __rhs_index;
558 _Move_ctor_base(
const _Move_ctor_base&) =
default;
559 _Move_ctor_base& operator=(
const _Move_ctor_base&) =
default;
560 _Move_ctor_base& operator=(_Move_ctor_base&&) =
default;
563 template<
typename... _Types>
564 struct _Move_ctor_base<true, _Types...> : _Copy_ctor_alias<_Types...>
566 using _Base = _Copy_ctor_alias<_Types...>;
569 template<
typename _Up>
570 void _M_destructive_move(
unsigned short __rhs_index, _Up&& __rhs)
573 __variant_construct_single(*
this, std::forward<_Up>(__rhs));
574 this->_M_index = __rhs_index;
577 template<
typename _Up>
578 void _M_destructive_copy(
unsigned short __rhs_index,
const _Up& __rhs)
581 __variant_construct_single(*
this, __rhs);
582 this->_M_index = __rhs_index;
586 template<
typename... _Types>
587 using _Move_ctor_alias =
588 _Move_ctor_base<_Traits<_Types...>::_S_trivial_move_ctor, _Types...>;
590 template<bool,
typename... _Types>
591 struct _Copy_assign_base : _Move_ctor_alias<_Types...>
593 using _Base = _Move_ctor_alias<_Types...>;
597 operator=(
const _Copy_assign_base& __rhs)
598 noexcept(_Traits<_Types...>::_S_nothrow_copy_assign)
600 __variant::__raw_idx_visit(
601 [
this](
auto&& __rhs_mem,
auto __rhs_index)
mutable
603 if constexpr (__rhs_index != variant_npos)
605 if (this->_M_index == __rhs_index)
606 __variant::__get<__rhs_index>(*
this) = __rhs_mem;
609 using __rhs_type = __remove_cvref_t<decltype(__rhs_mem)>;
610 if constexpr (is_nothrow_copy_constructible_v<__rhs_type>
611 || !is_nothrow_move_constructible_v<__rhs_type>)
619 this->_M_destructive_copy(__rhs_index, __rhs_mem);
621 __variant_cast<_Types...>(*this)
622 = variant<_Types...>(std::in_place_index<__rhs_index>,
628 }, __variant_cast<_Types...>(__rhs));
632 _Copy_assign_base(
const _Copy_assign_base&) =
default;
633 _Copy_assign_base(_Copy_assign_base&&) =
default;
634 _Copy_assign_base& operator=(_Copy_assign_base&&) =
default;
637 template<
typename... _Types>
638 struct _Copy_assign_base<true, _Types...> : _Move_ctor_alias<_Types...>
640 using _Base = _Move_ctor_alias<_Types...>;
644 template<
typename... _Types>
645 using _Copy_assign_alias =
646 _Copy_assign_base<_Traits<_Types...>::_S_trivial_copy_assign, _Types...>;
648 template<bool,
typename... _Types>
649 struct _Move_assign_base : _Copy_assign_alias<_Types...>
651 using _Base = _Copy_assign_alias<_Types...>;
655 operator=(_Move_assign_base&& __rhs)
656 noexcept(_Traits<_Types...>::_S_nothrow_move_assign)
658 __variant::__raw_idx_visit(
659 [
this](
auto&& __rhs_mem,
auto __rhs_index)
mutable
661 if constexpr (__rhs_index != variant_npos)
663 if (this->_M_index == __rhs_index)
664 __variant::__get<__rhs_index>(*
this) =
std::move(__rhs_mem);
666 __variant_cast<_Types...>(*this)
667 .template emplace<__rhs_index>(
std::move(__rhs_mem));
671 }, __variant_cast<_Types...>(__rhs));
675 _Move_assign_base(
const _Move_assign_base&) =
default;
676 _Move_assign_base(_Move_assign_base&&) =
default;
677 _Move_assign_base& operator=(
const _Move_assign_base&) =
default;
680 template<
typename... _Types>
681 struct _Move_assign_base<true, _Types...> : _Copy_assign_alias<_Types...>
683 using _Base = _Copy_assign_alias<_Types...>;
687 template<
typename... _Types>
688 using _Move_assign_alias =
689 _Move_assign_base<_Traits<_Types...>::_S_trivial_move_assign, _Types...>;
691 template<
typename... _Types>
692 struct _Variant_base : _Move_assign_alias<_Types...>
694 using _Base = _Move_assign_alias<_Types...>;
698 noexcept(_Traits<_Types...>::_S_nothrow_default_ctor)
699 : _Variant_base(in_place_index<0>) { }
701 template<
size_t _Np,
typename... _Args>
703 _Variant_base(in_place_index_t<_Np> __i, _Args&&... __args)
707 _Variant_base(
const _Variant_base&) =
default;
708 _Variant_base(_Variant_base&&) =
default;
709 _Variant_base& operator=(
const _Variant_base&) =
default;
710 _Variant_base& operator=(_Variant_base&&) =
default;
714 template<
typename _Tp,
typename _Tuple>
715 struct __tuple_count;
717 template<
typename _Tp,
typename _Tuple>
718 inline constexpr
size_t __tuple_count_v =
719 __tuple_count<_Tp, _Tuple>::value;
721 template<
typename _Tp,
typename... _Types>
722 struct __tuple_count<_Tp, tuple<_Types...>>
723 : integral_constant<size_t, 0> { };
725 template<
typename _Tp,
typename _First,
typename... _Rest>
726 struct __tuple_count<_Tp, tuple<_First, _Rest...>>
729 __tuple_count_v<_Tp, tuple<_Rest...>> + is_same_v<_Tp, _First>> { };
732 template<
typename _Tp,
typename... _Types>
733 inline constexpr
bool __exactly_once =
734 __tuple_count_v<_Tp, tuple<_Types...>> == 1;
737 template<
typename _Ti>
struct _Arr { _Ti _M_x[1]; };
740 template<
size_t _Ind,
typename _Tp,
typename _Ti,
741 bool _Ti_is_cv_bool = is_same_v<remove_cv_t<_Ti>,
bool>,
751 template<
size_t _Ind,
typename _Tp,
typename _Ti>
752 struct _Build_FUN<_Ind, _Tp, _Ti, false,
753 void_t<decltype(_Arr<_Ti>{{std::declval<_Tp>()}})>>
756 static integral_constant<size_t, _Ind> _S_fun(_Ti);
760 template<
size_t _Ind,
typename _Tp,
typename _Ti>
761 struct _Build_FUN<_Ind, _Tp, _Ti, true,
762 enable_if_t<is_same_v<__remove_cvref_t<_Tp>, bool>>>
765 static integral_constant<size_t, _Ind> _S_fun(_Ti);
768 template<
typename _Tp,
typename _Variant,
769 typename = make_index_sequence<variant_size_v<_Variant>>>
772 template<
typename _Tp,
typename... _Ti,
size_t... _Ind>
774 : _Build_FUN<_Ind, _Tp, _Ti>...
776 using _Build_FUN<_Ind, _Tp, _Ti>::_S_fun...;
781 template<
typename _Tp,
typename _Variant>
783 = decltype(_Build_FUNs<_Tp, _Variant>::_S_fun(std::declval<_Tp>()));
786 template<
typename _Tp,
typename _Variant,
typename =
void>
787 struct __accepted_index
788 : integral_constant<size_t, variant_npos>
791 template<
typename _Tp,
typename _Variant>
792 struct __accepted_index<_Tp, _Variant,
void_t<_FUN_type<_Tp, _Variant>>>
793 : _FUN_type<_Tp, _Variant>
797 template<
typename _Variant>
798 void* __get_storage(_Variant&& __v) noexcept
799 {
return __v._M_storage(); }
801 template <
typename _Maybe_variant_cookie,
typename _Variant>
802 struct _Extra_visit_slot_needed
804 template <
typename>
struct _Variant_never_valueless;
806 template <
typename... _Types>
807 struct _Variant_never_valueless<variant<_Types...>>
808 : bool_constant<__variant::__never_valueless<_Types...>()> {};
810 static constexpr
bool value =
811 (is_same_v<_Maybe_variant_cookie, __variant_cookie>
812 || is_same_v<_Maybe_variant_cookie, __variant_idx_cookie>)
813 && !_Variant_never_valueless<__remove_cvref_t<_Variant>>::value;
817 template<
typename _Tp,
size_t... _Dimensions>
821 template<
typename _Tp>
822 struct _Multi_array<_Tp>
825 struct __untag_result
827 {
using element_type = _Tp; };
829 template <
typename... _Args>
830 struct __untag_result<const void(*)(_Args...)>
832 {
using element_type = void(*)(_Args...); };
834 template <
typename... _Args>
835 struct __untag_result<__variant_cookie(*)(_Args...)>
837 {
using element_type = void(*)(_Args...); };
839 template <
typename... _Args>
840 struct __untag_result<__variant_idx_cookie(*)(_Args...)>
842 {
using element_type = void(*)(_Args...); };
844 template <
typename _Res,
typename... _Args>
845 struct __untag_result<__deduce_visit_result<_Res>(*)(_Args...)>
847 {
using element_type = _Res(*)(_Args...); };
849 using __result_is_deduced = __untag_result<_Tp>;
851 constexpr
const typename __untag_result<_Tp>::element_type&
855 typename __untag_result<_Tp>::element_type _M_data;
859 template<
typename _Ret,
861 typename... _Variants,
862 size_t __first,
size_t... __rest>
863 struct _Multi_array<_Ret(*)(_Visitor, _Variants...), __first, __rest...>
865 static constexpr
size_t __index =
866 sizeof...(_Variants) -
sizeof...(__rest) - 1;
868 using _Variant =
typename _Nth_type<__index, _Variants...>::type;
870 static constexpr
int __do_cookie =
871 _Extra_visit_slot_needed<_Ret, _Variant>::value ? 1 : 0;
873 using _Tp = _Ret(*)(_Visitor, _Variants...);
875 template<
typename... _Args>
876 constexpr decltype(
auto)
877 _M_access(
size_t __first_index, _Args... __rest_indices)
const
879 return _M_arr[__first_index + __do_cookie]
880 ._M_access(__rest_indices...);
883 _Multi_array<_Tp, __rest...> _M_arr[__first + __do_cookie];
913 template<
typename _Array_type,
typename _Index_seq>
914 struct __gen_vtable_impl;
923 template<
typename _Result_type,
typename _Visitor,
size_t... __dimensions,
924 typename... _Variants,
size_t... __indices>
925 struct __gen_vtable_impl<
926 _Multi_array<_Result_type (*)(_Visitor, _Variants...), __dimensions...>,
931 _Variants...>::type>;
933 _Multi_array<_Result_type (*)(_Visitor, _Variants...),
936 static constexpr _Array_type
939 _Array_type __vtable{};
945 template<
size_t... __var_indices>
946 static constexpr
void
947 _S_apply_all_alts(_Array_type& __vtable,
950 if constexpr (_Extra_visit_slot_needed<_Result_type, _Next>::value)
951 (_S_apply_single_alt<true, __var_indices>(
952 __vtable._M_arr[__var_indices + 1],
953 &(__vtable._M_arr[0])), ...);
955 (_S_apply_single_alt<false, __var_indices>(
956 __vtable._M_arr[__var_indices]), ...);
959 template<
bool __do_cookie,
size_t __index,
typename _Tp>
960 static constexpr
void
961 _S_apply_single_alt(_Tp& __element, _Tp* __cookie_element =
nullptr)
963 if constexpr (__do_cookie)
965 __element = __gen_vtable_impl<
968 *__cookie_element = __gen_vtable_impl<
974 __element = __gen_vtable_impl<
984 template<
typename _Result_type,
typename _Visitor,
typename... _Variants,
986 struct __gen_vtable_impl<
987 _Multi_array<_Result_type (*)(_Visitor, _Variants...)>,
991 _Multi_array<_Result_type (*)(_Visitor, _Variants...)>;
993 template<
size_t __index,
typename _Variant>
994 static constexpr decltype(
auto)
995 __element_by_index_or_cookie(_Variant&& __var) noexcept
997 if constexpr (__index != variant_npos)
998 return __variant::__get<__index>(std::forward<_Variant>(__var));
1000 return __variant_cookie{};
1003 static constexpr decltype(
auto)
1004 __visit_invoke(_Visitor&& __visitor, _Variants... __vars)
1006 if constexpr (is_same_v<_Result_type, __variant_idx_cookie>)
1010 __element_by_index_or_cookie<__indices>(
1011 std::forward<_Variants>(__vars))...,
1012 integral_constant<size_t, __indices>()...);
1013 else if constexpr (is_same_v<_Result_type, __variant_cookie>)
1016 __element_by_index_or_cookie<__indices>(
1017 std::forward<_Variants>(__vars))...);
1018 else if constexpr (_Array_type::__result_is_deduced::value)
1021 __element_by_index_or_cookie<__indices>(
1022 std::forward<_Variants>(__vars))...);
1024 return std::__invoke_r<_Result_type>(
1025 std::forward<_Visitor>(__visitor),
1026 __variant::__get<__indices>(std::forward<_Variants>(__vars))...);
1029 static constexpr
auto
1031 {
return _Array_type{&__visit_invoke}; }
1034 template<
typename _Result_type,
typename _Visitor,
typename... _Variants>
1038 _Multi_array<_Result_type (*)(_Visitor, _Variants...),
1039 variant_size_v<remove_reference_t<_Variants>>...>;
1041 static constexpr _Array_type _S_vtable
1042 = __gen_vtable_impl<_Array_type, std::index_sequence<>>::_S_apply();
1045 template<
size_t _Np,
typename _Tp>
1046 struct _Base_dedup :
public _Tp { };
1048 template<
typename _Variant,
typename __indices>
1049 struct _Variant_hash_base;
1051 template<
typename... _Types,
size_t... __indices>
1052 struct _Variant_hash_base<variant<_Types...>,
1054 : _Base_dedup<__indices, __poison_hash<remove_const_t<_Types>>>... { };
1056 template<
size_t _Np,
typename _Variant>
1057 using __get_t = decltype(std::get<_Np>(std::declval<_Variant>()));
1060 template<
typename _Visitor,
typename... _Variants>
1061 using __visit_result_t
1062 = invoke_result_t<_Visitor, __get_t<0, _Variants>...>;
1067 template<
size_t _Np,
typename _Variant,
typename... _Args>
1068 void __variant_construct_by_index(_Variant& __v, _Args&&... __args)
1071 auto&& __storage = __detail::__variant::__get<_Np>(__v);
1073 remove_reference_t<decltype(__storage)>
1074 (std::forward<_Args>(__args)...);
1077 template<
typename _Tp,
typename... _Types>
1079 holds_alternative(
const variant<_Types...>& __v) noexcept
1081 static_assert(__detail::__variant::__exactly_once<_Tp, _Types...>,
1082 "T must occur exactly once in alternatives");
1083 return __v.index() == __detail::__variant::__index_of_v<_Tp, _Types...>;
1086 template<
typename _Tp,
typename... _Types>
1087 constexpr _Tp& get(variant<_Types...>& __v)
1089 static_assert(__detail::__variant::__exactly_once<_Tp, _Types...>,
1090 "T must occur exactly once in alternatives");
1091 static_assert(!is_void_v<_Tp>,
"_Tp must not be void");
1092 return std::get<__detail::__variant::__index_of_v<_Tp, _Types...>>(__v);
1095 template<
typename _Tp,
typename... _Types>
1096 constexpr _Tp&& get(variant<_Types...>&& __v)
1098 static_assert(__detail::__variant::__exactly_once<_Tp, _Types...>,
1099 "T must occur exactly once in alternatives");
1100 static_assert(!is_void_v<_Tp>,
"_Tp must not be void");
1101 return std::get<__detail::__variant::__index_of_v<_Tp, _Types...>>(
1105 template<
typename _Tp,
typename... _Types>
1106 constexpr
const _Tp& get(
const variant<_Types...>& __v)
1108 static_assert(__detail::__variant::__exactly_once<_Tp, _Types...>,
1109 "T must occur exactly once in alternatives");
1110 static_assert(!is_void_v<_Tp>,
"_Tp must not be void");
1111 return std::get<__detail::__variant::__index_of_v<_Tp, _Types...>>(__v);
1114 template<
typename _Tp,
typename... _Types>
1115 constexpr
const _Tp&& get(
const variant<_Types...>&& __v)
1117 static_assert(__detail::__variant::__exactly_once<_Tp, _Types...>,
1118 "T must occur exactly once in alternatives");
1119 static_assert(!is_void_v<_Tp>,
"_Tp must not be void");
1120 return std::get<__detail::__variant::__index_of_v<_Tp, _Types...>>(
1124 template<
size_t _Np,
typename... _Types>
1125 constexpr
add_pointer_t<variant_alternative_t<_Np, variant<_Types...>>>
1126 get_if(variant<_Types...>* __ptr) noexcept
1128 using _Alternative_type = variant_alternative_t<_Np, variant<_Types...>>;
1129 static_assert(_Np <
sizeof...(_Types),
1130 "The index must be in [0, number of alternatives)");
1131 static_assert(!is_void_v<_Alternative_type>,
"_Tp must not be void");
1132 if (__ptr && __ptr->index() == _Np)
1137 template<
size_t _Np,
typename... _Types>
1139 add_pointer_t<
const variant_alternative_t<_Np, variant<_Types...>>>
1140 get_if(
const variant<_Types...>* __ptr) noexcept
1142 using _Alternative_type = variant_alternative_t<_Np, variant<_Types...>>;
1143 static_assert(_Np <
sizeof...(_Types),
1144 "The index must be in [0, number of alternatives)");
1145 static_assert(!is_void_v<_Alternative_type>,
"_Tp must not be void");
1146 if (__ptr && __ptr->index() == _Np)
1151 template<
typename _Tp,
typename... _Types>
1152 constexpr add_pointer_t<_Tp>
1153 get_if(variant<_Types...>* __ptr) noexcept
1155 static_assert(__detail::__variant::__exactly_once<_Tp, _Types...>,
1156 "T must occur exactly once in alternatives");
1157 static_assert(!is_void_v<_Tp>,
"_Tp must not be void");
1158 return std::get_if<__detail::__variant::__index_of_v<_Tp, _Types...>>(
1162 template<
typename _Tp,
typename... _Types>
1163 constexpr add_pointer_t<const _Tp>
1164 get_if(
const variant<_Types...>* __ptr) noexcept
1166 static_assert(__detail::__variant::__exactly_once<_Tp, _Types...>,
1167 "T must occur exactly once in alternatives");
1168 static_assert(!is_void_v<_Tp>,
"_Tp must not be void");
1169 return std::get_if<__detail::__variant::__index_of_v<_Tp, _Types...>>(
1173 struct monostate { };
1175 #define _VARIANT_RELATION_FUNCTION_TEMPLATE(__OP, __NAME) \
1176 template<typename... _Types> \
1177 constexpr bool operator __OP(const variant<_Types...>& __lhs, \
1178 const variant<_Types...>& __rhs) \
1180 bool __ret = true; \
1181 __detail::__variant::__raw_idx_visit( \
1182 [&__ret, &__lhs] (auto&& __rhs_mem, auto __rhs_index) mutable \
1184 if constexpr (__rhs_index != variant_npos) \
1186 if (__lhs.index() == __rhs_index) \
1188 auto& __this_mem = std::get<__rhs_index>(__lhs); \
1189 __ret = __this_mem __OP __rhs_mem; \
1192 __ret = (__lhs.index() + 1) __OP (__rhs_index + 1); \
1195 __ret = (__lhs.index() + 1) __OP (__rhs_index + 1); \
1200 _VARIANT_RELATION_FUNCTION_TEMPLATE(<, less)
1201 _VARIANT_RELATION_FUNCTION_TEMPLATE(<=, less_equal)
1202 _VARIANT_RELATION_FUNCTION_TEMPLATE(==, equal)
1203 _VARIANT_RELATION_FUNCTION_TEMPLATE(!=, not_equal)
1204 _VARIANT_RELATION_FUNCTION_TEMPLATE(>=, greater_equal)
1205 _VARIANT_RELATION_FUNCTION_TEMPLATE(>, greater)
1207 #undef _VARIANT_RELATION_FUNCTION_TEMPLATE
1209 constexpr
bool operator==(monostate, monostate) noexcept {
return true; }
1211 #ifdef __cpp_lib_three_way_comparison
1212 template<
typename... _Types>
1213 requires (three_way_comparable<_Types> && ...)
1215 common_comparison_category_t<compare_three_way_result_t<_Types>...>
1216 operator<=>(const variant<_Types...>& __v, const variant<_Types...>& __w)
1218 common_comparison_category_t<compare_three_way_result_t<_Types>...> __ret
1219 = strong_ordering::equal;
1221 __detail::__variant::__raw_idx_visit(
1222 [&__ret, &__v] (
auto&& __w_mem,
auto __w_index)
mutable
1224 if constexpr (__w_index != variant_npos)
1226 if (__v.index() == __w_index)
1228 auto& __this_mem = std::get<__w_index>(__v);
1229 __ret = __this_mem <=> __w_mem;
1233 __ret = (__v.index() + 1) <=> (__w_index + 1);
1238 constexpr strong_ordering
1239 operator<=>(monostate, monostate) noexcept {
return strong_ordering::equal; }
1241 constexpr
bool operator!=(monostate, monostate) noexcept {
return false; }
1242 constexpr
bool operator<(monostate, monostate) noexcept {
return false; }
1243 constexpr
bool operator>(monostate, monostate) noexcept {
return false; }
1244 constexpr
bool operator<=(monostate, monostate) noexcept {
return true; }
1245 constexpr
bool operator>=(monostate, monostate) noexcept {
return true; }
1248 template<
typename _Visitor,
typename... _Variants>
1249 constexpr __detail::__variant::__visit_result_t<_Visitor, _Variants...>
1250 visit(_Visitor&&, _Variants&&...);
1252 template<
typename... _Types>
1253 inline enable_if_t<(is_move_constructible_v<_Types> && ...)
1254 && (is_swappable_v<_Types> && ...)>
1255 swap(variant<_Types...>& __lhs, variant<_Types...>& __rhs)
1256 noexcept(noexcept(__lhs.swap(__rhs)))
1257 { __lhs.swap(__rhs); }
1259 template<
typename... _Types>
1260 enable_if_t<!((is_move_constructible_v<_Types> && ...)
1261 && (is_swappable_v<_Types> && ...))>
1262 swap(variant<_Types...>&, variant<_Types...>&) =
delete;
1264 class bad_variant_access :
public exception
1267 bad_variant_access() noexcept { }
1269 const char* what() const noexcept
override
1270 {
return _M_reason; }
1273 bad_variant_access(
const char* __reason) noexcept : _M_reason(__reason) { }
1276 const char* _M_reason =
"bad variant access";
1278 friend void __throw_bad_variant_access(
const char* __what);
1283 __throw_bad_variant_access(
const char* __what)
1284 { _GLIBCXX_THROW_OR_ABORT(bad_variant_access(__what)); }
1287 __throw_bad_variant_access(
bool __valueless)
1289 if (__valueless) [[__unlikely__]]
1290 __throw_bad_variant_access(
"std::get: variant is valueless");
1292 __throw_bad_variant_access(
"std::get: wrong index for variant");
1295 template<
typename... _Types>
1297 :
private __detail::__variant::_Variant_base<_Types...>,
1298 private _Enable_default_constructor<
1299 __detail::__variant::_Traits<_Types...>::_S_default_ctor,
1300 variant<_Types...>>,
1301 private _Enable_copy_move<
1302 __detail::__variant::_Traits<_Types...>::_S_copy_ctor,
1303 __detail::__variant::_Traits<_Types...>::_S_copy_assign,
1304 __detail::__variant::_Traits<_Types...>::_S_move_ctor,
1305 __detail::__variant::_Traits<_Types...>::_S_move_assign,
1309 template <
typename... _UTypes,
typename _Tp>
1310 friend decltype(
auto) __variant_cast(_Tp&&);
1311 template<
size_t _Np, typename _Variant, typename... _Args>
1312 friend
void __variant_construct_by_index(_Variant& __v,
1315 static_assert(sizeof...(_Types) > 0,
1316 "variant must have at least one alternative");
1317 static_assert(!(
std::is_reference_v<_Types> || ...),
1318 "variant must have no reference alternative");
1319 static_assert(!(
std::is_void_v<_Types> || ...),
1320 "variant must have no
void alternative");
1322 using _Base = __detail::__variant::_Variant_base<_Types...>;
1323 using _Default_ctor_enabler =
1324 _Enable_default_constructor<
1325 __detail::__variant::_Traits<_Types...>::_S_default_ctor,
1326 variant<_Types...>>;
1328 template<typename _Tp>
1329 static constexpr
bool __not_self
1330 = !is_same_v<__remove_cvref_t<_Tp>, variant>;
1332 template<typename _Tp>
1333 static constexpr
bool
1334 __exactly_once = __detail::__variant::__exactly_once<_Tp, _Types...>;
1336 template<typename _Tp>
1337 static constexpr
size_t __accepted_index
1338 = __detail::__variant::__accepted_index<_Tp, variant>::value;
1340 template<
size_t _Np, typename =
enable_if_t<(_Np < sizeof...(_Types))>>
1341 using __to_type = variant_alternative_t<_Np, variant>;
1343 template<typename _Tp, typename =
enable_if_t<__not_self<_Tp>>>
1344 using __accepted_type = __to_type<__accepted_index<_Tp>>;
1346 template<typename _Tp>
1347 static constexpr
size_t __index_of =
1348 __detail::__variant::__index_of_v<_Tp, _Types...>;
1350 using _Traits = __detail::__variant::_Traits<_Types...>;
1352 template<typename _Tp>
1354 template<
typename _Tp>
1355 struct __is_in_place_tag<in_place_type_t<_Tp>> :
true_type { };
1356 template<
size_t _Np>
1357 struct __is_in_place_tag<in_place_index_t<_Np>> :
true_type { };
1359 template<
typename _Tp>
1360 static constexpr
bool __not_in_place_tag
1361 = !__is_in_place_tag<__remove_cvref_t<_Tp>>::value;
1364 variant() =
default;
1365 variant(
const variant& __rhs) =
default;
1366 variant(variant&&) =
default;
1367 variant& operator=(
const variant&) =
default;
1368 variant& operator=(variant&&) =
default;
1369 ~variant() =
default;
1371 template<
typename _Tp,
1374 typename _Tj = __accepted_type<_Tp&&>,
1376 && is_constructible_v<_Tj, _Tp>>>
1379 noexcept(is_nothrow_constructible_v<_Tj, _Tp>)
1380 : variant(in_place_index<__accepted_index<_Tp>>,
1384 template<
typename _Tp,
typename... _Args,
1385 typename = enable_if_t<__exactly_once<_Tp>
1386 && is_constructible_v<_Tp, _Args...>>>
1388 variant(in_place_type_t<_Tp>, _Args&&... __args)
1389 : variant(in_place_index<__index_of<_Tp>>,
1393 template<
typename _Tp,
typename _Up,
typename... _Args,
1394 typename = enable_if_t<__exactly_once<_Tp>
1395 && is_constructible_v<_Tp,
1396 initializer_list<_Up>&, _Args...>>>
1398 variant(in_place_type_t<_Tp>, initializer_list<_Up> __il,
1400 : variant(in_place_index<__index_of<_Tp>>, __il,
1404 template<
size_t _Np,
typename... _Args,
1405 typename _Tp = __to_type<_Np>,
1406 typename =
enable_if_t<is_constructible_v<_Tp, _Args...>>>
1408 variant(in_place_index_t<_Np>, _Args&&... __args)
1409 : _Base(in_place_index<_Np>,
std::
forward<_Args>(__args)...),
1410 _Default_ctor_enabler(_Enable_default_constructor_tag{})
1413 template<
size_t _Np,
typename _Up,
typename... _Args,
1414 typename _Tp = __to_type<_Np>,
1416 initializer_list<_Up>&,
1419 variant(in_place_index_t<_Np>, initializer_list<_Up> __il,
1421 : _Base(in_place_index<_Np>, __il,
std::
forward<_Args>(__args)...),
1422 _Default_ctor_enabler(_Enable_default_constructor_tag{})
1425 template<
typename _Tp>
1426 enable_if_t<__exactly_once<__accepted_type<_Tp&&>>
1427 && is_constructible_v<__accepted_type<_Tp&&>, _Tp>
1428 && is_assignable_v<__accepted_type<_Tp&&>&, _Tp>,
1430 operator=(_Tp&& __rhs)
1431 noexcept(is_nothrow_assignable_v<__accepted_type<_Tp&&>&, _Tp>
1432 && is_nothrow_constructible_v<__accepted_type<_Tp&&>, _Tp>)
1434 constexpr
auto __index = __accepted_index<_Tp>;
1435 if (index() == __index)
1436 std::get<__index>(*
this) = std::forward<_Tp>(__rhs);
1439 using _Tj = __accepted_type<_Tp&&>;
1440 if constexpr (is_nothrow_constructible_v<_Tj, _Tp>
1441 || !is_nothrow_move_constructible_v<_Tj>)
1442 this->emplace<__index>(std::forward<_Tp>(__rhs));
1444 operator=(variant(std::forward<_Tp>(__rhs)));
1449 template<
typename _Tp,
typename... _Args>
1450 enable_if_t<is_constructible_v<_Tp, _Args...> && __exactly_once<_Tp>,
1452 emplace(_Args&&... __args)
1454 constexpr
size_t __index = __index_of<_Tp>;
1455 return this->emplace<__index>(std::forward<_Args>(__args)...);
1458 template<
typename _Tp,
typename _Up,
typename... _Args>
1459 enable_if_t<is_constructible_v<_Tp, initializer_list<_Up>&, _Args...>
1460 && __exactly_once<_Tp>,
1462 emplace(initializer_list<_Up> __il, _Args&&... __args)
1464 constexpr
size_t __index = __index_of<_Tp>;
1465 return this->emplace<__index>(__il, std::forward<_Args>(__args)...);
1468 template<
size_t _Np,
typename... _Args>
1469 enable_if_t<is_constructible_v<variant_alternative_t<_Np, variant>,
1471 variant_alternative_t<_Np, variant>&>
1472 emplace(_Args&&... __args)
1474 static_assert(_Np <
sizeof...(_Types),
1475 "The index must be in [0, number of alternatives)");
1476 using type = variant_alternative_t<_Np, variant>;
1479 if constexpr (is_nothrow_constructible_v<type, _Args...>)
1482 __variant_construct_by_index<_Np>(*
this,
1483 std::forward<_Args>(__args)...);
1485 else if constexpr (is_scalar_v<type>)
1488 const type __tmp(std::forward<_Args>(__args)...);
1491 __variant_construct_by_index<_Np>(*
this, __tmp);
1493 else if constexpr (__detail::__variant::_Never_valueless_alt<type>()
1494 && _Traits::_S_move_assign)
1497 variant __tmp(in_place_index<_Np>,
1498 std::forward<_Args>(__args)...);
1509 __variant_construct_by_index<_Np>(*
this,
1510 std::forward<_Args>(__args)...);
1514 this->_M_index = variant_npos;
1515 __throw_exception_again;
1518 return std::get<_Np>(*
this);
1521 template<
size_t _Np,
typename _Up,
typename... _Args>
1522 enable_if_t<is_constructible_v<variant_alternative_t<_Np, variant>,
1523 initializer_list<_Up>&, _Args...>,
1524 variant_alternative_t<_Np, variant>&>
1525 emplace(initializer_list<_Up> __il, _Args&&... __args)
1527 static_assert(_Np <
sizeof...(_Types),
1528 "The index must be in [0, number of alternatives)");
1529 using type = variant_alternative_t<_Np, variant>;
1532 if constexpr (is_nothrow_constructible_v<type,
1533 initializer_list<_Up>&,
1537 __variant_construct_by_index<_Np>(*
this, __il,
1538 std::forward<_Args>(__args)...);
1540 else if constexpr (__detail::__variant::_Never_valueless_alt<type>()
1541 && _Traits::_S_move_assign)
1544 variant __tmp(in_place_index<_Np>, __il,
1545 std::forward<_Args>(__args)...);
1556 __variant_construct_by_index<_Np>(*
this, __il,
1557 std::forward<_Args>(__args)...);
1561 this->_M_index = variant_npos;
1562 __throw_exception_again;
1565 return std::get<_Np>(*
this);
1568 constexpr
bool valueless_by_exception() const noexcept
1569 {
return !this->_M_valid(); }
1571 constexpr
size_t index() const noexcept
1573 using __index_type =
typename _Base::__index_type;
1574 if constexpr (__detail::__variant::__never_valueless<_Types...>())
1575 return this->_M_index;
1576 else if constexpr (sizeof...(_Types) <= __index_type(-1) / 2)
1579 return
size_t(__index_type(this->_M_index + 1)) - 1;
1583 swap(variant& __rhs)
1584 noexcept((__is_nothrow_swappable<_Types>::value && ...)
1585 && is_nothrow_move_constructible_v<variant>)
1587 __detail::__variant::__raw_idx_visit(
1588 [
this, &__rhs](
auto&& __rhs_mem,
auto __rhs_index)
mutable
1590 if constexpr (__rhs_index != variant_npos)
1592 if (this->index() == __rhs_index)
1595 std::get<__rhs_index>(*
this);
1597 swap(__this_mem, __rhs_mem);
1601 if (!this->valueless_by_exception()) [[__likely__]]
1605 this->_M_destructive_move(__rhs_index,
1610 this->_M_destructive_move(__rhs_index,
1618 if (!this->valueless_by_exception()) [[__likely__]]
1629 #if defined(__clang__) && __clang_major__ <= 7
1635 template<
size_t _Np,
typename _Vp>
1636 friend constexpr decltype(
auto)
1637 __detail::__variant::__get(_Vp&& __v) noexcept;
1639 template<typename _Vp>
1641 __detail::__variant::__get_storage(_Vp&& __v) noexcept;
1643 #define _VARIANT_RELATION_FUNCTION_TEMPLATE(__OP) \
1644 template<typename... _Tp> \
1645 friend constexpr bool \
1646 operator __OP(const variant<_Tp...>& __lhs, \
1647 const variant<_Tp...>& __rhs);
1649 _VARIANT_RELATION_FUNCTION_TEMPLATE(<)
1650 _VARIANT_RELATION_FUNCTION_TEMPLATE(<=)
1651 _VARIANT_RELATION_FUNCTION_TEMPLATE(==)
1652 _VARIANT_RELATION_FUNCTION_TEMPLATE(!=)
1653 _VARIANT_RELATION_FUNCTION_TEMPLATE(>=)
1654 _VARIANT_RELATION_FUNCTION_TEMPLATE(>)
1656 #undef _VARIANT_RELATION_FUNCTION_TEMPLATE
1659 template<
size_t _Np,
typename... _Types>
1660 constexpr variant_alternative_t<_Np, variant<_Types...>>&
1661 get(variant<_Types...>& __v)
1663 static_assert(_Np <
sizeof...(_Types),
1664 "The index must be in [0, number of alternatives)");
1665 if (__v.index() != _Np)
1666 __throw_bad_variant_access(__v.valueless_by_exception());
1667 return __detail::__variant::__get<_Np>(__v);
1670 template<
size_t _Np,
typename... _Types>
1671 constexpr variant_alternative_t<_Np, variant<_Types...>>&&
1672 get(variant<_Types...>&& __v)
1674 static_assert(_Np <
sizeof...(_Types),
1675 "The index must be in [0, number of alternatives)");
1676 if (__v.index() != _Np)
1677 __throw_bad_variant_access(__v.valueless_by_exception());
1678 return __detail::__variant::__get<_Np>(
std::move(__v));
1681 template<
size_t _Np,
typename... _Types>
1682 constexpr
const variant_alternative_t<_Np, variant<_Types...>>&
1683 get(
const variant<_Types...>& __v)
1685 static_assert(_Np <
sizeof...(_Types),
1686 "The index must be in [0, number of alternatives)");
1687 if (__v.index() != _Np)
1688 __throw_bad_variant_access(__v.valueless_by_exception());
1689 return __detail::__variant::__get<_Np>(__v);
1692 template<
size_t _Np,
typename... _Types>
1693 constexpr
const variant_alternative_t<_Np, variant<_Types...>>&&
1694 get(
const variant<_Types...>&& __v)
1696 static_assert(_Np <
sizeof...(_Types),
1697 "The index must be in [0, number of alternatives)");
1698 if (__v.index() != _Np)
1699 __throw_bad_variant_access(__v.valueless_by_exception());
1700 return __detail::__variant::__get<_Np>(
std::move(__v));
1703 template<
typename _Result_type,
typename _Visitor,
typename... _Variants>
1704 constexpr decltype(
auto)
1705 __do_visit(_Visitor&& __visitor, _Variants&&... __variants)
1707 constexpr
auto& __vtable = __detail::__variant::__gen_vtable<
1708 _Result_type, _Visitor&&, _Variants&&...>::_S_vtable;
1710 auto __func_ptr = __vtable._M_access(__variants.index()...);
1711 return (*__func_ptr)(std::forward<_Visitor>(__visitor),
1712 std::forward<_Variants>(__variants)...);
1715 template<
typename _Visitor,
typename... _Variants>
1716 constexpr __detail::__variant::__visit_result_t<_Visitor, _Variants...>
1717 visit(_Visitor&& __visitor, _Variants&&... __variants)
1719 if ((__variants.valueless_by_exception() || ...))
1720 __throw_bad_variant_access(
"std::visit: variant is valueless");
1723 = __detail::__variant::__visit_result_t<_Visitor, _Variants...>;
1725 using _Tag = __detail::__variant::__deduce_visit_result<_Result_type>;
1727 return std::__do_visit<_Tag>(std::forward<_Visitor>(__visitor),
1728 std::forward<_Variants>(__variants)...);
1731 #if __cplusplus > 201703L
1732 template<
typename _Res,
typename _Visitor,
typename... _Variants>
1734 visit(_Visitor&& __visitor, _Variants&&... __variants)
1736 if ((__variants.valueless_by_exception() || ...))
1737 __throw_bad_variant_access(
"std::visit<R>: variant is valueless");
1739 return std::__do_visit<_Res>(std::forward<_Visitor>(__visitor),
1740 std::forward<_Variants>(__variants)...);
1744 template<bool,
typename... _Types>
1745 struct __variant_hash_call_base_impl
1748 operator()(
const variant<_Types...>& __t)
const
1749 noexcept((is_nothrow_invocable_v<hash<decay_t<_Types>>, _Types> && ...))
1752 __detail::__variant::__raw_visit(
1753 [&__t, &__ret](
auto&& __t_mem)
mutable
1755 using _Type = __remove_cvref_t<decltype(__t_mem)>;
1756 if constexpr (!is_same_v<_Type,
1757 __detail::__variant::__variant_cookie>)
1758 __ret =
std::hash<
size_t>{}(__t.index())
1767 template<
typename... _Types>
1768 struct __variant_hash_call_base_impl<false, _Types...> {};
1770 template<
typename... _Types>
1771 using __variant_hash_call_base =
1772 __variant_hash_call_base_impl<(__poison_hash<remove_const_t<_Types>>::
1773 __enable_hash_call &&...), _Types...>;
1775 template<
typename... _Types>
1776 struct hash<variant<_Types...>>
1777 :
private __detail::__variant::_Variant_hash_base<
1778 variant<_Types...>, std::index_sequence_for<_Types...>>,
1779 public __variant_hash_call_base<_Types...>
1781 using result_type [[__deprecated__]] = size_t;
1782 using argument_type [[__deprecated__]] = variant<_Types...>;
1786 struct hash<monostate>
1788 using result_type [[__deprecated__]] = size_t;
1789 using argument_type [[__deprecated__]] = monostate;
1792 operator()(
const monostate&)
const noexcept
1794 constexpr
size_t __magic_monostate_hash = -7777;
1795 return __magic_monostate_hash;
1799 template<
typename... _Types>
1800 struct __is_fast_hash<hash<variant<_Types...>>>
1801 : bool_constant<(__is_fast_hash<_Types>::value && ...)>
1804 _GLIBCXX_END_NAMESPACE_VERSION
typename remove_reference< _Tp >::type remove_reference_t
Alias template for remove_reference.
void void_t
A metafunction that always yields void, used for detecting valid types.
integral_constant< bool, true > true_type
The type used as a compile-time boolean with true value.
typename add_pointer< _Tp >::type add_pointer_t
Alias template for add_pointer.
typename make_signed< _Tp >::type make_signed_t
Alias template for make_signed.
typename enable_if< _Cond, _Tp >::type enable_if_t
Alias template for enable_if.
integral_constant< bool, false > false_type
The type used as a compile-time boolean with false value.
constexpr __invoke_result< _Callable, _Args... >::type __invoke(_Callable &&__fn, _Args &&... __args) noexcept(__is_nothrow_invocable< _Callable, _Args... >::value)
Invoke a callable object.
constexpr std::remove_reference< _Tp >::type && move(_Tp &&__t) noexcept
Convert a value to an rvalue.
constexpr _Tp && forward(typename std::remove_reference< _Tp >::type &__t) noexcept
Forward an lvalue.
constexpr _Tp * addressof(_Tp &__r) noexcept
Returns the actual address of the object or function referenced by r, even in the presence of an over...
ISO C++ entities toplevel namespace is std.
make_integer_sequence< size_t, _Num > make_index_sequence
Alias template make_index_sequence.
integer_sequence< size_t, _Idx... > index_sequence
Alias template index_sequence.
Primary class template hash.
Class template integer_sequence.