29#ifndef _GLIBCXX_VARIANT
30#define _GLIBCXX_VARIANT 1
32#pragma GCC system_header
34#if __cplusplus >= 201703L
46#if __cplusplus >= 202002L
50#if __cpp_concepts >= 202002L && __cpp_constexpr >= 201811L
52# define __cpp_lib_variant 202106L
55# define __cpp_lib_variant 202102L
58namespace std _GLIBCXX_VISIBILITY(default)
60_GLIBCXX_BEGIN_NAMESPACE_VERSION
62 template<
typename... _Types>
class tuple;
63 template<
typename... _Types>
class variant;
64 template <
typename>
struct hash;
66 template<
typename _Variant>
69 template<
typename _Variant>
70 struct variant_size<const _Variant> : variant_size<_Variant> {};
72 template<
typename _Variant>
73 struct variant_size<volatile _Variant> : variant_size<_Variant> {};
75 template<
typename _Variant>
76 struct variant_size<const volatile _Variant> : variant_size<_Variant> {};
78 template<
typename... _Types>
79 struct variant_size<variant<_Types...>>
82 template<
typename _Variant>
83 inline constexpr size_t variant_size_v = variant_size<_Variant>::value;
85 template<
typename... _Types>
86 inline constexpr size_t
87 variant_size_v<variant<_Types...>> =
sizeof...(_Types);
89 template<
typename... _Types>
90 inline constexpr size_t
91 variant_size_v<
const variant<_Types...>> =
sizeof...(_Types);
93 template<
size_t _Np,
typename _Variant>
94 struct variant_alternative;
96 template<
size_t _Np,
typename... _Types>
97 struct variant_alternative<_Np, variant<_Types...>>
99 static_assert(_Np <
sizeof...(_Types));
101 using type =
typename _Nth_type<_Np, _Types...>::type;
104 template<
size_t _Np,
typename _Variant>
105 using variant_alternative_t =
106 typename variant_alternative<_Np, _Variant>::type;
108 template<
size_t _Np,
typename _Variant>
109 struct variant_alternative<_Np, const _Variant>
110 {
using type =
const variant_alternative_t<_Np, _Variant>; };
112 template<
size_t _Np,
typename _Variant>
113 struct variant_alternative<_Np, volatile _Variant>
114 {
using type =
volatile variant_alternative_t<_Np, _Variant>; };
116 template<
size_t _Np,
typename _Variant>
117 struct variant_alternative<_Np, const volatile _Variant>
118 {
using type =
const volatile variant_alternative_t<_Np, _Variant>; };
120 inline constexpr size_t variant_npos = -1;
122 template<
size_t _Np,
typename... _Types>
123 constexpr variant_alternative_t<_Np, variant<_Types...>>&
124 get(variant<_Types...>&);
126 template<
size_t _Np,
typename... _Types>
127 constexpr variant_alternative_t<_Np, variant<_Types...>>&&
128 get(variant<_Types...>&&);
130 template<
size_t _Np,
typename... _Types>
131 constexpr variant_alternative_t<_Np, variant<_Types...>>
const&
132 get(
const variant<_Types...>&);
134 template<
size_t _Np,
typename... _Types>
135 constexpr variant_alternative_t<_Np, variant<_Types...>>
const&&
136 get(
const variant<_Types...>&&);
138 template<
typename _Result_type,
typename _Visitor,
typename... _Variants>
139 constexpr decltype(
auto)
140 __do_visit(_Visitor&& __visitor, _Variants&&... __variants);
142 template <
typename... _Types,
typename _Tp>
145 __variant_cast(_Tp&& __rhs)
147 if constexpr (is_lvalue_reference_v<_Tp>)
149 if constexpr (is_const_v<remove_reference_t<_Tp>>)
150 return static_cast<const variant<_Types...
>&>(__rhs);
152 return static_cast<variant<_Types...
>&>(__rhs);
155 return static_cast<variant<_Types...
>&&>(__rhs);
163 struct __variant_cookie {};
165 struct __variant_idx_cookie {
using type = __variant_idx_cookie; };
167 template<
typename _Tp>
struct __deduce_visit_result {
using type = _Tp; };
170 template<
typename _Visitor,
typename... _Variants>
172 __raw_visit(_Visitor&& __visitor, _Variants&&... __variants)
174 std::__do_visit<__variant_cookie>(std::forward<_Visitor>(__visitor),
175 std::forward<_Variants>(__variants)...);
179 template<
typename _Visitor,
typename... _Variants>
181 __raw_idx_visit(_Visitor&& __visitor, _Variants&&... __variants)
183 std::__do_visit<__variant_idx_cookie>(std::forward<_Visitor>(__visitor),
184 std::forward<_Variants>(__variants)...);
189 template<
typename... _Types>
190 constexpr std::variant<_Types...>&
191 __as(std::variant<_Types...>& __v)
noexcept
194 template<
typename... _Types>
195 constexpr const std::variant<_Types...>&
196 __as(
const std::variant<_Types...>& __v)
noexcept
199 template<
typename... _Types>
200 constexpr std::variant<_Types...>&&
201 __as(std::variant<_Types...>&& __v)
noexcept
204 template<
typename... _Types>
205 constexpr const std::variant<_Types...>&&
206 __as(
const std::variant<_Types...>&& __v)
noexcept
215 template<
typename _Type,
bool = std::is_trivially_destructible_v<_Type>>
216 struct _Uninitialized;
218 template<
typename _Type>
219 struct _Uninitialized<_Type, true>
221 template<
typename... _Args>
223 _Uninitialized(in_place_index_t<0>, _Args&&... __args)
227 constexpr const _Type& _M_get() const & noexcept
228 {
return _M_storage; }
230 constexpr _Type& _M_get() &
noexcept
231 {
return _M_storage; }
233 constexpr const _Type&& _M_get() const && noexcept
236 constexpr _Type&& _M_get() &&
noexcept
242 template<
typename _Type>
243 struct _Uninitialized<_Type, false>
245#if __cpp_lib_variant >= 202106L
246 template<
typename... _Args>
248 _Uninitialized(in_place_index_t<0>, _Args&&... __args)
252 constexpr ~_Uninitialized() { }
254 _Uninitialized(
const _Uninitialized&) =
default;
255 _Uninitialized(_Uninitialized&&) =
default;
256 _Uninitialized& operator=(
const _Uninitialized&) =
default;
257 _Uninitialized& operator=(_Uninitialized&&) =
default;
259 constexpr const _Type& _M_get() const & noexcept
260 {
return _M_storage; }
262 constexpr _Type& _M_get() &
noexcept
263 {
return _M_storage; }
265 constexpr const _Type&& _M_get() const && noexcept
268 constexpr _Type&& _M_get() &&
noexcept
271 struct _Empty_byte { };
274 _Empty_byte _M_empty;
278 template<
typename... _Args>
280 _Uninitialized(in_place_index_t<0>, _Args&&... __args)
283 _Type(std::forward<_Args>(__args)...);
286 const _Type& _M_get() const & noexcept
287 {
return *_M_storage._M_ptr(); }
289 _Type& _M_get() &
noexcept
290 {
return *_M_storage._M_ptr(); }
292 const _Type&& _M_get() const && noexcept
293 {
return std::move(*_M_storage._M_ptr()); }
295 _Type&& _M_get() &&
noexcept
296 {
return std::move(*_M_storage._M_ptr()); }
298 __gnu_cxx::__aligned_membuf<_Type> _M_storage;
302 template<
size_t _Np,
typename _Union>
303 constexpr decltype(
auto)
304 __get_n(_Union&& __u)
noexcept
306 if constexpr (_Np == 0)
307 return std::forward<_Union>(__u)._M_first._M_get();
308 else if constexpr (_Np == 1)
309 return std::forward<_Union>(__u)._M_rest._M_first._M_get();
310 else if constexpr (_Np == 2)
311 return std::forward<_Union>(__u)._M_rest._M_rest._M_first._M_get();
313 return __variant::__get_n<_Np - 3>(
314 std::forward<_Union>(__u)._M_rest._M_rest._M_rest);
318 template<
size_t _Np,
typename _Variant>
319 constexpr decltype(
auto)
320 __get(_Variant&& __v)
noexcept
321 {
return __variant::__get_n<_Np>(std::forward<_Variant>(__v)._M_u); }
323 template<
typename... _Types>
326 static constexpr bool _S_default_ctor =
327 is_default_constructible_v<
typename _Nth_type<0, _Types...>::type>;
328 static constexpr bool _S_copy_ctor =
329 (is_copy_constructible_v<_Types> && ...);
330 static constexpr bool _S_move_ctor =
331 (is_move_constructible_v<_Types> && ...);
332 static constexpr bool _S_copy_assign =
334 && (is_copy_assignable_v<_Types> && ...);
335 static constexpr bool _S_move_assign =
337 && (is_move_assignable_v<_Types> && ...);
339 static constexpr bool _S_trivial_dtor =
340 (is_trivially_destructible_v<_Types> && ...);
341 static constexpr bool _S_trivial_copy_ctor =
342 (is_trivially_copy_constructible_v<_Types> && ...);
343 static constexpr bool _S_trivial_move_ctor =
344 (is_trivially_move_constructible_v<_Types> && ...);
345 static constexpr bool _S_trivial_copy_assign =
346 _S_trivial_dtor && _S_trivial_copy_ctor
347 && (is_trivially_copy_assignable_v<_Types> && ...);
348 static constexpr bool _S_trivial_move_assign =
349 _S_trivial_dtor && _S_trivial_move_ctor
350 && (is_trivially_move_assignable_v<_Types> && ...);
354 static constexpr bool _S_nothrow_default_ctor =
355 is_nothrow_default_constructible_v<
356 typename _Nth_type<0, _Types...>::type>;
357 static constexpr bool _S_nothrow_copy_ctor =
false;
358 static constexpr bool _S_nothrow_move_ctor =
359 (is_nothrow_move_constructible_v<_Types> && ...);
360 static constexpr bool _S_nothrow_copy_assign =
false;
361 static constexpr bool _S_nothrow_move_assign =
363 && (is_nothrow_move_assignable_v<_Types> && ...);
367 template<
typename... _Types>
368 union _Variadic_union
370 _Variadic_union() =
default;
372 template<
size_t _Np,
typename... _Args>
373 _Variadic_union(in_place_index_t<_Np>, _Args&&...) =
delete;
376 template<
typename _First,
typename... _Rest>
377 union _Variadic_union<_First, _Rest...>
379 constexpr _Variadic_union() : _M_rest() { }
381 template<
typename... _Args>
383 _Variadic_union(in_place_index_t<0>, _Args&&... __args)
384 : _M_first(in_place_index<0>,
std::
forward<_Args>(__args)...)
387 template<
size_t _Np,
typename... _Args>
389 _Variadic_union(in_place_index_t<_Np>, _Args&&... __args)
390 : _M_rest(in_place_index<_Np-1>,
std::
forward<_Args>(__args)...)
393#if __cpp_lib_variant >= 202106L
394 _Variadic_union(
const _Variadic_union&) =
default;
395 _Variadic_union(_Variadic_union&&) =
default;
396 _Variadic_union& operator=(
const _Variadic_union&) =
default;
397 _Variadic_union& operator=(_Variadic_union&&) =
default;
399 ~_Variadic_union() =
default;
401 constexpr ~_Variadic_union()
402 requires (!__has_trivial_destructor(_First))
403 || (!__has_trivial_destructor(_Variadic_union<_Rest...>))
407 _Uninitialized<_First> _M_first;
408 _Variadic_union<_Rest...> _M_rest;
416 template<
typename _Tp>
417 struct _Never_valueless_alt
418 : __and_<bool_constant<sizeof(_Tp) <= 256>, is_trivially_copyable<_Tp>>
431 template <typename... _Types>
432 constexpr bool __never_valueless()
434 return _Traits<_Types...>::_S_move_assign
435 && (_Never_valueless_alt<_Types>::value && ...);
439 template<bool __trivially_destructible, typename... _Types>
440 struct _Variant_storage;
442 template <typename... _Types>
443 using __select_index =
444 typename __select_int::_Select_int_base<sizeof...(_Types),
446 unsigned short>::type::value_type;
448 template<typename... _Types>
449 struct _Variant_storage<false, _Types...>
453 : _M_index(static_cast<__index_type>(variant_npos))
456 template<size_t _Np, typename... _Args>
458 _Variant_storage(in_place_index_t<_Np>, _Args&&... __args)
459 : _M_u(in_place_index<_Np>, std::forward<_Args>(__args)...),
466 if (!_M_valid()) [[unlikely]]
469 std::__do_visit<void>([](auto&& __this_mem) mutable
471 std::_Destroy(std::__addressof(__this_mem));
472 }, __variant_cast<_Types...>(*this));
474 _M_index = static_cast<__index_type>(variant_npos);
482 _M_valid() const noexcept
484 if constexpr (__variant::__never_valueless<_Types...>())
486 return this->_M_index != __index_type(variant_npos);
489 _Variadic_union<_Types...> _M_u;
490 using __index_type = __select_index<_Types...>;
491 __index_type _M_index;
494 template<typename... _Types>
495 struct _Variant_storage<true, _Types...>
499 : _M_index(static_cast<__index_type>(variant_npos))
502 template<
size_t _Np,
typename... _Args>
504 _Variant_storage(in_place_index_t<_Np>, _Args&&... __args)
505 : _M_u(in_place_index<_Np>,
std::
forward<_Args>(__args)...),
511 { _M_index =
static_cast<__index_type
>(variant_npos); }
514 _M_valid() const noexcept
516 if constexpr (__variant::__never_valueless<_Types...>())
524 return this->_M_index !=
static_cast<__index_type
>(variant_npos);
527 _Variadic_union<_Types...> _M_u;
528 using __index_type = __select_index<_Types...>;
529 __index_type _M_index;
533 template<
size_t _Np,
bool _Triv,
typename... _Types,
typename... _Args>
536 __emplace(_Variant_storage<_Triv, _Types...>& __v, _Args&&... __args)
545 template<
typename... _Types>
546 using _Variant_storage_alias =
547 _Variant_storage<_Traits<_Types...>::_S_trivial_dtor, _Types...>;
552 template<bool,
typename... _Types>
553 struct _Copy_ctor_base : _Variant_storage_alias<_Types...>
555 using _Base = _Variant_storage_alias<_Types...>;
559 _Copy_ctor_base(
const _Copy_ctor_base& __rhs)
560 noexcept(_Traits<_Types...>::_S_nothrow_copy_ctor)
562 __variant::__raw_idx_visit(
563 [
this](
auto&& __rhs_mem,
auto __rhs_index)
mutable
565 constexpr size_t __j = __rhs_index;
566 if constexpr (__j != variant_npos)
568 in_place_index<__j>, __rhs_mem);
569 }, __variant_cast<_Types...>(__rhs));
570 this->_M_index = __rhs._M_index;
573 _Copy_ctor_base(_Copy_ctor_base&&) =
default;
574 _Copy_ctor_base& operator=(
const _Copy_ctor_base&) =
default;
575 _Copy_ctor_base& operator=(_Copy_ctor_base&&) =
default;
578 template<
typename... _Types>
579 struct _Copy_ctor_base<true, _Types...> : _Variant_storage_alias<_Types...>
581 using _Base = _Variant_storage_alias<_Types...>;
585 template<
typename... _Types>
586 using _Copy_ctor_alias =
587 _Copy_ctor_base<_Traits<_Types...>::_S_trivial_copy_ctor, _Types...>;
589 template<bool,
typename... _Types>
590 struct _Move_ctor_base : _Copy_ctor_alias<_Types...>
592 using _Base = _Copy_ctor_alias<_Types...>;
596 _Move_ctor_base(_Move_ctor_base&& __rhs)
597 noexcept(_Traits<_Types...>::_S_nothrow_move_ctor)
599 __variant::__raw_idx_visit(
600 [
this](
auto&& __rhs_mem,
auto __rhs_index)
mutable
602 constexpr size_t __j = __rhs_index;
603 if constexpr (__j != variant_npos)
607 }, __variant_cast<_Types...>(
std::move(__rhs)));
608 this->_M_index = __rhs._M_index;
611 _Move_ctor_base(
const _Move_ctor_base&) =
default;
612 _Move_ctor_base& operator=(
const _Move_ctor_base&) =
default;
613 _Move_ctor_base& operator=(_Move_ctor_base&&) =
default;
616 template<
typename... _Types>
617 struct _Move_ctor_base<true, _Types...> : _Copy_ctor_alias<_Types...>
619 using _Base = _Copy_ctor_alias<_Types...>;
623 template<
typename... _Types>
624 using _Move_ctor_alias =
625 _Move_ctor_base<_Traits<_Types...>::_S_trivial_move_ctor, _Types...>;
627 template<bool,
typename... _Types>
628 struct _Copy_assign_base : _Move_ctor_alias<_Types...>
630 using _Base = _Move_ctor_alias<_Types...>;
635 operator=(
const _Copy_assign_base& __rhs)
636 noexcept(_Traits<_Types...>::_S_nothrow_copy_assign)
638 __variant::__raw_idx_visit(
639 [
this](
auto&& __rhs_mem,
auto __rhs_index)
mutable
641 constexpr size_t __j = __rhs_index;
642 if constexpr (__j == variant_npos)
644 else if (this->_M_index == __j)
645 __variant::__get<__j>(*
this) = __rhs_mem;
648 using _Tj =
typename _Nth_type<__j, _Types...>::type;
649 if constexpr (is_nothrow_copy_constructible_v<_Tj>
650 || !is_nothrow_move_constructible_v<_Tj>)
651 __variant::__emplace<__j>(*
this, __rhs_mem);
654 using _Variant = variant<_Types...>;
655 _Variant& __self = __variant_cast<_Types...>(*this);
656 __self = _Variant(in_place_index<__j>, __rhs_mem);
659 }, __variant_cast<_Types...>(__rhs));
663 _Copy_assign_base(
const _Copy_assign_base&) =
default;
664 _Copy_assign_base(_Copy_assign_base&&) =
default;
665 _Copy_assign_base& operator=(_Copy_assign_base&&) =
default;
668 template<
typename... _Types>
669 struct _Copy_assign_base<true, _Types...> : _Move_ctor_alias<_Types...>
671 using _Base = _Move_ctor_alias<_Types...>;
675 template<
typename... _Types>
676 using _Copy_assign_alias =
677 _Copy_assign_base<_Traits<_Types...>::_S_trivial_copy_assign, _Types...>;
679 template<bool,
typename... _Types>
680 struct _Move_assign_base : _Copy_assign_alias<_Types...>
682 using _Base = _Copy_assign_alias<_Types...>;
687 operator=(_Move_assign_base&& __rhs)
688 noexcept(_Traits<_Types...>::_S_nothrow_move_assign)
690 __variant::__raw_idx_visit(
691 [
this](
auto&& __rhs_mem,
auto __rhs_index)
mutable
693 constexpr size_t __j = __rhs_index;
694 if constexpr (__j != variant_npos)
696 if (this->_M_index == __j)
697 __variant::__get<__j>(*
this) =
std::move(__rhs_mem);
700 using _Tj =
typename _Nth_type<__j, _Types...>::type;
701 if constexpr (is_nothrow_move_constructible_v<_Tj>)
702 __variant::__emplace<__j>(*
this,
std::move(__rhs_mem));
705 using _Variant = variant<_Types...>;
706 _Variant& __self = __variant_cast<_Types...>(*this);
707 __self.template emplace<__j>(
std::move(__rhs_mem));
713 }, __variant_cast<_Types...>(__rhs));
717 _Move_assign_base(
const _Move_assign_base&) =
default;
718 _Move_assign_base(_Move_assign_base&&) =
default;
719 _Move_assign_base& operator=(
const _Move_assign_base&) =
default;
722 template<
typename... _Types>
723 struct _Move_assign_base<true, _Types...> : _Copy_assign_alias<_Types...>
725 using _Base = _Copy_assign_alias<_Types...>;
729 template<
typename... _Types>
730 using _Move_assign_alias =
731 _Move_assign_base<_Traits<_Types...>::_S_trivial_move_assign, _Types...>;
733 template<
typename... _Types>
734 struct _Variant_base : _Move_assign_alias<_Types...>
736 using _Base = _Move_assign_alias<_Types...>;
739 _Variant_base() noexcept(_Traits<_Types...>::_S_nothrow_default_ctor)
740 : _Variant_base(in_place_index<0>) { }
742 template<
size_t _Np,
typename... _Args>
744 _Variant_base(in_place_index_t<_Np> __i, _Args&&... __args)
748 _Variant_base(
const _Variant_base&) =
default;
749 _Variant_base(_Variant_base&&) =
default;
750 _Variant_base& operator=(
const _Variant_base&) =
default;
751 _Variant_base& operator=(_Variant_base&&) =
default;
754 template<
typename _Tp,
typename... _Types>
755 inline constexpr bool __exactly_once
756 = std::__find_uniq_type_in_pack<_Tp, _Types...>() <
sizeof...(_Types);
759 template<
typename _Ti>
struct _Arr { _Ti _M_x[1]; };
762 template<
size_t _Ind,
typename _Tp,
typename _Ti,
typename =
void>
767 void _S_fun() =
delete;
771 template<
size_t _Ind,
typename _Tp,
typename _Ti>
772 struct _Build_FUN<_Ind, _Tp, _Ti,
773 void_t<decltype(_Arr<_Ti>{{std::declval<_Tp>()}})>>
776 static integral_constant<size_t, _Ind> _S_fun(_Ti);
779 template<
typename _Tp,
typename _Variant,
780 typename = make_index_sequence<variant_size_v<_Variant>>>
783 template<
typename _Tp,
typename... _Ti,
size_t... _Ind>
785 : _Build_FUN<_Ind, _Tp, _Ti>...
787 using _Build_FUN<_Ind, _Tp, _Ti>::_S_fun...;
792 template<
typename _Tp,
typename _Variant>
794 =
decltype(_Build_FUNs<_Tp, _Variant>::_S_fun(std::declval<_Tp>()));
797 template<
typename _Tp,
typename _Variant,
typename =
void>
798 inline constexpr size_t
799 __accepted_index = variant_npos;
801 template<
typename _Tp,
typename _Variant>
802 inline constexpr size_t
803 __accepted_index<_Tp, _Variant, void_t<_FUN_type<_Tp, _Variant>>>
804 = _FUN_type<_Tp, _Variant>::value;
806 template<
typename _Maybe_variant_cookie,
typename _Variant,
807 typename = __remove_cvref_t<_Variant>>
808 inline constexpr bool
809 __extra_visit_slot_needed =
false;
811 template<
typename _Var,
typename... _Types>
812 inline constexpr bool
813 __extra_visit_slot_needed<__variant_cookie, _Var, variant<_Types...>>
814 = !__variant::__never_valueless<_Types...>();
816 template<
typename _Var,
typename... _Types>
817 inline constexpr bool
818 __extra_visit_slot_needed<__variant_idx_cookie, _Var, variant<_Types...>>
819 = !__variant::__never_valueless<_Types...>();
822 template<
typename _Tp,
size_t... _Dimensions>
826 template<
typename _Tp>
827 struct _Multi_array<_Tp>
830 struct __untag_result
832 {
using element_type = _Tp; };
834#pragma GCC diagnostic push
835#pragma GCC diagnostic ignored "-Wignored-qualifiers"
836 template <
typename... _Args>
837 struct __untag_result<const void(*)(_Args...)>
839 {
using element_type = void(*)(_Args...); };
840#pragma GCC diagnostic pop
842 template <
typename... _Args>
843 struct __untag_result<__variant_cookie(*)(_Args...)>
845 {
using element_type = void(*)(_Args...); };
847 template <
typename... _Args>
848 struct __untag_result<__variant_idx_cookie(*)(_Args...)>
850 {
using element_type = void(*)(_Args...); };
852 template <
typename _Res,
typename... _Args>
853 struct __untag_result<__deduce_visit_result<_Res>(*)(_Args...)>
855 {
using element_type = _Res(*)(_Args...); };
857 using __result_is_deduced = __untag_result<_Tp>;
859 constexpr const typename __untag_result<_Tp>::element_type&
863 typename __untag_result<_Tp>::element_type _M_data;
867 template<
typename _Ret,
869 typename... _Variants,
870 size_t __first,
size_t... __rest>
871 struct _Multi_array<_Ret(*)(_Visitor, _Variants...), __first, __rest...>
873 static constexpr size_t __index =
874 sizeof...(_Variants) -
sizeof...(__rest) - 1;
876 using _Variant =
typename _Nth_type<__index, _Variants...>::type;
878 static constexpr int __do_cookie =
879 __extra_visit_slot_needed<_Ret, _Variant> ? 1 : 0;
881 using _Tp = _Ret(*)(_Visitor, _Variants...);
883 template<
typename... _Args>
884 constexpr decltype(
auto)
885 _M_access(
size_t __first_index, _Args... __rest_indices)
const
887 return _M_arr[__first_index + __do_cookie]
888 ._M_access(__rest_indices...);
891 _Multi_array<_Tp, __rest...> _M_arr[__first + __do_cookie];
921 template<
typename _Array_type,
typename _Index_seq>
922 struct __gen_vtable_impl;
931 template<
typename _Result_type,
typename _Visitor,
size_t... __dimensions,
932 typename... _Variants,
size_t... __indices>
933 struct __gen_vtable_impl<
934 _Multi_array<_Result_type (*)(_Visitor, _Variants...), __dimensions...>,
939 _Variants...>::type>;
941 _Multi_array<_Result_type (*)(_Visitor, _Variants...),
944 static constexpr _Array_type
947 _Array_type __vtable{};
953 template<
size_t... __var_indices>
954 static constexpr void
955 _S_apply_all_alts(_Array_type& __vtable,
958 if constexpr (__extra_visit_slot_needed<_Result_type, _Next>)
959 (_S_apply_single_alt<true, __var_indices>(
960 __vtable._M_arr[__var_indices + 1],
961 &(__vtable._M_arr[0])), ...);
963 (_S_apply_single_alt<false, __var_indices>(
964 __vtable._M_arr[__var_indices]), ...);
967 template<
bool __do_cookie,
size_t __index,
typename _Tp>
968 static constexpr void
969 _S_apply_single_alt(_Tp& __element, _Tp* __cookie_element =
nullptr)
971 if constexpr (__do_cookie)
973 __element = __gen_vtable_impl<
976 *__cookie_element = __gen_vtable_impl<
982 auto __tmp_element = __gen_vtable_impl<
985 static_assert(is_same_v<_Tp,
decltype(__tmp_element)>,
986 "std::visit requires the visitor to have the same "
987 "return type for all alternatives of a variant");
988 __element = __tmp_element;
996 template<
typename _Result_type,
typename _Visitor,
typename... _Variants,
998 struct __gen_vtable_impl<
999 _Multi_array<_Result_type (*)(_Visitor, _Variants...)>,
1003 _Multi_array<_Result_type (*)(_Visitor, _Variants...)>;
1005 template<
size_t __index,
typename _Variant>
1006 static constexpr decltype(
auto)
1007 __element_by_index_or_cookie(_Variant&& __var)
noexcept
1009 if constexpr (__index != variant_npos)
1010 return __variant::__get<__index>(std::forward<_Variant>(__var));
1012 return __variant_cookie{};
1015 static constexpr decltype(
auto)
1016 __visit_invoke(_Visitor&& __visitor, _Variants... __vars)
1018 if constexpr (is_same_v<_Result_type, __variant_idx_cookie>)
1022 __element_by_index_or_cookie<__indices>(
1023 std::forward<_Variants>(__vars))...,
1024 integral_constant<size_t, __indices>()...);
1025 else if constexpr (is_same_v<_Result_type, __variant_cookie>)
1028 __element_by_index_or_cookie<__indices>(
1029 std::forward<_Variants>(__vars))...);
1030 else if constexpr (_Array_type::__result_is_deduced::value)
1033 __element_by_index_or_cookie<__indices>(
1034 std::forward<_Variants>(__vars))...);
1036 return std::__invoke_r<_Result_type>(
1037 std::forward<_Visitor>(__visitor),
1038 __variant::__get<__indices>(std::forward<_Variants>(__vars))...);
1041 static constexpr auto
1044 if constexpr (_Array_type::__result_is_deduced::value)
1046 constexpr bool __visit_ret_type_mismatch =
1047 !is_same_v<
typename _Result_type::type,
1048 decltype(__visit_invoke(std::declval<_Visitor>(),
1049 std::declval<_Variants>()...))>;
1050 if constexpr (__visit_ret_type_mismatch)
1052 struct __cannot_match {};
1053 return __cannot_match{};
1056 return _Array_type{&__visit_invoke};
1059 return _Array_type{&__visit_invoke};
1063 template<
typename _Result_type,
typename _Visitor,
typename... _Variants>
1067 _Multi_array<_Result_type (*)(_Visitor, _Variants...),
1068 variant_size_v<remove_reference_t<_Variants>>...>;
1070 static constexpr _Array_type _S_vtable
1071 = __gen_vtable_impl<_Array_type, std::index_sequence<>>::_S_apply();
1074 template<
size_t _Np,
typename _Tp>
1075 struct _Base_dedup :
public _Tp { };
1077 template<
typename _Variant,
typename __indices>
1078 struct _Variant_hash_base;
1080 template<
typename... _Types,
size_t... __indices>
1081 struct _Variant_hash_base<variant<_Types...>,
1083 : _Base_dedup<__indices, __poison_hash<remove_const_t<_Types>>>... { };
1086 template<
size_t _Np,
typename _Variant,
1087 typename _AsV =
decltype(__variant::__as(std::declval<_Variant>())),
1088 typename _Tp = variant_alternative_t<_Np, remove_reference_t<_AsV>>>
1090 = __conditional_t<is_lvalue_reference_v<_Variant>, _Tp&, _Tp&&>;
1093 template<
typename _Visitor,
typename... _Variants>
1094 using __visit_result_t
1095 = invoke_result_t<_Visitor, __get_t<0, _Variants>...>;
1097 template<
typename _Tp,
typename... _Types>
1098 constexpr inline bool __same_types = (is_same_v<_Tp, _Types> && ...);
1100 template <
typename _Visitor,
typename _Variant,
size_t... _Idxs>
1103 return __same_types<
1104 invoke_result_t<_Visitor, __get_t<_Idxs, _Variant>>...
1111 template<
typename _Tp,
typename... _Types>
1113 holds_alternative(
const variant<_Types...>& __v)
noexcept
1115 static_assert(__detail::__variant::__exactly_once<_Tp, _Types...>,
1116 "T must occur exactly once in alternatives");
1117 return __v.index() == std::__find_uniq_type_in_pack<_Tp, _Types...>();
1120 template<
typename _Tp,
typename... _Types>
1122 get(variant<_Types...>& __v)
1124 static_assert(__detail::__variant::__exactly_once<_Tp, _Types...>,
1125 "T must occur exactly once in alternatives");
1126 static_assert(!is_void_v<_Tp>,
"_Tp must not be void");
1127 constexpr size_t __n = std::__find_uniq_type_in_pack<_Tp, _Types...>();
1128 return std::get<__n>(__v);
1131 template<
typename _Tp,
typename... _Types>
1133 get(variant<_Types...>&& __v)
1135 static_assert(__detail::__variant::__exactly_once<_Tp, _Types...>,
1136 "T must occur exactly once in alternatives");
1137 static_assert(!is_void_v<_Tp>,
"_Tp must not be void");
1138 constexpr size_t __n = std::__find_uniq_type_in_pack<_Tp, _Types...>();
1142 template<
typename _Tp,
typename... _Types>
1143 constexpr const _Tp&
1144 get(
const variant<_Types...>& __v)
1146 static_assert(__detail::__variant::__exactly_once<_Tp, _Types...>,
1147 "T must occur exactly once in alternatives");
1148 static_assert(!is_void_v<_Tp>,
"_Tp must not be void");
1149 constexpr size_t __n = std::__find_uniq_type_in_pack<_Tp, _Types...>();
1150 return std::get<__n>(__v);
1153 template<
typename _Tp,
typename... _Types>
1154 constexpr const _Tp&&
1155 get(
const variant<_Types...>&& __v)
1157 static_assert(__detail::__variant::__exactly_once<_Tp, _Types...>,
1158 "T must occur exactly once in alternatives");
1159 static_assert(!is_void_v<_Tp>,
"_Tp must not be void");
1160 constexpr size_t __n = std::__find_uniq_type_in_pack<_Tp, _Types...>();
1164 template<
size_t _Np,
typename... _Types>
1165 constexpr add_pointer_t<variant_alternative_t<_Np, variant<_Types...>>>
1166 get_if(variant<_Types...>* __ptr)
noexcept
1168 using _Alternative_type = variant_alternative_t<_Np, variant<_Types...>>;
1169 static_assert(_Np <
sizeof...(_Types),
1170 "The index must be in [0, number of alternatives)");
1171 static_assert(!is_void_v<_Alternative_type>,
"_Tp must not be void");
1172 if (__ptr && __ptr->index() == _Np)
1177 template<
size_t _Np,
typename... _Types>
1179 add_pointer_t<
const variant_alternative_t<_Np, variant<_Types...>>>
1180 get_if(
const variant<_Types...>* __ptr)
noexcept
1182 using _Alternative_type = variant_alternative_t<_Np, variant<_Types...>>;
1183 static_assert(_Np <
sizeof...(_Types),
1184 "The index must be in [0, number of alternatives)");
1185 static_assert(!is_void_v<_Alternative_type>,
"_Tp must not be void");
1186 if (__ptr && __ptr->index() == _Np)
1191 template<
typename _Tp,
typename... _Types>
1192 constexpr add_pointer_t<_Tp>
1193 get_if(variant<_Types...>* __ptr)
noexcept
1195 static_assert(__detail::__variant::__exactly_once<_Tp, _Types...>,
1196 "T must occur exactly once in alternatives");
1197 static_assert(!is_void_v<_Tp>,
"_Tp must not be void");
1198 constexpr size_t __n = std::__find_uniq_type_in_pack<_Tp, _Types...>();
1199 return std::get_if<__n>(__ptr);
1202 template<
typename _Tp,
typename... _Types>
1203 constexpr add_pointer_t<const _Tp>
1204 get_if(
const variant<_Types...>* __ptr)
noexcept
1206 static_assert(__detail::__variant::__exactly_once<_Tp, _Types...>,
1207 "T must occur exactly once in alternatives");
1208 static_assert(!is_void_v<_Tp>,
"_Tp must not be void");
1209 constexpr size_t __n = std::__find_uniq_type_in_pack<_Tp, _Types...>();
1210 return std::get_if<__n>(__ptr);
1213 struct monostate { };
1215#define _VARIANT_RELATION_FUNCTION_TEMPLATE(__OP, __NAME) \
1216 template<typename... _Types> \
1217 constexpr bool operator __OP(const variant<_Types...>& __lhs, \
1218 const variant<_Types...>& __rhs) \
1220 bool __ret = true; \
1221 __detail::__variant::__raw_idx_visit( \
1222 [&__ret, &__lhs] (auto&& __rhs_mem, auto __rhs_index) mutable \
1224 if constexpr (__rhs_index != variant_npos) \
1226 if (__lhs.index() == __rhs_index) \
1228 auto& __this_mem = std::get<__rhs_index>(__lhs); \
1229 __ret = __this_mem __OP __rhs_mem; \
1232 __ret = (__lhs.index() + 1) __OP (__rhs_index + 1); \
1235 __ret = (__lhs.index() + 1) __OP (__rhs_index + 1); \
1240 _VARIANT_RELATION_FUNCTION_TEMPLATE(<, less)
1241 _VARIANT_RELATION_FUNCTION_TEMPLATE(<=, less_equal)
1242 _VARIANT_RELATION_FUNCTION_TEMPLATE(==, equal)
1243 _VARIANT_RELATION_FUNCTION_TEMPLATE(!=, not_equal)
1244 _VARIANT_RELATION_FUNCTION_TEMPLATE(>=, greater_equal)
1245 _VARIANT_RELATION_FUNCTION_TEMPLATE(>, greater)
1247#undef _VARIANT_RELATION_FUNCTION_TEMPLATE
1249 constexpr bool operator==(monostate, monostate)
noexcept {
return true; }
1251#ifdef __cpp_lib_three_way_comparison
1252 template<
typename... _Types>
1253 requires (three_way_comparable<_Types> && ...)
1255 common_comparison_category_t<compare_three_way_result_t<_Types>...>
1256 operator<=>(
const variant<_Types...>& __v,
const variant<_Types...>& __w)
1258 common_comparison_category_t<compare_three_way_result_t<_Types>...> __ret
1259 = strong_ordering::equal;
1261 __detail::__variant::__raw_idx_visit(
1262 [&__ret, &__v] (
auto&& __w_mem,
auto __w_index)
mutable
1264 if constexpr (__w_index != variant_npos)
1266 if (__v.index() == __w_index)
1268 auto& __this_mem = std::get<__w_index>(__v);
1269 __ret = __this_mem <=> __w_mem;
1273 __ret = (__v.index() + 1) <=> (__w_index + 1);
1278 constexpr strong_ordering
1279 operator<=>(monostate, monostate)
noexcept {
return strong_ordering::equal; }
1281 constexpr bool operator!=(monostate, monostate)
noexcept {
return false; }
1282 constexpr bool operator<(monostate, monostate)
noexcept {
return false; }
1283 constexpr bool operator>(monostate, monostate)
noexcept {
return false; }
1284 constexpr bool operator<=(monostate, monostate)
noexcept {
return true; }
1285 constexpr bool operator>=(monostate, monostate)
noexcept {
return true; }
1288 template<
typename _Visitor,
typename... _Variants>
1289 constexpr __detail::__variant::__visit_result_t<_Visitor, _Variants...>
1290 visit(_Visitor&&, _Variants&&...);
1292 template<
typename... _Types>
1293 _GLIBCXX20_CONSTEXPR
1294 inline enable_if_t<(is_move_constructible_v<_Types> && ...)
1295 && (is_swappable_v<_Types> && ...)>
1296 swap(variant<_Types...>& __lhs, variant<_Types...>& __rhs)
1297 noexcept(
noexcept(__lhs.swap(__rhs)))
1298 { __lhs.swap(__rhs); }
1300 template<
typename... _Types>
1301 enable_if_t<!((is_move_constructible_v<_Types> && ...)
1302 && (is_swappable_v<_Types> && ...))>
1303 swap(variant<_Types...>&, variant<_Types...>&) =
delete;
1305 class bad_variant_access :
public exception
1308 bad_variant_access() noexcept { }
1310 const char* what() const noexcept
override
1311 {
return _M_reason; }
1314 bad_variant_access(
const char* __reason) noexcept : _M_reason(__reason) { }
1317 const char* _M_reason =
"bad variant access";
1319 friend void __throw_bad_variant_access(
const char* __what);
1324 __throw_bad_variant_access(
const char* __what)
1325 { _GLIBCXX_THROW_OR_ABORT(bad_variant_access(__what)); }
1328 __throw_bad_variant_access(
bool __valueless)
1330 if (__valueless) [[__unlikely__]]
1331 __throw_bad_variant_access(
"std::get: variant is valueless");
1333 __throw_bad_variant_access(
"std::get: wrong index for variant");
1336 template<
typename... _Types>
1338 :
private __detail::__variant::_Variant_base<_Types...>,
1339 private _Enable_default_constructor<
1340 __detail::__variant::_Traits<_Types...>::_S_default_ctor,
1341 variant<_Types...>>,
1342 private _Enable_copy_move<
1343 __detail::__variant::_Traits<_Types...>::_S_copy_ctor,
1344 __detail::__variant::_Traits<_Types...>::_S_copy_assign,
1345 __detail::__variant::_Traits<_Types...>::_S_move_ctor,
1346 __detail::__variant::_Traits<_Types...>::_S_move_assign,
1350 template <
typename... _UTypes,
typename _Tp>
1351 friend _GLIBCXX20_CONSTEXPR
decltype(
auto)
1352 __variant_cast(_Tp&&);
1354 static_assert(
sizeof...(_Types) > 0,
1355 "variant must have at least one alternative");
1356 static_assert(!(std::is_reference_v<_Types> || ...),
1357 "variant must have no reference alternative");
1358 static_assert(!(std::is_void_v<_Types> || ...),
1359 "variant must have no void alternative");
1361 using _Base = __detail::__variant::_Variant_base<_Types...>;
1362 using _Default_ctor_enabler =
1363 _Enable_default_constructor<
1364 __detail::__variant::_Traits<_Types...>::_S_default_ctor,
1365 variant<_Types...>>;
1367 template<
typename _Tp>
1368 static constexpr bool __not_self
1369 = !is_same_v<__remove_cvref_t<_Tp>, variant>;
1371 template<
typename _Tp>
1372 static constexpr bool
1373 __exactly_once = __detail::__variant::__exactly_once<_Tp, _Types...>;
1375 template<
typename _Tp>
1376 static constexpr size_t __accepted_index
1377 = __detail::__variant::__accepted_index<_Tp, variant>;
1379 template<
size_t _Np,
typename =
enable_if_t<(_Np <
sizeof...(_Types))>>
1380 using __to_type =
typename _Nth_type<_Np, _Types...>::type;
1382 template<
typename _Tp,
typename = enable_if_t<__not_self<_Tp>>>
1383 using __accepted_type = __to_type<__accepted_index<_Tp>>;
1385 template<
typename _Tp>
1386 static constexpr size_t __index_of
1387 = std::__find_uniq_type_in_pack<_Tp, _Types...>();
1389 using _Traits = __detail::__variant::_Traits<_Types...>;
1391 template<
typename _Tp>
1393 template<
typename _Tp>
1394 struct __is_in_place_tag<in_place_type_t<_Tp>> :
true_type { };
1395 template<
size_t _Np>
1396 struct __is_in_place_tag<in_place_index_t<_Np>> :
true_type { };
1398 template<
typename _Tp>
1399 static constexpr bool __not_in_place_tag
1400 = !__is_in_place_tag<__remove_cvref_t<_Tp>>::value;
1403 variant() =
default;
1404 variant(
const variant& __rhs) =
default;
1405 variant(variant&&) =
default;
1406 variant& operator=(
const variant&) =
default;
1407 variant& operator=(variant&&) =
default;
1408 _GLIBCXX20_CONSTEXPR ~variant() =
default;
1410 template<
typename _Tp,
1413 typename _Tj = __accepted_type<_Tp&&>,
1415 && is_constructible_v<_Tj, _Tp>>>
1418 noexcept(is_nothrow_constructible_v<_Tj, _Tp>)
1419 : variant(in_place_index<__accepted_index<_Tp>>,
1423 template<
typename _Tp,
typename... _Args,
1424 typename = enable_if_t<__exactly_once<_Tp>
1425 && is_constructible_v<_Tp, _Args...>>>
1427 variant(in_place_type_t<_Tp>, _Args&&... __args)
1428 : variant(in_place_index<__index_of<_Tp>>,
1432 template<
typename _Tp,
typename _Up,
typename... _Args,
1433 typename = enable_if_t<__exactly_once<_Tp>
1434 && is_constructible_v<_Tp,
1435 initializer_list<_Up>&, _Args...>>>
1437 variant(in_place_type_t<_Tp>, initializer_list<_Up> __il,
1439 : variant(in_place_index<__index_of<_Tp>>, __il,
1443 template<
size_t _Np,
typename... _Args,
1444 typename _Tp = __to_type<_Np>,
1445 typename =
enable_if_t<is_constructible_v<_Tp, _Args...>>>
1447 variant(in_place_index_t<_Np>, _Args&&... __args)
1448 : _Base(in_place_index<_Np>,
std::
forward<_Args>(__args)...),
1449 _Default_ctor_enabler(_Enable_default_constructor_tag{})
1452 template<
size_t _Np,
typename _Up,
typename... _Args,
1453 typename _Tp = __to_type<_Np>,
1455 initializer_list<_Up>&,
1458 variant(in_place_index_t<_Np>, initializer_list<_Up> __il,
1460 : _Base(in_place_index<_Np>, __il,
std::
forward<_Args>(__args)...),
1461 _Default_ctor_enabler(_Enable_default_constructor_tag{})
1464 template<
typename _Tp>
1465 _GLIBCXX20_CONSTEXPR
1466 enable_if_t<__exactly_once<__accepted_type<_Tp&&>>
1467 && is_constructible_v<__accepted_type<_Tp&&>, _Tp>
1468 && is_assignable_v<__accepted_type<_Tp&&>&, _Tp>,
1470 operator=(_Tp&& __rhs)
1471 noexcept(is_nothrow_assignable_v<__accepted_type<_Tp&&>&, _Tp>
1472 && is_nothrow_constructible_v<__accepted_type<_Tp&&>, _Tp>)
1474 constexpr auto __index = __accepted_index<_Tp>;
1475 if (index() == __index)
1476 std::get<__index>(*
this) = std::forward<_Tp>(__rhs);
1479 using _Tj = __accepted_type<_Tp&&>;
1480 if constexpr (is_nothrow_constructible_v<_Tj, _Tp>
1481 || !is_nothrow_move_constructible_v<_Tj>)
1482 this->emplace<__index>(std::forward<_Tp>(__rhs));
1486 this->emplace<__index>(_Tj(std::forward<_Tp>(__rhs)));
1491 template<
typename _Tp,
typename... _Args>
1492 _GLIBCXX20_CONSTEXPR
1493 enable_if_t<is_constructible_v<_Tp, _Args...> && __exactly_once<_Tp>,
1495 emplace(_Args&&... __args)
1497 constexpr size_t __index = __index_of<_Tp>;
1498 return this->emplace<__index>(std::forward<_Args>(__args)...);
1501 template<
typename _Tp,
typename _Up,
typename... _Args>
1502 _GLIBCXX20_CONSTEXPR
1503 enable_if_t<is_constructible_v<_Tp, initializer_list<_Up>&, _Args...>
1504 && __exactly_once<_Tp>,
1506 emplace(initializer_list<_Up> __il, _Args&&... __args)
1508 constexpr size_t __index = __index_of<_Tp>;
1509 return this->emplace<__index>(__il, std::forward<_Args>(__args)...);
1512 template<
size_t _Np,
typename... _Args>
1513 _GLIBCXX20_CONSTEXPR
1514 enable_if_t<is_constructible_v<__to_type<_Np>, _Args...>,
1516 emplace(_Args&&... __args)
1518 namespace __variant = std::__detail::__variant;
1519 using type =
typename _Nth_type<_Np, _Types...>::type;
1522 if constexpr (is_nothrow_constructible_v<type, _Args...>)
1524 __variant::__emplace<_Np>(*
this, std::forward<_Args>(__args)...);
1526 else if constexpr (is_scalar_v<type>)
1529 const type __tmp(std::forward<_Args>(__args)...);
1531 __variant::__emplace<_Np>(*
this, __tmp);
1533 else if constexpr (__variant::_Never_valueless_alt<type>()
1534 && _Traits::_S_move_assign)
1537 variant __tmp(in_place_index<_Np>,
1538 std::forward<_Args>(__args)...);
1546 __variant::__emplace<_Np>(*
this, std::forward<_Args>(__args)...);
1548 return std::get<_Np>(*
this);
1551 template<
size_t _Np,
typename _Up,
typename... _Args>
1552 _GLIBCXX20_CONSTEXPR
1553 enable_if_t<is_constructible_v<__to_type<_Np>,
1554 initializer_list<_Up>&, _Args...>,
1556 emplace(initializer_list<_Up> __il, _Args&&... __args)
1558 namespace __variant = std::__detail::__variant;
1559 using type =
typename _Nth_type<_Np, _Types...>::type;
1562 if constexpr (is_nothrow_constructible_v<type,
1563 initializer_list<_Up>&,
1566 __variant::__emplace<_Np>(*
this, __il,
1567 std::forward<_Args>(__args)...);
1569 else if constexpr (__variant::_Never_valueless_alt<type>()
1570 && _Traits::_S_move_assign)
1573 variant __tmp(in_place_index<_Np>, __il,
1574 std::forward<_Args>(__args)...);
1582 __variant::__emplace<_Np>(*
this, __il,
1583 std::forward<_Args>(__args)...);
1585 return std::get<_Np>(*
this);
1588 template<
size_t _Np,
typename... _Args>
1589 enable_if_t<!(_Np <
sizeof...(_Types))> emplace(_Args&&...) =
delete;
1591 template<
typename _Tp,
typename... _Args>
1592 enable_if_t<!__exactly_once<_Tp>> emplace(_Args&&...) =
delete;
1594 constexpr bool valueless_by_exception() const noexcept
1595 {
return !this->_M_valid(); }
1597 constexpr size_t index() const noexcept
1599 using __index_type =
typename _Base::__index_type;
1600 if constexpr (__detail::__variant::__never_valueless<_Types...>())
1601 return this->_M_index;
1602 else if constexpr (
sizeof...(_Types) <= __index_type(-1) / 2)
1603 return make_signed_t<__index_type>(this->_M_index);
1605 return size_t(__index_type(this->_M_index + 1)) - 1;
1608 _GLIBCXX20_CONSTEXPR
1610 swap(variant& __rhs)
1611 noexcept((__is_nothrow_swappable<_Types>::value && ...)
1612 && is_nothrow_move_constructible_v<variant>)
1614 static_assert((is_move_constructible_v<_Types> && ...));
1617 if (__rhs.valueless_by_exception()) [[__unlikely__]]
1619 if (!this->valueless_by_exception()) [[__likely__]]
1624 namespace __variant = __detail::__variant;
1626 __variant::__raw_idx_visit(
1627 [
this, &__rhs](
auto&& __rhs_mem,
auto __rhs_index)
mutable
1629 constexpr size_t __j = __rhs_index;
1630 if constexpr (__j != variant_npos)
1632 if (this->index() == __j)
1635 swap(std::get<__j>(*
this), __rhs_mem);
1641 if constexpr (_Traits::_S_trivial_move_assign)
1644 __variant::__raw_idx_visit(
1645 [&__rhs](
auto&& __this_mem,
auto __this_index)
mutable
1647 constexpr size_t __k = __this_index;
1648 if constexpr (__k != variant_npos)
1649 __variant::__emplace<__k>(__rhs,
1653 __variant::__emplace<__j>(*
this,
std::move(__tmp));
1659#if defined(__clang__) && __clang_major__ <= 7
1665 template<
size_t _Np,
typename _Vp>
1666 friend constexpr decltype(
auto)
1667 __detail::__variant::__get(_Vp&& __v)
noexcept;
1669#define _VARIANT_RELATION_FUNCTION_TEMPLATE(__OP) \
1670 template<typename... _Tp> \
1671 friend constexpr bool \
1672 operator __OP(const variant<_Tp...>& __lhs, \
1673 const variant<_Tp...>& __rhs);
1675 _VARIANT_RELATION_FUNCTION_TEMPLATE(<)
1676 _VARIANT_RELATION_FUNCTION_TEMPLATE(<=)
1677 _VARIANT_RELATION_FUNCTION_TEMPLATE(==)
1678 _VARIANT_RELATION_FUNCTION_TEMPLATE(!=)
1679 _VARIANT_RELATION_FUNCTION_TEMPLATE(>=)
1680 _VARIANT_RELATION_FUNCTION_TEMPLATE(>)
1682#undef _VARIANT_RELATION_FUNCTION_TEMPLATE
1685 template<
size_t _Np,
typename... _Types>
1686 constexpr variant_alternative_t<_Np, variant<_Types...>>&
1687 get(variant<_Types...>& __v)
1689 static_assert(_Np <
sizeof...(_Types),
1690 "The index must be in [0, number of alternatives)");
1691 if (__v.index() != _Np)
1692 __throw_bad_variant_access(__v.valueless_by_exception());
1693 return __detail::__variant::__get<_Np>(__v);
1696 template<
size_t _Np,
typename... _Types>
1697 constexpr variant_alternative_t<_Np, variant<_Types...>>&&
1698 get(variant<_Types...>&& __v)
1700 static_assert(_Np <
sizeof...(_Types),
1701 "The index must be in [0, number of alternatives)");
1702 if (__v.index() != _Np)
1703 __throw_bad_variant_access(__v.valueless_by_exception());
1704 return __detail::__variant::__get<_Np>(
std::move(__v));
1707 template<
size_t _Np,
typename... _Types>
1708 constexpr const variant_alternative_t<_Np, variant<_Types...>>&
1709 get(
const variant<_Types...>& __v)
1711 static_assert(_Np <
sizeof...(_Types),
1712 "The index must be in [0, number of alternatives)");
1713 if (__v.index() != _Np)
1714 __throw_bad_variant_access(__v.valueless_by_exception());
1715 return __detail::__variant::__get<_Np>(__v);
1718 template<
size_t _Np,
typename... _Types>
1719 constexpr const variant_alternative_t<_Np, variant<_Types...>>&&
1720 get(
const variant<_Types...>&& __v)
1722 static_assert(_Np <
sizeof...(_Types),
1723 "The index must be in [0, number of alternatives)");
1724 if (__v.index() != _Np)
1725 __throw_bad_variant_access(__v.valueless_by_exception());
1726 return __detail::__variant::__get<_Np>(
std::move(__v));
1730 template<
typename _Result_type,
typename _Visitor,
typename... _Variants>
1731 constexpr decltype(
auto)
1732 __do_visit(_Visitor&& __visitor, _Variants&&... __variants)
1735 if constexpr (
sizeof...(_Variants) == 0)
1737 if constexpr (is_void_v<_Result_type>)
1738 return (
void) std::forward<_Visitor>(__visitor)();
1740 return std::forward<_Visitor>(__visitor)();
1744 constexpr size_t __max = 11;
1747 using _V0 =
typename _Nth_type<0, _Variants...>::type;
1749 constexpr auto __n = variant_size_v<remove_reference_t<_V0>>;
1751 if constexpr (
sizeof...(_Variants) > 1 || __n > __max)
1754 constexpr auto& __vtable = __detail::__variant::__gen_vtable<
1755 _Result_type, _Visitor&&, _Variants&&...>::_S_vtable;
1757 auto __func_ptr = __vtable._M_access(__variants.index()...);
1758 return (*__func_ptr)(std::forward<_Visitor>(__visitor),
1759 std::forward<_Variants>(__variants)...);
1765 = [](_V0& __v, ...) -> _V0& {
return __v; }(__variants...);
1767 using __detail::__variant::_Multi_array;
1768 using __detail::__variant::__gen_vtable_impl;
1769 using _Ma = _Multi_array<_Result_type (*)(_Visitor&&, _V0&&)>;
1771#ifdef _GLIBCXX_DEBUG
1772# define _GLIBCXX_VISIT_UNREACHABLE __builtin_trap
1774# define _GLIBCXX_VISIT_UNREACHABLE __builtin_unreachable
1777#define _GLIBCXX_VISIT_CASE(N) \
1780 if constexpr (N < __n) \
1782 return __gen_vtable_impl<_Ma, index_sequence<N>>:: \
1783 __visit_invoke(std::forward<_Visitor>(__visitor), \
1784 std::forward<_V0>(__v0)); \
1786 else _GLIBCXX_VISIT_UNREACHABLE(); \
1789 switch (__v0.index())
1791 _GLIBCXX_VISIT_CASE(0)
1792 _GLIBCXX_VISIT_CASE(1)
1793 _GLIBCXX_VISIT_CASE(2)
1794 _GLIBCXX_VISIT_CASE(3)
1795 _GLIBCXX_VISIT_CASE(4)
1796 _GLIBCXX_VISIT_CASE(5)
1797 _GLIBCXX_VISIT_CASE(6)
1798 _GLIBCXX_VISIT_CASE(7)
1799 _GLIBCXX_VISIT_CASE(8)
1800 _GLIBCXX_VISIT_CASE(9)
1801 _GLIBCXX_VISIT_CASE(10)
1803 using __detail::__variant::__variant_idx_cookie;
1804 using __detail::__variant::__variant_cookie;
1805 if constexpr (is_same_v<_Result_type, __variant_idx_cookie>
1806 || is_same_v<_Result_type, __variant_cookie>)
1808 using _Npos = index_sequence<variant_npos>;
1809 return __gen_vtable_impl<_Ma, _Npos>::
1810 __visit_invoke(std::forward<_Visitor>(__visitor),
1811 std::forward<_V0>(__v0));
1814 _GLIBCXX_VISIT_UNREACHABLE();
1816 _GLIBCXX_VISIT_UNREACHABLE();
1818#undef _GLIBCXX_VISIT_CASE
1819#undef _GLIBCXX_VISIT_UNREACHABLE
1825 template<
typename _Visitor,
typename... _Variants>
1826 constexpr __detail::__variant::__visit_result_t<_Visitor, _Variants...>
1827 visit(_Visitor&& __visitor, _Variants&&... __variants)
1829 namespace __variant = std::__detail::__variant;
1831 if ((__variant::__as(__variants).valueless_by_exception() || ...))
1832 __throw_bad_variant_access(
"std::visit: variant is valueless");
1835 = __detail::__variant::__visit_result_t<_Visitor, _Variants...>;
1837 using _Tag = __detail::__variant::__deduce_visit_result<_Result_type>;
1839 if constexpr (
sizeof...(_Variants) == 1)
1841 using _Vp =
decltype(__variant::__as(std::declval<_Variants>()...));
1843 constexpr bool __visit_rettypes_match = __detail::__variant::
1844 __check_visitor_results<_Visitor, _Vp>(
1846 if constexpr (!__visit_rettypes_match)
1848 static_assert(__visit_rettypes_match,
1849 "std::visit requires the visitor to have the same "
1850 "return type for all alternatives of a variant");
1854 return std::__do_visit<_Tag>(
1855 std::forward<_Visitor>(__visitor),
1856 static_cast<_Vp
>(__variants)...);
1859 return std::__do_visit<_Tag>(
1860 std::forward<_Visitor>(__visitor),
1861 __variant::__as(std::forward<_Variants>(__variants))...);
1864#if __cplusplus > 201703L
1865 template<
typename _Res,
typename _Visitor,
typename... _Variants>
1867 visit(_Visitor&& __visitor, _Variants&&... __variants)
1869 namespace __variant = std::__detail::__variant;
1871 if ((__variant::__as(__variants).valueless_by_exception() || ...))
1872 __throw_bad_variant_access(
"std::visit<R>: variant is valueless");
1874 return std::__do_visit<_Res>(std::forward<_Visitor>(__visitor),
1875 __variant::__as(std::forward<_Variants>(__variants))...);
1880 template<bool,
typename... _Types>
1881 struct __variant_hash_call_base_impl
1884 operator()(
const variant<_Types...>& __t)
const
1885 noexcept((is_nothrow_invocable_v<hash<decay_t<_Types>>, _Types> && ...))
1888 __detail::__variant::__raw_visit(
1889 [&__t, &__ret](
auto&& __t_mem)
mutable
1891 using _Type = __remove_cvref_t<
decltype(__t_mem)>;
1892 if constexpr (!is_same_v<_Type,
1893 __detail::__variant::__variant_cookie>)
1903 template<
typename... _Types>
1904 struct __variant_hash_call_base_impl<false, _Types...> {};
1906 template<
typename... _Types>
1907 using __variant_hash_call_base =
1908 __variant_hash_call_base_impl<(__poison_hash<remove_const_t<_Types>>::
1909 __enable_hash_call &&...), _Types...>;
1912 template<
typename... _Types>
1913 struct hash<variant<_Types...>>
1914 :
private __detail::__variant::_Variant_hash_base<
1915 variant<_Types...>, std::index_sequence_for<_Types...>>,
1916 public __variant_hash_call_base<_Types...>
1918 using result_type [[__deprecated__]] = size_t;
1919 using argument_type [[__deprecated__]] = variant<_Types...>;
1923 struct hash<monostate>
1925 using result_type [[__deprecated__]] = size_t;
1926 using argument_type [[__deprecated__]] = monostate;
1929 operator()(
const monostate&)
const noexcept
1931 constexpr size_t __magic_monostate_hash = -7777;
1932 return __magic_monostate_hash;
1936 template<
typename... _Types>
1937 struct __is_fast_hash<hash<variant<_Types...>>>
1941_GLIBCXX_END_NAMESPACE_VERSION
typename remove_reference< _Tp >::type remove_reference_t
Alias template for remove_reference.
integral_constant< bool, __v > bool_constant
Alias template for compile-time boolean constant types.
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.
integral_constant< bool, false > false_type
The type used as a compile-time boolean with false value.
typename add_pointer< _Tp >::type add_pointer_t
Alias template for add_pointer.
typename enable_if< _Cond, _Tp >::type enable_if_t
Alias template for enable_if.
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...
constexpr std::remove_reference< _Tp >::type && move(_Tp &&__t) noexcept
Convert a value to an rvalue.
constexpr __invoke_result< _Callable, _Args... >::type __invoke(_Callable &&__fn, _Args &&... __args) noexcept(__is_nothrow_invocable< _Callable, _Args... >::value)
Invoke a callable object.
void swap(any &__x, any &__y) noexcept
Exchange the states of two any objects.
constexpr _Tp * __addressof(_Tp &__r) noexcept
Same as C++11 std::addressof.
constexpr _Tp && forward(typename std::remove_reference< _Tp >::type &__t) noexcept
Forward an lvalue.
ISO C++ entities toplevel namespace is std.
make_integer_sequence< size_t, _Num > make_index_sequence
Alias template make_index_sequence.
constexpr void _Construct(_Tp *__p, _Args &&... __args)
integer_sequence< size_t, _Idx... > index_sequence
Alias template index_sequence.
Primary class template hash.