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 template <
typename... _Args>
835 struct __untag_result<const void(*)(_Args...)>
837 {
using element_type = void(*)(_Args...); };
839 template <
typename... _Args>
840 struct __untag_result<__variant_cookie(*)(_Args...)>
842 {
using element_type = void(*)(_Args...); };
844 template <
typename... _Args>
845 struct __untag_result<__variant_idx_cookie(*)(_Args...)>
847 {
using element_type = void(*)(_Args...); };
849 template <
typename _Res,
typename... _Args>
850 struct __untag_result<__deduce_visit_result<_Res>(*)(_Args...)>
852 {
using element_type = _Res(*)(_Args...); };
854 using __result_is_deduced = __untag_result<_Tp>;
856 constexpr const typename __untag_result<_Tp>::element_type&
860 typename __untag_result<_Tp>::element_type _M_data;
864 template<
typename _Ret,
866 typename... _Variants,
867 size_t __first,
size_t... __rest>
868 struct _Multi_array<_Ret(*)(_Visitor, _Variants...), __first, __rest...>
870 static constexpr size_t __index =
871 sizeof...(_Variants) -
sizeof...(__rest) - 1;
873 using _Variant =
typename _Nth_type<__index, _Variants...>::type;
875 static constexpr int __do_cookie =
876 __extra_visit_slot_needed<_Ret, _Variant> ? 1 : 0;
878 using _Tp = _Ret(*)(_Visitor, _Variants...);
880 template<
typename... _Args>
881 constexpr decltype(
auto)
882 _M_access(
size_t __first_index, _Args... __rest_indices)
const
884 return _M_arr[__first_index + __do_cookie]
885 ._M_access(__rest_indices...);
888 _Multi_array<_Tp, __rest...> _M_arr[__first + __do_cookie];
918 template<
typename _Array_type,
typename _Index_seq>
919 struct __gen_vtable_impl;
928 template<
typename _Result_type,
typename _Visitor,
size_t... __dimensions,
929 typename... _Variants,
size_t... __indices>
930 struct __gen_vtable_impl<
931 _Multi_array<_Result_type (*)(_Visitor, _Variants...), __dimensions...>,
936 _Variants...>::type>;
938 _Multi_array<_Result_type (*)(_Visitor, _Variants...),
941 static constexpr _Array_type
944 _Array_type __vtable{};
950 template<
size_t... __var_indices>
951 static constexpr void
952 _S_apply_all_alts(_Array_type& __vtable,
955 if constexpr (__extra_visit_slot_needed<_Result_type, _Next>)
956 (_S_apply_single_alt<true, __var_indices>(
957 __vtable._M_arr[__var_indices + 1],
958 &(__vtable._M_arr[0])), ...);
960 (_S_apply_single_alt<false, __var_indices>(
961 __vtable._M_arr[__var_indices]), ...);
964 template<
bool __do_cookie,
size_t __index,
typename _Tp>
965 static constexpr void
966 _S_apply_single_alt(_Tp& __element, _Tp* __cookie_element =
nullptr)
968 if constexpr (__do_cookie)
970 __element = __gen_vtable_impl<
973 *__cookie_element = __gen_vtable_impl<
979 auto __tmp_element = __gen_vtable_impl<
982 static_assert(is_same_v<_Tp,
decltype(__tmp_element)>,
983 "std::visit requires the visitor to have the same "
984 "return type for all alternatives of a variant");
985 __element = __tmp_element;
993 template<
typename _Result_type,
typename _Visitor,
typename... _Variants,
995 struct __gen_vtable_impl<
996 _Multi_array<_Result_type (*)(_Visitor, _Variants...)>,
1000 _Multi_array<_Result_type (*)(_Visitor, _Variants...)>;
1002 template<
size_t __index,
typename _Variant>
1003 static constexpr decltype(
auto)
1004 __element_by_index_or_cookie(_Variant&& __var)
noexcept
1006 if constexpr (__index != variant_npos)
1007 return __variant::__get<__index>(std::forward<_Variant>(__var));
1009 return __variant_cookie{};
1012 static constexpr decltype(
auto)
1013 __visit_invoke(_Visitor&& __visitor, _Variants... __vars)
1015 if constexpr (is_same_v<_Result_type, __variant_idx_cookie>)
1019 __element_by_index_or_cookie<__indices>(
1020 std::forward<_Variants>(__vars))...,
1021 integral_constant<size_t, __indices>()...);
1022 else if constexpr (is_same_v<_Result_type, __variant_cookie>)
1025 __element_by_index_or_cookie<__indices>(
1026 std::forward<_Variants>(__vars))...);
1027 else if constexpr (_Array_type::__result_is_deduced::value)
1030 __element_by_index_or_cookie<__indices>(
1031 std::forward<_Variants>(__vars))...);
1033 return std::__invoke_r<_Result_type>(
1034 std::forward<_Visitor>(__visitor),
1035 __variant::__get<__indices>(std::forward<_Variants>(__vars))...);
1038 static constexpr auto
1041 if constexpr (_Array_type::__result_is_deduced::value)
1043 constexpr bool __visit_ret_type_mismatch =
1044 !is_same_v<
typename _Result_type::type,
1045 decltype(__visit_invoke(std::declval<_Visitor>(),
1046 std::declval<_Variants>()...))>;
1047 if constexpr (__visit_ret_type_mismatch)
1049 struct __cannot_match {};
1050 return __cannot_match{};
1053 return _Array_type{&__visit_invoke};
1056 return _Array_type{&__visit_invoke};
1060 template<
typename _Result_type,
typename _Visitor,
typename... _Variants>
1064 _Multi_array<_Result_type (*)(_Visitor, _Variants...),
1065 variant_size_v<remove_reference_t<_Variants>>...>;
1067 static constexpr _Array_type _S_vtable
1068 = __gen_vtable_impl<_Array_type, std::index_sequence<>>::_S_apply();
1071 template<
size_t _Np,
typename _Tp>
1072 struct _Base_dedup :
public _Tp { };
1074 template<
typename _Variant,
typename __indices>
1075 struct _Variant_hash_base;
1077 template<
typename... _Types,
size_t... __indices>
1078 struct _Variant_hash_base<variant<_Types...>,
1080 : _Base_dedup<__indices, __poison_hash<remove_const_t<_Types>>>... { };
1083 template<
size_t _Np,
typename _Variant,
1084 typename _AsV =
decltype(__variant::__as(std::declval<_Variant>())),
1085 typename _Tp = variant_alternative_t<_Np, remove_reference_t<_AsV>>>
1087 = __conditional_t<is_lvalue_reference_v<_Variant>, _Tp&, _Tp&&>;
1090 template<
typename _Visitor,
typename... _Variants>
1091 using __visit_result_t
1092 = invoke_result_t<_Visitor, __get_t<0, _Variants>...>;
1094 template<
typename _Tp,
typename... _Types>
1095 constexpr inline bool __same_types = (is_same_v<_Tp, _Types> && ...);
1097 template <
typename _Visitor,
typename _Variant,
size_t... _Idxs>
1100 return __same_types<
1101 invoke_result_t<_Visitor, __get_t<_Idxs, _Variant>>...
1108 template<
typename _Tp,
typename... _Types>
1110 holds_alternative(
const variant<_Types...>& __v)
noexcept
1112 static_assert(__detail::__variant::__exactly_once<_Tp, _Types...>,
1113 "T must occur exactly once in alternatives");
1114 return __v.index() == std::__find_uniq_type_in_pack<_Tp, _Types...>();
1117 template<
typename _Tp,
typename... _Types>
1119 get(variant<_Types...>& __v)
1121 static_assert(__detail::__variant::__exactly_once<_Tp, _Types...>,
1122 "T must occur exactly once in alternatives");
1123 static_assert(!is_void_v<_Tp>,
"_Tp must not be void");
1124 constexpr size_t __n = std::__find_uniq_type_in_pack<_Tp, _Types...>();
1125 return std::get<__n>(__v);
1128 template<
typename _Tp,
typename... _Types>
1130 get(variant<_Types...>&& __v)
1132 static_assert(__detail::__variant::__exactly_once<_Tp, _Types...>,
1133 "T must occur exactly once in alternatives");
1134 static_assert(!is_void_v<_Tp>,
"_Tp must not be void");
1135 constexpr size_t __n = std::__find_uniq_type_in_pack<_Tp, _Types...>();
1139 template<
typename _Tp,
typename... _Types>
1140 constexpr const _Tp&
1141 get(
const variant<_Types...>& __v)
1143 static_assert(__detail::__variant::__exactly_once<_Tp, _Types...>,
1144 "T must occur exactly once in alternatives");
1145 static_assert(!is_void_v<_Tp>,
"_Tp must not be void");
1146 constexpr size_t __n = std::__find_uniq_type_in_pack<_Tp, _Types...>();
1147 return std::get<__n>(__v);
1150 template<
typename _Tp,
typename... _Types>
1151 constexpr const _Tp&&
1152 get(
const variant<_Types...>&& __v)
1154 static_assert(__detail::__variant::__exactly_once<_Tp, _Types...>,
1155 "T must occur exactly once in alternatives");
1156 static_assert(!is_void_v<_Tp>,
"_Tp must not be void");
1157 constexpr size_t __n = std::__find_uniq_type_in_pack<_Tp, _Types...>();
1161 template<
size_t _Np,
typename... _Types>
1162 constexpr add_pointer_t<variant_alternative_t<_Np, variant<_Types...>>>
1163 get_if(variant<_Types...>* __ptr)
noexcept
1165 using _Alternative_type = variant_alternative_t<_Np, variant<_Types...>>;
1166 static_assert(_Np <
sizeof...(_Types),
1167 "The index must be in [0, number of alternatives)");
1168 static_assert(!is_void_v<_Alternative_type>,
"_Tp must not be void");
1169 if (__ptr && __ptr->index() == _Np)
1174 template<
size_t _Np,
typename... _Types>
1176 add_pointer_t<
const variant_alternative_t<_Np, variant<_Types...>>>
1177 get_if(
const variant<_Types...>* __ptr)
noexcept
1179 using _Alternative_type = variant_alternative_t<_Np, variant<_Types...>>;
1180 static_assert(_Np <
sizeof...(_Types),
1181 "The index must be in [0, number of alternatives)");
1182 static_assert(!is_void_v<_Alternative_type>,
"_Tp must not be void");
1183 if (__ptr && __ptr->index() == _Np)
1188 template<
typename _Tp,
typename... _Types>
1189 constexpr add_pointer_t<_Tp>
1190 get_if(variant<_Types...>* __ptr)
noexcept
1192 static_assert(__detail::__variant::__exactly_once<_Tp, _Types...>,
1193 "T must occur exactly once in alternatives");
1194 static_assert(!is_void_v<_Tp>,
"_Tp must not be void");
1195 constexpr size_t __n = std::__find_uniq_type_in_pack<_Tp, _Types...>();
1196 return std::get_if<__n>(__ptr);
1199 template<
typename _Tp,
typename... _Types>
1200 constexpr add_pointer_t<const _Tp>
1201 get_if(
const variant<_Types...>* __ptr)
noexcept
1203 static_assert(__detail::__variant::__exactly_once<_Tp, _Types...>,
1204 "T must occur exactly once in alternatives");
1205 static_assert(!is_void_v<_Tp>,
"_Tp must not be void");
1206 constexpr size_t __n = std::__find_uniq_type_in_pack<_Tp, _Types...>();
1207 return std::get_if<__n>(__ptr);
1210 struct monostate { };
1212#define _VARIANT_RELATION_FUNCTION_TEMPLATE(__OP, __NAME) \
1213 template<typename... _Types> \
1214 constexpr bool operator __OP(const variant<_Types...>& __lhs, \
1215 const variant<_Types...>& __rhs) \
1217 bool __ret = true; \
1218 __detail::__variant::__raw_idx_visit( \
1219 [&__ret, &__lhs] (auto&& __rhs_mem, auto __rhs_index) mutable \
1221 if constexpr (__rhs_index != variant_npos) \
1223 if (__lhs.index() == __rhs_index) \
1225 auto& __this_mem = std::get<__rhs_index>(__lhs); \
1226 __ret = __this_mem __OP __rhs_mem; \
1229 __ret = (__lhs.index() + 1) __OP (__rhs_index + 1); \
1232 __ret = (__lhs.index() + 1) __OP (__rhs_index + 1); \
1237 _VARIANT_RELATION_FUNCTION_TEMPLATE(<, less)
1238 _VARIANT_RELATION_FUNCTION_TEMPLATE(<=, less_equal)
1239 _VARIANT_RELATION_FUNCTION_TEMPLATE(==, equal)
1240 _VARIANT_RELATION_FUNCTION_TEMPLATE(!=, not_equal)
1241 _VARIANT_RELATION_FUNCTION_TEMPLATE(>=, greater_equal)
1242 _VARIANT_RELATION_FUNCTION_TEMPLATE(>, greater)
1244#undef _VARIANT_RELATION_FUNCTION_TEMPLATE
1246 constexpr bool operator==(monostate, monostate)
noexcept {
return true; }
1248#ifdef __cpp_lib_three_way_comparison
1249 template<
typename... _Types>
1250 requires (three_way_comparable<_Types> && ...)
1252 common_comparison_category_t<compare_three_way_result_t<_Types>...>
1253 operator<=>(
const variant<_Types...>& __v,
const variant<_Types...>& __w)
1255 common_comparison_category_t<compare_three_way_result_t<_Types>...> __ret
1256 = strong_ordering::equal;
1258 __detail::__variant::__raw_idx_visit(
1259 [&__ret, &__v] (
auto&& __w_mem,
auto __w_index)
mutable
1261 if constexpr (__w_index != variant_npos)
1263 if (__v.index() == __w_index)
1265 auto& __this_mem = std::get<__w_index>(__v);
1266 __ret = __this_mem <=> __w_mem;
1270 __ret = (__v.index() + 1) <=> (__w_index + 1);
1275 constexpr strong_ordering
1276 operator<=>(monostate, monostate)
noexcept {
return strong_ordering::equal; }
1278 constexpr bool operator!=(monostate, monostate)
noexcept {
return false; }
1279 constexpr bool operator<(monostate, monostate)
noexcept {
return false; }
1280 constexpr bool operator>(monostate, monostate)
noexcept {
return false; }
1281 constexpr bool operator<=(monostate, monostate)
noexcept {
return true; }
1282 constexpr bool operator>=(monostate, monostate)
noexcept {
return true; }
1285 template<
typename _Visitor,
typename... _Variants>
1286 constexpr __detail::__variant::__visit_result_t<_Visitor, _Variants...>
1287 visit(_Visitor&&, _Variants&&...);
1289 template<
typename... _Types>
1290 _GLIBCXX20_CONSTEXPR
1291 inline enable_if_t<(is_move_constructible_v<_Types> && ...)
1292 && (is_swappable_v<_Types> && ...)>
1293 swap(variant<_Types...>& __lhs, variant<_Types...>& __rhs)
1294 noexcept(
noexcept(__lhs.swap(__rhs)))
1295 { __lhs.swap(__rhs); }
1297 template<
typename... _Types>
1298 enable_if_t<!((is_move_constructible_v<_Types> && ...)
1299 && (is_swappable_v<_Types> && ...))>
1300 swap(variant<_Types...>&, variant<_Types...>&) =
delete;
1302 class bad_variant_access :
public exception
1305 bad_variant_access() noexcept { }
1307 const char* what() const noexcept
override
1308 {
return _M_reason; }
1311 bad_variant_access(
const char* __reason) noexcept : _M_reason(__reason) { }
1314 const char* _M_reason =
"bad variant access";
1316 friend void __throw_bad_variant_access(
const char* __what);
1321 __throw_bad_variant_access(
const char* __what)
1322 { _GLIBCXX_THROW_OR_ABORT(bad_variant_access(__what)); }
1325 __throw_bad_variant_access(
bool __valueless)
1327 if (__valueless) [[__unlikely__]]
1328 __throw_bad_variant_access(
"std::get: variant is valueless");
1330 __throw_bad_variant_access(
"std::get: wrong index for variant");
1333 template<
typename... _Types>
1335 :
private __detail::__variant::_Variant_base<_Types...>,
1336 private _Enable_default_constructor<
1337 __detail::__variant::_Traits<_Types...>::_S_default_ctor,
1338 variant<_Types...>>,
1339 private _Enable_copy_move<
1340 __detail::__variant::_Traits<_Types...>::_S_copy_ctor,
1341 __detail::__variant::_Traits<_Types...>::_S_copy_assign,
1342 __detail::__variant::_Traits<_Types...>::_S_move_ctor,
1343 __detail::__variant::_Traits<_Types...>::_S_move_assign,
1347 template <
typename... _UTypes,
typename _Tp>
1348 friend _GLIBCXX20_CONSTEXPR
decltype(
auto)
1349 __variant_cast(_Tp&&);
1351 static_assert(
sizeof...(_Types) > 0,
1352 "variant must have at least one alternative");
1353 static_assert(!(std::is_reference_v<_Types> || ...),
1354 "variant must have no reference alternative");
1355 static_assert(!(std::is_void_v<_Types> || ...),
1356 "variant must have no void alternative");
1358 using _Base = __detail::__variant::_Variant_base<_Types...>;
1359 using _Default_ctor_enabler =
1360 _Enable_default_constructor<
1361 __detail::__variant::_Traits<_Types...>::_S_default_ctor,
1362 variant<_Types...>>;
1364 template<
typename _Tp>
1365 static constexpr bool __not_self
1366 = !is_same_v<__remove_cvref_t<_Tp>, variant>;
1368 template<
typename _Tp>
1369 static constexpr bool
1370 __exactly_once = __detail::__variant::__exactly_once<_Tp, _Types...>;
1372 template<
typename _Tp>
1373 static constexpr size_t __accepted_index
1374 = __detail::__variant::__accepted_index<_Tp, variant>;
1376 template<
size_t _Np,
typename =
enable_if_t<(_Np <
sizeof...(_Types))>>
1377 using __to_type =
typename _Nth_type<_Np, _Types...>::type;
1379 template<
typename _Tp,
typename = enable_if_t<__not_self<_Tp>>>
1380 using __accepted_type = __to_type<__accepted_index<_Tp>>;
1382 template<
typename _Tp>
1383 static constexpr size_t __index_of
1384 = std::__find_uniq_type_in_pack<_Tp, _Types...>();
1386 using _Traits = __detail::__variant::_Traits<_Types...>;
1388 template<
typename _Tp>
1390 template<
typename _Tp>
1391 struct __is_in_place_tag<in_place_type_t<_Tp>> :
true_type { };
1392 template<
size_t _Np>
1393 struct __is_in_place_tag<in_place_index_t<_Np>> :
true_type { };
1395 template<
typename _Tp>
1396 static constexpr bool __not_in_place_tag
1397 = !__is_in_place_tag<__remove_cvref_t<_Tp>>::value;
1400 variant() =
default;
1401 variant(
const variant& __rhs) =
default;
1402 variant(variant&&) =
default;
1403 variant& operator=(
const variant&) =
default;
1404 variant& operator=(variant&&) =
default;
1405 _GLIBCXX20_CONSTEXPR ~variant() =
default;
1407 template<
typename _Tp,
1410 typename _Tj = __accepted_type<_Tp&&>,
1412 && is_constructible_v<_Tj, _Tp>>>
1415 noexcept(is_nothrow_constructible_v<_Tj, _Tp>)
1416 : variant(in_place_index<__accepted_index<_Tp>>,
1417 std::forward<_Tp>(__t))
1420 template<
typename _Tp,
typename... _Args,
1421 typename = enable_if_t<__exactly_once<_Tp>
1422 && is_constructible_v<_Tp, _Args...>>>
1424 variant(in_place_type_t<_Tp>, _Args&&... __args)
1425 : variant(in_place_index<__index_of<_Tp>>,
1429 template<
typename _Tp,
typename _Up,
typename... _Args,
1430 typename = enable_if_t<__exactly_once<_Tp>
1431 && is_constructible_v<_Tp,
1432 initializer_list<_Up>&, _Args...>>>
1434 variant(in_place_type_t<_Tp>, initializer_list<_Up> __il,
1436 : variant(in_place_index<__index_of<_Tp>>, __il,
1440 template<
size_t _Np,
typename... _Args,
1441 typename _Tp = __to_type<_Np>,
1442 typename =
enable_if_t<is_constructible_v<_Tp, _Args...>>>
1444 variant(in_place_index_t<_Np>, _Args&&... __args)
1445 : _Base(in_place_index<_Np>,
std::
forward<_Args>(__args)...),
1446 _Default_ctor_enabler(_Enable_default_constructor_tag{})
1449 template<
size_t _Np,
typename _Up,
typename... _Args,
1450 typename _Tp = __to_type<_Np>,
1452 initializer_list<_Up>&,
1455 variant(in_place_index_t<_Np>, initializer_list<_Up> __il,
1457 : _Base(in_place_index<_Np>, __il,
std::
forward<_Args>(__args)...),
1458 _Default_ctor_enabler(_Enable_default_constructor_tag{})
1461 template<
typename _Tp>
1462 _GLIBCXX20_CONSTEXPR
1463 enable_if_t<__exactly_once<__accepted_type<_Tp&&>>
1464 && is_constructible_v<__accepted_type<_Tp&&>, _Tp>
1465 && is_assignable_v<__accepted_type<_Tp&&>&, _Tp>,
1467 operator=(_Tp&& __rhs)
1468 noexcept(is_nothrow_assignable_v<__accepted_type<_Tp&&>&, _Tp>
1469 && is_nothrow_constructible_v<__accepted_type<_Tp&&>, _Tp>)
1471 constexpr auto __index = __accepted_index<_Tp>;
1472 if (index() == __index)
1473 std::get<__index>(*
this) = std::forward<_Tp>(__rhs);
1476 using _Tj = __accepted_type<_Tp&&>;
1477 if constexpr (is_nothrow_constructible_v<_Tj, _Tp>
1478 || !is_nothrow_move_constructible_v<_Tj>)
1479 this->emplace<__index>(std::forward<_Tp>(__rhs));
1481 operator=(variant(std::forward<_Tp>(__rhs)));
1486 template<
typename _Tp,
typename... _Args>
1487 _GLIBCXX20_CONSTEXPR
1488 enable_if_t<is_constructible_v<_Tp, _Args...> && __exactly_once<_Tp>,
1490 emplace(_Args&&... __args)
1492 constexpr size_t __index = __index_of<_Tp>;
1493 return this->emplace<__index>(std::forward<_Args>(__args)...);
1496 template<
typename _Tp,
typename _Up,
typename... _Args>
1497 _GLIBCXX20_CONSTEXPR
1498 enable_if_t<is_constructible_v<_Tp, initializer_list<_Up>&, _Args...>
1499 && __exactly_once<_Tp>,
1501 emplace(initializer_list<_Up> __il, _Args&&... __args)
1503 constexpr size_t __index = __index_of<_Tp>;
1504 return this->emplace<__index>(__il, std::forward<_Args>(__args)...);
1507 template<
size_t _Np,
typename... _Args>
1508 _GLIBCXX20_CONSTEXPR
1509 enable_if_t<is_constructible_v<__to_type<_Np>, _Args...>,
1511 emplace(_Args&&... __args)
1513 namespace __variant = std::__detail::__variant;
1514 using type =
typename _Nth_type<_Np, _Types...>::type;
1517 if constexpr (is_nothrow_constructible_v<type, _Args...>)
1519 __variant::__emplace<_Np>(*
this, std::forward<_Args>(__args)...);
1521 else if constexpr (is_scalar_v<type>)
1524 const type __tmp(std::forward<_Args>(__args)...);
1526 __variant::__emplace<_Np>(*
this, __tmp);
1528 else if constexpr (__variant::_Never_valueless_alt<type>()
1529 && _Traits::_S_move_assign)
1532 variant __tmp(in_place_index<_Np>,
1533 std::forward<_Args>(__args)...);
1541 __variant::__emplace<_Np>(*
this, std::forward<_Args>(__args)...);
1543 return std::get<_Np>(*
this);
1546 template<
size_t _Np,
typename _Up,
typename... _Args>
1547 _GLIBCXX20_CONSTEXPR
1548 enable_if_t<is_constructible_v<__to_type<_Np>,
1549 initializer_list<_Up>&, _Args...>,
1551 emplace(initializer_list<_Up> __il, _Args&&... __args)
1553 namespace __variant = std::__detail::__variant;
1554 using type =
typename _Nth_type<_Np, _Types...>::type;
1557 if constexpr (is_nothrow_constructible_v<type,
1558 initializer_list<_Up>&,
1561 __variant::__emplace<_Np>(*
this, __il,
1562 std::forward<_Args>(__args)...);
1564 else if constexpr (__variant::_Never_valueless_alt<type>()
1565 && _Traits::_S_move_assign)
1568 variant __tmp(in_place_index<_Np>, __il,
1569 std::forward<_Args>(__args)...);
1577 __variant::__emplace<_Np>(*
this, __il,
1578 std::forward<_Args>(__args)...);
1580 return std::get<_Np>(*
this);
1583 template<
size_t _Np,
typename... _Args>
1584 enable_if_t<!(_Np <
sizeof...(_Types))> emplace(_Args&&...) =
delete;
1586 template<
typename _Tp,
typename... _Args>
1587 enable_if_t<!__exactly_once<_Tp>> emplace(_Args&&...) =
delete;
1589 constexpr bool valueless_by_exception() const noexcept
1590 {
return !this->_M_valid(); }
1592 constexpr size_t index() const noexcept
1594 using __index_type =
typename _Base::__index_type;
1595 if constexpr (__detail::__variant::__never_valueless<_Types...>())
1596 return this->_M_index;
1597 else if constexpr (
sizeof...(_Types) <= __index_type(-1) / 2)
1598 return make_signed_t<__index_type>(this->_M_index);
1600 return size_t(__index_type(this->_M_index + 1)) - 1;
1603 _GLIBCXX20_CONSTEXPR
1605 swap(variant& __rhs)
1606 noexcept((__is_nothrow_swappable<_Types>::value && ...)
1607 && is_nothrow_move_constructible_v<variant>)
1609 static_assert((is_move_constructible_v<_Types> && ...));
1612 if (__rhs.valueless_by_exception()) [[__unlikely__]]
1614 if (!this->valueless_by_exception()) [[__likely__]]
1619 namespace __variant = __detail::__variant;
1621 __variant::__raw_idx_visit(
1622 [
this, &__rhs](
auto&& __rhs_mem,
auto __rhs_index)
mutable
1624 constexpr size_t __j = __rhs_index;
1625 if constexpr (__j != variant_npos)
1627 if (this->index() == __j)
1630 swap(std::get<__j>(*
this), __rhs_mem);
1636 if constexpr (_Traits::_S_trivial_move_assign)
1639 __variant::__raw_idx_visit(
1640 [&__rhs](
auto&& __this_mem,
auto __this_index)
mutable
1642 constexpr size_t __k = __this_index;
1643 if constexpr (__k != variant_npos)
1644 __variant::__emplace<__k>(__rhs,
1648 __variant::__emplace<__j>(*
this,
std::move(__tmp));
1654#if defined(__clang__) && __clang_major__ <= 7
1660 template<
size_t _Np,
typename _Vp>
1661 friend constexpr decltype(
auto)
1662 __detail::__variant::__get(_Vp&& __v)
noexcept;
1664#define _VARIANT_RELATION_FUNCTION_TEMPLATE(__OP) \
1665 template<typename... _Tp> \
1666 friend constexpr bool \
1667 operator __OP(const variant<_Tp...>& __lhs, \
1668 const variant<_Tp...>& __rhs);
1670 _VARIANT_RELATION_FUNCTION_TEMPLATE(<)
1671 _VARIANT_RELATION_FUNCTION_TEMPLATE(<=)
1672 _VARIANT_RELATION_FUNCTION_TEMPLATE(==)
1673 _VARIANT_RELATION_FUNCTION_TEMPLATE(!=)
1674 _VARIANT_RELATION_FUNCTION_TEMPLATE(>=)
1675 _VARIANT_RELATION_FUNCTION_TEMPLATE(>)
1677#undef _VARIANT_RELATION_FUNCTION_TEMPLATE
1680 template<
size_t _Np,
typename... _Types>
1681 constexpr variant_alternative_t<_Np, variant<_Types...>>&
1682 get(variant<_Types...>& __v)
1684 static_assert(_Np <
sizeof...(_Types),
1685 "The index must be in [0, number of alternatives)");
1686 if (__v.index() != _Np)
1687 __throw_bad_variant_access(__v.valueless_by_exception());
1688 return __detail::__variant::__get<_Np>(__v);
1691 template<
size_t _Np,
typename... _Types>
1692 constexpr variant_alternative_t<_Np, variant<_Types...>>&&
1693 get(variant<_Types...>&& __v)
1695 static_assert(_Np <
sizeof...(_Types),
1696 "The index must be in [0, number of alternatives)");
1697 if (__v.index() != _Np)
1698 __throw_bad_variant_access(__v.valueless_by_exception());
1699 return __detail::__variant::__get<_Np>(
std::move(__v));
1702 template<
size_t _Np,
typename... _Types>
1703 constexpr const variant_alternative_t<_Np, variant<_Types...>>&
1704 get(
const variant<_Types...>& __v)
1706 static_assert(_Np <
sizeof...(_Types),
1707 "The index must be in [0, number of alternatives)");
1708 if (__v.index() != _Np)
1709 __throw_bad_variant_access(__v.valueless_by_exception());
1710 return __detail::__variant::__get<_Np>(__v);
1713 template<
size_t _Np,
typename... _Types>
1714 constexpr const variant_alternative_t<_Np, variant<_Types...>>&&
1715 get(
const variant<_Types...>&& __v)
1717 static_assert(_Np <
sizeof...(_Types),
1718 "The index must be in [0, number of alternatives)");
1719 if (__v.index() != _Np)
1720 __throw_bad_variant_access(__v.valueless_by_exception());
1721 return __detail::__variant::__get<_Np>(
std::move(__v));
1725 template<
typename _Result_type,
typename _Visitor,
typename... _Variants>
1726 constexpr decltype(
auto)
1727 __do_visit(_Visitor&& __visitor, _Variants&&... __variants)
1730 if constexpr (
sizeof...(_Variants) == 0)
1732 if constexpr (is_void_v<_Result_type>)
1733 return (
void) std::forward<_Visitor>(__visitor)();
1735 return std::forward<_Visitor>(__visitor)();
1739 constexpr size_t __max = 11;
1742 using _V0 =
typename _Nth_type<0, _Variants...>::type;
1744 constexpr auto __n = variant_size_v<remove_reference_t<_V0>>;
1746 if constexpr (
sizeof...(_Variants) > 1 || __n > __max)
1749 constexpr auto& __vtable = __detail::__variant::__gen_vtable<
1750 _Result_type, _Visitor&&, _Variants&&...>::_S_vtable;
1752 auto __func_ptr = __vtable._M_access(__variants.index()...);
1753 return (*__func_ptr)(std::forward<_Visitor>(__visitor),
1754 std::forward<_Variants>(__variants)...);
1760 = [](_V0& __v, ...) -> _V0& {
return __v; }(__variants...);
1762 using __detail::__variant::_Multi_array;
1763 using __detail::__variant::__gen_vtable_impl;
1764 using _Ma = _Multi_array<_Result_type (*)(_Visitor&&, _V0&&)>;
1766#ifdef _GLIBCXX_DEBUG
1767# define _GLIBCXX_VISIT_UNREACHABLE __builtin_trap
1769# define _GLIBCXX_VISIT_UNREACHABLE __builtin_unreachable
1772#define _GLIBCXX_VISIT_CASE(N) \
1775 if constexpr (N < __n) \
1777 return __gen_vtable_impl<_Ma, index_sequence<N>>:: \
1778 __visit_invoke(std::forward<_Visitor>(__visitor), \
1779 std::forward<_V0>(__v0)); \
1781 else _GLIBCXX_VISIT_UNREACHABLE(); \
1784 switch (__v0.index())
1786 _GLIBCXX_VISIT_CASE(0)
1787 _GLIBCXX_VISIT_CASE(1)
1788 _GLIBCXX_VISIT_CASE(2)
1789 _GLIBCXX_VISIT_CASE(3)
1790 _GLIBCXX_VISIT_CASE(4)
1791 _GLIBCXX_VISIT_CASE(5)
1792 _GLIBCXX_VISIT_CASE(6)
1793 _GLIBCXX_VISIT_CASE(7)
1794 _GLIBCXX_VISIT_CASE(8)
1795 _GLIBCXX_VISIT_CASE(9)
1796 _GLIBCXX_VISIT_CASE(10)
1798 using __detail::__variant::__variant_idx_cookie;
1799 using __detail::__variant::__variant_cookie;
1800 if constexpr (is_same_v<_Result_type, __variant_idx_cookie>
1801 || is_same_v<_Result_type, __variant_cookie>)
1803 using _Npos = index_sequence<variant_npos>;
1804 return __gen_vtable_impl<_Ma, _Npos>::
1805 __visit_invoke(std::forward<_Visitor>(__visitor),
1806 std::forward<_V0>(__v0));
1809 _GLIBCXX_VISIT_UNREACHABLE();
1811 _GLIBCXX_VISIT_UNREACHABLE();
1813#undef _GLIBCXX_VISIT_CASE
1814#undef _GLIBCXX_VISIT_UNREACHABLE
1820 template<
typename _Visitor,
typename... _Variants>
1821 constexpr __detail::__variant::__visit_result_t<_Visitor, _Variants...>
1822 visit(_Visitor&& __visitor, _Variants&&... __variants)
1824 namespace __variant = std::__detail::__variant;
1826 if ((__variant::__as(__variants).valueless_by_exception() || ...))
1827 __throw_bad_variant_access(
"std::visit: variant is valueless");
1830 = __detail::__variant::__visit_result_t<_Visitor, _Variants...>;
1832 using _Tag = __detail::__variant::__deduce_visit_result<_Result_type>;
1834 if constexpr (
sizeof...(_Variants) == 1)
1836 using _Vp =
decltype(__variant::__as(std::declval<_Variants>()...));
1838 constexpr bool __visit_rettypes_match = __detail::__variant::
1839 __check_visitor_results<_Visitor, _Vp>(
1841 if constexpr (!__visit_rettypes_match)
1843 static_assert(__visit_rettypes_match,
1844 "std::visit requires the visitor to have the same "
1845 "return type for all alternatives of a variant");
1849 return std::__do_visit<_Tag>(
1850 std::forward<_Visitor>(__visitor),
1851 static_cast<_Vp
>(__variants)...);
1854 return std::__do_visit<_Tag>(
1855 std::forward<_Visitor>(__visitor),
1856 __variant::__as(std::forward<_Variants>(__variants))...);
1859#if __cplusplus > 201703L
1860 template<
typename _Res,
typename _Visitor,
typename... _Variants>
1862 visit(_Visitor&& __visitor, _Variants&&... __variants)
1864 namespace __variant = std::__detail::__variant;
1866 if ((__variant::__as(__variants).valueless_by_exception() || ...))
1867 __throw_bad_variant_access(
"std::visit<R>: variant is valueless");
1869 return std::__do_visit<_Res>(std::forward<_Visitor>(__visitor),
1870 __variant::__as(std::forward<_Variants>(__variants))...);
1875 template<bool,
typename... _Types>
1876 struct __variant_hash_call_base_impl
1879 operator()(
const variant<_Types...>& __t)
const
1880 noexcept((is_nothrow_invocable_v<hash<decay_t<_Types>>, _Types> && ...))
1883 __detail::__variant::__raw_visit(
1884 [&__t, &__ret](
auto&& __t_mem)
mutable
1886 using _Type = __remove_cvref_t<
decltype(__t_mem)>;
1887 if constexpr (!is_same_v<_Type,
1888 __detail::__variant::__variant_cookie>)
1898 template<
typename... _Types>
1899 struct __variant_hash_call_base_impl<false, _Types...> {};
1901 template<
typename... _Types>
1902 using __variant_hash_call_base =
1903 __variant_hash_call_base_impl<(__poison_hash<remove_const_t<_Types>>::
1904 __enable_hash_call &&...), _Types...>;
1907 template<
typename... _Types>
1908 struct hash<variant<_Types...>>
1909 :
private __detail::__variant::_Variant_hash_base<
1910 variant<_Types...>, std::index_sequence_for<_Types...>>,
1911 public __variant_hash_call_base<_Types...>
1913 using result_type [[__deprecated__]] = size_t;
1914 using argument_type [[__deprecated__]] = variant<_Types...>;
1918 struct hash<monostate>
1920 using result_type [[__deprecated__]] = size_t;
1921 using argument_type [[__deprecated__]] = monostate;
1924 operator()(
const monostate&)
const noexcept
1926 constexpr size_t __magic_monostate_hash = -7777;
1927 return __magic_monostate_hash;
1931 template<
typename... _Types>
1932 struct __is_fast_hash<hash<variant<_Types...>>>
1936_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.
Class template integer_sequence.