29#ifndef _GLIBCXX_VARIANT
30#define _GLIBCXX_VARIANT 1
32#pragma GCC system_header
34#define __glibcxx_want_freestanding_variant
35#define __glibcxx_want_variant
38#ifdef __cpp_lib_variant
49#if __cplusplus >= 202002L
54#if __cpp_lib_variant < 202106L
59namespace std _GLIBCXX_VISIBILITY(default)
61_GLIBCXX_BEGIN_NAMESPACE_VERSION
63 template<
typename... _Types>
class tuple;
64 template<
typename... _Types>
class variant;
65 template <
typename>
struct hash;
67 template<
typename _Variant>
70 template<
typename _Variant>
71 struct variant_size<const _Variant> : variant_size<_Variant> {};
73 template<
typename _Variant>
74 struct variant_size<volatile _Variant> : variant_size<_Variant> {};
76 template<
typename _Variant>
77 struct variant_size<const volatile _Variant> : variant_size<_Variant> {};
79 template<
typename... _Types>
80 struct variant_size<variant<_Types...>>
83 template<
typename _Variant>
84 inline constexpr size_t variant_size_v = variant_size<_Variant>::value;
86 template<
typename... _Types>
87 inline constexpr size_t
88 variant_size_v<variant<_Types...>> =
sizeof...(_Types);
90 template<
typename... _Types>
91 inline constexpr size_t
92 variant_size_v<
const variant<_Types...>> =
sizeof...(_Types);
94 template<
size_t _Np,
typename _Variant>
95 struct variant_alternative;
97 template<
size_t _Np,
typename... _Types>
98 struct variant_alternative<_Np, variant<_Types...>>
100 static_assert(_Np <
sizeof...(_Types));
102 using type =
typename _Nth_type<_Np, _Types...>::type;
105 template<
size_t _Np,
typename _Variant>
106 using variant_alternative_t =
107 typename variant_alternative<_Np, _Variant>::type;
109 template<
size_t _Np,
typename _Variant>
110 struct variant_alternative<_Np, const _Variant>
111 {
using type =
const variant_alternative_t<_Np, _Variant>; };
113 template<
size_t _Np,
typename _Variant>
114 struct variant_alternative<_Np, volatile _Variant>
115 {
using type =
volatile variant_alternative_t<_Np, _Variant>; };
117 template<
size_t _Np,
typename _Variant>
118 struct variant_alternative<_Np, const volatile _Variant>
119 {
using type =
const volatile variant_alternative_t<_Np, _Variant>; };
121 inline constexpr size_t variant_npos = -1;
123 template<
size_t _Np,
typename... _Types>
124 constexpr variant_alternative_t<_Np, variant<_Types...>>&
125 get(variant<_Types...>&);
127 template<
size_t _Np,
typename... _Types>
128 constexpr variant_alternative_t<_Np, variant<_Types...>>&&
129 get(variant<_Types...>&&);
131 template<
size_t _Np,
typename... _Types>
132 constexpr variant_alternative_t<_Np, variant<_Types...>>
const&
133 get(
const variant<_Types...>&);
135 template<
size_t _Np,
typename... _Types>
136 constexpr variant_alternative_t<_Np, variant<_Types...>>
const&&
137 get(
const variant<_Types...>&&);
139 template<
typename _Result_type,
typename _Visitor,
typename... _Variants>
140 constexpr decltype(
auto)
141 __do_visit(_Visitor&& __visitor, _Variants&&... __variants);
143 template <
typename... _Types,
typename _Tp>
146 __variant_cast(_Tp&& __rhs)
148 if constexpr (is_lvalue_reference_v<_Tp>)
150 if constexpr (is_const_v<remove_reference_t<_Tp>>)
151 return static_cast<const variant<_Types...
>&>(__rhs);
153 return static_cast<variant<_Types...
>&>(__rhs);
156 return static_cast<variant<_Types...
>&&>(__rhs);
164 struct __variant_cookie {};
166 struct __variant_idx_cookie {
using type = __variant_idx_cookie; };
168 template<
typename _Tp>
struct __deduce_visit_result {
using type = _Tp; };
171 template<
typename _Visitor,
typename... _Variants>
173 __raw_visit(_Visitor&& __visitor, _Variants&&... __variants)
175 std::__do_visit<__variant_cookie>(std::forward<_Visitor>(__visitor),
176 std::forward<_Variants>(__variants)...);
180 template<
typename _Visitor,
typename... _Variants>
182 __raw_idx_visit(_Visitor&& __visitor, _Variants&&... __variants)
184 std::__do_visit<__variant_idx_cookie>(std::forward<_Visitor>(__visitor),
185 std::forward<_Variants>(__variants)...);
190 template<
typename... _Types>
191 constexpr std::variant<_Types...>&
192 __as(std::variant<_Types...>& __v)
noexcept
195 template<
typename... _Types>
196 constexpr const std::variant<_Types...>&
197 __as(
const std::variant<_Types...>& __v)
noexcept
200 template<
typename... _Types>
201 constexpr std::variant<_Types...>&&
202 __as(std::variant<_Types...>&& __v)
noexcept
205 template<
typename... _Types>
206 constexpr const std::variant<_Types...>&&
207 __as(
const std::variant<_Types...>&& __v)
noexcept
216 template<
typename _Type,
bool = std::is_trivially_destructible_v<_Type>>
217 struct _Uninitialized;
219 template<
typename _Type>
220 struct _Uninitialized<_Type, true>
222 template<
typename... _Args>
224 _Uninitialized(in_place_index_t<0>, _Args&&... __args)
228 constexpr const _Type& _M_get() const & noexcept
229 {
return _M_storage; }
231 constexpr _Type& _M_get() &
noexcept
232 {
return _M_storage; }
234 constexpr const _Type&& _M_get() const && noexcept
237 constexpr _Type&& _M_get() &&
noexcept
243 template<
typename _Type>
244 struct _Uninitialized<_Type, false>
246#if __cpp_lib_variant >= 202106L
247 template<
typename... _Args>
249 _Uninitialized(in_place_index_t<0>, _Args&&... __args)
253 constexpr ~_Uninitialized() { }
255 _Uninitialized(
const _Uninitialized&) =
default;
256 _Uninitialized(_Uninitialized&&) =
default;
257 _Uninitialized& operator=(
const _Uninitialized&) =
default;
258 _Uninitialized& operator=(_Uninitialized&&) =
default;
260 constexpr const _Type& _M_get() const & noexcept
261 {
return _M_storage; }
263 constexpr _Type& _M_get() &
noexcept
264 {
return _M_storage; }
266 constexpr const _Type&& _M_get() const && noexcept
269 constexpr _Type&& _M_get() &&
noexcept
272 struct _Empty_byte { };
275 _Empty_byte _M_empty;
279 template<
typename... _Args>
281 _Uninitialized(in_place_index_t<0>, _Args&&... __args)
284 _Type(std::forward<_Args>(__args)...);
287 const _Type& _M_get() const & noexcept
288 {
return *_M_storage._M_ptr(); }
290 _Type& _M_get() &
noexcept
291 {
return *_M_storage._M_ptr(); }
293 const _Type&& _M_get() const && noexcept
294 {
return std::move(*_M_storage._M_ptr()); }
296 _Type&& _M_get() &&
noexcept
297 {
return std::move(*_M_storage._M_ptr()); }
299 __gnu_cxx::__aligned_membuf<_Type> _M_storage;
303 template<
size_t _Np,
typename _Union>
304 constexpr decltype(
auto)
305 __get_n(_Union&& __u)
noexcept
307 if constexpr (_Np == 0)
308 return std::forward<_Union>(__u)._M_first._M_get();
309 else if constexpr (_Np == 1)
310 return std::forward<_Union>(__u)._M_rest._M_first._M_get();
311 else if constexpr (_Np == 2)
312 return std::forward<_Union>(__u)._M_rest._M_rest._M_first._M_get();
314 return __variant::__get_n<_Np - 3>(
315 std::forward<_Union>(__u)._M_rest._M_rest._M_rest);
319 template<
size_t _Np,
typename _Variant>
320 constexpr decltype(
auto)
321 __get(_Variant&& __v)
noexcept
322 {
return __variant::__get_n<_Np>(std::forward<_Variant>(__v)._M_u); }
325 template<
size_t _Np,
typename _Union>
326 constexpr decltype(
auto)
327 __construct_n(_Union& __u)
noexcept
329 if constexpr (_Np == 0)
330 return &__u._M_first;
331 else if constexpr (_Np == 1)
334 return &__u._M_rest._M_first;
336 else if constexpr (_Np == 2)
340 return &__u._M_rest._M_rest._M_first;
347 return __variant::__construct_n<_Np - 3>(__u._M_rest._M_rest._M_rest);
351 template<
typename... _Types>
354 static constexpr bool _S_default_ctor =
355 is_default_constructible_v<
typename _Nth_type<0, _Types...>::type>;
356 static constexpr bool _S_copy_ctor =
357 (is_copy_constructible_v<_Types> && ...);
358 static constexpr bool _S_move_ctor =
359 (is_move_constructible_v<_Types> && ...);
360 static constexpr bool _S_copy_assign =
362 && (is_copy_assignable_v<_Types> && ...);
363 static constexpr bool _S_move_assign =
365 && (is_move_assignable_v<_Types> && ...);
367 static constexpr bool _S_trivial_dtor =
368 (is_trivially_destructible_v<_Types> && ...);
369 static constexpr bool _S_trivial_copy_ctor =
370 (is_trivially_copy_constructible_v<_Types> && ...);
371 static constexpr bool _S_trivial_move_ctor =
372 (is_trivially_move_constructible_v<_Types> && ...);
373 static constexpr bool _S_trivial_copy_assign =
374 _S_trivial_dtor && _S_trivial_copy_ctor
375 && (is_trivially_copy_assignable_v<_Types> && ...);
376 static constexpr bool _S_trivial_move_assign =
377 _S_trivial_dtor && _S_trivial_move_ctor
378 && (is_trivially_move_assignable_v<_Types> && ...);
382 static constexpr bool _S_nothrow_default_ctor =
383 is_nothrow_default_constructible_v<
384 typename _Nth_type<0, _Types...>::type>;
385 static constexpr bool _S_nothrow_copy_ctor =
false;
386 static constexpr bool _S_nothrow_move_ctor =
387 (is_nothrow_move_constructible_v<_Types> && ...);
388 static constexpr bool _S_nothrow_copy_assign =
false;
389 static constexpr bool _S_nothrow_move_assign =
391 && (is_nothrow_move_assignable_v<_Types> && ...);
395 template<
bool __trivially_destructible,
typename... _Types>
396 union _Variadic_union
398 _Variadic_union() =
default;
400 template<
size_t _Np,
typename... _Args>
401 _Variadic_union(in_place_index_t<_Np>, _Args&&...) =
delete;
404 template<
bool __trivially_destructible,
typename _First,
typename... _Rest>
405 union _Variadic_union<__trivially_destructible, _First, _Rest...>
407 constexpr _Variadic_union() : _M_rest() { }
409 template<
typename... _Args>
411 _Variadic_union(in_place_index_t<0>, _Args&&... __args)
412 : _M_first(in_place_index<0>,
std::
forward<_Args>(__args)...)
415 template<
size_t _Np,
typename... _Args>
417 _Variadic_union(in_place_index_t<_Np>, _Args&&... __args)
418 : _M_rest(in_place_index<_Np-1>,
std::
forward<_Args>(__args)...)
421#if __cpp_lib_variant >= 202106L
422 _Variadic_union(
const _Variadic_union&) =
default;
423 _Variadic_union(_Variadic_union&&) =
default;
424 _Variadic_union& operator=(
const _Variadic_union&) =
default;
425 _Variadic_union& operator=(_Variadic_union&&) =
default;
427 ~_Variadic_union() =
default;
429 constexpr ~_Variadic_union()
430 requires (!__trivially_destructible)
434 _Uninitialized<_First> _M_first;
435 _Variadic_union<__trivially_destructible, _Rest...> _M_rest;
443 template<
typename _Tp>
444 struct _Never_valueless_alt
445 : __and_<bool_constant<sizeof(_Tp) <= 256>, is_trivially_copyable<_Tp>>
458 template <typename... _Types>
459 constexpr bool __never_valueless()
461 return _Traits<_Types...>::_S_move_assign
462 && (_Never_valueless_alt<_Types>::value && ...);
466 template<bool __trivially_destructible, typename... _Types>
467 struct _Variant_storage;
469 template <typename... _Types>
470 using __select_index =
471 typename __select_int::_Select_int_base<sizeof...(_Types),
473 unsigned short>::type::value_type;
475 template<typename... _Types>
476 struct _Variant_storage<false, _Types...>
480 : _M_index(static_cast<__index_type>(variant_npos))
483 template<size_t _Np, typename... _Args>
485 _Variant_storage(in_place_index_t<_Np>, _Args&&... __args)
486 : _M_u(in_place_index<_Np>, std::forward<_Args>(__args)...),
493 if (!_M_valid()) [[unlikely]]
496 std::__do_visit<void>([](auto&& __this_mem) mutable
498 std::_Destroy(std::__addressof(__this_mem));
499 }, __variant_cast<_Types...>(*this));
501 _M_index = static_cast<__index_type>(variant_npos);
509 _M_valid() const noexcept
511 if constexpr (__variant::__never_valueless<_Types...>())
513 return this->_M_index != __index_type(variant_npos);
516 _Variadic_union<false, _Types...> _M_u;
517 using __index_type = __select_index<_Types...>;
518 __index_type _M_index;
521 template<typename... _Types>
522 struct _Variant_storage<true, _Types...>
526 : _M_index(static_cast<__index_type>(variant_npos))
529 template<
size_t _Np,
typename... _Args>
531 _Variant_storage(in_place_index_t<_Np>, _Args&&... __args)
532 : _M_u(in_place_index<_Np>,
std::
forward<_Args>(__args)...),
538 { _M_index =
static_cast<__index_type
>(variant_npos); }
541 _M_valid() const noexcept
543 if constexpr (__variant::__never_valueless<_Types...>())
551 return this->_M_index !=
static_cast<__index_type
>(variant_npos);
554 _Variadic_union<
true, _Types...> _M_u;
555 using __index_type = __select_index<_Types...>;
556 __index_type _M_index;
560 template<
size_t _Np,
bool _Triv,
typename... _Types,
typename... _Args>
563 __emplace(_Variant_storage<_Triv, _Types...>& __v, _Args&&... __args)
566 auto* __addr = __variant::__construct_n<_Np>(__v._M_u);
568 std::forward<_Args>(__args)...);
573 template<
typename... _Types>
574 using _Variant_storage_alias =
575 _Variant_storage<_Traits<_Types...>::_S_trivial_dtor, _Types...>;
580 template<bool,
typename... _Types>
581 struct _Copy_ctor_base : _Variant_storage_alias<_Types...>
583 using _Base = _Variant_storage_alias<_Types...>;
587 _Copy_ctor_base(
const _Copy_ctor_base& __rhs)
588 noexcept(_Traits<_Types...>::_S_nothrow_copy_ctor)
590 __variant::__raw_idx_visit(
591 [
this](
auto&& __rhs_mem,
auto __rhs_index)
mutable
593 constexpr size_t __j = __rhs_index;
594 if constexpr (__j != variant_npos)
596 in_place_index<__j>, __rhs_mem);
597 }, __variant_cast<_Types...>(__rhs));
598 this->_M_index = __rhs._M_index;
601 _Copy_ctor_base(_Copy_ctor_base&&) =
default;
602 _Copy_ctor_base& operator=(
const _Copy_ctor_base&) =
default;
603 _Copy_ctor_base& operator=(_Copy_ctor_base&&) =
default;
606 template<
typename... _Types>
607 struct _Copy_ctor_base<true, _Types...> : _Variant_storage_alias<_Types...>
609 using _Base = _Variant_storage_alias<_Types...>;
613 template<
typename... _Types>
614 using _Copy_ctor_alias =
615 _Copy_ctor_base<_Traits<_Types...>::_S_trivial_copy_ctor, _Types...>;
617 template<bool,
typename... _Types>
618 struct _Move_ctor_base : _Copy_ctor_alias<_Types...>
620 using _Base = _Copy_ctor_alias<_Types...>;
624 _Move_ctor_base(_Move_ctor_base&& __rhs)
625 noexcept(_Traits<_Types...>::_S_nothrow_move_ctor)
627 __variant::__raw_idx_visit(
628 [
this](
auto&& __rhs_mem,
auto __rhs_index)
mutable
630 constexpr size_t __j = __rhs_index;
631 if constexpr (__j != variant_npos)
635 }, __variant_cast<_Types...>(
std::move(__rhs)));
636 this->_M_index = __rhs._M_index;
639 _Move_ctor_base(
const _Move_ctor_base&) =
default;
640 _Move_ctor_base& operator=(
const _Move_ctor_base&) =
default;
641 _Move_ctor_base& operator=(_Move_ctor_base&&) =
default;
644 template<
typename... _Types>
645 struct _Move_ctor_base<true, _Types...> : _Copy_ctor_alias<_Types...>
647 using _Base = _Copy_ctor_alias<_Types...>;
651 template<
typename... _Types>
652 using _Move_ctor_alias =
653 _Move_ctor_base<_Traits<_Types...>::_S_trivial_move_ctor, _Types...>;
655 template<bool,
typename... _Types>
656 struct _Copy_assign_base : _Move_ctor_alias<_Types...>
658 using _Base = _Move_ctor_alias<_Types...>;
663 operator=(
const _Copy_assign_base& __rhs)
664 noexcept(_Traits<_Types...>::_S_nothrow_copy_assign)
666 __variant::__raw_idx_visit(
667 [
this](
auto&& __rhs_mem,
auto __rhs_index)
mutable
669 constexpr size_t __j = __rhs_index;
670 if constexpr (__j == variant_npos)
672 else if (this->_M_index == __j)
673 __variant::__get<__j>(*
this) = __rhs_mem;
676 using _Tj =
typename _Nth_type<__j, _Types...>::type;
677 if constexpr (is_nothrow_copy_constructible_v<_Tj>
678 || !is_nothrow_move_constructible_v<_Tj>)
679 __variant::__emplace<__j>(*
this, __rhs_mem);
682 using _Variant = variant<_Types...>;
683 _Variant& __self = __variant_cast<_Types...>(*this);
684 __self = _Variant(in_place_index<__j>, __rhs_mem);
687 }, __variant_cast<_Types...>(__rhs));
691 _Copy_assign_base(
const _Copy_assign_base&) =
default;
692 _Copy_assign_base(_Copy_assign_base&&) =
default;
693 _Copy_assign_base& operator=(_Copy_assign_base&&) =
default;
696 template<
typename... _Types>
697 struct _Copy_assign_base<true, _Types...> : _Move_ctor_alias<_Types...>
699 using _Base = _Move_ctor_alias<_Types...>;
703 template<
typename... _Types>
704 using _Copy_assign_alias =
705 _Copy_assign_base<_Traits<_Types...>::_S_trivial_copy_assign, _Types...>;
707 template<bool,
typename... _Types>
708 struct _Move_assign_base : _Copy_assign_alias<_Types...>
710 using _Base = _Copy_assign_alias<_Types...>;
715 operator=(_Move_assign_base&& __rhs)
716 noexcept(_Traits<_Types...>::_S_nothrow_move_assign)
718 __variant::__raw_idx_visit(
719 [
this](
auto&& __rhs_mem,
auto __rhs_index)
mutable
721 constexpr size_t __j = __rhs_index;
722 if constexpr (__j != variant_npos)
724 if (this->_M_index == __j)
725 __variant::__get<__j>(*
this) =
std::move(__rhs_mem);
728 using _Tj =
typename _Nth_type<__j, _Types...>::type;
729 if constexpr (is_nothrow_move_constructible_v<_Tj>)
730 __variant::__emplace<__j>(*
this,
std::move(__rhs_mem));
733 using _Variant = variant<_Types...>;
734 _Variant& __self = __variant_cast<_Types...>(*this);
735 __self.template emplace<__j>(
std::move(__rhs_mem));
741 }, __variant_cast<_Types...>(__rhs));
745 _Move_assign_base(
const _Move_assign_base&) =
default;
746 _Move_assign_base(_Move_assign_base&&) =
default;
747 _Move_assign_base& operator=(
const _Move_assign_base&) =
default;
750 template<
typename... _Types>
751 struct _Move_assign_base<true, _Types...> : _Copy_assign_alias<_Types...>
753 using _Base = _Copy_assign_alias<_Types...>;
757 template<
typename... _Types>
758 using _Move_assign_alias =
759 _Move_assign_base<_Traits<_Types...>::_S_trivial_move_assign, _Types...>;
761 template<
typename... _Types>
762 struct _Variant_base : _Move_assign_alias<_Types...>
764 using _Base = _Move_assign_alias<_Types...>;
767 _Variant_base() noexcept(_Traits<_Types...>::_S_nothrow_default_ctor)
768 : _Variant_base(in_place_index<0>) { }
770 template<
size_t _Np,
typename... _Args>
772 _Variant_base(in_place_index_t<_Np> __i, _Args&&... __args)
776 _Variant_base(
const _Variant_base&) =
default;
777 _Variant_base(_Variant_base&&) =
default;
778 _Variant_base& operator=(
const _Variant_base&) =
default;
779 _Variant_base& operator=(_Variant_base&&) =
default;
782 template<
typename _Tp,
typename... _Types>
783 inline constexpr bool __exactly_once
784 = std::__find_uniq_type_in_pack<_Tp, _Types...>() <
sizeof...(_Types);
787 template<
typename _Ti>
struct _Arr { _Ti _M_x[1]; };
790 template<
size_t _Ind,
typename _Tp,
typename _Ti,
typename =
void>
795 void _S_fun() =
delete;
799 template<
size_t _Ind,
typename _Tp,
typename _Ti>
800 struct _Build_FUN<_Ind, _Tp, _Ti,
801 void_t<decltype(_Arr<_Ti>{{std::declval<_Tp>()}})>>
804 static integral_constant<size_t, _Ind> _S_fun(_Ti);
807 template<
typename _Tp,
typename _Variant,
808 typename = make_index_sequence<variant_size_v<_Variant>>>
811 template<
typename _Tp,
typename... _Ti,
size_t... _Ind>
813 : _Build_FUN<_Ind, _Tp, _Ti>...
815 using _Build_FUN<_Ind, _Tp, _Ti>::_S_fun...;
820 template<
typename _Tp,
typename _Variant>
822 =
decltype(_Build_FUNs<_Tp, _Variant>::_S_fun(std::declval<_Tp>()));
825 template<
typename _Tp,
typename _Variant,
typename =
void>
826 inline constexpr size_t
827 __accepted_index = variant_npos;
829 template<
typename _Tp,
typename _Variant>
830 inline constexpr size_t
831 __accepted_index<_Tp, _Variant, void_t<_FUN_type<_Tp, _Variant>>>
832 = _FUN_type<_Tp, _Variant>::value;
834 template<
typename _Maybe_variant_cookie,
typename _Variant,
835 typename = __remove_cvref_t<_Variant>>
836 inline constexpr bool
837 __extra_visit_slot_needed =
false;
839 template<
typename _Var,
typename... _Types>
840 inline constexpr bool
841 __extra_visit_slot_needed<__variant_cookie, _Var, variant<_Types...>>
842 = !__variant::__never_valueless<_Types...>();
844 template<
typename _Var,
typename... _Types>
845 inline constexpr bool
846 __extra_visit_slot_needed<__variant_idx_cookie, _Var, variant<_Types...>>
847 = !__variant::__never_valueless<_Types...>();
850 template<
typename _Tp,
size_t... _Dimensions>
854 template<
typename _Tp>
855 struct _Multi_array<_Tp>
858 struct __untag_result
860 {
using element_type = _Tp; };
862#pragma GCC diagnostic push
863#pragma GCC diagnostic ignored "-Wignored-qualifiers"
864 template <
typename... _Args>
865 struct __untag_result<const void(*)(_Args...)>
867 {
using element_type = void(*)(_Args...); };
868#pragma GCC diagnostic pop
870 template <
typename... _Args>
871 struct __untag_result<__variant_cookie(*)(_Args...)>
873 {
using element_type = void(*)(_Args...); };
875 template <
typename... _Args>
876 struct __untag_result<__variant_idx_cookie(*)(_Args...)>
878 {
using element_type = void(*)(_Args...); };
880 template <
typename _Res,
typename... _Args>
881 struct __untag_result<__deduce_visit_result<_Res>(*)(_Args...)>
883 {
using element_type = _Res(*)(_Args...); };
885 using __result_is_deduced = __untag_result<_Tp>;
887 constexpr const typename __untag_result<_Tp>::element_type&
891 typename __untag_result<_Tp>::element_type _M_data;
895 template<
typename _Ret,
897 typename... _Variants,
898 size_t __first,
size_t... __rest>
899 struct _Multi_array<_Ret(*)(_Visitor, _Variants...), __first, __rest...>
901 static constexpr size_t __index =
902 sizeof...(_Variants) -
sizeof...(__rest) - 1;
904 using _Variant =
typename _Nth_type<__index, _Variants...>::type;
906 static constexpr int __do_cookie =
907 __extra_visit_slot_needed<_Ret, _Variant> ? 1 : 0;
909 using _Tp = _Ret(*)(_Visitor, _Variants...);
911 template<
typename... _Args>
912 constexpr decltype(
auto)
913 _M_access(
size_t __first_index, _Args... __rest_indices)
const
915 return _M_arr[__first_index + __do_cookie]
916 ._M_access(__rest_indices...);
919 _Multi_array<_Tp, __rest...> _M_arr[__first + __do_cookie];
949 template<
typename _Array_type,
typename _Index_seq>
950 struct __gen_vtable_impl;
959 template<
typename _Result_type,
typename _Visitor,
size_t... __dimensions,
960 typename... _Variants,
size_t... __indices>
961 struct __gen_vtable_impl<
962 _Multi_array<_Result_type (*)(_Visitor, _Variants...), __dimensions...>,
967 _Variants...>::type>;
969 _Multi_array<_Result_type (*)(_Visitor, _Variants...),
972 static constexpr _Array_type
975 _Array_type __vtable{};
981 template<
size_t... __var_indices>
982 static constexpr void
983 _S_apply_all_alts(_Array_type& __vtable,
986 if constexpr (__extra_visit_slot_needed<_Result_type, _Next>)
987 (_S_apply_single_alt<true, __var_indices>(
988 __vtable._M_arr[__var_indices + 1],
989 &(__vtable._M_arr[0])), ...);
991 (_S_apply_single_alt<false, __var_indices>(
992 __vtable._M_arr[__var_indices]), ...);
995 template<
bool __do_cookie,
size_t __index,
typename _Tp>
996 static constexpr void
997 _S_apply_single_alt(_Tp& __element, _Tp* __cookie_element =
nullptr)
999 if constexpr (__do_cookie)
1001 __element = __gen_vtable_impl<
1004 *__cookie_element = __gen_vtable_impl<
1010 auto __tmp_element = __gen_vtable_impl<
1013 static_assert(is_same_v<_Tp,
decltype(__tmp_element)>,
1014 "std::visit requires the visitor to have the same "
1015 "return type for all alternatives of a variant");
1016 __element = __tmp_element;
1024 template<
typename _Result_type,
typename _Visitor,
typename... _Variants,
1025 size_t... __indices>
1026 struct __gen_vtable_impl<
1027 _Multi_array<_Result_type (*)(_Visitor, _Variants...)>,
1031 _Multi_array<_Result_type (*)(_Visitor, _Variants...)>;
1033 template<
size_t __index,
typename _Variant>
1034 static constexpr decltype(
auto)
1035 __element_by_index_or_cookie(_Variant&& __var)
noexcept
1037 if constexpr (__index != variant_npos)
1038 return __variant::__get<__index>(std::forward<_Variant>(__var));
1040 return __variant_cookie{};
1043 static constexpr decltype(
auto)
1044 __visit_invoke(_Visitor&& __visitor, _Variants... __vars)
1046 if constexpr (is_same_v<_Result_type, __variant_idx_cookie>)
1050 __element_by_index_or_cookie<__indices>(
1051 std::forward<_Variants>(__vars))...,
1052 integral_constant<size_t, __indices>()...);
1053 else if constexpr (is_same_v<_Result_type, __variant_cookie>)
1056 __element_by_index_or_cookie<__indices>(
1057 std::forward<_Variants>(__vars))...);
1058 else if constexpr (_Array_type::__result_is_deduced::value)
1061 __element_by_index_or_cookie<__indices>(
1062 std::forward<_Variants>(__vars))...);
1064 return std::__invoke_r<_Result_type>(
1065 std::forward<_Visitor>(__visitor),
1066 __variant::__get<__indices>(std::forward<_Variants>(__vars))...);
1069 static constexpr auto
1072 if constexpr (_Array_type::__result_is_deduced::value)
1074 constexpr bool __visit_ret_type_mismatch =
1075 !is_same_v<
typename _Result_type::type,
1076 decltype(__visit_invoke(std::declval<_Visitor>(),
1077 std::declval<_Variants>()...))>;
1078 if constexpr (__visit_ret_type_mismatch)
1080 struct __cannot_match {};
1081 return __cannot_match{};
1084 return _Array_type{&__visit_invoke};
1087 return _Array_type{&__visit_invoke};
1091 template<
typename _Result_type,
typename _Visitor,
typename... _Variants>
1095 _Multi_array<_Result_type (*)(_Visitor, _Variants...),
1096 variant_size_v<remove_reference_t<_Variants>>...>;
1098 static constexpr _Array_type _S_vtable
1099 = __gen_vtable_impl<_Array_type, std::index_sequence<>>::_S_apply();
1102 template<
size_t _Np,
typename _Tp>
1103 struct _Base_dedup :
public _Tp { };
1105 template<
typename _Variant,
typename __indices>
1106 struct _Variant_hash_base;
1108 template<
typename... _Types,
size_t... __indices>
1109 struct _Variant_hash_base<variant<_Types...>,
1111 : _Base_dedup<__indices, __poison_hash<remove_const_t<_Types>>>... { };
1114 template<
size_t _Np,
typename _Variant,
1115 typename _AsV =
decltype(__variant::__as(std::declval<_Variant>())),
1116 typename _Tp = variant_alternative_t<_Np, remove_reference_t<_AsV>>>
1118 = __conditional_t<is_lvalue_reference_v<_Variant>, _Tp&, _Tp&&>;
1121 template<
typename _Visitor,
typename... _Variants>
1122 using __visit_result_t
1123 = invoke_result_t<_Visitor, __get_t<0, _Variants>...>;
1125 template<
typename _Tp,
typename... _Types>
1126 constexpr inline bool __same_types = (is_same_v<_Tp, _Types> && ...);
1128 template <
typename _Visitor,
typename _Variant,
size_t... _Idxs>
1131 return __same_types<
1132 invoke_result_t<_Visitor, __get_t<_Idxs, _Variant>>...
1139 template<
typename _Tp,
typename... _Types>
1141 holds_alternative(
const variant<_Types...>& __v)
noexcept
1143 static_assert(__detail::__variant::__exactly_once<_Tp, _Types...>,
1144 "T must occur exactly once in alternatives");
1145 return __v.index() == std::__find_uniq_type_in_pack<_Tp, _Types...>();
1148 template<
typename _Tp,
typename... _Types>
1150 get(variant<_Types...>& __v)
1152 static_assert(__detail::__variant::__exactly_once<_Tp, _Types...>,
1153 "T must occur exactly once in alternatives");
1154 constexpr size_t __n = std::__find_uniq_type_in_pack<_Tp, _Types...>();
1155 return std::get<__n>(__v);
1158 template<
typename _Tp,
typename... _Types>
1160 get(variant<_Types...>&& __v)
1162 static_assert(__detail::__variant::__exactly_once<_Tp, _Types...>,
1163 "T must occur exactly once in alternatives");
1164 constexpr size_t __n = std::__find_uniq_type_in_pack<_Tp, _Types...>();
1168 template<
typename _Tp,
typename... _Types>
1169 constexpr const _Tp&
1170 get(
const variant<_Types...>& __v)
1172 static_assert(__detail::__variant::__exactly_once<_Tp, _Types...>,
1173 "T must occur exactly once in alternatives");
1174 constexpr size_t __n = std::__find_uniq_type_in_pack<_Tp, _Types...>();
1175 return std::get<__n>(__v);
1178 template<
typename _Tp,
typename... _Types>
1179 constexpr const _Tp&&
1180 get(
const variant<_Types...>&& __v)
1182 static_assert(__detail::__variant::__exactly_once<_Tp, _Types...>,
1183 "T must occur exactly once in alternatives");
1184 constexpr size_t __n = std::__find_uniq_type_in_pack<_Tp, _Types...>();
1188 template<
size_t _Np,
typename... _Types>
1189 constexpr add_pointer_t<variant_alternative_t<_Np, variant<_Types...>>>
1190 get_if(variant<_Types...>* __ptr)
noexcept
1192 using _Alternative_type = variant_alternative_t<_Np, variant<_Types...>>;
1193 static_assert(_Np <
sizeof...(_Types),
1194 "The index must be in [0, number of alternatives)");
1195 static_assert(!is_void_v<_Alternative_type>,
"_Tp must not be void");
1196 if (__ptr && __ptr->index() == _Np)
1201 template<
size_t _Np,
typename... _Types>
1203 add_pointer_t<
const variant_alternative_t<_Np, variant<_Types...>>>
1204 get_if(
const variant<_Types...>* __ptr)
noexcept
1206 using _Alternative_type = variant_alternative_t<_Np, variant<_Types...>>;
1207 static_assert(_Np <
sizeof...(_Types),
1208 "The index must be in [0, number of alternatives)");
1209 static_assert(!is_void_v<_Alternative_type>,
"_Tp must not be void");
1210 if (__ptr && __ptr->index() == _Np)
1215 template<
typename _Tp,
typename... _Types>
1216 constexpr add_pointer_t<_Tp>
1217 get_if(variant<_Types...>* __ptr)
noexcept
1219 static_assert(__detail::__variant::__exactly_once<_Tp, _Types...>,
1220 "T must occur exactly once in alternatives");
1221 static_assert(!is_void_v<_Tp>,
"_Tp must not be void");
1222 constexpr size_t __n = std::__find_uniq_type_in_pack<_Tp, _Types...>();
1223 return std::get_if<__n>(__ptr);
1226 template<
typename _Tp,
typename... _Types>
1227 constexpr add_pointer_t<const _Tp>
1228 get_if(
const variant<_Types...>* __ptr)
noexcept
1230 static_assert(__detail::__variant::__exactly_once<_Tp, _Types...>,
1231 "T must occur exactly once in alternatives");
1232 static_assert(!is_void_v<_Tp>,
"_Tp must not be void");
1233 constexpr size_t __n = std::__find_uniq_type_in_pack<_Tp, _Types...>();
1234 return std::get_if<__n>(__ptr);
1237 struct monostate { };
1239#define _VARIANT_RELATION_FUNCTION_TEMPLATE(__OP, __NAME) \
1240 template<typename... _Types> \
1241 constexpr bool operator __OP(const variant<_Types...>& __lhs, \
1242 const variant<_Types...>& __rhs) \
1244 bool __ret = true; \
1245 __detail::__variant::__raw_idx_visit( \
1246 [&__ret, &__lhs] (auto&& __rhs_mem, auto __rhs_index) mutable \
1248 if constexpr (__rhs_index != variant_npos) \
1250 if (__lhs.index() == __rhs_index) \
1252 auto& __this_mem = std::get<__rhs_index>(__lhs); \
1253 __ret = __this_mem __OP __rhs_mem; \
1256 __ret = (__lhs.index() + 1) __OP (__rhs_index + 1); \
1259 __ret = (__lhs.index() + 1) __OP (__rhs_index + 1); \
1264 _VARIANT_RELATION_FUNCTION_TEMPLATE(<, less)
1265 _VARIANT_RELATION_FUNCTION_TEMPLATE(<=, less_equal)
1266 _VARIANT_RELATION_FUNCTION_TEMPLATE(==, equal)
1267 _VARIANT_RELATION_FUNCTION_TEMPLATE(!=, not_equal)
1268 _VARIANT_RELATION_FUNCTION_TEMPLATE(>=, greater_equal)
1269 _VARIANT_RELATION_FUNCTION_TEMPLATE(>, greater)
1271#undef _VARIANT_RELATION_FUNCTION_TEMPLATE
1273 constexpr bool operator==(monostate, monostate)
noexcept {
return true; }
1275#ifdef __cpp_lib_three_way_comparison
1276 template<
typename... _Types>
1277 requires (three_way_comparable<_Types> && ...)
1279 common_comparison_category_t<compare_three_way_result_t<_Types>...>
1280 operator<=>(
const variant<_Types...>& __v,
const variant<_Types...>& __w)
1282 common_comparison_category_t<compare_three_way_result_t<_Types>...> __ret
1283 = strong_ordering::equal;
1285 __detail::__variant::__raw_idx_visit(
1286 [&__ret, &__v] (
auto&& __w_mem,
auto __w_index)
mutable
1288 if constexpr (__w_index != variant_npos)
1290 if (__v.index() == __w_index)
1292 auto& __this_mem = std::get<__w_index>(__v);
1293 __ret = __this_mem <=> __w_mem;
1297 __ret = (__v.index() + 1) <=> (__w_index + 1);
1302 constexpr strong_ordering
1303 operator<=>(monostate, monostate)
noexcept {
return strong_ordering::equal; }
1305 constexpr bool operator!=(monostate, monostate)
noexcept {
return false; }
1306 constexpr bool operator<(monostate, monostate)
noexcept {
return false; }
1307 constexpr bool operator>(monostate, monostate)
noexcept {
return false; }
1308 constexpr bool operator<=(monostate, monostate)
noexcept {
return true; }
1309 constexpr bool operator>=(monostate, monostate)
noexcept {
return true; }
1312 template<
typename _Visitor,
typename... _Variants>
1313 constexpr __detail::__variant::__visit_result_t<_Visitor, _Variants...>
1314 visit(_Visitor&&, _Variants&&...);
1316 template<
typename... _Types>
1317 _GLIBCXX20_CONSTEXPR
1318 inline enable_if_t<(is_move_constructible_v<_Types> && ...)
1319 && (is_swappable_v<_Types> && ...)>
1320 swap(variant<_Types...>& __lhs, variant<_Types...>& __rhs)
1321 noexcept(
noexcept(__lhs.swap(__rhs)))
1322 { __lhs.swap(__rhs); }
1324 template<
typename... _Types>
1325 enable_if_t<!((is_move_constructible_v<_Types> && ...)
1326 && (is_swappable_v<_Types> && ...))>
1327 swap(variant<_Types...>&, variant<_Types...>&) =
delete;
1329 class bad_variant_access :
public exception
1332 bad_variant_access() noexcept { }
1334 const char* what() const noexcept
override
1335 {
return _M_reason; }
1338 bad_variant_access(
const char* __reason) noexcept : _M_reason(__reason) { }
1341 const char* _M_reason =
"bad variant access";
1343 friend void __throw_bad_variant_access(
const char* __what);
1348 __throw_bad_variant_access(
const char* __what)
1349 { _GLIBCXX_THROW_OR_ABORT(bad_variant_access(__what)); }
1352 __throw_bad_variant_access(
bool __valueless)
1354 if (__valueless) [[__unlikely__]]
1355 __throw_bad_variant_access(
"std::get: variant is valueless");
1357 __throw_bad_variant_access(
"std::get: wrong index for variant");
1360 template<
typename... _Types>
1362 :
private __detail::__variant::_Variant_base<_Types...>,
1363 private _Enable_copy_move<
1364 __detail::__variant::_Traits<_Types...>::_S_copy_ctor,
1365 __detail::__variant::_Traits<_Types...>::_S_copy_assign,
1366 __detail::__variant::_Traits<_Types...>::_S_move_ctor,
1367 __detail::__variant::_Traits<_Types...>::_S_move_assign,
1371 template <
typename... _UTypes,
typename _Tp>
1372 friend _GLIBCXX20_CONSTEXPR
decltype(
auto)
1373 __variant_cast(_Tp&&);
1375 static_assert(
sizeof...(_Types) > 0,
1376 "variant must have at least one alternative");
1377 static_assert(!(std::is_reference_v<_Types> || ...),
1378 "variant must have no reference alternative");
1379 static_assert(!(std::is_void_v<_Types> || ...),
1380 "variant must have no void alternative");
1382 using _Base = __detail::__variant::_Variant_base<_Types...>;
1384 template<
typename _Tp>
1385 static constexpr bool __not_self
1386 = !is_same_v<__remove_cvref_t<_Tp>, variant>;
1388 template<
typename _Tp>
1389 static constexpr bool
1390 __exactly_once = __detail::__variant::__exactly_once<_Tp, _Types...>;
1392 template<
typename _Tp>
1393 static constexpr size_t __accepted_index
1394 = __detail::__variant::__accepted_index<_Tp, variant>;
1396 template<
size_t _Np,
typename =
enable_if_t<(_Np <
sizeof...(_Types))>>
1397 using __to_type =
typename _Nth_type<_Np, _Types...>::type;
1399 template<
typename _Tp,
typename = enable_if_t<__not_self<_Tp>>>
1400 using __accepted_type = __to_type<__accepted_index<_Tp>>;
1402 template<
typename _Tp>
1403 static constexpr size_t __index_of
1404 = std::__find_uniq_type_in_pack<_Tp, _Types...>();
1406 using _Traits = __detail::__variant::_Traits<_Types...>;
1408 template<
typename _Tp>
1410 template<
typename _Tp>
1411 struct __is_in_place_tag<in_place_type_t<_Tp>> :
true_type { };
1412 template<
size_t _Np>
1413 struct __is_in_place_tag<in_place_index_t<_Np>> :
true_type { };
1415 template<
typename _Tp>
1416 static constexpr bool __not_in_place_tag
1417 = !__is_in_place_type_v<__remove_cvref_t<_Tp>>
1418 && !__is_in_place_index_v<__remove_cvref_t<_Tp>>;
1422 variant()
requires is_default_constructible_v<__to_type<0>> = default;
1424 template<
typename _Tp0 = __to_type<0>,
1425 typename = enable_if_t<is_default_constructible_v<_Tp0>>>
1427 variant() noexcept(is_nothrow_default_constructible_v<__to_type<0>>)
1431 variant(
const variant& __rhs) =
default;
1432 variant(variant&&) =
default;
1433 variant& operator=(
const variant&) =
default;
1434 variant& operator=(variant&&) =
default;
1435 _GLIBCXX20_CONSTEXPR ~variant() =
default;
1437 template<
typename _Tp,
1439 typename = enable_if_t<__not_in_place_tag<_Tp>>,
1440 typename _Tj = __accepted_type<_Tp&&>,
1441 typename = enable_if_t<__exactly_once<_Tj>
1442 && is_constructible_v<_Tj, _Tp>>>
1445 noexcept(is_nothrow_constructible_v<_Tj, _Tp>)
1446 : variant(in_place_index<__accepted_index<_Tp>>,
1450 template<
typename _Tp,
typename... _Args,
1451 typename = enable_if_t<__exactly_once<_Tp>
1452 && is_constructible_v<_Tp, _Args...>>>
1454 variant(in_place_type_t<_Tp>, _Args&&... __args)
1455 : variant(in_place_index<__index_of<_Tp>>,
1459 template<
typename _Tp,
typename _Up,
typename... _Args,
1460 typename = enable_if_t<__exactly_once<_Tp>
1461 && is_constructible_v<_Tp,
1462 initializer_list<_Up>&, _Args...>>>
1464 variant(in_place_type_t<_Tp>, initializer_list<_Up> __il,
1466 : variant(in_place_index<__index_of<_Tp>>, __il,
1470 template<
size_t _Np,
typename... _Args,
1471 typename _Tp = __to_type<_Np>,
1472 typename =
enable_if_t<is_constructible_v<_Tp, _Args...>>>
1474 variant(in_place_index_t<_Np>, _Args&&... __args)
1475 : _Base(in_place_index<_Np>,
std::
forward<_Args>(__args)...)
1478 template<
size_t _Np,
typename _Up,
typename... _Args,
1479 typename _Tp = __to_type<_Np>,
1481 initializer_list<_Up>&,
1484 variant(in_place_index_t<_Np>, initializer_list<_Up> __il,
1486 : _Base(in_place_index<_Np>, __il,
std::
forward<_Args>(__args)...)
1489 template<
typename _Tp>
1490 _GLIBCXX20_CONSTEXPR
1491 enable_if_t<__exactly_once<__accepted_type<_Tp&&>>
1492 && is_constructible_v<__accepted_type<_Tp&&>, _Tp>
1493 && is_assignable_v<__accepted_type<_Tp&&>&, _Tp>,
1495 operator=(_Tp&& __rhs)
1496 noexcept(is_nothrow_assignable_v<__accepted_type<_Tp&&>&, _Tp>
1497 && is_nothrow_constructible_v<__accepted_type<_Tp&&>, _Tp>)
1499 constexpr auto __index = __accepted_index<_Tp>;
1500 if (index() == __index)
1501 std::get<__index>(*
this) = std::forward<_Tp>(__rhs);
1504 using _Tj = __accepted_type<_Tp&&>;
1505 if constexpr (is_nothrow_constructible_v<_Tj, _Tp>
1506 || !is_nothrow_move_constructible_v<_Tj>)
1507 this->emplace<__index>(std::forward<_Tp>(__rhs));
1511 this->emplace<__index>(_Tj(std::forward<_Tp>(__rhs)));
1516 template<
typename _Tp,
typename... _Args>
1517 _GLIBCXX20_CONSTEXPR
1518 enable_if_t<is_constructible_v<_Tp, _Args...> && __exactly_once<_Tp>,
1520 emplace(_Args&&... __args)
1522 constexpr size_t __index = __index_of<_Tp>;
1523 return this->emplace<__index>(std::forward<_Args>(__args)...);
1526 template<
typename _Tp,
typename _Up,
typename... _Args>
1527 _GLIBCXX20_CONSTEXPR
1528 enable_if_t<is_constructible_v<_Tp, initializer_list<_Up>&, _Args...>
1529 && __exactly_once<_Tp>,
1531 emplace(initializer_list<_Up> __il, _Args&&... __args)
1533 constexpr size_t __index = __index_of<_Tp>;
1534 return this->emplace<__index>(__il, std::forward<_Args>(__args)...);
1537 template<
size_t _Np,
typename... _Args>
1538 _GLIBCXX20_CONSTEXPR
1539 enable_if_t<is_constructible_v<__to_type<_Np>, _Args...>,
1541 emplace(_Args&&... __args)
1543 namespace __variant = std::__detail::__variant;
1544 using type =
typename _Nth_type<_Np, _Types...>::type;
1547 if constexpr (is_nothrow_constructible_v<type, _Args...>)
1549 __variant::__emplace<_Np>(*
this, std::forward<_Args>(__args)...);
1551 else if constexpr (is_scalar_v<type>)
1554 const type __tmp(std::forward<_Args>(__args)...);
1556 __variant::__emplace<_Np>(*
this, __tmp);
1558 else if constexpr (__variant::_Never_valueless_alt<type>()
1559 && _Traits::_S_move_assign)
1562 variant __tmp(in_place_index<_Np>,
1563 std::forward<_Args>(__args)...);
1571 __variant::__emplace<_Np>(*
this, std::forward<_Args>(__args)...);
1573 return std::get<_Np>(*
this);
1576 template<
size_t _Np,
typename _Up,
typename... _Args>
1577 _GLIBCXX20_CONSTEXPR
1578 enable_if_t<is_constructible_v<__to_type<_Np>,
1579 initializer_list<_Up>&, _Args...>,
1581 emplace(initializer_list<_Up> __il, _Args&&... __args)
1583 namespace __variant = std::__detail::__variant;
1584 using type =
typename _Nth_type<_Np, _Types...>::type;
1587 if constexpr (is_nothrow_constructible_v<type,
1588 initializer_list<_Up>&,
1591 __variant::__emplace<_Np>(*
this, __il,
1592 std::forward<_Args>(__args)...);
1594 else if constexpr (__variant::_Never_valueless_alt<type>()
1595 && _Traits::_S_move_assign)
1598 variant __tmp(in_place_index<_Np>, __il,
1599 std::forward<_Args>(__args)...);
1607 __variant::__emplace<_Np>(*
this, __il,
1608 std::forward<_Args>(__args)...);
1610 return std::get<_Np>(*
this);
1613 template<
size_t _Np,
typename... _Args>
1614 enable_if_t<!(_Np <
sizeof...(_Types))> emplace(_Args&&...) =
delete;
1616 template<
typename _Tp,
typename... _Args>
1617 enable_if_t<!__exactly_once<_Tp>> emplace(_Args&&...) =
delete;
1619 constexpr bool valueless_by_exception() const noexcept
1620 {
return !this->_M_valid(); }
1622 constexpr size_t index() const noexcept
1624 using __index_type =
typename _Base::__index_type;
1625 if constexpr (__detail::__variant::__never_valueless<_Types...>())
1626 return this->_M_index;
1627 else if constexpr (
sizeof...(_Types) <= __index_type(-1) / 2)
1628 return make_signed_t<__index_type>(this->_M_index);
1630 return size_t(__index_type(this->_M_index + 1)) - 1;
1633 _GLIBCXX20_CONSTEXPR
1635 swap(variant& __rhs)
1636 noexcept((__is_nothrow_swappable<_Types>::value && ...)
1637 && is_nothrow_move_constructible_v<variant>)
1639 static_assert((is_move_constructible_v<_Types> && ...));
1642 if (__rhs.valueless_by_exception()) [[__unlikely__]]
1644 if (!this->valueless_by_exception()) [[__likely__]]
1649 namespace __variant = __detail::__variant;
1651 __variant::__raw_idx_visit(
1652 [
this, &__rhs](
auto&& __rhs_mem,
auto __rhs_index)
mutable
1654 constexpr size_t __j = __rhs_index;
1655 if constexpr (__j != variant_npos)
1657 if (this->index() == __j)
1660 swap(std::get<__j>(*
this), __rhs_mem);
1666 if constexpr (_Traits::_S_trivial_move_assign)
1669 __variant::__raw_idx_visit(
1670 [&__rhs](
auto&& __this_mem,
auto __this_index)
mutable
1672 constexpr size_t __k = __this_index;
1673 if constexpr (__k != variant_npos)
1674 __variant::__emplace<__k>(__rhs,
1678 __variant::__emplace<__j>(*
this,
std::move(__tmp));
1684#if defined(__clang__) && __clang_major__ <= 7
1690 template<
size_t _Np,
typename _Vp>
1691 friend constexpr decltype(
auto)
1692 __detail::__variant::__get(_Vp&& __v)
noexcept;
1694#define _VARIANT_RELATION_FUNCTION_TEMPLATE(__OP) \
1695 template<typename... _Tp> \
1696 friend constexpr bool \
1697 operator __OP(const variant<_Tp...>& __lhs, \
1698 const variant<_Tp...>& __rhs);
1700 _VARIANT_RELATION_FUNCTION_TEMPLATE(<)
1701 _VARIANT_RELATION_FUNCTION_TEMPLATE(<=)
1702 _VARIANT_RELATION_FUNCTION_TEMPLATE(==)
1703 _VARIANT_RELATION_FUNCTION_TEMPLATE(!=)
1704 _VARIANT_RELATION_FUNCTION_TEMPLATE(>=)
1705 _VARIANT_RELATION_FUNCTION_TEMPLATE(>)
1707#undef _VARIANT_RELATION_FUNCTION_TEMPLATE
1710 template<
size_t _Np,
typename... _Types>
1711 constexpr variant_alternative_t<_Np, variant<_Types...>>&
1712 get(variant<_Types...>& __v)
1714 static_assert(_Np <
sizeof...(_Types),
1715 "The index must be in [0, number of alternatives)");
1716 if (__v.index() != _Np)
1717 __throw_bad_variant_access(__v.valueless_by_exception());
1718 return __detail::__variant::__get<_Np>(__v);
1721 template<
size_t _Np,
typename... _Types>
1722 constexpr variant_alternative_t<_Np, variant<_Types...>>&&
1723 get(variant<_Types...>&& __v)
1725 static_assert(_Np <
sizeof...(_Types),
1726 "The index must be in [0, number of alternatives)");
1727 if (__v.index() != _Np)
1728 __throw_bad_variant_access(__v.valueless_by_exception());
1729 return __detail::__variant::__get<_Np>(
std::move(__v));
1732 template<
size_t _Np,
typename... _Types>
1733 constexpr const variant_alternative_t<_Np, variant<_Types...>>&
1734 get(
const variant<_Types...>& __v)
1736 static_assert(_Np <
sizeof...(_Types),
1737 "The index must be in [0, number of alternatives)");
1738 if (__v.index() != _Np)
1739 __throw_bad_variant_access(__v.valueless_by_exception());
1740 return __detail::__variant::__get<_Np>(__v);
1743 template<
size_t _Np,
typename... _Types>
1744 constexpr const variant_alternative_t<_Np, variant<_Types...>>&&
1745 get(
const variant<_Types...>&& __v)
1747 static_assert(_Np <
sizeof...(_Types),
1748 "The index must be in [0, number of alternatives)");
1749 if (__v.index() != _Np)
1750 __throw_bad_variant_access(__v.valueless_by_exception());
1751 return __detail::__variant::__get<_Np>(
std::move(__v));
1755 template<
typename _Result_type,
typename _Visitor,
typename... _Variants>
1756 constexpr decltype(
auto)
1757 __do_visit(_Visitor&& __visitor, _Variants&&... __variants)
1760 if constexpr (
sizeof...(_Variants) == 0)
1762 if constexpr (is_void_v<_Result_type>)
1763 return (
void) std::forward<_Visitor>(__visitor)();
1765 return std::forward<_Visitor>(__visitor)();
1769 constexpr size_t __max = 11;
1772 using _V0 =
typename _Nth_type<0, _Variants...>::type;
1774 constexpr auto __n = variant_size_v<remove_reference_t<_V0>>;
1776 if constexpr (
sizeof...(_Variants) > 1 || __n > __max)
1779 constexpr auto& __vtable = __detail::__variant::__gen_vtable<
1780 _Result_type, _Visitor&&, _Variants&&...>::_S_vtable;
1782 auto __func_ptr = __vtable._M_access(__variants.index()...);
1783 return (*__func_ptr)(std::forward<_Visitor>(__visitor),
1784 std::forward<_Variants>(__variants)...);
1790 = [](_V0& __v, ...) -> _V0& {
return __v; }(__variants...);
1792 using __detail::__variant::_Multi_array;
1793 using __detail::__variant::__gen_vtable_impl;
1794 using _Ma = _Multi_array<_Result_type (*)(_Visitor&&, _V0&&)>;
1796#ifdef _GLIBCXX_DEBUG
1797# define _GLIBCXX_VISIT_UNREACHABLE __builtin_trap
1799# define _GLIBCXX_VISIT_UNREACHABLE __builtin_unreachable
1802#define _GLIBCXX_VISIT_CASE(N) \
1805 if constexpr (N < __n) \
1807 return __gen_vtable_impl<_Ma, index_sequence<N>>:: \
1808 __visit_invoke(std::forward<_Visitor>(__visitor), \
1809 std::forward<_V0>(__v0)); \
1811 else _GLIBCXX_VISIT_UNREACHABLE(); \
1814 switch (__v0.index())
1816 _GLIBCXX_VISIT_CASE(0)
1817 _GLIBCXX_VISIT_CASE(1)
1818 _GLIBCXX_VISIT_CASE(2)
1819 _GLIBCXX_VISIT_CASE(3)
1820 _GLIBCXX_VISIT_CASE(4)
1821 _GLIBCXX_VISIT_CASE(5)
1822 _GLIBCXX_VISIT_CASE(6)
1823 _GLIBCXX_VISIT_CASE(7)
1824 _GLIBCXX_VISIT_CASE(8)
1825 _GLIBCXX_VISIT_CASE(9)
1826 _GLIBCXX_VISIT_CASE(10)
1828 using __detail::__variant::__variant_idx_cookie;
1829 using __detail::__variant::__variant_cookie;
1830 if constexpr (is_same_v<_Result_type, __variant_idx_cookie>
1831 || is_same_v<_Result_type, __variant_cookie>)
1833 using _Npos = index_sequence<variant_npos>;
1834 return __gen_vtable_impl<_Ma, _Npos>::
1835 __visit_invoke(std::forward<_Visitor>(__visitor),
1836 std::forward<_V0>(__v0));
1839 _GLIBCXX_VISIT_UNREACHABLE();
1841 _GLIBCXX_VISIT_UNREACHABLE();
1843#undef _GLIBCXX_VISIT_CASE
1844#undef _GLIBCXX_VISIT_UNREACHABLE
1850 template<
typename _Visitor,
typename... _Variants>
1851 constexpr __detail::__variant::__visit_result_t<_Visitor, _Variants...>
1852 visit(_Visitor&& __visitor, _Variants&&... __variants)
1854 namespace __variant = std::__detail::__variant;
1856 if ((__variant::__as(__variants).valueless_by_exception() || ...))
1857 __throw_bad_variant_access(
"std::visit: variant is valueless");
1860 = __detail::__variant::__visit_result_t<_Visitor, _Variants...>;
1862 using _Tag = __detail::__variant::__deduce_visit_result<_Result_type>;
1864 if constexpr (
sizeof...(_Variants) == 1)
1866 using _Vp =
decltype(__variant::__as(std::declval<_Variants>()...));
1868 constexpr bool __visit_rettypes_match = __detail::__variant::
1869 __check_visitor_results<_Visitor, _Vp>(
1871 if constexpr (!__visit_rettypes_match)
1873 static_assert(__visit_rettypes_match,
1874 "std::visit requires the visitor to have the same "
1875 "return type for all alternatives of a variant");
1879 return std::__do_visit<_Tag>(
1880 std::forward<_Visitor>(__visitor),
1881 static_cast<_Vp
>(__variants)...);
1884 return std::__do_visit<_Tag>(
1885 std::forward<_Visitor>(__visitor),
1886 __variant::__as(std::forward<_Variants>(__variants))...);
1889#if __cplusplus > 201703L
1890 template<
typename _Res,
typename _Visitor,
typename... _Variants>
1892 visit(_Visitor&& __visitor, _Variants&&... __variants)
1894 namespace __variant = std::__detail::__variant;
1896 if ((__variant::__as(__variants).valueless_by_exception() || ...))
1897 __throw_bad_variant_access(
"std::visit<R>: variant is valueless");
1899 return std::__do_visit<_Res>(std::forward<_Visitor>(__visitor),
1900 __variant::__as(std::forward<_Variants>(__variants))...);
1905 template<bool,
typename... _Types>
1906 struct __variant_hash_call_base_impl
1909 operator()(
const variant<_Types...>& __t)
const
1910 noexcept((is_nothrow_invocable_v<hash<decay_t<_Types>>, _Types> && ...))
1913 __detail::__variant::__raw_visit(
1914 [&__t, &__ret](
auto&& __t_mem)
mutable
1916 using _Type = __remove_cvref_t<
decltype(__t_mem)>;
1917 if constexpr (!is_same_v<_Type,
1918 __detail::__variant::__variant_cookie>)
1928 template<
typename... _Types>
1929 struct __variant_hash_call_base_impl<false, _Types...> {};
1931 template<
typename... _Types>
1932 using __variant_hash_call_base =
1933 __variant_hash_call_base_impl<(__poison_hash<remove_const_t<_Types>>::
1934 __enable_hash_call &&...), _Types...>;
1937 template<
typename... _Types>
1938 struct hash<variant<_Types...>>
1939 :
private __detail::__variant::_Variant_hash_base<
1940 variant<_Types...>, std::index_sequence_for<_Types...>>,
1941 public __variant_hash_call_base<_Types...>
1943 using result_type [[__deprecated__]] = size_t;
1944 using argument_type [[__deprecated__]] = variant<_Types...>;
1948 struct hash<monostate>
1950 using result_type [[__deprecated__]] = size_t;
1951 using argument_type [[__deprecated__]] = monostate;
1954 operator()(
const monostate&)
const noexcept
1956 constexpr size_t __magic_monostate_hash = -7777;
1957 return __magic_monostate_hash;
1961 template<
typename... _Types>
1962 struct __is_fast_hash<hash<variant<_Types...>>>
1963 : bool_constant<(__is_fast_hash<_Types>::value && ...)>
1966_GLIBCXX_END_NAMESPACE_VERSION
constexpr bool operator<=(const duration< _Rep1, _Period1 > &__lhs, const duration< _Rep2, _Period2 > &__rhs)
constexpr bool operator>=(const duration< _Rep1, _Period1 > &__lhs, const duration< _Rep2, _Period2 > &__rhs)
constexpr bool operator<(const duration< _Rep1, _Period1 > &__lhs, const duration< _Rep2, _Period2 > &__rhs)
constexpr bool operator>(const duration< _Rep1, _Period1 > &__lhs, const duration< _Rep2, _Period2 > &__rhs)
typename remove_reference< _Tp >::type remove_reference_t
Alias template for remove_reference.
__bool_constant< true > true_type
The type used as a compile-time boolean with true value.
__bool_constant< 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.
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.
void void_t
A metafunction that always yields void, used for detecting valid types.
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.