29 #ifndef _GLIBCXX_VARIANT
30 #define _GLIBCXX_VARIANT 1
32 #pragma GCC system_header
34 #if __cplusplus >= 201703L
47 #if __cplusplus == 201703L
53 namespace std _GLIBCXX_VISIBILITY(default)
55 _GLIBCXX_BEGIN_NAMESPACE_VERSION
57 #if __cplusplus >= 202002L && __cpp_concepts
59 # define __cpp_lib_variant 202106L
61 # define __cpp_lib_variant 202102L
64 template<
typename... _Types>
class tuple;
65 template<
typename... _Types>
class variant;
66 template <
typename>
struct hash;
68 template<
typename _Variant>
71 template<
typename _Variant>
72 struct variant_size<const _Variant> : variant_size<_Variant> {};
74 template<
typename _Variant>
75 struct variant_size<volatile _Variant> : variant_size<_Variant> {};
77 template<
typename _Variant>
78 struct variant_size<const volatile _Variant> : variant_size<_Variant> {};
80 template<
typename... _Types>
81 struct variant_size<variant<_Types...>>
84 template<
typename _Variant>
85 inline constexpr
size_t variant_size_v = variant_size<_Variant>::value;
87 template<
typename... _Types>
88 inline constexpr
size_t
89 variant_size_v<variant<_Types...>> =
sizeof...(_Types);
91 template<
typename... _Types>
92 inline constexpr
size_t
93 variant_size_v<
const variant<_Types...>> =
sizeof...(_Types);
95 template<
size_t _Np,
typename _Variant>
96 struct variant_alternative;
98 template<
size_t _Np,
typename... _Types>
99 struct variant_alternative<_Np, variant<_Types...>>
101 static_assert(_Np <
sizeof...(_Types));
103 using type =
typename _Nth_type<_Np, _Types...>::type;
106 template<
size_t _Np,
typename _Variant>
107 using variant_alternative_t =
108 typename variant_alternative<_Np, _Variant>::type;
110 template<
size_t _Np,
typename _Variant>
111 struct variant_alternative<_Np, const _Variant>
112 {
using type = add_const_t<variant_alternative_t<_Np, _Variant>>; };
114 template<
size_t _Np,
typename _Variant>
115 struct variant_alternative<_Np, volatile _Variant>
116 {
using type = add_volatile_t<variant_alternative_t<_Np, _Variant>>; };
118 template<
size_t _Np,
typename _Variant>
119 struct variant_alternative<_Np, const volatile _Variant>
120 {
using type = add_cv_t<variant_alternative_t<_Np, _Variant>>; };
122 inline constexpr
size_t variant_npos = -1;
124 template<
size_t _Np,
typename... _Types>
125 constexpr variant_alternative_t<_Np, variant<_Types...>>&
126 get(variant<_Types...>&);
128 template<
size_t _Np,
typename... _Types>
129 constexpr variant_alternative_t<_Np, variant<_Types...>>&&
130 get(variant<_Types...>&&);
132 template<
size_t _Np,
typename... _Types>
133 constexpr variant_alternative_t<_Np, variant<_Types...>>
const&
134 get(
const variant<_Types...>&);
136 template<
size_t _Np,
typename... _Types>
137 constexpr variant_alternative_t<_Np, variant<_Types...>>
const&&
138 get(
const variant<_Types...>&&);
140 template<
typename _Result_type,
typename _Visitor,
typename... _Variants>
141 constexpr decltype(
auto)
142 __do_visit(_Visitor&& __visitor, _Variants&&... __variants);
144 template <typename... _Types, typename _Tp>
147 __variant_cast(_Tp&& __rhs)
149 if constexpr (is_lvalue_reference_v<_Tp>)
151 if constexpr (is_const_v<remove_reference_t<_Tp>>)
152 return static_cast<const variant<_Types...>&>(__rhs);
154 return static_cast<variant<_Types...>&>(__rhs);
157 return static_cast<variant<_Types...>&&>(__rhs);
165 struct __variant_cookie {};
167 struct __variant_idx_cookie {
using type = __variant_idx_cookie; };
169 template<
typename _Tp>
struct __deduce_visit_result {
using type = _Tp; };
172 template<
typename _Visitor,
typename... _Variants>
174 __raw_visit(_Visitor&& __visitor, _Variants&&... __variants)
176 std::__do_visit<__variant_cookie>(std::forward<_Visitor>(__visitor),
177 std::forward<_Variants>(__variants)...);
181 template<
typename _Visitor,
typename... _Variants>
183 __raw_idx_visit(_Visitor&& __visitor, _Variants&&... __variants)
185 std::__do_visit<__variant_idx_cookie>(std::forward<_Visitor>(__visitor),
186 std::forward<_Variants>(__variants)...);
191 template<
typename... _Types>
192 constexpr std::variant<_Types...>&
193 __as(std::variant<_Types...>& __v) noexcept
196 template<
typename... _Types>
197 constexpr
const std::variant<_Types...>&
198 __as(
const std::variant<_Types...>& __v) noexcept
201 template<
typename... _Types>
202 constexpr std::variant<_Types...>&&
203 __as(std::variant<_Types...>&& __v) noexcept
206 template<
typename... _Types>
207 constexpr
const std::variant<_Types...>&&
208 __as(
const std::variant<_Types...>&& __v) noexcept
217 template<
typename _Type,
bool = std::is_trivially_destructible_v<_Type>>
218 struct _Uninitialized;
220 template<
typename _Type>
221 struct _Uninitialized<_Type, true>
223 template<
typename... _Args>
225 _Uninitialized(in_place_index_t<0>, _Args&&... __args)
229 constexpr
const _Type& _M_get() const & noexcept
230 {
return _M_storage; }
232 constexpr _Type& _M_get() & noexcept
233 {
return _M_storage; }
235 constexpr
const _Type&& _M_get() const && noexcept
238 constexpr _Type&& _M_get() && noexcept
244 template<
typename _Type>
245 struct _Uninitialized<_Type, false>
247 #if __cpp_lib_variant >= 202106L
248 template<
typename... _Args>
250 _Uninitialized(in_place_index_t<0>, _Args&&... __args)
254 constexpr ~_Uninitialized() { }
256 _Uninitialized(
const _Uninitialized&) =
default;
257 _Uninitialized(_Uninitialized&&) =
default;
258 _Uninitialized& operator=(
const _Uninitialized&) =
default;
259 _Uninitialized& operator=(_Uninitialized&&) =
default;
261 constexpr
const _Type& _M_get() const & noexcept
262 {
return _M_storage; }
264 constexpr _Type& _M_get() & noexcept
265 {
return _M_storage; }
267 constexpr
const _Type&& _M_get() const && noexcept
270 constexpr _Type&& _M_get() && noexcept
273 struct _Empty_byte { };
276 _Empty_byte _M_empty;
280 template<
typename... _Args>
282 _Uninitialized(in_place_index_t<0>, _Args&&... __args)
285 _Type(std::forward<_Args>(__args)...);
288 const _Type& _M_get() const & noexcept
289 {
return *_M_storage._M_ptr(); }
291 _Type& _M_get() & noexcept
292 {
return *_M_storage._M_ptr(); }
294 const _Type&& _M_get() const && noexcept
295 {
return std::move(*_M_storage._M_ptr()); }
297 _Type&& _M_get() && noexcept
298 {
return std::move(*_M_storage._M_ptr()); }
300 __gnu_cxx::__aligned_membuf<_Type> _M_storage;
304 template<
size_t _Np,
typename _Union>
305 constexpr decltype(
auto)
306 __get_n(_Union&& __u) noexcept
308 if constexpr (_Np == 0)
309 return
std::
forward<_Union>(__u)._M_first._M_get();
310 else if constexpr (_Np == 1)
311 return
std::
forward<_Union>(__u)._M_rest._M_first._M_get();
312 else if constexpr (_Np == 2)
313 return
std::
forward<_Union>(__u)._M_rest._M_rest._M_first._M_get();
315 return __variant::__get_n<_Np - 3>(
316 std::
forward<_Union>(__u)._M_rest._M_rest._M_rest);
320 template<
size_t _Np, typename _Variant>
321 constexpr decltype(auto)
322 __get(_Variant&& __v) noexcept
323 {
return __variant::__get_n<_Np>(std::forward<_Variant>(__v)._M_u); }
325 template<
typename... _Types>
328 static constexpr
bool _S_default_ctor =
329 is_default_constructible_v<
typename _Nth_type<0, _Types...>::type>;
330 static constexpr
bool _S_copy_ctor =
331 (is_copy_constructible_v<_Types> && ...);
332 static constexpr
bool _S_move_ctor =
333 (is_move_constructible_v<_Types> && ...);
334 static constexpr
bool _S_copy_assign =
336 && (is_copy_assignable_v<_Types> && ...);
337 static constexpr
bool _S_move_assign =
339 && (is_move_assignable_v<_Types> && ...);
341 static constexpr
bool _S_trivial_dtor =
342 (is_trivially_destructible_v<_Types> && ...);
343 static constexpr
bool _S_trivial_copy_ctor =
344 (is_trivially_copy_constructible_v<_Types> && ...);
345 static constexpr
bool _S_trivial_move_ctor =
346 (is_trivially_move_constructible_v<_Types> && ...);
347 static constexpr
bool _S_trivial_copy_assign =
348 _S_trivial_dtor && _S_trivial_copy_ctor
349 && (is_trivially_copy_assignable_v<_Types> && ...);
350 static constexpr
bool _S_trivial_move_assign =
351 _S_trivial_dtor && _S_trivial_move_ctor
352 && (is_trivially_move_assignable_v<_Types> && ...);
356 static constexpr
bool _S_nothrow_default_ctor =
357 is_nothrow_default_constructible_v<
358 typename _Nth_type<0, _Types...>::type>;
359 static constexpr
bool _S_nothrow_copy_ctor =
false;
360 static constexpr
bool _S_nothrow_move_ctor =
361 (is_nothrow_move_constructible_v<_Types> && ...);
362 static constexpr
bool _S_nothrow_copy_assign =
false;
363 static constexpr
bool _S_nothrow_move_assign =
365 && (is_nothrow_move_assignable_v<_Types> && ...);
369 template<
typename... _Types>
370 union _Variadic_union
372 _Variadic_union() =
default;
374 template<
size_t _Np,
typename... _Args>
375 _Variadic_union(in_place_index_t<_Np>, _Args&&...) =
delete;
378 template<
typename _First,
typename... _Rest>
379 union _Variadic_union<_First, _Rest...>
381 constexpr _Variadic_union() : _M_rest() { }
383 template<
typename... _Args>
385 _Variadic_union(in_place_index_t<0>, _Args&&... __args)
386 : _M_first(in_place_index<0>,
std::
forward<_Args>(__args)...)
389 template<
size_t _Np,
typename... _Args>
391 _Variadic_union(in_place_index_t<_Np>, _Args&&... __args)
392 : _M_rest(in_place_index<_Np-1>,
std::
forward<_Args>(__args)...)
395 #if __cpp_lib_variant >= 202106L
396 _Variadic_union(
const _Variadic_union&) =
default;
397 _Variadic_union(_Variadic_union&&) =
default;
398 _Variadic_union& operator=(
const _Variadic_union&) =
default;
399 _Variadic_union& operator=(_Variadic_union&&) =
default;
401 ~_Variadic_union() =
default;
403 constexpr ~_Variadic_union()
404 requires (!__has_trivial_destructor(_First))
405 || (!__has_trivial_destructor(_Variadic_union<_Rest...>))
409 _Uninitialized<_First> _M_first;
410 _Variadic_union<_Rest...> _M_rest;
418 template<
typename _Tp>
419 struct _Never_valueless_alt
420 : __and_<bool_constant<sizeof(_Tp) <= 256>, is_trivially_copyable<_Tp>>
433 template <typename... _Types>
434 constexpr bool __never_valueless()
436 return _Traits<_Types...>::_S_move_assign
437 && (_Never_valueless_alt<_Types>::value && ...);
441 template<bool __trivially_destructible, typename... _Types>
442 struct _Variant_storage;
444 template <typename... _Types>
445 using __select_index =
446 typename __select_int::_Select_int_base<sizeof...(_Types),
448 unsigned short>::type::value_type;
450 template<typename... _Types>
451 struct _Variant_storage<false, _Types...>
455 : _M_index(static_cast<__index_type>(variant_npos))
458 template<size_t _Np, typename... _Args>
460 _Variant_storage(in_place_index_t<_Np>, _Args&&... __args)
461 : _M_u(in_place_index<_Np>, std::forward<_Args>(__args)...),
468 if (!_M_valid()) [[unlikely]]
471 std::__do_visit<void>([](auto&& __this_mem) mutable
473 std::_Destroy(std::__addressof(__this_mem));
474 }, __variant_cast<_Types...>(*this));
476 _M_index = static_cast<__index_type>(variant_npos);
484 _M_valid() const noexcept
486 if constexpr (__variant::__never_valueless<_Types...>())
488 return this->_M_index != __index_type(variant_npos);
491 _Variadic_union<_Types...> _M_u;
492 using __index_type = __select_index<_Types...>;
493 __index_type _M_index;
496 template<typename... _Types>
497 struct _Variant_storage<true, _Types...>
501 : _M_index(static_cast<__index_type>(variant_npos))
504 template<
size_t _Np,
typename... _Args>
506 _Variant_storage(in_place_index_t<_Np>, _Args&&... __args)
507 : _M_u(in_place_index<_Np>,
std::
forward<_Args>(__args)...),
513 { _M_index =
static_cast<__index_type
>(variant_npos); }
516 _M_valid() const noexcept
518 if constexpr (__variant::__never_valueless<_Types...>())
526 return this->_M_index != static_cast<__index_type>(variant_npos);
529 _Variadic_union<_Types...> _M_u;
530 using __index_type = __select_index<_Types...>;
531 __index_type _M_index;
535 template<
size_t _Np,
bool _Triv, typename... _Types, typename... _Args>
538 __emplace(_Variant_storage<_Triv, _Types...>& __v, _Args&&... __args)
547 template<
typename... _Types>
548 using _Variant_storage_alias =
549 _Variant_storage<_Traits<_Types...>::_S_trivial_dtor, _Types...>;
554 template<bool,
typename... _Types>
555 struct _Copy_ctor_base : _Variant_storage_alias<_Types...>
557 using _Base = _Variant_storage_alias<_Types...>;
561 _Copy_ctor_base(
const _Copy_ctor_base& __rhs)
562 noexcept(_Traits<_Types...>::_S_nothrow_copy_ctor)
564 __variant::__raw_idx_visit(
565 [
this](
auto&& __rhs_mem,
auto __rhs_index)
mutable
567 constexpr
size_t __j = __rhs_index;
568 if constexpr (__j != variant_npos)
570 in_place_index<__j>, __rhs_mem);
571 }, __variant_cast<_Types...>(__rhs));
572 this->_M_index = __rhs._M_index;
575 _Copy_ctor_base(_Copy_ctor_base&&) =
default;
576 _Copy_ctor_base& operator=(
const _Copy_ctor_base&) =
default;
577 _Copy_ctor_base& operator=(_Copy_ctor_base&&) =
default;
580 template<
typename... _Types>
581 struct _Copy_ctor_base<true, _Types...> : _Variant_storage_alias<_Types...>
583 using _Base = _Variant_storage_alias<_Types...>;
587 template<
typename... _Types>
588 using _Copy_ctor_alias =
589 _Copy_ctor_base<_Traits<_Types...>::_S_trivial_copy_ctor, _Types...>;
591 template<bool,
typename... _Types>
592 struct _Move_ctor_base : _Copy_ctor_alias<_Types...>
594 using _Base = _Copy_ctor_alias<_Types...>;
598 _Move_ctor_base(_Move_ctor_base&& __rhs)
599 noexcept(_Traits<_Types...>::_S_nothrow_move_ctor)
601 __variant::__raw_idx_visit(
602 [
this](
auto&& __rhs_mem,
auto __rhs_index)
mutable
604 constexpr
size_t __j = __rhs_index;
605 if constexpr (__j != variant_npos)
609 }, __variant_cast<_Types...>(
std::move(__rhs)));
610 this->_M_index = __rhs._M_index;
613 _Move_ctor_base(
const _Move_ctor_base&) =
default;
614 _Move_ctor_base& operator=(
const _Move_ctor_base&) =
default;
615 _Move_ctor_base& operator=(_Move_ctor_base&&) =
default;
618 template<
typename... _Types>
619 struct _Move_ctor_base<true, _Types...> : _Copy_ctor_alias<_Types...>
621 using _Base = _Copy_ctor_alias<_Types...>;
625 template<
typename... _Types>
626 using _Move_ctor_alias =
627 _Move_ctor_base<_Traits<_Types...>::_S_trivial_move_ctor, _Types...>;
629 template<bool,
typename... _Types>
630 struct _Copy_assign_base : _Move_ctor_alias<_Types...>
632 using _Base = _Move_ctor_alias<_Types...>;
637 operator=(
const _Copy_assign_base& __rhs)
638 noexcept(_Traits<_Types...>::_S_nothrow_copy_assign)
640 __variant::__raw_idx_visit(
641 [
this](
auto&& __rhs_mem,
auto __rhs_index)
mutable
643 constexpr
size_t __j = __rhs_index;
644 if constexpr (__j == variant_npos)
646 else if (this->_M_index == __j)
647 __variant::__get<__j>(*
this) = __rhs_mem;
650 using _Tj =
typename _Nth_type<__j, _Types...>::type;
651 if constexpr (is_nothrow_copy_constructible_v<_Tj>
652 || !is_nothrow_move_constructible_v<_Tj>)
653 __variant::__emplace<__j>(*
this, __rhs_mem);
656 using _Variant = variant<_Types...>;
657 _Variant& __self = __variant_cast<_Types...>(*this);
658 __self = _Variant(in_place_index<__j>, __rhs_mem);
661 }, __variant_cast<_Types...>(__rhs));
665 _Copy_assign_base(
const _Copy_assign_base&) =
default;
666 _Copy_assign_base(_Copy_assign_base&&) =
default;
667 _Copy_assign_base& operator=(_Copy_assign_base&&) =
default;
670 template<
typename... _Types>
671 struct _Copy_assign_base<true, _Types...> : _Move_ctor_alias<_Types...>
673 using _Base = _Move_ctor_alias<_Types...>;
677 template<
typename... _Types>
678 using _Copy_assign_alias =
679 _Copy_assign_base<_Traits<_Types...>::_S_trivial_copy_assign, _Types...>;
681 template<bool,
typename... _Types>
682 struct _Move_assign_base : _Copy_assign_alias<_Types...>
684 using _Base = _Copy_assign_alias<_Types...>;
689 operator=(_Move_assign_base&& __rhs)
690 noexcept(_Traits<_Types...>::_S_nothrow_move_assign)
692 __variant::__raw_idx_visit(
693 [
this](
auto&& __rhs_mem,
auto __rhs_index)
mutable
695 constexpr
size_t __j = __rhs_index;
696 if constexpr (__j != variant_npos)
698 if (this->_M_index == __j)
699 __variant::__get<__j>(*
this) =
std::move(__rhs_mem);
702 using _Tj =
typename _Nth_type<__j, _Types...>::type;
703 if constexpr (is_nothrow_move_constructible_v<_Tj>)
704 __variant::__emplace<__j>(*
this,
std::move(__rhs_mem));
707 using _Variant = variant<_Types...>;
708 _Variant& __self = __variant_cast<_Types...>(*this);
709 __self.template emplace<__j>(
std::move(__rhs_mem));
715 }, __variant_cast<_Types...>(__rhs));
719 _Move_assign_base(
const _Move_assign_base&) =
default;
720 _Move_assign_base(_Move_assign_base&&) =
default;
721 _Move_assign_base& operator=(
const _Move_assign_base&) =
default;
724 template<
typename... _Types>
725 struct _Move_assign_base<true, _Types...> : _Copy_assign_alias<_Types...>
727 using _Base = _Copy_assign_alias<_Types...>;
731 template<
typename... _Types>
732 using _Move_assign_alias =
733 _Move_assign_base<_Traits<_Types...>::_S_trivial_move_assign, _Types...>;
735 template<
typename... _Types>
736 struct _Variant_base : _Move_assign_alias<_Types...>
738 using _Base = _Move_assign_alias<_Types...>;
741 _Variant_base() noexcept(_Traits<_Types...>::_S_nothrow_default_ctor)
742 : _Variant_base(in_place_index<0>) { }
744 template<
size_t _Np,
typename... _Args>
746 _Variant_base(in_place_index_t<_Np> __i, _Args&&... __args)
750 _Variant_base(
const _Variant_base&) =
default;
751 _Variant_base(_Variant_base&&) =
default;
752 _Variant_base& operator=(
const _Variant_base&) =
default;
753 _Variant_base& operator=(_Variant_base&&) =
default;
756 template<
typename _Tp,
typename... _Types>
757 inline constexpr
bool __exactly_once
758 = std::__find_uniq_type_in_pack<_Tp, _Types...>() <
sizeof...(_Types);
761 template<
typename _Ti>
struct _Arr { _Ti _M_x[1]; };
764 template<
size_t _Ind,
typename _Tp,
typename _Ti,
typename =
void>
773 template<
size_t _Ind,
typename _Tp,
typename _Ti>
774 struct _Build_FUN<_Ind, _Tp, _Ti,
775 void_t<decltype(_Arr<_Ti>{{std::declval<_Tp>()}})>>
778 static integral_constant<size_t, _Ind> _S_fun(_Ti);
781 template<
typename _Tp,
typename _Variant,
782 typename = make_index_sequence<variant_size_v<_Variant>>>
785 template<
typename _Tp,
typename... _Ti,
size_t... _Ind>
787 : _Build_FUN<_Ind, _Tp, _Ti>...
789 using _Build_FUN<_Ind, _Tp, _Ti>::_S_fun...;
794 template<
typename _Tp,
typename _Variant>
796 = decltype(_Build_FUNs<_Tp, _Variant>::_S_fun(std::declval<_Tp>()));
799 template<
typename _Tp,
typename _Variant,
typename =
void>
800 struct __accepted_index
801 : integral_constant<size_t, variant_npos>
804 template<
typename _Tp,
typename _Variant>
805 struct __accepted_index<_Tp, _Variant,
void_t<_FUN_type<_Tp, _Variant>>>
806 : _FUN_type<_Tp, _Variant>
809 template <
typename _Maybe_variant_cookie,
typename _Variant>
810 struct _Extra_visit_slot_needed
812 template <
typename>
struct _Variant_never_valueless;
814 template <
typename... _Types>
815 struct _Variant_never_valueless<variant<_Types...>>
816 :
bool_constant<__variant::__never_valueless<_Types...>()> {};
818 static constexpr
bool value =
819 (is_same_v<_Maybe_variant_cookie, __variant_cookie>
820 || is_same_v<_Maybe_variant_cookie, __variant_idx_cookie>)
821 && !_Variant_never_valueless<__remove_cvref_t<_Variant>>::value;
825 template<
typename _Tp,
size_t... _Dimensions>
829 template<
typename _Tp>
830 struct _Multi_array<_Tp>
833 struct __untag_result
835 {
using element_type = _Tp; };
837 template <
typename... _Args>
838 struct __untag_result<const void(*)(_Args...)>
840 {
using element_type = void(*)(_Args...); };
842 template <
typename... _Args>
843 struct __untag_result<__variant_cookie(*)(_Args...)>
845 {
using element_type = void(*)(_Args...); };
847 template <
typename... _Args>
848 struct __untag_result<__variant_idx_cookie(*)(_Args...)>
850 {
using element_type = void(*)(_Args...); };
852 template <
typename _Res,
typename... _Args>
853 struct __untag_result<__deduce_visit_result<_Res>(*)(_Args...)>
855 {
using element_type = _Res(*)(_Args...); };
857 using __result_is_deduced = __untag_result<_Tp>;
859 constexpr
const typename __untag_result<_Tp>::element_type&
863 typename __untag_result<_Tp>::element_type _M_data;
867 template<
typename _Ret,
869 typename... _Variants,
870 size_t __first,
size_t... __rest>
871 struct _Multi_array<_Ret(*)(_Visitor, _Variants...), __first, __rest...>
873 static constexpr
size_t __index =
874 sizeof...(_Variants) -
sizeof...(__rest) - 1;
876 using _Variant =
typename _Nth_type<__index, _Variants...>::type;
878 static constexpr
int __do_cookie =
879 _Extra_visit_slot_needed<_Ret, _Variant>::value ? 1 : 0;
881 using _Tp = _Ret(*)(_Visitor, _Variants...);
883 template<
typename... _Args>
884 constexpr decltype(
auto)
885 _M_access(
size_t __first_index, _Args... __rest_indices)
const
887 return _M_arr[__first_index + __do_cookie]
888 ._M_access(__rest_indices...);
891 _Multi_array<_Tp, __rest...> _M_arr[__first + __do_cookie];
921 template<
typename _Array_type,
typename _Index_seq>
922 struct __gen_vtable_impl;
931 template<
typename _Result_type,
typename _Visitor,
size_t... __dimensions,
932 typename... _Variants,
size_t... __indices>
933 struct __gen_vtable_impl<
934 _Multi_array<_Result_type (*)(_Visitor, _Variants...), __dimensions...>,
939 _Variants...>::type>;
941 _Multi_array<_Result_type (*)(_Visitor, _Variants...),
944 static constexpr _Array_type
947 _Array_type __vtable{};
953 template<
size_t... __var_indices>
954 static constexpr
void
955 _S_apply_all_alts(_Array_type& __vtable,
958 if constexpr (_Extra_visit_slot_needed<_Result_type, _Next>::value)
959 (_S_apply_single_alt<true, __var_indices>(
960 __vtable._M_arr[__var_indices + 1],
961 &(__vtable._M_arr[0])), ...);
963 (_S_apply_single_alt<false, __var_indices>(
964 __vtable._M_arr[__var_indices]), ...);
967 template<
bool __do_cookie,
size_t __index,
typename _Tp>
968 static constexpr
void
969 _S_apply_single_alt(_Tp& __element, _Tp* __cookie_element =
nullptr)
971 if constexpr (__do_cookie)
973 __element = __gen_vtable_impl<
976 *__cookie_element = __gen_vtable_impl<
982 auto __tmp_element = __gen_vtable_impl<
985 static_assert(is_same_v<_Tp, decltype(__tmp_element)>,
986 "std::visit requires the visitor to have the same "
987 "return type for all alternatives of a variant");
988 __element = __tmp_element;
996 template<
typename _Result_type,
typename _Visitor,
typename... _Variants,
998 struct __gen_vtable_impl<
999 _Multi_array<_Result_type (*)(_Visitor, _Variants...)>,
1003 _Multi_array<_Result_type (*)(_Visitor, _Variants...)>;
1005 template<
size_t __index,
typename _Variant>
1006 static constexpr decltype(
auto)
1007 __element_by_index_or_cookie(_Variant&& __var) noexcept
1009 if constexpr (__index != variant_npos)
1010 return __variant::__get<__index>(std::forward<_Variant>(__var));
1012 return __variant_cookie{};
1015 static constexpr decltype(
auto)
1016 __visit_invoke(_Visitor&& __visitor, _Variants... __vars)
1018 if constexpr (is_same_v<_Result_type, __variant_idx_cookie>)
1022 __element_by_index_or_cookie<__indices>(
1023 std::forward<_Variants>(__vars))...,
1024 integral_constant<size_t, __indices>()...);
1025 else if constexpr (is_same_v<_Result_type, __variant_cookie>)
1028 __element_by_index_or_cookie<__indices>(
1029 std::forward<_Variants>(__vars))...);
1030 else if constexpr (_Array_type::__result_is_deduced::value)
1033 __element_by_index_or_cookie<__indices>(
1034 std::forward<_Variants>(__vars))...);
1036 return std::__invoke_r<_Result_type>(
1037 std::forward<_Visitor>(__visitor),
1038 __variant::__get<__indices>(std::forward<_Variants>(__vars))...);
1041 static constexpr
auto
1044 if constexpr (_Array_type::__result_is_deduced::value)
1046 constexpr
bool __visit_ret_type_mismatch =
1047 !is_same_v<
typename _Result_type::type,
1048 decltype(__visit_invoke(std::declval<_Visitor>(),
1049 std::declval<_Variants>()...))>;
1050 if constexpr (__visit_ret_type_mismatch)
1052 struct __cannot_match {};
1053 return __cannot_match{};
1056 return _Array_type{&__visit_invoke};
1059 return _Array_type{&__visit_invoke};
1063 template<
typename _Result_type,
typename _Visitor,
typename... _Variants>
1067 _Multi_array<_Result_type (*)(_Visitor, _Variants...),
1068 variant_size_v<remove_reference_t<_Variants>>...>;
1070 static constexpr _Array_type _S_vtable
1071 = __gen_vtable_impl<_Array_type, std::index_sequence<>>::_S_apply();
1074 template<
size_t _Np,
typename _Tp>
1075 struct _Base_dedup :
public _Tp { };
1077 template<
typename _Variant,
typename __indices>
1078 struct _Variant_hash_base;
1080 template<
typename... _Types,
size_t... __indices>
1081 struct _Variant_hash_base<variant<_Types...>,
1083 : _Base_dedup<__indices, __poison_hash<remove_const_t<_Types>>>... { };
1086 template<
size_t _Np,
typename _Variant,
1087 typename _AsV = decltype(__variant::__as(std::declval<_Variant>())),
1088 typename _Tp = variant_alternative_t<_Np, remove_reference_t<_AsV>>>
1090 = __conditional_t<is_lvalue_reference_v<_Variant>, _Tp&, _Tp&&>;
1093 template<
typename _Visitor,
typename... _Variants>
1094 using __visit_result_t
1095 = invoke_result_t<_Visitor, __get_t<0, _Variants>...>;
1097 template<
typename _Tp,
typename... _Types>
1098 constexpr
inline bool __same_types = (is_same_v<_Tp, _Types> && ...);
1100 template <
typename _Visitor,
typename _Variant,
size_t... _Idxs>
1103 return __same_types<
1104 invoke_result_t<_Visitor, __get_t<_Idxs, _Variant>>...
1111 template<
typename _Tp,
typename... _Types>
1113 holds_alternative(
const variant<_Types...>& __v) noexcept
1115 static_assert(__detail::__variant::__exactly_once<_Tp, _Types...>,
1116 "T must occur exactly once in alternatives");
1117 return __v.index() == std::__find_uniq_type_in_pack<_Tp, _Types...>();
1120 template<
typename _Tp,
typename... _Types>
1122 get(variant<_Types...>& __v)
1124 static_assert(__detail::__variant::__exactly_once<_Tp, _Types...>,
1125 "T must occur exactly once in alternatives");
1126 static_assert(!is_void_v<_Tp>,
"_Tp must not be void");
1127 constexpr
size_t __n = std::__find_uniq_type_in_pack<_Tp, _Types...>();
1128 return std::get<__n>(__v);
1131 template<
typename _Tp,
typename... _Types>
1133 get(variant<_Types...>&& __v)
1135 static_assert(__detail::__variant::__exactly_once<_Tp, _Types...>,
1136 "T must occur exactly once in alternatives");
1137 static_assert(!is_void_v<_Tp>,
"_Tp must not be void");
1138 constexpr
size_t __n = std::__find_uniq_type_in_pack<_Tp, _Types...>();
1142 template<
typename _Tp,
typename... _Types>
1143 constexpr
const _Tp&
1144 get(
const variant<_Types...>& __v)
1146 static_assert(__detail::__variant::__exactly_once<_Tp, _Types...>,
1147 "T must occur exactly once in alternatives");
1148 static_assert(!is_void_v<_Tp>,
"_Tp must not be void");
1149 constexpr
size_t __n = std::__find_uniq_type_in_pack<_Tp, _Types...>();
1150 return std::get<__n>(__v);
1153 template<
typename _Tp,
typename... _Types>
1154 constexpr
const _Tp&&
1155 get(
const variant<_Types...>&& __v)
1157 static_assert(__detail::__variant::__exactly_once<_Tp, _Types...>,
1158 "T must occur exactly once in alternatives");
1159 static_assert(!is_void_v<_Tp>,
"_Tp must not be void");
1160 constexpr
size_t __n = std::__find_uniq_type_in_pack<_Tp, _Types...>();
1164 template<
size_t _Np,
typename... _Types>
1165 constexpr
add_pointer_t<variant_alternative_t<_Np, variant<_Types...>>>
1166 get_if(variant<_Types...>* __ptr) noexcept
1168 using _Alternative_type = variant_alternative_t<_Np, variant<_Types...>>;
1169 static_assert(_Np <
sizeof...(_Types),
1170 "The index must be in [0, number of alternatives)");
1171 static_assert(!is_void_v<_Alternative_type>,
"_Tp must not be void");
1172 if (__ptr && __ptr->index() == _Np)
1177 template<
size_t _Np,
typename... _Types>
1179 add_pointer_t<
const variant_alternative_t<_Np, variant<_Types...>>>
1180 get_if(
const variant<_Types...>* __ptr) noexcept
1182 using _Alternative_type = variant_alternative_t<_Np, variant<_Types...>>;
1183 static_assert(_Np <
sizeof...(_Types),
1184 "The index must be in [0, number of alternatives)");
1185 static_assert(!is_void_v<_Alternative_type>,
"_Tp must not be void");
1186 if (__ptr && __ptr->index() == _Np)
1191 template<
typename _Tp,
typename... _Types>
1192 constexpr add_pointer_t<_Tp>
1193 get_if(variant<_Types...>* __ptr) noexcept
1195 static_assert(__detail::__variant::__exactly_once<_Tp, _Types...>,
1196 "T must occur exactly once in alternatives");
1197 static_assert(!is_void_v<_Tp>,
"_Tp must not be void");
1198 constexpr
size_t __n = std::__find_uniq_type_in_pack<_Tp, _Types...>();
1199 return std::get_if<__n>(__ptr);
1202 template<
typename _Tp,
typename... _Types>
1203 constexpr add_pointer_t<const _Tp>
1204 get_if(
const variant<_Types...>* __ptr) noexcept
1206 static_assert(__detail::__variant::__exactly_once<_Tp, _Types...>,
1207 "T must occur exactly once in alternatives");
1208 static_assert(!is_void_v<_Tp>,
"_Tp must not be void");
1209 constexpr
size_t __n = std::__find_uniq_type_in_pack<_Tp, _Types...>();
1210 return std::get_if<__n>(__ptr);
1213 struct monostate { };
1215 #define _VARIANT_RELATION_FUNCTION_TEMPLATE(__OP, __NAME) \
1216 template<typename... _Types> \
1217 constexpr bool operator __OP(const variant<_Types...>& __lhs, \
1218 const variant<_Types...>& __rhs) \
1220 bool __ret = true; \
1221 __detail::__variant::__raw_idx_visit( \
1222 [&__ret, &__lhs] (auto&& __rhs_mem, auto __rhs_index) mutable \
1224 if constexpr (__rhs_index != variant_npos) \
1226 if (__lhs.index() == __rhs_index) \
1228 auto& __this_mem = std::get<__rhs_index>(__lhs); \
1229 __ret = __this_mem __OP __rhs_mem; \
1232 __ret = (__lhs.index() + 1) __OP (__rhs_index + 1); \
1235 __ret = (__lhs.index() + 1) __OP (__rhs_index + 1); \
1240 _VARIANT_RELATION_FUNCTION_TEMPLATE(<, less)
1241 _VARIANT_RELATION_FUNCTION_TEMPLATE(<=, less_equal)
1242 _VARIANT_RELATION_FUNCTION_TEMPLATE(==, equal)
1243 _VARIANT_RELATION_FUNCTION_TEMPLATE(!=, not_equal)
1244 _VARIANT_RELATION_FUNCTION_TEMPLATE(>=, greater_equal)
1245 _VARIANT_RELATION_FUNCTION_TEMPLATE(>, greater)
1247 #undef _VARIANT_RELATION_FUNCTION_TEMPLATE
1249 constexpr
bool operator==(monostate, monostate) noexcept {
return true; }
1251 #ifdef __cpp_lib_three_way_comparison
1252 template<
typename... _Types>
1253 requires (three_way_comparable<_Types> && ...)
1256 operator<=>(const variant<_Types...>& __v, const variant<_Types...>& __w)
1258 common_comparison_category_t<compare_three_way_result_t<_Types>...> __ret
1259 = strong_ordering::equal;
1261 __detail::__variant::__raw_idx_visit(
1262 [&__ret, &__v] (
auto&& __w_mem,
auto __w_index)
mutable
1264 if constexpr (__w_index != variant_npos)
1266 if (__v.index() == __w_index)
1268 auto& __this_mem = std::get<__w_index>(__v);
1269 __ret = __this_mem <=> __w_mem;
1273 __ret = (__v.index() + 1) <=> (__w_index + 1);
1278 constexpr strong_ordering
1279 operator<=>(monostate, monostate) noexcept {
return strong_ordering::equal; }
1281 constexpr
bool operator!=(monostate, monostate) noexcept {
return false; }
1282 constexpr
bool operator<(monostate, monostate) noexcept {
return false; }
1283 constexpr
bool operator>(monostate, monostate) noexcept {
return false; }
1284 constexpr
bool operator<=(monostate, monostate) noexcept {
return true; }
1285 constexpr
bool operator>=(monostate, monostate) noexcept {
return true; }
1288 template<
typename _Visitor,
typename... _Variants>
1289 constexpr __detail::__variant::__visit_result_t<_Visitor, _Variants...>
1290 visit(_Visitor&&, _Variants&&...);
1292 template<
typename... _Types>
1293 _GLIBCXX20_CONSTEXPR
1294 inline enable_if_t<(is_move_constructible_v<_Types> && ...)
1295 && (is_swappable_v<_Types> && ...)>
1296 swap(variant<_Types...>& __lhs, variant<_Types...>& __rhs)
1297 noexcept(noexcept(__lhs.swap(__rhs)))
1298 { __lhs.swap(__rhs); }
1300 template<
typename... _Types>
1301 enable_if_t<!((is_move_constructible_v<_Types> && ...)
1302 && (is_swappable_v<_Types> && ...))>
1303 swap(variant<_Types...>&, variant<_Types...>&) =
delete;
1305 class bad_variant_access :
public exception
1308 bad_variant_access() noexcept { }
1310 const char* what() const noexcept
override
1311 {
return _M_reason; }
1314 bad_variant_access(
const char* __reason) noexcept : _M_reason(__reason) { }
1317 const char* _M_reason =
"bad variant access";
1319 friend void __throw_bad_variant_access(
const char* __what);
1324 __throw_bad_variant_access(
const char* __what)
1325 { _GLIBCXX_THROW_OR_ABORT(bad_variant_access(__what)); }
1328 __throw_bad_variant_access(
bool __valueless)
1330 if (__valueless) [[__unlikely__]]
1331 __throw_bad_variant_access(
"std::get: variant is valueless");
1333 __throw_bad_variant_access(
"std::get: wrong index for variant");
1336 template<
typename... _Types>
1338 :
private __detail::__variant::_Variant_base<_Types...>,
1339 private _Enable_default_constructor<
1340 __detail::__variant::_Traits<_Types...>::_S_default_ctor,
1341 variant<_Types...>>,
1342 private _Enable_copy_move<
1343 __detail::__variant::_Traits<_Types...>::_S_copy_ctor,
1344 __detail::__variant::_Traits<_Types...>::_S_copy_assign,
1345 __detail::__variant::_Traits<_Types...>::_S_move_ctor,
1346 __detail::__variant::_Traits<_Types...>::_S_move_assign,
1350 template <
typename... _UTypes,
typename _Tp>
1351 friend _GLIBCXX20_CONSTEXPR decltype(
auto)
1352 __variant_cast(_Tp&&);
1354 static_assert(sizeof...(_Types) > 0,
1355 "variant must have at least one alternative");
1356 static_assert(!(
std::is_reference_v<_Types> || ...),
1357 "variant must have no reference alternative");
1358 static_assert(!(
std::is_void_v<_Types> || ...),
1359 "variant must have no
void alternative");
1361 using _Base = __detail::__variant::_Variant_base<_Types...>;
1362 using _Default_ctor_enabler =
1363 _Enable_default_constructor<
1364 __detail::__variant::_Traits<_Types...>::_S_default_ctor,
1365 variant<_Types...>>;
1367 template<typename _Tp>
1368 static constexpr
bool __not_self
1369 = !is_same_v<__remove_cvref_t<_Tp>, variant>;
1371 template<typename _Tp>
1372 static constexpr
bool
1373 __exactly_once = __detail::__variant::__exactly_once<_Tp, _Types...>;
1375 template<typename _Tp>
1376 static constexpr
size_t __accepted_index
1377 = __detail::__variant::__accepted_index<_Tp, variant>::value;
1379 template<
size_t _Np, typename =
enable_if_t<(_Np < sizeof...(_Types))>>
1380 using __to_type = typename _Nth_type<_Np, _Types...>::type;
1382 template<typename _Tp, typename =
enable_if_t<__not_self<_Tp>>>
1383 using __accepted_type = __to_type<__accepted_index<_Tp>>;
1385 template<typename _Tp>
1386 static constexpr
size_t __index_of
1387 =
std::__find_uniq_type_in_pack<_Tp, _Types...>();
1389 using _Traits = __detail::__variant::_Traits<_Types...>;
1391 template<typename _Tp>
1393 template<
typename _Tp>
1394 struct __is_in_place_tag<in_place_type_t<_Tp>> :
true_type { };
1395 template<
size_t _Np>
1396 struct __is_in_place_tag<in_place_index_t<_Np>> :
true_type { };
1398 template<
typename _Tp>
1399 static constexpr
bool __not_in_place_tag
1400 = !__is_in_place_tag<__remove_cvref_t<_Tp>>::value;
1403 variant() =
default;
1404 variant(
const variant& __rhs) =
default;
1405 variant(variant&&) =
default;
1406 variant& operator=(
const variant&) =
default;
1407 variant& operator=(variant&&) =
default;
1408 _GLIBCXX20_CONSTEXPR ~variant() =
default;
1410 template<
typename _Tp,
1413 typename _Tj = __accepted_type<_Tp&&>,
1415 && is_constructible_v<_Tj, _Tp>>>
1418 noexcept(is_nothrow_constructible_v<_Tj, _Tp>)
1419 : variant(in_place_index<__accepted_index<_Tp>>,
1423 template<
typename _Tp,
typename... _Args,
1424 typename = enable_if_t<__exactly_once<_Tp>
1425 && is_constructible_v<_Tp, _Args...>>>
1427 variant(in_place_type_t<_Tp>, _Args&&... __args)
1428 : variant(in_place_index<__index_of<_Tp>>,
1432 template<
typename _Tp,
typename _Up,
typename... _Args,
1433 typename = enable_if_t<__exactly_once<_Tp>
1434 && is_constructible_v<_Tp,
1435 initializer_list<_Up>&, _Args...>>>
1437 variant(in_place_type_t<_Tp>, initializer_list<_Up> __il,
1439 : variant(in_place_index<__index_of<_Tp>>, __il,
1443 template<
size_t _Np,
typename... _Args,
1444 typename _Tp = __to_type<_Np>,
1445 typename =
enable_if_t<is_constructible_v<_Tp, _Args...>>>
1447 variant(in_place_index_t<_Np>, _Args&&... __args)
1448 : _Base(in_place_index<_Np>,
std::
forward<_Args>(__args)...),
1449 _Default_ctor_enabler(_Enable_default_constructor_tag{})
1452 template<
size_t _Np,
typename _Up,
typename... _Args,
1453 typename _Tp = __to_type<_Np>,
1455 initializer_list<_Up>&,
1458 variant(in_place_index_t<_Np>, initializer_list<_Up> __il,
1460 : _Base(in_place_index<_Np>, __il,
std::
forward<_Args>(__args)...),
1461 _Default_ctor_enabler(_Enable_default_constructor_tag{})
1464 template<
typename _Tp>
1465 _GLIBCXX20_CONSTEXPR
1466 enable_if_t<__exactly_once<__accepted_type<_Tp&&>>
1467 && is_constructible_v<__accepted_type<_Tp&&>, _Tp>
1468 && is_assignable_v<__accepted_type<_Tp&&>&, _Tp>,
1470 operator=(_Tp&& __rhs)
1471 noexcept(is_nothrow_assignable_v<__accepted_type<_Tp&&>&, _Tp>
1472 && is_nothrow_constructible_v<__accepted_type<_Tp&&>, _Tp>)
1474 constexpr
auto __index = __accepted_index<_Tp>;
1475 if (index() == __index)
1476 std::get<__index>(*
this) = std::forward<_Tp>(__rhs);
1479 using _Tj = __accepted_type<_Tp&&>;
1480 if constexpr (is_nothrow_constructible_v<_Tj, _Tp>
1481 || !is_nothrow_move_constructible_v<_Tj>)
1482 this->emplace<__index>(std::forward<_Tp>(__rhs));
1484 operator=(variant(std::forward<_Tp>(__rhs)));
1489 template<
typename _Tp,
typename... _Args>
1490 _GLIBCXX20_CONSTEXPR
1491 enable_if_t<is_constructible_v<_Tp, _Args...> && __exactly_once<_Tp>,
1493 emplace(_Args&&... __args)
1495 constexpr
size_t __index = __index_of<_Tp>;
1496 return this->emplace<__index>(std::forward<_Args>(__args)...);
1499 template<
typename _Tp,
typename _Up,
typename... _Args>
1500 _GLIBCXX20_CONSTEXPR
1501 enable_if_t<is_constructible_v<_Tp, initializer_list<_Up>&, _Args...>
1502 && __exactly_once<_Tp>,
1504 emplace(initializer_list<_Up> __il, _Args&&... __args)
1506 constexpr
size_t __index = __index_of<_Tp>;
1507 return this->emplace<__index>(__il, std::forward<_Args>(__args)...);
1510 template<
size_t _Np,
typename... _Args>
1511 _GLIBCXX20_CONSTEXPR
1512 enable_if_t<is_constructible_v<__to_type<_Np>, _Args...>,
1514 emplace(_Args&&... __args)
1516 namespace __variant = std::__detail::__variant;
1517 using type =
typename _Nth_type<_Np, _Types...>::type;
1520 if constexpr (is_nothrow_constructible_v<type, _Args...>)
1522 __variant::__emplace<_Np>(*
this, std::forward<_Args>(__args)...);
1524 else if constexpr (is_scalar_v<type>)
1527 const type __tmp(std::forward<_Args>(__args)...);
1529 __variant::__emplace<_Np>(*
this, __tmp);
1531 else if constexpr (__variant::_Never_valueless_alt<type>()
1532 && _Traits::_S_move_assign)
1535 variant __tmp(in_place_index<_Np>,
1536 std::forward<_Args>(__args)...);
1544 __variant::__emplace<_Np>(*
this, std::forward<_Args>(__args)...);
1546 return std::get<_Np>(*
this);
1549 template<
size_t _Np,
typename _Up,
typename... _Args>
1550 _GLIBCXX20_CONSTEXPR
1551 enable_if_t<is_constructible_v<__to_type<_Np>,
1552 initializer_list<_Up>&, _Args...>,
1554 emplace(initializer_list<_Up> __il, _Args&&... __args)
1556 namespace __variant = std::__detail::__variant;
1557 using type =
typename _Nth_type<_Np, _Types...>::type;
1560 if constexpr (is_nothrow_constructible_v<type,
1561 initializer_list<_Up>&,
1564 __variant::__emplace<_Np>(*
this, __il,
1565 std::forward<_Args>(__args)...);
1567 else if constexpr (__variant::_Never_valueless_alt<type>()
1568 && _Traits::_S_move_assign)
1571 variant __tmp(in_place_index<_Np>, __il,
1572 std::forward<_Args>(__args)...);
1580 __variant::__emplace<_Np>(*
this, __il,
1581 std::forward<_Args>(__args)...);
1583 return std::get<_Np>(*
this);
1586 template<
size_t _Np,
typename... _Args>
1587 enable_if_t<!(_Np <
sizeof...(_Types))> emplace(_Args&&...) =
delete;
1589 template<
typename _Tp,
typename... _Args>
1590 enable_if_t<!__exactly_once<_Tp>> emplace(_Args&&...) =
delete;
1592 constexpr
bool valueless_by_exception() const noexcept
1593 {
return !this->_M_valid(); }
1595 constexpr
size_t index() const noexcept
1597 using __index_type =
typename _Base::__index_type;
1598 if constexpr (__detail::__variant::__never_valueless<_Types...>())
1599 return this->_M_index;
1600 else if constexpr (sizeof...(_Types) <= __index_type(-1) / 2)
1603 return
size_t(__index_type(this->_M_index + 1)) - 1;
1606 _GLIBCXX20_CONSTEXPR
1608 swap(variant& __rhs)
1609 noexcept((__is_nothrow_swappable<_Types>::value && ...)
1610 && is_nothrow_move_constructible_v<variant>)
1612 static_assert((is_move_constructible_v<_Types> && ...));
1615 if (__rhs.valueless_by_exception()) [[__unlikely__]]
1617 if (!this->valueless_by_exception()) [[__likely__]]
1622 namespace __variant = __detail::__variant;
1624 __variant::__raw_idx_visit(
1625 [
this, &__rhs](
auto&& __rhs_mem,
auto __rhs_index)
mutable
1627 constexpr
size_t __j = __rhs_index;
1628 if constexpr (__j != variant_npos)
1630 if (this->index() == __j)
1633 swap(std::get<__j>(*
this), __rhs_mem);
1639 if constexpr (_Traits::_S_trivial_move_assign)
1642 __variant::__raw_idx_visit(
1643 [&__rhs](
auto&& __this_mem,
auto __this_index)
mutable
1645 constexpr
size_t __k = __this_index;
1646 if constexpr (__k != variant_npos)
1647 __variant::__emplace<__k>(__rhs,
1651 __variant::__emplace<__j>(*
this,
std::move(__tmp));
1657 #if defined(__clang__) && __clang_major__ <= 7
1663 template<
size_t _Np,
typename _Vp>
1664 friend constexpr decltype(
auto)
1665 __detail::__variant::__get(_Vp&& __v) noexcept;
1667 #define _VARIANT_RELATION_FUNCTION_TEMPLATE(__OP) \
1668 template<typename... _Tp> \
1669 friend constexpr bool \
1670 operator __OP(const variant<_Tp...>& __lhs, \
1671 const variant<_Tp...>& __rhs);
1673 _VARIANT_RELATION_FUNCTION_TEMPLATE(<)
1674 _VARIANT_RELATION_FUNCTION_TEMPLATE(<=)
1675 _VARIANT_RELATION_FUNCTION_TEMPLATE(==)
1676 _VARIANT_RELATION_FUNCTION_TEMPLATE(!=)
1677 _VARIANT_RELATION_FUNCTION_TEMPLATE(>=)
1678 _VARIANT_RELATION_FUNCTION_TEMPLATE(>)
1680 #undef _VARIANT_RELATION_FUNCTION_TEMPLATE
1683 template<
size_t _Np,
typename... _Types>
1684 constexpr variant_alternative_t<_Np, variant<_Types...>>&
1685 get(variant<_Types...>& __v)
1687 static_assert(_Np <
sizeof...(_Types),
1688 "The index must be in [0, number of alternatives)");
1689 if (__v.index() != _Np)
1690 __throw_bad_variant_access(__v.valueless_by_exception());
1691 return __detail::__variant::__get<_Np>(__v);
1694 template<
size_t _Np,
typename... _Types>
1695 constexpr variant_alternative_t<_Np, variant<_Types...>>&&
1696 get(variant<_Types...>&& __v)
1698 static_assert(_Np <
sizeof...(_Types),
1699 "The index must be in [0, number of alternatives)");
1700 if (__v.index() != _Np)
1701 __throw_bad_variant_access(__v.valueless_by_exception());
1702 return __detail::__variant::__get<_Np>(
std::move(__v));
1705 template<
size_t _Np,
typename... _Types>
1706 constexpr
const variant_alternative_t<_Np, variant<_Types...>>&
1707 get(
const variant<_Types...>& __v)
1709 static_assert(_Np <
sizeof...(_Types),
1710 "The index must be in [0, number of alternatives)");
1711 if (__v.index() != _Np)
1712 __throw_bad_variant_access(__v.valueless_by_exception());
1713 return __detail::__variant::__get<_Np>(__v);
1716 template<
size_t _Np,
typename... _Types>
1717 constexpr
const variant_alternative_t<_Np, variant<_Types...>>&&
1718 get(
const variant<_Types...>&& __v)
1720 static_assert(_Np <
sizeof...(_Types),
1721 "The index must be in [0, number of alternatives)");
1722 if (__v.index() != _Np)
1723 __throw_bad_variant_access(__v.valueless_by_exception());
1724 return __detail::__variant::__get<_Np>(
std::move(__v));
1728 template<
typename _Result_type,
typename _Visitor,
typename... _Variants>
1729 constexpr decltype(
auto)
1730 __do_visit(_Visitor&& __visitor, _Variants&&... __variants)
1733 if constexpr (
sizeof...(_Variants) == 0)
1737 constexpr
size_t __max = 11;
1740 using _V0 =
typename _Nth_type<0, _Variants...>::type;
1742 constexpr
auto __n = variant_size_v<remove_reference_t<_V0>>;
1744 if constexpr (
sizeof...(_Variants) > 1 || __n > __max)
1747 constexpr
auto& __vtable = __detail::__variant::__gen_vtable<
1748 _Result_type, _Visitor&&, _Variants&&...>::_S_vtable;
1750 auto __func_ptr = __vtable._M_access(__variants.index()...);
1751 return (*__func_ptr)(std::forward<_Visitor>(__visitor),
1752 std::forward<_Variants>(__variants)...);
1758 = [](_V0& __v, ...) -> _V0& {
return __v; }(__variants...);
1760 using __detail::__variant::_Multi_array;
1761 using __detail::__variant::__gen_vtable_impl;
1762 using _Ma = _Multi_array<_Result_type (*)(_Visitor&&, _V0&&)>;
1764 #ifdef _GLIBCXX_DEBUG
1765 # define _GLIBCXX_VISIT_UNREACHABLE __builtin_trap
1767 # define _GLIBCXX_VISIT_UNREACHABLE __builtin_unreachable
1770 #define _GLIBCXX_VISIT_CASE(N) \
1773 if constexpr (N < __n) \
1775 return __gen_vtable_impl<_Ma, index_sequence<N>>:: \
1776 __visit_invoke(std::forward<_Visitor>(__visitor), \
1777 std::forward<_V0>(__v0)); \
1779 else _GLIBCXX_VISIT_UNREACHABLE(); \
1782 switch (__v0.index())
1784 _GLIBCXX_VISIT_CASE(0)
1785 _GLIBCXX_VISIT_CASE(1)
1786 _GLIBCXX_VISIT_CASE(2)
1787 _GLIBCXX_VISIT_CASE(3)
1788 _GLIBCXX_VISIT_CASE(4)
1789 _GLIBCXX_VISIT_CASE(5)
1790 _GLIBCXX_VISIT_CASE(6)
1791 _GLIBCXX_VISIT_CASE(7)
1792 _GLIBCXX_VISIT_CASE(8)
1793 _GLIBCXX_VISIT_CASE(9)
1794 _GLIBCXX_VISIT_CASE(10)
1796 using __detail::__variant::__variant_idx_cookie;
1797 using __detail::__variant::__variant_cookie;
1798 if constexpr (is_same_v<_Result_type, __variant_idx_cookie>
1799 || is_same_v<_Result_type, __variant_cookie>)
1801 using _Npos = index_sequence<variant_npos>;
1802 return __gen_vtable_impl<_Ma, _Npos>::
1803 __visit_invoke(std::forward<_Visitor>(__visitor),
1804 std::forward<_V0>(__v0));
1807 _GLIBCXX_VISIT_UNREACHABLE();
1809 _GLIBCXX_VISIT_UNREACHABLE();
1811 #undef _GLIBCXX_VISIT_CASE
1812 #undef _GLIBCXX_VISIT_UNREACHABLE
1818 template<
typename _Visitor,
typename... _Variants>
1819 constexpr __detail::__variant::__visit_result_t<_Visitor, _Variants...>
1820 visit(_Visitor&& __visitor, _Variants&&... __variants)
1822 namespace __variant = std::__detail::__variant;
1824 if ((__variant::__as(__variants).valueless_by_exception() || ...))
1825 __throw_bad_variant_access(
"std::visit: variant is valueless");
1828 = __detail::__variant::__visit_result_t<_Visitor, _Variants...>;
1830 using _Tag = __detail::__variant::__deduce_visit_result<_Result_type>;
1832 if constexpr (
sizeof...(_Variants) == 1)
1834 using _Vp = decltype(__variant::__as(std::declval<_Variants>()...));
1836 constexpr
bool __visit_rettypes_match = __detail::__variant::
1837 __check_visitor_results<_Visitor, _Vp>(
1839 if constexpr (!__visit_rettypes_match)
1841 static_assert(__visit_rettypes_match,
1842 "std::visit requires the visitor to have the same "
1843 "return type for all alternatives of a variant");
1847 return std::__do_visit<_Tag>(
1848 std::forward<_Visitor>(__visitor),
1849 static_cast<_Vp
>(__variants)...);
1852 return std::__do_visit<_Tag>(
1853 std::forward<_Visitor>(__visitor),
1854 __variant::__as(std::forward<_Variants>(__variants))...);
1857 #if __cplusplus > 201703L
1858 template<
typename _Res,
typename _Visitor,
typename... _Variants>
1860 visit(_Visitor&& __visitor, _Variants&&... __variants)
1862 namespace __variant = std::__detail::__variant;
1864 if ((__variant::__as(__variants).valueless_by_exception() || ...))
1865 __throw_bad_variant_access(
"std::visit<R>: variant is valueless");
1867 return std::__do_visit<_Res>(std::forward<_Visitor>(__visitor),
1868 __variant::__as(std::forward<_Variants>(__variants))...);
1873 template<bool,
typename... _Types>
1874 struct __variant_hash_call_base_impl
1877 operator()(
const variant<_Types...>& __t)
const
1878 noexcept((is_nothrow_invocable_v<hash<decay_t<_Types>>, _Types> && ...))
1881 __detail::__variant::__raw_visit(
1882 [&__t, &__ret](
auto&& __t_mem)
mutable
1884 using _Type = __remove_cvref_t<decltype(__t_mem)>;
1885 if constexpr (!is_same_v<_Type,
1886 __detail::__variant::__variant_cookie>)
1887 __ret =
std::hash<
size_t>{}(__t.index())
1896 template<
typename... _Types>
1897 struct __variant_hash_call_base_impl<false, _Types...> {};
1899 template<
typename... _Types>
1900 using __variant_hash_call_base =
1901 __variant_hash_call_base_impl<(__poison_hash<remove_const_t<_Types>>::
1902 __enable_hash_call &&...), _Types...>;
1905 template<
typename... _Types>
1906 struct hash<variant<_Types...>>
1907 :
private __detail::__variant::_Variant_hash_base<
1908 variant<_Types...>, std::index_sequence_for<_Types...>>,
1909 public __variant_hash_call_base<_Types...>
1911 using result_type [[__deprecated__]] = size_t;
1912 using argument_type [[__deprecated__]] = variant<_Types...>;
1916 struct hash<monostate>
1918 using result_type [[__deprecated__]] = size_t;
1919 using argument_type [[__deprecated__]] = monostate;
1922 operator()(
const monostate&)
const noexcept
1924 constexpr
size_t __magic_monostate_hash = -7777;
1925 return __magic_monostate_hash;
1929 template<
typename... _Types>
1930 struct __is_fast_hash<hash<variant<_Types...>>>
1934 _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 make_signed< _Tp >::type make_signed_t
Alias template for make_signed.
typename enable_if< _Cond, _Tp >::type enable_if_t
Alias template for enable_if.
constexpr _Tp * __addressof(_Tp &__r) noexcept
Same as C++11 std::addressof.
constexpr __invoke_result< _Callable, _Args... >::type __invoke(_Callable &&__fn, _Args &&... __args) noexcept(__is_nothrow_invocable< _Callable, _Args... >::value)
Invoke a callable object.
constexpr std::remove_reference< _Tp >::type && move(_Tp &&__t) noexcept
Convert a value to an rvalue.
constexpr _Tp && forward(typename std::remove_reference< _Tp >::type &__t) noexcept
Forward an lvalue.
void swap(any &__x, any &__y) noexcept
Exchange the states of two any objects.
constexpr _Tp * addressof(_Tp &__r) noexcept
Returns the actual address of the object or function referenced by r, even in the presence of an over...
ISO C++ entities toplevel namespace is std.
make_integer_sequence< size_t, _Num > make_index_sequence
Alias template make_index_sequence.
constexpr void _Construct(_Tp *__p, _Args &&... __args)
integer_sequence< size_t, _Idx... > index_sequence
Alias template index_sequence.
typename __detail::__cmp3way_res_impl< _Tp, _Up >::type compare_three_way_result_t
[cmp.result], result of three-way comparison
Primary class template hash.
Class template integer_sequence.