30 #ifndef _GLIBCXX_OPTIONAL
31 #define _GLIBCXX_OPTIONAL 1
33 #pragma GCC system_header
35 #if __cplusplus >= 201703L
46 #if __cplusplus > 201703L
50 #if __cplusplus > 202002L
54 namespace std _GLIBCXX_VISIBILITY(default)
56 _GLIBCXX_BEGIN_NAMESPACE_VERSION
63 #if __cplusplus > 202002L && __cpp_lib_concepts
64 # define __cpp_lib_optional 202110L
65 #elif __cplusplus >= 202002L
66 # define __cpp_lib_optional 202106L
68 # define __cpp_lib_optional 201606L
71 template<
typename _Tp>
82 enum class _Construct { _Token };
85 explicit constexpr
nullopt_t(_Construct) noexcept { }
91 template<
typename _Fn>
struct _Optional_func { _Fn& _M_f; };
104 const char*
what() const noexcept
override
105 {
return "bad optional access"; }
109 [[__noreturn__]]
inline void
110 __throw_bad_optional_access()
111 { _GLIBCXX_THROW_OR_ABORT(bad_optional_access()); }
115 template <
typename _Tp>
116 struct _Optional_payload_base
118 using _Stored_type = remove_const_t<_Tp>;
120 _Optional_payload_base() =
default;
121 ~_Optional_payload_base() =
default;
123 template<
typename... _Args>
125 _Optional_payload_base(in_place_t __tag, _Args&&... __args)
126 : _M_payload(__tag, std::
forward<_Args>(__args)...),
130 template<
typename _Up,
typename... _Args>
134 : _M_payload(__il, std::
forward<_Args>(__args)...),
141 _Optional_payload_base(
bool __engaged,
142 const _Optional_payload_base& __other)
144 if (__other._M_engaged)
145 this->_M_construct(__other._M_get());
151 _Optional_payload_base(
bool __engaged,
152 _Optional_payload_base&& __other)
154 if (__other._M_engaged)
155 this->_M_construct(
std::move(__other._M_get()));
160 _Optional_payload_base(
const _Optional_payload_base&) =
default;
164 _Optional_payload_base(_Optional_payload_base&&) =
default;
166 _Optional_payload_base&
167 operator=(
const _Optional_payload_base&) =
default;
169 _Optional_payload_base&
170 operator=(_Optional_payload_base&&) =
default;
174 _M_copy_assign(
const _Optional_payload_base& __other)
176 if (this->_M_engaged && __other._M_engaged)
177 this->_M_get() = __other._M_get();
180 if (__other._M_engaged)
181 this->_M_construct(__other._M_get());
189 _M_move_assign(_Optional_payload_base&& __other)
190 noexcept(__and_v<is_nothrow_move_constructible<_Tp>,
191 is_nothrow_move_assignable<_Tp>>)
193 if (this->_M_engaged && __other._M_engaged)
194 this->_M_get() =
std::move(__other._M_get());
197 if (__other._M_engaged)
198 this->_M_construct(
std::move(__other._M_get()));
204 struct _Empty_byte { };
206 template<
typename _Up,
bool = is_trivially_destructible_v<_Up>>
209 constexpr _Storage() noexcept : _M_empty() { }
211 template<
typename... _Args>
213 _Storage(in_place_t, _Args&&... __args)
214 : _M_value(std::
forward<_Args>(__args)...)
217 template<
typename _Vp,
typename... _Args>
220 : _M_value(__il, std::
forward<_Args>(__args)...)
223 #if __cplusplus >= 202002L
224 template<
typename _Fn,
typename _Arg>
226 _Storage(_Optional_func<_Fn> __f, _Arg&& __arg)
227 : _M_value(std::__invoke(std::
forward<_Fn>(__f._M_f),
232 _Empty_byte _M_empty;
236 template<
typename _Up>
237 union _Storage<_Up, false>
239 constexpr _Storage() noexcept : _M_empty() { }
241 template<
typename... _Args>
243 _Storage(in_place_t, _Args&&... __args)
244 : _M_value(std::
forward<_Args>(__args)...)
247 template<
typename _Vp,
typename... _Args>
250 : _M_value(__il, std::
forward<_Args>(__args)...)
253 #if __cplusplus >= 202002L
254 template<
typename _Fn,
typename _Arg>
256 _Storage(_Optional_func<_Fn> __f, _Arg&& __arg)
257 : _M_value(std::__invoke(std::
forward<_Fn>(__f._M_f),
263 _GLIBCXX20_CONSTEXPR ~_Storage() { }
265 _Empty_byte _M_empty;
269 _Storage<_Stored_type> _M_payload;
271 bool _M_engaged =
false;
273 template<
typename... _Args>
275 _M_construct(_Args&&... __args)
276 noexcept(is_nothrow_constructible_v<_Stored_type, _Args...>)
279 std::forward<_Args>(__args)...);
280 this->_M_engaged =
true;
284 _M_destroy() noexcept
287 _M_payload._M_value.~_Stored_type();
290 #if __cplusplus >= 202002L
291 template<
typename _Fn,
typename _Up>
293 _M_apply(_Optional_func<_Fn> __f, _Up&& __x)
296 __f, std::forward<_Up>(__x));
307 {
return this->_M_payload._M_value; }
310 _M_get() const noexcept
311 {
return this->_M_payload._M_value; }
317 if (this->_M_engaged)
323 template <
typename _Tp,
325 is_trivially_destructible_v<_Tp>,
327 is_trivially_copy_assignable_v<_Tp>
328 && is_trivially_copy_constructible_v<_Tp>,
330 is_trivially_move_assignable_v<_Tp>
331 && is_trivially_move_constructible_v<_Tp>>
332 struct _Optional_payload;
335 template <
typename _Tp>
336 struct _Optional_payload<_Tp, true, true, true>
337 : _Optional_payload_base<_Tp>
339 using _Optional_payload_base<_Tp>::_Optional_payload_base;
341 _Optional_payload() =
default;
345 template <
typename _Tp>
346 struct _Optional_payload<_Tp, true, false, true>
347 : _Optional_payload_base<_Tp>
349 using _Optional_payload_base<_Tp>::_Optional_payload_base;
351 _Optional_payload() =
default;
352 ~_Optional_payload() =
default;
353 _Optional_payload(
const _Optional_payload&) =
default;
354 _Optional_payload(_Optional_payload&&) =
default;
355 _Optional_payload& operator=(_Optional_payload&&) =
default;
360 operator=(
const _Optional_payload& __other)
362 this->_M_copy_assign(__other);
368 template <
typename _Tp>
369 struct _Optional_payload<_Tp, true, true, false>
370 : _Optional_payload_base<_Tp>
372 using _Optional_payload_base<_Tp>::_Optional_payload_base;
374 _Optional_payload() =
default;
375 ~_Optional_payload() =
default;
376 _Optional_payload(
const _Optional_payload&) =
default;
377 _Optional_payload(_Optional_payload&&) =
default;
378 _Optional_payload& operator=(
const _Optional_payload&) =
default;
383 operator=(_Optional_payload&& __other)
384 noexcept(__and_v<is_nothrow_move_constructible<_Tp>,
385 is_nothrow_move_assignable<_Tp>>)
387 this->_M_move_assign(
std::move(__other));
393 template <
typename _Tp>
394 struct _Optional_payload<_Tp, true, false, false>
395 : _Optional_payload_base<_Tp>
397 using _Optional_payload_base<_Tp>::_Optional_payload_base;
399 _Optional_payload() =
default;
400 ~_Optional_payload() =
default;
401 _Optional_payload(
const _Optional_payload&) =
default;
402 _Optional_payload(_Optional_payload&&) =
default;
407 operator=(
const _Optional_payload& __other)
409 this->_M_copy_assign(__other);
416 operator=(_Optional_payload&& __other)
417 noexcept(__and_v<is_nothrow_move_constructible<_Tp>,
418 is_nothrow_move_assignable<_Tp>>)
420 this->_M_move_assign(
std::move(__other));
426 template <
typename _Tp,
bool _Copy,
bool _Move>
427 struct _Optional_payload<_Tp, false, _Copy, _Move>
428 : _Optional_payload<_Tp, true, false, false>
431 using _Optional_payload<_Tp, true, false, false>::_Optional_payload;
432 _Optional_payload() =
default;
433 _Optional_payload(
const _Optional_payload&) =
default;
434 _Optional_payload(_Optional_payload&&) =
default;
435 _Optional_payload& operator=(
const _Optional_payload&) =
default;
436 _Optional_payload& operator=(_Optional_payload&&) =
default;
439 _GLIBCXX20_CONSTEXPR ~_Optional_payload() { this->_M_reset(); }
444 template<
typename _Tp,
typename _Dp>
445 class _Optional_base_impl
448 using _Stored_type = remove_const_t<_Tp>;
452 template<
typename... _Args>
454 _M_construct(_Args&&... __args)
455 noexcept(is_nothrow_constructible_v<_Stored_type, _Args...>)
457 static_cast<_Dp*
>(
this)->_M_payload._M_construct(
458 std::forward<_Args>(__args)...);
462 _M_destruct() noexcept
463 {
static_cast<_Dp*
>(
this)->_M_payload._M_destroy(); }
468 {
static_cast<_Dp*
>(
this)->_M_payload._M_reset(); }
470 constexpr
bool _M_is_engaged() const noexcept
471 {
return static_cast<const _Dp*
>(
this)->_M_payload._M_engaged; }
477 __glibcxx_assert(this->_M_is_engaged());
478 return static_cast<_Dp*
>(
this)->_M_payload._M_get();
482 _M_get() const noexcept
484 __glibcxx_assert(this->_M_is_engaged());
485 return static_cast<const _Dp*
>(
this)->_M_payload._M_get();
507 template<
typename _Tp,
508 bool = is_trivially_copy_constructible_v<_Tp>,
509 bool = is_trivially_move_constructible_v<_Tp>>
511 : _Optional_base_impl<_Tp, _Optional_base<_Tp>>
517 template<
typename... _Args,
518 enable_if_t<is_constructible_v<_Tp, _Args...>,
bool> =
false>
521 : _M_payload(in_place, std::forward<_Args>(__args)...)
524 template<
typename _Up,
typename... _Args,
527 _Args...>,
bool> =
false>
529 _Optional_base(in_place_t,
532 : _M_payload(in_place, __il, std::forward<_Args>(__args)...)
537 _Optional_base(
const _Optional_base& __other)
538 : _M_payload(__other._M_payload._M_engaged, __other._M_payload)
542 _Optional_base(_Optional_base&& __other)
543 noexcept(is_nothrow_move_constructible_v<_Tp>)
544 : _M_payload(__other._M_payload._M_engaged,
549 _Optional_base& operator=(
const _Optional_base&) =
default;
550 _Optional_base& operator=(_Optional_base&&) =
default;
552 _Optional_payload<_Tp> _M_payload;
555 template<
typename _Tp>
557 : _Optional_base_impl<_Tp, _Optional_base<_Tp>>
563 template<
typename... _Args,
564 enable_if_t<is_constructible_v<_Tp, _Args...>,
bool> =
false>
567 : _M_payload(in_place, std::
forward<_Args>(__args)...)
570 template<
typename _Up,
typename... _Args,
572 initializer_list<_Up>&,
573 _Args...>,
bool> =
false>
575 _Optional_base(in_place_t,
576 initializer_list<_Up> __il,
578 : _M_payload(in_place, __il, std::
forward<_Args>(__args)...)
582 constexpr _Optional_base(
const _Optional_base& __other)
583 : _M_payload(__other._M_payload._M_engaged, __other._M_payload)
586 constexpr _Optional_base(_Optional_base&& __other) =
default;
589 _Optional_base& operator=(
const _Optional_base&) =
default;
590 _Optional_base& operator=(_Optional_base&&) =
default;
592 _Optional_payload<_Tp> _M_payload;
595 template<
typename _Tp>
596 struct _Optional_base<_Tp, true, false>
597 : _Optional_base_impl<_Tp, _Optional_base<_Tp>>
600 constexpr _Optional_base() =
default;
603 template<
typename... _Args,
604 enable_if_t<is_constructible_v<_Tp, _Args...>,
bool> =
false>
606 _Optional_base(in_place_t, _Args&&... __args)
607 : _M_payload(in_place, std::
forward<_Args>(__args)...)
610 template<
typename _Up,
typename... _Args,
612 initializer_list<_Up>&,
613 _Args...>,
bool> =
false>
615 _Optional_base(in_place_t,
616 initializer_list<_Up> __il,
618 : _M_payload(in_place, __il, std::
forward<_Args>(__args)...)
622 constexpr _Optional_base(
const _Optional_base& __other) =
default;
625 _Optional_base(_Optional_base&& __other)
626 noexcept(is_nothrow_move_constructible_v<_Tp>)
627 : _M_payload(__other._M_payload._M_engaged,
628 std::
move(__other._M_payload))
632 _Optional_base& operator=(
const _Optional_base&) =
default;
633 _Optional_base& operator=(_Optional_base&&) =
default;
635 _Optional_payload<_Tp> _M_payload;
638 template<
typename _Tp>
639 struct _Optional_base<_Tp, true, true>
640 : _Optional_base_impl<_Tp, _Optional_base<_Tp>>
643 constexpr _Optional_base() =
default;
646 template<
typename... _Args,
647 enable_if_t<is_constructible_v<_Tp, _Args...>,
bool> =
false>
649 _Optional_base(in_place_t, _Args&&... __args)
650 : _M_payload(in_place, std::
forward<_Args>(__args)...)
653 template<
typename _Up,
typename... _Args,
655 initializer_list<_Up>&,
656 _Args...>,
bool> =
false>
658 _Optional_base(in_place_t,
659 initializer_list<_Up> __il,
661 : _M_payload(in_place, __il, std::
forward<_Args>(__args)...)
665 constexpr _Optional_base(
const _Optional_base& __other) =
default;
666 constexpr _Optional_base(_Optional_base&& __other) =
default;
669 _Optional_base& operator=(
const _Optional_base&) =
default;
670 _Optional_base& operator=(_Optional_base&&) =
default;
672 _Optional_payload<_Tp> _M_payload;
675 template<
typename _Tp>
678 template<
typename _Tp>
679 inline constexpr
bool __is_optional_v =
false;
680 template<
typename _Tp>
681 inline constexpr
bool __is_optional_v<optional<_Tp>> =
true;
683 template<
typename _Tp,
typename _Up>
684 using __converts_from_optional =
685 __or_<is_constructible<_Tp, const optional<_Up>&>,
686 is_constructible<_Tp, optional<_Up>&>,
687 is_constructible<_Tp, const optional<_Up>&&>,
688 is_constructible<_Tp, optional<_Up>&&>,
689 is_convertible<const optional<_Up>&, _Tp>,
690 is_convertible<optional<_Up>&, _Tp>,
691 is_convertible<const optional<_Up>&&, _Tp>,
692 is_convertible<optional<_Up>&&, _Tp>>;
694 template<
typename _Tp,
typename _Up>
695 using __assigns_from_optional =
696 __or_<is_assignable<_Tp&, const optional<_Up>&>,
697 is_assignable<_Tp&, optional<_Up>&>,
698 is_assignable<_Tp&, const optional<_Up>&&>,
699 is_assignable<_Tp&, optional<_Up>&&>>;
704 template<
typename _Tp>
706 :
private _Optional_base<_Tp>,
707 private _Enable_copy_move<
709 is_copy_constructible_v<_Tp>,
711 __and_v<is_copy_constructible<_Tp>, is_copy_assignable<_Tp>>,
713 is_move_constructible_v<_Tp>,
715 __and_v<is_move_constructible<_Tp>, is_move_assignable<_Tp>>,
719 static_assert(!is_same_v<remove_cv_t<_Tp>, nullopt_t>);
720 static_assert(!is_same_v<remove_cv_t<_Tp>, in_place_t>);
721 static_assert(!is_reference_v<_Tp>);
724 using _Base = _Optional_base<_Tp>;
727 template<
typename _Up>
728 using __not_self = __not_<is_same<optional, __remove_cvref_t<_Up>>>;
729 template<
typename _Up>
730 using __not_tag = __not_<is_same<in_place_t, __remove_cvref_t<_Up>>>;
731 template<
typename... _Cond>
732 using _Requires =
enable_if_t<__and_v<_Cond...>,
bool>;
735 using value_type = _Tp;
737 constexpr optional() noexcept { }
739 constexpr optional(nullopt_t) noexcept { }
742 template<
typename _Up = _Tp,
743 _Requires<__not_self<_Up>, __not_tag<_Up>,
744 is_constructible<_Tp, _Up>,
745 is_convertible<_Up, _Tp>> =
true>
748 noexcept(is_nothrow_constructible_v<_Tp, _Up>)
749 : _Base(std::in_place, std::
forward<_Up>(__t)) { }
751 template<
typename _Up = _Tp,
752 _Requires<__not_self<_Up>, __not_tag<_Up>,
753 is_constructible<_Tp, _Up>,
754 __not_<is_convertible<_Up, _Tp>>> =
false>
757 noexcept(is_nothrow_constructible_v<_Tp, _Up>)
758 : _Base(std::in_place, std::
forward<_Up>(__t)) { }
760 template<
typename _Up,
761 _Requires<__not_<is_same<_Tp, _Up>>,
762 is_constructible<_Tp, const _Up&>,
763 is_convertible<const _Up&, _Tp>,
764 __not_<__converts_from_optional<_Tp, _Up>>> =
true>
766 optional(
const optional<_Up>& __t)
767 noexcept(is_nothrow_constructible_v<_Tp, const _Up&>)
773 template<
typename _Up,
774 _Requires<__not_<is_same<_Tp, _Up>>,
775 is_constructible<_Tp, const _Up&>,
776 __not_<is_convertible<const _Up&, _Tp>>,
777 __not_<__converts_from_optional<_Tp, _Up>>> =
false>
779 optional(
const optional<_Up>& __t)
780 noexcept(is_nothrow_constructible_v<_Tp, const _Up&>)
786 template<
typename _Up,
787 _Requires<__not_<is_same<_Tp, _Up>>,
788 is_constructible<_Tp, _Up>,
789 is_convertible<_Up, _Tp>,
790 __not_<__converts_from_optional<_Tp, _Up>>> =
true>
792 optional(optional<_Up>&& __t)
793 noexcept(is_nothrow_constructible_v<_Tp, _Up>)
799 template<
typename _Up,
800 _Requires<__not_<is_same<_Tp, _Up>>,
801 is_constructible<_Tp, _Up>,
802 __not_<is_convertible<_Up, _Tp>>,
803 __not_<__converts_from_optional<_Tp, _Up>>> =
false>
805 optional(optional<_Up>&& __t)
806 noexcept(is_nothrow_constructible_v<_Tp, _Up>)
812 template<
typename... _Args,
813 _Requires<is_constructible<_Tp, _Args...>> =
false>
815 optional(in_place_t, _Args&&... __args)
816 noexcept(is_nothrow_constructible_v<_Tp, _Args...>)
817 : _Base(std::in_place, std::
forward<_Args>(__args)...) { }
819 template<
typename _Up,
typename... _Args,
820 _Requires<is_constructible<_Tp,
821 initializer_list<_Up>&,
824 optional(in_place_t, initializer_list<_Up> __il, _Args&&... __args)
825 noexcept(is_nothrow_constructible_v<_Tp, initializer_list<_Up>&,
827 : _Base(std::in_place, __il, std::
forward<_Args>(__args)...) { }
831 _GLIBCXX20_CONSTEXPR optional&
832 operator=(nullopt_t) noexcept
838 template<
typename _Up = _Tp>
840 enable_if_t<__and_v<__not_self<_Up>,
841 __not_<__and_<is_scalar<_Tp>,
842 is_same<_Tp, decay_t<_Up>>>>,
843 is_constructible<_Tp, _Up>,
844 is_assignable<_Tp&, _Up>>,
847 noexcept(__and_v<is_nothrow_constructible<_Tp, _Up>,
848 is_nothrow_assignable<_Tp&, _Up>>)
850 if (this->_M_is_engaged())
851 this->_M_get() = std::forward<_Up>(__u);
853 this->_M_construct(std::forward<_Up>(__u));
858 template<
typename _Up>
860 enable_if_t<__and_v<__not_<is_same<_Tp, _Up>>,
861 is_constructible<_Tp, const _Up&>,
862 is_assignable<_Tp&, const _Up&>,
863 __not_<__converts_from_optional<_Tp, _Up>>,
864 __not_<__assigns_from_optional<_Tp, _Up>>>,
866 operator=(
const optional<_Up>& __u)
867 noexcept(__and_v<is_nothrow_constructible<_Tp, const _Up&>,
868 is_nothrow_assignable<_Tp&, const _Up&>>)
872 if (this->_M_is_engaged())
873 this->_M_get() = *__u;
875 this->_M_construct(*__u);
884 template<
typename _Up>
886 enable_if_t<__and_v<__not_<is_same<_Tp, _Up>>,
887 is_constructible<_Tp, _Up>,
888 is_assignable<_Tp&, _Up>,
889 __not_<__converts_from_optional<_Tp, _Up>>,
890 __not_<__assigns_from_optional<_Tp, _Up>>>,
892 operator=(optional<_Up>&& __u)
893 noexcept(__and_v<is_nothrow_constructible<_Tp, _Up>,
894 is_nothrow_assignable<_Tp&, _Up>>)
898 if (this->_M_is_engaged())
911 template<
typename... _Args>
913 enable_if_t<is_constructible_v<_Tp, _Args...>, _Tp&>
914 emplace(_Args&&... __args)
915 noexcept(is_nothrow_constructible_v<_Tp, _Args...>)
918 this->_M_construct(std::forward<_Args>(__args)...);
919 return this->_M_get();
922 template<
typename _Up,
typename... _Args>
924 enable_if_t<is_constructible_v<_Tp, initializer_list<_Up>&, _Args...>,
926 emplace(initializer_list<_Up> __il, _Args&&... __args)
927 noexcept(is_nothrow_constructible_v<_Tp, initializer_list<_Up>&,
931 this->_M_construct(__il, std::forward<_Args>(__args)...);
932 return this->_M_get();
938 _GLIBCXX20_CONSTEXPR
void
939 swap(optional& __other)
940 noexcept(is_nothrow_move_constructible_v<_Tp>
941 && is_nothrow_swappable_v<_Tp>)
945 if (this->_M_is_engaged() && __other._M_is_engaged())
946 swap(this->_M_get(), __other._M_get());
947 else if (this->_M_is_engaged())
949 __other._M_construct(
std::move(this->_M_get()));
952 else if (__other._M_is_engaged())
954 this->_M_construct(
std::move(__other._M_get()));
955 __other._M_destruct();
961 operator->() const noexcept
965 operator->() noexcept
969 operator*() const& noexcept
970 {
return this->_M_get(); }
973 operator*()& noexcept
974 {
return this->_M_get(); }
977 operator*()&& noexcept
980 constexpr
const _Tp&&
981 operator*() const&& noexcept
984 constexpr
explicit operator bool() const noexcept
985 {
return this->_M_is_engaged(); }
987 constexpr
bool has_value() const noexcept
988 {
return this->_M_is_engaged(); }
993 if (this->_M_is_engaged())
994 return this->_M_get();
995 __throw_bad_optional_access();
1001 if (this->_M_is_engaged())
1002 return this->_M_get();
1003 __throw_bad_optional_access();
1009 if (this->_M_is_engaged())
1011 __throw_bad_optional_access();
1014 constexpr
const _Tp&&
1017 if (this->_M_is_engaged())
1019 __throw_bad_optional_access();
1022 template<
typename _Up>
1024 value_or(_Up&& __u) const&
1026 static_assert(is_copy_constructible_v<_Tp>);
1027 static_assert(is_convertible_v<_Up&&, _Tp>);
1029 if (this->_M_is_engaged())
1030 return this->_M_get();
1032 return static_cast<_Tp
>(std::forward<_Up>(__u));
1035 template<
typename _Up>
1037 value_or(_Up&& __u) &&
1039 static_assert(is_move_constructible_v<_Tp>);
1040 static_assert(is_convertible_v<_Up&&, _Tp>);
1042 if (this->_M_is_engaged())
1045 return static_cast<_Tp
>(std::forward<_Up>(__u));
1048 #if __cpp_lib_optional >= 202110L
1051 template<
typename _Fn>
1053 and_then(_Fn&& __f) &
1055 using _Up = remove_cvref_t<invoke_result_t<_Fn, _Tp&>>;
1056 static_assert(__is_optional_v<remove_cvref_t<_Up>>);
1058 return std::__invoke(std::forward<_Fn>(__f), **
this);
1063 template<
typename _Fn>
1065 and_then(_Fn&& __f) const &
1067 using _Up = remove_cvref_t<invoke_result_t<_Fn, const _Tp&>>;
1068 static_assert(__is_optional_v<_Up>);
1070 return std::__invoke(std::forward<_Fn>(__f), **
this);
1075 template<
typename _Fn>
1077 and_then(_Fn&& __f) &&
1079 using _Up = remove_cvref_t<invoke_result_t<_Fn, _Tp>>;
1080 static_assert(__is_optional_v<remove_cvref_t<_Up>>);
1082 return std::__invoke(std::forward<_Fn>(__f),
std::move(**
this));
1087 template<
typename _Fn>
1089 and_then(_Fn&& __f) const &&
1091 using _Up = remove_cvref_t<invoke_result_t<_Fn, const _Tp>>;
1092 static_assert(__is_optional_v<remove_cvref_t<_Up>>);
1094 return std::__invoke(std::forward<_Fn>(__f),
std::move(**
this));
1099 template<
typename _Fn>
1101 transform(_Fn&& __f) &
1103 using _Up = invoke_result_t<_Fn, _Tp&>;
1105 return optional<_Up>(_Optional_func<_Fn>{__f}, **
this);
1107 return optional<_Up>();
1110 template<
typename _Fn>
1112 transform(_Fn&& __f) const &
1114 using _Up = invoke_result_t<_Fn, const _Tp&>;
1116 return optional<_Up>(_Optional_func<_Fn>{__f}, **
this);
1118 return optional<_Up>();
1121 template<
typename _Fn>
1123 transform(_Fn&& __f) &&
1125 using _Up = invoke_result_t<_Fn, _Tp>;
1127 return optional<_Up>(_Optional_func<_Fn>{__f},
std::move(**
this));
1129 return optional<_Up>();
1132 template<
typename _Fn>
1134 transform(_Fn&& __f) const &&
1136 using _Up = invoke_result_t<_Fn, const _Tp>;
1138 return optional<_Up>(_Optional_func<_Fn>{__f},
std::move(**
this));
1140 return optional<_Up>();
1143 template<
typename _Fn> requires invocable<_Fn> && copy_constructible<_Tp>
1145 or_else(_Fn&& __f) const&
1147 using _Up = invoke_result_t<_Fn>;
1148 static_assert( is_same_v<remove_cvref_t<_Up>, optional> );
1153 return std::forward<_Fn>(__f)();
1156 template<
typename _Fn> requires invocable<_Fn> && move_constructible<_Tp>
1158 or_else(_Fn&& __f) &&
1160 using _Up = invoke_result_t<_Fn>;
1161 static_assert( is_same_v<remove_cvref_t<_Up>, optional> );
1166 return std::forward<_Fn>(__f)();
1170 _GLIBCXX20_CONSTEXPR
void reset() noexcept { this->_M_reset(); }
1173 #if __cplusplus >= 202002L
1174 template<
typename _Up>
friend class optional;
1176 template<
typename _Fn,
typename _Value>
1178 optional(_Optional_func<_Fn> __f, _Value&& __v)
1180 this->_M_payload._M_apply(__f, std::forward<_Value>(__v));
1185 template<
typename _Tp>
1186 using __optional_relop_t =
1187 enable_if_t<is_convertible<_Tp, bool>::value,
bool>;
1189 template<
typename _Tp,
typename _Up>
1190 using __optional_eq_t = __optional_relop_t<
1191 decltype(std::declval<const _Tp&>() == std::declval<const _Up&>())
1194 template<
typename _Tp,
typename _Up>
1195 using __optional_ne_t = __optional_relop_t<
1196 decltype(std::declval<const _Tp&>() != std::declval<const _Up&>())
1199 template<
typename _Tp,
typename _Up>
1200 using __optional_lt_t = __optional_relop_t<
1201 decltype(std::declval<const _Tp&>() < std::declval<const _Up&>())
1204 template<
typename _Tp,
typename _Up>
1205 using __optional_gt_t = __optional_relop_t<
1206 decltype(std::declval<const _Tp&>() > std::declval<const _Up&>())
1209 template<
typename _Tp,
typename _Up>
1210 using __optional_le_t = __optional_relop_t<
1211 decltype(std::declval<const _Tp&>() <= std::declval<const _Up&>())
1214 template<
typename _Tp,
typename _Up>
1215 using __optional_ge_t = __optional_relop_t<
1216 decltype(std::declval<const _Tp&>() >= std::declval<const _Up&>())
1220 template<
typename _Tp,
typename _Up>
1222 operator==(
const optional<_Tp>& __lhs,
const optional<_Up>& __rhs)
1223 -> __optional_eq_t<_Tp, _Up>
1225 return static_cast<bool>(__lhs) == static_cast<bool>(__rhs)
1226 && (!__lhs || *__lhs == *__rhs);
1229 template<
typename _Tp,
typename _Up>
1231 operator!=(
const optional<_Tp>& __lhs,
const optional<_Up>& __rhs)
1232 -> __optional_ne_t<_Tp, _Up>
1234 return static_cast<bool>(__lhs) != static_cast<bool>(__rhs)
1235 || (
static_cast<bool>(__lhs) && *__lhs != *__rhs);
1238 template<
typename _Tp,
typename _Up>
1240 operator<(const optional<_Tp>& __lhs,
const optional<_Up>& __rhs)
1241 -> __optional_lt_t<_Tp, _Up>
1243 return static_cast<bool>(__rhs) && (!__lhs || *__lhs < *__rhs);
1246 template<
typename _Tp,
typename _Up>
1248 operator>(
const optional<_Tp>& __lhs,
const optional<_Up>& __rhs)
1249 -> __optional_gt_t<_Tp, _Up>
1251 return static_cast<bool>(__lhs) && (!__rhs || *__lhs > *__rhs);
1254 template<
typename _Tp,
typename _Up>
1256 operator<=(const optional<_Tp>& __lhs,
const optional<_Up>& __rhs)
1257 -> __optional_le_t<_Tp, _Up>
1259 return !__lhs || (
static_cast<bool>(__rhs) && *__lhs <= *__rhs);
1262 template<
typename _Tp,
typename _Up>
1264 operator>=(
const optional<_Tp>& __lhs,
const optional<_Up>& __rhs)
1265 -> __optional_ge_t<_Tp, _Up>
1267 return !__rhs || (
static_cast<bool>(__lhs) && *__lhs >= *__rhs);
1270 #ifdef __cpp_lib_three_way_comparison
1271 template<
typename _Tp, three_way_comparable_with<_Tp> _Up>
1272 constexpr compare_three_way_result_t<_Tp, _Up>
1273 operator<=>(
const optional<_Tp>& __x,
const optional<_Up>& __y)
1275 return __x && __y ? *__x <=> *__y : bool(__x) <=> bool(__y);
1280 template<
typename _Tp>
1282 operator==(
const optional<_Tp>& __lhs, nullopt_t) noexcept
1285 #ifdef __cpp_lib_three_way_comparison
1286 template<
typename _Tp>
1287 constexpr strong_ordering
1288 operator<=>(
const optional<_Tp>& __x, nullopt_t) noexcept
1289 {
return bool(__x) <=>
false; }
1291 template<
typename _Tp>
1293 operator==(nullopt_t,
const optional<_Tp>& __rhs) noexcept
1296 template<
typename _Tp>
1298 operator!=(
const optional<_Tp>& __lhs, nullopt_t) noexcept
1299 {
return static_cast<bool>(__lhs); }
1301 template<
typename _Tp>
1303 operator!=(nullopt_t,
const optional<_Tp>& __rhs) noexcept
1304 {
return static_cast<bool>(__rhs); }
1306 template<
typename _Tp>
1308 operator<(const optional<_Tp>& , nullopt_t) noexcept
1311 template<
typename _Tp>
1313 operator<(nullopt_t, const optional<_Tp>& __rhs) noexcept
1314 {
return static_cast<bool>(__rhs); }
1316 template<
typename _Tp>
1318 operator>(
const optional<_Tp>& __lhs, nullopt_t) noexcept
1319 {
return static_cast<bool>(__lhs); }
1321 template<
typename _Tp>
1323 operator>(nullopt_t,
const optional<_Tp>& ) noexcept
1326 template<
typename _Tp>
1328 operator<=(const optional<_Tp>& __lhs, nullopt_t) noexcept
1331 template<
typename _Tp>
1333 operator<=(nullopt_t, const optional<_Tp>& ) noexcept
1336 template<
typename _Tp>
1338 operator>=(
const optional<_Tp>& , nullopt_t) noexcept
1341 template<
typename _Tp>
1343 operator>=(nullopt_t,
const optional<_Tp>& __rhs) noexcept
1345 #endif // three-way-comparison
1348 template<
typename _Tp,
typename _Up>
1350 operator==(
const optional<_Tp>& __lhs,
const _Up& __rhs)
1351 -> __optional_eq_t<_Tp, _Up>
1352 {
return __lhs && *__lhs == __rhs; }
1354 template<
typename _Tp,
typename _Up>
1356 operator==(
const _Up& __lhs,
const optional<_Tp>& __rhs)
1357 -> __optional_eq_t<_Up, _Tp>
1358 {
return __rhs && __lhs == *__rhs; }
1360 template<
typename _Tp,
typename _Up>
1362 operator!=(
const optional<_Tp>& __lhs,
const _Up& __rhs)
1363 -> __optional_ne_t<_Tp, _Up>
1364 {
return !__lhs || *__lhs != __rhs; }
1366 template<
typename _Tp,
typename _Up>
1368 operator!=(
const _Up& __lhs,
const optional<_Tp>& __rhs)
1369 -> __optional_ne_t<_Up, _Tp>
1370 {
return !__rhs || __lhs != *__rhs; }
1372 template<
typename _Tp,
typename _Up>
1374 operator<(const optional<_Tp>& __lhs,
const _Up& __rhs)
1375 -> __optional_lt_t<_Tp, _Up>
1376 {
return !__lhs || *__lhs < __rhs; }
1378 template<
typename _Tp,
typename _Up>
1380 operator<(const _Up& __lhs, const optional<_Tp>& __rhs)
1381 -> __optional_lt_t<_Up, _Tp>
1382 {
return __rhs && __lhs < *__rhs; }
1384 template<
typename _Tp,
typename _Up>
1386 operator>(
const optional<_Tp>& __lhs,
const _Up& __rhs)
1387 -> __optional_gt_t<_Tp, _Up>
1388 {
return __lhs && *__lhs > __rhs; }
1390 template<
typename _Tp,
typename _Up>
1392 operator>(
const _Up& __lhs,
const optional<_Tp>& __rhs)
1393 -> __optional_gt_t<_Up, _Tp>
1394 {
return !__rhs || __lhs > *__rhs; }
1396 template<
typename _Tp,
typename _Up>
1398 operator<=(const optional<_Tp>& __lhs,
const _Up& __rhs)
1399 -> __optional_le_t<_Tp, _Up>
1400 {
return !__lhs || *__lhs <= __rhs; }
1402 template<
typename _Tp,
typename _Up>
1404 operator<=(const _Up& __lhs, const optional<_Tp>& __rhs)
1405 -> __optional_le_t<_Up, _Tp>
1406 {
return __rhs && __lhs <= *__rhs; }
1408 template<
typename _Tp,
typename _Up>
1410 operator>=(
const optional<_Tp>& __lhs,
const _Up& __rhs)
1411 -> __optional_ge_t<_Tp, _Up>
1412 {
return __lhs && *__lhs >= __rhs; }
1414 template<
typename _Tp,
typename _Up>
1416 operator>=(
const _Up& __lhs,
const optional<_Tp>& __rhs)
1417 -> __optional_ge_t<_Up, _Tp>
1418 {
return !__rhs || __lhs >= *__rhs; }
1420 #ifdef __cpp_lib_three_way_comparison
1421 template<
typename _Tp,
typename _Up>
1422 requires (!__is_optional_v<_Up>)
1423 && three_way_comparable_with<_Tp, _Up>
1424 constexpr compare_three_way_result_t<_Tp, _Up>
1425 operator<=>(
const optional<_Tp>& __x,
const _Up& __v)
1426 {
return bool(__x) ? *__x <=> __v : strong_ordering::less; }
1433 template<
typename _Tp>
1434 _GLIBCXX20_CONSTEXPR
1435 inline enable_if_t<is_move_constructible_v<_Tp> && is_swappable_v<_Tp>>
1436 swap(optional<_Tp>& __lhs, optional<_Tp>& __rhs)
1437 noexcept(noexcept(__lhs.swap(__rhs)))
1438 { __lhs.swap(__rhs); }
1440 template<
typename _Tp>
1441 enable_if_t<!(is_move_constructible_v<_Tp> && is_swappable_v<_Tp>)>
1442 swap(optional<_Tp>&, optional<_Tp>&) =
delete;
1444 template<
typename _Tp>
1446 enable_if_t<is_constructible_v<decay_t<_Tp>, _Tp>,
1447 optional<decay_t<_Tp>>>
1448 make_optional(_Tp&& __t)
1449 noexcept(is_nothrow_constructible_v<optional<
decay_t<_Tp>>, _Tp>)
1450 {
return optional<decay_t<_Tp>>{ std::forward<_Tp>(__t) }; }
1452 template<
typename _Tp,
typename... _Args>
1456 make_optional(_Args&&... __args)
1457 noexcept(is_nothrow_constructible_v<_Tp, _Args...>)
1458 {
return optional<_Tp>{ in_place, std::forward<_Args>(__args)... }; }
1460 template<
typename _Tp,
typename _Up,
typename... _Args>
1462 enable_if_t<is_constructible_v<_Tp, initializer_list<_Up>&, _Args...>,
1464 make_optional(initializer_list<_Up> __il, _Args&&... __args)
1465 noexcept(is_nothrow_constructible_v<_Tp, initializer_list<_Up>&, _Args...>)
1466 {
return optional<_Tp>{ in_place, __il, std::forward<_Args>(__args)... }; }
1470 template<
typename _Tp,
typename _Up = remove_const_t<_Tp>,
1471 bool = __poison_hash<_Up>::__enable_hash_call>
1472 struct __optional_hash_call_base
1475 operator()(
const optional<_Tp>& __t)
const
1476 noexcept(noexcept(hash<_Up>{}(*__t)))
1480 constexpr
size_t __magic_disengaged_hash =
static_cast<size_t>(-3333);
1481 return __t ? hash<_Up>{}(*__t) : __magic_disengaged_hash;
1485 template<
typename _Tp,
typename _Up>
1486 struct __optional_hash_call_base<_Tp, _Up, false> {};
1488 template<
typename _Tp>
1489 struct hash<optional<_Tp>>
1490 :
private __poison_hash<remove_const_t<_Tp>>,
1491 public __optional_hash_call_base<_Tp>
1493 using result_type [[__deprecated__]] = size_t;
1494 using argument_type [[__deprecated__]] = optional<_Tp>;
1497 template<
typename _Tp>
1498 struct __is_fast_hash<hash<optional<_Tp>>> : __is_fast_hash<hash<_Tp>>
1503 #if __cpp_deduction_guides >= 201606
1504 template <
typename _Tp> optional(_Tp) -> optional<_Tp>;
1507 _GLIBCXX_END_NAMESPACE_VERSION
1512 #endif // _GLIBCXX_OPTIONAL
Base class for all library exceptions.
Class template for optional values.
constexpr std::remove_reference< _Tp >::type && move(_Tp &&__t) noexcept
Convert a value to an rvalue.
const char * what() const noexceptoverride
Class template that provides copy/move constructors of optional.
constexpr void _Construct(_Tp *__p, _Args &&...__args)
constexpr nullopt_t nullopt
Tag to disengage optional objects.
typename enable_if< _Cond, _Tp >::type enable_if_t
Alias template for enable_if.
Exception class thrown when a disengaged optional object is dereferenced.
typename decay< _Tp >::type decay_t
Alias template for decay.
constexpr _Tp && forward(typename std::remove_reference< _Tp >::type &__t) noexcept
Forward an lvalue.
Tag type to disengage optional objects.
constexpr _Tp * __addressof(_Tp &__r) noexcept
Same as C++11 std::addressof.