29 #ifndef _GLIBCXX_OPTIONAL
30 #define _GLIBCXX_OPTIONAL 1
32 #pragma GCC system_header
34 #if __cplusplus >= 201703L
37 #include <type_traits>
44 #if __cplusplus > 201703L
48 namespace std _GLIBCXX_VISIBILITY(default)
50 _GLIBCXX_BEGIN_NAMESPACE_VERSION
57 #define __cpp_lib_optional 201606L
59 template<
typename _Tp>
77 inline constexpr nullopt_t
nullopt { nullopt_t::_Construct::_Token };
84 class bad_optional_access :
public exception
87 bad_optional_access() { }
89 virtual const char* what() const noexcept
override
90 {
return "bad optional access"; }
92 virtual ~bad_optional_access() noexcept = default;
96 __throw_bad_optional_access()
97 __attribute__((__noreturn__));
101 __throw_bad_optional_access()
102 { _GLIBCXX_THROW_OR_ABORT(bad_optional_access()); }
106 template <
typename _Tp>
107 struct _Optional_payload_base
109 using _Stored_type = remove_const_t<_Tp>;
111 _Optional_payload_base() =
default;
112 ~_Optional_payload_base() =
default;
114 template<
typename... _Args>
116 _Optional_payload_base(in_place_t __tag, _Args&&... __args)
117 : _M_payload(__tag, std::
forward<_Args>(__args)...),
121 template<
typename _Up,
typename... _Args>
125 : _M_payload(__il, std::
forward<_Args>(__args)...),
132 _Optional_payload_base(
bool __engaged,
133 const _Optional_payload_base& __other)
135 if (__other._M_engaged)
136 this->_M_construct(__other._M_get());
142 _Optional_payload_base(
bool __engaged,
143 _Optional_payload_base&& __other)
145 if (__other._M_engaged)
146 this->_M_construct(
std::move(__other._M_get()));
151 _Optional_payload_base(
const _Optional_payload_base&) =
default;
155 _Optional_payload_base(_Optional_payload_base&&) =
default;
157 _Optional_payload_base&
158 operator=(
const _Optional_payload_base&) =
default;
160 _Optional_payload_base&
161 operator=(_Optional_payload_base&&) =
default;
165 _M_copy_assign(
const _Optional_payload_base& __other)
167 if (this->_M_engaged && __other._M_engaged)
168 this->_M_get() = __other._M_get();
171 if (__other._M_engaged)
172 this->_M_construct(__other._M_get());
180 _M_move_assign(_Optional_payload_base&& __other)
181 noexcept(__and_v<is_nothrow_move_constructible<_Tp>,
182 is_nothrow_move_assignable<_Tp>>)
184 if (this->_M_engaged && __other._M_engaged)
185 this->_M_get() =
std::move(__other._M_get());
188 if (__other._M_engaged)
189 this->_M_construct(
std::move(__other._M_get()));
195 struct _Empty_byte { };
197 template<
typename _Up,
bool = is_trivially_destructible_v<_Up>>
200 constexpr _Storage() noexcept : _M_empty() { }
202 template<
typename... _Args>
204 _Storage(in_place_t, _Args&&... __args)
205 : _M_value(std::
forward<_Args>(__args)...)
208 template<
typename _Vp,
typename... _Args>
211 : _M_value(__il, std::
forward<_Args>(__args)...)
214 _Empty_byte _M_empty;
218 template<
typename _Up>
219 union _Storage<_Up, false>
221 constexpr _Storage() noexcept : _M_empty() { }
223 template<
typename... _Args>
225 _Storage(in_place_t, _Args&&... __args)
226 : _M_value(std::
forward<_Args>(__args)...)
229 template<
typename _Vp,
typename... _Args>
232 : _M_value(__il, std::
forward<_Args>(__args)...)
238 _Empty_byte _M_empty;
242 _Storage<_Stored_type> _M_payload;
244 bool _M_engaged =
false;
246 template<
typename... _Args>
248 _M_construct(_Args&&... __args)
249 noexcept(is_nothrow_constructible_v<_Stored_type, _Args...>)
252 _Stored_type(std::
forward<_Args>(__args)...);
253 this->_M_engaged = true;
257 _M_destroy() noexcept
260 _M_payload._M_value.~_Stored_type();
269 {
return this->_M_payload._M_value; }
272 _M_get() const noexcept
273 {
return this->_M_payload._M_value; }
279 if (this->_M_engaged)
285 template <
typename _Tp,
287 is_trivially_destructible_v<_Tp>,
289 is_trivially_copy_assignable_v<_Tp>
290 && is_trivially_copy_constructible_v<_Tp>,
292 is_trivially_move_assignable_v<_Tp>
293 && is_trivially_move_constructible_v<_Tp>>
294 struct _Optional_payload;
297 template <
typename _Tp>
298 struct _Optional_payload<_Tp, true, true, true>
299 : _Optional_payload_base<_Tp>
301 using _Optional_payload_base<_Tp>::_Optional_payload_base;
303 _Optional_payload() =
default;
307 template <
typename _Tp>
308 struct _Optional_payload<_Tp, true, false, true>
309 : _Optional_payload_base<_Tp>
311 using _Optional_payload_base<_Tp>::_Optional_payload_base;
313 _Optional_payload() =
default;
314 ~_Optional_payload() =
default;
315 _Optional_payload(
const _Optional_payload&) =
default;
316 _Optional_payload(_Optional_payload&&) =
default;
317 _Optional_payload& operator=(_Optional_payload&&) =
default;
322 operator=(
const _Optional_payload& __other)
324 this->_M_copy_assign(__other);
330 template <
typename _Tp>
331 struct _Optional_payload<_Tp, true, true, false>
332 : _Optional_payload_base<_Tp>
334 using _Optional_payload_base<_Tp>::_Optional_payload_base;
336 _Optional_payload() =
default;
337 ~_Optional_payload() =
default;
338 _Optional_payload(
const _Optional_payload&) =
default;
339 _Optional_payload(_Optional_payload&&) =
default;
340 _Optional_payload& operator=(
const _Optional_payload&) =
default;
345 operator=(_Optional_payload&& __other)
346 noexcept(__and_v<is_nothrow_move_constructible<_Tp>,
347 is_nothrow_move_assignable<_Tp>>)
349 this->_M_move_assign(
std::move(__other));
355 template <
typename _Tp>
356 struct _Optional_payload<_Tp, true, false, false>
357 : _Optional_payload_base<_Tp>
359 using _Optional_payload_base<_Tp>::_Optional_payload_base;
361 _Optional_payload() =
default;
362 ~_Optional_payload() =
default;
363 _Optional_payload(
const _Optional_payload&) =
default;
364 _Optional_payload(_Optional_payload&&) =
default;
369 operator=(
const _Optional_payload& __other)
371 this->_M_copy_assign(__other);
378 operator=(_Optional_payload&& __other)
379 noexcept(__and_v<is_nothrow_move_constructible<_Tp>,
380 is_nothrow_move_assignable<_Tp>>)
382 this->_M_move_assign(
std::move(__other));
388 template <
typename _Tp,
bool _Copy,
bool _Move>
389 struct _Optional_payload<_Tp, false, _Copy, _Move>
390 : _Optional_payload<_Tp, true, false, false>
393 using _Optional_payload<_Tp, true, false, false>::_Optional_payload;
394 _Optional_payload() =
default;
395 _Optional_payload(
const _Optional_payload&) =
default;
396 _Optional_payload(_Optional_payload&&) =
default;
397 _Optional_payload& operator=(
const _Optional_payload&) =
default;
398 _Optional_payload& operator=(_Optional_payload&&) =
default;
401 ~_Optional_payload() { this->_M_reset(); }
406 template<
typename _Tp,
typename _Dp>
407 class _Optional_base_impl
410 using _Stored_type = remove_const_t<_Tp>;
414 template<
typename... _Args>
416 _M_construct(_Args&&... __args)
417 noexcept(is_nothrow_constructible_v<_Stored_type, _Args...>)
421 _Stored_type(std::
forward<_Args>(__args)...);
422 static_cast<_Dp*>(this)->_M_payload._M_engaged = true;
426 _M_destruct() noexcept
427 {
static_cast<_Dp*
>(
this)->_M_payload._M_destroy(); }
432 {
static_cast<_Dp*
>(
this)->_M_payload._M_reset(); }
434 constexpr
bool _M_is_engaged() const noexcept
435 {
return static_cast<const _Dp*
>(
this)->_M_payload._M_engaged; }
441 __glibcxx_assert(this->_M_is_engaged());
442 return static_cast<_Dp*
>(
this)->_M_payload._M_get();
446 _M_get() const noexcept
448 __glibcxx_assert(this->_M_is_engaged());
449 return static_cast<const _Dp*
>(
this)->_M_payload._M_get();
471 template<
typename _Tp,
472 bool = is_trivially_copy_constructible_v<_Tp>,
473 bool = is_trivially_move_constructible_v<_Tp>>
474 struct _Optional_base
475 : _Optional_base_impl<_Tp, _Optional_base<_Tp>>
478 constexpr _Optional_base() =
default;
481 template<
typename... _Args,
482 enable_if_t<is_constructible_v<_Tp, _Args&&...>,
bool> =
false>
483 constexpr
explicit _Optional_base(in_place_t, _Args&&... __args)
485 std::
forward<_Args>(__args)...) { }
487 template<
typename _Up,
typename... _Args,
489 initializer_list<_Up>&,
490 _Args&&...>,
bool> =
false>
491 constexpr
explicit _Optional_base(in_place_t,
492 initializer_list<_Up> __il,
495 __il, std::
forward<_Args>(__args)...)
499 constexpr _Optional_base(
const _Optional_base& __other)
500 : _M_payload(__other._M_payload._M_engaged,
504 constexpr _Optional_base(_Optional_base&& __other)
505 noexcept(is_nothrow_move_constructible_v<_Tp>)
506 : _M_payload(__other._M_payload._M_engaged,
507 std::
move(__other._M_payload))
511 _Optional_base& operator=(
const _Optional_base&) =
default;
512 _Optional_base& operator=(_Optional_base&&) =
default;
514 _Optional_payload<_Tp> _M_payload;
517 template<
typename _Tp>
518 struct _Optional_base<_Tp, false, true>
519 : _Optional_base_impl<_Tp, _Optional_base<_Tp>>
522 constexpr _Optional_base() =
default;
525 template<
typename... _Args,
526 enable_if_t<is_constructible_v<_Tp, _Args&&...>,
bool> =
false>
527 constexpr
explicit _Optional_base(in_place_t, _Args&&... __args)
529 std::
forward<_Args>(__args)...) { }
531 template<
typename _Up,
typename... _Args,
533 initializer_list<_Up>&,
534 _Args&&...>,
bool> =
false>
535 constexpr
explicit _Optional_base(in_place_t,
536 initializer_list<_Up> __il,
539 __il, std::
forward<_Args>(__args)...)
543 constexpr _Optional_base(
const _Optional_base& __other)
544 : _M_payload(__other._M_payload._M_engaged,
548 constexpr _Optional_base(_Optional_base&& __other) =
default;
551 _Optional_base& operator=(
const _Optional_base&) =
default;
552 _Optional_base& operator=(_Optional_base&&) =
default;
554 _Optional_payload<_Tp> _M_payload;
557 template<
typename _Tp>
558 struct _Optional_base<_Tp, true, false>
559 : _Optional_base_impl<_Tp, _Optional_base<_Tp>>
562 constexpr _Optional_base() =
default;
565 template<
typename... _Args,
566 enable_if_t<is_constructible_v<_Tp, _Args&&...>,
bool> =
false>
567 constexpr
explicit _Optional_base(in_place_t, _Args&&... __args)
569 std::
forward<_Args>(__args)...) { }
571 template<
typename _Up,
typename... _Args,
573 initializer_list<_Up>&,
574 _Args&&...>,
bool> =
false>
575 constexpr
explicit _Optional_base(in_place_t,
576 initializer_list<_Up> __il,
579 __il, std::
forward<_Args>(__args)...)
583 constexpr _Optional_base(
const _Optional_base& __other) =
default;
585 constexpr _Optional_base(_Optional_base&& __other)
586 noexcept(is_nothrow_move_constructible_v<_Tp>)
587 : _M_payload(__other._M_payload._M_engaged,
588 std::
move(__other._M_payload))
592 _Optional_base& operator=(
const _Optional_base&) =
default;
593 _Optional_base& operator=(_Optional_base&&) =
default;
595 _Optional_payload<_Tp> _M_payload;
598 template<
typename _Tp>
599 struct _Optional_base<_Tp, true, true>
600 : _Optional_base_impl<_Tp, _Optional_base<_Tp>>
603 constexpr _Optional_base() =
default;
606 template<
typename... _Args,
607 enable_if_t<is_constructible_v<_Tp, _Args&&...>,
bool> =
false>
608 constexpr
explicit _Optional_base(in_place_t, _Args&&... __args)
610 std::
forward<_Args>(__args)...) { }
612 template<
typename _Up,
typename... _Args,
614 initializer_list<_Up>&,
615 _Args&&...>,
bool> =
false>
616 constexpr
explicit _Optional_base(in_place_t,
617 initializer_list<_Up> __il,
620 __il, std::
forward<_Args>(__args)...)
624 constexpr _Optional_base(
const _Optional_base& __other) =
default;
625 constexpr _Optional_base(_Optional_base&& __other) =
default;
628 _Optional_base& operator=(
const _Optional_base&) =
default;
629 _Optional_base& operator=(_Optional_base&&) =
default;
631 _Optional_payload<_Tp> _M_payload;
634 template<
typename _Tp>
637 template<
typename _Tp,
typename _Up>
638 using __converts_from_optional =
639 __or_<is_constructible<_Tp, const optional<_Up>&>,
640 is_constructible<_Tp, optional<_Up>&>,
641 is_constructible<_Tp, const optional<_Up>&&>,
642 is_constructible<_Tp, optional<_Up>&&>,
643 is_convertible<const optional<_Up>&, _Tp>,
644 is_convertible<optional<_Up>&, _Tp>,
645 is_convertible<const optional<_Up>&&, _Tp>,
646 is_convertible<optional<_Up>&&, _Tp>>;
648 template<
typename _Tp,
typename _Up>
649 using __assigns_from_optional =
650 __or_<is_assignable<_Tp&, const optional<_Up>&>,
651 is_assignable<_Tp&, optional<_Up>&>,
652 is_assignable<_Tp&, const optional<_Up>&&>,
653 is_assignable<_Tp&, optional<_Up>&&>>;
658 template<
typename _Tp>
660 :
private _Optional_base<_Tp>,
661 private _Enable_copy_move<
663 is_copy_constructible_v<_Tp>,
665 __and_v<is_copy_constructible<_Tp>, is_copy_assignable<_Tp>>,
667 is_move_constructible_v<_Tp>,
669 __and_v<is_move_constructible<_Tp>, is_move_assignable<_Tp>>,
673 static_assert(!is_same_v<remove_cv_t<_Tp>, nullopt_t>);
674 static_assert(!is_same_v<remove_cv_t<_Tp>, in_place_t>);
675 static_assert(!is_reference_v<_Tp>);
678 using _Base = _Optional_base<_Tp>;
681 template<
typename _Up>
682 using __not_self = __not_<is_same<optional, __remove_cvref_t<_Up>>>;
683 template<
typename _Up>
684 using __not_tag = __not_<is_same<in_place_t, __remove_cvref_t<_Up>>>;
685 template<
typename... _Cond>
686 using _Requires =
enable_if_t<__and_v<_Cond...>,
bool>;
689 using value_type = _Tp;
691 constexpr optional() =
default;
693 constexpr optional(nullopt_t) noexcept { }
696 template<
typename _Up = _Tp,
697 _Requires<__not_self<_Up>, __not_tag<_Up>,
698 is_constructible<_Tp, _Up&&>,
699 is_convertible<_Up&&, _Tp>> =
true>
704 template<
typename _Up = _Tp,
705 _Requires<__not_self<_Up>, __not_tag<_Up>,
706 is_constructible<_Tp, _Up&&>,
707 __not_<is_convertible<_Up&&, _Tp>>> =
false>
712 template<
typename _Up,
713 _Requires<__not_<is_same<_Tp, _Up>>,
714 is_constructible<_Tp, const _Up&>,
715 is_convertible<const _Up&, _Tp>,
716 __not_<__converts_from_optional<_Tp, _Up>>> =
true>
718 optional(
const optional<_Up>& __t)
724 template<
typename _Up,
725 _Requires<__not_<is_same<_Tp, _Up>>,
726 is_constructible<_Tp, const _Up&>,
727 __not_<is_convertible<const _Up&, _Tp>>,
728 __not_<__converts_from_optional<_Tp, _Up>>> =
false>
730 optional(
const optional<_Up>& __t)
736 template <
typename _Up,
737 _Requires<__not_<is_same<_Tp, _Up>>,
738 is_constructible<_Tp, _Up&&>,
739 is_convertible<_Up&&, _Tp>,
740 __not_<__converts_from_optional<_Tp, _Up>>> =
true>
742 optional(optional<_Up>&& __t)
748 template <
typename _Up,
749 _Requires<__not_<is_same<_Tp, _Up>>,
750 is_constructible<_Tp, _Up&&>,
751 __not_<is_convertible<_Up&&, _Tp>>,
752 __not_<__converts_from_optional<_Tp, _Up>>> =
false>
754 optional(optional<_Up>&& __t)
760 template<
typename... _Args,
761 _Requires<is_constructible<_Tp, _Args&&...>> =
false>
763 optional(in_place_t, _Args&&... __args)
766 template<
typename _Up,
typename... _Args,
767 _Requires<is_constructible<_Tp,
768 initializer_list<_Up>&,
769 _Args&&...>> =
false>
771 optional(in_place_t, initializer_list<_Up> __il, _Args&&... __args)
776 operator=(nullopt_t) noexcept
782 template<
typename _Up = _Tp>
783 enable_if_t<__and_v<__not_self<_Up>,
784 __not_<__and_<is_scalar<_Tp>,
785 is_same<_Tp, decay_t<_Up>>>>,
786 is_constructible<_Tp, _Up>,
787 is_assignable<_Tp&, _Up>>,
791 if (this->_M_is_engaged())
792 this->_M_get() = std::forward<_Up>(__u);
794 this->_M_construct(std::forward<_Up>(__u));
799 template<
typename _Up>
800 enable_if_t<__and_v<__not_<is_same<_Tp, _Up>>,
801 is_constructible<_Tp, const _Up&>,
802 is_assignable<_Tp&, _Up>,
803 __not_<__converts_from_optional<_Tp, _Up>>,
804 __not_<__assigns_from_optional<_Tp, _Up>>>,
806 operator=(
const optional<_Up>& __u)
810 if (this->_M_is_engaged())
811 this->_M_get() = *__u;
813 this->_M_construct(*__u);
822 template<
typename _Up>
823 enable_if_t<__and_v<__not_<is_same<_Tp, _Up>>,
824 is_constructible<_Tp, _Up>,
825 is_assignable<_Tp&, _Up>,
826 __not_<__converts_from_optional<_Tp, _Up>>,
827 __not_<__assigns_from_optional<_Tp, _Up>>>,
829 operator=(optional<_Up>&& __u)
833 if (this->_M_is_engaged())
846 template<
typename... _Args>
847 enable_if_t<is_constructible_v<_Tp, _Args&&...>, _Tp&>
848 emplace(_Args&&... __args)
851 this->_M_construct(std::forward<_Args>(__args)...);
852 return this->_M_get();
855 template<
typename _Up,
typename... _Args>
856 enable_if_t<is_constructible_v<_Tp, initializer_list<_Up>&,
858 emplace(initializer_list<_Up> __il, _Args&&... __args)
861 this->_M_construct(__il, std::forward<_Args>(__args)...);
862 return this->_M_get();
869 swap(optional& __other)
870 noexcept(is_nothrow_move_constructible_v<_Tp>
871 && is_nothrow_swappable_v<_Tp>)
875 if (this->_M_is_engaged() && __other._M_is_engaged())
876 swap(this->_M_get(), __other._M_get());
877 else if (this->_M_is_engaged())
879 __other._M_construct(
std::move(this->_M_get()));
882 else if (__other._M_is_engaged())
884 this->_M_construct(
std::move(__other._M_get()));
885 __other._M_destruct();
900 {
return this->_M_get(); }
904 {
return this->_M_get(); }
910 constexpr
const _Tp&&
914 constexpr
explicit operator bool() const noexcept
915 {
return this->_M_is_engaged(); }
917 constexpr
bool has_value() const noexcept
918 {
return this->_M_is_engaged(); }
923 return this->_M_is_engaged()
925 : (__throw_bad_optional_access(), this->_M_get());
931 return this->_M_is_engaged()
933 : (__throw_bad_optional_access(), this->_M_get());
939 return this->_M_is_engaged()
941 : (__throw_bad_optional_access(), std::
move(this->_M_get()));
944 constexpr
const _Tp&&
947 return this->_M_is_engaged()
949 : (__throw_bad_optional_access(), std::
move(this->_M_get()));
952 template<
typename _Up>
954 value_or(_Up&& __u) const&
956 static_assert(is_copy_constructible_v<_Tp>);
957 static_assert(is_convertible_v<_Up&&, _Tp>);
959 return this->_M_is_engaged()
960 ? this->_M_get() : static_cast<_Tp>(std::
forward<_Up>(__u));
963 template<
typename _Up>
965 value_or(_Up&& __u) &&
967 static_assert(is_move_constructible_v<_Tp>);
968 static_assert(is_convertible_v<_Up&&, _Tp>);
970 return this->_M_is_engaged()
972 : static_cast<_Tp>(std::
forward<_Up>(__u));
975 void reset() noexcept { this->_M_reset(); }
978 template<
typename _Tp>
979 using __optional_relop_t =
980 enable_if_t<is_convertible<_Tp, bool>::value,
bool>;
982 template<
typename _Tp,
typename _Up>
983 using __optional_eq_t = __optional_relop_t<
984 decltype(std::declval<const _Tp&>() == std::declval<const _Up&>())
987 template<
typename _Tp,
typename _Up>
988 using __optional_ne_t = __optional_relop_t<
989 decltype(std::declval<const _Tp&>() != std::declval<const _Up&>())
992 template<
typename _Tp,
typename _Up>
993 using __optional_lt_t = __optional_relop_t<
994 decltype(std::declval<const _Tp&>() < std::declval<const _Up&>())
997 template<
typename _Tp,
typename _Up>
998 using __optional_gt_t = __optional_relop_t<
999 decltype(std::declval<const _Tp&>() > std::declval<const _Up&>())
1002 template<
typename _Tp,
typename _Up>
1003 using __optional_le_t = __optional_relop_t<
1004 decltype(std::declval<const _Tp&>() <= std::declval<const _Up&>())
1007 template<
typename _Tp,
typename _Up>
1008 using __optional_ge_t = __optional_relop_t<
1009 decltype(std::declval<const _Tp&>() >= std::declval<const _Up&>())
1013 template<
typename _Tp,
typename _Up>
1015 operator==(
const optional<_Tp>& __lhs,
const optional<_Up>& __rhs)
1016 -> __optional_eq_t<_Tp, _Up>
1018 return static_cast<bool>(__lhs) == static_cast<bool>(__rhs)
1019 && (!__lhs || *__lhs == *__rhs);
1022 template<
typename _Tp,
typename _Up>
1024 operator!=(
const optional<_Tp>& __lhs,
const optional<_Up>& __rhs)
1025 -> __optional_ne_t<_Tp, _Up>
1027 return static_cast<bool>(__lhs) != static_cast<bool>(__rhs)
1028 || (
static_cast<bool>(__lhs) && *__lhs != *__rhs);
1031 template<
typename _Tp,
typename _Up>
1033 operator<(const optional<_Tp>& __lhs,
const optional<_Up>& __rhs)
1034 -> __optional_lt_t<_Tp, _Up>
1036 return static_cast<bool>(__rhs) && (!__lhs || *__lhs < *__rhs);
1039 template<
typename _Tp,
typename _Up>
1041 operator>(
const optional<_Tp>& __lhs,
const optional<_Up>& __rhs)
1042 -> __optional_gt_t<_Tp, _Up>
1044 return static_cast<bool>(__lhs) && (!__rhs || *__lhs > *__rhs);
1047 template<
typename _Tp,
typename _Up>
1049 operator<=(const optional<_Tp>& __lhs,
const optional<_Up>& __rhs)
1050 -> __optional_le_t<_Tp, _Up>
1052 return !__lhs || (
static_cast<bool>(__rhs) && *__lhs <= *__rhs);
1055 template<
typename _Tp,
typename _Up>
1057 operator>=(
const optional<_Tp>& __lhs,
const optional<_Up>& __rhs)
1058 -> __optional_ge_t<_Tp, _Up>
1060 return !__rhs || (
static_cast<bool>(__lhs) && *__lhs >= *__rhs);
1063 #ifdef __cpp_lib_three_way_comparison
1064 template<
typename _Tp, three_way_comparable_with<_Tp> _Up>
1065 constexpr compare_three_way_result_t<_Tp, _Up>
1066 operator<=>(
const optional<_Tp>& __x,
const optional<_Up>& __y)
1068 return __x && __y ? *__x <=> *__y : bool(__x) <=> bool(__y);
1073 template<
typename _Tp>
1075 operator==(
const optional<_Tp>& __lhs, nullopt_t) noexcept
1078 #ifdef __cpp_lib_three_way_comparison
1079 template<
typename _Tp>
1080 constexpr strong_ordering
1081 operator<=>(
const optional<_Tp>& __x, nullopt_t) noexcept
1082 {
return bool(__x) <=>
false; }
1084 template<
typename _Tp>
1086 operator==(nullopt_t,
const optional<_Tp>& __rhs) noexcept
1089 template<
typename _Tp>
1091 operator!=(
const optional<_Tp>& __lhs, nullopt_t) noexcept
1092 {
return static_cast<bool>(__lhs); }
1094 template<
typename _Tp>
1096 operator!=(nullopt_t,
const optional<_Tp>& __rhs) noexcept
1097 {
return static_cast<bool>(__rhs); }
1099 template<
typename _Tp>
1101 operator<(const optional<_Tp>& , nullopt_t) noexcept
1104 template<
typename _Tp>
1106 operator<(nullopt_t, const optional<_Tp>& __rhs) noexcept
1107 {
return static_cast<bool>(__rhs); }
1109 template<
typename _Tp>
1111 operator>(
const optional<_Tp>& __lhs, nullopt_t) noexcept
1112 {
return static_cast<bool>(__lhs); }
1114 template<
typename _Tp>
1116 operator>(nullopt_t,
const optional<_Tp>& ) noexcept
1119 template<
typename _Tp>
1121 operator<=(const optional<_Tp>& __lhs, nullopt_t) noexcept
1124 template<
typename _Tp>
1126 operator<=(nullopt_t, const optional<_Tp>& ) noexcept
1129 template<
typename _Tp>
1131 operator>=(
const optional<_Tp>& , nullopt_t) noexcept
1134 template<
typename _Tp>
1136 operator>=(nullopt_t,
const optional<_Tp>& __rhs) noexcept
1138 #endif // three-way-comparison
1141 template<
typename _Tp,
typename _Up>
1143 operator==(
const optional<_Tp>& __lhs,
const _Up& __rhs)
1144 -> __optional_eq_t<_Tp, _Up>
1145 {
return __lhs && *__lhs == __rhs; }
1147 template<
typename _Tp,
typename _Up>
1149 operator==(
const _Up& __lhs,
const optional<_Tp>& __rhs)
1150 -> __optional_eq_t<_Up, _Tp>
1151 {
return __rhs && __lhs == *__rhs; }
1153 template<
typename _Tp,
typename _Up>
1155 operator!=(
const optional<_Tp>& __lhs,
const _Up& __rhs)
1156 -> __optional_ne_t<_Tp, _Up>
1157 {
return !__lhs || *__lhs != __rhs; }
1159 template<
typename _Tp,
typename _Up>
1161 operator!=(
const _Up& __lhs,
const optional<_Tp>& __rhs)
1162 -> __optional_ne_t<_Up, _Tp>
1163 {
return !__rhs || __lhs != *__rhs; }
1165 template<
typename _Tp,
typename _Up>
1167 operator<(const optional<_Tp>& __lhs,
const _Up& __rhs)
1168 -> __optional_lt_t<_Tp, _Up>
1169 {
return !__lhs || *__lhs < __rhs; }
1171 template<
typename _Tp,
typename _Up>
1173 operator<(const _Up& __lhs, const optional<_Tp>& __rhs)
1174 -> __optional_lt_t<_Up, _Tp>
1175 {
return __rhs && __lhs < *__rhs; }
1177 template<
typename _Tp,
typename _Up>
1179 operator>(
const optional<_Tp>& __lhs,
const _Up& __rhs)
1180 -> __optional_gt_t<_Tp, _Up>
1181 {
return __lhs && *__lhs > __rhs; }
1183 template<
typename _Tp,
typename _Up>
1185 operator>(
const _Up& __lhs,
const optional<_Tp>& __rhs)
1186 -> __optional_gt_t<_Up, _Tp>
1187 {
return !__rhs || __lhs > *__rhs; }
1189 template<
typename _Tp,
typename _Up>
1191 operator<=(const optional<_Tp>& __lhs,
const _Up& __rhs)
1192 -> __optional_le_t<_Tp, _Up>
1193 {
return !__lhs || *__lhs <= __rhs; }
1195 template<
typename _Tp,
typename _Up>
1197 operator<=(const _Up& __lhs, const optional<_Tp>& __rhs)
1198 -> __optional_le_t<_Up, _Tp>
1199 {
return __rhs && __lhs <= *__rhs; }
1201 template<
typename _Tp,
typename _Up>
1203 operator>=(
const optional<_Tp>& __lhs,
const _Up& __rhs)
1204 -> __optional_ge_t<_Tp, _Up>
1205 {
return __lhs && *__lhs >= __rhs; }
1207 template<
typename _Tp,
typename _Up>
1209 operator>=(
const _Up& __lhs,
const optional<_Tp>& __rhs)
1210 -> __optional_ge_t<_Up, _Tp>
1211 {
return !__rhs || __lhs >= *__rhs; }
1213 #ifdef __cpp_lib_three_way_comparison
1214 template<
typename _Tp,
typename _Up>
1215 constexpr compare_three_way_result_t<_Tp, _Up>
1216 operator<=>(
const optional<_Tp>& __x,
const _Up& __v)
1217 {
return bool(__x) ? *__x <=> __v : strong_ordering::less; }
1224 template<
typename _Tp>
1225 inline enable_if_t<is_move_constructible_v<_Tp> && is_swappable_v<_Tp>>
1226 swap(optional<_Tp>& __lhs, optional<_Tp>& __rhs)
1227 noexcept(noexcept(__lhs.swap(__rhs)))
1228 { __lhs.swap(__rhs); }
1230 template<
typename _Tp>
1231 enable_if_t<!(is_move_constructible_v<_Tp> && is_swappable_v<_Tp>)>
1232 swap(optional<_Tp>&, optional<_Tp>&) =
delete;
1234 template<
typename _Tp>
1235 constexpr optional<decay_t<_Tp>>
1236 make_optional(_Tp&& __t)
1237 {
return optional<decay_t<_Tp>> { std::forward<_Tp>(__t) }; }
1239 template<
typename _Tp,
typename ..._Args>
1240 constexpr optional<_Tp>
1241 make_optional(_Args&&... __args)
1242 {
return optional<_Tp> {
in_place, std::forward<_Args>(__args)... }; }
1244 template<
typename _Tp,
typename _Up,
typename ..._Args>
1245 constexpr optional<_Tp>
1246 make_optional(initializer_list<_Up> __il, _Args&&... __args)
1247 {
return optional<_Tp> {
in_place, __il, std::forward<_Args>(__args)... }; }
1251 template<
typename _Tp,
typename _Up = remove_const_t<_Tp>,
1252 bool = __poison_hash<_Up>::__enable_hash_call>
1253 struct __optional_hash_call_base
1256 operator()(
const optional<_Tp>& __t)
const
1257 noexcept(noexcept(hash<_Up>{}(*__t)))
1261 constexpr
size_t __magic_disengaged_hash =
static_cast<size_t>(-3333);
1262 return __t ? hash<_Up>{}(*__t) : __magic_disengaged_hash;
1266 template<
typename _Tp,
typename _Up>
1267 struct __optional_hash_call_base<_Tp, _Up, false> {};
1269 template<
typename _Tp>
1270 struct hash<optional<_Tp>>
1271 :
private __poison_hash<remove_const_t<_Tp>>,
1272 public __optional_hash_call_base<_Tp>
1274 using result_type [[__deprecated__]] = size_t;
1275 using argument_type [[__deprecated__]] = optional<_Tp>;
1278 template<
typename _Tp>
1279 struct __is_fast_hash<hash<optional<_Tp>>> : __is_fast_hash<hash<_Tp>>
1284 #if __cpp_deduction_guides >= 201606
1285 template <
typename _Tp> optional(_Tp) -> optional<_Tp>;
1288 _GLIBCXX_END_NAMESPACE_VERSION
1293 #endif // _GLIBCXX_OPTIONAL
constexpr _Tp * __addressof(_Tp &__r) noexcept
Same as C++11 std::addressof.
constexpr in_place_t in_place
Tag for in-place construction.
constexpr nullopt_t nullopt
Tag to disengage optional objects.
void _Construct(_Tp *__p, _Args &&...__args)
constexpr _Tp && forward(typename std::remove_reference< _Tp >::type &__t) noexcept
Forward an lvalue.
constexpr complex< _Tp > operator*(const complex< _Tp > &__x, const complex< _Tp > &__y)
Return new complex value x times y.
constexpr std::remove_reference< _Tp >::type && move(_Tp &&__t) noexcept
Convert a value to an rvalue.
typename enable_if< _Cond, _Tp >::type enable_if_t
Alias template for enable_if.