29 #ifndef _GLIBCXX_EXPERIMENTAL_OPTIONAL
30 #define _GLIBCXX_EXPERIMENTAL_OPTIONAL 1
44 #if __cplusplus <= 201103L
57 namespace std _GLIBCXX_VISIBILITY(default)
59 namespace experimental
61 inline namespace fundamentals_v1
63 _GLIBCXX_BEGIN_NAMESPACE_VERSION
76 #define __cpp_lib_experimental_optional 201411
81 template<
typename _Tp>
100 enum class _Construct { _Token };
103 explicit constexpr
nullopt_t(_Construct) { }
128 __throw_bad_optional_access(
const char*)
129 __attribute__((__noreturn__));
133 __throw_bad_optional_access(const
char* __s)
136 template<
typename _Tp,
typename =
void>
139 template<
typename _Tp>
140 struct _Has_addressof_mem<_Tp,
141 __void_t<decltype( std::declval<const _Tp&>().operator&() )>
145 template<
typename _Tp,
typename =
void>
148 template<
typename _Tp>
149 struct _Has_addressof_free<_Tp,
150 __void_t<decltype( operator&(std::declval<const _Tp&>()) )>
161 template<
typename _Tp>
163 : std::__or_<_Has_addressof_mem<_Tp>, _Has_addressof_free<_Tp>>::type
172 template<typename _Tp, enable_if_t<!_Has_addressof<_Tp>::value,
int>...>
179 template<typename _Tp, enable_if_t<_Has_addressof<_Tp>::value,
int>...>
195 template<
typename _Tp,
bool _ShouldProvideDestructor =
196 !is_trivially_destructible<_Tp>::value>
203 using _Stored_type = remove_const_t<_Tp>;
217 : _M_payload(__t), _M_engaged(
true) { }
219 constexpr _Optional_base(_Tp&& __t)
220 : _M_payload(std::move(__t)), _M_engaged(
true) { }
222 template<
typename... _Args>
223 constexpr
explicit _Optional_base(
in_place_t, _Args&&... __args)
224 : _M_payload(std::forward<_Args>(__args)...), _M_engaged(
true) { }
226 template<
typename _Up,
typename... _Args,
227 enable_if_t<is_constructible<_Tp,
234 : _M_payload(__il, std::forward<_Args>(__args)...),
238 _Optional_base(
const _Optional_base& __other)
240 if (__other._M_engaged)
241 this->_M_construct(__other._M_get());
244 _Optional_base(_Optional_base&& __other)
245 noexcept(is_nothrow_move_constructible<_Tp>())
247 if (__other._M_engaged)
248 this->_M_construct(std::move(__other._M_get()));
253 operator=(
const _Optional_base& __other)
255 if (this->_M_engaged && __other._M_engaged)
256 this->_M_get() = __other._M_get();
259 if (__other._M_engaged)
260 this->_M_construct(__other._M_get());
269 operator=(_Optional_base&& __other)
270 noexcept(__and_<is_nothrow_move_constructible<_Tp>,
271 is_nothrow_move_assignable<_Tp>>())
273 if (this->_M_engaged && __other._M_engaged)
274 this->_M_get() = std::move(__other._M_get());
277 if (__other._M_engaged)
278 this->_M_construct(std::move(__other._M_get()));
288 if (this->_M_engaged)
289 this->_M_payload.~_Stored_type();
295 constexpr
bool _M_is_engaged()
const noexcept
296 {
return this->_M_engaged; }
301 {
return _M_payload; }
304 _M_get()
const noexcept
305 {
return _M_payload; }
309 template<
typename... _Args>
311 _M_construct(_Args&&... __args)
312 noexcept(is_nothrow_constructible<_Stored_type, _Args...>())
315 _Stored_type(std::forward<_Args>(__args)...);
316 this->_M_engaged =
true;
322 this->_M_engaged =
false;
323 this->_M_payload.~_Stored_type();
330 if (this->_M_engaged)
335 struct _Empty_byte { };
337 _Empty_byte _M_empty;
338 _Stored_type _M_payload;
340 bool _M_engaged =
false;
345 template<
typename _Tp>
349 using _Stored_type = remove_const_t<_Tp>;
359 : _M_payload(__t), _M_engaged(
true) { }
361 constexpr _Optional_base(_Tp&& __t)
362 : _M_payload(std::move(__t)), _M_engaged(
true) { }
364 template<
typename... _Args>
365 constexpr
explicit _Optional_base(
in_place_t, _Args&&... __args)
366 : _M_payload(std::forward<_Args>(__args)...), _M_engaged(
true) { }
368 template<
typename _Up,
typename... _Args,
369 enable_if_t<is_constructible<_Tp,
376 : _M_payload(__il, std::forward<_Args>(__args)...),
379 _Optional_base(
const _Optional_base& __other)
381 if (__other._M_engaged)
382 this->_M_construct(__other._M_get());
385 _Optional_base(_Optional_base&& __other)
386 noexcept(is_nothrow_move_constructible<_Tp>())
388 if (__other._M_engaged)
389 this->_M_construct(std::move(__other._M_get()));
393 operator=(
const _Optional_base& __other)
395 if (this->_M_engaged && __other._M_engaged)
396 this->_M_get() = __other._M_get();
399 if (__other._M_engaged)
400 this->_M_construct(__other._M_get());
408 operator=(_Optional_base&& __other)
409 noexcept(__and_<is_nothrow_move_constructible<_Tp>,
410 is_nothrow_move_assignable<_Tp>>())
412 if (this->_M_engaged && __other._M_engaged)
413 this->_M_get() = std::move(__other._M_get());
416 if (__other._M_engaged)
417 this->_M_construct(std::move(__other._M_get()));
428 constexpr
bool _M_is_engaged()
const noexcept
429 {
return this->_M_engaged; }
433 {
return _M_payload; }
436 _M_get()
const noexcept
437 {
return _M_payload; }
439 template<
typename... _Args>
441 _M_construct(_Args&&... __args)
442 noexcept(is_nothrow_constructible<_Stored_type, _Args...>())
445 _Stored_type(std::forward<_Args>(__args)...);
446 this->_M_engaged =
true;
452 this->_M_engaged =
false;
453 this->_M_payload.~_Stored_type();
459 if (this->_M_engaged)
464 struct _Empty_byte { };
467 _Empty_byte _M_empty;
468 _Stored_type _M_payload;
470 bool _M_engaged =
false;
476 template<
typename _Tp>
481 is_copy_constructible<_Tp>::value,
483 __and_<is_copy_constructible<_Tp>, is_copy_assignable<_Tp>>::value,
485 is_move_constructible<_Tp>::value,
487 __and_<is_move_constructible<_Tp>, is_move_assignable<_Tp>>::value,
491 static_assert(__and_<__not_<is_same<remove_cv_t<_Tp>,
nullopt_t>>,
492 __not_<is_same<remove_cv_t<_Tp>,
in_place_t>>,
494 "Invalid instantiation of optional<T>");
500 using value_type = _Tp;
513 template<
typename _Up>
514 enable_if_t<is_same<_Tp, decay_t<_Up>>::value, optional&>
517 static_assert(__and_<is_constructible<_Tp, _Up>,
518 is_assignable<_Tp&, _Up>>(),
519 "Cannot assign to value type from argument");
521 if (this->_M_is_engaged())
522 this->_M_get() = std::forward<_Up>(__u);
524 this->_M_construct(std::forward<_Up>(__u));
529 template<
typename... _Args>
531 emplace(_Args&&... __args)
533 static_assert(is_constructible<_Tp, _Args&&...>(),
534 "Cannot emplace value type from arguments");
537 this->_M_construct(std::forward<_Args>(__args)...);
540 template<
typename _Up,
typename... _Args>
541 enable_if_t<is_constructible<_Tp, initializer_list<_Up>&,
543 emplace(initializer_list<_Up> __il, _Args&&... __args)
546 this->_M_construct(__il, std::forward<_Args>(__args)...);
553 swap(optional& __other)
554 noexcept(is_nothrow_move_constructible<_Tp>()
555 && noexcept(
swap(declval<_Tp&>(), declval<_Tp&>())))
559 if (this->_M_is_engaged() && __other._M_is_engaged())
560 swap(this->_M_get(), __other._M_get());
561 else if (this->_M_is_engaged())
563 __other._M_construct(std::move(this->_M_get()));
566 else if (__other._M_is_engaged())
568 this->_M_construct(std::move(__other._M_get()));
569 __other._M_destruct();
584 {
return this->_M_get(); }
588 {
return this->_M_get(); }
592 {
return std::move(this->_M_get()); }
594 constexpr
const _Tp&&
596 {
return std::move(this->_M_get()); }
598 constexpr
explicit operator bool() const noexcept
599 {
return this->_M_is_engaged(); }
604 return this->_M_is_engaged()
606 : (__throw_bad_optional_access(
"Attempt to access value of a "
607 "disengaged optional object"),
614 return this->_M_is_engaged()
616 : (__throw_bad_optional_access(
"Attempt to access value of a "
617 "disengaged optional object"),
624 return this->_M_is_engaged()
625 ? std::move(this->_M_get())
626 : (__throw_bad_optional_access(
"Attempt to access value of a "
627 "disengaged optional object"),
628 std::move(this->_M_get()));
631 constexpr
const _Tp&&
634 return this->_M_is_engaged()
635 ? std::move(this->_M_get())
636 : (__throw_bad_optional_access(
"Attempt to access value of a "
637 "disengaged optional object"),
638 std::move(this->_M_get()));
641 template<
typename _Up>
643 value_or(_Up&& __u) const&
645 static_assert(__and_<is_copy_constructible<_Tp>,
646 is_convertible<_Up&&, _Tp>>(),
647 "Cannot return value");
649 return this->_M_is_engaged()
651 : static_cast<_Tp>(std::
forward<_Up>(__u));
654 template<
typename _Up>
656 value_or(_Up&& __u) &&
658 static_assert(__and_<is_move_constructible<_Tp>,
659 is_convertible<_Up&&, _Tp>>(),
660 "Cannot return value" );
662 return this->_M_is_engaged()
663 ? std::move(this->_M_get())
664 : static_cast<_Tp>(std::
forward<_Up>(__u));
669 template<
typename _Tp>
671 operator==(
const optional<_Tp>& __lhs,
const optional<_Tp>& __rhs)
673 return static_cast<bool>(__lhs) == static_cast<bool>(__rhs)
674 && (!__lhs || *__lhs == *__rhs);
677 template<
typename _Tp>
679 operator!=(
const optional<_Tp>& __lhs,
const optional<_Tp>& __rhs)
680 {
return !(__lhs == __rhs); }
682 template<
typename _Tp>
684 operator<(const optional<_Tp>& __lhs,
const optional<_Tp>& __rhs)
686 return static_cast<bool>(__rhs) && (!__lhs || *__lhs < *__rhs);
689 template<
typename _Tp>
691 operator>(
const optional<_Tp>& __lhs,
const optional<_Tp>& __rhs)
692 {
return __rhs < __lhs; }
694 template<
typename _Tp>
696 operator<=(const optional<_Tp>& __lhs,
const optional<_Tp>& __rhs)
697 {
return !(__rhs < __lhs); }
699 template<
typename _Tp>
701 operator>=(
const optional<_Tp>& __lhs,
const optional<_Tp>& __rhs)
702 {
return !(__lhs < __rhs); }
705 template<
typename _Tp>
707 operator==(
const optional<_Tp>& __lhs, nullopt_t) noexcept
710 template<
typename _Tp>
712 operator==(nullopt_t,
const optional<_Tp>& __rhs) noexcept
715 template<
typename _Tp>
717 operator!=(
const optional<_Tp>& __lhs, nullopt_t) noexcept
718 {
return static_cast<bool>(__lhs); }
720 template<
typename _Tp>
722 operator!=(nullopt_t,
const optional<_Tp>& __rhs) noexcept
723 {
return static_cast<bool>(__rhs); }
725 template<
typename _Tp>
727 operator<(const optional<_Tp>& , nullopt_t) noexcept
730 template<
typename _Tp>
732 operator<(nullopt_t, const optional<_Tp>& __rhs) noexcept
733 {
return static_cast<bool>(__rhs); }
735 template<
typename _Tp>
737 operator>(
const optional<_Tp>& __lhs, nullopt_t) noexcept
738 {
return static_cast<bool>(__lhs); }
740 template<
typename _Tp>
742 operator>(nullopt_t,
const optional<_Tp>& ) noexcept
745 template<
typename _Tp>
747 operator<=(const optional<_Tp>& __lhs, nullopt_t) noexcept
750 template<
typename _Tp>
752 operator<=(nullopt_t, const optional<_Tp>& ) noexcept
755 template<
typename _Tp>
757 operator>=(
const optional<_Tp>& , nullopt_t) noexcept
760 template<
typename _Tp>
762 operator>=(nullopt_t,
const optional<_Tp>& __rhs) noexcept
766 template<
typename _Tp>
768 operator==(
const optional<_Tp>& __lhs,
const _Tp& __rhs)
769 {
return __lhs && *__lhs == __rhs; }
771 template<
typename _Tp>
773 operator==(
const _Tp& __lhs,
const optional<_Tp>& __rhs)
774 {
return __rhs && __lhs == *__rhs; }
776 template<
typename _Tp>
778 operator!=(
const optional<_Tp>& __lhs, _Tp
const& __rhs)
779 {
return !__lhs || !(*__lhs == __rhs); }
781 template<
typename _Tp>
783 operator!=(
const _Tp& __lhs,
const optional<_Tp>& __rhs)
784 {
return !__rhs || !(__lhs == *__rhs); }
786 template<
typename _Tp>
788 operator<(const optional<_Tp>& __lhs,
const _Tp& __rhs)
789 {
return !__lhs || *__lhs < __rhs; }
791 template<
typename _Tp>
793 operator<(const _Tp& __lhs, const optional<_Tp>& __rhs)
794 {
return __rhs && __lhs < *__rhs; }
796 template<
typename _Tp>
798 operator>(
const optional<_Tp>& __lhs,
const _Tp& __rhs)
799 {
return __lhs && __rhs < *__lhs; }
801 template<
typename _Tp>
803 operator>(
const _Tp& __lhs,
const optional<_Tp>& __rhs)
804 {
return !__rhs || *__rhs < __lhs; }
806 template<
typename _Tp>
808 operator<=(const optional<_Tp>& __lhs,
const _Tp& __rhs)
809 {
return !__lhs || !(__rhs < *__lhs); }
811 template<
typename _Tp>
813 operator<=(const _Tp& __lhs, const optional<_Tp>& __rhs)
814 {
return __rhs && !(*__rhs < __lhs); }
816 template<
typename _Tp>
818 operator>=(
const optional<_Tp>& __lhs,
const _Tp& __rhs)
819 {
return __lhs && !(*__lhs < __rhs); }
821 template<
typename _Tp>
823 operator>=(
const _Tp& __lhs,
const optional<_Tp>& __rhs)
824 {
return !__rhs || !(__lhs < *__rhs); }
827 template<
typename _Tp>
829 swap(optional<_Tp>& __lhs, optional<_Tp>& __rhs)
830 noexcept(noexcept(__lhs.swap(__rhs)))
831 { __lhs.swap(__rhs); }
833 template<
typename _Tp>
834 constexpr optional<decay_t<_Tp>>
835 make_optional(_Tp&& __t)
836 {
return optional<decay_t<_Tp>> { std::forward<_Tp>(__t) }; }
839 _GLIBCXX_END_NAMESPACE_VERSION
844 template<
typename _Tp>
845 struct hash<experimental::optional<_Tp>>
847 using result_type = size_t;
848 using argument_type = experimental::optional<_Tp>;
851 operator()(
const experimental::optional<_Tp>& __t)
const
852 noexcept(noexcept(hash<_Tp> {}(*__t)))
856 constexpr
size_t __magic_disengaged_hash =
static_cast<size_t>(-3333);
857 return __t ? hash<_Tp> {}(*__t) : __magic_disengaged_hash;
864 #endif // _GLIBCXX_EXPERIMENTAL_OPTIONAL
logic_error(const string &__arg)
Exception class thrown when a disengaged optional object is dereferenced.
constexpr _Tp && forward(typename std::remove_reference< _Tp >::type &__t) noexcept
Forward an lvalue.
Tag type to disengage optional objects.
_Tp * __addressof(_Tp &__r) noexcept
Same as C++11 std::addressof.
Trait that detects the presence of an overloaded unary operator&.
A mixin helper to conditionally enable or disable the copy/move special members.
Class template for optional values.
Class template that holds the necessary state for Optional values and that has the responsibility for...
Tag type for in-place construction.
constexpr _Tp * __constexpr_addressof(_Tp &__t)
An overload that attempts to take the address of an lvalue as a constant expression. Falls back to __addressof in the presence of an overloaded addressof operator (unary operator&), in which case the call will not be a constant expression.
void swap(basic_filebuf< _CharT, _Traits > &__x, basic_filebuf< _CharT, _Traits > &__y)
Swap specialization for filebufs.
constexpr in_place_t in_place
Tag for in-place construction.
constexpr nullopt_t nullopt
Tag to disengage optional objects.
One of two subclasses of exception.