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llvm / llvm-project / libcxx / refs/heads/master / . / include / optional
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// -*- C++ -*-
//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef _LIBCPP_OPTIONAL
#define _LIBCPP_OPTIONAL
/*
optional synopsis
// C++1z
namespace std {
// [optional.optional], class template optional
template <class T>
class optional;
template<class T>
concept is-derived-from-optional = requires(const T& t) { // exposition only
[]<class U>(const optional<U>&){ }(t);
};
// [optional.nullopt], no-value state indicator
struct nullopt_t{see below };
inline constexpr nullopt_t nullopt(unspecified );
// [optional.bad.access], class bad_optional_access
class bad_optional_access;
// [optional.relops], relational operators
template <class T, class U>
constexpr bool operator==(const optional<T>&, const optional<U>&);
template <class T, class U>
constexpr bool operator!=(const optional<T>&, const optional<U>&);
template <class T, class U>
constexpr bool operator<(const optional<T>&, const optional<U>&);
template <class T, class U>
constexpr bool operator>(const optional<T>&, const optional<U>&);
template <class T, class U>
constexpr bool operator<=(const optional<T>&, const optional<U>&);
template <class T, class U>
constexpr bool operator>=(const optional<T>&, const optional<U>&);
template<class T, three_way_comparable_with<T> U>
constexpr compare_three_way_result_t<T, U>
operator<=>(const optional<T>&, const optional<U>&); // since C++20
// [optional.nullops], comparison with nullopt
template<class T> constexpr bool operator==(const optional<T>&, nullopt_t) noexcept;
template<class T> constexpr bool operator==(nullopt_t, const optional<T>&) noexcept; // until C++17
template<class T> constexpr bool operator!=(const optional<T>&, nullopt_t) noexcept; // until C++17
template<class T> constexpr bool operator!=(nullopt_t, const optional<T>&) noexcept; // until C++17
template<class T> constexpr bool operator<(const optional<T>&, nullopt_t) noexcept; // until C++17
template<class T> constexpr bool operator<(nullopt_t, const optional<T>&) noexcept; // until C++17
template<class T> constexpr bool operator<=(const optional<T>&, nullopt_t) noexcept; // until C++17
template<class T> constexpr bool operator<=(nullopt_t, const optional<T>&) noexcept; // until C++17
template<class T> constexpr bool operator>(const optional<T>&, nullopt_t) noexcept; // until C++17
template<class T> constexpr bool operator>(nullopt_t, const optional<T>&) noexcept; // until C++17
template<class T> constexpr bool operator>=(const optional<T>&, nullopt_t) noexcept; // until C++17
template<class T> constexpr bool operator>=(nullopt_t, const optional<T>&) noexcept; // until C++17
template<class T>
constexpr strong_ordering operator<=>(const optional<T>&, nullopt_t) noexcept; // since C++20
// [optional.comp.with.t], comparison with T
template<class T, class U> constexpr bool operator==(const optional<T>&, const U&);
template<class T, class U> constexpr bool operator==(const T&, const optional<U>&);
template<class T, class U> constexpr bool operator!=(const optional<T>&, const U&);
template<class T, class U> constexpr bool operator!=(const T&, const optional<U>&);
template<class T, class U> constexpr bool operator<(const optional<T>&, const U&);
template<class T, class U> constexpr bool operator<(const T&, const optional<U>&);
template<class T, class U> constexpr bool operator<=(const optional<T>&, const U&);
template<class T, class U> constexpr bool operator<=(const T&, const optional<U>&);
template<class T, class U> constexpr bool operator>(const optional<T>&, const U&);
template<class T, class U> constexpr bool operator>(const T&, const optional<U>&);
template<class T, class U> constexpr bool operator>=(const optional<T>&, const U&);
template<class T, class U> constexpr bool operator>=(const T&, const optional<U>&);
template<class T, class U>
requires (!is-derived-from-optional<U>) && three_way_comparable_with<T, U>
constexpr compare_three_way_result_t<T, U>
operator<=>(const optional<T>&, const U&); // since C++20
// [optional.specalg], specialized algorithms
template<class T>
void swap(optional<T>&, optional<T>&) noexcept(see below ); // constexpr in C++20
template<class T>
constexpr optional<see below > make_optional(T&&);
template<class T, class... Args>
constexpr optional<T> make_optional(Args&&... args);
template<class T, class U, class... Args>
constexpr optional<T> make_optional(initializer_list<U> il, Args&&... args);
// [optional.hash], hash support
template<class T> struct hash;
template<class T> struct hash<optional<T>>;
template<class T>
class optional {
public:
using value_type = T;
// [optional.ctor], constructors
constexpr optional() noexcept;
constexpr optional(nullopt_t) noexcept;
constexpr optional(const optional &);
constexpr optional(optional &&) noexcept(see below);
template<class... Args>
constexpr explicit optional(in_place_t, Args &&...);
template<class U, class... Args>
constexpr explicit optional(in_place_t, initializer_list<U>, Args &&...);
template<class U = T>
constexpr explicit(see-below) optional(U &&);
template<class U>
explicit(see-below) optional(const optional<U> &); // constexpr in C++20
template<class U>
explicit(see-below) optional(optional<U> &&); // constexpr in C++20
// [optional.dtor], destructor
~optional(); // constexpr in C++20
// [optional.assign], assignment
optional &operator=(nullopt_t) noexcept; // constexpr in C++20
constexpr optional &operator=(const optional &);
constexpr optional &operator=(optional &&) noexcept(see below);
template<class U = T> optional &operator=(U &&); // constexpr in C++20
template<class U> optional &operator=(const optional<U> &); // constexpr in C++20
template<class U> optional &operator=(optional<U> &&); // constexpr in C++20
template<class... Args> T& emplace(Args &&...); // constexpr in C++20
template<class U, class... Args> T& emplace(initializer_list<U>, Args &&...); // constexpr in C++20
// [optional.swap], swap
void swap(optional &) noexcept(see below ); // constexpr in C++20
// [optional.observe], observers
constexpr T const *operator->() const;
constexpr T *operator->();
constexpr T const &operator*() const &;
constexpr T &operator*() &;
constexpr T &&operator*() &&;
constexpr const T &&operator*() const &&;
constexpr explicit operator bool() const noexcept;
constexpr bool has_value() const noexcept;
constexpr T const &value() const &;
constexpr T &value() &;
constexpr T &&value() &&;
constexpr const T &&value() const &&;
template<class U> constexpr T value_or(U &&) const &;
template<class U> constexpr T value_or(U &&) &&;
// [optional.monadic], monadic operations
template<class F> constexpr auto and_then(F&& f) &; // since C++23
template<class F> constexpr auto and_then(F&& f) &&; // since C++23
template<class F> constexpr auto and_then(F&& f) const&; // since C++23
template<class F> constexpr auto and_then(F&& f) const&&; // since C++23
template<class F> constexpr auto transform(F&& f) &; // since C++23
template<class F> constexpr auto transform(F&& f) &&; // since C++23
template<class F> constexpr auto transform(F&& f) const&; // since C++23
template<class F> constexpr auto transform(F&& f) const&&; // since C++23
template<class F> constexpr optional or_else(F&& f) &&; // since C++23
template<class F> constexpr optional or_else(F&& f) const&; // since C++23
// [optional.mod], modifiers
void reset() noexcept; // constexpr in C++20
private:
T *val; // exposition only
};
template<class T>
optional(T) -> optional<T>;
} // namespace std
*/
#include <__assert>
#include <__availability>
#include <__compare/compare_three_way_result.h>
#include <__compare/three_way_comparable.h>
#include <__concepts/invocable.h>
#include <__config>
#include <__exception/exception.h>
#include <__functional/hash.h>
#include <__functional/invoke.h>
#include <__functional/unary_function.h>
#include <__fwd/functional.h>
#include <__memory/addressof.h>
#include <__memory/construct_at.h>
#include <__tuple/sfinae_helpers.h>
#include <__type_traits/add_pointer.h>
#include <__type_traits/conditional.h>
#include <__type_traits/conjunction.h>
#include <__type_traits/decay.h>
#include <__type_traits/disjunction.h>
#include <__type_traits/is_array.h>
#include <__type_traits/is_assignable.h>
#include <__type_traits/is_constructible.h>
#include <__type_traits/is_convertible.h>
#include <__type_traits/is_destructible.h>
#include <__type_traits/is_nothrow_assignable.h>
#include <__type_traits/is_nothrow_constructible.h>
#include <__type_traits/is_object.h>
#include <__type_traits/is_reference.h>
#include <__type_traits/is_scalar.h>
#include <__type_traits/is_swappable.h>
#include <__type_traits/is_trivially_assignable.h>
#include <__type_traits/is_trivially_constructible.h>
#include <__type_traits/is_trivially_destructible.h>
#include <__type_traits/negation.h>
#include <__type_traits/remove_const.h>
#include <__type_traits/remove_cvref.h>
#include <__type_traits/remove_reference.h>
#include <__utility/declval.h>
#include <__utility/forward.h>
#include <__utility/in_place.h>
#include <__utility/move.h>
#include <__utility/swap.h>
#include <__verbose_abort>
#include <initializer_list>
#include <new>
#include <version>
// standard-mandated includes
// [optional.syn]
#include <compare>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
#endif
_LIBCPP_PUSH_MACROS
#include <__undef_macros>
namespace std // purposefully not using versioning namespace
{
class _LIBCPP_EXPORTED_FROM_ABI _LIBCPP_AVAILABILITY_BAD_OPTIONAL_ACCESS bad_optional_access : public exception {
public:
_LIBCPP_HIDE_FROM_ABI bad_optional_access() _NOEXCEPT = default;
_LIBCPP_HIDE_FROM_ABI bad_optional_access(const bad_optional_access&) _NOEXCEPT = default;
_LIBCPP_HIDE_FROM_ABI bad_optional_access& operator=(const bad_optional_access&) _NOEXCEPT = default;
// Get the key function ~bad_optional_access() into the dylib
~bad_optional_access() _NOEXCEPT override;
const char* what() const _NOEXCEPT override;
};
} // namespace std
#if _LIBCPP_STD_VER >= 17
_LIBCPP_BEGIN_NAMESPACE_STD
_LIBCPP_NORETURN inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_THROW_BAD_OPTIONAL_ACCESS void
__throw_bad_optional_access() {
# ifndef _LIBCPP_HAS_NO_EXCEPTIONS
throw bad_optional_access();
# else
_LIBCPP_VERBOSE_ABORT("bad_optional_access was thrown in -fno-exceptions mode");
# endif
}
struct nullopt_t {
struct __secret_tag {
explicit __secret_tag() = default;
};
_LIBCPP_HIDE_FROM_ABI constexpr explicit nullopt_t(__secret_tag, __secret_tag) noexcept {}
};
inline constexpr nullopt_t nullopt{nullopt_t::__secret_tag{}, nullopt_t::__secret_tag{}};
struct __optional_construct_from_invoke_tag {};
template <class _Tp, bool = is_trivially_destructible<_Tp>::value>
struct __optional_destruct_base;
template <class _Tp>
struct __optional_destruct_base<_Tp, false> {
typedef _Tp value_type;
static_assert(is_object_v<value_type>, "instantiation of optional with a non-object type is undefined behavior");
union {
char __null_state_;
value_type __val_;
};
bool __engaged_;
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 ~__optional_destruct_base() {
if (__engaged_)
__val_.~value_type();
}
_LIBCPP_HIDE_FROM_ABI constexpr __optional_destruct_base() noexcept : __null_state_(), __engaged_(false) {}
template <class... _Args>
_LIBCPP_HIDE_FROM_ABI constexpr explicit __optional_destruct_base(in_place_t, _Args&&... __args)
: __val_(std::forward<_Args>(__args)...), __engaged_(true) {}
# if _LIBCPP_STD_VER >= 23
template <class _Fp, class... _Args>
_LIBCPP_HIDE_FROM_ABI constexpr __optional_destruct_base(
__optional_construct_from_invoke_tag, _Fp&& __f, _Args&&... __args)
: __val_(std::invoke(std::forward<_Fp>(__f), std::forward<_Args>(__args)...)), __engaged_(true) {}
# endif
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void reset() noexcept {
if (__engaged_) {
__val_.~value_type();
__engaged_ = false;
}
}
};
template <class _Tp>
struct __optional_destruct_base<_Tp, true> {
typedef _Tp value_type;
static_assert(is_object_v<value_type>, "instantiation of optional with a non-object type is undefined behavior");
union {
char __null_state_;
value_type __val_;
};
bool __engaged_;
_LIBCPP_HIDE_FROM_ABI constexpr __optional_destruct_base() noexcept : __null_state_(), __engaged_(false) {}
template <class... _Args>
_LIBCPP_HIDE_FROM_ABI constexpr explicit __optional_destruct_base(in_place_t, _Args&&... __args)
: __val_(std::forward<_Args>(__args)...), __engaged_(true) {}
# if _LIBCPP_STD_VER >= 23
template <class _Fp, class... _Args>
_LIBCPP_HIDE_FROM_ABI constexpr __optional_destruct_base(
__optional_construct_from_invoke_tag, _Fp&& __f, _Args&&... __args)
: __val_(std::invoke(std::forward<_Fp>(__f), std::forward<_Args>(__args)...)), __engaged_(true) {}
# endif
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void reset() noexcept {
if (__engaged_) {
__engaged_ = false;
}
}
};
template <class _Tp, bool = is_reference<_Tp>::value>
struct __optional_storage_base : __optional_destruct_base<_Tp> {
using __base = __optional_destruct_base<_Tp>;
using value_type = _Tp;
using __base::__base;
_LIBCPP_HIDE_FROM_ABI constexpr bool has_value() const noexcept { return this->__engaged_; }
_LIBCPP_HIDE_FROM_ABI constexpr value_type& __get() & noexcept { return this->__val_; }
_LIBCPP_HIDE_FROM_ABI constexpr const value_type& __get() const& noexcept { return this->__val_; }
_LIBCPP_HIDE_FROM_ABI constexpr value_type&& __get() && noexcept { return std::move(this->__val_); }
_LIBCPP_HIDE_FROM_ABI constexpr const value_type&& __get() const&& noexcept { return std::move(this->__val_); }
template <class... _Args>
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __construct(_Args&&... __args) {
_LIBCPP_ASSERT_INTERNAL(!has_value(), "__construct called for engaged __optional_storage");
std::__construct_at(std::addressof(this->__val_), std::forward<_Args>(__args)...);
this->__engaged_ = true;
}
template <class _That>
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __construct_from(_That&& __opt) {
if (__opt.has_value())
__construct(std::forward<_That>(__opt).__get());
}
template <class _That>
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __assign_from(_That&& __opt) {
if (this->__engaged_ == __opt.has_value()) {
if (this->__engaged_)
this->__val_ = std::forward<_That>(__opt).__get();
} else {
if (this->__engaged_)
this->reset();
else
__construct(std::forward<_That>(__opt).__get());
}
}
};
// optional<T&> is currently required to be ill-formed. However, it may
// be allowed in the future. For this reason, it has already been implemented
// to ensure we can make the change in an ABI-compatible manner.
template <class _Tp>
struct __optional_storage_base<_Tp, true> {
using value_type = _Tp;
using __raw_type = remove_reference_t<_Tp>;
__raw_type* __value_;
template <class _Up>
static _LIBCPP_HIDE_FROM_ABI constexpr bool __can_bind_reference() {
using _RawUp = __libcpp_remove_reference_t<_Up>;
using _UpPtr = _RawUp*;
using _RawTp = __libcpp_remove_reference_t<_Tp>;
using _TpPtr = _RawTp*;
using _CheckLValueArg =
integral_constant<bool,
(is_lvalue_reference<_Up>::value && is_convertible<_UpPtr, _TpPtr>::value) ||
is_same<_RawUp, reference_wrapper<_RawTp>>::value ||
is_same<_RawUp, reference_wrapper<__remove_const_t<_RawTp>>>::value >;
return (is_lvalue_reference<_Tp>::value && _CheckLValueArg::value) ||
(is_rvalue_reference<_Tp>::value && !is_lvalue_reference<_Up>::value &&
is_convertible<_UpPtr, _TpPtr>::value);
}
_LIBCPP_HIDE_FROM_ABI constexpr __optional_storage_base() noexcept : __value_(nullptr) {}
template <class _UArg>
_LIBCPP_HIDE_FROM_ABI constexpr explicit __optional_storage_base(in_place_t, _UArg&& __uarg)
: __value_(std::addressof(__uarg)) {
static_assert(__can_bind_reference<_UArg>(),
"Attempted to construct a reference element in tuple from a "
"possible temporary");
}
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void reset() noexcept { __value_ = nullptr; }
_LIBCPP_HIDE_FROM_ABI constexpr bool has_value() const noexcept { return __value_ != nullptr; }
_LIBCPP_HIDE_FROM_ABI constexpr value_type& __get() const& noexcept { return *__value_; }
_LIBCPP_HIDE_FROM_ABI constexpr value_type&& __get() const&& noexcept { return std::forward<value_type>(*__value_); }
template <class _UArg>
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __construct(_UArg&& __val) {
_LIBCPP_ASSERT_INTERNAL(!has_value(), "__construct called for engaged __optional_storage");
static_assert(__can_bind_reference<_UArg>(),
"Attempted to construct a reference element in tuple from a "
"possible temporary");
__value_ = std::addressof(__val);
}
template <class _That>
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __construct_from(_That&& __opt) {
if (__opt.has_value())
__construct(std::forward<_That>(__opt).__get());
}
template <class _That>
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void __assign_from(_That&& __opt) {
if (has_value() == __opt.has_value()) {
if (has_value())
*__value_ = std::forward<_That>(__opt).__get();
} else {
if (has_value())
reset();
else
__construct(std::forward<_That>(__opt).__get());
}
}
};
template <class _Tp, bool = is_trivially_copy_constructible<_Tp>::value>
struct __optional_copy_base : __optional_storage_base<_Tp> {
using __optional_storage_base<_Tp>::__optional_storage_base;
};
template <class _Tp>
struct __optional_copy_base<_Tp, false> : __optional_storage_base<_Tp> {
using __optional_storage_base<_Tp>::__optional_storage_base;
_LIBCPP_HIDE_FROM_ABI __optional_copy_base() = default;
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __optional_copy_base(const __optional_copy_base& __opt) {
this->__construct_from(__opt);
}
_LIBCPP_HIDE_FROM_ABI __optional_copy_base(__optional_copy_base&&) = default;
_LIBCPP_HIDE_FROM_ABI __optional_copy_base& operator=(const __optional_copy_base&) = default;
_LIBCPP_HIDE_FROM_ABI __optional_copy_base& operator=(__optional_copy_base&&) = default;
};
template <class _Tp, bool = is_trivially_move_constructible<_Tp>::value>
struct __optional_move_base : __optional_copy_base<_Tp> {
using __optional_copy_base<_Tp>::__optional_copy_base;
};
template <class _Tp>
struct __optional_move_base<_Tp, false> : __optional_copy_base<_Tp> {
using value_type = _Tp;
using __optional_copy_base<_Tp>::__optional_copy_base;
_LIBCPP_HIDE_FROM_ABI __optional_move_base() = default;
_LIBCPP_HIDE_FROM_ABI __optional_move_base(const __optional_move_base&) = default;
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
__optional_move_base(__optional_move_base&& __opt) noexcept(is_nothrow_move_constructible_v<value_type>) {
this->__construct_from(std::move(__opt));
}
_LIBCPP_HIDE_FROM_ABI __optional_move_base& operator=(const __optional_move_base&) = default;
_LIBCPP_HIDE_FROM_ABI __optional_move_base& operator=(__optional_move_base&&) = default;
};
template <class _Tp,
bool = is_trivially_destructible<_Tp>::value && is_trivially_copy_constructible<_Tp>::value &&
is_trivially_copy_assignable<_Tp>::value>
struct __optional_copy_assign_base : __optional_move_base<_Tp> {
using __optional_move_base<_Tp>::__optional_move_base;
};
template <class _Tp>
struct __optional_copy_assign_base<_Tp, false> : __optional_move_base<_Tp> {
using __optional_move_base<_Tp>::__optional_move_base;
_LIBCPP_HIDE_FROM_ABI __optional_copy_assign_base() = default;
_LIBCPP_HIDE_FROM_ABI __optional_copy_assign_base(const __optional_copy_assign_base&) = default;
_LIBCPP_HIDE_FROM_ABI __optional_copy_assign_base(__optional_copy_assign_base&&) = default;
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __optional_copy_assign_base&
operator=(const __optional_copy_assign_base& __opt) {
this->__assign_from(__opt);
return *this;
}
_LIBCPP_HIDE_FROM_ABI __optional_copy_assign_base& operator=(__optional_copy_assign_base&&) = default;
};
template <class _Tp,
bool = is_trivially_destructible<_Tp>::value && is_trivially_move_constructible<_Tp>::value &&
is_trivially_move_assignable<_Tp>::value>
struct __optional_move_assign_base : __optional_copy_assign_base<_Tp> {
using __optional_copy_assign_base<_Tp>::__optional_copy_assign_base;
};
template <class _Tp>
struct __optional_move_assign_base<_Tp, false> : __optional_copy_assign_base<_Tp> {
using value_type = _Tp;
using __optional_copy_assign_base<_Tp>::__optional_copy_assign_base;
_LIBCPP_HIDE_FROM_ABI __optional_move_assign_base() = default;
_LIBCPP_HIDE_FROM_ABI __optional_move_assign_base(const __optional_move_assign_base& __opt) = default;
_LIBCPP_HIDE_FROM_ABI __optional_move_assign_base(__optional_move_assign_base&&) = default;
_LIBCPP_HIDE_FROM_ABI __optional_move_assign_base& operator=(const __optional_move_assign_base&) = default;
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __optional_move_assign_base&
operator=(__optional_move_assign_base&& __opt) noexcept(
is_nothrow_move_assignable_v<value_type> && is_nothrow_move_constructible_v<value_type>) {
this->__assign_from(std::move(__opt));
return *this;
}
};
template <class _Tp>
using __optional_sfinae_ctor_base_t =
__sfinae_ctor_base< is_copy_constructible<_Tp>::value, is_move_constructible<_Tp>::value >;
template <class _Tp>
using __optional_sfinae_assign_base_t =
__sfinae_assign_base< (is_copy_constructible<_Tp>::value && is_copy_assignable<_Tp>::value),
(is_move_constructible<_Tp>::value && is_move_assignable<_Tp>::value) >;
template <class _Tp>
class optional;
# if _LIBCPP_STD_VER >= 20
template <class _Tp>
concept __is_derived_from_optional = requires(const _Tp& __t) { []<class _Up>(const optional<_Up>&) {}(__t); };
# endif // _LIBCPP_STD_VER >= 20
template <class _Tp>
struct __is_std_optional : false_type {};
template <class _Tp>
struct __is_std_optional<optional<_Tp>> : true_type {};
template <class _Tp>
class _LIBCPP_DECLSPEC_EMPTY_BASES optional
: private __optional_move_assign_base<_Tp>,
private __optional_sfinae_ctor_base_t<_Tp>,
private __optional_sfinae_assign_base_t<_Tp> {
using __base = __optional_move_assign_base<_Tp>;
public:
using value_type = _Tp;
private:
// Disable the reference extension using this static assert.
static_assert(!is_same_v<__remove_cvref_t<value_type>, in_place_t>,
"instantiation of optional with in_place_t is ill-formed");
static_assert(!is_same_v<__remove_cvref_t<value_type>, nullopt_t>,
"instantiation of optional with nullopt_t is ill-formed");
static_assert(!is_reference_v<value_type>, "instantiation of optional with a reference type is ill-formed");
static_assert(is_destructible_v<value_type>, "instantiation of optional with a non-destructible type is ill-formed");
static_assert(!is_array_v<value_type>, "instantiation of optional with an array type is ill-formed");
// LWG2756: conditionally explicit conversion from _Up
struct _CheckOptionalArgsConstructor {
template <class _Up>
_LIBCPP_HIDE_FROM_ABI static constexpr bool __enable_implicit() {
return is_constructible_v<_Tp, _Up&&> && is_convertible_v<_Up&&, _Tp>;
}
template <class _Up>
_LIBCPP_HIDE_FROM_ABI static constexpr bool __enable_explicit() {
return is_constructible_v<_Tp, _Up&&> && !is_convertible_v<_Up&&, _Tp>;
}
};
template <class _Up>
using _CheckOptionalArgsCtor =
_If< _IsNotSame<__remove_cvref_t<_Up>, in_place_t>::value && _IsNotSame<__remove_cvref_t<_Up>, optional>::value &&
(!is_same_v<remove_cv_t<_Tp>, bool> || !__is_std_optional<__remove_cvref_t<_Up>>::value),
_CheckOptionalArgsConstructor,
__check_tuple_constructor_fail >;
template <class _QualUp>
struct _CheckOptionalLikeConstructor {
template <class _Up, class _Opt = optional<_Up>>
using __check_constructible_from_opt =
_Or< is_constructible<_Tp, _Opt&>,
is_constructible<_Tp, _Opt const&>,
is_constructible<_Tp, _Opt&&>,
is_constructible<_Tp, _Opt const&&>,
is_convertible<_Opt&, _Tp>,
is_convertible<_Opt const&, _Tp>,
is_convertible<_Opt&&, _Tp>,
is_convertible<_Opt const&&, _Tp> >;
template <class _Up, class _Opt = optional<_Up>>
using __check_assignable_from_opt =
_Or< is_assignable<_Tp&, _Opt&>,
is_assignable<_Tp&, _Opt const&>,
is_assignable<_Tp&, _Opt&&>,
is_assignable<_Tp&, _Opt const&&> >;
template <class _Up, class _QUp = _QualUp>
_LIBCPP_HIDE_FROM_ABI static constexpr bool __enable_implicit() {
return is_convertible<_QUp, _Tp>::value &&
(is_same_v<remove_cv_t<_Tp>, bool> || !__check_constructible_from_opt<_Up>::value);
}
template <class _Up, class _QUp = _QualUp>
_LIBCPP_HIDE_FROM_ABI static constexpr bool __enable_explicit() {
return !is_convertible<_QUp, _Tp>::value &&
(is_same_v<remove_cv_t<_Tp>, bool> || !__check_constructible_from_opt<_Up>::value);
}
template <class _Up, class _QUp = _QualUp>
_LIBCPP_HIDE_FROM_ABI static constexpr bool __enable_assign() {
// Construction and assignability of _QUp to _Tp has already been
// checked.
return !__check_constructible_from_opt<_Up>::value && !__check_assignable_from_opt<_Up>::value;
}
};
template <class _Up, class _QualUp>
using _CheckOptionalLikeCtor =
_If< _And< _IsNotSame<_Up, _Tp>, is_constructible<_Tp, _QualUp> >::value,
_CheckOptionalLikeConstructor<_QualUp>,
__check_tuple_constructor_fail >;
template <class _Up, class _QualUp>
using _CheckOptionalLikeAssign =
_If< _And< _IsNotSame<_Up, _Tp>, is_constructible<_Tp, _QualUp>, is_assignable<_Tp&, _QualUp> >::value,
_CheckOptionalLikeConstructor<_QualUp>,
__check_tuple_constructor_fail >;
public:
_LIBCPP_HIDE_FROM_ABI constexpr optional() noexcept {}
_LIBCPP_HIDE_FROM_ABI constexpr optional(const optional&) = default;
_LIBCPP_HIDE_FROM_ABI constexpr optional(optional&&) = default;
_LIBCPP_HIDE_FROM_ABI constexpr optional(nullopt_t) noexcept {}
template <
class _InPlaceT,
class... _Args,
class = enable_if_t< _And< _IsSame<_InPlaceT, in_place_t>, is_constructible<value_type, _Args...> >::value > >
_LIBCPP_HIDE_FROM_ABI constexpr explicit optional(_InPlaceT, _Args&&... __args)
: __base(in_place, std::forward<_Args>(__args)...) {}
template <class _Up,
class... _Args,
class = enable_if_t< is_constructible_v<value_type, initializer_list<_Up>&, _Args...>> >
_LIBCPP_HIDE_FROM_ABI constexpr explicit optional(in_place_t, initializer_list<_Up> __il, _Args&&... __args)
: __base(in_place, __il, std::forward<_Args>(__args)...) {}
template <class _Up = value_type,
enable_if_t< _CheckOptionalArgsCtor<_Up>::template __enable_implicit<_Up>(), int> = 0>
_LIBCPP_HIDE_FROM_ABI constexpr optional(_Up&& __v) : __base(in_place, std::forward<_Up>(__v)) {}
template <class _Up, enable_if_t< _CheckOptionalArgsCtor<_Up>::template __enable_explicit<_Up>(), int> = 0>
_LIBCPP_HIDE_FROM_ABI constexpr explicit optional(_Up&& __v) : __base(in_place, std::forward<_Up>(__v)) {}
// LWG2756: conditionally explicit conversion from const optional<_Up>&
template <class _Up,
enable_if_t< _CheckOptionalLikeCtor<_Up, _Up const&>::template __enable_implicit<_Up>(), int> = 0>
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 optional(const optional<_Up>& __v) {
this->__construct_from(__v);
}
template <class _Up,
enable_if_t< _CheckOptionalLikeCtor<_Up, _Up const&>::template __enable_explicit<_Up>(), int> = 0>
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 explicit optional(const optional<_Up>& __v) {
this->__construct_from(__v);
}
// LWG2756: conditionally explicit conversion from optional<_Up>&&
template <class _Up, enable_if_t< _CheckOptionalLikeCtor<_Up, _Up&&>::template __enable_implicit<_Up>(), int> = 0>
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 optional(optional<_Up>&& __v) {
this->__construct_from(std::move(__v));
}
template <class _Up, enable_if_t< _CheckOptionalLikeCtor<_Up, _Up&&>::template __enable_explicit<_Up>(), int> = 0>
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 explicit optional(optional<_Up>&& __v) {
this->__construct_from(std::move(__v));
}
# if _LIBCPP_STD_VER >= 23
template <class _Fp, class... _Args>
_LIBCPP_HIDE_FROM_ABI constexpr explicit optional(__optional_construct_from_invoke_tag, _Fp&& __f, _Args&&... __args)
: __base(__optional_construct_from_invoke_tag{}, std::forward<_Fp>(__f), std::forward<_Args>(__args)...) {}
# endif
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 optional& operator=(nullopt_t) noexcept {
reset();
return *this;
}
_LIBCPP_HIDE_FROM_ABI constexpr optional& operator=(const optional&) = default;
_LIBCPP_HIDE_FROM_ABI constexpr optional& operator=(optional&&) = default;
// LWG2756
template <
class _Up = value_type,
class = enable_if_t< _And< _IsNotSame<__remove_cvref_t<_Up>, optional>,
_Or< _IsNotSame<__remove_cvref_t<_Up>, value_type>, _Not<is_scalar<value_type>> >,
is_constructible<value_type, _Up>,
is_assignable<value_type&, _Up> >::value> >
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 optional& operator=(_Up&& __v) {
if (this->has_value())
this->__get() = std::forward<_Up>(__v);
else
this->__construct(std::forward<_Up>(__v));
return *this;
}
// LWG2756
template <class _Up,
enable_if_t< _CheckOptionalLikeAssign<_Up, _Up const&>::template __enable_assign<_Up>(), int> = 0>
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 optional& operator=(const optional<_Up>& __v) {
this->__assign_from(__v);
return *this;
}
// LWG2756
template <class _Up, enable_if_t< _CheckOptionalLikeCtor<_Up, _Up&&>::template __enable_assign<_Up>(), int> = 0>
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 optional& operator=(optional<_Up>&& __v) {
this->__assign_from(std::move(__v));
return *this;
}
template <class... _Args, class = enable_if_t< is_constructible_v<value_type, _Args...> > >
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Tp& emplace(_Args&&... __args) {
reset();
this->__construct(std::forward<_Args>(__args)...);
return this->__get();
}
template <class _Up,
class... _Args,
class = enable_if_t< is_constructible_v<value_type, initializer_list<_Up>&, _Args...> > >
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Tp& emplace(initializer_list<_Up> __il, _Args&&... __args) {
reset();
this->__construct(__il, std::forward<_Args>(__args)...);
return this->__get();
}
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void
swap(optional& __opt) noexcept(is_nothrow_move_constructible_v<value_type> && is_nothrow_swappable_v<value_type>) {
if (this->has_value() == __opt.has_value()) {
using std::swap;
if (this->has_value())
swap(this->__get(), __opt.__get());
} else {
if (this->has_value()) {
__opt.__construct(std::move(this->__get()));
reset();
} else {
this->__construct(std::move(__opt.__get()));
__opt.reset();
}
}
}
_LIBCPP_HIDE_FROM_ABI constexpr add_pointer_t<value_type const> operator->() const {
_LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(this->has_value(), "optional operator-> called on a disengaged value");
return std::addressof(this->__get());
}
_LIBCPP_HIDE_FROM_ABI constexpr add_pointer_t<value_type> operator->() {
_LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(this->has_value(), "optional operator-> called on a disengaged value");
return std::addressof(this->__get());
}
_LIBCPP_HIDE_FROM_ABI constexpr const value_type& operator*() const& noexcept {
_LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(this->has_value(), "optional operator* called on a disengaged value");
return this->__get();
}
_LIBCPP_HIDE_FROM_ABI constexpr value_type& operator*() & noexcept {
_LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(this->has_value(), "optional operator* called on a disengaged value");
return this->__get();
}
_LIBCPP_HIDE_FROM_ABI constexpr value_type&& operator*() && noexcept {
_LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(this->has_value(), "optional operator* called on a disengaged value");
return std::move(this->__get());
}
_LIBCPP_HIDE_FROM_ABI constexpr const value_type&& operator*() const&& noexcept {
_LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(this->has_value(), "optional operator* called on a disengaged value");
return std::move(this->__get());
}
_LIBCPP_HIDE_FROM_ABI constexpr explicit operator bool() const noexcept { return has_value(); }
using __base::__get;
using __base::has_value;
_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_THROW_BAD_OPTIONAL_ACCESS constexpr value_type const& value() const& {
if (!this->has_value())
__throw_bad_optional_access();
return this->__get();
}
_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_THROW_BAD_OPTIONAL_ACCESS constexpr value_type& value() & {
if (!this->has_value())
__throw_bad_optional_access();
return this->__get();
}
_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_THROW_BAD_OPTIONAL_ACCESS constexpr value_type&& value() && {
if (!this->has_value())
__throw_bad_optional_access();
return std::move(this->__get());
}
_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_THROW_BAD_OPTIONAL_ACCESS constexpr value_type const&& value() const&& {
if (!this->has_value())
__throw_bad_optional_access();
return std::move(this->__get());
}
template <class _Up>
_LIBCPP_HIDE_FROM_ABI constexpr value_type value_or(_Up&& __v) const& {
static_assert(is_copy_constructible_v<value_type>, "optional<T>::value_or: T must be copy constructible");
static_assert(is_convertible_v<_Up, value_type>, "optional<T>::value_or: U must be convertible to T");
return this->has_value() ? this->__get() : static_cast<value_type>(std::forward<_Up>(__v));
}
template <class _Up>
_LIBCPP_HIDE_FROM_ABI constexpr value_type value_or(_Up&& __v) && {
static_assert(is_move_constructible_v<value_type>, "optional<T>::value_or: T must be move constructible");
static_assert(is_convertible_v<_Up, value_type>, "optional<T>::value_or: U must be convertible to T");
return this->has_value() ? std::move(this->__get()) : static_cast<value_type>(std::forward<_Up>(__v));
}
# if _LIBCPP_STD_VER >= 23
template <class _Func>
_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_THROW_BAD_OPTIONAL_ACCESS constexpr auto and_then(_Func&& __f) & {
using _Up = invoke_result_t<_Func, value_type&>;
static_assert(__is_std_optional<remove_cvref_t<_Up>>::value,
"Result of f(value()) must be a specialization of std::optional");
if (*this)
return std::invoke(std::forward<_Func>(__f), value());
return remove_cvref_t<_Up>();
}
template <class _Func>
_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_THROW_BAD_OPTIONAL_ACCESS constexpr auto and_then(_Func&& __f) const& {
using _Up = invoke_result_t<_Func, const value_type&>;
static_assert(__is_std_optional<remove_cvref_t<_Up>>::value,
"Result of f(value()) must be a specialization of std::optional");
if (*this)
return std::invoke(std::forward<_Func>(__f), value());
return remove_cvref_t<_Up>();
}
template <class _Func>
_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_THROW_BAD_OPTIONAL_ACCESS constexpr auto and_then(_Func&& __f) && {
using _Up = invoke_result_t<_Func, value_type&&>;
static_assert(__is_std_optional<remove_cvref_t<_Up>>::value,
"Result of f(std::move(value())) must be a specialization of std::optional");
if (*this)
return std::invoke(std::forward<_Func>(__f), std::move(value()));
return remove_cvref_t<_Up>();
}
template <class _Func>
_LIBCPP_HIDE_FROM_ABI constexpr auto and_then(_Func&& __f) const&& {
using _Up = invoke_result_t<_Func, const value_type&&>;
static_assert(__is_std_optional<remove_cvref_t<_Up>>::value,
"Result of f(std::move(value())) must be a specialization of std::optional");
if (*this)
return std::invoke(std::forward<_Func>(__f), std::move(value()));
return remove_cvref_t<_Up>();
}
template <class _Func>
_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_THROW_BAD_OPTIONAL_ACCESS constexpr auto transform(_Func&& __f) & {
using _Up = remove_cv_t<invoke_result_t<_Func, value_type&>>;
static_assert(!is_array_v<_Up>, "Result of f(value()) should not be an Array");
static_assert(!is_same_v<_Up, in_place_t>, "Result of f(value()) should not be std::in_place_t");
static_assert(!is_same_v<_Up, nullopt_t>, "Result of f(value()) should not be std::nullopt_t");
static_assert(is_object_v<_Up>, "Result of f(value()) should be an object type");
if (*this)
return optional<_Up>(__optional_construct_from_invoke_tag{}, std::forward<_Func>(__f), value());
return optional<_Up>();
}
template <class _Func>
_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_THROW_BAD_OPTIONAL_ACCESS constexpr auto transform(_Func&& __f) const& {
using _Up = remove_cv_t<invoke_result_t<_Func, const value_type&>>;
static_assert(!is_array_v<_Up>, "Result of f(value()) should not be an Array");
static_assert(!is_same_v<_Up, in_place_t>, "Result of f(value()) should not be std::in_place_t");
static_assert(!is_same_v<_Up, nullopt_t>, "Result of f(value()) should not be std::nullopt_t");
static_assert(is_object_v<_Up>, "Result of f(value()) should be an object type");
if (*this)
return optional<_Up>(__optional_construct_from_invoke_tag{}, std::forward<_Func>(__f), value());
return optional<_Up>();
}
template <class _Func>
_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_THROW_BAD_OPTIONAL_ACCESS constexpr auto transform(_Func&& __f) && {
using _Up = remove_cv_t<invoke_result_t<_Func, value_type&&>>;
static_assert(!is_array_v<_Up>, "Result of f(std::move(value())) should not be an Array");
static_assert(!is_same_v<_Up, in_place_t>, "Result of f(std::move(value())) should not be std::in_place_t");
static_assert(!is_same_v<_Up, nullopt_t>, "Result of f(std::move(value())) should not be std::nullopt_t");
static_assert(is_object_v<_Up>, "Result of f(std::move(value())) should be an object type");
if (*this)
return optional<_Up>(__optional_construct_from_invoke_tag{}, std::forward<_Func>(__f), std::move(value()));
return optional<_Up>();
}
template <class _Func>
_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_THROW_BAD_OPTIONAL_ACCESS constexpr auto transform(_Func&& __f) const&& {
using _Up = remove_cvref_t<invoke_result_t<_Func, const value_type&&>>;
static_assert(!is_array_v<_Up>, "Result of f(std::move(value())) should not be an Array");
static_assert(!is_same_v<_Up, in_place_t>, "Result of f(std::move(value())) should not be std::in_place_t");
static_assert(!is_same_v<_Up, nullopt_t>, "Result of f(std::move(value())) should not be std::nullopt_t");
static_assert(is_object_v<_Up>, "Result of f(std::move(value())) should be an object type");
if (*this)
return optional<_Up>(__optional_construct_from_invoke_tag{}, std::forward<_Func>(__f), std::move(value()));
return optional<_Up>();
}
template <invocable _Func>
_LIBCPP_HIDE_FROM_ABI constexpr optional or_else(_Func&& __f) const&
requires is_copy_constructible_v<value_type>
{
static_assert(is_same_v<remove_cvref_t<invoke_result_t<_Func>>, optional>,
"Result of f() should be the same type as this optional");
if (*this)
return *this;
return std::forward<_Func>(__f)();
}
template <invocable _Func>
_LIBCPP_HIDE_FROM_ABI constexpr optional or_else(_Func&& __f) &&
requires is_move_constructible_v<value_type>
{
static_assert(is_same_v<remove_cvref_t<invoke_result_t<_Func>>, optional>,
"Result of f() should be the same type as this optional");
if (*this)
return std::move(*this);
return std::forward<_Func>(__f)();
}
# endif // _LIBCPP_STD_VER >= 23
using __base::reset;
};
# if _LIBCPP_STD_VER >= 17
template <class _Tp>
optional(_Tp) -> optional<_Tp>;
# endif
// Comparisons between optionals
template <class _Tp, class _Up>
_LIBCPP_HIDE_FROM_ABI constexpr enable_if_t<
is_convertible_v<decltype(std::declval<const _Tp&>() == std::declval<const _Up&>()), bool>,
bool >
operator==(const optional<_Tp>& __x, const optional<_Up>& __y) {
if (static_cast<bool>(__x) != static_cast<bool>(__y))
return false;
if (!static_cast<bool>(__x))
return true;
return *__x == *__y;
}
template <class _Tp, class _Up>
_LIBCPP_HIDE_FROM_ABI constexpr enable_if_t<
is_convertible_v<decltype(std::declval<const _Tp&>() != std::declval<const _Up&>()), bool>,
bool >
operator!=(const optional<_Tp>& __x, const optional<_Up>& __y) {
if (static_cast<bool>(__x) != static_cast<bool>(__y))
return true;
if (!static_cast<bool>(__x))
return false;
return *__x != *__y;
}
template <class _Tp, class _Up>
_LIBCPP_HIDE_FROM_ABI constexpr enable_if_t<
is_convertible_v<decltype(std::declval<const _Tp&>() < std::declval<const _Up&>()), bool>,
bool >
operator<(const optional<_Tp>& __x, const optional<_Up>& __y) {
if (!static_cast<bool>(__y))
return false;
if (!static_cast<bool>(__x))
return true;
return *__x < *__y;
}
template <class _Tp, class _Up>
_LIBCPP_HIDE_FROM_ABI constexpr enable_if_t<
is_convertible_v<decltype(std::declval<const _Tp&>() > std::declval<const _Up&>()), bool>,
bool >
operator>(const optional<_Tp>& __x, const optional<_Up>& __y) {
if (!static_cast<bool>(__x))
return false;
if (!static_cast<bool>(__y))
return true;
return *__x > *__y;
}
template <class _Tp, class _Up>
_LIBCPP_HIDE_FROM_ABI constexpr enable_if_t<
is_convertible_v<decltype(std::declval<const _Tp&>() <= std::declval<const _Up&>()), bool>,
bool >
operator<=(const optional<_Tp>& __x, const optional<_Up>& __y) {
if (!static_cast<bool>(__x))
return true;
if (!static_cast<bool>(__y))
return false;
return *__x <= *__y;
}
template <class _Tp, class _Up>
_LIBCPP_HIDE_FROM_ABI constexpr enable_if_t<
is_convertible_v<decltype(std::declval<const _Tp&>() >= std::declval<const _Up&>()), bool>,
bool >
operator>=(const optional<_Tp>& __x, const optional<_Up>& __y) {
if (!static_cast<bool>(__y))
return true;
if (!static_cast<bool>(__x))
return false;
return *__x >= *__y;
}
# if _LIBCPP_STD_VER >= 20
template <class _Tp, three_way_comparable_with<_Tp> _Up>
_LIBCPP_HIDE_FROM_ABI constexpr compare_three_way_result_t<_Tp, _Up>
operator<=>(const optional<_Tp>& __x, const optional<_Up>& __y) {
if (__x && __y)
return *__x <=> *__y;
return __x.has_value() <=> __y.has_value();
}
# endif // _LIBCPP_STD_VER >= 20
// Comparisons with nullopt
template <class _Tp>
_LIBCPP_HIDE_FROM_ABI constexpr bool operator==(const optional<_Tp>& __x, nullopt_t) noexcept {
return !static_cast<bool>(__x);
}
# if _LIBCPP_STD_VER <= 17
template <class _Tp>
_LIBCPP_HIDE_FROM_ABI constexpr bool operator==(nullopt_t, const optional<_Tp>& __x) noexcept {
return !static_cast<bool>(__x);
}
template <class _Tp>
_LIBCPP_HIDE_FROM_ABI constexpr bool operator!=(const optional<_Tp>& __x, nullopt_t) noexcept {
return static_cast<bool>(__x);
}
template <class _Tp>
_LIBCPP_HIDE_FROM_ABI constexpr bool operator!=(nullopt_t, const optional<_Tp>& __x) noexcept {
return static_cast<bool>(__x);
}
template <class _Tp>
_LIBCPP_HIDE_FROM_ABI constexpr bool operator<(const optional<_Tp>&, nullopt_t) noexcept {
return false;
}
template <class _Tp>
_LIBCPP_HIDE_FROM_ABI constexpr bool operator<(nullopt_t, const optional<_Tp>& __x) noexcept {
return static_cast<bool>(__x);
}
template <class _Tp>
_LIBCPP_HIDE_FROM_ABI constexpr bool operator<=(const optional<_Tp>& __x, nullopt_t) noexcept {
return !static_cast<bool>(__x);
}
template <class _Tp>
_LIBCPP_HIDE_FROM_ABI constexpr bool operator<=(nullopt_t, const optional<_Tp>&) noexcept {
return true;
}
template <class _Tp>
_LIBCPP_HIDE_FROM_ABI constexpr bool operator>(const optional<_Tp>& __x, nullopt_t) noexcept {
return static_cast<bool>(__x);
}
template <class _Tp>
_LIBCPP_HIDE_FROM_ABI constexpr bool operator>(nullopt_t, const optional<_Tp>&) noexcept {
return false;
}
template <class _Tp>
_LIBCPP_HIDE_FROM_ABI constexpr bool operator>=(const optional<_Tp>&, nullopt_t) noexcept {
return true;
}
template <class _Tp>
_LIBCPP_HIDE_FROM_ABI constexpr bool operator>=(nullopt_t, const optional<_Tp>& __x) noexcept {
return !static_cast<bool>(__x);
}
# else // _LIBCPP_STD_VER <= 17
template <class _Tp>
_LIBCPP_HIDE_FROM_ABI constexpr strong_ordering operator<=>(const optional<_Tp>& __x, nullopt_t) noexcept {
return __x.has_value() <=> false;
}
# endif // _LIBCPP_STD_VER <= 17
// Comparisons with T
template <class _Tp, class _Up>
_LIBCPP_HIDE_FROM_ABI constexpr enable_if_t<
is_convertible_v<decltype(std::declval<const _Tp&>() == std::declval<const _Up&>()), bool>,
bool >
operator==(const optional<_Tp>& __x, const _Up& __v) {
return static_cast<bool>(__x) ? *__x == __v : false;
}
template <class _Tp, class _Up>
_LIBCPP_HIDE_FROM_ABI constexpr enable_if_t<
is_convertible_v<decltype(std::declval<const _Tp&>() == std::declval<const _Up&>()), bool>,
bool >
operator==(const _Tp& __v, const optional<_Up>& __x) {
return static_cast<bool>(__x) ? __v == *__x : false;
}
template <class _Tp, class _Up>
_LIBCPP_HIDE_FROM_ABI constexpr enable_if_t<
is_convertible_v<decltype(std::declval<const _Tp&>() != std::declval<const _Up&>()), bool>,
bool >
operator!=(const optional<_Tp>& __x, const _Up& __v) {
return static_cast<bool>(__x) ? *__x != __v : true;
}
template <class _Tp, class _Up>
_LIBCPP_HIDE_FROM_ABI constexpr enable_if_t<
is_convertible_v<decltype(std::declval<const _Tp&>() != std::declval<const _Up&>()), bool>,
bool >
operator!=(const _Tp& __v, const optional<_Up>& __x) {
return static_cast<bool>(__x) ? __v != *__x : true;
}
template <class _Tp, class _Up>
_LIBCPP_HIDE_FROM_ABI constexpr enable_if_t<
is_convertible_v<decltype(std::declval<const _Tp&>() < std::declval<const _Up&>()), bool>,
bool >
operator<(const optional<_Tp>& __x, const _Up& __v) {
return static_cast<bool>(__x) ? *__x < __v : true;
}
template <class _Tp, class _Up>
_LIBCPP_HIDE_FROM_ABI constexpr enable_if_t<
is_convertible_v<decltype(std::declval<const _Tp&>() < std::declval<const _Up&>()), bool>,
bool >
operator<(const _Tp& __v, const optional<_Up>& __x) {
return static_cast<bool>(__x) ? __v < *__x : false;
}
template <class _Tp, class _Up>
_LIBCPP_HIDE_FROM_ABI constexpr enable_if_t<
is_convertible_v<decltype(std::declval<const _Tp&>() <= std::declval<const _Up&>()), bool>,
bool >
operator<=(const optional<_Tp>& __x, const _Up& __v) {
return static_cast<bool>(__x) ? *__x <= __v : true;
}
template <class _Tp, class _Up>
_LIBCPP_HIDE_FROM_ABI constexpr enable_if_t<
is_convertible_v<decltype(std::declval<const _Tp&>() <= std::declval<const _Up&>()), bool>,
bool >
operator<=(const _Tp& __v, const optional<_Up>& __x) {
return static_cast<bool>(__x) ? __v <= *__x : false;
}
template <class _Tp, class _Up>
_LIBCPP_HIDE_FROM_ABI constexpr enable_if_t<
is_convertible_v<decltype(std::declval<const _Tp&>() > std::declval<const _Up&>()), bool>,
bool >
operator>(const optional<_Tp>& __x, const _Up& __v) {
return static_cast<bool>(__x) ? *__x > __v : false;
}
template <class _Tp, class _Up>
_LIBCPP_HIDE_FROM_ABI constexpr enable_if_t<
is_convertible_v<decltype(std::declval<const _Tp&>() > std::declval<const _Up&>()), bool>,
bool >
operator>(const _Tp& __v, const optional<_Up>& __x) {
return static_cast<bool>(__x) ? __v > *__x : true;
}
template <class _Tp, class _Up>
_LIBCPP_HIDE_FROM_ABI constexpr enable_if_t<
is_convertible_v<decltype(std::declval<const _Tp&>() >= std::declval<const _Up&>()), bool>,
bool >
operator>=(const optional<_Tp>& __x, const _Up& __v) {
return static_cast<bool>(__x) ? *__x >= __v : false;
}
template <class _Tp, class _Up>
_LIBCPP_HIDE_FROM_ABI constexpr enable_if_t<
is_convertible_v<decltype(std::declval<const _Tp&>() >= std::declval<const _Up&>()), bool>,
bool >
operator>=(const _Tp& __v, const optional<_Up>& __x) {
return static_cast<bool>(__x) ? __v >= *__x : true;
}
# if _LIBCPP_STD_VER >= 20
template <class _Tp, class _Up>
requires(!__is_derived_from_optional<_Up>) && three_way_comparable_with<_Tp, _Up>
_LIBCPP_HIDE_FROM_ABI constexpr compare_three_way_result_t<_Tp, _Up>
operator<=>(const optional<_Tp>& __x, const _Up& __v) {
return __x.has_value() ? *__x <=> __v : strong_ordering::less;
}
# endif // _LIBCPP_STD_VER >= 20
template <class _Tp>
inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
enable_if_t< is_move_constructible_v<_Tp> && is_swappable_v<_Tp>, void >
swap(optional<_Tp>& __x, optional<_Tp>& __y) noexcept(noexcept(__x.swap(__y))) {
__x.swap(__y);
}
template <class _Tp>
_LIBCPP_HIDE_FROM_ABI constexpr optional<decay_t<_Tp>> make_optional(_Tp&& __v) {
return optional<decay_t<_Tp>>(std::forward<_Tp>(__v));
}
template <class _Tp, class... _Args>
_LIBCPP_HIDE_FROM_ABI constexpr optional<_Tp> make_optional(_Args&&... __args) {
return optional<_Tp>(in_place, std::forward<_Args>(__args)...);
}
template <class _Tp, class _Up, class... _Args>
_LIBCPP_HIDE_FROM_ABI constexpr optional<_Tp> make_optional(initializer_list<_Up> __il, _Args&&... __args) {
return optional<_Tp>(in_place, __il, std::forward<_Args>(__args)...);
}
template <class _Tp>
struct _LIBCPP_TEMPLATE_VIS hash< __enable_hash_helper<optional<_Tp>, remove_const_t<_Tp>> > {
# if _LIBCPP_STD_VER <= 17 || defined(_LIBCPP_ENABLE_CXX20_REMOVED_BINDER_TYPEDEFS)
_LIBCPP_DEPRECATED_IN_CXX17 typedef optional<_Tp> argument_type;
_LIBCPP_DEPRECATED_IN_CXX17 typedef size_t result_type;
# endif
_LIBCPP_HIDE_FROM_ABI size_t operator()(const optional<_Tp>& __opt) const {
return static_cast<bool>(__opt) ? hash<remove_const_t<_Tp>>()(*__opt) : 0;
}
};
_LIBCPP_END_NAMESPACE_STD
#endif // _LIBCPP_STD_VER >= 17
_LIBCPP_POP_MACROS
#if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES) && _LIBCPP_STD_VER <= 20
# include <atomic>
# include <climits>
# include <concepts>
# include <ctime>
# include <iterator>
# include <limits>
# include <memory>
# include <ratio>
# include <stdexcept>
# include <tuple>
# include <type_traits>
# include <typeinfo>
# include <utility>
# include <variant>
#endif
#endif // _LIBCPP_OPTIONAL