0,0 → 1,864 |
// <optional> -*- C++ -*- |
|
// Copyright (C) 2013-2015 Free Software Foundation, Inc. |
// |
// This file is part of the GNU ISO C++ Library. This library is free |
// software; you can redistribute it and/or modify it under the |
// terms of the GNU General Public License as published by the |
// Free Software Foundation; either version 3, or (at your option) |
// any later version. |
|
// This library is distributed in the hope that it will be useful, |
// but WITHOUT ANY WARRANTY; without even the implied warranty of |
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
// GNU General Public License for more details. |
|
// Under Section 7 of GPL version 3, you are granted additional |
// permissions described in the GCC Runtime Library Exception, version |
// 3.1, as published by the Free Software Foundation. |
|
// You should have received a copy of the GNU General Public License and |
// a copy of the GCC Runtime Library Exception along with this program; |
// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see |
// <http://www.gnu.org/licenses/>. |
|
/** @file experimental/optional |
* This is a TS C++ Library header. |
*/ |
|
#ifndef _GLIBCXX_EXPERIMENTAL_OPTIONAL |
#define _GLIBCXX_EXPERIMENTAL_OPTIONAL 1 |
|
/** |
* @defgroup experimental Experimental |
* |
* Components specified by various Technical Specifications. |
* |
* As indicated by the std::experimental namespace and the header paths, |
* the contents of these Technical Specifications are experimental and not |
* part of the C++ standard. As such the interfaces and implementations may |
* change in the future, and there is <STRONG> no guarantee of compatibility |
* between different GCC releases </STRONG> for these features. |
*/ |
|
#if __cplusplus <= 201103L |
# include <bits/c++14_warning.h> |
#else |
|
#include <utility> |
#include <type_traits> |
#include <stdexcept> |
#include <new> |
#include <initializer_list> |
#include <bits/functexcept.h> |
#include <bits/functional_hash.h> |
#include <bits/enable_special_members.h> |
|
namespace std _GLIBCXX_VISIBILITY(default) |
{ |
namespace experimental |
{ |
inline namespace fundamentals_v1 |
{ |
_GLIBCXX_BEGIN_NAMESPACE_VERSION |
|
/** |
* @defgroup optional Optional values |
* @ingroup experimental |
* |
* Class template for optional values and surrounding facilities, as |
* described in n3793 "A proposal to add a utility class to represent |
* optional objects (Revision 5)". |
* |
* @{ |
*/ |
|
#define __cpp_lib_experimental_optional 201411 |
|
// All subsequent [X.Y.n] references are against n3793. |
|
// [X.Y.4] |
template<typename _Tp> |
class optional; |
|
// [X.Y.5] |
/// Tag type for in-place construction. |
struct in_place_t { }; |
|
/// Tag for in-place construction. |
constexpr in_place_t in_place { }; |
|
// [X.Y.6] |
/// Tag type to disengage optional objects. |
struct nullopt_t |
{ |
// Do not user-declare default constructor at all for |
// optional_value = {} syntax to work. |
// nullopt_t() = delete; |
|
// Used for constructing nullopt. |
enum class _Construct { _Token }; |
|
// Must be constexpr for nullopt_t to be literal. |
explicit constexpr nullopt_t(_Construct) { } |
}; |
|
// [X.Y.6] |
/// Tag to disengage optional objects. |
constexpr nullopt_t nullopt { nullopt_t::_Construct::_Token }; |
|
// [X.Y.7] |
/** |
* @brief Exception class thrown when a disengaged optional object is |
* dereferenced. |
* @ingroup exceptions |
*/ |
class bad_optional_access : public logic_error |
{ |
public: |
bad_optional_access() : logic_error("bad optional access") { } |
|
// XXX This constructor is non-standard. Should not be inline |
explicit bad_optional_access(const char* __arg) : logic_error(__arg) { } |
|
virtual ~bad_optional_access() noexcept = default; |
}; |
|
void |
__throw_bad_optional_access(const char*) |
__attribute__((__noreturn__)); |
|
// XXX Does not belong here. |
inline void |
__throw_bad_optional_access(const char* __s) |
{ _GLIBCXX_THROW_OR_ABORT(bad_optional_access(__s)); } |
|
template<typename _Tp, typename = void> |
struct _Has_addressof_mem : std::false_type { }; |
|
template<typename _Tp> |
struct _Has_addressof_mem<_Tp, |
__void_t<decltype( std::declval<const _Tp&>().operator&() )> |
> |
: std::true_type { }; |
|
template<typename _Tp, typename = void> |
struct _Has_addressof_free : std::false_type { }; |
|
template<typename _Tp> |
struct _Has_addressof_free<_Tp, |
__void_t<decltype( operator&(std::declval<const _Tp&>()) )> |
> |
: std::true_type { }; |
|
/** |
* @brief Trait that detects the presence of an overloaded unary operator&. |
* |
* Practically speaking this detects the presence of such an operator when |
* called on a const-qualified lvalue (i.e. |
* declval<_Tp * const&>().operator&()). |
*/ |
template<typename _Tp> |
struct _Has_addressof |
: std::__or_<_Has_addressof_mem<_Tp>, _Has_addressof_free<_Tp>>::type |
{ }; |
|
/** |
* @brief 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. |
*/ |
template<typename _Tp, enable_if_t<!_Has_addressof<_Tp>::value, int>...> |
constexpr _Tp* __constexpr_addressof(_Tp& __t) |
{ return &__t; } |
|
/** |
* @brief Fallback overload that defers to __addressof. |
*/ |
template<typename _Tp, enable_if_t<_Has_addressof<_Tp>::value, int>...> |
inline _Tp* __constexpr_addressof(_Tp& __t) |
{ return std::__addressof(__t); } |
|
/** |
* @brief Class template that holds the necessary state for @ref optional |
* and that has the responsibility for construction and the special members. |
* |
* Such a separate base class template is necessary in order to |
* conditionally enable the special members (e.g. copy/move constructors). |
* Note that this means that @ref _Optional_base implements the |
* functionality for copy and move assignment, but not for converting |
* assignment. |
* |
* @see optional, _Enable_special_members |
*/ |
template<typename _Tp, bool _ShouldProvideDestructor = |
!is_trivially_destructible<_Tp>::value> |
class _Optional_base |
{ |
private: |
// Remove const to avoid prohibition of reusing object storage for |
// const-qualified types in [3.8/9]. This is strictly internal |
// and even optional itself is oblivious to it. |
using _Stored_type = remove_const_t<_Tp>; |
|
public: |
// [X.Y.4.1] Constructors. |
|
// Constructors for disengaged optionals. |
constexpr _Optional_base() noexcept |
: _M_empty{} { } |
|
constexpr _Optional_base(nullopt_t) noexcept |
: _Optional_base{} { } |
|
// Constructors for engaged optionals. |
constexpr _Optional_base(const _Tp& __t) |
: _M_payload(__t), _M_engaged(true) { } |
|
constexpr _Optional_base(_Tp&& __t) |
: _M_payload(std::move(__t)), _M_engaged(true) { } |
|
template<typename... _Args> |
constexpr explicit _Optional_base(in_place_t, _Args&&... __args) |
: _M_payload(std::forward<_Args>(__args)...), _M_engaged(true) { } |
|
template<typename _Up, typename... _Args, |
enable_if_t<is_constructible<_Tp, |
initializer_list<_Up>&, |
_Args&&...>::value, |
int>...> |
constexpr explicit _Optional_base(in_place_t, |
initializer_list<_Up> __il, |
_Args&&... __args) |
: _M_payload(__il, std::forward<_Args>(__args)...), |
_M_engaged(true) { } |
|
// Copy and move constructors. |
_Optional_base(const _Optional_base& __other) |
{ |
if (__other._M_engaged) |
this->_M_construct(__other._M_get()); |
} |
|
_Optional_base(_Optional_base&& __other) |
noexcept(is_nothrow_move_constructible<_Tp>()) |
{ |
if (__other._M_engaged) |
this->_M_construct(std::move(__other._M_get())); |
} |
|
// [X.Y.4.3] (partly) Assignment. |
_Optional_base& |
operator=(const _Optional_base& __other) |
{ |
if (this->_M_engaged && __other._M_engaged) |
this->_M_get() = __other._M_get(); |
else |
{ |
if (__other._M_engaged) |
this->_M_construct(__other._M_get()); |
else |
this->_M_reset(); |
} |
|
return *this; |
} |
|
_Optional_base& |
operator=(_Optional_base&& __other) |
noexcept(__and_<is_nothrow_move_constructible<_Tp>, |
is_nothrow_move_assignable<_Tp>>()) |
{ |
if (this->_M_engaged && __other._M_engaged) |
this->_M_get() = std::move(__other._M_get()); |
else |
{ |
if (__other._M_engaged) |
this->_M_construct(std::move(__other._M_get())); |
else |
this->_M_reset(); |
} |
return *this; |
} |
|
// [X.Y.4.2] Destructor. |
~_Optional_base() |
{ |
if (this->_M_engaged) |
this->_M_payload.~_Stored_type(); |
} |
|
// The following functionality is also needed by optional, hence the |
// protected accessibility. |
protected: |
constexpr bool _M_is_engaged() const noexcept |
{ return this->_M_engaged; } |
|
// The _M_get operations have _M_engaged as a precondition. |
constexpr _Tp& |
_M_get() noexcept |
{ return _M_payload; } |
|
constexpr const _Tp& |
_M_get() const noexcept |
{ return _M_payload; } |
|
// The _M_construct operation has !_M_engaged as a precondition |
// while _M_destruct has _M_engaged as a precondition. |
template<typename... _Args> |
void |
_M_construct(_Args&&... __args) |
noexcept(is_nothrow_constructible<_Stored_type, _Args...>()) |
{ |
::new (std::__addressof(this->_M_payload)) |
_Stored_type(std::forward<_Args>(__args)...); |
this->_M_engaged = true; |
} |
|
void |
_M_destruct() |
{ |
this->_M_engaged = false; |
this->_M_payload.~_Stored_type(); |
} |
|
// _M_reset is a 'safe' operation with no precondition. |
void |
_M_reset() |
{ |
if (this->_M_engaged) |
this->_M_destruct(); |
} |
|
private: |
struct _Empty_byte { }; |
union { |
_Empty_byte _M_empty; |
_Stored_type _M_payload; |
}; |
bool _M_engaged = false; |
}; |
|
/// Partial specialization that is exactly identical to the primary template |
/// save for not providing a destructor, to fulfill triviality requirements. |
template<typename _Tp> |
class _Optional_base<_Tp, false> |
{ |
private: |
using _Stored_type = remove_const_t<_Tp>; |
|
public: |
constexpr _Optional_base() noexcept |
: _M_empty{} { } |
|
constexpr _Optional_base(nullopt_t) noexcept |
: _Optional_base{} { } |
|
constexpr _Optional_base(const _Tp& __t) |
: _M_payload(__t), _M_engaged(true) { } |
|
constexpr _Optional_base(_Tp&& __t) |
: _M_payload(std::move(__t)), _M_engaged(true) { } |
|
template<typename... _Args> |
constexpr explicit _Optional_base(in_place_t, _Args&&... __args) |
: _M_payload(std::forward<_Args>(__args)...), _M_engaged(true) { } |
|
template<typename _Up, typename... _Args, |
enable_if_t<is_constructible<_Tp, |
initializer_list<_Up>&, |
_Args&&...>::value, |
int>...> |
constexpr explicit _Optional_base(in_place_t, |
initializer_list<_Up> __il, |
_Args&&... __args) |
: _M_payload(__il, std::forward<_Args>(__args)...), |
_M_engaged(true) { } |
|
_Optional_base(const _Optional_base& __other) |
{ |
if (__other._M_engaged) |
this->_M_construct(__other._M_get()); |
} |
|
_Optional_base(_Optional_base&& __other) |
noexcept(is_nothrow_move_constructible<_Tp>()) |
{ |
if (__other._M_engaged) |
this->_M_construct(std::move(__other._M_get())); |
} |
|
_Optional_base& |
operator=(const _Optional_base& __other) |
{ |
if (this->_M_engaged && __other._M_engaged) |
this->_M_get() = __other._M_get(); |
else |
{ |
if (__other._M_engaged) |
this->_M_construct(__other._M_get()); |
else |
this->_M_reset(); |
} |
return *this; |
} |
|
_Optional_base& |
operator=(_Optional_base&& __other) |
noexcept(__and_<is_nothrow_move_constructible<_Tp>, |
is_nothrow_move_assignable<_Tp>>()) |
{ |
if (this->_M_engaged && __other._M_engaged) |
this->_M_get() = std::move(__other._M_get()); |
else |
{ |
if (__other._M_engaged) |
this->_M_construct(std::move(__other._M_get())); |
else |
this->_M_reset(); |
} |
return *this; |
} |
|
// Sole difference |
// ~_Optional_base() noexcept = default; |
|
protected: |
constexpr bool _M_is_engaged() const noexcept |
{ return this->_M_engaged; } |
|
_Tp& |
_M_get() noexcept |
{ return _M_payload; } |
|
constexpr const _Tp& |
_M_get() const noexcept |
{ return _M_payload; } |
|
template<typename... _Args> |
void |
_M_construct(_Args&&... __args) |
noexcept(is_nothrow_constructible<_Stored_type, _Args...>()) |
{ |
::new (std::__addressof(this->_M_payload)) |
_Stored_type(std::forward<_Args>(__args)...); |
this->_M_engaged = true; |
} |
|
void |
_M_destruct() |
{ |
this->_M_engaged = false; |
this->_M_payload.~_Stored_type(); |
} |
|
void |
_M_reset() |
{ |
if (this->_M_engaged) |
this->_M_destruct(); |
} |
|
private: |
struct _Empty_byte { }; |
union |
{ |
_Empty_byte _M_empty; |
_Stored_type _M_payload; |
}; |
bool _M_engaged = false; |
}; |
|
/** |
* @brief Class template for optional values. |
*/ |
template<typename _Tp> |
class optional |
: private _Optional_base<_Tp>, |
private _Enable_copy_move< |
// Copy constructor. |
is_copy_constructible<_Tp>::value, |
// Copy assignment. |
__and_<is_copy_constructible<_Tp>, is_copy_assignable<_Tp>>::value, |
// Move constructor. |
is_move_constructible<_Tp>::value, |
// Move assignment. |
__and_<is_move_constructible<_Tp>, is_move_assignable<_Tp>>::value, |
// Unique tag type. |
optional<_Tp>> |
{ |
static_assert(__and_<__not_<is_same<remove_cv_t<_Tp>, nullopt_t>>, |
__not_<is_same<remove_cv_t<_Tp>, in_place_t>>, |
__not_<is_reference<_Tp>>>(), |
"Invalid instantiation of optional<T>"); |
|
private: |
using _Base = _Optional_base<_Tp>; |
|
public: |
using value_type = _Tp; |
|
// _Optional_base has the responsibility for construction. |
using _Base::_Base; |
|
// [X.Y.4.3] (partly) Assignment. |
optional& |
operator=(nullopt_t) noexcept |
{ |
this->_M_reset(); |
return *this; |
} |
|
template<typename _Up> |
enable_if_t<is_same<_Tp, decay_t<_Up>>::value, optional&> |
operator=(_Up&& __u) |
{ |
static_assert(__and_<is_constructible<_Tp, _Up>, |
is_assignable<_Tp&, _Up>>(), |
"Cannot assign to value type from argument"); |
|
if (this->_M_is_engaged()) |
this->_M_get() = std::forward<_Up>(__u); |
else |
this->_M_construct(std::forward<_Up>(__u)); |
|
return *this; |
} |
|
template<typename... _Args> |
void |
emplace(_Args&&... __args) |
{ |
static_assert(is_constructible<_Tp, _Args&&...>(), |
"Cannot emplace value type from arguments"); |
|
this->_M_reset(); |
this->_M_construct(std::forward<_Args>(__args)...); |
} |
|
template<typename _Up, typename... _Args> |
enable_if_t<is_constructible<_Tp, initializer_list<_Up>&, |
_Args&&...>::value> |
emplace(initializer_list<_Up> __il, _Args&&... __args) |
{ |
this->_M_reset(); |
this->_M_construct(__il, std::forward<_Args>(__args)...); |
} |
|
// [X.Y.4.2] Destructor is implicit, implemented in _Optional_base. |
|
// [X.Y.4.4] Swap. |
void |
swap(optional& __other) |
noexcept(is_nothrow_move_constructible<_Tp>() |
&& noexcept(swap(declval<_Tp&>(), declval<_Tp&>()))) |
{ |
using std::swap; |
|
if (this->_M_is_engaged() && __other._M_is_engaged()) |
swap(this->_M_get(), __other._M_get()); |
else if (this->_M_is_engaged()) |
{ |
__other._M_construct(std::move(this->_M_get())); |
this->_M_destruct(); |
} |
else if (__other._M_is_engaged()) |
{ |
this->_M_construct(std::move(__other._M_get())); |
__other._M_destruct(); |
} |
} |
|
// [X.Y.4.5] Observers. |
constexpr const _Tp* |
operator->() const |
{ return __constexpr_addressof(this->_M_get()); } |
|
_Tp* |
operator->() |
{ return std::__addressof(this->_M_get()); } |
|
constexpr const _Tp& |
operator*() const& |
{ return this->_M_get(); } |
|
constexpr _Tp& |
operator*()& |
{ return this->_M_get(); } |
|
constexpr _Tp&& |
operator*()&& |
{ return std::move(this->_M_get()); } |
|
constexpr const _Tp&& |
operator*() const&& |
{ return std::move(this->_M_get()); } |
|
constexpr explicit operator bool() const noexcept |
{ return this->_M_is_engaged(); } |
|
constexpr const _Tp& |
value() const& |
{ |
return this->_M_is_engaged() |
? this->_M_get() |
: (__throw_bad_optional_access("Attempt to access value of a " |
"disengaged optional object"), |
this->_M_get()); |
} |
|
constexpr _Tp& |
value()& |
{ |
return this->_M_is_engaged() |
? this->_M_get() |
: (__throw_bad_optional_access("Attempt to access value of a " |
"disengaged optional object"), |
this->_M_get()); |
} |
|
constexpr _Tp&& |
value()&& |
{ |
return this->_M_is_engaged() |
? std::move(this->_M_get()) |
: (__throw_bad_optional_access("Attempt to access value of a " |
"disengaged optional object"), |
std::move(this->_M_get())); |
} |
|
constexpr const _Tp&& |
value() const&& |
{ |
return this->_M_is_engaged() |
? std::move(this->_M_get()) |
: (__throw_bad_optional_access("Attempt to access value of a " |
"disengaged optional object"), |
std::move(this->_M_get())); |
} |
|
template<typename _Up> |
constexpr _Tp |
value_or(_Up&& __u) const& |
{ |
static_assert(__and_<is_copy_constructible<_Tp>, |
is_convertible<_Up&&, _Tp>>(), |
"Cannot return value"); |
|
return this->_M_is_engaged() |
? this->_M_get() |
: static_cast<_Tp>(std::forward<_Up>(__u)); |
} |
|
template<typename _Up> |
_Tp |
value_or(_Up&& __u) && |
{ |
static_assert(__and_<is_move_constructible<_Tp>, |
is_convertible<_Up&&, _Tp>>(), |
"Cannot return value" ); |
|
return this->_M_is_engaged() |
? std::move(this->_M_get()) |
: static_cast<_Tp>(std::forward<_Up>(__u)); |
} |
}; |
|
// [X.Y.8] Comparisons between optional values. |
template<typename _Tp> |
constexpr bool |
operator==(const optional<_Tp>& __lhs, const optional<_Tp>& __rhs) |
{ |
return static_cast<bool>(__lhs) == static_cast<bool>(__rhs) |
&& (!__lhs || *__lhs == *__rhs); |
} |
|
template<typename _Tp> |
constexpr bool |
operator!=(const optional<_Tp>& __lhs, const optional<_Tp>& __rhs) |
{ return !(__lhs == __rhs); } |
|
template<typename _Tp> |
constexpr bool |
operator<(const optional<_Tp>& __lhs, const optional<_Tp>& __rhs) |
{ |
return static_cast<bool>(__rhs) && (!__lhs || *__lhs < *__rhs); |
} |
|
template<typename _Tp> |
constexpr bool |
operator>(const optional<_Tp>& __lhs, const optional<_Tp>& __rhs) |
{ return __rhs < __lhs; } |
|
template<typename _Tp> |
constexpr bool |
operator<=(const optional<_Tp>& __lhs, const optional<_Tp>& __rhs) |
{ return !(__rhs < __lhs); } |
|
template<typename _Tp> |
constexpr bool |
operator>=(const optional<_Tp>& __lhs, const optional<_Tp>& __rhs) |
{ return !(__lhs < __rhs); } |
|
// [X.Y.9] Comparisons with nullopt. |
template<typename _Tp> |
constexpr bool |
operator==(const optional<_Tp>& __lhs, nullopt_t) noexcept |
{ return !__lhs; } |
|
template<typename _Tp> |
constexpr bool |
operator==(nullopt_t, const optional<_Tp>& __rhs) noexcept |
{ return !__rhs; } |
|
template<typename _Tp> |
constexpr bool |
operator!=(const optional<_Tp>& __lhs, nullopt_t) noexcept |
{ return static_cast<bool>(__lhs); } |
|
template<typename _Tp> |
constexpr bool |
operator!=(nullopt_t, const optional<_Tp>& __rhs) noexcept |
{ return static_cast<bool>(__rhs); } |
|
template<typename _Tp> |
constexpr bool |
operator<(const optional<_Tp>& /* __lhs */, nullopt_t) noexcept |
{ return false; } |
|
template<typename _Tp> |
constexpr bool |
operator<(nullopt_t, const optional<_Tp>& __rhs) noexcept |
{ return static_cast<bool>(__rhs); } |
|
template<typename _Tp> |
constexpr bool |
operator>(const optional<_Tp>& __lhs, nullopt_t) noexcept |
{ return static_cast<bool>(__lhs); } |
|
template<typename _Tp> |
constexpr bool |
operator>(nullopt_t, const optional<_Tp>& /* __rhs */) noexcept |
{ return false; } |
|
template<typename _Tp> |
constexpr bool |
operator<=(const optional<_Tp>& __lhs, nullopt_t) noexcept |
{ return !__lhs; } |
|
template<typename _Tp> |
constexpr bool |
operator<=(nullopt_t, const optional<_Tp>& /* __rhs */) noexcept |
{ return true; } |
|
template<typename _Tp> |
constexpr bool |
operator>=(const optional<_Tp>& /* __lhs */, nullopt_t) noexcept |
{ return true; } |
|
template<typename _Tp> |
constexpr bool |
operator>=(nullopt_t, const optional<_Tp>& __rhs) noexcept |
{ return !__rhs; } |
|
// [X.Y.10] Comparisons with value type. |
template<typename _Tp> |
constexpr bool |
operator==(const optional<_Tp>& __lhs, const _Tp& __rhs) |
{ return __lhs && *__lhs == __rhs; } |
|
template<typename _Tp> |
constexpr bool |
operator==(const _Tp& __lhs, const optional<_Tp>& __rhs) |
{ return __rhs && __lhs == *__rhs; } |
|
template<typename _Tp> |
constexpr bool |
operator!=(const optional<_Tp>& __lhs, _Tp const& __rhs) |
{ return !__lhs || !(*__lhs == __rhs); } |
|
template<typename _Tp> |
constexpr bool |
operator!=(const _Tp& __lhs, const optional<_Tp>& __rhs) |
{ return !__rhs || !(__lhs == *__rhs); } |
|
template<typename _Tp> |
constexpr bool |
operator<(const optional<_Tp>& __lhs, const _Tp& __rhs) |
{ return !__lhs || *__lhs < __rhs; } |
|
template<typename _Tp> |
constexpr bool |
operator<(const _Tp& __lhs, const optional<_Tp>& __rhs) |
{ return __rhs && __lhs < *__rhs; } |
|
template<typename _Tp> |
constexpr bool |
operator>(const optional<_Tp>& __lhs, const _Tp& __rhs) |
{ return __lhs && __rhs < *__lhs; } |
|
template<typename _Tp> |
constexpr bool |
operator>(const _Tp& __lhs, const optional<_Tp>& __rhs) |
{ return !__rhs || *__rhs < __lhs; } |
|
template<typename _Tp> |
constexpr bool |
operator<=(const optional<_Tp>& __lhs, const _Tp& __rhs) |
{ return !__lhs || !(__rhs < *__lhs); } |
|
template<typename _Tp> |
constexpr bool |
operator<=(const _Tp& __lhs, const optional<_Tp>& __rhs) |
{ return __rhs && !(*__rhs < __lhs); } |
|
template<typename _Tp> |
constexpr bool |
operator>=(const optional<_Tp>& __lhs, const _Tp& __rhs) |
{ return __lhs && !(*__lhs < __rhs); } |
|
template<typename _Tp> |
constexpr bool |
operator>=(const _Tp& __lhs, const optional<_Tp>& __rhs) |
{ return !__rhs || !(__lhs < *__rhs); } |
|
// [X.Y.11] |
template<typename _Tp> |
inline void |
swap(optional<_Tp>& __lhs, optional<_Tp>& __rhs) |
noexcept(noexcept(__lhs.swap(__rhs))) |
{ __lhs.swap(__rhs); } |
|
template<typename _Tp> |
constexpr optional<decay_t<_Tp>> |
make_optional(_Tp&& __t) |
{ return optional<decay_t<_Tp>> { std::forward<_Tp>(__t) }; } |
|
// @} group optional |
_GLIBCXX_END_NAMESPACE_VERSION |
} // namespace fundamentals_v1 |
} |
|
// [X.Y.12] |
template<typename _Tp> |
struct hash<experimental::optional<_Tp>> |
{ |
using result_type = size_t; |
using argument_type = experimental::optional<_Tp>; |
|
size_t |
operator()(const experimental::optional<_Tp>& __t) const |
noexcept(noexcept(hash<_Tp> {}(*__t))) |
{ |
// We pick an arbitrary hash for disengaged optionals which hopefully |
// usual values of _Tp won't typically hash to. |
constexpr size_t __magic_disengaged_hash = static_cast<size_t>(-3333); |
return __t ? hash<_Tp> {}(*__t) : __magic_disengaged_hash; |
} |
}; |
} |
|
#endif // C++14 |
|
#endif // _GLIBCXX_EXPERIMENTAL_OPTIONAL |