1009 lines
28 KiB
C++
1009 lines
28 KiB
C++
// <optional> -*- C++ -*-
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// Copyright (C) 2013-2017 Free Software Foundation, Inc.
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//
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// This file is part of the GNU ISO C++ Library. This library is free
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// software; you can redistribute it and/or modify it under the
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// terms of the GNU General Public License as published by the
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// Free Software Foundation; either version 3, or (at your option)
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// any later version.
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// Under Section 7 of GPL version 3, you are granted additional
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// permissions described in the GCC Runtime Library Exception, version
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// 3.1, as published by the Free Software Foundation.
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// You should have received a copy of the GNU General Public License and
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// a copy of the GCC Runtime Library Exception along with this program;
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// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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// <http://www.gnu.org/licenses/>.
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/** @file experimental/optional
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* This is a TS C++ Library header.
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*/
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#ifndef _GLIBCXX_EXPERIMENTAL_OPTIONAL
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#define _GLIBCXX_EXPERIMENTAL_OPTIONAL 1
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/**
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* @defgroup experimental Experimental
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*
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* Components specified by various Technical Specifications.
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*
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* As indicated by the std::experimental namespace and the header paths,
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* the contents of these Technical Specifications are experimental and not
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* part of the C++ standard. As such the interfaces and implementations may
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* change in the future, and there is <STRONG> no guarantee of compatibility
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* between different GCC releases </STRONG> for these features.
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*/
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#if __cplusplus <= 201103L
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# include <bits/c++14_warning.h>
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#else
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#include <utility>
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#include <type_traits>
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#include <stdexcept>
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#include <new>
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#include <initializer_list>
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#include <bits/functexcept.h>
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#include <bits/functional_hash.h>
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#include <bits/enable_special_members.h>
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#include <experimental/bits/lfts_config.h>
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namespace std _GLIBCXX_VISIBILITY(default)
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{
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namespace experimental
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{
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inline namespace fundamentals_v1
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{
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_GLIBCXX_BEGIN_NAMESPACE_VERSION
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/**
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* @defgroup optional Optional values
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* @ingroup experimental
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*
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* Class template for optional values and surrounding facilities, as
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* described in n3793 "A proposal to add a utility class to represent
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* optional objects (Revision 5)".
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*
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* @{
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*/
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#define __cpp_lib_experimental_optional 201411
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// All subsequent [X.Y.n] references are against n3793.
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// [X.Y.4]
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template<typename _Tp>
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class optional;
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// [X.Y.5]
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/// Tag type for in-place construction.
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struct in_place_t { };
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/// Tag for in-place construction.
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constexpr in_place_t in_place { };
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// [X.Y.6]
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/// Tag type to disengage optional objects.
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struct nullopt_t
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{
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// Do not user-declare default constructor at all for
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// optional_value = {} syntax to work.
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// nullopt_t() = delete;
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// Used for constructing nullopt.
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enum class _Construct { _Token };
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// Must be constexpr for nullopt_t to be literal.
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explicit constexpr nullopt_t(_Construct) { }
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};
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// [X.Y.6]
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/// Tag to disengage optional objects.
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constexpr nullopt_t nullopt { nullopt_t::_Construct::_Token };
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// [X.Y.7]
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/**
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* @brief Exception class thrown when a disengaged optional object is
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* dereferenced.
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* @ingroup exceptions
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*/
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class bad_optional_access : public logic_error
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{
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public:
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bad_optional_access() : logic_error("bad optional access") { }
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// XXX This constructor is non-standard. Should not be inline
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explicit bad_optional_access(const char* __arg) : logic_error(__arg) { }
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virtual ~bad_optional_access() noexcept = default;
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};
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void
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__throw_bad_optional_access(const char*)
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__attribute__((__noreturn__));
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// XXX Does not belong here.
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inline void
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__throw_bad_optional_access(const char* __s)
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{ _GLIBCXX_THROW_OR_ABORT(bad_optional_access(__s)); }
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#ifndef __cpp_lib_addressof_constexpr
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template<typename _Tp, typename = void>
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struct _Has_addressof_mem : std::false_type { };
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template<typename _Tp>
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struct _Has_addressof_mem<_Tp,
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__void_t<decltype( std::declval<const _Tp&>().operator&() )>
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>
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: std::true_type { };
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template<typename _Tp, typename = void>
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struct _Has_addressof_free : std::false_type { };
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template<typename _Tp>
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struct _Has_addressof_free<_Tp,
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__void_t<decltype( operator&(std::declval<const _Tp&>()) )>
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>
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: std::true_type { };
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/**
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* @brief Trait that detects the presence of an overloaded unary operator&.
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*
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* Practically speaking this detects the presence of such an operator when
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* called on a const-qualified lvalue (e.g.
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* declval<const _Tp&>().operator&()).
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*/
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template<typename _Tp>
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struct _Has_addressof
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: std::__or_<_Has_addressof_mem<_Tp>, _Has_addressof_free<_Tp>>::type
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{ };
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/**
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* @brief An overload that attempts to take the address of an lvalue as a
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* constant expression. Falls back to __addressof in the presence of an
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* overloaded addressof operator (unary operator&), in which case the call
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* will not be a constant expression.
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*/
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template<typename _Tp>
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constexpr
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enable_if_t<!_Has_addressof<_Tp>::value, _Tp*>
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__constexpr_addressof(_Tp& __t)
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{ return &__t; }
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/**
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* @brief Fallback overload that defers to __addressof.
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*/
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template<typename _Tp>
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inline
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enable_if_t<_Has_addressof<_Tp>::value, _Tp*>
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__constexpr_addressof(_Tp& __t)
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{ return std::__addressof(__t); }
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#endif // __cpp_lib_addressof_constexpr
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/**
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* @brief Class template that holds the necessary state for @ref optional
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* and that has the responsibility for construction and the special members.
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*
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* Such a separate base class template is necessary in order to
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* conditionally enable the special members (e.g. copy/move constructors).
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* Note that this means that @ref _Optional_base implements the
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* functionality for copy and move assignment, but not for converting
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* assignment.
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*
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* @see optional, _Enable_special_members
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*/
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template<typename _Tp, bool _ShouldProvideDestructor =
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!is_trivially_destructible<_Tp>::value>
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class _Optional_base
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{
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private:
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// Remove const to avoid prohibition of reusing object storage for
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// const-qualified types in [3.8/9]. This is strictly internal
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// and even optional itself is oblivious to it.
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using _Stored_type = remove_const_t<_Tp>;
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public:
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// [X.Y.4.1] Constructors.
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// Constructors for disengaged optionals.
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constexpr _Optional_base() noexcept
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: _M_empty{} { }
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constexpr _Optional_base(nullopt_t) noexcept
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: _Optional_base{} { }
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// Constructors for engaged optionals.
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template<typename... _Args>
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constexpr explicit _Optional_base(in_place_t, _Args&&... __args)
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: _M_payload(std::forward<_Args>(__args)...), _M_engaged(true) { }
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template<typename _Up, typename... _Args,
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enable_if_t<is_constructible<_Tp,
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initializer_list<_Up>&,
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_Args&&...>::value,
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int>...>
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constexpr explicit _Optional_base(in_place_t,
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initializer_list<_Up> __il,
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_Args&&... __args)
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: _M_payload(__il, std::forward<_Args>(__args)...),
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_M_engaged(true) { }
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// Copy and move constructors.
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_Optional_base(const _Optional_base& __other)
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{
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if (__other._M_engaged)
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this->_M_construct(__other._M_get());
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}
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_Optional_base(_Optional_base&& __other)
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noexcept(is_nothrow_move_constructible<_Tp>())
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{
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if (__other._M_engaged)
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this->_M_construct(std::move(__other._M_get()));
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}
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// [X.Y.4.3] (partly) Assignment.
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_Optional_base&
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operator=(const _Optional_base& __other)
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{
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if (this->_M_engaged && __other._M_engaged)
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this->_M_get() = __other._M_get();
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else
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{
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if (__other._M_engaged)
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this->_M_construct(__other._M_get());
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else
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this->_M_reset();
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}
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return *this;
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}
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_Optional_base&
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operator=(_Optional_base&& __other)
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noexcept(__and_<is_nothrow_move_constructible<_Tp>,
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is_nothrow_move_assignable<_Tp>>())
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{
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if (this->_M_engaged && __other._M_engaged)
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this->_M_get() = std::move(__other._M_get());
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else
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{
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if (__other._M_engaged)
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this->_M_construct(std::move(__other._M_get()));
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else
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this->_M_reset();
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}
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return *this;
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}
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// [X.Y.4.2] Destructor.
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~_Optional_base()
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{
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if (this->_M_engaged)
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this->_M_payload.~_Stored_type();
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}
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// The following functionality is also needed by optional, hence the
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// protected accessibility.
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protected:
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constexpr bool _M_is_engaged() const noexcept
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{ return this->_M_engaged; }
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// The _M_get operations have _M_engaged as a precondition.
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constexpr _Tp&
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_M_get() noexcept
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{ return _M_payload; }
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constexpr const _Tp&
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_M_get() const noexcept
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{ return _M_payload; }
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// The _M_construct operation has !_M_engaged as a precondition
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// while _M_destruct has _M_engaged as a precondition.
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template<typename... _Args>
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void
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_M_construct(_Args&&... __args)
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noexcept(is_nothrow_constructible<_Stored_type, _Args...>())
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{
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::new (std::__addressof(this->_M_payload))
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_Stored_type(std::forward<_Args>(__args)...);
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this->_M_engaged = true;
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}
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void
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_M_destruct()
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{
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this->_M_engaged = false;
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this->_M_payload.~_Stored_type();
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}
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// _M_reset is a 'safe' operation with no precondition.
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void
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_M_reset()
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{
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if (this->_M_engaged)
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this->_M_destruct();
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}
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private:
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struct _Empty_byte { };
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union {
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_Empty_byte _M_empty;
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_Stored_type _M_payload;
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};
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bool _M_engaged = false;
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};
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/// Partial specialization that is exactly identical to the primary template
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/// save for not providing a destructor, to fulfill triviality requirements.
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template<typename _Tp>
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class _Optional_base<_Tp, false>
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{
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private:
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using _Stored_type = remove_const_t<_Tp>;
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public:
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constexpr _Optional_base() noexcept
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: _M_empty{} { }
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constexpr _Optional_base(nullopt_t) noexcept
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: _Optional_base{} { }
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template<typename... _Args>
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constexpr explicit _Optional_base(in_place_t, _Args&&... __args)
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: _M_payload(std::forward<_Args>(__args)...), _M_engaged(true) { }
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template<typename _Up, typename... _Args,
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enable_if_t<is_constructible<_Tp,
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initializer_list<_Up>&,
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_Args&&...>::value,
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int>...>
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constexpr explicit _Optional_base(in_place_t,
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initializer_list<_Up> __il,
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_Args&&... __args)
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: _M_payload(__il, std::forward<_Args>(__args)...),
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_M_engaged(true) { }
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_Optional_base(const _Optional_base& __other)
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{
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if (__other._M_engaged)
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this->_M_construct(__other._M_get());
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}
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_Optional_base(_Optional_base&& __other)
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noexcept(is_nothrow_move_constructible<_Tp>())
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{
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if (__other._M_engaged)
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this->_M_construct(std::move(__other._M_get()));
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}
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_Optional_base&
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operator=(const _Optional_base& __other)
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{
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if (this->_M_engaged && __other._M_engaged)
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this->_M_get() = __other._M_get();
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else
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{
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if (__other._M_engaged)
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this->_M_construct(__other._M_get());
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else
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this->_M_reset();
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}
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return *this;
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}
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_Optional_base&
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operator=(_Optional_base&& __other)
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noexcept(__and_<is_nothrow_move_constructible<_Tp>,
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is_nothrow_move_assignable<_Tp>>())
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{
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if (this->_M_engaged && __other._M_engaged)
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this->_M_get() = std::move(__other._M_get());
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else
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{
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if (__other._M_engaged)
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this->_M_construct(std::move(__other._M_get()));
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else
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this->_M_reset();
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}
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return *this;
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}
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// Sole difference
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// ~_Optional_base() noexcept = default;
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protected:
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constexpr bool _M_is_engaged() const noexcept
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{ return this->_M_engaged; }
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_Tp&
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_M_get() noexcept
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{ return _M_payload; }
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constexpr const _Tp&
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_M_get() const noexcept
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{ return _M_payload; }
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template<typename... _Args>
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void
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_M_construct(_Args&&... __args)
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noexcept(is_nothrow_constructible<_Stored_type, _Args...>())
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{
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::new (std::__addressof(this->_M_payload))
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_Stored_type(std::forward<_Args>(__args)...);
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this->_M_engaged = true;
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}
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void
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_M_destruct()
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{
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this->_M_engaged = false;
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this->_M_payload.~_Stored_type();
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}
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void
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_M_reset()
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{
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if (this->_M_engaged)
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this->_M_destruct();
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}
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private:
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struct _Empty_byte { };
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union
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{
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_Empty_byte _M_empty;
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_Stored_type _M_payload;
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};
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bool _M_engaged = false;
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};
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template<typename _Tp>
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class optional;
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template<typename _Tp, typename _Up>
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using __converts_from_optional =
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__or_<is_constructible<_Tp, const optional<_Up>&>,
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is_constructible<_Tp, optional<_Up>&>,
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is_constructible<_Tp, const optional<_Up>&&>,
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is_constructible<_Tp, optional<_Up>&&>,
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is_convertible<const optional<_Up>&, _Tp>,
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is_convertible<optional<_Up>&, _Tp>,
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is_convertible<const optional<_Up>&&, _Tp>,
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is_convertible<optional<_Up>&&, _Tp>>;
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template<typename _Tp, typename _Up>
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using __assigns_from_optional =
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__or_<is_assignable<_Tp&, const optional<_Up>&>,
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is_assignable<_Tp&, optional<_Up>&>,
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is_assignable<_Tp&, const optional<_Up>&&>,
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is_assignable<_Tp&, optional<_Up>&&>>;
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/**
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* @brief Class template for optional values.
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*/
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template<typename _Tp>
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class optional
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: private _Optional_base<_Tp>,
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private _Enable_copy_move<
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// Copy constructor.
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is_copy_constructible<_Tp>::value,
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// Copy assignment.
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__and_<is_copy_constructible<_Tp>, is_copy_assignable<_Tp>>::value,
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// Move constructor.
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is_move_constructible<_Tp>::value,
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// Move assignment.
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__and_<is_move_constructible<_Tp>, is_move_assignable<_Tp>>::value,
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// Unique tag type.
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optional<_Tp>>
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{
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static_assert(__and_<__not_<is_same<remove_cv_t<_Tp>, nullopt_t>>,
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__not_<is_same<remove_cv_t<_Tp>, in_place_t>>,
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__not_<is_reference<_Tp>>>(),
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"Invalid instantiation of optional<T>");
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private:
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using _Base = _Optional_base<_Tp>;
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public:
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using value_type = _Tp;
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|
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// _Optional_base has the responsibility for construction.
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using _Base::_Base;
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|
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constexpr optional() = default;
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// Converting constructors for engaged optionals.
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template <typename _Up = _Tp,
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enable_if_t<__and_<
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__not_<is_same<optional<_Tp>, decay_t<_Up>>>,
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is_constructible<_Tp, _Up&&>,
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is_convertible<_Up&&, _Tp>
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>::value, bool> = true>
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constexpr optional(_Up&& __t)
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: _Base(in_place, std::forward<_Up>(__t)) { }
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template <typename _Up = _Tp,
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enable_if_t<__and_<
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__not_<is_same<optional<_Tp>, decay_t<_Up>>>,
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is_constructible<_Tp, _Up&&>,
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__not_<is_convertible<_Up&&, _Tp>>
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>::value, bool> = false>
|
|
explicit constexpr optional(_Up&& __t)
|
|
: _Base(in_place, std::forward<_Up>(__t)) { }
|
|
|
|
template <typename _Up,
|
|
enable_if_t<__and_<
|
|
__not_<is_same<_Tp, _Up>>,
|
|
is_constructible<_Tp, const _Up&>,
|
|
is_convertible<const _Up&, _Tp>,
|
|
__not_<__converts_from_optional<_Tp, _Up>>
|
|
>::value, bool> = true>
|
|
constexpr optional(const optional<_Up>& __t)
|
|
{
|
|
if (__t)
|
|
emplace(*__t);
|
|
}
|
|
|
|
template <typename _Up,
|
|
enable_if_t<__and_<
|
|
__not_<is_same<_Tp, _Up>>,
|
|
is_constructible<_Tp, const _Up&>,
|
|
__not_<is_convertible<const _Up&, _Tp>>,
|
|
__not_<__converts_from_optional<_Tp, _Up>>
|
|
>::value, bool> = false>
|
|
explicit constexpr optional(const optional<_Up>& __t)
|
|
{
|
|
if (__t)
|
|
emplace(*__t);
|
|
}
|
|
|
|
template <typename _Up,
|
|
enable_if_t<__and_<
|
|
__not_<is_same<_Tp, _Up>>,
|
|
is_constructible<_Tp, _Up&&>,
|
|
is_convertible<_Up&&, _Tp>,
|
|
__not_<__converts_from_optional<_Tp, _Up>>
|
|
>::value, bool> = true>
|
|
constexpr optional(optional<_Up>&& __t)
|
|
{
|
|
if (__t)
|
|
emplace(std::move(*__t));
|
|
}
|
|
|
|
template <typename _Up,
|
|
enable_if_t<__and_<
|
|
__not_<is_same<_Tp, _Up>>,
|
|
is_constructible<_Tp, _Up&&>,
|
|
__not_<is_convertible<_Up&&, _Tp>>,
|
|
__not_<__converts_from_optional<_Tp, _Up>>
|
|
>::value, bool> = false>
|
|
explicit constexpr optional(optional<_Up>&& __t)
|
|
{
|
|
if (__t)
|
|
emplace(std::move(*__t));
|
|
}
|
|
|
|
// [X.Y.4.3] (partly) Assignment.
|
|
optional&
|
|
operator=(nullopt_t) noexcept
|
|
{
|
|
this->_M_reset();
|
|
return *this;
|
|
}
|
|
|
|
template<typename _Up = _Tp>
|
|
enable_if_t<__and_<
|
|
__not_<is_same<optional<_Tp>, decay_t<_Up>>>,
|
|
is_constructible<_Tp, _Up>,
|
|
__not_<__and_<is_scalar<_Tp>,
|
|
is_same<_Tp, decay_t<_Up>>>>,
|
|
is_assignable<_Tp&, _Up>>::value,
|
|
optional&>
|
|
operator=(_Up&& __u)
|
|
{
|
|
if (this->_M_is_engaged())
|
|
this->_M_get() = std::forward<_Up>(__u);
|
|
else
|
|
this->_M_construct(std::forward<_Up>(__u));
|
|
|
|
return *this;
|
|
}
|
|
|
|
template<typename _Up>
|
|
enable_if_t<__and_<
|
|
__not_<is_same<_Tp, _Up>>,
|
|
is_constructible<_Tp, const _Up&>,
|
|
is_assignable<_Tp&, _Up>,
|
|
__not_<__converts_from_optional<_Tp, _Up>>,
|
|
__not_<__assigns_from_optional<_Tp, _Up>>
|
|
>::value,
|
|
optional&>
|
|
operator=(const optional<_Up>& __u)
|
|
{
|
|
if (__u)
|
|
{
|
|
if (this->_M_is_engaged())
|
|
this->_M_get() = *__u;
|
|
else
|
|
this->_M_construct(*__u);
|
|
}
|
|
else
|
|
{
|
|
this->_M_reset();
|
|
}
|
|
return *this;
|
|
}
|
|
|
|
template<typename _Up>
|
|
enable_if_t<__and_<
|
|
__not_<is_same<_Tp, _Up>>,
|
|
is_constructible<_Tp, _Up>,
|
|
is_assignable<_Tp&, _Up>,
|
|
__not_<__converts_from_optional<_Tp, _Up>>,
|
|
__not_<__assigns_from_optional<_Tp, _Up>>
|
|
>::value,
|
|
optional&>
|
|
operator=(optional<_Up>&& __u)
|
|
{
|
|
if (__u)
|
|
{
|
|
if (this->_M_is_engaged())
|
|
this->_M_get() = std::move(*__u);
|
|
else
|
|
this->_M_construct(std::move(*__u));
|
|
}
|
|
else
|
|
{
|
|
this->_M_reset();
|
|
}
|
|
|
|
return *this;
|
|
}
|
|
|
|
template<typename... _Args>
|
|
enable_if_t<is_constructible<_Tp, _Args&&...>::value>
|
|
emplace(_Args&&... __args)
|
|
{
|
|
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
|
|
{
|
|
#ifndef __cpp_lib_addressof_constexpr
|
|
return __constexpr_addressof(this->_M_get());
|
|
#else
|
|
return std::__addressof(this->_M_get());
|
|
#endif
|
|
}
|
|
|
|
_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
|