mirror of git://gcc.gnu.org/git/gcc.git
1587 lines
44 KiB
C++
1587 lines
44 KiB
C++
// <optional> -*- C++ -*-
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// Copyright (C) 2013-2019 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 include/optional
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* This is a Standard C++ Library header.
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*/
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#ifndef _GLIBCXX_OPTIONAL
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#define _GLIBCXX_OPTIONAL 1
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#pragma GCC system_header
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#if __cplusplus >= 201703L
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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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namespace std _GLIBCXX_VISIBILITY(default)
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{
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_GLIBCXX_BEGIN_NAMESPACE_VERSION
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/**
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* @addtogroup utilities
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* @{
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*/
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#define __cpp_lib_optional 201603
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template<typename _Tp>
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class optional;
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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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/// Tag to disengage optional objects.
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inline constexpr nullopt_t nullopt { nullopt_t::_Construct::_Token };
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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 exception
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{
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public:
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bad_optional_access() { }
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virtual const char* what() const noexcept override
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{ return "bad optional access"; }
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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()
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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()
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{ _GLIBCXX_THROW_OR_ABORT(bad_optional_access()); }
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// Payload for optionals with non-trivial destructor.
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template <typename _Tp,
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bool /*_HasTrivialDestructor*/ =
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is_trivially_destructible_v<_Tp>,
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bool /*_HasTrivialCopy */ =
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is_trivially_copy_assignable_v<_Tp>
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&& is_trivially_copy_constructible_v<_Tp>,
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bool /*_HasTrivialMove */ =
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is_trivially_move_assignable_v<_Tp>
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&& is_trivially_move_constructible_v<_Tp>>
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struct _Optional_payload
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{
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constexpr _Optional_payload() noexcept : _M_empty() { }
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template <typename... _Args>
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constexpr
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_Optional_payload(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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constexpr
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_Optional_payload(std::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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{ }
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constexpr
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_Optional_payload(bool __engaged, const _Optional_payload& __other)
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: _Optional_payload(__other)
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{ }
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constexpr
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_Optional_payload(bool __engaged, _Optional_payload&& __other)
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: _Optional_payload(std::move(__other))
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{ }
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constexpr
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_Optional_payload(const _Optional_payload& __other)
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{
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if (__other._M_engaged)
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this->_M_construct(__other._M_payload);
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}
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constexpr
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_Optional_payload(_Optional_payload&& __other)
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{
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if (__other._M_engaged)
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this->_M_construct(std::move(__other._M_payload));
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}
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constexpr
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_Optional_payload&
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operator=(const _Optional_payload& __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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constexpr
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_Optional_payload&
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operator=(_Optional_payload&& __other)
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noexcept(__and_v<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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using _Stored_type = remove_const_t<_Tp>;
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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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~_Optional_payload()
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{
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if (_M_engaged)
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_M_payload.~_Stored_type();
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}
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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_v<_Stored_type, _Args...>)
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{
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::new ((void *) 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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// 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 this->_M_payload; }
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constexpr const _Tp&
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_M_get() const noexcept
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{ return this->_M_payload; }
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// _M_reset is a 'safe' operation with no precondition.
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constexpr
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void
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_M_reset() noexcept
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{
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if (this->_M_engaged)
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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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}
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};
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// Payload for potentially-constexpr optionals.
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template <typename _Tp>
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struct _Optional_payload<_Tp, true, true, true>
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{
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constexpr _Optional_payload() noexcept
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: _M_empty(), _M_engaged(false) { }
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template<typename... _Args>
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constexpr
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_Optional_payload(in_place_t, _Args&&... __args)
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: _M_payload(std::forward<_Args>(__args)...), _M_engaged(true)
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{ }
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template<typename _Up, typename... _Args>
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constexpr
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_Optional_payload(std::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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{ }
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template <class _Up> struct __ctor_tag {};
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constexpr
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_Optional_payload(__ctor_tag<bool>, const _Tp& __other)
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: _M_payload(__other), _M_engaged(true)
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{ }
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constexpr _Optional_payload(__ctor_tag<void>) noexcept
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: _M_empty(), _M_engaged(false)
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{ }
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constexpr _Optional_payload(__ctor_tag<bool>, _Tp&& __other)
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: _M_payload(std::move(__other)), _M_engaged(true)
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{ }
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constexpr
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_Optional_payload(bool __engaged, const _Optional_payload& __other)
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: _Optional_payload(__engaged ?
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_Optional_payload(__ctor_tag<bool>{},
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__other._M_payload) :
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_Optional_payload(__ctor_tag<void>{}))
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{ }
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constexpr
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_Optional_payload(bool __engaged, _Optional_payload&& __other)
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: _Optional_payload(__engaged
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? _Optional_payload(__ctor_tag<bool>{},
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std::move(__other._M_payload))
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: _Optional_payload(__ctor_tag<void>{}))
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{ }
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using _Stored_type = remove_const_t<_Tp>;
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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;
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};
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// Payload for optionals with non-trivial copy assignment.
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template <typename _Tp>
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struct _Optional_payload<_Tp, true, false, true>
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{
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constexpr _Optional_payload() noexcept
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: _M_empty(), _M_engaged(false) { }
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template<typename... _Args>
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constexpr
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_Optional_payload(in_place_t, _Args&&... __args)
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: _M_payload(std::forward<_Args>(__args)...), _M_engaged(true)
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{ }
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template<typename _Up, typename... _Args>
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constexpr
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_Optional_payload(std::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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{ }
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template <class _Up> struct __ctor_tag {};
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constexpr _Optional_payload(__ctor_tag<bool>, const _Tp& __other)
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: _M_payload(__other),
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_M_engaged(true)
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{ }
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constexpr _Optional_payload(__ctor_tag<void>) noexcept
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: _M_empty(), _M_engaged(false)
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{ }
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constexpr _Optional_payload(__ctor_tag<bool>, _Tp&& __other)
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: _M_payload(std::move(__other)),
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_M_engaged(true)
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{ }
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constexpr
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_Optional_payload(bool __engaged, const _Optional_payload& __other)
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: _Optional_payload(__engaged ?
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_Optional_payload(__ctor_tag<bool>{},
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__other._M_payload) :
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_Optional_payload(__ctor_tag<void>{}))
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{ }
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constexpr
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_Optional_payload(bool __engaged, _Optional_payload&& __other)
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: _Optional_payload(__engaged
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? _Optional_payload(__ctor_tag<bool>{},
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std::move(__other._M_payload))
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: _Optional_payload(__ctor_tag<void>{}))
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{ }
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_Optional_payload(const _Optional_payload&) = default;
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_Optional_payload(_Optional_payload&&) = default;
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constexpr
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_Optional_payload&
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operator=(const _Optional_payload& __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_payload&
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operator=(_Optional_payload&& __other) = default;
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using _Stored_type = remove_const_t<_Tp>;
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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;
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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_v<_Stored_type, _Args...>)
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{
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::new ((void *) 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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// 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 this->_M_payload; }
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constexpr const _Tp&
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_M_get() const noexcept
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{ return this->_M_payload; }
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// _M_reset is a 'safe' operation with no precondition.
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constexpr
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void
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_M_reset() noexcept
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{
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if (this->_M_engaged)
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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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}
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};
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// Payload for optionals with non-trivial move assignment.
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template <typename _Tp>
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struct _Optional_payload<_Tp, true, true, false>
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{
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constexpr _Optional_payload() noexcept
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: _M_empty(), _M_engaged(false) { }
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template<typename... _Args>
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constexpr
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_Optional_payload(in_place_t, _Args&&... __args)
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: _M_payload(std::forward<_Args>(__args)...),
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_M_engaged(true)
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{ }
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template<typename _Up, typename... _Args>
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constexpr
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_Optional_payload(std::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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{ }
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template <class _Up> struct __ctor_tag {};
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constexpr
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_Optional_payload(__ctor_tag<bool>, const _Tp& __other)
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: _M_payload(__other),
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_M_engaged(true)
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{ }
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constexpr _Optional_payload(__ctor_tag<void>) noexcept
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: _M_empty(), _M_engaged(false)
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{ }
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constexpr _Optional_payload(__ctor_tag<bool>, _Tp&& __other)
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: _M_payload(std::move(__other)),
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_M_engaged(true)
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{ }
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constexpr
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_Optional_payload(bool __engaged, const _Optional_payload& __other)
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: _Optional_payload(__engaged ?
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_Optional_payload(__ctor_tag<bool>{},
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__other._M_payload) :
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_Optional_payload(__ctor_tag<void>{}))
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{ }
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constexpr
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_Optional_payload(bool __engaged, _Optional_payload&& __other)
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: _Optional_payload(__engaged
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? _Optional_payload(__ctor_tag<bool>{},
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std::move(__other._M_payload))
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: _Optional_payload(__ctor_tag<void>{}))
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{ }
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_Optional_payload(const _Optional_payload&) = default;
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_Optional_payload(_Optional_payload&&) = default;
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_Optional_payload&
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operator=(const _Optional_payload& __other) = default;
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constexpr
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_Optional_payload&
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operator=(_Optional_payload&& __other)
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noexcept(__and_v<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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using _Stored_type = remove_const_t<_Tp>;
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|
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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;
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|
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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_v<_Stored_type, _Args...>)
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{
|
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::new ((void *) 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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// 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 this->_M_payload; }
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|
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constexpr const _Tp&
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_M_get() const noexcept
|
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{ return this->_M_payload; }
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|
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// _M_reset is a 'safe' operation with no precondition.
|
|
constexpr
|
|
void
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_M_reset() noexcept
|
|
{
|
|
if (this->_M_engaged)
|
|
{
|
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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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}
|
|
};
|
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|
|
// Payload for optionals with non-trivial copy and move assignment.
|
|
template <typename _Tp>
|
|
struct _Optional_payload<_Tp, true, false, false>
|
|
{
|
|
constexpr _Optional_payload() noexcept
|
|
: _M_empty(), _M_engaged(false) {}
|
|
|
|
template<typename... _Args>
|
|
constexpr
|
|
_Optional_payload(in_place_t, _Args&&... __args)
|
|
: _M_payload(std::forward<_Args>(__args)...),
|
|
_M_engaged(true)
|
|
{ }
|
|
|
|
template<typename _Up, typename... _Args>
|
|
constexpr
|
|
_Optional_payload(std::initializer_list<_Up> __il,
|
|
_Args&&... __args)
|
|
: _M_payload(__il, std::forward<_Args>(__args)...),
|
|
_M_engaged(true)
|
|
{ }
|
|
|
|
template <class _Up> struct __ctor_tag {};
|
|
|
|
constexpr _Optional_payload(__ctor_tag<bool>, const _Tp& __other)
|
|
: _M_payload(__other),
|
|
_M_engaged(true)
|
|
{ }
|
|
|
|
constexpr _Optional_payload(__ctor_tag<void>) noexcept
|
|
: _M_empty(), _M_engaged(false)
|
|
{ }
|
|
|
|
constexpr _Optional_payload(__ctor_tag<bool>, _Tp&& __other)
|
|
: _M_payload(std::move(__other)),
|
|
_M_engaged(true)
|
|
{ }
|
|
|
|
constexpr
|
|
_Optional_payload(bool __engaged, const _Optional_payload& __other)
|
|
: _Optional_payload(__engaged ?
|
|
_Optional_payload(__ctor_tag<bool>{},
|
|
__other._M_payload) :
|
|
_Optional_payload(__ctor_tag<void>{}))
|
|
{ }
|
|
|
|
constexpr
|
|
_Optional_payload(bool __engaged, _Optional_payload&& __other)
|
|
: _Optional_payload(__engaged
|
|
? _Optional_payload(__ctor_tag<bool>{},
|
|
std::move(__other._M_payload))
|
|
: _Optional_payload(__ctor_tag<void>{}))
|
|
{ }
|
|
|
|
_Optional_payload(const _Optional_payload&) = default;
|
|
_Optional_payload(_Optional_payload&&) = default;
|
|
|
|
constexpr
|
|
_Optional_payload&
|
|
operator=(const _Optional_payload& __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;
|
|
}
|
|
|
|
constexpr
|
|
_Optional_payload&
|
|
operator=(_Optional_payload&& __other)
|
|
noexcept(__and_v<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;
|
|
}
|
|
|
|
using _Stored_type = remove_const_t<_Tp>;
|
|
|
|
struct _Empty_byte { };
|
|
|
|
union {
|
|
_Empty_byte _M_empty;
|
|
_Stored_type _M_payload;
|
|
};
|
|
bool _M_engaged;
|
|
|
|
template<typename... _Args>
|
|
constexpr
|
|
void
|
|
_M_construct(_Args&&... __args)
|
|
noexcept(is_nothrow_constructible_v<_Stored_type, _Args...>)
|
|
{
|
|
::new ((void *) std::__addressof(this->_M_payload))
|
|
_Stored_type(std::forward<_Args>(__args)...);
|
|
this->_M_engaged = true;
|
|
}
|
|
|
|
// The _M_get operations have _M_engaged as a precondition.
|
|
constexpr _Tp&
|
|
_M_get() noexcept
|
|
{ return this->_M_payload; }
|
|
|
|
constexpr const _Tp&
|
|
_M_get() const noexcept
|
|
{ return this->_M_payload; }
|
|
|
|
// _M_reset is a 'safe' operation with no precondition.
|
|
constexpr
|
|
void
|
|
_M_reset() noexcept
|
|
{
|
|
if (this->_M_engaged)
|
|
{
|
|
this->_M_engaged = false;
|
|
this->_M_payload.~_Stored_type();
|
|
}
|
|
}
|
|
};
|
|
|
|
template<typename _Tp, typename _Dp>
|
|
class _Optional_base_impl
|
|
{
|
|
protected:
|
|
using _Stored_type = remove_const_t<_Tp>;
|
|
|
|
// 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_v<_Stored_type, _Args...>)
|
|
{
|
|
::new
|
|
(std::__addressof(static_cast<_Dp*>(this)->_M_payload._M_payload))
|
|
_Stored_type(std::forward<_Args>(__args)...);
|
|
static_cast<_Dp*>(this)->_M_payload._M_engaged = true;
|
|
}
|
|
|
|
void
|
|
_M_destruct() noexcept
|
|
{
|
|
static_cast<_Dp*>(this)->_M_payload._M_engaged = false;
|
|
static_cast<_Dp*>(this)->_M_payload._M_payload.~_Stored_type();
|
|
}
|
|
|
|
// _M_reset is a 'safe' operation with no precondition.
|
|
constexpr
|
|
void
|
|
_M_reset() noexcept
|
|
{
|
|
if (static_cast<_Dp*>(this)->_M_payload._M_engaged)
|
|
static_cast<_Dp*>(this)->_M_destruct();
|
|
}
|
|
};
|
|
|
|
/**
|
|
* @brief Class template that takes care of copy/move constructors
|
|
of optional
|
|
*
|
|
* Such a separate base class template is necessary in order to
|
|
* conditionally make copy/move constructors trivial.
|
|
* @see optional, _Enable_special_members
|
|
*/
|
|
template<typename _Tp,
|
|
bool = is_trivially_copy_constructible_v<_Tp>,
|
|
bool = is_trivially_move_constructible_v<_Tp>>
|
|
class _Optional_base
|
|
// protected inheritance because optional needs to reach that base too
|
|
: protected _Optional_base_impl<_Tp, _Optional_base<_Tp>>
|
|
{
|
|
friend class _Optional_base_impl<_Tp, _Optional_base<_Tp>>;
|
|
|
|
public:
|
|
// Constructors for disengaged optionals.
|
|
constexpr _Optional_base() = default;
|
|
|
|
// Constructors for engaged optionals.
|
|
template<typename... _Args,
|
|
enable_if_t<is_constructible_v<_Tp, _Args&&...>, bool> = false>
|
|
constexpr explicit _Optional_base(in_place_t, _Args&&... __args)
|
|
: _M_payload(in_place,
|
|
std::forward<_Args>(__args)...) { }
|
|
|
|
template<typename _Up, typename... _Args,
|
|
enable_if_t<is_constructible_v<_Tp,
|
|
initializer_list<_Up>&,
|
|
_Args&&...>, bool> = false>
|
|
constexpr explicit _Optional_base(in_place_t,
|
|
initializer_list<_Up> __il,
|
|
_Args&&... __args)
|
|
: _M_payload(in_place,
|
|
__il, std::forward<_Args>(__args)...)
|
|
{ }
|
|
|
|
// Copy and move constructors.
|
|
constexpr _Optional_base(const _Optional_base& __other)
|
|
: _M_payload(__other._M_payload._M_engaged,
|
|
__other._M_payload)
|
|
{ }
|
|
|
|
constexpr _Optional_base(_Optional_base&& __other)
|
|
noexcept(is_nothrow_move_constructible_v<_Tp>)
|
|
: _M_payload(__other._M_payload._M_engaged,
|
|
std::move(__other._M_payload))
|
|
{ }
|
|
|
|
// Assignment operators.
|
|
_Optional_base& operator=(const _Optional_base&) = default;
|
|
_Optional_base& operator=(_Optional_base&&) = default;
|
|
|
|
protected:
|
|
|
|
constexpr bool _M_is_engaged() const noexcept
|
|
{ return this->_M_payload._M_engaged; }
|
|
|
|
// The _M_get operations have _M_engaged as a precondition.
|
|
constexpr _Tp&
|
|
_M_get() noexcept
|
|
{
|
|
__glibcxx_assert(this->_M_is_engaged());
|
|
return this->_M_payload._M_payload;
|
|
}
|
|
|
|
constexpr const _Tp&
|
|
_M_get() const noexcept
|
|
{
|
|
__glibcxx_assert(this->_M_is_engaged());
|
|
return this->_M_payload._M_payload;
|
|
}
|
|
|
|
private:
|
|
_Optional_payload<_Tp> _M_payload;
|
|
};
|
|
|
|
template<typename _Tp>
|
|
class _Optional_base<_Tp, false, true>
|
|
: protected _Optional_base_impl<_Tp, _Optional_base<_Tp>>
|
|
{
|
|
friend class _Optional_base_impl<_Tp, _Optional_base<_Tp>>;
|
|
public:
|
|
|
|
// Constructors for disengaged optionals.
|
|
constexpr _Optional_base() = default;
|
|
|
|
// Constructors for engaged optionals.
|
|
template<typename... _Args,
|
|
enable_if_t<is_constructible_v<_Tp, _Args&&...>, bool> = false>
|
|
constexpr explicit _Optional_base(in_place_t, _Args&&... __args)
|
|
: _M_payload(in_place,
|
|
std::forward<_Args>(__args)...) { }
|
|
|
|
template<typename _Up, typename... _Args,
|
|
enable_if_t<is_constructible_v<_Tp,
|
|
initializer_list<_Up>&,
|
|
_Args&&...>, bool> = false>
|
|
constexpr explicit _Optional_base(in_place_t,
|
|
initializer_list<_Up> __il,
|
|
_Args&&... __args)
|
|
: _M_payload(in_place,
|
|
__il, std::forward<_Args>(__args)...)
|
|
{ }
|
|
|
|
// Copy and move constructors.
|
|
constexpr _Optional_base(const _Optional_base& __other)
|
|
: _M_payload(__other._M_payload._M_engaged,
|
|
__other._M_payload)
|
|
{ }
|
|
|
|
constexpr _Optional_base(_Optional_base&& __other) = default;
|
|
|
|
// Assignment operators.
|
|
_Optional_base& operator=(const _Optional_base&) = default;
|
|
_Optional_base& operator=(_Optional_base&&) = default;
|
|
|
|
protected:
|
|
|
|
constexpr bool _M_is_engaged() const noexcept
|
|
{ return this->_M_payload._M_engaged; }
|
|
|
|
// The _M_get operations have _M_engaged as a precondition.
|
|
constexpr _Tp&
|
|
_M_get() noexcept
|
|
{
|
|
__glibcxx_assert(this->_M_is_engaged());
|
|
return this->_M_payload._M_payload;
|
|
}
|
|
|
|
constexpr const _Tp&
|
|
_M_get() const noexcept
|
|
{
|
|
__glibcxx_assert(this->_M_is_engaged());
|
|
return this->_M_payload._M_payload;
|
|
}
|
|
|
|
private:
|
|
_Optional_payload<_Tp> _M_payload;
|
|
};
|
|
|
|
template<typename _Tp>
|
|
class _Optional_base<_Tp, true, false>
|
|
: protected _Optional_base_impl<_Tp, _Optional_base<_Tp>>
|
|
{
|
|
friend class _Optional_base_impl<_Tp, _Optional_base<_Tp>>;
|
|
public:
|
|
|
|
// Constructors for disengaged optionals.
|
|
constexpr _Optional_base() = default;
|
|
|
|
// Constructors for engaged optionals.
|
|
template<typename... _Args,
|
|
enable_if_t<is_constructible_v<_Tp, _Args&&...>, bool> = false>
|
|
constexpr explicit _Optional_base(in_place_t, _Args&&... __args)
|
|
: _M_payload(in_place,
|
|
std::forward<_Args>(__args)...) { }
|
|
|
|
template<typename _Up, typename... _Args,
|
|
enable_if_t<is_constructible_v<_Tp,
|
|
initializer_list<_Up>&,
|
|
_Args&&...>, bool> = false>
|
|
constexpr explicit _Optional_base(in_place_t,
|
|
initializer_list<_Up> __il,
|
|
_Args&&... __args)
|
|
: _M_payload(in_place,
|
|
__il, std::forward<_Args>(__args)...)
|
|
{ }
|
|
|
|
// Copy and move constructors.
|
|
constexpr _Optional_base(const _Optional_base& __other) = default;
|
|
|
|
constexpr _Optional_base(_Optional_base&& __other)
|
|
noexcept(is_nothrow_move_constructible_v<_Tp>)
|
|
: _M_payload(__other._M_payload._M_engaged,
|
|
std::move(__other._M_payload))
|
|
{ }
|
|
|
|
// Assignment operators.
|
|
_Optional_base& operator=(const _Optional_base&) = default;
|
|
_Optional_base& operator=(_Optional_base&&) = default;
|
|
|
|
protected:
|
|
|
|
constexpr bool _M_is_engaged() const noexcept
|
|
{ return this->_M_payload._M_engaged; }
|
|
|
|
// The _M_get operations have _M_engaged as a precondition.
|
|
constexpr _Tp&
|
|
_M_get() noexcept
|
|
{
|
|
__glibcxx_assert(this->_M_is_engaged());
|
|
return this->_M_payload._M_payload;
|
|
}
|
|
|
|
constexpr const _Tp&
|
|
_M_get() const noexcept
|
|
{
|
|
__glibcxx_assert(this->_M_is_engaged());
|
|
return this->_M_payload._M_payload;
|
|
}
|
|
|
|
private:
|
|
_Optional_payload<_Tp> _M_payload;
|
|
};
|
|
|
|
template<typename _Tp>
|
|
class _Optional_base<_Tp, true, true>
|
|
: protected _Optional_base_impl<_Tp, _Optional_base<_Tp>>
|
|
{
|
|
friend class _Optional_base_impl<_Tp, _Optional_base<_Tp>>;
|
|
public:
|
|
|
|
// Constructors for disengaged optionals.
|
|
constexpr _Optional_base() = default;
|
|
|
|
// Constructors for engaged optionals.
|
|
template<typename... _Args,
|
|
enable_if_t<is_constructible_v<_Tp, _Args&&...>, bool> = false>
|
|
constexpr explicit _Optional_base(in_place_t, _Args&&... __args)
|
|
: _M_payload(in_place,
|
|
std::forward<_Args>(__args)...) { }
|
|
|
|
template<typename _Up, typename... _Args,
|
|
enable_if_t<is_constructible_v<_Tp,
|
|
initializer_list<_Up>&,
|
|
_Args&&...>, bool> = false>
|
|
constexpr explicit _Optional_base(in_place_t,
|
|
initializer_list<_Up> __il,
|
|
_Args&&... __args)
|
|
: _M_payload(in_place,
|
|
__il, std::forward<_Args>(__args)...)
|
|
{ }
|
|
|
|
// Copy and move constructors.
|
|
constexpr _Optional_base(const _Optional_base& __other) = default;
|
|
constexpr _Optional_base(_Optional_base&& __other) = default;
|
|
|
|
// Assignment operators.
|
|
_Optional_base& operator=(const _Optional_base&) = default;
|
|
_Optional_base& operator=(_Optional_base&&) = default;
|
|
|
|
protected:
|
|
|
|
constexpr bool _M_is_engaged() const noexcept
|
|
{ return this->_M_payload._M_engaged; }
|
|
|
|
// The _M_get operations have _M_engaged as a precondition.
|
|
constexpr _Tp&
|
|
_M_get() noexcept
|
|
{
|
|
__glibcxx_assert(this->_M_is_engaged());
|
|
return this->_M_payload._M_payload;
|
|
}
|
|
|
|
constexpr const _Tp&
|
|
_M_get() const noexcept
|
|
{
|
|
__glibcxx_assert(this->_M_is_engaged());
|
|
return this->_M_payload._M_payload;
|
|
}
|
|
|
|
private:
|
|
_Optional_payload<_Tp> _M_payload;
|
|
};
|
|
|
|
template<typename _Tp>
|
|
class optional;
|
|
|
|
template<typename _Tp, typename _Up>
|
|
using __converts_from_optional =
|
|
__or_<is_constructible<_Tp, const optional<_Up>&>,
|
|
is_constructible<_Tp, optional<_Up>&>,
|
|
is_constructible<_Tp, const optional<_Up>&&>,
|
|
is_constructible<_Tp, optional<_Up>&&>,
|
|
is_convertible<const optional<_Up>&, _Tp>,
|
|
is_convertible<optional<_Up>&, _Tp>,
|
|
is_convertible<const optional<_Up>&&, _Tp>,
|
|
is_convertible<optional<_Up>&&, _Tp>>;
|
|
|
|
template<typename _Tp, typename _Up>
|
|
using __assigns_from_optional =
|
|
__or_<is_assignable<_Tp&, const optional<_Up>&>,
|
|
is_assignable<_Tp&, optional<_Up>&>,
|
|
is_assignable<_Tp&, const optional<_Up>&&>,
|
|
is_assignable<_Tp&, optional<_Up>&&>>;
|
|
|
|
/**
|
|
* @brief Class template for optional values.
|
|
*/
|
|
template<typename _Tp>
|
|
class optional
|
|
: private _Optional_base<_Tp>,
|
|
private _Enable_copy_move<
|
|
// Copy constructor.
|
|
is_copy_constructible_v<_Tp>,
|
|
// Copy assignment.
|
|
__and_v<is_copy_constructible<_Tp>, is_copy_assignable<_Tp>>,
|
|
// Move constructor.
|
|
is_move_constructible_v<_Tp>,
|
|
// Move assignment.
|
|
__and_v<is_move_constructible<_Tp>, is_move_assignable<_Tp>>,
|
|
// Unique tag type.
|
|
optional<_Tp>>
|
|
{
|
|
static_assert(!is_same_v<remove_cv_t<_Tp>, nullopt_t>);
|
|
static_assert(!is_same_v<remove_cv_t<_Tp>, in_place_t>);
|
|
static_assert(!is_reference_v<_Tp>);
|
|
|
|
private:
|
|
using _Base = _Optional_base<_Tp>;
|
|
|
|
// SFINAE helpers
|
|
template<typename _Up>
|
|
using __not_self = __not_<is_same<optional, __remove_cvref_t<_Up>>>;
|
|
template<typename _Up>
|
|
using __not_tag = __not_<is_same<in_place_t, __remove_cvref_t<_Up>>>;
|
|
template<typename... _Cond>
|
|
using _Requires = enable_if_t<__and_v<_Cond...>, bool>;
|
|
|
|
public:
|
|
using value_type = _Tp;
|
|
|
|
constexpr optional() = default;
|
|
|
|
constexpr optional(nullopt_t) noexcept { }
|
|
|
|
// Converting constructors for engaged optionals.
|
|
template<typename _Up = _Tp,
|
|
_Requires<__not_self<_Up>, __not_tag<_Up>,
|
|
is_constructible<_Tp, _Up&&>,
|
|
is_convertible<_Up&&, _Tp>> = true>
|
|
constexpr
|
|
optional(_Up&& __t)
|
|
: _Base(std::in_place, std::forward<_Up>(__t)) { }
|
|
|
|
template<typename _Up = _Tp,
|
|
_Requires<__not_self<_Up>, __not_tag<_Up>,
|
|
is_constructible<_Tp, _Up&&>,
|
|
__not_<is_convertible<_Up&&, _Tp>>> = false>
|
|
explicit constexpr
|
|
optional(_Up&& __t)
|
|
: _Base(std::in_place, std::forward<_Up>(__t)) { }
|
|
|
|
template<typename _Up,
|
|
_Requires<__not_<is_same<_Tp, _Up>>,
|
|
is_constructible<_Tp, const _Up&>,
|
|
is_convertible<const _Up&, _Tp>,
|
|
__not_<__converts_from_optional<_Tp, _Up>>> = true>
|
|
constexpr
|
|
optional(const optional<_Up>& __t)
|
|
{
|
|
if (__t)
|
|
emplace(*__t);
|
|
}
|
|
|
|
template<typename _Up,
|
|
_Requires<__not_<is_same<_Tp, _Up>>,
|
|
is_constructible<_Tp, const _Up&>,
|
|
__not_<is_convertible<const _Up&, _Tp>>,
|
|
__not_<__converts_from_optional<_Tp, _Up>>> = false>
|
|
explicit constexpr
|
|
optional(const optional<_Up>& __t)
|
|
{
|
|
if (__t)
|
|
emplace(*__t);
|
|
}
|
|
|
|
template <typename _Up,
|
|
_Requires<__not_<is_same<_Tp, _Up>>,
|
|
is_constructible<_Tp, _Up&&>,
|
|
is_convertible<_Up&&, _Tp>,
|
|
__not_<__converts_from_optional<_Tp, _Up>>> = true>
|
|
constexpr
|
|
optional(optional<_Up>&& __t)
|
|
{
|
|
if (__t)
|
|
emplace(std::move(*__t));
|
|
}
|
|
|
|
template <typename _Up,
|
|
_Requires<__not_<is_same<_Tp, _Up>>,
|
|
is_constructible<_Tp, _Up&&>,
|
|
__not_<is_convertible<_Up&&, _Tp>>,
|
|
__not_<__converts_from_optional<_Tp, _Up>>> = false>
|
|
explicit constexpr
|
|
optional(optional<_Up>&& __t)
|
|
{
|
|
if (__t)
|
|
emplace(std::move(*__t));
|
|
}
|
|
|
|
template<typename... _Args,
|
|
_Requires<is_constructible<_Tp, _Args&&...>> = false>
|
|
explicit constexpr
|
|
optional(in_place_t, _Args&&... __args)
|
|
: _Base(std::in_place, std::forward<_Args>(__args)...) { }
|
|
|
|
template<typename _Up, typename... _Args,
|
|
_Requires<is_constructible<_Tp,
|
|
initializer_list<_Up>&,
|
|
_Args&&...>> = false>
|
|
explicit constexpr
|
|
optional(in_place_t, initializer_list<_Up> __il, _Args&&... __args)
|
|
: _Base(std::in_place, __il, std::forward<_Args>(__args)...) { }
|
|
|
|
// Assignment operators.
|
|
optional&
|
|
operator=(nullopt_t) noexcept
|
|
{
|
|
this->_M_reset();
|
|
return *this;
|
|
}
|
|
|
|
template<typename _Up = _Tp>
|
|
enable_if_t<__and_v<__not_self<_Up>,
|
|
__not_<__and_<is_scalar<_Tp>,
|
|
is_same<_Tp, decay_t<_Up>>>>,
|
|
is_constructible<_Tp, _Up>,
|
|
is_assignable<_Tp&, _Up>>,
|
|
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_v<__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>>>,
|
|
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_v<__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>>>,
|
|
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_v<_Tp, _Args&&...>, _Tp&>
|
|
emplace(_Args&&... __args)
|
|
{
|
|
this->_M_reset();
|
|
this->_M_construct(std::forward<_Args>(__args)...);
|
|
return this->_M_get();
|
|
}
|
|
|
|
template<typename _Up, typename... _Args>
|
|
enable_if_t<is_constructible_v<_Tp, initializer_list<_Up>&,
|
|
_Args&&...>, _Tp&>
|
|
emplace(initializer_list<_Up> __il, _Args&&... __args)
|
|
{
|
|
this->_M_reset();
|
|
this->_M_construct(__il, std::forward<_Args>(__args)...);
|
|
return this->_M_get();
|
|
}
|
|
|
|
// Destructor is implicit, implemented in _Optional_base.
|
|
|
|
// Swap.
|
|
void
|
|
swap(optional& __other)
|
|
noexcept(is_nothrow_move_constructible_v<_Tp>
|
|
&& is_nothrow_swappable_v<_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();
|
|
}
|
|
}
|
|
|
|
// Observers.
|
|
constexpr const _Tp*
|
|
operator->() const
|
|
{ return std::__addressof(this->_M_get()); }
|
|
|
|
constexpr
|
|
_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 bool has_value() const noexcept
|
|
{ return this->_M_is_engaged(); }
|
|
|
|
constexpr const _Tp&
|
|
value() const&
|
|
{
|
|
return this->_M_is_engaged()
|
|
? this->_M_get()
|
|
: (__throw_bad_optional_access(),
|
|
this->_M_get());
|
|
}
|
|
|
|
constexpr _Tp&
|
|
value()&
|
|
{
|
|
return this->_M_is_engaged()
|
|
? this->_M_get()
|
|
: (__throw_bad_optional_access(),
|
|
this->_M_get());
|
|
}
|
|
|
|
constexpr _Tp&&
|
|
value()&&
|
|
{
|
|
return this->_M_is_engaged()
|
|
? std::move(this->_M_get())
|
|
: (__throw_bad_optional_access(),
|
|
std::move(this->_M_get()));
|
|
}
|
|
|
|
constexpr const _Tp&&
|
|
value() const&&
|
|
{
|
|
return this->_M_is_engaged()
|
|
? std::move(this->_M_get())
|
|
: (__throw_bad_optional_access(),
|
|
std::move(this->_M_get()));
|
|
}
|
|
|
|
template<typename _Up>
|
|
constexpr _Tp
|
|
value_or(_Up&& __u) const&
|
|
{
|
|
static_assert(is_copy_constructible_v<_Tp>);
|
|
static_assert(is_convertible_v<_Up&&, _Tp>);
|
|
|
|
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(is_move_constructible_v<_Tp>);
|
|
static_assert(is_convertible_v<_Up&&, _Tp>);
|
|
|
|
return this->_M_is_engaged()
|
|
? std::move(this->_M_get())
|
|
: static_cast<_Tp>(std::forward<_Up>(__u));
|
|
}
|
|
|
|
void reset() noexcept { this->_M_reset(); }
|
|
};
|
|
|
|
template<typename _Tp>
|
|
using __optional_relop_t =
|
|
enable_if_t<is_convertible<_Tp, bool>::value, bool>;
|
|
|
|
// Comparisons between optional values.
|
|
template<typename _Tp, typename _Up>
|
|
constexpr auto
|
|
operator==(const optional<_Tp>& __lhs, const optional<_Up>& __rhs)
|
|
-> __optional_relop_t<decltype(declval<_Tp>() == declval<_Up>())>
|
|
{
|
|
return static_cast<bool>(__lhs) == static_cast<bool>(__rhs)
|
|
&& (!__lhs || *__lhs == *__rhs);
|
|
}
|
|
|
|
template<typename _Tp, typename _Up>
|
|
constexpr auto
|
|
operator!=(const optional<_Tp>& __lhs, const optional<_Up>& __rhs)
|
|
-> __optional_relop_t<decltype(declval<_Tp>() != declval<_Up>())>
|
|
{
|
|
return static_cast<bool>(__lhs) != static_cast<bool>(__rhs)
|
|
|| (static_cast<bool>(__lhs) && *__lhs != *__rhs);
|
|
}
|
|
|
|
template<typename _Tp, typename _Up>
|
|
constexpr auto
|
|
operator<(const optional<_Tp>& __lhs, const optional<_Up>& __rhs)
|
|
-> __optional_relop_t<decltype(declval<_Tp>() < declval<_Up>())>
|
|
{
|
|
return static_cast<bool>(__rhs) && (!__lhs || *__lhs < *__rhs);
|
|
}
|
|
|
|
template<typename _Tp, typename _Up>
|
|
constexpr auto
|
|
operator>(const optional<_Tp>& __lhs, const optional<_Up>& __rhs)
|
|
-> __optional_relop_t<decltype(declval<_Tp>() > declval<_Up>())>
|
|
{
|
|
return static_cast<bool>(__lhs) && (!__rhs || *__lhs > *__rhs);
|
|
}
|
|
|
|
template<typename _Tp, typename _Up>
|
|
constexpr auto
|
|
operator<=(const optional<_Tp>& __lhs, const optional<_Up>& __rhs)
|
|
-> __optional_relop_t<decltype(declval<_Tp>() <= declval<_Up>())>
|
|
{
|
|
return !__lhs || (static_cast<bool>(__rhs) && *__lhs <= *__rhs);
|
|
}
|
|
|
|
template<typename _Tp, typename _Up>
|
|
constexpr auto
|
|
operator>=(const optional<_Tp>& __lhs, const optional<_Up>& __rhs)
|
|
-> __optional_relop_t<decltype(declval<_Tp>() >= declval<_Up>())>
|
|
{
|
|
return !__rhs || (static_cast<bool>(__lhs) && *__lhs >= *__rhs);
|
|
}
|
|
|
|
// 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; }
|
|
|
|
// Comparisons with value type.
|
|
template<typename _Tp, typename _Up>
|
|
constexpr auto
|
|
operator==(const optional<_Tp>& __lhs, const _Up& __rhs)
|
|
-> __optional_relop_t<decltype(declval<_Tp>() == declval<_Up>())>
|
|
{ return __lhs && *__lhs == __rhs; }
|
|
|
|
template<typename _Tp, typename _Up>
|
|
constexpr auto
|
|
operator==(const _Up& __lhs, const optional<_Tp>& __rhs)
|
|
-> __optional_relop_t<decltype(declval<_Up>() == declval<_Tp>())>
|
|
{ return __rhs && __lhs == *__rhs; }
|
|
|
|
template<typename _Tp, typename _Up>
|
|
constexpr auto
|
|
operator!=(const optional<_Tp>& __lhs, const _Up& __rhs)
|
|
-> __optional_relop_t<decltype(declval<_Tp>() != declval<_Up>())>
|
|
{ return !__lhs || *__lhs != __rhs; }
|
|
|
|
template<typename _Tp, typename _Up>
|
|
constexpr auto
|
|
operator!=(const _Up& __lhs, const optional<_Tp>& __rhs)
|
|
-> __optional_relop_t<decltype(declval<_Up>() != declval<_Tp>())>
|
|
{ return !__rhs || __lhs != *__rhs; }
|
|
|
|
template<typename _Tp, typename _Up>
|
|
constexpr auto
|
|
operator<(const optional<_Tp>& __lhs, const _Up& __rhs)
|
|
-> __optional_relop_t<decltype(declval<_Tp>() < declval<_Up>())>
|
|
{ return !__lhs || *__lhs < __rhs; }
|
|
|
|
template<typename _Tp, typename _Up>
|
|
constexpr auto
|
|
operator<(const _Up& __lhs, const optional<_Tp>& __rhs)
|
|
-> __optional_relop_t<decltype(declval<_Up>() < declval<_Tp>())>
|
|
{ return __rhs && __lhs < *__rhs; }
|
|
|
|
template<typename _Tp, typename _Up>
|
|
constexpr auto
|
|
operator>(const optional<_Tp>& __lhs, const _Up& __rhs)
|
|
-> __optional_relop_t<decltype(declval<_Tp>() > declval<_Up>())>
|
|
{ return __lhs && *__lhs > __rhs; }
|
|
|
|
template<typename _Tp, typename _Up>
|
|
constexpr auto
|
|
operator>(const _Up& __lhs, const optional<_Tp>& __rhs)
|
|
-> __optional_relop_t<decltype(declval<_Up>() > declval<_Tp>())>
|
|
{ return !__rhs || __lhs > *__rhs; }
|
|
|
|
template<typename _Tp, typename _Up>
|
|
constexpr auto
|
|
operator<=(const optional<_Tp>& __lhs, const _Up& __rhs)
|
|
-> __optional_relop_t<decltype(declval<_Tp>() <= declval<_Up>())>
|
|
{ return !__lhs || *__lhs <= __rhs; }
|
|
|
|
template<typename _Tp, typename _Up>
|
|
constexpr auto
|
|
operator<=(const _Up& __lhs, const optional<_Tp>& __rhs)
|
|
-> __optional_relop_t<decltype(declval<_Up>() <= declval<_Tp>())>
|
|
{ return __rhs && __lhs <= *__rhs; }
|
|
|
|
template<typename _Tp, typename _Up>
|
|
constexpr auto
|
|
operator>=(const optional<_Tp>& __lhs, const _Up& __rhs)
|
|
-> __optional_relop_t<decltype(declval<_Tp>() >= declval<_Up>())>
|
|
{ return __lhs && *__lhs >= __rhs; }
|
|
|
|
template<typename _Tp, typename _Up>
|
|
constexpr auto
|
|
operator>=(const _Up& __lhs, const optional<_Tp>& __rhs)
|
|
-> __optional_relop_t<decltype(declval<_Up>() >= declval<_Tp>())>
|
|
{ return !__rhs || __lhs >= *__rhs; }
|
|
|
|
// Swap and creation functions.
|
|
|
|
// _GLIBCXX_RESOLVE_LIB_DEFECTS
|
|
// 2748. swappable traits for optionals
|
|
template<typename _Tp>
|
|
inline enable_if_t<is_move_constructible_v<_Tp> && is_swappable_v<_Tp>>
|
|
swap(optional<_Tp>& __lhs, optional<_Tp>& __rhs)
|
|
noexcept(noexcept(__lhs.swap(__rhs)))
|
|
{ __lhs.swap(__rhs); }
|
|
|
|
template<typename _Tp>
|
|
enable_if_t<!(is_move_constructible_v<_Tp> && is_swappable_v<_Tp>)>
|
|
swap(optional<_Tp>&, optional<_Tp>&) = delete;
|
|
|
|
template<typename _Tp>
|
|
constexpr optional<decay_t<_Tp>>
|
|
make_optional(_Tp&& __t)
|
|
{ return optional<decay_t<_Tp>> { std::forward<_Tp>(__t) }; }
|
|
|
|
template<typename _Tp, typename ..._Args>
|
|
constexpr optional<_Tp>
|
|
make_optional(_Args&&... __args)
|
|
{ return optional<_Tp> { in_place, std::forward<_Args>(__args)... }; }
|
|
|
|
template<typename _Tp, typename _Up, typename ..._Args>
|
|
constexpr optional<_Tp>
|
|
make_optional(initializer_list<_Up> __il, _Args&&... __args)
|
|
{ return optional<_Tp> { in_place, __il, std::forward<_Args>(__args)... }; }
|
|
|
|
// Hash.
|
|
|
|
template<typename _Tp, typename _Up = remove_const_t<_Tp>,
|
|
bool = __poison_hash<_Up>::__enable_hash_call>
|
|
struct __optional_hash_call_base
|
|
{
|
|
size_t
|
|
operator()(const optional<_Tp>& __t) const
|
|
noexcept(noexcept(hash<_Up>{}(*__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<_Up>{}(*__t) : __magic_disengaged_hash;
|
|
}
|
|
};
|
|
|
|
template<typename _Tp, typename _Up>
|
|
struct __optional_hash_call_base<_Tp, _Up, false> {};
|
|
|
|
template<typename _Tp>
|
|
struct hash<optional<_Tp>>
|
|
: private __poison_hash<remove_const_t<_Tp>>,
|
|
public __optional_hash_call_base<_Tp>
|
|
{
|
|
using result_type [[__deprecated__]] = size_t;
|
|
using argument_type [[__deprecated__]] = optional<_Tp>;
|
|
};
|
|
|
|
template<typename _Tp>
|
|
struct __is_fast_hash<hash<optional<_Tp>>> : __is_fast_hash<hash<_Tp>>
|
|
{ };
|
|
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/// @}
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#if __cpp_deduction_guides >= 201606
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template <typename _Tp> optional(_Tp) -> optional<_Tp>;
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#endif
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_GLIBCXX_END_NAMESPACE_VERSION
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} // namespace std
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#endif // C++17
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#endif // _GLIBCXX_OPTIONAL
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