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https://github.com/autc04/Retro68.git
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438 lines
11 KiB
C++
438 lines
11 KiB
C++
// <experimental/any> -*- C++ -*-
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// Copyright (C) 2014-2015 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/any
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* This is a TS C++ Library header.
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*/
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#ifndef _GLIBCXX_EXPERIMENTAL_ANY
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#define _GLIBCXX_EXPERIMENTAL_ANY 1
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#pragma GCC system_header
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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 <typeinfo>
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#include <new>
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#include <utility>
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#include <type_traits>
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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 any Type-safe container of any type
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* @ingroup experimental
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*
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* A type-safe container for single values of value types, as
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* described in n3804 "Any Library Proposal (Revision 3)".
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*
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* @{
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*/
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#define __cpp_lib_experimental_any 201411
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/**
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* @brief Exception class thrown by a failed @c any_cast
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* @ingroup exceptions
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*/
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class bad_any_cast : public bad_cast
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{
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public:
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virtual const char* what() const noexcept { return "bad any_cast"; }
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};
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[[gnu::noreturn]] inline void __throw_bad_any_cast()
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{
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#if __cpp_exceptions
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throw bad_any_cast{};
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#else
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__builtin_abort();
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#endif
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}
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/**
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* @brief A type-safe container of any type.
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*
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* An @c any object's state is either empty or it stores a contained object
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* of CopyConstructible type.
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*/
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class any
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{
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// Holds either pointer to a heap object or the contained object itself.
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union _Storage
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{
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void* _M_ptr;
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std::aligned_storage<sizeof(_M_ptr), sizeof(_M_ptr)>::type _M_buffer;
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};
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template<typename _Tp, typename _Safe = is_trivially_copyable<_Tp>,
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bool _Fits = (sizeof(_Tp) <= sizeof(_Storage))>
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using _Internal = std::integral_constant<bool, _Safe::value && _Fits>;
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template<typename _Tp>
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struct _Manager_internal; // uses small-object optimization
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template<typename _Tp>
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struct _Manager_external; // creates contained object on the heap
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template<typename _Tp>
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using _Manager = conditional_t<_Internal<_Tp>::value,
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_Manager_internal<_Tp>,
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_Manager_external<_Tp>>;
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template<typename _Tp, typename _Decayed = decay_t<_Tp>>
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using _Decay = enable_if_t<!is_same<_Decayed, any>::value, _Decayed>;
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public:
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// construct/destruct
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/// Default constructor, creates an empty object.
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any() noexcept : _M_manager(nullptr) { }
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/// Copy constructor, copies the state of @p __other
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any(const any& __other) : _M_manager(__other._M_manager)
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{
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if (!__other.empty())
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{
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_Arg __arg;
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__arg._M_any = this;
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_M_manager(_Op_clone, &__other, &__arg);
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}
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}
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/**
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* @brief Move constructor, transfer the state from @p __other
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*
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* @post @c __other.empty() (not guaranteed for other implementations)
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*/
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any(any&& __other) noexcept
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: _M_manager(__other._M_manager),
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_M_storage(__other._M_storage)
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{ __other._M_manager = nullptr; }
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/// Construct with a copy of @p __value as the contained object.
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template <typename _ValueType, typename _Tp = _Decay<_ValueType>,
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typename _Mgr = _Manager<_Tp>>
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any(_ValueType&& __value)
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: _M_manager(&_Mgr::_S_manage),
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_M_storage(_Mgr::_S_create(std::forward<_ValueType>(__value)))
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{
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static_assert(is_copy_constructible<_Tp>::value,
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"The contained object must be CopyConstructible");
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}
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/// Destructor, calls @c clear()
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~any() { clear(); }
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// assignments
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/// Copy the state of
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any& operator=(const any& __rhs)
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{
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any(__rhs).swap(*this);
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return *this;
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}
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/**
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* @brief Move assignment operator
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*
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* @post @c __rhs.empty() (not guaranteed for other implementations)
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*/
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any& operator=(any&& __rhs) noexcept
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{
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any(std::move(__rhs)).swap(*this);
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return *this;
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}
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/// Store a copy of @p __rhs as the contained object.
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template<typename _ValueType>
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any& operator=(_ValueType&& __rhs)
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{
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any(std::forward<_ValueType>(__rhs)).swap(*this);
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return *this;
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}
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// modifiers
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/// If not empty, destroy the contained object.
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void clear() noexcept
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{
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if (!empty())
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{
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_M_manager(_Op_destroy, this, nullptr);
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_M_manager = nullptr;
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}
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}
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/// Exchange state with another object.
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void swap(any& __rhs) noexcept
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{
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std::swap(_M_manager, __rhs._M_manager);
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std::swap(_M_storage, __rhs._M_storage);
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}
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// observers
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/// Reports whether there is a contained object or not.
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bool empty() const noexcept { return _M_manager == nullptr; }
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#if __cpp_rtti
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/// The @c typeid of the contained object, or @c typeid(void) if empty.
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const type_info& type() const noexcept
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{
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if (empty())
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return typeid(void);
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_Arg __arg;
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_M_manager(_Op_get_type_info, this, &__arg);
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return *__arg._M_typeinfo;
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}
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#endif
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template<typename _Tp>
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static constexpr bool __is_valid_cast()
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{ return __or_<is_reference<_Tp>, is_copy_constructible<_Tp>>::value; }
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private:
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enum _Op { _Op_access, _Op_get_type_info, _Op_clone, _Op_destroy };
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union _Arg
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{
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void* _M_obj;
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const std::type_info* _M_typeinfo;
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any* _M_any;
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};
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void (*_M_manager)(_Op, const any*, _Arg*);
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_Storage _M_storage;
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template<typename _Tp>
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friend void* __any_caster(const any* __any)
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{
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if (__any->_M_manager != &_Manager<decay_t<_Tp>>::_S_manage)
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return nullptr;
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_Arg __arg;
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__any->_M_manager(_Op_access, __any, &__arg);
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return __arg._M_obj;
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}
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// Manage in-place contained object.
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template<typename _Tp>
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struct _Manager_internal
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{
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static void
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_S_manage(_Op __which, const any* __anyp, _Arg* __arg);
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template<typename _Up>
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static _Storage
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_S_create(_Up&& __value)
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{
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_Storage __storage;
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void* __addr = &__storage._M_buffer;
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::new (__addr) _Tp(std::forward<_Up>(__value));
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return __storage;
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}
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template<typename _Alloc, typename _Up>
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static _Storage
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_S_alloc(const _Alloc&, _Up&& __value)
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{
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return _S_create(std::forward<_Up>(__value));
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}
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};
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// Manage external contained object.
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template<typename _Tp>
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struct _Manager_external
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{
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static void
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_S_manage(_Op __which, const any* __anyp, _Arg* __arg);
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template<typename _Up>
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static _Storage
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_S_create(_Up&& __value)
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{
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_Storage __storage;
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__storage._M_ptr = new _Tp(std::forward<_Up>(__value));
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return __storage;
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}
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};
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};
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/// Exchange the states of two @c any objects.
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inline void swap(any& __x, any& __y) noexcept { __x.swap(__y); }
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/**
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* @brief Access the contained object.
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*
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* @tparam _ValueType A const-reference or CopyConstructible type.
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* @param __any The object to access.
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* @return The contained object.
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* @throw bad_any_cast If <code>
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* __any.type() != typeid(remove_reference_t<_ValueType>)
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* </code>
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*/
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template<typename _ValueType>
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inline _ValueType any_cast(const any& __any)
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{
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static_assert(any::__is_valid_cast<_ValueType>(),
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"Template argument must be a reference or CopyConstructible type");
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auto __p = any_cast<add_const_t<remove_reference_t<_ValueType>>>(&__any);
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if (__p)
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return *__p;
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__throw_bad_any_cast();
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}
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/**
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* @brief Access the contained object.
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*
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* @tparam _ValueType A reference or CopyConstructible type.
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* @param __any The object to access.
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* @return The contained object.
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* @throw bad_any_cast If <code>
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* __any.type() != typeid(remove_reference_t<_ValueType>)
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* </code>
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*
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* @{
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*/
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template<typename _ValueType>
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inline _ValueType any_cast(any& __any)
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{
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static_assert(any::__is_valid_cast<_ValueType>(),
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"Template argument must be a reference or CopyConstructible type");
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auto __p = any_cast<remove_reference_t<_ValueType>>(&__any);
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if (__p)
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return *__p;
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__throw_bad_any_cast();
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}
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template<typename _ValueType>
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inline _ValueType any_cast(any&& __any)
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{
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static_assert(any::__is_valid_cast<_ValueType>(),
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"Template argument must be a reference or CopyConstructible type");
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auto __p = any_cast<remove_reference_t<_ValueType>>(&__any);
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if (__p)
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return *__p;
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__throw_bad_any_cast();
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}
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// @}
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/**
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* @brief Access the contained object.
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*
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* @tparam _ValueType The type of the contained object.
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* @param __any A pointer to the object to access.
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* @return The address of the contained object if <code>
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* __any != nullptr && __any.type() == typeid(_ValueType)
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* </code>, otherwise a null pointer.
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*
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* @{
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*/
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template<typename _ValueType>
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inline const _ValueType* any_cast(const any* __any) noexcept
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{
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if (__any)
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return static_cast<_ValueType*>(__any_caster<_ValueType>(__any));
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return nullptr;
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}
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template<typename _ValueType>
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inline _ValueType* any_cast(any* __any) noexcept
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{
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if (__any)
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return static_cast<_ValueType*>(__any_caster<_ValueType>(__any));
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return nullptr;
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}
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// @}
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template<typename _Tp>
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void
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any::_Manager_internal<_Tp>::
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_S_manage(_Op __which, const any* __any, _Arg* __arg)
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{
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// The contained object is in _M_storage._M_buffer
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auto __ptr = reinterpret_cast<const _Tp*>(&__any->_M_storage._M_buffer);
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switch (__which)
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{
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case _Op_access:
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__arg->_M_obj = const_cast<_Tp*>(__ptr);
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break;
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case _Op_get_type_info:
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#if __cpp_rtti
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__arg->_M_typeinfo = &typeid(_Tp);
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#endif
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break;
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case _Op_clone:
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::new(&__arg->_M_any->_M_storage._M_buffer) _Tp(*__ptr);
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break;
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case _Op_destroy:
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__ptr->~_Tp();
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break;
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}
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}
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template<typename _Tp>
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void
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any::_Manager_external<_Tp>::
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_S_manage(_Op __which, const any* __any, _Arg* __arg)
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{
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// The contained object is *_M_storage._M_ptr
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auto __ptr = static_cast<const _Tp*>(__any->_M_storage._M_ptr);
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switch (__which)
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{
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case _Op_access:
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__arg->_M_obj = const_cast<_Tp*>(__ptr);
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break;
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case _Op_get_type_info:
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#if __cpp_rtti
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__arg->_M_typeinfo = &typeid(_Tp);
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#endif
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break;
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case _Op_clone:
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__arg->_M_any->_M_storage._M_ptr = new _Tp(*__ptr);
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break;
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case _Op_destroy:
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delete __ptr;
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break;
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}
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}
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// @} group any
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_GLIBCXX_END_NAMESPACE_VERSION
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} // namespace fundamentals_v1
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} // namespace experimental
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} // namespace std
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#endif // C++14
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#endif // _GLIBCXX_EXPERIMENTAL_ANY
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