mirror of git://gcc.gnu.org/git/gcc.git
607 lines
17 KiB
C++
607 lines
17 KiB
C++
// <any> -*- C++ -*-
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// Copyright (C) 2014-2016 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/any
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* This is a Standard C++ Library header.
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*/
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#ifndef _GLIBCXX_ANY
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#define _GLIBCXX_ANY 1
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#pragma GCC system_header
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#if __cplusplus <= 201402L
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# include <bits/c++17_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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_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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/**
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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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constexpr _Storage() : _M_ptr{nullptr} {}
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// Prevent trivial copies of this type, buffer might hold a non-POD.
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_Storage(const _Storage&) = delete;
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_Storage& operator=(const _Storage&) = delete;
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void* _M_ptr;
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aligned_storage<sizeof(_M_ptr), alignof(void*)>::type _M_buffer;
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};
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template<typename _Tp, typename _Safe = is_nothrow_move_constructible<_Tp>,
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bool _Fits = (sizeof(_Tp) <= sizeof(_Storage))
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&& (alignof(_Tp) <= alignof(_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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constexpr 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)
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{
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if (!__other.has_value())
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_M_manager = nullptr;
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else
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{
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_Arg __arg;
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__arg._M_any = this;
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__other._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.has_value() (this postcondition is a GNU extension)
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*/
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any(any&& __other) noexcept
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{
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if (!__other.has_value())
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_M_manager = nullptr;
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else
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{
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_Arg __arg;
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__arg._M_any = this;
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__other._M_manager(_Op_xfer, &__other, &__arg);
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}
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}
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template <typename _Tp, typename... _Args>
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using __any_constructible_t =
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enable_if_t<__and_<is_copy_constructible<_Tp>,
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is_constructible<_Tp, _Args...>>::value,
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bool>;
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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_constructible_t<_Tp, _ValueType&&> = true,
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enable_if_t<!__is_in_place_type<_ValueType>::value, bool> = true>
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any(_ValueType&& __value)
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: _M_manager(&_Mgr::_S_manage)
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{
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_Mgr::_S_create(_M_storage, std::forward<_ValueType>(__value));
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}
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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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enable_if_t<__and_<is_copy_constructible<_Tp>,
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__not_<is_constructible<_Tp, _ValueType&&>>,
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__not_<__is_in_place_type<_ValueType>>>::value,
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bool> = false>
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any(_ValueType&& __value)
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: _M_manager(&_Mgr::_S_manage)
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{
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_Mgr::_S_create(_M_storage, __value);
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}
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/// Construct with an object created from @p __args as the contained object.
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template <typename _ValueType, typename... _Args,
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typename _Tp = _Decay<_ValueType>,
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typename _Mgr = _Manager<_Tp>,
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__any_constructible_t<_Tp, _Args&&...> = false>
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any(in_place_type_t<_ValueType>, _Args&&... __args)
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: _M_manager(&_Mgr::_S_manage)
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{
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_Mgr::_S_create(_M_storage, std::forward<_Args>(__args)...);
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}
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/// Construct with an object created from @p __il and @p __args as
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/// the contained object.
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template <typename _ValueType, typename _Up, typename... _Args,
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typename _Tp = _Decay<_ValueType>,
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typename _Mgr = _Manager<_Tp>,
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__any_constructible_t<_Tp, initializer_list<_Up>,
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_Args&&...> = false>
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any(in_place_type_t<_ValueType>,
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initializer_list<_Up> __il, _Args&&... __args)
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: _M_manager(&_Mgr::_S_manage)
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{
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_Mgr::_S_create(_M_storage, __il, std::forward<_Args>(__args)...);
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}
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/// Destructor, calls @c reset()
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~any() { reset(); }
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// assignments
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/// Copy the state of another object.
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any& operator=(const any& __rhs)
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{
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if (!__rhs.has_value())
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reset();
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else if (this != &__rhs)
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{
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if (has_value())
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_M_manager(_Op_destroy, this, nullptr);
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_Arg __arg;
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__arg._M_any = this;
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__rhs._M_manager(_Op_clone, &__rhs, &__arg);
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}
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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.has_value() (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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if (!__rhs.has_value())
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reset();
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else if (this != &__rhs)
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{
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if (has_value())
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_M_manager(_Op_destroy, this, nullptr);
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_Arg __arg;
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__arg._M_any = this;
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__rhs._M_manager(_Op_xfer, &__rhs, &__arg);
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}
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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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typename _Tp = _Decay<_ValueType>>
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enable_if_t<is_copy_constructible<_Tp>::value, any&>
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operator=(_ValueType&& __rhs)
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{
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*this = any(std::forward<_ValueType>(__rhs));
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return *this;
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}
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/// Emplace with an object created from @p __args as the contained object.
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template <typename _ValueType, typename... _Args,
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typename _Tp = _Decay<_ValueType>,
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typename _Mgr = _Manager<_Tp>,
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__any_constructible_t<_Tp, _Args&&...> = false>
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void emplace(_Args&&... __args)
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{
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reset();
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_M_manager = &_Mgr::_S_manage;
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_Mgr::_S_create(_M_storage, std::forward<_Args>(__args)...);
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}
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/// Emplace with an object created from @p __il and @p __args as
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/// the contained object.
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template <typename _ValueType, typename _Up, typename... _Args,
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typename _Tp = _Decay<_ValueType>,
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typename _Mgr = _Manager<_Tp>,
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__any_constructible_t<_Tp, initializer_list<_Up>,
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_Args&&...> = false>
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void emplace(initializer_list<_Up> __il, _Args&&... __args)
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{
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reset();
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_M_manager = &_Mgr::_S_manage;
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_Mgr::_S_create(_M_storage, __il, std::forward<_Args>(__args)...);
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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 reset() noexcept
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{
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if (has_value())
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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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if (!has_value() && !__rhs.has_value())
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return;
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if (has_value() && __rhs.has_value())
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{
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if (this == &__rhs)
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return;
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any __tmp;
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_Arg __arg;
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__arg._M_any = &__tmp;
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__rhs._M_manager(_Op_xfer, &__rhs, &__arg);
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__arg._M_any = &__rhs;
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_M_manager(_Op_xfer, this, &__arg);
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__arg._M_any = this;
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__tmp._M_manager(_Op_xfer, &__tmp, &__arg);
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}
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else
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{
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any* __empty = !has_value() ? this : &__rhs;
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any* __full = !has_value() ? &__rhs : this;
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_Arg __arg;
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__arg._M_any = __empty;
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__full->_M_manager(_Op_xfer, __full, &__arg);
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}
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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 has_value() 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 (!has_value())
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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 {
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_Op_access, _Op_get_type_info, _Op_clone, _Op_destroy, _Op_xfer
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};
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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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// 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 void
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_S_create(_Storage& __storage, _Up&& __value)
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{
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void* __addr = &__storage._M_buffer;
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::new (__addr) _Tp(std::forward<_Up>(__value));
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}
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template<typename... _Args>
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static void
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_S_create(_Storage& __storage, _Args&&... __args)
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{
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void* __addr = &__storage._M_buffer;
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::new (__addr) _Tp(std::forward<_Args>(__args)...);
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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 void
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_S_create(_Storage& __storage, _Up&& __value)
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{
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__storage._M_ptr = new _Tp(std::forward<_Up>(__value));
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}
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template<typename... _Args>
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static void
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_S_create(_Storage& __storage, _Args&&... __args)
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{
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__storage._M_ptr = new _Tp(std::forward<_Args>(__args)...);
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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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/// Create an any holding a @c _Tp constructed from @c __args.
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template <typename _Tp, typename... _Args>
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any make_any(_Args&&... __args)
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{
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return any(in_place<_Tp>, std::forward<_Args>(__args)...);
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}
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/// Create an any holding a @c _Tp constructed from @c __il and @c __args.
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template <typename _Tp, typename _Up, typename... _Args>
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any make_any(initializer_list<_Up> __il, _Args&&... __args)
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{
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return any(in_place<_Tp>, __il, std::forward<_Args>(__args)...);
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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 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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typename enable_if<!is_move_constructible<_ValueType>::value
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|| is_lvalue_reference<_ValueType>::value,
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bool>::type = true>
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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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typename enable_if<is_move_constructible<_ValueType>::value
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&& !is_lvalue_reference<_ValueType>::value,
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bool>::type = false>
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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 std::move(*__p);
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__throw_bad_any_cast();
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}
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// @}
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template<typename _Tp>
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void* __any_caster(const any* __any)
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{
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if (__any->_M_manager != &any::_Manager<decay_t<_Tp>>::_S_manage)
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return nullptr;
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any::_Arg __arg;
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__any->_M_manager(any::_Op_access, __any, &__arg);
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return __arg._M_obj;
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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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}
|
|
|
|
template<typename _ValueType>
|
|
inline _ValueType* any_cast(any* __any) noexcept
|
|
{
|
|
if (__any)
|
|
return static_cast<_ValueType*>(__any_caster<_ValueType>(__any));
|
|
return nullptr;
|
|
}
|
|
// @}
|
|
|
|
template<typename _Tp>
|
|
void
|
|
any::_Manager_internal<_Tp>::
|
|
_S_manage(_Op __which, const any* __any, _Arg* __arg)
|
|
{
|
|
// The contained object is in _M_storage._M_buffer
|
|
auto __ptr = reinterpret_cast<const _Tp*>(&__any->_M_storage._M_buffer);
|
|
switch (__which)
|
|
{
|
|
case _Op_access:
|
|
__arg->_M_obj = const_cast<_Tp*>(__ptr);
|
|
break;
|
|
case _Op_get_type_info:
|
|
#if __cpp_rtti
|
|
__arg->_M_typeinfo = &typeid(_Tp);
|
|
#endif
|
|
break;
|
|
case _Op_clone:
|
|
::new(&__arg->_M_any->_M_storage._M_buffer) _Tp(*__ptr);
|
|
__arg->_M_any->_M_manager = __any->_M_manager;
|
|
break;
|
|
case _Op_destroy:
|
|
__ptr->~_Tp();
|
|
break;
|
|
case _Op_xfer:
|
|
::new(&__arg->_M_any->_M_storage._M_buffer) _Tp(*__ptr);
|
|
__ptr->~_Tp();
|
|
__arg->_M_any->_M_manager = __any->_M_manager;
|
|
const_cast<any*>(__any)->_M_manager = nullptr;
|
|
break;
|
|
}
|
|
}
|
|
|
|
template<typename _Tp>
|
|
void
|
|
any::_Manager_external<_Tp>::
|
|
_S_manage(_Op __which, const any* __any, _Arg* __arg)
|
|
{
|
|
// The contained object is *_M_storage._M_ptr
|
|
auto __ptr = static_cast<const _Tp*>(__any->_M_storage._M_ptr);
|
|
switch (__which)
|
|
{
|
|
case _Op_access:
|
|
__arg->_M_obj = const_cast<_Tp*>(__ptr);
|
|
break;
|
|
case _Op_get_type_info:
|
|
#if __cpp_rtti
|
|
__arg->_M_typeinfo = &typeid(_Tp);
|
|
#endif
|
|
break;
|
|
case _Op_clone:
|
|
__arg->_M_any->_M_storage._M_ptr = new _Tp(*__ptr);
|
|
__arg->_M_any->_M_manager = __any->_M_manager;
|
|
break;
|
|
case _Op_destroy:
|
|
delete __ptr;
|
|
break;
|
|
case _Op_xfer:
|
|
__arg->_M_any->_M_storage._M_ptr = __any->_M_storage._M_ptr;
|
|
__arg->_M_any->_M_manager = __any->_M_manager;
|
|
const_cast<any*>(__any)->_M_manager = nullptr;
|
|
break;
|
|
}
|
|
}
|
|
|
|
/// @}
|
|
|
|
_GLIBCXX_END_NAMESPACE_VERSION
|
|
} // namespace std
|
|
|
|
#endif // C++14
|
|
|
|
#endif // _GLIBCXX_ANY
|