// <experimental/any> -*- C++ -*-
// Copyright (C) 2014-2015 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library. This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.
// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
// <http://www.gnu.org/licenses/>.
/** @file experimental/any
* This is a TS C++ Library header.
*/
#ifndef _GLIBCXX_EXPERIMENTAL_ANY
#define _GLIBCXX_EXPERIMENTAL_ANY 1
#pragma GCC system_header
#if __cplusplus <= 201103L
# include <bits/c++14_warning.h>
#else
#include <typeinfo>
#include <new>
#include <utility>
#include <type_traits>
namespace std _GLIBCXX_VISIBILITY(default)
{
namespace experimental
{
inline namespace fundamentals_v1
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
/**
* @defgroup any Type-safe container of any type
* @ingroup experimental
*
* A type-safe container for single values of value types, as
* described in n3804 "Any Library Proposal (Revision 3)".
*
* @{
*/
#define __cpp_lib_experimental_any 201411
/**
* @brief Exception class thrown by a failed @c any_cast
* @ingroup exceptions
*/
class bad_any_cast : public bad_cast
{
public:
virtual const char* what() const noexcept { return "bad any_cast"; }
};
[[gnu::noreturn]] inline void __throw_bad_any_cast()
{
#if __cpp_exceptions
throw bad_any_cast{};
#else
__builtin_abort();
#endif
}
/**
* @brief A type-safe container of any type.
*
* An @c any object's state is either empty or it stores a contained object
* of CopyConstructible type.
*/
class any
{
// Holds either pointer to a heap object or the contained object itself.
union _Storage
{
void* _M_ptr;
std::aligned_storage<sizeof(_M_ptr), sizeof(_M_ptr)>::type _M_buffer;
};
template<typename _Tp, typename _Safe = is_trivially_copyable<_Tp>,
bool _Fits = (sizeof(_Tp) <= sizeof(_Storage))>
using _Internal = std::integral_constant<bool, _Safe::value && _Fits>;
template<typename _Tp>
struct _Manager_internal; // uses small-object optimization
template<typename _Tp>
struct _Manager_external; // creates contained object on the heap
template<typename _Tp>
using _Manager = conditional_t<_Internal<_Tp>::value,
_Manager_internal<_Tp>,
_Manager_external<_Tp>>;
template<typename _Tp, typename _Decayed = decay_t<_Tp>>
using _Decay = enable_if_t<!is_same<_Decayed, any>::value, _Decayed>;
public:
// construct/destruct
/// Default constructor, creates an empty object.
any() noexcept : _M_manager(nullptr) { }
/// Copy constructor, copies the state of @p __other
any(const any& __other) : _M_manager(__other._M_manager)
{
if (!__other.empty())
{
_Arg __arg;
__arg._M_any = this;
_M_manager(_Op_clone, &__other, &__arg);
}
}
/**
* @brief Move constructor, transfer the state from @p __other
*
* @post @c __other.empty() (not guaranteed for other implementations)
*/
any(any&& __other) noexcept
: _M_manager(__other._M_manager),
_M_storage(__other._M_storage)
{ __other._M_manager = nullptr; }
/// Construct with a copy of @p __value as the contained object.
template <typename _ValueType, typename _Tp = _Decay<_ValueType>,
typename _Mgr = _Manager<_Tp>>
any(_ValueType&& __value)
: _M_manager(&_Mgr::_S_manage),
_M_storage(_Mgr::_S_create(std::forward<_ValueType>(__value)))
{
static_assert(is_copy_constructible<_Tp>::value,
"The contained object must be CopyConstructible");
}
/// Destructor, calls @c clear()
~any() { clear(); }
// assignments
/// Copy the state of
any& operator=(const any& __rhs)
{
any(__rhs).swap(*this);
return *this;
}
/**
* @brief Move assignment operator
*
* @post @c __rhs.empty() (not guaranteed for other implementations)
*/
any& operator=(any&& __rhs) noexcept
{
any(std::move(__rhs)).swap(*this);
return *this;
}
/// Store a copy of @p __rhs as the contained object.
template<typename _ValueType>
any& operator=(_ValueType&& __rhs)
{
any(std::forward<_ValueType>(__rhs)).swap(*this);
return *this;
}
// modifiers
/// If not empty, destroy the contained object.
void clear() noexcept
{
if (!empty())
{
_M_manager(_Op_destroy, this, nullptr);
_M_manager = nullptr;
}
}
/// Exchange state with another object.
void swap(any& __rhs) noexcept
{
std::swap(_M_manager, __rhs._M_manager);
std::swap(_M_storage, __rhs._M_storage);
}
// observers
/// Reports whether there is a contained object or not.
bool empty() const noexcept { return _M_manager == nullptr; }
#if __cpp_rtti
/// The @c typeid of the contained object, or @c typeid(void) if empty.
const type_info& type() const noexcept
{
if (empty())
return typeid(void);
_Arg __arg;
_M_manager(_Op_get_type_info, this, &__arg);
return *__arg._M_typeinfo;
}
#endif
template<typename _Tp>
static constexpr bool __is_valid_cast()
{ return __or_<is_reference<_Tp>, is_copy_constructible<_Tp>>::value; }
private:
enum _Op { _Op_access, _Op_get_type_info, _Op_clone, _Op_destroy };
union _Arg
{
void* _M_obj;
const std::type_info* _M_typeinfo;
any* _M_any;
};
void (*_M_manager)(_Op, const any*, _Arg*);
_Storage _M_storage;
template<typename _Tp>
friend void* __any_caster(const any* __any)
{
if (__any->_M_manager != &_Manager<decay_t<_Tp>>::_S_manage)
return nullptr;
_Arg __arg;
__any->_M_manager(_Op_access, __any, &__arg);
return __arg._M_obj;
}
// Manage in-place contained object.
template<typename _Tp>
struct _Manager_internal
{
static void
_S_manage(_Op __which, const any* __anyp, _Arg* __arg);
template<typename _Up>
static _Storage
_S_create(_Up&& __value)
{
_Storage __storage;
void* __addr = &__storage._M_buffer;
::new (__addr) _Tp(std::forward<_Up>(__value));
return __storage;
}
template<typename _Alloc, typename _Up>
static _Storage
_S_alloc(const _Alloc&, _Up&& __value)
{
return _S_create(std::forward<_Up>(__value));
}
};
// Manage external contained object.
template<typename _Tp>
struct _Manager_external
{
static void
_S_manage(_Op __which, const any* __anyp, _Arg* __arg);
template<typename _Up>
static _Storage
_S_create(_Up&& __value)
{
_Storage __storage;
__storage._M_ptr = new _Tp(std::forward<_Up>(__value));
return __storage;
}
};
};
/// Exchange the states of two @c any objects.
inline void swap(any& __x, any& __y) noexcept { __x.swap(__y); }
/**
* @brief Access the contained object.
*
* @tparam _ValueType A const-reference or CopyConstructible type.
* @param __any The object to access.
* @return The contained object.
* @throw bad_any_cast If <code>
* __any.type() != typeid(remove_reference_t<_ValueType>)
* </code>
*/
template<typename _ValueType>
inline _ValueType any_cast(const any& __any)
{
static_assert(any::__is_valid_cast<_ValueType>(),
"Template argument must be a reference or CopyConstructible type");
auto __p = any_cast<add_const_t<remove_reference_t<_ValueType>>>(&__any);
if (__p)
return *__p;
__throw_bad_any_cast();
}
/**
* @brief Access the contained object.
*
* @tparam _ValueType A reference or CopyConstructible type.
* @param __any The object to access.
* @return The contained object.
* @throw bad_any_cast If <code>
* __any.type() != typeid(remove_reference_t<_ValueType>)
* </code>
*
* @{
*/
template<typename _ValueType>
inline _ValueType any_cast(any& __any)
{
static_assert(any::__is_valid_cast<_ValueType>(),
"Template argument must be a reference or CopyConstructible type");
auto __p = any_cast<remove_reference_t<_ValueType>>(&__any);
if (__p)
return *__p;
__throw_bad_any_cast();
}
template<typename _ValueType>
inline _ValueType any_cast(any&& __any)
{
static_assert(any::__is_valid_cast<_ValueType>(),
"Template argument must be a reference or CopyConstructible type");
auto __p = any_cast<remove_reference_t<_ValueType>>(&__any);
if (__p)
return *__p;
__throw_bad_any_cast();
}
// @}
/**
* @brief Access the contained object.
*
* @tparam _ValueType The type of the contained object.
* @param __any A pointer to the object to access.
* @return The address of the contained object if <code>
* __any != nullptr && __any.type() == typeid(_ValueType)
* </code>, otherwise a null pointer.
*
* @{
*/
template<typename _ValueType>
inline const _ValueType* any_cast(const any* __any) noexcept
{
if (__any)
return static_cast<_ValueType*>(__any_caster<_ValueType>(__any));
return nullptr;
}
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);
break;
case _Op_destroy:
__ptr->~_Tp();
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);
break;
case _Op_destroy:
delete __ptr;
break;
}
}
// @} group any
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace fundamentals_v1
} // namespace experimental
} // namespace std
#endif // C++14
#endif // _GLIBCXX_EXPERIMENTAL_ANY