0,0 → 1,437 |
// <experimental/any> -*- C++ -*- |
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// 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. |
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// 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. |
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// 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. |
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// 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/>. |
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/** @file experimental/any |
* This is a TS C++ Library header. |
*/ |
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#ifndef _GLIBCXX_EXPERIMENTAL_ANY |
#define _GLIBCXX_EXPERIMENTAL_ANY 1 |
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#pragma GCC system_header |
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#if __cplusplus <= 201103L |
# include <bits/c++14_warning.h> |
#else |
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#include <typeinfo> |
#include <new> |
#include <utility> |
#include <type_traits> |
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namespace std _GLIBCXX_VISIBILITY(default) |
{ |
namespace experimental |
{ |
inline namespace fundamentals_v1 |
{ |
_GLIBCXX_BEGIN_NAMESPACE_VERSION |
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/** |
* @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)". |
* |
* @{ |
*/ |
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#define __cpp_lib_experimental_any 201411 |
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/** |
* @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"; } |
}; |
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[[gnu::noreturn]] inline void __throw_bad_any_cast() |
{ |
#if __cpp_exceptions |
throw bad_any_cast{}; |
#else |
__builtin_abort(); |
#endif |
} |
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/** |
* @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; |
}; |
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template<typename _Tp, typename _Safe = is_trivially_copyable<_Tp>, |
bool _Fits = (sizeof(_Tp) <= sizeof(_Storage))> |
using _Internal = std::integral_constant<bool, _Safe::value && _Fits>; |
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template<typename _Tp> |
struct _Manager_internal; // uses small-object optimization |
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template<typename _Tp> |
struct _Manager_external; // creates contained object on the heap |
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template<typename _Tp> |
using _Manager = conditional_t<_Internal<_Tp>::value, |
_Manager_internal<_Tp>, |
_Manager_external<_Tp>>; |
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template<typename _Tp, typename _Decayed = decay_t<_Tp>> |
using _Decay = enable_if_t<!is_same<_Decayed, any>::value, _Decayed>; |
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public: |
// construct/destruct |
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/// Default constructor, creates an empty object. |
any() noexcept : _M_manager(nullptr) { } |
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/// 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); |
} |
} |
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/** |
* @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; } |
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/// 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"); |
} |
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/// Destructor, calls @c clear() |
~any() { clear(); } |
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// assignments |
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/// Copy the state of |
any& operator=(const any& __rhs) |
{ |
any(__rhs).swap(*this); |
return *this; |
} |
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/** |
* @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; |
} |
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/// 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; |
} |
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// modifiers |
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/// If not empty, destroy the contained object. |
void clear() noexcept |
{ |
if (!empty()) |
{ |
_M_manager(_Op_destroy, this, nullptr); |
_M_manager = nullptr; |
} |
} |
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/// Exchange state with another object. |
void swap(any& __rhs) noexcept |
{ |
std::swap(_M_manager, __rhs._M_manager); |
std::swap(_M_storage, __rhs._M_storage); |
} |
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// observers |
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/// Reports whether there is a contained object or not. |
bool empty() const noexcept { return _M_manager == nullptr; } |
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#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 |
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template<typename _Tp> |
static constexpr bool __is_valid_cast() |
{ return __or_<is_reference<_Tp>, is_copy_constructible<_Tp>>::value; } |
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private: |
enum _Op { _Op_access, _Op_get_type_info, _Op_clone, _Op_destroy }; |
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union _Arg |
{ |
void* _M_obj; |
const std::type_info* _M_typeinfo; |
any* _M_any; |
}; |
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void (*_M_manager)(_Op, const any*, _Arg*); |
_Storage _M_storage; |
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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; |
} |
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// Manage in-place contained object. |
template<typename _Tp> |
struct _Manager_internal |
{ |
static void |
_S_manage(_Op __which, const any* __anyp, _Arg* __arg); |
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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; |
} |
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template<typename _Alloc, typename _Up> |
static _Storage |
_S_alloc(const _Alloc&, _Up&& __value) |
{ |
return _S_create(std::forward<_Up>(__value)); |
} |
}; |
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// Manage external contained object. |
template<typename _Tp> |
struct _Manager_external |
{ |
static void |
_S_manage(_Op __which, const any* __anyp, _Arg* __arg); |
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template<typename _Up> |
static _Storage |
_S_create(_Up&& __value) |
{ |
_Storage __storage; |
__storage._M_ptr = new _Tp(std::forward<_Up>(__value)); |
return __storage; |
} |
}; |
}; |
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/// Exchange the states of two @c any objects. |
inline void swap(any& __x, any& __y) noexcept { __x.swap(__y); } |
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/** |
* @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(); |
} |
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/** |
* @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(); |
} |
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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(); |
} |
// @} |
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/** |
* @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; |
} |
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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; |
} |
// @} |
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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; |
} |
} |
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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; |
} |
} |
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// @} group any |
_GLIBCXX_END_NAMESPACE_VERSION |
} // namespace fundamentals_v1 |
} // namespace experimental |
} // namespace std |
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#endif // C++14 |
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#endif // _GLIBCXX_EXPERIMENTAL_ANY |