| // <cast.h> -*- C++ -*- |
| |
| // Copyright (C) 2008-2020 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 ext/cast.h |
| * This is an internal header file, included by other library headers. |
| * Do not attempt to use it directly. @headername{ext/pointer.h} |
| */ |
| |
| #ifndef _GLIBCXX_CAST_H |
| #define _GLIBCXX_CAST_H 1 |
| |
| namespace __gnu_cxx _GLIBCXX_VISIBILITY(default) |
| { |
| _GLIBCXX_BEGIN_NAMESPACE_VERSION |
| |
| /** |
| * These functions are here to allow containers to support non standard |
| * pointer types. For normal pointers, these resolve to the use of the |
| * standard cast operation. For other types the functions will perform |
| * the appropriate cast to/from the custom pointer class so long as that |
| * class meets the following conditions: |
| * 1) has a typedef element_type which names tehe type it points to. |
| * 2) has a get() const method which returns element_type*. |
| * 3) has a constructor which can take one element_type* argument. |
| */ |
| |
| /** |
| * This type supports the semantics of the pointer cast operators (below.) |
| */ |
| template<typename _ToType> |
| struct _Caster |
| { typedef typename _ToType::element_type* type; }; |
| |
| template<typename _ToType> |
| struct _Caster<_ToType*> |
| { typedef _ToType* type; }; |
| |
| /** |
| * Casting operations for cases where _FromType is not a standard pointer. |
| * _ToType can be a standard or non-standard pointer. Given that _FromType |
| * is not a pointer, it must have a get() method that returns the standard |
| * pointer equivalent of the address it points to, and must have an |
| * element_type typedef which names the type it points to. |
| */ |
| template<typename _ToType, typename _FromType> |
| inline _ToType |
| __static_pointer_cast(const _FromType& __arg) |
| { return _ToType(static_cast<typename _Caster<_ToType>:: |
| type>(__arg.get())); } |
| |
| template<typename _ToType, typename _FromType> |
| inline _ToType |
| __dynamic_pointer_cast(const _FromType& __arg) |
| { return _ToType(dynamic_cast<typename _Caster<_ToType>:: |
| type>(__arg.get())); } |
| |
| template<typename _ToType, typename _FromType> |
| inline _ToType |
| __const_pointer_cast(const _FromType& __arg) |
| { return _ToType(const_cast<typename _Caster<_ToType>:: |
| type>(__arg.get())); } |
| |
| template<typename _ToType, typename _FromType> |
| inline _ToType |
| __reinterpret_pointer_cast(const _FromType& __arg) |
| { return _ToType(reinterpret_cast<typename _Caster<_ToType>:: |
| type>(__arg.get())); } |
| |
| /** |
| * Casting operations for cases where _FromType is a standard pointer. |
| * _ToType can be a standard or non-standard pointer. |
| */ |
| template<typename _ToType, typename _FromType> |
| inline _ToType |
| __static_pointer_cast(_FromType* __arg) |
| { return _ToType(static_cast<typename _Caster<_ToType>:: |
| type>(__arg)); } |
| |
| template<typename _ToType, typename _FromType> |
| inline _ToType |
| __dynamic_pointer_cast(_FromType* __arg) |
| { return _ToType(dynamic_cast<typename _Caster<_ToType>:: |
| type>(__arg)); } |
| |
| template<typename _ToType, typename _FromType> |
| inline _ToType |
| __const_pointer_cast(_FromType* __arg) |
| { return _ToType(const_cast<typename _Caster<_ToType>:: |
| type>(__arg)); } |
| |
| template<typename _ToType, typename _FromType> |
| inline _ToType |
| __reinterpret_pointer_cast(_FromType* __arg) |
| { return _ToType(reinterpret_cast<typename _Caster<_ToType>:: |
| type>(__arg)); } |
| |
| _GLIBCXX_END_NAMESPACE_VERSION |
| } // namespace |
| |
| #endif // _GLIBCXX_CAST_H |