// <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