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jeremybenn |
// <cast.h> -*- C++ -*-
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// Copyright (C) 2008, 2009 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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#ifndef _CAST_H
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#define _CAST_H 1
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_GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
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/**
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* These functions are here to allow containers to support non standard
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* pointer types. For normal pointers, these resolve to the use of the
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* standard cast operation. For other types the functions will perform
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* the apprpriate cast to/from the custom pointer class so long as that
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* class meets the following conditions:
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* 1) has a typedef element_type which names tehe type it points to.
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* 2) has a get() const method which returns element_type*.
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* 3) has a constructor which can take one element_type* argument.
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*/
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/**
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* This type supports the semantics of the pointer cast operators (below.)
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*/
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template<typename _ToType>
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struct _Caster
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{ typedef typename _ToType::element_type* type; };
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template<typename _ToType>
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struct _Caster<_ToType*>
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{ typedef _ToType* type; };
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/**
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* Casting operations for cases where _FromType is not a standard pointer.
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* _ToType can be a standard or non-standard pointer. Given that _FromType
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* is not a pointer, it must have a get() method that returns the standard
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* pointer equivalent of the address it points to, and must have an
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* element_type typedef which names the type it points to.
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*/
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template<typename _ToType, typename _FromType>
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inline _ToType
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__static_pointer_cast(const _FromType& __arg)
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{ return _ToType(static_cast<typename _Caster<_ToType>::
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type>(__arg.get())); }
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template<typename _ToType, typename _FromType>
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inline _ToType
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__dynamic_pointer_cast(const _FromType& __arg)
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{ return _ToType(dynamic_cast<typename _Caster<_ToType>::
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type>(__arg.get())); }
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template<typename _ToType, typename _FromType>
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inline _ToType
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__const_pointer_cast(const _FromType& __arg)
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{ return _ToType(const_cast<typename _Caster<_ToType>::
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type>(__arg.get())); }
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template<typename _ToType, typename _FromType>
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inline _ToType
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__reinterpret_pointer_cast(const _FromType& __arg)
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{ return _ToType(reinterpret_cast<typename _Caster<_ToType>::
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type>(__arg.get())); }
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/**
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* Casting operations for cases where _FromType is a standard pointer.
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* _ToType can be a standard or non-standard pointer.
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*/
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template<typename _ToType, typename _FromType>
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inline _ToType
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__static_pointer_cast(_FromType* __arg)
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{ return _ToType(static_cast<typename _Caster<_ToType>::
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type>(__arg)); }
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template<typename _ToType, typename _FromType>
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inline _ToType
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__dynamic_pointer_cast(_FromType* __arg)
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{ return _ToType(dynamic_cast<typename _Caster<_ToType>::
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type>(__arg)); }
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template<typename _ToType, typename _FromType>
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inline _ToType
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__const_pointer_cast(_FromType* __arg)
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{ return _ToType(const_cast<typename _Caster<_ToType>::
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type>(__arg)); }
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template<typename _ToType, typename _FromType>
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inline _ToType
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__reinterpret_pointer_cast(_FromType* __arg)
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{ return _ToType(reinterpret_cast<typename _Caster<_ToType>::
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type>(__arg)); }
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_GLIBCXX_END_NAMESPACE
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#endif // _CAST_H
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