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Diffstat (limited to 'libstdc++-v3/include/ext/cast.h')
| -rw-r--r-- | libstdc++-v3/include/ext/cast.h | 121 |
1 files changed, 121 insertions, 0 deletions
diff --git a/libstdc++-v3/include/ext/cast.h b/libstdc++-v3/include/ext/cast.h new file mode 100644 index 000000000..f3384f9a5 --- /dev/null +++ b/libstdc++-v3/include/ext/cast.h @@ -0,0 +1,121 @@ +// <cast.h> -*- C++ -*- + +// Copyright (C) 2008, 2009, 2010 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 apprpriate 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 |