2008-11-07 Paolo Carlini <paolo.carlini@oracle.com>

* Complete last commit.

From-SVN: r141675

libstdc++-v3/include/ext/cast.h

@@ -0,0 +1,121 @@
+// <cast.h> -*- C++ -*-
+
+// Copyright (C) 2008 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 2, 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.
+
+// You should have received a copy of the GNU General Public License
+// along with this library; see the file COPYING.  If not, write to
+// the Free Software Foundation, 51 Franklin Street, Fifth Floor,
+// Boston, MA 02110-1301, USA.
+
+// As a special exception, you may use this file as part of a free software
+// library without restriction.  Specifically, if other files instantiate
+// templates or use macros or inline functions from this file, or you compile
+// this file and link it with other files to produce an executable, this
+// file does not by itself cause the resulting executable to be covered by
+// the GNU General Public License.  This exception does not however
+// invalidate any other reasons why the executable file might be covered by
+// the GNU General Public License.
+
+#ifndef _EXT_CAST_
+#define _EXT_CAST_ 1
+
+_GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx);
+
+  /**
+   * 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
+
+#endif