mirror of https://github.com/CGAL/cgal
88 lines
2.2 KiB
C++
88 lines
2.2 KiB
C++
// Copyright (c) 2000 Max-Planck-Institute Saarbruecken (Germany).
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// All rights reserved.
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//
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// This file is part of CGAL (www.cgal.org); you may redistribute it under
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// the terms of the Q Public License version 1.0.
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// See the file LICENSE.QPL distributed with CGAL.
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//
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// Licensees holding a valid commercial license may use this file in
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// accordance with the commercial license agreement provided with the software.
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//
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// This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
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// WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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//
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// $URL$
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// $Id$
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//
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//
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// Author(s) : Stefan Schirra
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// Andreas Fabri
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// Geert-Jan Giezeman
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// Michael Seel
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// Sylvain Pion
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// ======================================================================
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#ifndef CGAL_OBJECT_HANDLE_H
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#define CGAL_OBJECT_HANDLE_H
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#include <CGAL/Handle_for_virtual.h>
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#include <CGAL/circulator.h>
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CGAL_BEGIN_NAMESPACE
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template <class T>
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class Handle_wrapper : public Ref_counted_virtual
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{
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public:
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Handle_wrapper(const T& object) : _object(object) {}
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Handle_wrapper() {}
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operator T() const { return _object; }
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~Handle_wrapper() {}
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private:
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T _object;
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};
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class Object_handle
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: public Handle_for_virtual<Ref_counted_virtual>
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{
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struct empty{};
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typedef Handle_for_virtual<Ref_counted_virtual> base;
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public:
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Object_handle()
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{ initialize_with(Handle_wrapper<empty>()); }
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template <class T>
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Object_handle(const T&t)
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{ initialize_with(Handle_wrapper<T>(t)); }
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template <class T>
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bool assign(T &t) const
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{
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const Handle_wrapper<T> *wp =
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dynamic_cast<const Handle_wrapper<T> *>(Ptr());
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if ( wp == static_cast<Handle_wrapper<T> *>(0) )
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return false;
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t = *(wp);
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return true;
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}
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bool is_empty() const
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{ empty E; return assign(E); }
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bool operator==(CGAL_NULL_TYPE n) const
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{ CGAL_assertion(n == 0); return is_empty(); }
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bool operator!=(CGAL_NULL_TYPE n) const
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{ CGAL_assertion(n == 0); return !is_empty(); }
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};
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template <class T>
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inline bool assign(T& t, const Object_handle& o)
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{ return o.assign(t); }
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CGAL_END_NAMESPACE
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#endif // CGAL_OBJECT_HANDLE_H
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