mirror of https://github.com/CGAL/cgal
182 lines
3.7 KiB
C++
182 lines
3.7 KiB
C++
// Copyright (c) 2000 Utrecht University (The Netherlands),
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// ETH Zurich (Switzerland), Freie Universitaet Berlin (Germany),
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// INRIA Sophia-Antipolis (France), Martin-Luther-University Halle-Wittenberg
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// (Germany), Max-Planck-Institute Saarbruecken (Germany), RISC Linz (Austria),
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// and Tel-Aviv University (Israel). All rights reserved.
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//
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// This file is part of CGAL (www.cgal.org); you can redistribute it and/or
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// modify it under the terms of the GNU Lesser General Public License as
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// published by the Free Software Foundation; version 2.1 of the License.
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// See the file LICENSE.LGPL 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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#ifndef CGAL_OBJECT_H
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#define CGAL_OBJECT_H
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#include <CGAL/basic.h>
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#include <CGAL/Handle_for_virtual.h>
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#include <typeinfo>
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CGAL_BEGIN_NAMESPACE
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template <class T>
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class Wrapper : public Ref_counted_virtual
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{
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public:
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Wrapper(const T& object) : _object(object) {}
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Wrapper() {}
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operator T() const { return _object; }
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~Wrapper() {}
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virtual const std::type_info & type() const
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{
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return typeid(T);
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}
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virtual const void * object_ptr() const
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{
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return & _object;
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}
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private:
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T _object;
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};
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class Object
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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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struct private_tag{};
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Object()
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{
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initialize_with(Wrapper<empty>());
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}
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template <class T>
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Object(const T&t, private_tag)
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{
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initialize_with(Wrapper<T>(t));
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}
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template <class T>
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bool assign(T &t) const
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{
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#ifdef _MSC_VER
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try {
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#endif
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const Wrapper<T> *wp = dynamic_cast<const Wrapper<T> *>(Ptr());
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if (wp == NULL)
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return false;
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t = *wp;
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#ifdef _MSC_VER
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}
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catch (...) {
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std::cerr << "ERROR : YOUR COMPILER MUST SUPPORT RTTI" << std::endl;
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abort();
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}
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#endif
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return true;
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}
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bool
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is_empty() const
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{
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empty E;
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return assign(E);
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}
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const std::type_info & type() const
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{
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return is_empty() ? typeid(void) : Ptr()->type();
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}
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};
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template <class T>
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inline
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Object
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make_object(const T& t)
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{
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return Object(t, Object::private_tag());
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}
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template <class T>
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inline
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bool
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assign(T& t, const Object& o)
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{
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return o.assign(t);
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}
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struct Bad_object_cast
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: public std::bad_cast
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{
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virtual const char * what() const throw()
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{
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return "CGAL::bad_object_cast: "
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"failed conversion using CGAL::object_cast";
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}
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};
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/*
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template <class T>
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inline
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T * object_cast(Object * o)
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{
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return o && o->type() == typeid(T) ? o->object_ptr() : NULL;
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}
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*/
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template <class T>
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inline
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const T * object_cast(const Object * o)
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{
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const Wrapper<T> *wp = dynamic_cast<const Wrapper<T> *>(o->Ptr());
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if (wp == NULL)
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return NULL;
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return static_cast<const T*>(wp->object_ptr());
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// return o && o->type() == typeid(T)
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// ? static_cast<const T*>(o->object_ptr())
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// : NULL;
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}
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template <class T>
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inline
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T object_cast(const Object & o)
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{
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const T * result = object_cast<T>(&o);
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if (!result)
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throw Bad_object_cast();
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return *result;
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}
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CGAL_END_NAMESPACE
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#endif // CGAL_OBJECT_H
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