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diff --git a/helm/DEVEL/mathml_editor/src/Ptr.hh b/helm/DEVEL/mathml_editor/src/Ptr.hh
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+++ b/helm/DEVEL/mathml_editor/src/Ptr.hh
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+// Copyright (C) 2000-2002, Luca Padovani <luca.padovani@cs.unibo.it>.
+//
+// This file is part of GtkMathView, a Gtk widget for MathML.
+// 
+// GtkMathView 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
+// of the License, or (at your option) any later version.
+//
+// GtkMathView 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 GtkMathView; if not, write to the Free Software
+// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+// 
+// For details, see the GtkMathView World-Wide-Web page,
+// http://www.cs.unibo.it/helm/mml-widget, or send a mail to
+// <luca.padovani@cs.unibo.it>
+
+#ifndef Ptr_hh
+#define Ptr_hh
+
+template <class P>
+class Ptr
+{
+public:
+  Ptr(P* p = 0) : ptr(p) { if (ptr != 0) ptr->ref(); }
+  Ptr(const Ptr& p) : ptr(p.ptr) { if (ptr != 0) ptr->ref(); }
+  ~Ptr() { if (ptr != 0) ptr->unref(); }
+
+  P* operator->() const { assert(ptr != 0); return ptr; }
+  Ptr& operator=(const Ptr& p)
+  { 
+    if (ptr == p.ptr) return *this;
+    if (p.ptr != 0) p.ptr->ref();
+    if (ptr != 0) ptr->unref();
+    ptr = p.ptr;
+    return *this;
+  }
+
+  operator P*() const { return ptr; }
+  template <class Q> friend Ptr<Q> smart_cast(const Ptr& p) { return Ptr<Q>(dynamic_cast<Q*>(p.ptr)); }  
+  template <class Q> friend bool is_a(const Ptr& p) { return dynamic_cast<Q*>(p.ptr) != 0; }
+  template <class Q> operator Ptr<Q>() const { return Ptr<Q>(ptr); }
+
+private:
+  P* ptr;
+};
+
+#endif // Ptr_hh