Autopointer class as used in ALU3dGrid

[[Imported from SVN: r2122]]

common/autoptr.hh

+// -*- tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+// vi: set et ts=4 sw=2 sts=2:
+#ifndef DUNE_AUTOPTR_HH
+#define DUNE_AUTOPTR_HH
+
+namespace Dune {
+  /** \brief An auto pointer class */
+  template <class Pointer>
+  class AutoPointer
+  {
+    //! Pointer to Object
+    Pointer * ptr_;
+
+    //! number of copies that exist from this Object
+    mutable int *refCount_;
+
+    //! true if we own the pointer
+    mutable bool owner_;
+
+  public:
+    //! if a copy is made, the refcount is increased
+    inline AutoPointer(const AutoPointer<Pointer> & copy)
+    {
+      ptr_ = 0;
+      refCount_ = 0;
+      if(copy.ptr_)
+      {
+        ptr_ = copy.ptr_;
+        refCount_ = copy.refCount_;
+        (*refCount_)++;
+        // now we own the pointer
+        owner_ = true;
+        copy.owner_ = false;
+      }
+    }
+
+    //! initialize the member variables
+    AutoPointer() : ptr_ (0) , refCount_ (0) , owner_(false) {}
+
+    // store object pointer and create refCount
+    void store (Pointer * ptr)
+    {
+      assert(ptr_ == 0);
+      ptr_ = ptr;
+      if(ptr_)
+      {
+        int * tmp = new int;
+        refCount_ = tmp;
+        (*refCount_) = 1;
+        owner_ = true;
+      }
+    }
+
+    //! set Stack free, if no more refences exist
+    ~AutoPointer()
+    {
+      if(refCount_ && ptr_)
+      {
+        (*refCount_)--;
+        if((*refCount_) <= 0)
+        {
+          if(ptr_) delete  ptr_;
+          if(refCount_) delete refCount_;
+          owner_ = false;
+        }
+      }
+    }
+
+    //! return object reference
+    Pointer & operator * () const
+    {
+      assert(ptr_ != 0);
+      assert(owner_);
+      return *ptr_;
+    }
+
+    //! return object pointer
+    Pointer * operator -> () const
+    {
+      assert(ptr_ != 0);
+      assert(owner_);
+      return ptr_;
+    }
+
+  private:
+    //! if copy is made than one more Reference exists
+    AutoPointer<Pointer> & operator = (const AutoPointer<Pointer> & copy)
+    {
+      assert(false);
+      return (*this);
+    }
+  };
+} // end namespace Dune
+#endif