Introduce ArrayKernel::clean_keep_reservation().

src/OpenMesh/Core/Mesh/ArrayKernel.cc

@@ -177,6 +177,16 @@ void ArrayKernel::garbage_collection(bool _v, bool _e, bool _f)
   garbage_collection( empty_vh,empty_hh,empty_fh,_v, _e, _f);
 }
 
+void ArrayKernel::clean_keep_reservation()
+{
+    vertices_.clear();
+
+    edges_.clear();
+
+    faces_.clear();
+
+}
+
 void ArrayKernel::clean()
 {
 

src/OpenMesh/Core/Mesh/ArrayKernel.hh

@@ -306,6 +306,14 @@ public:
    */
   void clean();
 
+  /** \brief Reset the whole mesh
+   *
+   *  This will remove all elements from the mesh but keeps the properties.
+   *  In contrast to clean() the memory used for the elements will remain
+   *  allocated.
+   */
+  void clean_keep_reservation();
+
   // --- number of items ---
   size_t n_vertices()  const { return vertices_.size(); }
   size_t n_halfedges() const { return 2*edges_.size(); }