Add an utility to iterate on nodes in the order of increasing ids

-  SMDS_NodeIteratorPtr nodesIterator() const;
+  SMDS_NodeIteratorPtr nodesIterator(bool idInceasingOrder=false) const;

src/SMDS/SMDS_Mesh.cxx

@@ -2129,6 +2129,8 @@ void SMDS_Mesh::setInverseElements(bool b)
   myHasInverseElements=b;
 }
 
+namespace {
+
   ///////////////////////////////////////////////////////////////////////////////
   ///Iterator on NCollection_Map
   ///////////////////////////////////////////////////////////////////////////////
@@ -2157,18 +2159,51 @@ struct MYNCollection_Map_Iterator: public FATHER
       return current;
     }
   };
+  //================================================================================
+  /*!
+   * \brief Iterator on elements in id increasing order
+   */
+  //================================================================================
+
+  template <typename ELEM=const SMDS_MeshElement*>
+  class IdSortedIterator : public SMDS_Iterator<ELEM>
+  {
+    const SMDS_MeshElementIDFactory& myIDFact;
+    int                              myID, myMaxID;
+    ELEM                             myElem;
+
+  public:
+    IdSortedIterator(const SMDS_MeshElementIDFactory& fact)
+      :myIDFact( fact ), myID(1), myMaxID( myIDFact.GetMaxID() ), myElem(0)
+    {
+      next();
+    }
+    bool more()
+    {
+      return myElem;
+    }
+    ELEM next()
+    {
+      ELEM current = myElem;
+      for ( myElem = 0; myID <= myMaxID && !myElem; ++myID )
+        myElem = (ELEM) myIDFact.MeshElement( myID );
+      return current;
+    }
+  };
+}
 
 ///////////////////////////////////////////////////////////////////////////////
 /// Return an iterator on nodes of the current mesh factory
 ///////////////////////////////////////////////////////////////////////////////
 
-SMDS_NodeIteratorPtr SMDS_Mesh::nodesIterator() const
+SMDS_NodeIteratorPtr SMDS_Mesh::nodesIterator(bool idInceasingOrder) const
 {
-  //return SMDS_NodeIteratorPtr
-  //  (new SMDS_Mesh_MyNodeIterator(myNodeIDFactory->elementsIterator()));
   typedef MYNCollection_Map_Iterator
     < SetOfNodes, const SMDS_MeshNode*, SMDS_NodeIterator > TIterator;
-  return SMDS_NodeIteratorPtr(new TIterator(myNodes));
+  typedef IdSortedIterator< const SMDS_MeshNode* >          TSortedIterator;
+  return ( idInceasingOrder ?
+           SMDS_NodeIteratorPtr( new TSortedIterator( *myNodeIDFactory )) :
+           SMDS_NodeIteratorPtr( new TIterator(myNodes)));
 }
 
 ///////////////////////////////////////////////////////////////////////////////

src/SMDS/SMDS_Mesh.hxx

@@ -47,7 +47,7 @@ public:
 
   SMDS_Mesh();
 
-  SMDS_NodeIteratorPtr nodesIterator() const;
+  SMDS_NodeIteratorPtr nodesIterator(bool idInceasingOrder=false) const;
   SMDS_0DElementIteratorPtr elements0dIterator() const;
   SMDS_EdgeIteratorPtr edgesIterator() const;
   SMDS_FaceIteratorPtr facesIterator() const;