File indexing completed on 2024-04-21 05:43:20

 /***************************************************************************
  *   Copyright (C) 2004-2005 by Daniel Clarke                              *
  *   daniel.jc@gmail.com                                               *
  *                                                                         *
  *   This program 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.                                   *
  *                                                                         *
  *   This program 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 this program; if not, write to the                         *
  *   Free Software Foundation, Inc.,                                       *
  *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
  ***************************************************************************/
 #ifndef TRAVERSER_H
 #define TRAVERSER_H
 
 #include "btreenode.h"
 
 /**
 Keeps persistant information needed and the algorithm for traversing the binary trees made of BTreeNodes, initialise either by passing a BTreeBase or BTreeNode to traverse a sub tree.
 
 Note that this is designed for traversing in the *reverse* way starting at the end of each branch
 in order to calculate the expression contained in the tree.
 
 @author Daniel Clarke
 */
 class Traverser
 {
 public:
     Traverser(BTreeNode *root);
     ~Traverser();
     
     /** Find where to start in the tree and return it also resets all the data related to the traversal. */
     BTreeNode *start();
     
     /** Finds the next node to move to and returns it. */
     BTreeNode *next();
     
     /** Returns true if we are on the left branch, false otherwise. */
     bool onLeftBranch();
     
     /** Returns the node on the opposite branch of the parent. */
     BTreeNode * oppositeNode();
     
     BTreeNode * current() const { return m_current; }
 
     void setCurrent(BTreeNode *current){m_current = current;}
     
     /** From the current position, go down the tree taking a left turn always, 
      and stopping when reaching the left terminal node.
      */
     void descendLeftwardToTerminal();
     
     /** It might occur in the future that next() does not just move to the parent,
      so use this for moving to parent
      */
     void moveToParent();
     
     BTreeNode *root() const {return m_root;}
     
 protected:
     BTreeNode *m_root;
     BTreeNode *m_current;
 };
 
 #endif