Logo Search packages:      
Sourcecode: ktechlab version File versions

traverser.h

/***************************************************************************
 *   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
*/
00033 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

Generated by  Doxygen 1.6.0   Back to index