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/***************************************************************************
* 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., *
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, 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
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