/**********************************************************************
 * $Id: planarEdge.cpp,v 1.3 2004/10/13 10:03:02 strk Exp $
 *
 * GEOS - Geometry Engine Open Source
 * http://geos.refractions.net
 *
 * Copyright (C) 2001-2002 Vivid Solutions Inc.
 *
 * This is free software; you can redistribute and/or modify it under
 * the terms of the GNU Lesser General Licence as published
 * by the Free Software Foundation. 
 * See the COPYING file for more information.
 *
 **********************************************************************
 * $Log: planarEdge.cpp,v $
 * Revision 1.3  2004/10/13 10:03:02  strk
 * Added missing linemerge and polygonize operation.
 * Bug fixes and leaks removal from the newly added modules and
 * planargraph (used by them).
 * Some comments and indentation changes.
 *
 * Revision 1.2  2004/07/02 13:28:29  strk
 * Fixed all #include lines to reflect headers layout change.
 * Added client application build tips in README.
 *
 * Revision 1.1  2004/04/04 06:29:11  ybychkov
 * "planargraph" and "geom/utill" upgraded to JTS 1.4
 *
 *
 **********************************************************************/


#include <geos/planargraph.h>

namespace geos {
//namespace planargraph {

/**
* Constructs an Edge whose DirectedEdges are not yet set. Be sure to call
* {@link #setDirectedEdges(DirectedEdge, DirectedEdge)}
*/
planarEdge::planarEdge(): dirEdge()
{
}

/**
* Constructs an Edge initialized with the given DirectedEdges, and for each
* DirectedEdge: sets the Edge, sets the symmetric DirectedEdge, and adds
* this Edge to its from-Node.
*/
planarEdge::planarEdge(planarDirectedEdge *de0, planarDirectedEdge *de1){
	setDirectedEdges(de0, de1);
}

/*
 * Initializes this Edge's two DirectedEdges, and for each DirectedEdge:
 *  sets the Edge,
 *  sets the symmetric DirectedEdge, and
 *  adds this Edge to its from-Node.
 */
void
planarEdge::setDirectedEdges(planarDirectedEdge *de0, planarDirectedEdge *de1){
	dirEdge.push_back(de0);
	dirEdge.push_back(de1);
	de0->setEdge(this);
	de1->setEdge(this);
	de0->setSym(de1);
	de1->setSym(de0);
	de0->getFromNode()->addOutEdge(de0);
	de1->getFromNode()->addOutEdge(de1);
}

/**
* Returns one of the DirectedEdges associated with this Edge.
* @param i 0 or 1
*/
planarDirectedEdge *
planarEdge::getDirEdge(int i)
{
	return dirEdge[i];
}

/*
 * Returns the DirectedEdge that starts from the given node, or null if the
 * node is not one of the two nodes associated with this Edge.
 */
planarDirectedEdge *
planarEdge::getDirEdge(planarNode *fromNode)
{
	if (dirEdge[0]->getFromNode()==fromNode) return dirEdge[0];
	if (dirEdge[1]->getFromNode()==fromNode) return dirEdge[1];
	// node not found
	// possibly should throw an exception here?
	return NULL;
}

/**
* If <code>node</code> is one of the two nodes associated with this Edge,
* returns the other node; otherwise returns null.
*/
planarNode*
planarEdge::getOppositeNode(planarNode *node)
{
	if (dirEdge[0]->getFromNode()==node) return dirEdge[0]->getToNode();
	if (dirEdge[1]->getFromNode()==node) return dirEdge[1]->getToNode();
	// node not found
	// possibly should throw an exception here?
	return NULL;
}

//} // namespace planargraph
} // namespace geos