code/validation/C++/0025059_IteratedNoder.cpp

/**********************************************************************
 *
 * GEOS - Geometry Engine Open Source
 * http://geos.osgeo.org
 *
 * Copyright (C) 2006 Refractions Research Inc.
 * 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.
 *
 **********************************************************************
 *
 * Last port: noding/IteratedNoder.java r591 (JTS-1.12+)
 *
 **********************************************************************/

#include <sstream>
#include <vector>

#include <geos/profiler.h>
#include <geos/util/TopologyException.h> 
#include <geos/noding/IteratedNoder.h>
#include <geos/noding/SegmentString.h>
#include <geos/noding/MCIndexNoder.h>
#include <geos/noding/IntersectionAdder.h>

#ifndef GEOS_DEBUG
#define GEOS_DEBUG 0
#endif

using namespace std;
using namespace geos::geom;

namespace geos {
namespace noding { // geos.noding

/* private */
void
IteratedNoder::node(vector<SegmentString*> *segStrings,
		int *numInteriorIntersections)
{
	IntersectionAdder si(li);
	MCIndexNoder noder;
	noder.setSegmentIntersector(&si);
	noder.computeNodes(segStrings);
	nodedSegStrings = noder.getNodedSubstrings();
	*numInteriorIntersections = si.numInteriorIntersections;
//System.out.println("# intersection tests: " + si.numTests);
}

/* public */
void
IteratedNoder::computeNodes(SegmentString::NonConstVect* segStrings)
	// throw(GEOSException);
{
	int numInteriorIntersections;
	nodedSegStrings = segStrings;
	int nodingIterationCount = 0;
	int lastNodesCreated = -1;
	vector<SegmentString*> *lastStrings = 0;
	do {

		// NOTE: will change this.nodedSegStrings
		node(nodedSegStrings, &numInteriorIntersections);

		// Delete noded strings from previous iteration
		if ( lastStrings ) {
			for ( unsigned int i = 0, n = lastStrings->size(); i < n; ++i )
				delete (*lastStrings)[i];
			delete lastStrings;
		}
		lastStrings = nodedSegStrings;

		nodingIterationCount++;
		int nodesCreated = numInteriorIntersections;

		/**
		 * Fail if the number of nodes created is not declining.
		 * However, allow a few iterations at least before doing this
		 */
		//cerr<<"# nodes created: "<<nodesCreated<<endl;
		if (lastNodesCreated > 0
				&& nodesCreated >= lastNodesCreated
				&& nodingIterationCount > maxIter)
		{
			stringstream s;
			s<<"Iterated noding failed to converge after "<<
                                    nodingIterationCount << " iterations";
			throw util::TopologyException(s.str());
		}
		lastNodesCreated = nodesCreated;

	} while (lastNodesCreated > 0);
	//cerr<<"# nodings = "<<nodingIterationCount<<endl;
}


} // namespace geos.noding
} // namespace geos