/**********************************************************************
 *
 * GEOS - Geometry Engine Open Source
 * http://geos.osgeo.org
 *
 * Copyright (C) 2005-2006 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 Public Licence as published
 * by the Free Software Foundation. 
 * See the COPYING file for more information.
 *
 **********************************************************************/

#include <vector>

#include <geos/geomgraph/index/MonotoneChainIndexer.h>
#include <geos/geom/Coordinate.h>
#include <geos/geom/CoordinateSequence.h>
#include <geos/geomgraph/Quadrant.h>

using namespace std;
using namespace geos::geom;

namespace geos {
namespace geomgraph { // geos.geomgraph
namespace index { // geos.geomgraph.index

void
MonotoneChainIndexer::getChainStartIndices(const CoordinateSequence* pts,
	vector<int> &startIndexList)
{
	// find the startpoint (and endpoints) of all monotone chains
	// in this edge
	int start=0;
	//vector<int>* startIndexList=new vector<int>();
	startIndexList.push_back(start);
	do {
		int last=findChainEnd(pts,start);
		startIndexList.push_back(last);
		start=last;
	} while(start<(int)pts->getSize()-1);
	// copy list to an array of ints, for efficiency
	//return startIndexList;
}

/**
* @return the index of the last point in the monotone chain
*/
int MonotoneChainIndexer::findChainEnd(const CoordinateSequence* pts,int start){
	// determine quadrant for chain
	int chainQuad=Quadrant::quadrant(pts->getAt(start),pts->getAt(start + 1));
	int last=start+1;
	while(last<(int)pts->getSize()) {
		// compute quadrant for next possible segment in chain
		int quad=Quadrant::quadrant(pts->getAt(last - 1),pts->getAt(last));
		if (quad!=chainQuad) break;
		last++;
	}
	return last-1;
}

} // namespace geos.geomgraph.index
} // namespace geos.geomgraph
} // namespage geos