text: /**********************************************************************
   *
   * 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.
   *
   **********************************************************************/
  
  #ifndef GEOS_GEOMGRAPH_INDEX_SIMPLESWEEPLINEINTERSECTOR_H
  #define GEOS_GEOMGRAPH_INDEX_SIMPLESWEEPLINEINTERSECTOR_H
  
  #include <geos/export.h>
  #include <vector>
  
  #include <geos/geomgraph/index/EdgeSetIntersector.h> // for inheritance
  
  #ifdef _MSC_VER
  #pragma warning(push)
  #pragma warning(disable: 4251) // warning C4251: needs to have dll-interface to be used by clients of class
  #endif
  
  // Forward declarations
  namespace geos {
  	namespace geomgraph {
  		class Edge;
  		namespace index {
  			class SegmentIntersector;
  			class SweepLineEvent;
  		}
  	}
  }
  
  namespace geos {
  namespace geomgraph { // geos::geomgraph
  namespace index { // geos::geomgraph::index
  
  /** \brief
   * Finds all intersections in one or two sets of edges,
   * using a simple x-axis sweepline algorithm.
   *
   * While still O(n^2) in the worst case, this algorithm
   * drastically improves the average-case time.
   */
  class GEOS_DLL SimpleSweepLineIntersector: public EdgeSetIntersector {
  
  public:
  
  	SimpleSweepLineIntersector();
  
  	~SimpleSweepLineIntersector() override;
  
  	void computeIntersections(std::vector<Edge*> *edges,
  			SegmentIntersector *si,
  			bool testAllSegments) override;
  
  	void computeIntersections(std::vector<Edge*> *edges0,
  			std::vector<Edge*> *edges1,
  			SegmentIntersector *si) override;
  
  private:
  
  	void add(std::vector<Edge*> *edges);
  
  	std::vector<SweepLineEvent*> events;
  
  	// statistics information
  	int nOverlaps;
  
  	void add(std::vector<Edge*> *edges, void* edgeSet);
  
  	void add(Edge *edge,void* edgeSet);
  
  	void prepareEvents();
  
  	void computeIntersections(SegmentIntersector *si);
  
  	void processOverlaps(int start, int end, SweepLineEvent *ev0,
  			SegmentIntersector *si);
  };
  
  } // namespace geos.geomgraph.index
  } // namespace geos.geomgraph
  } // namespace geos
  
  #ifdef _MSC_VER
  #pragma warning(pop)
  #endif
  
  #endif // GEOS_GEOMGRAPH_INDEX_SIMPLESWEEPLINEINTERSECTOR_H
  
  