index/chain/MonotoneChain.h

/**********************************************************************
 *
 * GEOS - Geometry Engine Open Source
 * http://geos.osgeo.org
 *
 * 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.
 *
 **********************************************************************
 *
 * Last port: index/chain/MonotoneChain.java rev. 1.15 (JTS-1.10)
 *
 **********************************************************************/
 
#ifndef GEOS_IDX_CHAIN_MONOTONECHAIN_H
#define GEOS_IDX_CHAIN_MONOTONECHAIN_H
 
#include <geos/export.h>
#include <geos/geom/CoordinateSequence.h> // for inline
#include <geos/geom/Envelope.h> // for inline
#include <geos/geom/LineSegment.h> // for inline
 
#include <memory> // for unique_ptr
 
// Forward declarations
namespace geos {
namespace geom {
class LineSegment;
class CoordinateSequence;
}
namespace index {
namespace chain {
class MonotoneChainSelectAction;
class MonotoneChainOverlapAction;
}
}
}
 
namespace geos {
namespace index { // geos::index
namespace chain { // geos::index::chain
 
class GEOS_DLL MonotoneChain {
public:
 
    MonotoneChain(const geom::CoordinateSequence& pts,
                  std::size_t start, std::size_t end, void* context);
 
    ~MonotoneChain() = default;
 
    const geom::Envelope& getEnvelope() const;
    const geom::Envelope& getEnvelope(double expansionDistance) const;
 
    size_t
    getStartIndex() const
    {
        return start;
    }
 
    size_t
    getEndIndex() const
    {
        return end;
    }
 
    void getLineSegment(std::size_t index, geom::LineSegment& ls) const {
        pts->getAt(index, ls.p0);
        pts->getAt(index + 1, ls.p1);
    }
 
    std::unique_ptr<geom::CoordinateSequence> getCoordinates() const;
 
    void select(const geom::Envelope& searchEnv,
                MonotoneChainSelectAction& mcs) const;
 
    void computeOverlaps(const MonotoneChain* mc,
                         MonotoneChainOverlapAction* mco) const;
 
    void computeOverlaps(const MonotoneChain* mc, double overlapTolerance,
                         MonotoneChainOverlapAction* mco) const;
 
    void*
    getContext() const
    {
        return context;
    }
 
private:
 
    void computeSelect(const geom::Envelope& searchEnv,
                       std::size_t start0,
                       std::size_t end0,
                       MonotoneChainSelectAction& mcs) const;
 
    void computeOverlaps(std::size_t start0, std::size_t end0, const MonotoneChain& mc,
                         std::size_t start1, std::size_t end1,
                         double overlapTolerance,
                         MonotoneChainOverlapAction& mco) const;
 
    bool overlaps(std::size_t start0, std::size_t end0,
                  const MonotoneChain& mc, std::size_t start1, std::size_t end1,
                  double overlapTolerance) const {
        if (overlapTolerance > 0.0) {
            return overlaps(pts->getAt(start0), pts->getAt(end0),
                            mc.pts->getAt(start1), mc.pts->getAt(end1), overlapTolerance);
        }
        return geom::Envelope::intersects(pts->getAt(start0), pts->getAt(end0),
                                          mc.pts->getAt(start1), mc.pts->getAt(end1));
    }
 
    static bool overlaps(const geom::Coordinate& p1, const geom::Coordinate& p2,
                  const geom::Coordinate& q1, const geom::Coordinate& q2,
                  double overlapTolerance);
 
    const geom::CoordinateSequence* pts;
 
    void* context;
 
    std::size_t start;
 
    std::size_t end;
 
    mutable geom::Envelope env;
};
 
} // namespace geos::index::chain
} // namespace geos::index
} // namespace geos
 
#endif // GEOS_IDX_CHAIN_MONOTONECHAIN_H