CoverageRingEdges.h

/**********************************************************************
 *
 * GEOS - Geometry Engine Open Source
 * http://geos.osgeo.org
 *
 * Copyright (C) 2023 Paul Ramsey <pramsey@cleverelephant.ca>
 * Copyright (c) 2023 Martin Davis.
 *
 * 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.
 *
 **********************************************************************/

#pragma once

#include <geos/geom/Coordinate.h>
#include <geos/geom/LineSegment.h>
#include <geos/coverage/CoverageEdge.h> // to materialize CoverageEdge

#include <set>
#include <map>

// Forward declarations
namespace geos {
namespace geom {
class CoordinateSequence;
class Geometry;
class LinearRing;
class MultiPolygon;
class Polygon;
}
namespace coverage {
class CoverageEdge;
}
}

using geos::geom::Coordinate;
using geos::geom::CoordinateSequence;
using geos::geom::Geometry;
using geos::geom::LinearRing;
using geos::geom::LineSegment;
using geos::geom::MultiPolygon;
using geos::geom::Polygon;

namespace geos {     // geos
namespace coverage { // geos.coverage

class GEOS_DLL CoverageRingEdges {

private:

    // Members
    const std::vector<const Geometry*>& m_coverage;
    std::map<const LinearRing*, std::vector<CoverageEdge*>> m_ringEdgesMap;
    std::vector<CoverageEdge*> m_edges;
    std::vector<std::unique_ptr<CoverageEdge>> m_edgeStore;

    /* Turn off copy constructors for MSVC */
    CoverageRingEdges(const CoverageRingEdges&) = delete;
    CoverageRingEdges& operator=(const CoverageRingEdges&) = delete;

public:

    CoverageRingEdges(const std::vector<const Geometry*>& coverage)
        : m_coverage(coverage)
    {
        build();
    };


    std::vector<CoverageEdge*>& getEdges()
    {
        return m_edges;
    };

    std::vector<CoverageEdge*> selectEdges(
        std::size_t ringCount) const;

    std::vector<std::unique_ptr<Geometry>> buildCoverage() const;


private:

    void build();

    void addRingEdges(
        const LinearRing* ring,
        Coordinate::UnorderedSet& nodes,
        LineSegment::UnorderedSet& boundarySegs,
        std::map<LineSegment, CoverageEdge*>& uniqueEdgeMap);

    void addBoundaryInnerNodes(
        const LinearRing* ring,
        LineSegment::UnorderedSet& boundarySegs,
        Coordinate::UnorderedSet& nodes);

    std::vector<CoverageEdge*> extractRingEdges(
        const LinearRing* ring,
        std::map<LineSegment, CoverageEdge*>& uniqueEdgeMap,
        Coordinate::UnorderedSet& nodes);

    CoverageEdge* createEdge(
        const CoordinateSequence& ring,
        std::map<LineSegment, CoverageEdge*>& uniqueEdgeMap);

    CoverageEdge* createEdge(
        const CoordinateSequence& ring,
        std::size_t start, std::size_t end,
        std::map<LineSegment, CoverageEdge*>& uniqueEdgeMap);

    std::size_t findNextNodeIndex(
        const CoordinateSequence& ring,
        std::size_t start,
        Coordinate::UnorderedSet& nodes) const;

    static std::size_t next(
        std::size_t index,
        const CoordinateSequence& ring);

    Coordinate::UnorderedSet findMultiRingNodes(
        const std::vector<const Geometry*>& coverage);

    Coordinate::UnorderedSet findBoundaryNodes(
        LineSegment::UnorderedSet& lineSegments);

    std::unique_ptr<Geometry> buildPolygonal(
        const Geometry* geom) const;

    std::unique_ptr<Geometry> buildMultiPolygon(
        const MultiPolygon* geom) const;

    std::unique_ptr<Polygon> buildPolygon(
        const Polygon* polygon) const;

    std::unique_ptr<LinearRing> buildRing(
        const LinearRing* ring) const;

    bool isEdgeDirForward(
        const std::vector<CoverageEdge*>& ringEdges,
        std::size_t index,
        const Coordinate& prevPt) const;


};

} // namespace geos.coverage
} // namespace geos