LineDissolver.h

/**********************************************************************
 *
 * GEOS - Geometry Engine Open Source
 * http://geos.osgeo.org
 *
 * Copyright (c) 2025 Martin Davis
 * Copyright (C) 2025 Paul Ramsey <pramsey@cleverelephant.ca>
 *
 * 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/dissolve/DissolveEdgeGraph.h>
// #include <memory>
// #include <vector>
// #include <stack>
#include <geos/geom/LineString.h>
#include <geos/export.h>
 
 
// Forward declarations
namespace geos {
namespace dissolve {
    class DissolveHalfEdge;
}
namespace edgegraph {
    class HalfEdge;
}
namespace geom {
    class CoordinateSequence;
    class Geometry;
    class GeometryFactory;
    // class LineString;
}
}
 
 
namespace geos {      // geos.
namespace dissolve {  // geos.dissolve
 

class GEOS_DLL LineDissolver {
 
    using CoordinateSequence = geos::geom::CoordinateSequence;
    using Geometry = geos::geom::Geometry;
    using GeometryFactory = geos::geom::GeometryFactory;
    using LineString = geos::geom::LineString;
    using HalfEdge = geos::edgegraph::HalfEdge;
 
private:
 
    std::unique_ptr<Geometry> result;
    const GeometryFactory* factory = nullptr;
    DissolveEdgeGraph graph;
    std::vector<std::unique_ptr<LineString>> lines;
    std::stack<HalfEdge*> nodeEdgeStack;
    DissolveHalfEdge* ringStartEdge = nullptr;
 
 
    void computeResult();
 
    void process(HalfEdge* e);

    void stackEdges(HalfEdge* node);

    void buildLines();

    void updateRingStartEdge(DissolveHalfEdge* e);

    void buildLine(HalfEdge* eStart);
 
    void buildRing(HalfEdge* eStartRing);
 
    void addLine(std::unique_ptr<CoordinateSequence>& cs);
 
 
public:
 
    LineDissolver() : result(nullptr) {};

    static std::unique_ptr<Geometry> dissolve(const Geometry* g);

    void add(const Geometry* geometry);

    void add(std::vector<const Geometry*> geometries);
 
    void add(const LineString* lineString);

    std::unique_ptr<Geometry> getResult();

    LineDissolver(const LineDissolver&) = delete;
    LineDissolver& operator=(const LineDissolver&) = delete;
 
 
};
 
} // namespace geos.dissolve
} // namespace geos