CascadedPolygonUnion.h

/**********************************************************************
 *
 * GEOS - Geometry Engine Open Source
 * http://geos.osgeo.org
 *
 * Copyright (C) 2011 Sandro Santilli <strk@kbt.io>
 * Copyright (C) 2006 Refractions Research 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: operation/union/CascadedPolygonUnion.java r487 (JTS-1.12+)
 * Includes custom code to deal with https://trac.osgeo.org/geos/ticket/837
 *
 **********************************************************************/
 
#ifndef GEOS_OP_UNION_CASCADEDPOLYGONUNION_H
#define GEOS_OP_UNION_CASCADEDPOLYGONUNION_H
 
#include <geos/export.h>
 
#include <vector>
#include <algorithm>
#include <memory>
 
#include "GeometryListHolder.h"
 
// Forward declarations
namespace geos {
namespace geom {
class GeometryFactory;
class Geometry;
class Polygon;
class MultiPolygon;
class Envelope;
}
namespace index {
namespace strtree {
class ItemsList;
}
}
}
 
namespace geos {
namespace operation { // geos::operation
namespace geounion {  // geos::operation::geounion
 
class GEOS_DLL CascadedPolygonUnion {
private:
    std::vector<geom::Polygon*>* inputPolys;
    geom::GeometryFactory const* geomFactory;
 
    static int const STRTREE_NODE_CAPACITY = 4;
 
    static std::unique_ptr<geom::Geometry> restrictToPolygons(std::unique_ptr<geom::Geometry> g);
 
public:
    CascadedPolygonUnion();
 
    static geom::Geometry* Union(std::vector<geom::Polygon*>* polys);
 
    template <class T>
    static geom::Geometry*
    Union(T start, T end)
    {
        std::vector<geom::Polygon*> polys;
        for(T i = start; i != end; ++i) {
            const geom::Polygon* p = dynamic_cast<const geom::Polygon*>(*i);
            polys.push_back(const_cast<geom::Polygon*>(p));
        }
        return Union(&polys);
    }
 
    static geom::Geometry* Union(const geom::MultiPolygon* polys);
 
    CascadedPolygonUnion(std::vector<geom::Polygon*>* polys)
        : inputPolys(polys),
          geomFactory(nullptr)
    {}
 
    geom::Geometry* Union();
 
private:
    geom::Geometry* unionTree(index::strtree::ItemsList* geomTree);
 
    geom::Geometry* binaryUnion(GeometryListHolder* geoms);
 
    geom::Geometry* binaryUnion(GeometryListHolder* geoms, std::size_t start,
                                std::size_t end);
 
    GeometryListHolder* reduceToGeometries(index::strtree::ItemsList* geomTree);
 
    geom::Geometry* unionSafe(geom::Geometry* g0, geom::Geometry* g1);
 
    static geom::Geometry* unionActual(geom::Geometry* g0, geom::Geometry* g1);
};
 
} // namespace geos::operation::union
} // namespace geos::operation
} // namespace geos
 
#endif