UnaryUnionOp.h

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/**********************************************************************
 *
 * GEOS - Geometry Engine Open Source
 * http://geos.osgeo.org
 *
 * Copyright (C) 2011 Sandro Santilli <strk@kbt.io>
 *
 * 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/UnaryUnionOp.java r320 (JTS-1.12)
 *
 **********************************************************************/

#ifndef GEOS_OP_UNION_UNARYUNION_H
#define GEOS_OP_UNION_UNARYUNION_H

#include <memory>
#include <vector>

#include <geos/export.h>
#include <geos/geom/GeometryFactory.h>
#include <geos/geom/Point.h>
#include <geos/geom/LineString.h>
#include <geos/geom/Polygon.h>
#include <geos/geom/util/GeometryExtracter.h>
#include <geos/operation/overlay/OverlayOp.h>
#include <geos/operation/union/CascadedPolygonUnion.h>
//#include <geos/operation/overlay/snap/SnapIfNeededOverlayOp.h>

#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 geom {
class GeometryFactory;
class Geometry;
}
}

namespace geos {
namespace operation { // geos::operation
namespace geounion {  // geos::operation::geounion

class GEOS_DLL UnaryUnionOp {
public:

    template <typename T>
    static std::unique_ptr<geom::Geometry>
    Union(const T& geoms)
    {
        UnaryUnionOp op(geoms);
        return op.Union();
    }

    template <class T>
    static std::unique_ptr<geom::Geometry>
    Union(const T& geoms,
          geom::GeometryFactory& geomFact)
    {
        UnaryUnionOp op(geoms, geomFact);
        return op.Union();
    }

    static std::unique_ptr<geom::Geometry>
    Union(const geom::Geometry& geom)
    {
        UnaryUnionOp op(geom);
        return op.Union();
    }

    template <class T>
    UnaryUnionOp(const T& geoms, geom::GeometryFactory& geomFactIn)
        : geomFact(&geomFactIn)
        , unionFunction(&defaultUnionFunction)
    {
        extractGeoms(geoms);
    }

    template <class T>
    UnaryUnionOp(const T& geoms)
        : geomFact(nullptr)
        , unionFunction(&defaultUnionFunction)
    {
        extractGeoms(geoms);
    }

    UnaryUnionOp(const geom::Geometry& geom)
        : geomFact(geom.getFactory())
        , unionFunction(&defaultUnionFunction)
    {
        extract(geom);
    }

    void setUnionFunction(UnionStrategy* unionFun)
    {
        unionFunction = unionFun;
    }

    std::unique_ptr<geom::Geometry> Union();

private:

    template <typename T>
    void
    extractGeoms(const T& geoms)
    {
        for(typename T::const_iterator
                i = geoms.begin(),
                e = geoms.end();
                i != e;
                ++i) {
            const geom::Geometry* geom = *i;
            extract(*geom);
        }
    }

    void
    extract(const geom::Geometry& geom)
    {
        using namespace geom::util;

        if(! geomFact) {
            geomFact = geom.getFactory();
        }

        GeometryExtracter::extract<geom::Polygon>(geom, polygons);
        GeometryExtracter::extract<geom::LineString>(geom, lines);
        GeometryExtracter::extract<geom::Point>(geom, points);
    }

    std::unique_ptr<geom::Geometry>
    unionNoOpt(const geom::Geometry& g0)
    {
        using geos::operation::overlay::OverlayOp;
        //using geos::operation::overlay::snap::SnapIfNeededOverlayOp;

        if(! empty.get()) {
            empty = geomFact->createEmptyGeometry();
        }
        //return SnapIfNeededOverlayOp::overlayOp(g0, *empty, OverlayOp::opUNION);
        return unionFunction->Union(&g0, empty.get());
    }

    std::unique_ptr<geom::Geometry> unionWithNull(
        std::unique_ptr<geom::Geometry> g0,
        std::unique_ptr<geom::Geometry> g1
        );

    // Members
    std::vector<const geom::Polygon*> polygons;
    std::vector<const geom::LineString*> lines;
    std::vector<const geom::Point*> points;

    const geom::GeometryFactory* geomFact;
    std::unique_ptr<geom::Geometry> empty;

    UnionStrategy* unionFunction;
    ClassicUnionStrategy defaultUnionFunction;

};


} // namespace geos::operation::union
} // namespace geos::operation
} // namespace geos

#ifdef _MSC_VER
#pragma warning(pop)
#endif

#endif