CascadedPolygonUnion.h

/**********************************************************************
 * $Id: CascadedPolygonUnion.h 2571 2009-06-08 21:53:35Z strk $
 *
 * GEOS - Geometry Engine Open Source
 * http://geos.refractions.net
 *
 * 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 rev 1.10 (JTS-1.10)
 *
 **********************************************************************/

#ifndef GEOS_OP_UNION_CASCADEDPOLYGONUNION_H
#define GEOS_OP_UNION_CASCADEDPOLYGONUNION_H

#include <vector>
#include <algorithm>

// 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 GeometryListHolder : public std::vector<geom::Geometry*>
{
private:
    typedef std::vector<geom::Geometry*> base_type;

public:
    GeometryListHolder() {}
    ~GeometryListHolder()
    {
        std::for_each(ownedItems.begin(), ownedItems.end(), 
            &GeometryListHolder::deleteItem);
    }

    // items need to be deleted in the end
    void push_back_owned(geom::Geometry* item)
    {
        this->base_type::push_back(item);
        ownedItems.push_back(item);
    }

    geom::Geometry* getGeometry(std::size_t index)
    {
      if (index >= this->base_type::size()) 
          return NULL;
      return (*this)[index];
    }

private:
    static void deleteItem(geom::Geometry* item);

private:
    std::vector<geom::Geometry*> ownedItems;
};

class CascadedPolygonUnion 
{
private:
    std::vector<geom::Polygon*>* inputPolys;
    geom::GeometryFactory const* geomFactory;

    static int const STRTREE_NODE_CAPACITY = 4;

public:
    CascadedPolygonUnion();

    static geom::Geometry* Union(std::vector<geom::Polygon*>* polys);

    static geom::Geometry* Union(const geom::MultiPolygon* polys);

    CascadedPolygonUnion(std::vector<geom::Polygon*>* polys)
      : inputPolys(polys),
        geomFactory(NULL)
    {}

    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);

    geom::Geometry* unionOptimized(geom::Geometry* g0, geom::Geometry* g1);

    geom::Geometry* unionUsingEnvelopeIntersection(geom::Geometry* g0, 
        geom::Geometry* g1, geom::Envelope const& common);

    geom::Geometry* extractByEnvelope(geom::Envelope const& env, 
        geom::Geometry* geom, std::vector<geom::Geometry*>& disjointGeoms);

    static geom::Geometry* unionActual(geom::Geometry* g0, geom::Geometry* g1);
};

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

#endif

/**********************************************************************
 * $Log$
 *
 **********************************************************************/

---