kev/Drawer/GVision/MLMicroStructure/mlgeos/geos/index/chain/MonotoneChainBuilder.h

/**********************************************************************
 *
 * GEOS - Geometry Engine Open Source
 * http://geos.osgeo.org
 *
 * Copyright (C) 2001-2002 Vivid Solutions 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: index/chain/MonotoneChainBuilder.java r388 (JTS-1.12)
 *
 **********************************************************************/

#ifndef GEOS_IDX_CHAIN_MONOTONECHAINBUILDER_H
#define GEOS_IDX_CHAIN_MONOTONECHAINBUILDER_H

#include <geos/export.h>
#include <memory>
#include <vector>
#include <cstddef>

// Forward declarations
namespace geos {
namespace geom {
class CoordinateSequence;
}
namespace index {
namespace chain {
class MonotoneChain;
}
}
}

namespace geos {
namespace index { // geos::index
namespace chain { // geos::index::chain

/** \brief
 * Constructs [MonotoneChains](@ref index::chain::MonotoneChain)
 * for sequences of [Coordinates](@ref geom::Coordinate).
 *
 * TODO: use vector<const Coordinate*> instead ?
 */
class GEOS_DLL MonotoneChainBuilder {

public:

    MonotoneChainBuilder() {}

    /** \brief
     * Return a newly-allocated vector of newly-allocated
     * MonotoneChain objects for the given CoordinateSequence.
     */
    static std::unique_ptr<std::vector<std::unique_ptr<MonotoneChain>>> getChains(
        const geom::CoordinateSequence* pts,
        void* context);

    /** \brief
     * Computes a list of the {@link MonotoneChain}s for a list of coordinates,
     * attaching a context data object to each.
     *
     * @param pts the list of points to compute chains for
     * @param context a data object to attach to each chain
     * @param[out] mcList a list of the monotone chains for the points
     */
    static void getChains(const geom::CoordinateSequence* pts,
                          void* context,
                          std::vector<std::unique_ptr<MonotoneChain>>& mcList);

    static std::unique_ptr<std::vector<std::unique_ptr<MonotoneChain>>>
    getChains(const geom::CoordinateSequence* pts)
    {
        return getChains(pts, nullptr);
    }

    /**
     * Disable copy construction and assignment. Apparently needed to make this
     * class compile under MSVC. (See https://stackoverflow.com/q/29565299)
     */
    MonotoneChainBuilder(const MonotoneChainBuilder&) = delete;
    MonotoneChainBuilder& operator=(const MonotoneChainBuilder&) = delete;


private:

    /** \brief
     * Finds the index of the last point in a monotone chain
     * starting at a given point.
     *
     * Repeated points (0-length segments) are included
     * in the monotone chain returned.
     *
     * @param pts the points to scan
     * @param start the index of the start of this chain
     * @return the index of the last point in the monotone chain
     *         starting at <code>start</code>.
     *
     * @note aborts if 'start' is >= pts.getSize()
     */
    static std::size_t findChainEnd(const geom::CoordinateSequence& pts,
                                    std::size_t start);
};

} // namespace geos::index::chain
} // namespace geos::index
} // namespace geos

#endif // GEOS_IDX_CHAIN_MONOTONECHAINBUILDER_H