/**********************************************************************

 *

 * GEOS - Geometry Engine Open Source

 * http://geos.osgeo.org

 *

 * Copyright (C) 2005-2006 Refractions Research Inc.

 * 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.

 *

 **********************************************************************/

#pragma once

#include <vector>

#include <geos/export.h>

// Forward declarations

namespace geos {

namespace geom {

class CoordinateSequence;

}

}

namespace geos {

namespace geomgraph { // geos::geomgraph

namespace index { // geos::geomgraph::index

/// \brief MonotoneChains are a way of partitioning the segments of an edge to

/// allow for fast searching of intersections.

///

/// Specifically, a sequence of contiguous line segments is a monotone chain

/// iff all the vectors defined by the oriented segments lies in the same

/// quadrant.

///

/// Monotone Chains have the following useful properties:

///

/// - the segments within a monotone chain will never intersect each other

///

/// - the envelope of any contiguous subset of the segments in a monotone chain

///   is simply the envelope of the endpoints of the subset.

///

/// Property 1 means that there is no need to test pairs of segments from

/// within the same monotone chain for intersection. Property 2 allows binary

/// search to be used to find the intersection points of two monotone chains.

/// For many types of real-world data, these properties eliminate a large

/// number of segment comparisons, producing substantial speed gains.

///

/// \note Due to the efficient intersection test, there is no need to limit the

/// size of chains to obtain fast performance.

class GEOS_DLL MonotoneChainIndexer {

public:

    MonotoneChainIndexer() {}

    void getChainStartIndices(const geom::CoordinateSequence*, std::vector<std::size_t>&);

private:

    std::size_t findChainEnd(const geom::CoordinateSequence* pts, std::size_t start);

};

} // namespace geos.geomgraph.index

} // namespace geos.geomgraph

} // namespace geos