LinkedRing.h

/**********************************************************************
 *
 * GEOS - Geometry Engine Open Source
 * http://geos.osgeo.org
 *
 * Copyright (C) 2021 Paul Ramsey <pramsey@cleverelephant.ca>
 *
 * 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 <memory>
 
#include <geos/geom/Coordinate.h>
#include <geos/geom/CoordinateSequence.h>
#include <geos/constants.h>
 
namespace geos {
namespace simplify { // geos::simplify
 
 
 
class LinkedRing
{
    using Coordinate = geos::geom::Coordinate;
    using CoordinateSequence = geos::geom::CoordinateSequence;
 
    private:
 
        const CoordinateSequence& m_coord;
        std::size_t m_size;
        std::vector<std::size_t> m_next;
        std::vector<std::size_t> m_prev;
 
        static std::vector<std::size_t> createNextLinks(std::size_t size);
        static std::vector<std::size_t> createPrevLinks(std::size_t size);
 
 
    public:
 
        LinkedRing(const CoordinateSequence& cs)
            : m_coord(cs)
            , m_size(cs.size()-1)
            , m_next(createNextLinks(m_size))
            , m_prev(createPrevLinks(m_size))
            {};
 
        std::size_t size() const;
        std::size_t next(std::size_t i) const;
        std::size_t prev(std::size_t i) const;
        const Coordinate& getCoordinate(std::size_t index) const;
        const Coordinate& prevCoordinate(std::size_t index) const;
        const Coordinate& nextCoordinate(std::size_t index) const;
        bool hasCoordinate(std::size_t index) const;
        void remove(std::size_t index);
        std::unique_ptr<CoordinateSequence> getCoordinates() const;
 
 
}; // LinkedRing
 
 
} // geos::simplify
} // geos