SimplePolygonTree.h

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// SPDX-FileCopyrightText: Copyright (c) OpenGeoSys Community (opengeosys.org)
// SPDX-License-Identifier: BSD-3-Clause
 
#pragma once
 
#include <list>
 
// GeoLib
#include "Polygon.h"
 
namespace GeoLib
{
class SimplePolygonTree
{
public:
    SimplePolygonTree(Polygon* polygon, SimplePolygonTree* parent);
    virtual ~SimplePolygonTree();
 
    bool isRoot() const;
 
    bool isPolygonInside(const SimplePolygonTree* polygon_hierarchy) const;
    void insertSimplePolygonTree(SimplePolygonTree* polygon_hierarchy);
 
    Polygon const& polygon() const;
    Polygon& polygon();
 
    const SimplePolygonTree* parent() const;

    std::size_t getNumberOfChildren() const { return _children.size(); }
 
private:
    Polygon* _node_polygon;

    std::list<SimplePolygonTree*> _children;
    SimplePolygonTree* _parent;
 
public:
    decltype(_children)::const_iterator begin() const
    {
        return _children.begin();
    }
    decltype(_children)::const_iterator end() const { return _children.end(); }
};

template <typename POLYGONTREETYPE>
void createPolygonTrees(
    std::list<POLYGONTREETYPE*>& list_of_simple_polygon_hierarchies)
{
    for (auto it0 = list_of_simple_polygon_hierarchies.begin();
         it0 != list_of_simple_polygon_hierarchies.end();
         ++it0)
    {
        auto it1 = list_of_simple_polygon_hierarchies.begin();
        while (it1 != list_of_simple_polygon_hierarchies.end())
        {
            if (it0 == it1)
            {  // don't check same polygons
                ++it1;
                // skip test if it1 points to the end after increment
                if (it1 == list_of_simple_polygon_hierarchies.end())
                {
                    break;
                }
            }
            if ((*it0)->isPolygonInside(*it1))
            {
                (*it0)->insertSimplePolygonTree(*it1);
                it1 = list_of_simple_polygon_hierarchies.erase(it1);
            }
            else
            {
                ++it1;
            }
        }
    }
}
 
}  // end namespace GeoLib