GridN.h

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/* Author: Ioan Sucan */

#ifndef OMPL_DATASTRUCTURES_GRID_N_
#define OMPL_DATASTRUCTURES_GRID_N_

#include "ompl/datastructures/Grid.h"

namespace ompl
{
    template <typename _T>
    class GridN : public Grid<_T>
    {
    public:
        using BaseCell = typename Grid<_T>::Cell;

        using BaseCellArray = typename Grid<_T>::CellArray;

        using Coord = typename Grid<_T>::Coord;

        struct Cell : public BaseCell
        {
            unsigned int neighbors{0};

            bool border{true};

            Cell() = default;

            ~Cell() override = default;
        };

        using CellArray = std::vector<Cell *>;

        explicit GridN(unsigned int dimension) : Grid<_T>(dimension)
        {
            hasBounds_ = false;
            overrideCellNeighborsLimit_ = false;
            setDimension(dimension);
        }

        ~GridN() override = default;

        void setDimension(unsigned int dimension)
        {
            assert(Grid<_T>::empty() == true);
            Grid<_T>::dimension_ = dimension;
            Grid<_T>::maxNeighbors_ = 2 * dimension;
            if (!overrideCellNeighborsLimit_)
                interiorCellNeighborsLimit_ = Grid<_T>::maxNeighbors_;
        }

        void setBounds(const Coord &low, const Coord &up)
        {
            lowBound_ = low;
            upBound_ = up;
            hasBounds_ = true;
        }

        void setInteriorCellNeighborLimit(unsigned int count)
        {
            interiorCellNeighborsLimit_ = count;
            assert(interiorCellNeighborsLimit_ > 0);
            overrideCellNeighborsLimit_ = true;
        }

        Cell *getCell(const Coord &coord) const
        {
            return static_cast<Cell *>(Grid<_T>::getCell(coord));
        }

        void neighbors(const Cell *cell, CellArray &list) const
        {
            Coord test = cell->coord;
            neighbors(test, list);
        }

        void neighbors(const Coord &coord, CellArray &list) const
        {
            Coord test = coord;
            neighbors(test, list);
        }

        void neighbors(Coord &coord, CellArray &list) const
        {
            BaseCellArray baselist;
            Grid<_T>::neighbors(coord, baselist);
            list.reserve(list.size() + baselist.size());
            for (const auto &c : baselist)
                list.push_back(static_cast<Cell *>(c));
        }

        BaseCell *createCell(const Coord &coord, BaseCellArray *nbh = nullptr) override
        {
            auto *cell = new Cell();
            cell->coord = coord;

            BaseCellArray *list = nbh ? nbh : new BaseCellArray();
            Grid<_T>::neighbors(cell->coord, *list);

            for (auto cl = list->begin(); cl != list->end(); ++cl)
            {
                auto *c = static_cast<Cell *>(*cl);
                c->neighbors++;
                if (c->border && c->neighbors >= interiorCellNeighborsLimit_)
                    c->border = false;
            }

            cell->neighbors = numberOfBoundaryDimensions(cell->coord) + list->size();
            if (cell->border && cell->neighbors >= interiorCellNeighborsLimit_)
                cell->border = false;

            if (!nbh)
                delete list;

            return cell;
        }

        bool remove(BaseCell *cell) override
        {
            if (cell)
            {
                auto *list = new BaseCellArray();
                Grid<_T>::neighbors(cell->coord, *list);
                for (auto cl = list->begin(); cl != list->end(); ++cl)
                {
                    auto *c = static_cast<Cell *>(*cl);
                    c->neighbors--;
                    if (!c->border && c->neighbors < interiorCellNeighborsLimit_)
                        c->border = true;
                }
                delete list;
                auto pos = Grid<_T>::hash_.find(&cell->coord);
                if (pos != Grid<_T>::hash_.end())
                {
                    Grid<_T>::hash_.erase(pos);
                    return true;
                }
            }
            return false;
        }

        void getCells(CellArray &cells) const
        {
            for (const auto &h : Grid<_T>::hash_)
                cells.push_back(static_cast<Cell *>(h.second));
        }

    protected:
        unsigned int numberOfBoundaryDimensions(const Coord &coord) const
        {
            unsigned int result = 0;
            if (hasBounds_)
            {
                for (unsigned int i = 0; i < Grid<_T>::dimension_; ++i)
                    if (coord[i] == lowBound_[i] || coord[i] == upBound_[i])
                        result++;
            }
            return result;
        }

        bool hasBounds_;

        Coord lowBound_;

        Coord upBound_;

        unsigned int interiorCellNeighborsLimit_;

        bool overrideCellNeighborsLimit_;
    };
}

#endif