GridB.h

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/* Author: Ioan Sucan */
 
#ifndef OMPL_DATASTRUCTURES_GRID_B_
#define OMPL_DATASTRUCTURES_GRID_B_
 
#include "ompl/datastructures/GridN.h"
#include "ompl/datastructures/BinaryHeap.h"
#include "ompl/util/DisableCompilerWarning.h"
 
OMPL_PUSH_DISABLE_CLANG_WARNING(-Woverloaded - virtual)
 
namespace ompl
{
    template <typename _T, class LessThanExternal = std::less<_T>, class LessThanInternal = LessThanExternal>
    class GridB : public GridN<_T>
    {
    public:
        using Cell = typename GridN<_T>::Cell;
        using BaseCell = typename GridN<_T>::BaseCell;

        using CellArray = typename GridN<_T>::CellArray;

        using Coord = typename GridN<_T>::Coord;
 
    protected:
        // the type of cell here needs an extra pointer to allow the updatable heap to work fast
        // however, this stays hidden from the user
        struct CellX : public Cell
        {
            CellX() : Cell()
            {
            }
 
            ~CellX() override = default;
 
            void *heapElement;
 
            EIGEN_MAKE_ALIGNED_OPERATOR_NEW
        };

 
    public:
        using EventCellUpdate = void (*)(Cell *, void *);

        explicit GridB(unsigned int dimension) : GridN<_T>(dimension)
        {
            setupHeaps();
        }
 
        ~GridB() override
        {
            clearHeaps();
        }

        void onCellUpdate(EventCellUpdate event, void *arg)
        {
            eventCellUpdate_ = event;
            eventCellUpdateData_ = arg;
        }

        Cell *topInternal() const
        {
            auto *top = static_cast<Cell *>(internal_.top()->data);
            return top ? top : topExternal();
        }

        Cell *topExternal() const
        {
            auto *top = static_cast<Cell *>(external_.top()->data);
            return top ? top : topInternal();
        }

        unsigned int countInternal() const
        {
            return internal_.size();
        }

        unsigned int countExternal() const
        {
            return external_.size();
        }

        double fracExternal() const
        {
            return external_.empty() ? 0.0 : (double)(external_.size()) / (double)(external_.size() + internal_.size());
        }

        double fracInternal() const
        {
            return 1.0 - fracExternal();
        }

        void update(Cell *cell)
        {
            eventCellUpdate_(cell, eventCellUpdateData_);
            if (cell->border)
                external_.update(
                    reinterpret_cast<typename externalBHeap::Element *>(static_cast<CellX *>(cell)->heapElement));
            else
                internal_.update(
                    reinterpret_cast<typename internalBHeap::Element *>(static_cast<CellX *>(cell)->heapElement));
        }

        void updateAll()
        {
            std::vector<Cell *> cells;
            this->getCells(cells);
            for (int i = cells.size() - 1; i >= 0; --i)
                eventCellUpdate_(cells[i], eventCellUpdateData_);
            external_.rebuild();
            internal_.rebuild();
        }

        virtual Cell *createCell(const Coord &coord, CellArray *nbh = nullptr)
        {
            auto *cell = new CellX();
            cell->coord = coord;
 
            CellArray *list = nbh ? nbh : new CellArray();
            this->neighbors(cell->coord, *list);
 
            for (auto cl = list->begin(); cl != list->end(); ++cl)
            {
                auto *c = static_cast<CellX *>(*cl);
                bool wasBorder = c->border;
                c->neighbors++;
                if (c->border && c->neighbors >= GridN<_T>::interiorCellNeighborsLimit_)
                    c->border = false;
 
                eventCellUpdate_(c, eventCellUpdateData_);
 
                if (c->border)
                    external_.update(reinterpret_cast<typename externalBHeap::Element *>(c->heapElement));
                else
                {
                    if (wasBorder)
                    {
                        external_.remove(reinterpret_cast<typename externalBHeap::Element *>(c->heapElement));
                        internal_.insert(c);
                    }
                    else
                        internal_.update(reinterpret_cast<typename internalBHeap::Element *>(c->heapElement));
                }
            }
 
            cell->neighbors = GridN<_T>::numberOfBoundaryDimensions(cell->coord) + list->size();
            if (cell->border && cell->neighbors >= GridN<_T>::interiorCellNeighborsLimit_)
                cell->border = false;
 
            if (!nbh)
                delete list;
 
            return static_cast<Cell *>(cell);
        }

        virtual void add(Cell *cell)
        {
            auto *ccell = static_cast<CellX *>(cell);
            eventCellUpdate_(ccell, eventCellUpdateData_);
 
            GridN<_T>::add(cell);
 
            if (cell->border)
                external_.insert(ccell);
            else
                internal_.insert(ccell);
        }

        bool remove(BaseCell *cell) override
        {
            if (cell)
            {
                auto *list = new CellArray();
                this->neighbors(cell->coord, *list);
 
                for (auto cl = list->begin(); cl != list->end(); ++cl)
                {
                    auto *c = static_cast<CellX *>(*cl);
                    bool wasBorder = c->border;
                    c->neighbors--;
                    if (!c->border && c->neighbors < GridN<_T>::interiorCellNeighborsLimit_)
                        c->border = true;
 
                    eventCellUpdate_(c, eventCellUpdateData_);
 
                    if (c->border)
                    {
                        if (wasBorder)
                            external_.update(reinterpret_cast<typename externalBHeap::Element *>(c->heapElement));
                        else
                        {
                            internal_.remove(reinterpret_cast<typename internalBHeap::Element *>(c->heapElement));
                            external_.insert(c);
                        }
                    }
                    else
                        internal_.update(reinterpret_cast<typename internalBHeap::Element *>(c->heapElement));
                }
 
                delete list;
 
                auto pos = GridN<_T>::hash_.find(&cell->coord);
                if (pos != GridN<_T>::hash_.end())
                {
                    GridN<_T>::hash_.erase(pos);
                    auto *cx = static_cast<CellX *>(cell);
                    if (cx->border)
                        external_.remove(reinterpret_cast<typename externalBHeap::Element *>(cx->heapElement));
                    else
                        internal_.remove(reinterpret_cast<typename internalBHeap::Element *>(cx->heapElement));
                    return true;
                }
            }
            return false;
        }
 
        void clear() override
        {
            GridN<_T>::clear();
            clearHeaps();
        }
 
        void status(std::ostream &out = std::cout) const override
        {
            GridN<_T>::status(out);
            out << countInternal() << " internal cells" << std::endl;
            out << countExternal() << " external cells" << std::endl;
        }
 
    protected:
        EventCellUpdate eventCellUpdate_;

        void *eventCellUpdateData_;

        static void noCellUpdate(Cell * /*unused*/, void * /*unused*/)
        {
        }

        void setupHeaps()
        {
            eventCellUpdate_ = &noCellUpdate;
            eventCellUpdateData_ = nullptr;
            internal_.onAfterInsert(&setHeapElementI, nullptr);
            external_.onAfterInsert(&setHeapElementE, nullptr);
        }

        void clearHeaps()
        {
            internal_.clear();
            external_.clear();
        }

        struct LessThanInternalCell
        {
            bool operator()(const CellX *const a, const CellX *const b) const
            {
                return lt_(a->data, b->data);
            }
 
        private:
            LessThanInternal lt_;
        };

        struct LessThanExternalCell
        {
            bool operator()(const CellX *const a, const CellX *const b) const
            {
                return lt_(a->data, b->data);
            }
 
        private:
            LessThanExternal lt_;
        };

        using internalBHeap = BinaryHeap<CellX *, LessThanInternalCell>;

        using externalBHeap = BinaryHeap<CellX *, LessThanExternalCell>;

        static void setHeapElementI(typename internalBHeap::Element *element, void * /*unused*/)
        {
            element->data->heapElement = reinterpret_cast<void *>(element);
        }

        static void setHeapElementE(typename externalBHeap::Element *element, void * /*unused*/)
        {
            element->data->heapElement = reinterpret_cast<void *>(element);
        }

        internalBHeap internal_;

        externalBHeap external_;
    };
}  // namespace ompl
 
OMPL_POP_CLANG
 
#endif