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/* Author: Ioan Sucan */

#ifndef FCL_KNN_NEAREST_NEIGHBORS_H
#define FCL_KNN_NEAREST_NEIGHBORS_H

#include <vector>
#include <boost/bind.hpp>
#include <boost/function.hpp>

namespace fcl
{
/// @brief Abstract representation of a container that can perform nearest neighbors queries
template<typename _T>
class NearestNeighbors
{
public:

  /// @brief The definition of a distance function
  typedef boost::function<double(const _T&, const _T&)> DistanceFunction;

  NearestNeighbors(void)
  {
  }

  virtual ~NearestNeighbors(void)
  {
  }

  /// @brief Set the distance function to use
  virtual void setDistanceFunction(const DistanceFunction &distFun)
  {
    distFun_ = distFun;
  }

  /// @brief Get the distance function used
  const DistanceFunction& getDistanceFunction(void) const
  {
    return distFun_;
  }

  /// @brief Clear the datastructure
  virtual void clear(void) = 0;

  /// @brief Add an element to the datastructure
  virtual void add(const _T &data) = 0;

  /// @brief Add a vector of points
  virtual void add(const std::vector<_T> &data)
  {
    for (typename std::vector<_T>::const_iterator elt = data.begin() ; elt != data.end() ; ++elt)
      add(*elt);
  }

  /// @brief Remove an element from the datastructure
  virtual bool remove(const _T &data) = 0;

  /// @brief Get the nearest neighbor of a point
  virtual _T nearest(const _T &data) const = 0;

  /// @brief Get the k-nearest neighbors of a point
  virtual void nearestK(const _T &data, std::size_t k, std::vector<_T> &nbh) const = 0;

  /// @brief Get the nearest neighbors of a point, within a specified radius
  virtual void nearestR(const _T &data, double radius, std::vector<_T> &nbh) const = 0;

  /// @brief Get the number of elements in the datastructure
  virtual std::size_t size(void) const = 0;

  /// @brief Get all the elements in the datastructure
  virtual void list(std::vector<_T> &data) const = 0;

protected:

  /// @brief The used distance function
  DistanceFunction distFun_;

};
}


#endif
