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#pragma once

#include <pcl/memory.h>
#include <pcl/pcl_macros.h>
#include <pcl/point_cloud.h>

namespace pcl
{
  /** \brief Comparator is the base class for comparators that compare two points given some function.
    * Currently intended for use with OrganizedConnectedComponentSegmentation
    *
    * \author Alex Trevor
    */
  template <typename PointT>
  class Comparator
  {
    public:
      using PointCloud = pcl::PointCloud<PointT>;
      using PointCloudPtr = typename PointCloud::Ptr;
      using PointCloudConstPtr = typename PointCloud::ConstPtr;

      using Ptr = shared_ptr<Comparator<PointT> >;
      using ConstPtr = shared_ptr<const Comparator<PointT> >;

      /** \brief Empty constructor for comparator. */
      Comparator () : input_ ()
      {
      }
      
      /** \brief Empty destructor for comparator. */
      virtual
      ~Comparator () = default;
      
      /** \brief Set the input cloud for the comparator.
        * \param[in] cloud the point cloud this comparator will operate on
        */
      virtual void 
      setInputCloud (const PointCloudConstPtr& cloud)
      {
        input_ = cloud;
      }
      
      /** \brief Get the input cloud this comparator operates on. */
      virtual PointCloudConstPtr
      getInputCloud () const
      {
        return (input_);
      }

      /** \brief Compares the two points in the input cloud designated by these two indices.
        * This is pure virtual and must be implemented by subclasses with some comparison function.
        * \param[in] idx1 the index of the first point.
        * \param[in] idx2 the index of the second point.
        */
      virtual bool
      compare (int idx1, int idx2) const = 0;
      
    protected:
      PointCloudConstPtr input_;
    public:
      PCL_MAKE_ALIGNED_OPERATOR_NEW
  };
}