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 * $Id: extract_indices.h 1370 2011-06-19 01:06:01Z jspricke $
 *
 */

#pragma once

#include <pcl/filters/filter_indices.h>
#include <ctime>
#include <limits>

namespace pcl
{
  /** \brief @b RandomSample applies a random sampling with uniform probability.
    * Based off Algorithm A from the paper "Faster Methods for Random Sampling"
    * by Jeffrey Scott Vitter. The algorithm runs in O(N) and results in sorted
    * indices
    * http://www.ittc.ku.edu/~jsv/Papers/Vit84.sampling.pdf
    * \author Justin Rosen
    * \ingroup filters
    */
  template<typename PointT>
  class RandomSample : public FilterIndices<PointT>
  {
    using FilterIndices<PointT>::filter_name_;
    using FilterIndices<PointT>::getClassName;
    using FilterIndices<PointT>::indices_;
    using FilterIndices<PointT>::input_;
    using FilterIndices<PointT>::negative_;
    using FilterIndices<PointT>::keep_organized_;
    using FilterIndices<PointT>::user_filter_value_;
    using FilterIndices<PointT>::extract_removed_indices_;
    using FilterIndices<PointT>::removed_indices_;

    using PointCloud = typename FilterIndices<PointT>::PointCloud;
    using PointCloudPtr = typename PointCloud::Ptr;
    using PointCloudConstPtr = typename PointCloud::ConstPtr;

    public:

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

      /** \brief Empty constructor. */
      RandomSample (bool extract_removed_indices = false) : 
        FilterIndices<PointT> (extract_removed_indices),
        sample_ (std::numeric_limits<unsigned int>::max()),
        seed_ (static_cast<unsigned int> (time (nullptr)))
      {
        filter_name_ = "RandomSample";
      }

      /** \brief Set number of indices to be sampled.
        * \param sample
        */
      inline void
      setSample (unsigned int sample)
      {
        sample_ = sample;
      }

      /** \brief Get the value of the internal \a sample parameter.
        */
      inline unsigned int
      getSample ()
      {
        return (sample_);
      }

      /** \brief Set seed of random function.
        * \param seed
        */
      inline void
      setSeed (unsigned int seed)
      {
        seed_ = seed;
      }

      /** \brief Get the value of the internal \a seed parameter.
        */
      inline unsigned int
      getSeed ()
      {
        return (seed_);
      }

    protected:

      /** \brief Number of indices that will be returned. */
      unsigned int sample_;
      /** \brief Random number seed. */
      unsigned int seed_;

      /** \brief Sample of point indices
        * \param indices the resultant point cloud indices
        */
      void
      applyFilter (Indices &indices) override;

      /** \brief Return a random number fast using a LCG (Linear Congruential Generator) algorithm.
        * See http://software.intel.com/en-us/articles/fast-random-number-generator-on-the-intel-pentiumr-4-processor/ for more information.
        */
      inline float
      unifRand ()
      {
        return (static_cast<float>(rand () / static_cast<double>(RAND_MAX)));
        //return (((214013 * seed_ + 2531011) >> 16) & 0x7FFF);
      }
  };

  /** \brief @b RandomSample applies a random sampling with uniform probability.
    * \author Justin Rosen
    * \ingroup filters
    */
  template<>
  class PCL_EXPORTS RandomSample<pcl::PCLPointCloud2> : public FilterIndices<pcl::PCLPointCloud2>
  {
    using FilterIndices<pcl::PCLPointCloud2>::filter_name_;
    using FilterIndices<pcl::PCLPointCloud2>::getClassName;

    using PCLPointCloud2 = pcl::PCLPointCloud2;
    using PCLPointCloud2Ptr = PCLPointCloud2::Ptr;
    using PCLPointCloud2ConstPtr = PCLPointCloud2::ConstPtr;

    public:
  
      using Ptr = shared_ptr<RandomSample<pcl::PCLPointCloud2> >;
      using ConstPtr = shared_ptr<const RandomSample<pcl::PCLPointCloud2> >;
  
      /** \brief Empty constructor. */
      RandomSample ():
        sample_ (std::numeric_limits<unsigned int>::max()),
        seed_ (static_cast<unsigned int>(time(nullptr)))
      {
        filter_name_ = "RandomSample";
      }

      /** \brief Set number of indices to be sampled.
        * \param sample
        */
      inline void
      setSample (unsigned int sample)
      {
        sample_ = sample;
      }

      /** \brief Get the value of the internal \a sample parameter.
        */
      inline unsigned int
      getSample ()
      {
        return (sample_);
      }

      /** \brief Set seed of random function.
        * \param seed
        */
      inline void
      setSeed (unsigned int seed)
      {
        seed_ = seed;
      }

      /** \brief Get the value of the internal \a seed parameter.
        */
      inline unsigned int
      getSeed ()
      {
        return (seed_);
      }

    protected:

      /** \brief Number of indices that will be returned. */
      unsigned int sample_;
      /** \brief Random number seed. */
      unsigned int seed_;

      /** \brief Sample of point indices into a separate PointCloud
        * \param output the resultant point cloud
        */
      void
      applyFilter (PCLPointCloud2 &output) override;

      /** \brief Sample of point indices
        * \param indices the resultant point cloud indices
        */
      void
      applyFilter (Indices &indices) override;

      /** \brief Return a random number fast using a LCG (Linear Congruential Generator) algorithm.
        * See http://software.intel.com/en-us/articles/fast-random-number-generator-on-the-intel-pentiumr-4-processor/ for more information.
        */
      inline float
      unifRand ()
      {
        return (static_cast<float> (rand () / static_cast<double>(RAND_MAX)));
      }
   };
}

#ifdef PCL_NO_PRECOMPILE
#include <pcl/filters/impl/random_sample.hpp>
#endif
