/*
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 *  Point Cloud Library (PCL) - www.pointclouds.org
 *  Copyright (c) 2010-2011, Willow Garage, Inc.
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 *     with the distribution.
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 * $Id: distances.cpp 527 2011-04-17 23:57:26Z rusu $
 *
 */

#include <limits>

#include <pcl/PCLPointCloud2.h> // for PCLPointCloud2
#include <pcl/common/common.h>
#include <pcl/console/print.h>

//////////////////////////////////////////////////////////////////////////////////////////////
void 
pcl::getMinMax (const pcl::PCLPointCloud2 &cloud, int,
                const std::string &field_name, float &min_p, float &max_p)
{
  min_p = std::numeric_limits<float>::max();
  max_p = -std::numeric_limits<float>::max();

  const auto result = std::find_if(cloud.fields.begin (), cloud.fields.end (),
      [&field_name](const auto& field) { return field.name == field_name; });
  if (result == cloud.fields.end ())
  {
    PCL_ERROR ("[getMinMax] Invalid field (%s) given!\n", field_name.c_str ());
    return;
  }
  const auto field_idx = std::distance(cloud.fields.begin (), result);

  for (uindex_t i = 0; i < cloud.fields[field_idx].count; ++i)
  {
    float data;
    // TODO: replace float with the real data type
    memcpy (&data, &cloud.data[cloud.fields[field_idx].offset + i * sizeof (float)], sizeof (float));
    min_p = (data > min_p) ? min_p : data; 
    max_p = (data < max_p) ? max_p : data; 
  }
}

//////////////////////////////////////////////////////////////////////////////////////////////
void
pcl::getMeanStdDev (const std::vector<float> &values, double &mean, double &stddev)
{
  double sum = 0, sq_sum = 0;

  for (const float &value : values)
  {
    sum += value;
    sq_sum += value * value;
  }
  mean = sum / static_cast<double>(values.size ());
  double variance = (sq_sum - sum * sum / static_cast<double>(values.size ())) / (static_cast<double>(values.size ()) - 1);
  stddev = sqrt (variance);
}

