conversions.h

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 * $Id: conversions.h 3746 2011-12-31 22:19:47Z rusu $
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#ifndef PCL_ROS_CONVERSIONS_H_ 
#define PCL_ROS_CONVERSIONS_H_

#include <sensor_msgs/PointField.h>
#include <sensor_msgs/PointCloud2.h>
#include <sensor_msgs/Image.h>
#include <pcl/point_cloud.h>
#include <pcl/point_traits.h>
#include <pcl/for_each_type.h>
#include <pcl/exceptions.h>
#include <pcl/console/print.h>
#include <boost/foreach.hpp>

namespace pcl
{
  namespace detail
  {
    // For converting template point cloud to message.
    template<typename PointT>
    struct FieldAdder
    {
      FieldAdder (std::vector<sensor_msgs::PointField>& fields) : fields_ (fields) {};
      
      template<typename U> void operator() ()
      {
        sensor_msgs::PointField f;
        f.name = traits::name<PointT, U>::value;
        f.offset = traits::offset<PointT, U>::value;
        f.datatype = traits::datatype<PointT, U>::value;
        f.count = traits::datatype<PointT, U>::size;
        fields_.push_back (f);
      }

      std::vector<sensor_msgs::PointField>& fields_;
    };

    // For converting message to template point cloud.
    template<typename PointT>
    struct FieldMapper
    {
      FieldMapper (const std::vector<sensor_msgs::PointField>& fields,
                   std::vector<FieldMapping>& map)
        : fields_ (fields), map_ (map)
      {
      }
      
      template<typename Tag> void operator() ()
      {
        const char* name = traits::name<PointT, Tag>::value;
        BOOST_FOREACH(const sensor_msgs::PointField& field, fields_)
        {
          if (field.name == name)
          {
            typedef traits::datatype<PointT, Tag> Data;
            assert (Data::value == field.datatype);
            //@todo: Talk to Patrick about this
            //assert (Data::size  == field.count);
            
            FieldMapping mapping;
            mapping.serialized_offset = field.offset;
            mapping.struct_offset = traits::offset<PointT, Tag>::value;
            mapping.size = sizeof (typename Data::type);
            map_.push_back (mapping);
            return;
          }
        }
        // didn't find it...
        std::stringstream ss;
        ss << "Failed to find a field named: '" << name
           << "'. Cannot convert message to PCL type.";
        PCL_ERROR ("%s\n", ss.str().c_str());
        throw pcl::InvalidConversionException(ss.str());
      }

      const std::vector<sensor_msgs::PointField>& fields_;
      std::vector<FieldMapping>& map_;
    };

    inline bool fieldOrdering(const FieldMapping& a, const FieldMapping& b)
    {
      return a.serialized_offset < b.serialized_offset;
    }

  } //namespace detail

  template<typename PointT>
  void createMapping (const std::vector<sensor_msgs::PointField>& msg_fields, MsgFieldMap& field_map)
  {
    // Create initial 1-1 mapping between serialized data segments and struct fields
    detail::FieldMapper<PointT> mapper (msg_fields, field_map);
    for_each_type< typename traits::fieldList<PointT>::type > (mapper);

    // Coalesce adjacent fields into single memcpy's where possible
    if (field_map.size() > 1)
    {
      std::sort(field_map.begin(), field_map.end(), detail::fieldOrdering);
      MsgFieldMap::iterator i = field_map.begin(), j = i + 1;
      while (j != field_map.end())
      {
        // This check is designed to permit padding between adjacent fields.
        if (j->serialized_offset - i->serialized_offset == j->struct_offset - i->struct_offset)
        {
          i->size += (j->struct_offset + j->size) - (i->struct_offset + i->size);
          j = field_map.erase(j);
        }
        else
        {
          ++i;
          ++j;
        }
      }
    }
  }

  template<typename PointT>  
  void fromROSMsg (const sensor_msgs::PointCloud2& msg, pcl::PointCloud<PointT>& cloud,
                   const MsgFieldMap& field_map)
  {
    // Copy info fields
    cloud.header   = msg.header;
    cloud.width    = msg.width;
    cloud.height   = msg.height;
    cloud.is_dense = msg.is_dense == 1;

    // Copy point data
    uint32_t num_points = msg.width * msg.height;
    cloud.points.resize (num_points);
    uint8_t* cloud_data = reinterpret_cast<uint8_t*>(&cloud.points[0]);

    // Check if we can copy adjacent points in a single memcpy
    if (field_map.size() == 1 &&
        field_map[0].serialized_offset == 0 &&
        field_map[0].struct_offset == 0 &&
        msg.point_step == sizeof(PointT))
    {
      uint32_t cloud_row_step = sizeof(PointT) * cloud.width;
      const uint8_t* msg_data = &msg.data[0];
      // Should usually be able to copy all rows at once
      if (msg.row_step == cloud_row_step)
      {
        memcpy (cloud_data, msg_data, msg.data.size());
      }
      else
      {
        for (uint32_t i = 0; i < msg.height;
             ++i, cloud_data += cloud_row_step, msg_data += msg.row_step)
          memcpy (cloud_data, msg_data, cloud_row_step);
      }
    }
    else
    {
      // If not, memcpy each group of contiguous fields separately
      for (uint32_t row = 0; row < msg.height; ++row)
      {
        const uint8_t* row_data = &msg.data[row * msg.row_step];
        for (uint32_t col = 0; col < msg.width; ++col)
        {
          const uint8_t* msg_data = row_data + col * msg.point_step;
          BOOST_FOREACH (const detail::FieldMapping& mapping, field_map)
          {
            memcpy (cloud_data + mapping.struct_offset, msg_data + mapping.serialized_offset, mapping.size);
          }
          cloud_data += sizeof (PointT);
        }
      }
    }
  }

  template<typename PointT>  
  void fromROSMsg (const sensor_msgs::PointCloud2& msg, pcl::PointCloud<PointT>& cloud)
  {
    MsgFieldMap field_map;
    createMapping<PointT> (msg.fields, field_map);
    fromROSMsg (msg, cloud, field_map);
  }

  template<typename PointT>
  void toROSMsg (const pcl::PointCloud<PointT>& cloud, sensor_msgs::PointCloud2& msg)
  {
    // Ease the user's burden on specifying width/height for unorganized datasets
    if (cloud.width == 0 && cloud.height == 0)
    {
      msg.width  = (uint32_t) cloud.points.size ();
      msg.height = 1;
    }
    else
    {
      assert (cloud.points.size () == cloud.width * cloud.height);
      msg.height = cloud.height;
      msg.width  = cloud.width;
    }

    // Fill point cloud binary data (padding and all)
    size_t data_size = sizeof (PointT) * cloud.points.size ();
    msg.data.resize (data_size);
    memcpy (&msg.data[0], &cloud.points[0], data_size);

    // Fill fields metadata
    msg.fields.clear ();
    for_each_type< typename traits::fieldList<PointT>::type > (detail::FieldAdder<PointT>(msg.fields));

    msg.header     = cloud.header;
    msg.point_step = sizeof (PointT);
    msg.row_step   = sizeof (PointT) * msg.width;
    msg.is_dense   = cloud.is_dense;
  }

  template<typename CloudT> void
  toROSMsg(const CloudT& cloud, sensor_msgs::Image& msg)
  {
    // Ease the user's burden on specifying width/height for unorganized datasets
    if (cloud.width == 0 && cloud.height == 0)
      throw std::runtime_error("Needs to be a dense like cloud!!");
    else
    {
      if(cloud.points.size () != cloud.width * cloud.height){
        throw std::runtime_error("The width and height do not match the cloud size!");
      }
      msg.height = cloud.height;
      msg.width = cloud.width;
    }

    // ensor_msgs::image_encodings::BGR8;
    msg.encoding = "bgr8";
    msg.step = msg.width * sizeof(uint8_t) * 3;
    msg.data.resize(msg.step * msg.height);
    for (size_t y = 0; y < cloud.height; y++)
    {
      for (size_t x = 0; x < cloud.width; x++)
      {
        uint8_t * pixel = &(msg.data[y * msg.step + x * 3]);
        memcpy(pixel, &cloud (x, y).rgb, 3 * sizeof(uint8_t));
      }
    }
  }

  inline void
  toROSMsg (const sensor_msgs::PointCloud2& cloud, sensor_msgs::Image& msg)
  {
    int rgb_index = -1;
    // Get the index we need
    for (size_t d = 0; d < cloud.fields.size (); ++d)
      if (cloud.fields[d].name == "rgb")
      {
        rgb_index = (int) d;
        break;
      }

    if(rgb_index == -1)
      throw std::runtime_error ("No rgb field!!");
    if (cloud.width == 0 && cloud.height == 0)
      throw std::runtime_error ("Needs to be a dense like cloud!!");
    else
    {
      msg.height = cloud.height;
      msg.width = cloud.width;
    }
    int rgb_offset = cloud.fields[rgb_index].offset;
    int point_step = cloud.point_step;

    // sensor_msgs::image_encodings::BGR8;
    msg.encoding = "bgr8";
    msg.step = msg.width * sizeof(uint8_t) * 3;
    msg.data.resize (msg.step * msg.height);

    for (size_t y = 0; y < cloud.height; y++)
    {
      for (size_t x = 0; x < cloud.width; x++, rgb_offset += point_step)
      {
        uint8_t * pixel = &(msg.data[y * msg.step + x * 3]);
        memcpy (pixel, &(cloud.data[rgb_offset]), 3 * sizeof (uint8_t));
      }
    }
  }
}

#endif  //#ifndef PCL_ROS_CONVERSIONS_H_