subscriber.h

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/*
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 * $Id: subscriber.h 43011 2010-08-12 20:30:23Z hsu $
 *
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#ifndef ROSMPI_SUBSCRIBER_H_
#define ROSMPI_SUBSCRIBER_H_

#include "rosmpi/forwards.h"
// ROS
#include <ros/message.h>
#include <ros/message_deserializer.h>
#include <ros/serialized_message.h>
#include <ros/serialization.h>
#include <ros/subscription_callback_helper.h>

namespace rosmpi
{
  class Subscriber
  {
    public:
      Subscriber () {}
      
      ~Subscriber ()
      {
        helper_.reset ();
      }

    public:

      template <typename M> void 
        call ()
      {
        MPI::Status status;
        // Blocking test for a message
        MPI::COMM_WORLD.Probe (MPI_ANY_SOURCE, MPI_ANY_TAG, status);      // for test purposes only

        // Gets the number of "top level" elements
        int count = status.Get_count (MPI_BYTE);

        uint8_t *buf_raw = (uint8_t*)malloc (count * sizeof (uint8_t));
        // Performs a standard-mode blocking receive
        MPI::COMM_WORLD.Recv (buf_raw, count, MPI_BYTE, MPI_ANY_SOURCE, MPI_ANY_TAG);
        count -= 4;

        boost::shared_array<uint8_t> buf (new uint8_t[count]);
        memcpy (buf.get (), &buf_raw[4], count);
        free (buf_raw);

        ros::SerializedMessage m (buf, count);
        
        boost::shared_ptr<ros::M_string> connection_header;     // empty connection header?
        ros::MessageDeserializer deserializer (helper_, m, connection_header);
        ros::VoidConstPtr msg = deserializer.deserialize ();

        ros::SubscriptionCallbackHelperCallParams params;
        // We need to pass an empty function pointer as the last parameter on the constructor
        // of MessageEvent, otherwise boost::make_shared<void> will fail (!!!)
        params.event = ros::MessageEvent<void const> (msg, connection_header, ros::Time::now (), true, ros::MessageEvent<void const>::CreateFunction ());
        helper_->call (params);
      }

    private:
      Subscriber (const ros::SubscriptionCallbackHelperPtr &helper) : helper_ (helper)
      { 
      }

      ros::SubscriptionCallbackHelperPtr helper_;

      friend class NodeHandle;
  };
}

#endif  //#ifndef ROSMPI_SUBSCRIBER_H_