hz.cpp

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// ROS and messages
#include <ros/ros.h>

// LCM and messages
#include <lcm/lcm-cpp.hpp>
#include <dataspeed_pds_lcm/status_t.hpp>
using namespace dataspeed_pds_lcm;

// LCM handle
lcm::LCM * g_lcm = NULL;

void timerCallback(const ros::TimerEvent&, int id)
{
  ROS_ASSERT((0 <= id) && (id <= 3));
  status_t msg;
  memset(&msg, 0x00, sizeof(msg));
  msg.unit_id = id;
  g_lcm->publish("STATUS", &msg);
}

int main(int argc, char **argv)
{
  ros::init(argc, argv, "sim");
  ros::NodeHandle nh;
  ros::NodeHandle nh_priv("~");

  // Configurable period
  double hz = 50; // 50 Hz
  nh_priv.getParam("hz", hz);

  // Multiple units (optional)
  int unit_id = 0;
  nh_priv.getParam("unit_id", unit_id);
  if (unit_id < 0) {
    unit_id = 0;
  } else if (unit_id > 3) {
    unit_id = 3;
  }

  // LCM URL
  std::string lcm_url;
  nh_priv.getParam("lcm_url", lcm_url);
  if (lcm_url.empty()) {
    lcm_url = "udpm://225.0.0.0:7667?ttl=0";
  }

  // Initialize LCM
  lcm::LCM * lcm;
  while(ros::ok()) {
    lcm = new lcm::LCM(lcm_url);
    if(lcm->good()) {
      break;
    } else {
      ROS_WARN_THROTTLE(10.0,"lcm is not initialized, is the network ready?");
      delete lcm;
    }
    ros::Duration(1.0).sleep();
  }
  ROS_INFO("LCM connected to %s", lcm_url.c_str());

  // Hold onto the LCM handle
  g_lcm = lcm;

  // Setup Timers
  std::vector<ros::Timer> timers;
  for (int i = 0; i <= unit_id; i++) {
    timers.push_back(nh.createTimer(ros::Duration(1.0 / hz), boost::bind(&timerCallback, _1, i)));
  }

  // Handle callbacks until shutdown
  ros::spin();

  return 0;
}