time_trigger.cpp

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 *  Point Cloud Library (PCL) - www.pointclouds.org
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#include <pcl/common/time_trigger.h>
#include <pcl/common/time.h>
#include <iostream>

pcl::TimeTrigger::TimeTrigger (double interval, const callback_type& callback)
: callbacks_ ()
, interval_ (interval)
, quit_ (false)
, running_ (false)
, timer_thread_ ()
, condition_ ()
, condition_mutex_ ()
{
  timer_thread_ = boost::thread (boost::bind (&TimeTrigger::thread_function, this));
  registerCallback (callback);
}

pcl::TimeTrigger::TimeTrigger (double interval)
: callbacks_ ()
, interval_ (interval)
, quit_ (false)
, running_ (false)
, timer_thread_ ()
, condition_ ()
, condition_mutex_ ()
{
  timer_thread_ = boost::thread (boost::bind (&TimeTrigger::thread_function, this));
}

pcl::TimeTrigger::~TimeTrigger ()
{
  boost::unique_lock<boost::mutex> lock (condition_mutex_);
  quit_ = true;
  condition_.notify_all ();
  lock.unlock ();
  
  timer_thread_.join ();
}

boost::signals2::connection 
pcl::TimeTrigger::registerCallback (const callback_type& callback)
{
  boost::unique_lock<boost::mutex> lock (condition_mutex_);
  return (callbacks_.connect (callback));
}

void 
pcl::TimeTrigger::setInterval (double interval_seconds)
{
  boost::unique_lock<boost::mutex> lock (condition_mutex_);
  interval_ = interval_seconds;
  // notify, since we could switch from a large interval to a shorter one -> interrupt waiting for timeout!
  condition_.notify_all ();
}

void 
pcl::TimeTrigger::start ()
{
  boost::unique_lock<boost::mutex> lock (condition_mutex_);
  if (!running_)
  {
    running_ = true;
    condition_.notify_all ();
  }
}

void 
pcl::TimeTrigger::stop ()
{
  boost::unique_lock<boost::mutex> lock (condition_mutex_);
  if (running_)
  {
    running_ = false;
    condition_.notify_all ();
  }
}

void 
pcl::TimeTrigger::thread_function ()
{
  static double time = 0;
  while (!quit_)
  {
    time = getTime ();
    boost::unique_lock<boost::mutex> lock (condition_mutex_);
    if (!running_)
      condition_.wait (lock); // wait util start is called or destructor is called
    else
    {
      callbacks_();
      double rest = interval_ + time - getTime ();
      if (rest > 0.0) // without a deadlock is possible, until notify() is called
        condition_.timed_wait (lock, boost::posix_time::microseconds (static_cast<int64_t> ((rest * 1000000))));
    }
  }
}