topic_synchronizer.h

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#ifndef TOPIC_SYNCHRONIZER2_HH
#define TOPIC_SYNCHRONIZER2_HH

#include "ros/ros.h"
#include <boost/thread/mutex.hpp>


class TopicSynchronizer
{
        int expected_count_;
        int count_;
        ros::Time time_;
        boost::function<void ()> callback_;
        boost::mutex mutex_;

public:

        template <typename T>
        TopicSynchronizer(void(T::*fp)(), T* obj) : callback_(boost::bind(fp,obj))
        {
                reset();
        }

        TopicSynchronizer(void (*fp)()) : callback_(fp)
        {
                reset();
        }


        template <typename T, typename M>
        class CallbackFunctor {
                TopicSynchronizer* synchronizer_;
                const boost::function<void (const boost::shared_ptr<M const>&)> callback_;

        public:

                CallbackFunctor(TopicSynchronizer* synchronizer, const boost::function<void (const boost::shared_ptr<M const>&)>& callback) :
                        synchronizer_(synchronizer), callback_(callback)
                {
                }

                void operator()(const boost::shared_ptr<M const>& message)
                {
                        callback_(message);
                        synchronizer_->update(message->header.stamp);
                }
        };

        template <typename T, typename M>
        const boost::function<void (const boost::shared_ptr<M const>&)> synchronize(void(T::*fp)(const boost::shared_ptr<M const>&), T* obj)
        {
          boost::mutex::scoped_lock lock(mutex_);

                expected_count_++;
                return CallbackFunctor<T,M>(this, boost::bind(fp, obj, _1));
        }

        template <typename T, typename M>
        const boost::function<void (const boost::shared_ptr<M const>&)> synchronize(void(T::*fp)(const boost::shared_ptr<M const>&), const boost::shared_ptr<T>& obj)
        {
          boost::mutex::scoped_lock lock(mutex_);

                expected_count_++;
                return CallbackFunctor<T,M>(this, boost::bind(fp, obj.get(), _1));
        }

        template <typename T, typename M>
        const boost::function<void (const boost::shared_ptr<M const>&)> synchronize(void(*fp)(const boost::shared_ptr<M const>&))
        {
          boost::mutex::scoped_lock lock(mutex_);

                expected_count_++;
                return CallbackFunctor<T,M>(this, boost::function<void(const boost::shared_ptr<M>&)>(fp));
        }

        template <typename T, typename M>
        const boost::function<void (const boost::shared_ptr<M const>&)> synchronize(const boost::function<void (const boost::shared_ptr<M const>&)>& callback)
        {
          boost::mutex::scoped_lock lock(mutex_);
                expected_count_++;
                return CallbackFunctor<T,M>(this, callback);
        }

        void reset()
        {
          boost::mutex::scoped_lock lock(mutex_);
                expected_count_ = 0;
        }

        void update(const ros::Time& time)
        {
          boost::mutex::scoped_lock lock(mutex_);
                if (count_==0 || time>time_) {
                        time_ = time;
                        count_ = 0;
                }

                if (time==time_) {
                        count_++;
                }

                if (count_==expected_count_) {
                        callback_();
                }
        }
};

#endif