#include <boost/thread.hpp>

class Packet
{
	public:
		Packet(int i) : in(i) {}
		int in;
};

typedef boost::promise< Packet > packet_promise;
typedef boost::shared_ptr< packet_promise > packet_promise_shared_ptr;
typedef std::pair< unsigned long, packet_promise_shared_ptr > seq_promise_pair;
typedef std::map< unsigned long, packet_promise_shared_ptr > seq_to_promise_map;

class Demo
{
	private:
		boost::thread setvalue_thread_;
		seq_to_promise_map mymap_;
		boost::mutex mymap_mutex_;
		unsigned long counter_;
		
	public:	
		Demo() :
			counter_(10),
			setvalue_thread_(boost::bind(&Demo::do_calc_in_thread, this))
		{
		}

	  	packet_promise_shared_ptr calc()
	  	{
	  		packet_promise_shared_ptr ptrPromisePacket(new packet_promise());
			boost::mutex::scoped_lock l(mymap_mutex_);
			mymap_.insert(seq_promise_pair(counter_, ptrPromisePacket) );
			counter_++;
			return ptrPromisePacket;
	  	} 

		//calculate in a seperate thread and set_value(), loops forever
		void do_calc_in_thread()
		{
			while(true)
			{
				{
					boost::mutex::scoped_lock l(mymap_mutex_);
					seq_to_promise_map::iterator value_in_map_iter = mymap_.begin();
					for (value_in_map_iter; value_in_map_iter != mymap_.end(); value_in_map_iter++)
					{
						unsigned long in_counter = value_in_map_iter->first;
						//printf("[%d] thread running set value\n", in_counter);
						Packet resultPacket(in_counter);
						value_in_map_iter->second->set_value(resultPacket);			//make a copy
						mymap_.erase(value_in_map_iter);
					}
				}
			}
		}
			
};

int main(int argc, char** argv)
{
	Demo demo;
	unsigned long testCounter=0;

	while(true)
	{
		packet_promise_shared_ptr packetPromisePtr = demo.calc();
		boost::system_time const timeout = boost::get_system_time() + boost::posix_time::milliseconds(500);
		boost::unique_future< Packet > pf = packetPromisePtr->get_future();	//often causes core-dump
		
		if (!pf.timed_wait_until(timeout))			
		{
			printf("[%d] error \n", testCounter);
			break;
		}
		else
		{
			Packet result = pf.get();
			printf("[%d] ok : %d \n", testCounter, result.in);
		}
		testCounter++;
	}
	
}