Re: STL container advice

Mark P <>
Wed, 14 Mar 2007 00:10:49 GMT
brekehan wrote:

I am implementing a event messaging system. Basically I do:

---update cycle---

processing/check for new events
   allocate a new event
   put it in a std::queue

Dispatch events
   make an event equal to std::queue.front()
   pop an event from the std::queue
   get its type
   send it off to registered handlers

Now problem is that the handler may or may not process it. The handler
will return me a 0 if it was taken care of and a 1 if not. If the
event was not handled I want to leave it to be dispatched again next
update cycle. A std::queue only has a front() function, but no
iterator. So I cannot get the event, decide if I still want it or not,
then go to the next event without getting rid of the first. I cannot
iterate through and choose to erase handled events.

First I considered making another queue and putting unhandled events
into it then copying that queue to the original, but I think that
would be darn expensive, no?

I also considered using a vector instead of a queue, so I can iterate
through and erase as I need to, but isn't a vector more expensive,
especially since I am looking at the front and erasing in random

Any other ideas for a more efficient event queue?

Your description is somewhat vague. Why can't you delay popping the
queue until after you've determined that the event was successfully
handled? Are you handling multiple events concurrently? If you really
need to put things back into the queue, have you looked at std::deque?


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