A queue of timed events.

A timed event is a callback function encapsulated by a TDeltaTimerEntry object, and is intended to be called when the time interval represented by the event expires.

The queue itself is a TDeltaQue list. A timed event entry is added into a position in the queue that is determined by the time interval specified for that event. Although the time interval for a timed event is specified as an interval from the present moment, when added to the queue the implementation treats each event as having an interval from the previous timed event (or now).

CDeltaTimer is an active object, driven by an RTimer which is usually set to expire upon completion of the event at the head of the queue. If the time to the next event is too great or an event at the head of the queue has been removed, the timer may be set to expire prior to the event at the head of the queue (if any).

When the timer completes, the head of the queue is inspected to see whether the timed event at the head of the queue has expired. On expiry, the callback function represented by that timed event is called, and the timed event entry is removed from the queue. The queue then inspects further events for expiry, calling and removing them as necessary until either the queue is empty or there is an event in the future to wait for.

Note that the tick period is the minimum time interval for an event and the granularity of all timings using the queue. Note that in general, any event may be called back some time after it has expired and that specifically the duration of all events will at least be rounded up to a muliple of the tick period.

TDeltaTimerEntry TDeltaQue RTimer