public static IObservable <TSource> Shift <TSource>(
this IObservable <TSource> source,
long count,
IScheduler scheduler)
{
return(Observable.Create <TSource>(observer =>
{
var limited_queue = new FixedSizedQueue <TSource>(count);
return source.Subscribe(value =>
{
if (limited_queue.Shift(value, out var outObj))
{
observer.OnNext(outObj);
}
},
observer.OnError,
/* Immediate abort semantics of Rx requires us to propagate
* errors immediately (i.e., without draining the queue).
* (Exception ex) =>
* {
* limited_queue
* .Subscribe(Observer
* .Create<TSource>(data => observer.OnNext(data),
* () => observer.OnError(ex)),
* scheduler);
* }*/
() => { limited_queue.ToObservable(scheduler).Subscribe(observer); });
}));
}
public static IObservable <TAccumulate> WindowAggregate <TSource, TAccumulate>(
this IObservable <TSource> source,
long windowSize,
TAccumulate seed,
Func <TAccumulate, TSource, TSource, long, TAccumulate> accumulator,
Func <TAccumulate, TSource, long, long, TAccumulate> windowDrainer)
{
if (accumulator == null)
{
throw new ArgumentNullException("WindowAggregate: accumulator can't be null");
}
if (windowDrainer == null)
{
throw new ArgumentNullException("WindowAggregate: windowDrainer can't be null");
}
return(Observable.Create <TAccumulate>(observer =>
{
var limitedQueue = new FixedSizedQueue <TSource>(windowSize);
return source.Subscribe(
value =>
{
try
{
seed = limitedQueue.Shift(value, out var outObj)
? accumulator(seed, value, outObj, limitedQueue.Count)
: windowDrainer(seed, value, limitedQueue.Count, limitedQueue.Count - 1);
observer.OnNext(seed);
}
catch (Exception ex)
{
observer.OnError(ex);
}
},
observer.OnError,
() =>
{
try
{
long count = limitedQueue.Count;
while (limitedQueue.TryDequeue(out var outObj))
{
count--;
seed = windowDrainer(seed, outObj, count, count + 1);
observer.OnNext(seed);
}
if (count != 0)
{
observer.OnError(
new ApplicationException(
"WindowAggregte: OnCompleted: Unable to deque all elements"));
}
else
{
observer.OnCompleted();
}
}
catch (Exception ex)
{
observer.OnError(ex);
}
});
}));
}
