Thank you! Your right, of course, about unloading the array.
(I guess I was just using the index array again because I had it.)
Note that it would actually be: 
  @all = @a < $sz  ?  @a  :  @a[ $tl+1 .. $top, 0 .. $tl ];

[download]
since $tl ("tail") is left pointing at the last item written.

About replacing the memory access with a modulo operation:
Maybe. But modulo ain't cheap and at least for small $sz's,
the memory access may not be one (caches). The whole point of
the exercise was to avoid the slowdown from the
shift @a if @a == $sz;

[download]
test in the canonical loop. Modulo would seem to be in the same
class. On the Solaris I'm working on at the moment, the indexed
index is much faster than modulo, at least up to arrays of 3000.
In fact, the modulo is only marginally faster than shift/push.

Oddly, the direct retrieval seems to take about as long as retrieving
through the index array(!?!), but it certainly is clearer,
thanks again,


p

In reply to Re: Re: Circular buffer instead of shift/push by petral
in thread Circular buffer instead of shift/push by petral

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