Re: array index and modulo

[Enrico Colombini <erix@...>]

Ralph Hempel wrote:
> -- this needs to be atomic
> buffer[head] = "Some new data"
> head = head + 1
>
> -- this needs to be atomic
> data = buffer[tail]
> buffer[tail] = nil
> tail = tail + 1
>
> Is there a severe performance penalty for this? What happens
> when the index wraps around?

There is an interesting estimate in the PiL book. I don't remember the 
numbers, but the program would have to run for a *really* long time for 
wrap-around to happen.
In practice, it can be used safely in almost all applications.

  Enrico