On Sun, 25 Sep 2011 07:05:34 -0400, Nick Sabalausky <[email protected]> wrote:
"Jonathan M Davis" <[email protected]> wrote in message
news:[email protected]...
On Sunday, September 25, 2011 03:18:29 Andrew Wiley wrote:
Isn't this exactly what assumeSafeAppend is for?
Hmm, I didn't know about that. (Actually, I remember hearing it mentioned
before, but then totally forgot about it.)
and if you're using assumeSafeAppend, then you
need to guarantee that nowhere else has a reference to that array
(otherwise
it's _not_ safe to assume that it's safe to append)
Would the consequences of failing to do that be any worse (or any
different
at all?) than what I mentioned about:
"One caveat about this method: If you save a slice of the stack, pop
elements off the stack, and then push new values back on, the old slice
you
took will likely reflect the new values, not the original ones."
...?
The caveat is the same, however, you should continue doing it the way you
are doing it. Using the runtime is somewhat magic, and there is a cost
for being that magical -- too many runtime calls :)
Every call to capacity and assumeSafeAppend *cannot* be inlined or
optimized, since they end up calling extern(C) function prototypes.
BTW, if you want to compare your performance with a stack implementation
that uses assumeSafeAppend, try out dcollections' ArrayList, in which
popBack does use assumeSafeAppend.
-Steve
