[FFmpeg-devel] [PATCH 03/12] mdct: remove temporary array in ff_kbd_window_init()

Michael Niedermayer michaelni
Thu Jun 24 02:51:10 CEST 2010


On Thu, Jun 24, 2010 at 01:35:06AM +0100, M?ns Rullg?rd wrote:
> Michael Niedermayer <michaelni at gmx.at> writes:
> 
> > On Thu, Jun 24, 2010 at 12:37:34AM +0100, M?ns Rullg?rd wrote:
> >> Michael Niedermayer <michaelni at gmx.at> writes:
> >> 
> >> > On Wed, Jun 23, 2010 at 06:26:41PM +0100, Mans Rullgard wrote:
> >> >> The intermediate values can be stored in the output array, avoiding
> >> >> the need for a variable-length array.
> >> >
> >> > this can write into static arrays and thus introduces a race condition
> >> 
> >> Quite.  Which would you prefer then, 1) malloc/free or, 2) always
> >> allocating a [1024] array (largest size used)?  Option 2 would use 4k
> >> (float) or 8k (double) of stack space, which is IMO a bit larger than
> >> what's comfortable.  It would of course not change anything compared
> >> to current code so should be safe.
> >
> > as its speed irrelevant init code iam ok with malloc()
> 
> Using malloc complicates error handling though.  The function
> currently returns no status (since it cannot fail), and the callers
> obviously do not check it.
> 
> Since allocating a 1024-element array is fine now, it should be OK
> even if hardcoded.  Do you forsee larger sizes being required in the
> future?

The future is in perpetual motion, iam not capable to say anything
with certainity but i feel some remote danger. Maybe some dark plan of the
high comiitee or some noble warrior whos heart was not strong enough
while walking to close to darkness.
One of them might create a spec that requires a larger window.

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Many that live deserve death. And some that die deserve life. Can you give
it to them? Then do not be too eager to deal out death in judgement. For
even the very wise cannot see all ends. -- Gandalf
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