[FFmpeg-devel] [PATCH 03/12] mdct: remove temporary array in ff_kbd_window_init()
Thu Jun 24 02:58:04 CEST 2010
Michael Niedermayer <michaelni at gmx.at> writes:
> 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  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
> 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.
Try to be serious for once. If I read that correctly, you're saying
you don't know of anything that would need a larger window, and are
certainly not working on any such code at the moment. I therefor
propose setting the max size to 1024 and stating this clearly with a
comment and a #define. If we ever need it larger, we can deal with it
mans at mansr.com
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