[FFmpeg-devel] [PATCH 1/3] adler32: avoid "too big" check in the inner loop

[Michael Niedermayer]

On Sat, Feb 04, 2012 at 05:43:24AM +0100, Michael Niedermayer wrote:
> On Fri, Feb 03, 2012 at 10:51:01PM +0100, Reimar Döffinger wrote:
> > 
> > 
> > On 3 Feb 2012, at 22:20, Michael Niedermayer <michaelni at gmx.at> wrote:
> > 
> > > Signed-off-by: Michael Niedermayer <michaelni at gmx.at>
> > > ---
> > > libavutil/adler32.c |   14 ++++++++++----
> > > 1 files changed, 10 insertions(+), 4 deletions(-)
> > > 
> > > diff --git a/libavutil/adler32.c b/libavutil/adler32.c
> > > index f4f56ea..9ea639f 100644
> > > --- a/libavutil/adler32.c
> > > +++ b/libavutil/adler32.c
> > > @@ -37,17 +37,23 @@ unsigned long av_adler32_update(unsigned long adler, const uint8_t * buf,
> > >     unsigned long s2 = adler >> 16;
> > > 
> > >     while (len > 0) {
> > > +        unsigned len2=(len-1) & ~15;
> > > +        if (len2 > 2048) len2 = 2048;
> > 
> > I would suggest FFALIGN and FFMIN.
> 
> i added FFMIN() but not FFALIGN because the FFALIGN operation rounds
> up and we need quite specific round down with at least 1 remaining
> here. It could be used of course but it feels quite unintuitiv to me.

and applied with these changes

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

If a bugfix only changes things apparently unrelated to the bug with no
further explanation, that is a good sign that the bugfix is wrong.
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