On Thu, Oct 31, 2019 at 07:38:00AM +0000, Andreas Rheinhardt wrote: > Andreas Rheinhardt: > > Carl Eugen Hoyos: > >> Am Fr., 20. Sept. 2019 um 00:30 Uhr schrieb Andreas Rheinhardt > >> <andreas.rheinha...@gmail.com>: > >>> > >>> Fixes lots of FATE tests, e.g. lavf-nut, as well as the nut part of > >>> ticket #7980. > >>> > >>> Signed-off-by: Andreas Rheinhardt <andreas.rheinha...@gmail.com> > >>> --- > >>> This patch is made to match the previous behaviour; whether the previous > >>> behaviour is correct at all if the header length is zero is unknown to > >>> me. > >>> > >>> libavformat/nutenc.c | 5 +++-- > >>> 1 file changed, 3 insertions(+), 2 deletions(-) > >>> > >>> diff --git a/libavformat/nutenc.c b/libavformat/nutenc.c > >>> index e9a3bb49db..dc714eb809 100644 > >>> --- a/libavformat/nutenc.c > >>> +++ b/libavformat/nutenc.c > >>> @@ -791,8 +791,9 @@ static int get_needed_flags(NUTContext *nut, > >>> StreamContext *nus, FrameCode *fc, > >>> flags |= FLAG_CHECKSUM; > >>> if (pkt->size < nut->header_len[fc->header_idx] || > >>> (pkt->size > 4096 && fc->header_idx) || > >>> - memcmp(pkt->data, nut->header[fc->header_idx], > >>> - nut->header_len[fc->header_idx])) > >>> + (nut->header_len[fc->header_idx] > 0 && > >>> + memcmp(pkt->data, nut->header[fc->header_idx], > >>> + nut->header_len[fc->header_idx]))) > >>> flags |= FLAG_HEADER_IDX; > >> > >> Is this different from the patch I sent? > >> (Why does it look different) > >> https://patchwork.ffmpeg.org/patch/13782/ > >> > >> Carl Eugen > > > > Yes. > > a) Your patch checks whether nut->header[fc->header_idx] is NULL. > > b) Michael's proposal is to check for fc->header_idx instead. This > > would work, because it is the index of the only used pointer in > > nut->header that is NULL, and this proposal has the advantage of one > > dereferencing less than a). > > c) My* patch checks whether nut->header_len[fc->header_idx] is zero. > > Given that nut->header_len[fc->header_idx] is already used in the very > > first check, my solution should not entail a dereference at all. > > > > Furthermore, b) is very specific to the nutenc situation here and a) > > might hide a situation where nut->header_len[fc->header_idx] is > 0, > > but nut->header[fc->header_idx] == NULL, which should of course not > > happen. And it singles out one of the two pointer arguments. > > > > - Andreas > > > > *: It is also what Reimar proposed (I was completely unaware of the > > earlier patch when I submitted mine). > > > Ping.
I dont think the resulting code is particularly readable with the increasingly complex condition in the if() ill post a alternative suggestion for consideration that has a simpler condition after testing it thx [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB The real ebay dictionary, page 2 "100% positive feedback" - "All either got their money back or didnt complain" "Best seller ever, very honest" - "Seller refunded buyer after failed scam"
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