[FFmpeg-devel] avformat/lrcdec: fix losing opening bracket

[Michael Niedermayer]

On Fri, Jul 13, 2018 at 01:34:47PM +0530, Umair Khan wrote:
> On Wed, Jul 11, 2018 at 11:07 PM Michael Niedermayer
> <michael at niedermayer.cc> wrote:
> >
> > On Tue, Jul 10, 2018 at 08:10:00PM +0530, Umair Khan wrote:
> > > Hi,
> > >
> > > Patch attached.
> > >
> > > -Umair
> >
> > >  lrcdec.c |    3 +++
> > >  1 file changed, 3 insertions(+)
> > > 6782b07bfa45139361c15527ee5fb78e5893b9ba  0001-avformat-lrcdec-fix-losing-opening-bracket.patch
> > > From 95a5d2e5575c5f895e4251775a48f7deb4c86124 Mon Sep 17 00:00:00 2001
> > > From: Umair Khan <omerjerk at gmail.com>
> > > Date: Tue, 10 Jul 2018 19:51:41 +0530
> > > Subject: [PATCH 1/1] avformat/lrcdec: fix losing opening bracket
> > >
> > > Fixes #7255
> > >
> > > Signed-off-by: Umair Khan <omerjerk at gmail.com>
> > > ---
> > >  libavformat/lrcdec.c | 3 +++
> > >  1 file changed, 3 insertions(+)
> > >
> > > diff --git a/libavformat/lrcdec.c b/libavformat/lrcdec.c
> > > index f4e9a4efa9..d1e28aff87 100644
> > > --- a/libavformat/lrcdec.c
> > > +++ b/libavformat/lrcdec.c
> > > @@ -68,6 +68,9 @@ static int64_t count_ts(const char *p)
> > >                   (p[offset] >= '0' && p[offset] <= '9'))) {
> > >              offset++;
> > >          } else {
> > > +            if (in_brackets) {
> > > +                --offset;
> > > +            }
> > >              break;
> >
> > this is probably ok but it doesnt fix this completely
> >
> > consider 2 [[
> > or a [123
> >
> > The code should probably remember the last position after a correctly
> > parsed timestamp or maybe use sscanf() to parse these timestamps
> 
> The new attached patch takes care of these cases.
> 
> > Also it seems the code doesnt handle timestamps in the middle of lines
> > (not related to your patch though)
> 
> I can handle this case if you can give me an example of what case you
> are talking about exactly.
> 
> -Umair

>  lrcdec.c |    7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 72feffd56541236991001caaa92e533382b98b53  0001-avformat-lrcdec-fix-losing-opening-bracket.patch
> From 81c2e13aa0a7559886502cfb69f788bd0de7a64a Mon Sep 17 00:00:00 2001
> From: Umair Khan <omerjerk at gmail.com>
> Date: Fri, 13 Jul 2018 13:24:51 +0530
> Subject: [PATCH 1/1] avformat/lrcdec: fix losing opening bracket
> 
> ---
>  libavformat/lrcdec.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/libavformat/lrcdec.c b/libavformat/lrcdec.c
> index f4e9a4efa9..4093cbdf10 100644
> --- a/libavformat/lrcdec.c
> +++ b/libavformat/lrcdec.c
> @@ -60,14 +60,15 @@ static int64_t count_ts(const char *p)
>          } else if(p[offset] == '[') {
>              offset++;
>              in_brackets++;
> -        } else if (p[offset] == ']' && in_brackets) {
> -            offset++;
> -            in_brackets--;
>          } else if(in_brackets &&
>                   (p[offset] == ':' || p[offset] == '.' || p[offset] == '-' ||
>                   (p[offset] >= '0' && p[offset] <= '9'))) {
>              offset++;
>          } else {
> +            if (p[offset] == ']' && in_brackets) {
> +                offset++;
> +                in_brackets--;
> +            }
>              break;

This breaks multiple times like:
[00:35.62][00:35.63][00:35.64][[[[123 is a number

this should be interpreted as 3 occurances of "[[[[123 is a number" IIUC

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

The educated differ from the uneducated as much as the living from the
dead. -- Aristotle 
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