[Ffmpeg-devel] [PATCH] Use ff_eval for AVOption parsing

[Panagiotis Issaris]

Hi,

On za, 2006-09-23 at 12:33 +0200, Panagiotis Issaris wrote:
> The attached patch changes the AVOption parsing code to use ff_eval
> instead of av_strtod. As ff_eval uses av_strtod, the postfix ('k',
> 'M', ...) functionality is not lost.
>
>
> It does this, by moving av_strtod to eval.c as this is the only place
> where it is used now. Furthermore, one parser log message has been
> decreased in severness as it kept complaining about missing '(' in
> "bitexact", "fastint", etc. which are all parsed by eval now, and aren't
> errors. Parsing failures were/are indicated by NAN (the infrastructure
> was partly there, but they returned 0 not NAN). For the moment I've
> only added the QP2LAMBDA option to the eval's constants, so that
> ffmpeg -i src.avi -lmax 10*QP2LAMBDA dst.avi
> would work. After I sent a patch to migrate lmax from OptionDef to
> AVOptions that is.
> 
> One more thing is that I had to add four "if isnan returns" in the code,
> because parsing would fail (segfault in fact) if parsing continued when
> using "max", "default" or "min" as options:
> ffmpeg -i src.avi -b max dst.avi
> 
> To be able to add these escapes, I introduced a temporary variable in
> two out of four cases.
> [...]

Okay, after tracing ff_eval for too many hours, the bug in eval.c is
fixed now, so no "if ... returns" are necessary anymore.

So, this is an updated version of the older patch, with these checks
removed. Regression tests succeed.

These all work now:
ffmpeg -i src.avi -b 100k     dst.avi
ffmpeg -i src.avi -b 8*9k     dst.avi
ffmpeg -i src.avi -b default  dst.avi
ffmpeg -i src.avi -b QP2LAMDBA*10k   dst.avi 

The last one is not useful for -b, but will be for the next patches in
my queue (the ones for migrating lmax and others).

And this fails cleanly (no segfaulting or anything):
ffmpeg -i src.avi -b takis    dst.avi

 eval.c |   62 +++++++++++++++++++++++++++++++++++++++++++--
 opt.c  |   89 +++++++++++++----------------------------------------------------
 2 files changed, 78 insertions(+), 73 deletions(-)

With friendly regards,
Takis

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