[FFmpeg-devel] [PATCH] eval: print() support

[Alexander Strasser]

Stefano Sabatini wrote:
> On date Friday 2013-01-25 17:52:37 +0100, Michael Niedermayer encoded:
> > This allows printing values via av_log from expressions.
> > 
> > Signed-off-by: Michael Niedermayer <michaelni at gmx.at>
> > ---
> >  doc/eval.texi    |    3 +++
> >  libavutil/eval.c |   12 +++++++++++-
> >  2 files changed, 14 insertions(+), 1 deletion(-)
> > 
> > diff --git a/doc/eval.texi b/doc/eval.texi
> > index f77b87d..04ab408 100644
> > --- a/doc/eval.texi
> > +++ b/doc/eval.texi
> > @@ -133,6 +133,9 @@ Return 1.0 if @var{expr} is zero, 0.0 otherwise.
> >  Compute the power of @var{x} elevated @var{y}, it is equivalent to
> >  "(@var{x})^(@var{y})".
> >  
> > + at item print(t) print(t, l)
> 
> @item print(t)
> @item print(t, l)
> 
> > +Prints t with loglevel l
> 
> Print the value of expression in @var{t} with loglevel @var{l}. If

  s/in //

> @var{l} is not specified etc...
> Return etc...
> 
> > +
> >  @item random(x)
> >  Return a pseudo random value between 0.0 and 1.0. @var{x} is the index of the
> >  internal variable which will be used to save the seed/state.
> > diff --git a/libavutil/eval.c b/libavutil/eval.c
> > index 22b491f..bd5700a 100644
> > --- a/libavutil/eval.c
> > +++ b/libavutil/eval.c
> > @@ -144,7 +144,7 @@ struct AVExpr {
> >          e_pow, e_mul, e_div, e_add,
> >          e_last, e_st, e_while, e_taylor, e_root, e_floor, e_ceil, e_trunc,
> >          e_sqrt, e_not, e_random, e_hypot, e_gcd,
> > -        e_if, e_ifnot,
> > +        e_if, e_ifnot, e_print,
> >      } type;
> >      double value; // is sign in other types
> >      union {
> > @@ -184,6 +184,12 @@ static double eval_expr(Parser *p, AVExpr *e)
> >                                            e->param[2] ? eval_expr(p, e->param[2]) : 0);
> >          case e_ifnot:  return e->value * (!eval_expr(p, e->param[0]) ? eval_expr(p, e->param[1]) :
> >                                            e->param[2] ? eval_expr(p, e->param[2]) : 0);
> > +        case e_print: {
> > +            double x = eval_expr(p, e->param[0]);
> > +            int level = e->param[1] ? av_clip(eval_expr(p, e->param[1]), INT_MIN, INT_MAX) : AV_LOG_INFO;
> > +            av_log(p, level, "%f\n", x);
> > +            return x;
> > +        }
> >          case e_random:{
> >              int idx= av_clip(eval_expr(p, e->param[0]), 0, VARS-1);
> >              uint64_t r= isnan(p->var[idx]) ? 0 : p->var[idx];
> > @@ -409,6 +415,7 @@ static int parse_primary(AVExpr **e, Parser *p)
> >      else if (strmatch(next, "sqrt"  )) d->type = e_sqrt;
> >      else if (strmatch(next, "not"   )) d->type = e_not;
> >      else if (strmatch(next, "pow"   )) d->type = e_pow;
> > +    else if (strmatch(next, "print" )) d->type = e_print;
> >      else if (strmatch(next, "random")) d->type = e_random;
> >      else if (strmatch(next, "hypot" )) d->type = e_hypot;
> >      else if (strmatch(next, "gcd"   )) d->type = e_gcd;
> > @@ -601,6 +608,9 @@ static int verify_expr(AVExpr *e)
> >          case e_not:
> >          case e_random:
> >              return verify_expr(e->param[0]) && !e->param[1];
> > +        case e_print:
> > +            return verify_expr(e->param[0])
> > +                   && (!e->param[1] || verify_expr(e->param[1]));
> 
> Missing micro bump, LGTM otherwise, although I'm not sure what this
> would be exactly useful for.

  Maybe debugging/tracing?


  Alexander