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

[Stefano Sabatini]

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
@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.
-- 
FFmpeg = Fierce & Faithful Mythic Philosofic Efficient Gorilla