[FFmpeg-devel] [PATCH] avutil/eval: add sgn()

[Steven Liu]

> 在 2019年10月12日，03:45，Paul B Mahol <onemda at gmail.com> 写道：
> 
> Signed-off-by: Paul B Mahol <onemda at gmail.com>
> ---
> doc/utils.texi   | 3 +++
> libavutil/eval.c | 4 ++++
> 2 files changed, 7 insertions(+)
> 
> diff --git a/doc/utils.texi b/doc/utils.texi
> index d55dd315c3..4e2e713505 100644
> --- a/doc/utils.texi
> +++ b/doc/utils.texi
> @@ -920,6 +920,9 @@ corresponding input value will be returned.
> @item round(expr)
> Round the value of expression @var{expr} to the nearest integer. For example, "round(1.5)" is "2.0".
> 
> + at item sgn(x)
> +Compute sign of @var{x}.
> +
> @item sin(x)
> Compute sine of @var{x}.
> 
> diff --git a/libavutil/eval.c b/libavutil/eval.c
> index 5da9a6d83b..48832979e2 100644
> --- a/libavutil/eval.c
> +++ b/libavutil/eval.c
> @@ -163,6 +163,7 @@ struct AVExpr {
>         e_last, e_st, e_while, e_taylor, e_root, e_floor, e_ceil, e_trunc, e_round,
>         e_sqrt, e_not, e_random, e_hypot, e_gcd,
>         e_if, e_ifnot, e_print, e_bitand, e_bitor, e_between, e_clip, e_atan2, e_lerp,
> +        e_sgn,
>     } type;
>     double value; // is sign in other types
>     union {
> @@ -197,6 +198,7 @@ static double eval_expr(Parser *p, AVExpr *e)
>         case e_ceil :  return e->value * ceil (eval_expr(p, e->param[0]));
>         case e_trunc:  return e->value * trunc(eval_expr(p, e->param[0]));
>         case e_round:  return e->value * round(eval_expr(p, e->param[0]));
> +        case e_sgn:    return e->value * FFDIFFSIGN(eval_expr(p, e->param[0]), 0);
>         case e_sqrt:   return e->value * sqrt (eval_expr(p, e->param[0]));
>         case e_not:    return e->value * (eval_expr(p, e->param[0]) == 0);
>         case e_if:     return e->value * (eval_expr(p, e->param[0]) ? eval_expr(p, e->param[1]) :
> @@ -470,6 +472,7 @@ static int parse_primary(AVExpr **e, Parser *p)
>     else if (strmatch(next, "clip"  )) d->type = e_clip;
>     else if (strmatch(next, "atan2" )) d->type = e_atan2;
>     else if (strmatch(next, "lerp"  )) d->type = e_lerp;
> +    else if (strmatch(next, "sgn"   )) d->type = e_sgn;
>     else {
>         for (i=0; p->func1_names && p->func1_names[i]; i++) {
>             if (strmatch(next, p->func1_names[i])) {
> @@ -657,6 +660,7 @@ static int verify_expr(AVExpr *e)
>         case e_sqrt:
>         case e_not:
>         case e_random:
> +        case e_sgn:
>             return verify_expr(e->param[0]) && !e->param[1];
>         case e_print:
>             return verify_expr(e->param[0])
> -- 
> 2.17.1
> 
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lgtm

Thanks
Steven