diff options
| author | Stefano Sabatini <stefasab@gmail.com> | 2012-01-15 22:59:42 +0100 |
|---|---|---|
| committer | Stefano Sabatini <stefasab@gmail.com> | 2012-01-17 12:03:30 +0100 |
| commit | 999495734b9de597f59590708979902f28ebce61 (patch) | |
| tree | 5d7bf9d6735a8aea4b5d93f8ed481eed738fc950 /libavutil/eval.c | |
| parent | a798c20a76196d76db27f7446ab90f8062f3c4eb (diff) | |
lavu/eval: add if() and ifnot() eval functions
They allow to implement the if/then/else logic, which cannot be
implemented otherwise.
For example the expression:
A*B + not(A)*C
always evaluates to NaN if B is NaN, even in the case where A is 0.
Diffstat (limited to 'libavutil/eval.c')
| -rw-r--r-- | libavutil/eval.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/libavutil/eval.c b/libavutil/eval.c index 1b8176c505..2ee3965e7c 100644 --- a/libavutil/eval.c +++ b/libavutil/eval.c @@ -136,6 +136,7 @@ struct AVExpr { e_pow, e_mul, e_div, e_add, e_last, e_st, e_while, e_floor, e_ceil, e_trunc, e_sqrt, e_not, e_random, e_hypot, e_gcd, + e_if, e_ifnot, } type; double value; // is sign in other types union { @@ -165,6 +166,8 @@ static double eval_expr(Parser *p, AVExpr *e) case e_trunc: return e->value * trunc(eval_expr(p, e->param[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]) : 0); + case e_ifnot: return e->value * (!eval_expr(p, e->param[0]) ? eval_expr(p, e->param[1]) : 0); 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]; @@ -324,6 +327,8 @@ static int parse_primary(AVExpr **e, Parser *p) 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; + else if (strmatch(next, "if" )) d->type = e_if; + else if (strmatch(next, "ifnot" )) d->type = e_ifnot; else { for (i=0; p->func1_names && p->func1_names[i]; i++) { if (strmatch(next, p->func1_names[i])) { @@ -690,6 +695,9 @@ int main(int argc, char **argv) "pow(PI,1.23)", "PI^1.23", "pow(-1,1.23)", + "if(1, 2)", + "ifnot(0, 23)", + "ifnot(1, NaN) + if(0, 1)", NULL }; |