[FFmpeg-devel] [PATCH 6/7] Implement if(expr, cond) binary function evaluation.
Stefano Sabatini
stefano.sabatini-lala
Mon Nov 1 00:23:32 CET 2010
---
doc/eval.texi | 5 +++++
libavutil/eval.c | 11 ++++++++++-
2 files changed, 15 insertions(+), 1 deletions(-)
diff --git a/doc/eval.texi b/doc/eval.texi
index 2416442..c944b3e 100644
--- a/doc/eval.texi
+++ b/doc/eval.texi
@@ -56,6 +56,11 @@ The function returns the loaded value.
Evaluate expression @var{expr} when the expression @var{cond} is
true, and returns the value of the last @var{expr} evaluation, or NAN
if @var{cond} was always false.
+
+ at item if(cond, expr)
+Evaluate expression @var{expr} only if the expression @var{cond} is
+true, and returns the value of the last @var{expr} evaluation, or NAN
+if @var{cond} was false.
@end table
It is possible to define more unary and binary functions used in an
diff --git a/libavutil/eval.c b/libavutil/eval.c
index 97af022..83e602d 100644
--- a/libavutil/eval.c
+++ b/libavutil/eval.c
@@ -121,7 +121,7 @@ struct AVExpr {
e_squish, e_gauss, e_ld,
e_mod, e_max, e_min, e_eq, e_gt, e_gte,
e_pow, e_mul, e_div, e_add,
- e_last, e_st, e_while,
+ e_last, e_st, e_while, e_if,
} type;
double value; // is sign in other types
union {
@@ -150,6 +150,12 @@ static double eval_expr(Parser *p, AVExpr *e)
d=eval_expr(p, e->param[1]);
return d;
}
+ case e_if: {
+ double d = NAN;
+ if (eval_expr(p, e->param[0]))
+ d=eval_expr(p, e->param[1]);
+ return d;
+ }
default: {
double d = eval_expr(p, e->param[0]);
double d2 = eval_expr(p, e->param[1]);
@@ -274,6 +280,7 @@ static int parse_primary(AVExpr **e, Parser *p)
else if (strmatch(next, "ld" )) d->type = e_ld;
else if (strmatch(next, "st" )) d->type = e_st;
else if (strmatch(next, "while" )) d->type = e_while;
+ else if (strmatch(next, "if" )) d->type = e_if;
else {
for (i=0; p->func1_names && p->func1_names[i]; i++) {
if (strmatch(next, p->func1_names[i])) {
@@ -574,6 +581,8 @@ int main(void)
"st(1, 1); st(2, 2); st(0,1); while(lte(ld(0),10), st(3, ld(1)+ld(2)); st(1, ld(2)); st(2, ld(3)); st(0, ld(0)+1)); ld(3)",
"while(0, 10)",
"st(0, 1); while(lte(ld(0),100), st(1, ld(1)+ld(0));st(0, ld(0)+1))",
+ "if(1, 123)",
+ "if(eq(0,1), 123)",
NULL
};
--
1.7.1
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