[FFmpeg-devel] [PATCH 2/4] avcodec/xbmenc: Pre-compute variables once for parse_str_int()
Jose Da Silva
digital at joescat.com
Mon Feb 1 05:50:57 EET 2021
Some compilers are very intuitive, and others are not so much, so let's
pre-compute the variables e and keylen outside the for loop. Ensuring a
minor speed increase regardless of if compiler is smart enough to solve
this improvement for itself, or not.
Signed-off-by: Joe Da Silva <digital at joescat.com>
---
libavcodec/xbmdec.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/libavcodec/xbmdec.c b/libavcodec/xbmdec.c
index 2ce70204cf..b783d5abe5 100644
--- a/libavcodec/xbmdec.c
+++ b/libavcodec/xbmdec.c
@@ -39,11 +39,14 @@ static int convert(uint8_t x)
static int parse_str_int(const uint8_t *p, const uint8_t *end, const uint8_t *key)
{
- for(; p<end - strlen(key); p++) {
- if (!memcmp(p, key, strlen(key)))
+ int keylen = strlen(key);
+ const uint8_t *e = end - keylen;
+
+ for(; p < e; p++) {
+ if (!memcmp(p, key, keylen))
break;
}
- p += strlen(key);
+ p += keylen;
if (p >= end)
return INT_MIN;
--
2.30.0
More information about the ffmpeg-devel
mailing list