[FFmpeg-devel] [PATCH 1/2] avutil/video_enc_params: Combine overflow checks

[Andreas Rheinhardt]

This patch also fixes a -Wtautological-constant-out-of-range-compare
warning from Clang and a -Wtype-limits warning from GCC on systems
where size_t is 64bits and unsigned 32bits. The reason for this seems
to be that variable (whose value derives from sizeof() and can therefore
be known at compile-time) is used instead of using sizeof() directly in
the comparison.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at gmail.com>
---
Using (UINT_MAX > SIZE_MAX / sizeof(AVVideoBlockParams) && nb_blocks >
SIZE_MAX / sizeof(AVVideoBlockParams)) would have fixed the warning with
Clang, but not GCC.

 libavutil/video_enc_params.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/libavutil/video_enc_params.c b/libavutil/video_enc_params.c
index c46c0f1dc6..b9cdafddbb 100644
--- a/libavutil/video_enc_params.c
+++ b/libavutil/video_enc_params.c
@@ -33,8 +33,7 @@ AVVideoEncParams *av_video_enc_params_alloc(enum AVVideoEncParamsType type,
     size_t size;
 
     size = sizeof(*par);
-    if (nb_blocks > SIZE_MAX / sizeof(AVVideoBlockParams) ||
-        nb_blocks * sizeof(AVVideoBlockParams) > SIZE_MAX - size)
+    if (nb_blocks > (SIZE_MAX - size) / sizeof(AVVideoBlockParams))
         return NULL;
     size += sizeof(AVVideoBlockParams) * nb_blocks;
 
-- 
2.27.0