[FFmpeg-cvslog] avutil/common: Fix undefined shift

Andreas Rheinhardt git at videolan.org
Thu Sep 19 01:09:37 EEST 2019


ffmpeg | branch: master | Andreas Rheinhardt <andreas.rheinhardt at gmail.com> | Wed Sep 18 05:26:07 2019 +0200| [ebd25a5ba532633326d3944eda2e982380ef6626] | committer: Michael Niedermayer

avutil/common: Fix undefined shift

av_mod_uintp2_c uses a bitwise AND with (1 << p) - 1 to clear the high
bits of an unsigned int. But this is undefined if p == 31, because 1 is
an int and 2^31 is not representable in an int. So make 1 unsigned.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at gmail.com>
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=ebd25a5ba532633326d3944eda2e982380ef6626
---

 libavutil/common.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavutil/common.h b/libavutil/common.h
index 8db0291170..af35397eb9 100644
--- a/libavutil/common.h
+++ b/libavutil/common.h
@@ -240,7 +240,7 @@ static av_always_inline av_const unsigned av_clip_uintp2_c(int a, int p)
  */
 static av_always_inline av_const unsigned av_mod_uintp2_c(unsigned a, unsigned p)
 {
-    return a & ((1 << p) - 1);
+    return a & ((1U << p) - 1);
 }
 
 /**



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