[FFmpeg-cvslog] MK(BE)TAG: avoid undefined shifts

[Mans Rullgard]

ffmpeg | branch: master | Mans Rullgard <mans at mansr.com> | Thu Nov 24 23:15:59 2011 +0000| [6b34fbba9b73e1914d56c2aff96356326002430d] | committer: Mans Rullgard

MK(BE)TAG: avoid undefined shifts

Casting the left-most byte to unsigned avoids an undefined
result of the shift by 24 if bit 7 is set.  This affects
the rm demuxer.

Signed-off-by: Mans Rullgard <mans at mansr.com>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=6b34fbba9b73e1914d56c2aff96356326002430d
---

 libavutil/common.h |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/libavutil/common.h b/libavutil/common.h
index 9691f5b..7e93a1a 100644
--- a/libavutil/common.h
+++ b/libavutil/common.h
@@ -218,8 +218,8 @@ static av_always_inline av_const int av_popcount_c(uint32_t x)
     return (x + (x >> 16)) & 0x3F;
 }
 
-#define MKTAG(a,b,c,d) ((a) | ((b) << 8) | ((c) << 16) | ((d) << 24))
-#define MKBETAG(a,b,c,d) ((d) | ((c) << 8) | ((b) << 16) | ((a) << 24))
+#define MKTAG(a,b,c,d) ((a) | ((b) << 8) | ((c) << 16) | ((unsigned)(d) << 24))
+#define MKBETAG(a,b,c,d) ((d) | ((c) << 8) | ((b) << 16) | ((unsigned)(a) << 24))
 
 /**
  * Convert a UTF-8 character (up to 4 bytes) to its 32-bit UCS-4 encoded form.