avcodec/apedec: fix undefined left shifts of negative numbers
authorGanesh Ajjanagadde <gajjanagadde@gmail.com>
Sun, 20 Sep 2015 02:18:54 +0000 (22:18 -0400)
committerMichael Niedermayer <michael@niedermayer.cc>
Tue, 29 Sep 2015 13:05:38 +0000 (15:05 +0200)
This fixes -Wshift-negative-value reported with clang 3.7+, e.g
http://fate.ffmpeg.org/log.cgi?time=20150919172459&log=compile&slot=x86_64-darwin-clang-polly-notiling-3.7.
Note that the patch crucially depends on int >= 32 bits,
an assumption made in many places in the codebase.

Signed-off-by: Ganesh Ajjanagadde <gajjanagadde@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
libavcodec/apedec.c

index 5536e0f..7b34d26 100644 (file)
@@ -1281,7 +1281,7 @@ static void do_apply_filter(APEContext *ctx, int version, APEFilter *f,
             /* Update the adaption coefficients */
             absres = FFABS(res);
             if (absres)
-                *f->adaptcoeffs = ((res & (-1<<31)) ^ (-1<<30)) >>
+                *f->adaptcoeffs = ((res & (-(1<<31))) ^ (-(1<<30))) >>
                                   (25 + (absres <= f->avg*3) + (absres <= f->avg*4/3));
             else
                 *f->adaptcoeffs = 0;