[FFmpeg-cvslog] apedec: fix signed integer overflows

[Mans Rullgard]

ffmpeg | branch: master | Mans Rullgard <mans at mansr.com> | Fri Nov 25 18:46:35 2011 +0000| [644bff6c9bf15b5ed723a893236dbc8c29579c93] | committer: Mans Rullgard

apedec: fix signed integer overflows

This bit manipulation is equivalent but avoids undefined
shifts and overflows.

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

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=644bff6c9bf15b5ed723a893236dbc8c29579c93
---

 libavcodec/apedec.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/libavcodec/apedec.c b/libavcodec/apedec.c
index 6c3d29e..7702b29 100644
--- a/libavcodec/apedec.c
+++ b/libavcodec/apedec.c
@@ -690,7 +690,7 @@ 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;