[FFmpeg-cvslog] alac: adjust conditions for updating entropy decoder history

[Justin Ruggles]

ffmpeg | branch: master | Justin Ruggles <justin.ruggles at gmail.com> | Mon Jul  9 10:42:52 2012 -0400| [6fd8a28b596760b4b0a2f227c54d7315e04c396a] | committer: Justin Ruggles

alac: adjust conditions for updating entropy decoder history

avoids some unnecessary arithmetic in certain situations

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=6fd8a28b596760b4b0a2f227c54d7315e04c396a
---

 libavcodec/alac.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/libavcodec/alac.c b/libavcodec/alac.c
index 84f7e42..f27992d 100644
--- a/libavcodec/alac.c
+++ b/libavcodec/alac.c
@@ -131,11 +131,11 @@ static void bastardized_rice_decompress(ALACContext *alac,
         sign_modifier = 0;
 
         /* now update the history */
-        history += x_modified * rice_history_mult -
-                    ((history * rice_history_mult) >> 9);
-
         if (x_modified > 0xffff)
             history = 0xffff;
+        else
+            history += x_modified * rice_history_mult -
+                        ((history * rice_history_mult) >> 9);
 
         /* special case: there may be compressed blocks of 0 */
         if ((history < 128) && (output_count+1 < output_size)) {