Add av_compare_mod()

Originally committed as revision 23551 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 9 insertions, 0 deletions

diff --git a/libavutil/mathematics.h b/libavutil/mathematics.h
index e198aef8cb..889ce959fd 100644
--- a/libavutil/mathematics.h
+++ b/libavutil/mathematics.h
@@ -94,5 +94,14 @@ int64_t av_rescale_q(int64_t a, AVRational bq, AVRational cq) av_const;
  */
 int av_compare_ts(int64_t ts_a, AVRational tb_a, int64_t ts_b, AVRational tb_b);
 
+/**
+ * Compare 2 integers modulo mod.
+ * That is we compare integers a and b for which only the least significant log2(mod) bits are known
+ * @param mod must be a power of 2
+ * @returns a negative value if a is smaller than b
+ *          a positiv  value if a is greater than b
+ *          0                if a equals          b
+ */
+int64_t av_compare_mod(uint64_t a, uint64_t b, uint64_t mod);
 
 #endif /* AVUTIL_MATHEMATICS_H */