libavutil: Utility code from libavcodec moved to a separate library.

Originally committed as revision 4489 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavutil/mathematics.h

@@ -0,0 +1,31 @@
+#ifndef MATHEMATICS_H
+#define MATHEMATICS_H
+
+#include "rational.h"
+
+enum AVRounding {
+    AV_ROUND_ZERO     = 0, ///< round toward zero
+    AV_ROUND_INF      = 1, ///< round away from zero
+    AV_ROUND_DOWN     = 2, ///< round toward -infinity
+    AV_ROUND_UP       = 3, ///< round toward +infinity
+    AV_ROUND_NEAR_INF = 5, ///< round to nearest and halfway cases away from zero
+};
+
+/**
+ * rescale a 64bit integer with rounding to nearest.
+ * a simple a*b/c isn't possible as it can overflow
+ */
+int64_t av_rescale(int64_t a, int64_t b, int64_t c);
+
+/**
+ * rescale a 64bit integer with specified rounding.
+ * a simple a*b/c isn't possible as it can overflow
+ */
+int64_t av_rescale_rnd(int64_t a, int64_t b, int64_t c, enum AVRounding);
+
+/**
+ * rescale a 64bit integer by 2 rational numbers.
+ */
+int64_t av_rescale_q(int64_t a, AVRational bq, AVRational cq);
+
+#endif /* MATHEMATICS_H */