[FFmpeg-devel] [PATCH 1/2] avutil/common: add FFUABSDIFF macro

[Ganesh Ajjanagadde]

FFUABSDIFF(a,b) returns |a-b|.
It is designed to guarantee the correct result for unsigned operands a and b,
while with integer operands overflow may occur depending on how it is used.
This macro is useful across at least 3 places in the codebase,
and is therefore placed in avutil/common.

Signed-off-by: Ganesh Ajjanagadde <gajjanagadde at gmail.com>
---
 libavutil/common.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/libavutil/common.h b/libavutil/common.h
index 3e62b6d..eab7ed2 100644
--- a/libavutil/common.h
+++ b/libavutil/common.h
@@ -59,6 +59,7 @@
 #define FFUDIV(a,b) (((a)>0 ?(a):(a)-(b)+1) / (b))
 #define FFUMOD(a,b) ((a)-(b)*FFUDIV(a,b))
 #define FFABS(a) ((a) >= 0 ? (a) : (-(a)))
+#define FFUABSDIFF(a,b) (((a) > (b)) ? ((a)-(b)) : ((b)-(a)))
 #define FFSIGN(a) ((a) > 0 ? 1 : -1)
 
 #define FFMAX(a,b) ((a) > (b) ? (a) : (b))
-- 
2.5.0