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| author | Michael Niedermayer <michael@niedermayer.cc> | 2015-09-03 02:17:24 +0200 |
|---|---|---|
| committer | Michael Niedermayer <michael@niedermayer.cc> | 2015-11-12 02:55:46 +0100 |
| commit | 03ef13889c1965c5b5f5d383815438389695a2a4 (patch) | |
| tree | ce314ab0f1fba546396d347c8edd30ff1bbcaa51 | |
| parent | ab3f129011710d308846d072365c4678a84d76bd (diff) | |
| download | ffmpeg-03ef13889c1965c5b5f5d383815438389695a2a4.tar.gz | |
avutil/common: Add FFNABS()
This macro avoids the undefined corner case with the *_MIN values
Previous version Reviewed-by: Ganesh Ajjanagadde <gajjanag@mit.edu>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
(cherry picked from commit d6cd614dac579850076ae312c29c4188f8659e46)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
| -rw-r--r-- | libavutil/common.h | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/libavutil/common.h b/libavutil/common.h index 14343d977b..38eae28d2a 100644 --- a/libavutil/common.h +++ b/libavutil/common.h @@ -63,10 +63,19 @@ * Absolute value, Note, INT_MIN / INT64_MIN result in undefined behavior as they * are not representable as absolute values of their type. This is the same * as with *abs() + * @see FFNABS() */ #define FFABS(a) ((a) >= 0 ? (a) : (-(a))) #define FFSIGN(a) ((a) > 0 ? 1 : -1) +/** + * Negative Absolute value. + * this works for all integers of all types. + * As with many macros, this evaluates its argument twice, it thus must not have + * a sideeffect, that is FFNABS(x++) has undefined behavior. + */ +#define FFNABS(a) ((a) <= 0 ? (a) : (-(a))) + #define FFMAX(a,b) ((a) > (b) ? (a) : (b)) #define FFMAX3(a,b,c) FFMAX(FFMAX(a,b),c) #define FFMIN(a,b) ((a) > (b) ? (b) : (a)) |