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>
This commit is contained in:
Michael Niedermayer 2015-09-03 02:17:24 +02:00
parent d1bdaf3fb2
commit d6cd614dac
1 changed files with 9 additions and 0 deletions

View File

@ -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))