Add function to compute ceil(log2(x)).

Patch by Thilo Borgmann <thilo.borgmann _at_ googlemail.com>

Originally committed as revision 19747 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Thilo Borgmann 2009-08-30 15:50:03 +00:00 committed by Justin Ruggles
parent 1369582777
commit c6dbbc4576

View File

@ -225,6 +225,15 @@ static inline av_const float av_clipf(float a, float amin, float amax)
else return a; else return a;
} }
/** Computes ceil(log2(x)).
* @param x value used to compute ceil(log2(x))
* @return computed ceiling of log2(x)
*/
static inline av_const int av_ceil_log2(int x)
{
return av_log2((x - 1) << 1);
}
#define MKTAG(a,b,c,d) (a | (b << 8) | (c << 16) | (d << 24)) #define MKTAG(a,b,c,d) (a | (b << 8) | (c << 16) | (d << 24))
#define MKBETAG(a,b,c,d) (d | (c << 8) | (b << 16) | (a << 24)) #define MKBETAG(a,b,c,d) (d | (c << 8) | (b << 16) | (a << 24))