[FFmpeg-devel] [PATCH] Add ceil(log2(x)) to libavutil/common.h

Måns Rullgård mans
Sun Aug 23 13:07:18 CEST 2009


Thilo Borgmann <thilo.borgmann at googlemail.com> writes:

>>> +/** Computes ceil(log2(x)) using av_log2.
>>> + * @param x value used to compute ceil(log2(x))
>>> + * @param computed ceiling of log2(x)
>>> + */
>>> +static inline int ceil_log2(int x) {
>>> +    return x > 1 ? av_log2((x - 1) << 1) : 0;
>>> +}
>> 
>> if its just ceil(log2(x)) then the x >1 check should not be needed
>> and "using av_log2()" should be kept more seperate, i mean
>> API interface vs. implementation
> Please elaborate "to keep it more separate" in that case... what I it
> tells me is to duplicate the use of ff_log2_tab - what I think you don't
> mean with that.

He means you shouldn't mention av_log2 in the comment.  How the
calculation happens is irrelevant.

-- 
M?ns Rullg?rd
mans at mansr.com



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