Vorbis dev - Apr 2005 - (no subject)

I'm not understand "lookup.c" in the "lib". Can you
explain it in detail for me?

On Wed, Apr 13, 2005 at 10:04:25PM +0800, ???? wrote:
> I'm not understand "lookup.c" in the "lib". Can you
explain it in detail for me?
This file implements lookup tables for a number of trancendental math 
functions used by the codec. The actual table data is precomputed and 
stored in static arrays defined in lookup_data.h. The functions in 
lookup.c perform linear interpolation between the accurate values 
defined in the tables. There are two versions, one set for floating 
point and one set for the integer domain.

This is purely a performance enhancement.

Hope that helps,
 -r

On 4/13/05, ?? <zhuheng@emails.bjut.edu.cn> wrote:
> I'm not understand "lookup.c" in the "lib". Can you
explain it in detail for me?
> 
What don't you understand? What this file does, or how the code is
implemented?

Briefly, it uses lookup tables to do fast (but limited accuracy)
calculations of a few functions that vorbis needs to use extensively
(generally in speed-critical areas).

Mike