[Vorbis-dev] lookup.c

Ralph Giles giles at xiph.org
Wed Apr 13 09:23:14 PDT 2005


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


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