Re: my Bidi implementation

[Behdad Esfahbod <behdad at cs dot toronto dot edu>]

On Sat, 13 Mar 2004 dov at imagic dot weizmann dot ac dot il wrote:

> It just shows how detached I am from the code these days. ;-) I
> should be more careful with you on the list.
>
> Finding the *optimal* 9 layer lookup sounds like a really tough
> optimization problem. I guess I'll have a look at the code to
> see what you did. It would be even more interesting finding the
> optimal combination between "if"-statements and lookups
> automatically. But I'm getting carried away.
>
> Dov

It's a backtrack, optimized with a couple of bounds.  It used to
take a minute to find that, but right now on my laptop, it took
less than 10 seconds.  There is no "if" statement, just a simple
lookup.  Looks like this:

#define FRIBIDI_GET_TYPE(x)     \
        FriBidiPropertyBlockLevel8[(x)%2 +      \
        FriBidiPropertyBlockLevel7[(x)/2%2 +    \
        FriBidiPropertyBlockLevel6[(x)/4%8 +    \
        FriBidiPropertyBlockLevel5[(x)/32%2 +   \
        FriBidiPropertyBlockLevel4[(x)/64%4 +   \
        FriBidiPropertyBlockLevel3[(x)/256%8 +  \
        FriBidiPropertyBlockLevel2[(x)/2048%4 + \
        FriBidiPropertyBlockLevel1[(x)/8192%8 + \
        FriBidiPropertyBlockLevel0[(x)/65536]]]]]]]]]


cool? ;)
behdad