[Haskell-cafe] Slow IO?

[Don Stewart]

Good work guys.

If you can abstract out a common function for lexing ints out of
bytestrings, we could add it to the bytestring-lexing package.

ekirpichov:
> Hm, on my machine Don's code has exactly the same performance my code above.
> 
> Also, replacing the 'test' and 'parse' functions with this one
> 
> add :: Int -> Int -> S.ByteString -> Int
> add k i s = fst $ S.foldl' f (i, 0) s
>   where f (!i, !n) '\n' | n`divisibleBy`k = (i+1, 0)
>                         | otherwise       = (i,   0)
>         f (!i, !n) w  = (i, 10*n+ord w-ord '0')
> 
> increases performance by another 15% (0.675s vs 0.790s)
> 
> 2009/9/1 Jason Dusek <jason.dusek at gmail.com>:
> >  I've updated Don Stewart's solution to compile with the modern
> >  ByteString libs. I'll be looking at ways to improve the
> >  performance of the `bytestring-nums` package.
> >
> > --
> > Jason Dusek
> >
> >
> > http://github.com/jsnx/bytestring-nums/blob/d7de9db83e44ade9958fb3bfad0b29ede065b5dd/SPOJDons.hs
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> 
> 
> 
> -- 
> Eugene Kirpichov
> Web IR developer, market.yandex.ru
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