Vasyl Pasternak <[email protected]> writes:
> Hi Cafe,
>
> Yesterday I played with iteratee package, and wanted to check its
> performance. I tried to count lines in a file, as Oleg in his famous
> lazy_vs_correct[1] article. The results somewhat disappointed me.
eris:benchmark greg$ time ./IterateeTest /usr/share/dict/words
234936
real 0m0.027s
user 0m0.010s
sys 0m0.015s
eris:benchmark greg$ time ./ByteStringTest /usr/share/dict/words
234936
real 0m0.024s
user 0m0.015s
sys 0m0.007s
Note also that the Bytestring I/O functions use a 32KB buffer and the
iteratee "enumFd" function uses a 4KB buffer; if the buffers were the
same the performance would be comparable. Here is my code:
------------------------------------------------------------------------
{-# LANGUAGE RankNTypes, ScopedTypeVariables #-}
import qualified Data.Iteratee.IO.Fd as I
import qualified Data.Iteratee as I
import qualified Data.Iteratee.WrappedByteString as I
import qualified Data.ByteString.Char8 as S
import System.Environment
import System.IO
count :: FilePath -> IO Int
count s = I.fileDriverFd cnt s
cnt :: (Monad m) => I.IterateeG I.WrappedByteString Char m Int
cnt = go 0
where
go n = I.IterateeG $ \ch ->
case ch of
(I.EOF Nothing) -> return $ I.Done n ch
(I.EOF (Just e)) -> return $ I.Cont cnt (Just e)
(I.Chunk (I.WrapBS s)) -> do
let n' = n + S.count '\n' s
return $ I.Cont (go n') Nothing
main :: IO ()
main = do
[f] <- getArgs
print =<< count f
--
Gregory Collins <[email protected]>
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