Hurr durr -- I was wondering why the left-fold numbers looked so slow, then after looking at memory profiles I realized I forgot to add strictness to the enumerator/iteratee benchmarks. Here are the corrected numbers (with benchmarks attached):
enumerator ==================== 5.414 / 2.090 / 0.360 5.415 / 1.950 / 0.320 5.429 / 2.010 / 0.360 iteratee ==================== 5.447 / 1.620 / 0.470 5.389 / 2.030 / 0.300 5.457 / 1.960 / 0.390
module Main (main) where import Data.Enumerator import Data.Enumerator.IO import qualified Data.ByteString as B import qualified Data.ByteString.Char8 as B8 import System.IO import System.Environment iterLines :: Monad m => Iteratee e B.ByteString m Integer iterLines = continue (step 0) where step acc EOF = yield acc EOF step acc (Chunks xs) = continue $ step $! foldl foldStep acc xs foldStep acc bytes = acc + countChar '\n' bytes countChar :: Char -> B.ByteString -> Integer countChar c = B8.foldl (\acc c' -> if c' == c then acc + 1 else acc) 0 main :: IO () main = do filename:_ <- getArgs h <- openBinaryFile filename ReadMode run (iterLines >>== enumHandle 4096 h) >>= print
module Main (main) where import Data.Iteratee import Data.Iteratee.IO import Data.Iteratee.WrappedByteString import Data.Word (Word8) import qualified Data.ByteString as B import qualified Data.ByteString.Char8 as B8 import System.IO import System.Environment iterLines :: Monad m => IterateeG WrappedByteString Word8 m Integer iterLines = IterateeG (step 0) where step acc s@(EOF _) = return $ Done acc s step acc (Chunk wrapped) = return $ Cont (IterateeG (step $! acc')) Nothing where acc' = acc + countChar '\n' (unWrap wrapped) countChar :: Char -> B.ByteString -> Integer countChar c = B8.foldl (\acc c' -> if c' == c then acc + 1 else acc) 0 main :: IO () main = do filename:_ <- getArgs h <- openBinaryFile filename ReadMode enumHandle h iterLines >>= run >>= print
import qualified Data.ByteString.Lazy as B import qualified Data.ByteString.Lazy.Char8 as B8 import System.IO import System.Environment countChar :: Char -> B.ByteString -> Integer countChar c = B8.foldl' (\acc c' -> if c' == c then acc + 1 else acc) 0 countHandle :: Handle -> IO Integer countHandle h = fmap (countChar '\n') (B.hGetContents h) main :: IO () main = do filename:_ <- getArgs h <- openBinaryFile filename ReadMode countHandle h >>= print
import qualified Data.ByteString as B import qualified Data.ByteString.Char8 as B8 import System.IO import System.Environment countChar :: Char -> B.ByteString -> Integer countChar c = B8.foldl' (\acc c' -> if c' == c then acc + 1 else acc) 0 countHandle :: Handle -> IO Integer countHandle h = loop 0 where loop acc = do bytes <- B.hGet h 4096 if B.null bytes then return acc else let acc' = acc + countChar '\n' bytes in loop $! acc' main :: IO () main = do filename:_ <- getArgs h <- openBinaryFile filename ReadMode countHandle h >>= print
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