git.iko.soy/streamly
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Fix a performance issue with File.read
fc6d77aHarendra Kumar
examples/FileIO.hsnew file+52
compare with master
unifiedsplit
@@ -0,0 +1,52 @@
1+import qualified Streamly.Prelude as S
2+import qualified Streamly.Fold as FL
3+import qualified Streamly.Mem.Array as A
4+import qualified Streamly.FileSystem.File as File
5+
6+import Data.Char (ord)
7+import System.Environment (getArgs)
8+
9+cat :: FilePath -> IO ()
10+cat src = File.writeArrays "/dev/stdout" $ File.readArraysUpto (256*1024) src
11+
12+cp :: FilePath -> FilePath -> IO ()
13+cp src dst = File.writeArrays dst $ File.readArraysUpto (256*1024) src
14+
15+ord' :: Num a => Char -> a
16+ord' = (fromIntegral . ord)
17+
18+wcl :: FilePath -> IO ()
19+wcl src = print =<< (S.length
20+ $ FL.splitSuffixBy (== ord' '\n') FL.drain
21+ $ File.read src)
22+
23+grepc :: String -> FilePath -> IO ()
24+grepc pat src = print . (subtract 1) =<< (S.length
25+ $ FL.splitOn (A.fromList (map ord' pat)) FL.drain
26+ $ File.read src)
27+
28+avgll :: FilePath -> IO ()
29+avgll src = print =<< (FL.foldl' avg
30+ $ FL.splitSuffixBy (== ord' '\n') FL.length
31+ $ File.read src)
32+ where avg = (/) <$> toDouble FL.sum <*> toDouble FL.length
33+ toDouble = fmap (fromIntegral :: Int -> Double)
34+
35+llhisto :: FilePath -> IO ()
36+llhisto src = print =<< (FL.foldl' (FL.classify FL.length)
37+ $ S.map bucket
38+ $ FL.splitSuffixBy (== ord' '\n') FL.length
39+ $ File.read src)
40+ where
41+ bucket n = let i = n `div` 10 in if i > 9 then (9,n) else (i,n)
42+
43+main :: IO ()
44+main = do
45+ src <- fmap head getArgs
46+
47+ putStrLn "cat" >> cat src -- Unix cat program
48+ putStr "wcl " >> wcl src -- Unix wc -l program
49+ putStr "grepc " >> grepc "aaaa" src -- Unix grep -c program
50+ putStr "avgll " >> avgll src -- get average line length
51+ putStr "llhisto " >> llhisto src -- get line length histogram
52+ putStr "cp " >> cp src "dst-xyz.txt" -- Unix cp program
src/Streamly/FileSystem/File.hs+2−1
@@ -150,6 +150,7 @@ import qualified Streamly.Prelude as S
150-- raising an exception. If closing the handle raises an exception, then
150-- raising an exception. If closing the handle raises an exception, then
151-- this exception will be raised by 'withFile' rather than any exception
151-- this exception will be raised by 'withFile' rather than any exception
152-- raised by 'act'.
152-- raised by 'act'.
153+{-# INLINE withFile #-}
153withFile :: (IsStream t, MonadCatch m, MonadIO m)
154withFile :: (IsStream t, MonadCatch m, MonadIO m)
154 => FilePath -> IOMode -> (Handle -> t m a) -> t m a
155 => FilePath -> IOMode -> (Handle -> t m a) -> t m a
155withFile file mode = S.bracket (liftIO $ openFile file mode) (liftIO . hClose)
156withFile file mode = S.bracket (liftIO $ openFile file mode) (liftIO . hClose)
@@ -232,7 +233,7 @@ readByChunksUpto chunkSize h = A.flattenArrays $ readArraysUpto chunkSize h
232-- @since 0.7.0
233-- @since 0.7.0
233{-# INLINE read #-}
234{-# INLINE read #-}
234read :: (IsStream t, MonadCatch m, MonadIO m) => FilePath -> t m Word8
235read :: (IsStream t, MonadCatch m, MonadIO m) => FilePath -> t m Word8
235−read file = withFile file ReadMode FH.read
236+read file = A.flattenArrays $ withFile file ReadMode FH.readArrays
236
237
237{-
238{-
238-- | Generate a stream of elements of the given type from a file 'Handle'. The
239-- | Generate a stream of elements of the given type from a file 'Handle'. The
streamly.cabal+13
@@ -944,3 +944,16 @@ executable HandleIO
944 , base >= 4.8 && < 5
944 , base >= 4.8 && < 5
945 else
945 else
946 buildable: False
946 buildable: False
947+
948+executable FileIO
949+ default-language: Haskell2010
950+ main-is: FileIO.hs
951+ hs-source-dirs: examples
952+ ghc-options: -Wall
953+ if flag(examples) || flag(examples-sdl)
954+ buildable: True
955+ build-Depends:
956+ streamly
957+ , base >= 4.8 && < 5
958+ else
959+ buildable: False