git.iko.soy/streamly
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streamly/examples/HandleIO.hs
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1import qualified Streamly.Prelude as S
2import qualified Streamly.Data.Fold as FL
3-- import qualified Streamly.Memory.Array as A
4import qualified Streamly.FileSystem.Handle as FH
5import qualified System.IO as FH
6-- import qualified Streamly.FileSystem.FD as FH
7-- import qualified Streamly.Data.Unicode.Stream as US
9import qualified Streamly.Internal.Data.Fold as FL
10import qualified Streamly.Internal.Memory.ArrayStream as AS
11import qualified Streamly.Internal.FileSystem.Handle as IFH
13import Data.Char (ord)
14import System.Environment (getArgs)
15import System.IO (IOMode(..), hSeek, SeekMode(..))
17cat :: FH.Handle -> IO ()
18cat src =
19 S.fold (FH.writeChunks FH.stdout)
20 $ IFH.toChunksWithBufferOf (256*1024) src
21-- byte stream version
22-- cat src = S.fold (FH.write FH.stdout) $ FH.read src
24cp :: FH.Handle -> FH.Handle -> IO ()
25cp src dst =
26 S.fold (FH.writeChunks dst)
27 $ IFH.toChunksWithBufferOf (256*1024) src
28-- byte stream version
29-- cp src dst = S.fold (FH.write dst) $ FH.read src
31ord' :: Num a => Char -> a
32ord' = (fromIntegral . ord)
34wcl :: FH.Handle -> IO ()
35wcl src = print =<< (S.length
36 $ AS.splitOn 10
37 $ IFH.toChunks src)
38{-
39-- Char stream version
40wcl src = print =<< (S.length
41 $ flip US.lines FL.drain
42 $ US.decodeLatin1
43 $ FH.read src)
44-}
46{-
47grepc :: String -> FH.Handle -> IO ()
48grepc pat src = print . (subtract 1) =<< (S.length
49 $ FL.splitOnSeq (A.fromList (map ord' pat)) FL.drain
50 $ FH.read src)
51-}
53avgll :: FH.Handle -> IO ()
54avgll src = print =<< (S.fold avg
55 $ S.splitWithSuffix (== ord' '\n') FL.length
56 $ S.unfold FH.read src)
57 where avg = (/) <$> toDouble FL.sum <*> toDouble FL.length
58 toDouble = fmap (fromIntegral :: Int -> Double)
60llhisto :: FH.Handle -> IO ()
61llhisto src = print =<< (S.fold (FL.classify FL.length)
62 $ S.map bucket
63 $ S.splitWithSuffix (== ord' '\n') FL.length
64 $ S.unfold FH.read src)
65 where
66 bucket n = let i = n `mod` 10 in if i > 9 then (9,n) else (i,n)
68main :: IO ()
69main = do
70 name <- fmap head getArgs
71 src <- FH.openFile name ReadMode
72 let rewind = hSeek src AbsoluteSeek 0
74 rewind >> putStrLn "cat" >> cat src -- Unix cat program
75 rewind >> putStr "wcl " >> wcl src -- Unix wc -l program
76 -- rewind >> putStr "grepc " >> grepc "aaaa" src -- Unix grep -c program
77 rewind >> putStr "avgll " >> avgll src -- get average line length
78 rewind >> putStr "llhisto " >> llhisto src -- get line length histogram
80 dst <- FH.openFile "dst-xyz.txt" WriteMode
81 rewind >> putStr "cp " >> cp src dst -- Unix cp program