module Data.Iteratee.IO.Handle(
enumHandle
,enumHandleRandom
,fileDriverHandle
,fileDriverRandomHandle
)
where
import Data.Iteratee.Base.StreamChunk (ReadableChunk (..))
import Data.Iteratee.Base
import Data.Iteratee.Binary()
import Data.Int
import Control.Exception.Extensible
import Foreign.Ptr
import Foreign.Marshal.Alloc
import System.IO
enumHandle :: ReadableChunk s el => Handle -> EnumeratorGM s el IO a
enumHandle h i = allocaBytes (fromIntegral buffer_size) $ loop i
where
buffer_size = 4096
loop iter p = do
n <- (try $ hGetBuf h p buffer_size) :: IO (Either SomeException Int)
case n of
Left _ -> enumErr "IO error" iter
Right 0 -> return iter
Right n' -> do
s <- readFromPtr p (fromIntegral n')
igv <- runIter iter (Chunk s)
check p igv
check _p (Done x _) = return . return $ x
check p (Cont i' Nothing) = loop i' p
check _p (Cont _ (Just e)) = return $ throwErr e
enumHandleRandom :: ReadableChunk s el => Handle -> EnumeratorGM s el IO a
enumHandleRandom h iter =
allocaBytes (fromIntegral buffer_size) (loop (0,0) iter)
where
buffer_size = 4096
loop (off,len) _iter' _p | off `seq` len `seq` False = undefined
loop (off,len) iter' p = do
n <- (try $ hGetBuf h p buffer_size) :: IO (Either SomeException Int)
case n of
Left _errno -> enumErr "IO error" iter
Right 0 -> return iter'
Right n' -> do
s <- readFromPtr p (fromIntegral n')
igv <- runIter iter' (Chunk s)
check (off + fromIntegral len,fromIntegral n') p igv
seekTo pos@(off, len) off' iter' p
| off <= off' && off' < off + fromIntegral len =
do
let local_off = fromIntegral $ off' off
s <- readFromPtr (p `plusPtr` local_off) (len local_off)
igv <- runIter iter' (Chunk s)
check pos p igv
seekTo _pos off iter' p = do
off' <- (try $ hSeek h AbsoluteSeek
(fromIntegral off)) :: IO (Either SomeException ())
case off' of
Left _errno -> enumErr "IO error" iter'
Right _ -> loop (off,0) iter' p
check _ _ (Done x _) = return . return $ x
check o p (Cont i Nothing) = loop o i p
check o p (Cont i (Just (Seek off))) = seekTo o off i p
check _ _ (Cont _ (Just e)) = return $ throwErr e
fileDriverHandle :: ReadableChunk s el =>
IterateeG s el IO a ->
FilePath ->
IO a
fileDriverHandle iter filepath = do
h <- openBinaryFile filepath ReadMode
result <- enumHandle h iter >>= run
hClose h
return result
fileDriverRandomHandle :: ReadableChunk s el =>
IterateeG s el IO a ->
FilePath ->
IO a
fileDriverRandomHandle iter filepath = do
h <- openBinaryFile filepath ReadMode
result <- enumHandleRandom h iter >>= run
hClose h
return result