Yitzchak Gale wrote:
It's short, so I'll post it here. Any comments?
readDev :: Storable a => FilePath -> BlockingMode -> IO (Maybe a) readDev dev mode = do h <- openFile dev ReadMode hSetBuffering h NoBuffering alloca $ getMaybe h undefined where getMaybe :: Storable a => Handle -> a -> Ptr a -> IO (Maybe a) getMaybe h undef ptr = do let size = sizeOf undef n <- case mode of Blocking -> hGetBuf h ptr size NonBlocking -> hGetBufNonBlocking h ptr size if n < size then return Nothing else peek ptr >>= return . Just
This re-opens the device every time we need it. How about opening once, when it's first needed? hDevRandom :: Handle {-# NOINLINE hDevRandom #-} hDevRandom = unsafePerformIO $ openFile "/dev/random" ReadMode hDevURandom :: Handle {-# NOINLINE hDevURandom #-} hDevURandom = unsafePerformIO $ openFile "/dev/urandom" ReadMode