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
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