-- | Entropy based on `/dev/urandom`.
module Entropy( getEntropy, entropySource ) where

import System.IO
import Raaz.Core



-- | The name of the source from which entropy is gathered. For
-- information purposes only.
entropySource :: String
entropySource = "/dev/urandom(generic posix)"

-- | Get random bytes from the system. Do not over use this function
-- as it is meant to be used by a PRG. This function reads bytes from
-- '/dev/urandom'.
getEntropy ::  BYTES Int -> Ptr Word8 -> IO (BYTES Int)
getEntropy l ptr = withBinaryFile "/dev/urandom" ReadMode
                   $ \ hand -> hFillBuf hand ptr l