module Crypto.Random.Entropy.Backend
( EntropyBackend
, supportedBackends
, gatherBackend
) where
import Foreign.Ptr
import Data.Word (Word8)
import Crypto.Random.Entropy.Source
#ifdef SUPPORT_RDRAND
import Crypto.Random.Entropy.RDRand
#endif
#ifdef WINDOWS
import Crypto.Random.Entropy.Windows
#else
import Crypto.Random.Entropy.Unix
#endif
supportedBackends :: [IO (Maybe EntropyBackend)]
supportedBackends =
[
#ifdef SUPPORT_RDRAND
openBackend (undefined :: RDRand),
#endif
#ifdef WINDOWS
openBackend (undefined :: WinCryptoAPI)
#else
openBackend (undefined :: DevRandom), openBackend (undefined :: DevURandom)
#endif
]
data EntropyBackend = forall b . EntropySource b => EntropyBackend b
openBackend :: EntropySource b => b -> IO (Maybe EntropyBackend)
openBackend b = fmap EntropyBackend `fmap` callOpen b
where callOpen :: EntropySource b => b -> IO (Maybe b)
callOpen _ = entropyOpen
gatherBackend :: EntropyBackend
-> Ptr Word8
-> Int
-> IO Int
gatherBackend (EntropyBackend backend) ptr n = entropyGather backend ptr n