module Data.CQRS.GUID
( GUID
, newGUID
) where
import Control.Monad (liftM)
import Data.ByteString (ByteString)
import qualified Data.ByteString as B
import Data.ByteString.Char8 ()
import Data.Default (Default(..))
import Data.Serialize (Serialize(..))
import Data.Typeable (Typeable)
import Data.Word (Word8)
import System.Random (randomRIO)
newtype GUID a = GUID ByteString
deriving (Show, Typeable, Eq)
instance Default (GUID a) where
def = GUID $ B.pack $ replicate 32 0
randomWord8 :: IO Word8
randomWord8 = fmap fromInteger $ randomRIO (0,255)
newGUID :: IO (GUID a)
newGUID = do
uuid <- sequence $ replicate 32 randomWord8
return $ GUID $ B.pack uuid
instance Serialize (GUID a) where
put (GUID s) = put s
get = liftM GUID get