{-# LANGUAGE CPP, ForeignFunctionInterface #-} #if defined(__GLASGOW_HASKELL__) && __GLASGOW_HASKELL__ >= 702 {-# LANGUAGE Trustworthy #-} #endif module Data.Hashable.RandomSource ( getRandomBytes , getRandomBytes_ ) where import Data.ByteString as B import Data.ByteString.Internal (create) import Foreign.C.Error (throwErrnoIfMinus1_) #if MIN_VERSION_base(4,5,0) import Foreign.C.Types (CInt(CInt)) #else import Foreign.C.Types (CInt) #endif import Foreign.Ptr (Ptr) getRandomBytes :: Int -> IO ByteString getRandomBytes nbytes | nbytes <= 0 = return B.empty | otherwise = create nbytes $ flip (getRandomBytes_ "getRandomBytes") nbytes getRandomBytes_ :: String -> Ptr a -> Int -> IO () getRandomBytes_ what ptr nbytes = do throwErrnoIfMinus1_ what $ c_getRandomBytes ptr (fromIntegral nbytes) foreign import ccall unsafe "hashable_getRandomBytes" c_getRandomBytes :: Ptr a -> CInt -> IO CInt