module Data.CryptoHash.Skein256 (
Ctx(..),
init,
update,
finalize,
hash,
hashlazy
) where
import Prelude hiding (init)
import Foreign
import Foreign.C.String
import Foreign.C.Types
import qualified Data.ByteString as B
import qualified Data.ByteString.Lazy as L
import Data.ByteString (ByteString)
import Data.ByteString.Unsafe (unsafeUseAsCString, unsafeUseAsCStringLen)
import Data.ByteString.Internal (create, memcpy)
data Ctx = Ctx !ByteString
sizeCtx :: Int
sizeCtx = 100
instance Storable Ctx where
sizeOf _ = sizeCtx
alignment _ = 16
poke ptr (Ctx b) = unsafeUseAsCString b (\cs -> memcpy (castPtr ptr) (castPtr cs) (fromIntegral sizeCtx))
peek ptr = create sizeCtx (\bptr -> memcpy bptr (castPtr ptr) (fromIntegral sizeCtx)) >>= return . Ctx
poke_hashlen :: Ptr Ctx -> IO Int
poke_hashlen ptr = do
let iptr = castPtr ptr :: Ptr CUInt
a <- peek iptr
return $ fromIntegral a
foreign import ccall unsafe "skein256.h skein256_init"
c_skein256_init :: Ptr Ctx -> CUInt -> IO ()
foreign import ccall "skein256.h skein256_update"
c_skein256_update :: Ptr Ctx -> CString -> Word32 -> IO ()
foreign import ccall unsafe "skein256.h skein256_finalize"
c_skein256_finalize :: Ptr Ctx -> CString -> IO ()
allocInternal :: (Ptr Ctx -> IO a) -> IO a
allocInternal = alloca
allocInternalFrom :: Ctx -> (Ptr Ctx -> IO a) -> IO a
allocInternalFrom ctx f = allocInternal $ \ptr -> (poke ptr ctx >> f ptr)
updateInternalIO :: Ptr Ctx -> ByteString -> IO ()
updateInternalIO ptr d =
unsafeUseAsCStringLen d (\(cs, len) -> c_skein256_update ptr cs (fromIntegral len))
finalizeInternalIO :: Ptr Ctx -> IO ByteString
finalizeInternalIO ptr = do
digestSize <- fmap (\x -> (x + 7) `shiftR` 3) $ poke_hashlen ptr
allocaBytes digestSize (\cs -> c_skein256_finalize ptr cs >> B.packCStringLen (cs, digestSize))
init :: Int -> Ctx
init hashlen = unsafePerformIO $ allocInternal $ \ptr -> do (c_skein256_init ptr (fromIntegral hashlen) >> peek ptr)
update :: Ctx -> ByteString -> Ctx
update ctx d = unsafePerformIO $ allocInternalFrom ctx $ \ptr -> do updateInternalIO ptr d >> peek ptr
finalize :: Ctx -> ByteString
finalize ctx = unsafePerformIO $ allocInternalFrom ctx $ \ptr -> do finalizeInternalIO ptr
hash :: Int -> ByteString -> ByteString
hash hashlen d = unsafePerformIO $ allocInternal $ \ptr -> do
c_skein256_init ptr (fromIntegral hashlen) >> updateInternalIO ptr d >> finalizeInternalIO ptr
hashlazy :: Int -> L.ByteString -> ByteString
hashlazy hashlen l = unsafePerformIO $ allocInternal $ \ptr -> do
c_skein256_init ptr (fromIntegral hashlen) >> mapM_ (updateInternalIO ptr) (L.toChunks l) >> finalizeInternalIO ptr