    -- |
    -- Module      : Crypto.Hash.Keccak
    -- License     : BSD-style
    -- Maintainer  : Vincent Hanquez <vincent@snarc.org>
    -- Stability   : experimental
    -- Portability : unknown
    --
    -- module containing the binding functions to work with the
    -- Keccak cryptographic hash.
    --
    {-# LANGUAGE ForeignFunctionInterface #-}
    module Crypto.Hash.Keccak
        (  Keccak_224 (..), Keccak_256 (..), Keccak_384 (..), Keccak_512 (..)
        ) where

    import           Crypto.Hash.Types
    import           Foreign.Ptr (Ptr)
    import           Data.Word (Word8, Word32)

    -- | Keccak (224 bits) cryptographic hash algorithm
    data Keccak_224 = Keccak_224
        deriving (Show)

    instance HashAlgorithm Keccak_224 where
        hashBlockSize  _          = 144
        hashDigestSize _          = 28
        hashInternalContextSize _ = 360
        hashInternalInit p        = c_keccak_init p 224
        hashInternalUpdate        = c_keccak_update
        hashInternalFinalize p    = c_keccak_finalize p 224

    -- | Keccak (256 bits) cryptographic hash algorithm
    data Keccak_256 = Keccak_256
        deriving (Show)

    instance HashAlgorithm Keccak_256 where
        hashBlockSize  _          = 136
        hashDigestSize _          = 32
        hashInternalContextSize _ = 360
        hashInternalInit p        = c_keccak_init p 256
        hashInternalUpdate        = c_keccak_update
        hashInternalFinalize p    = c_keccak_finalize p 256

    -- | Keccak (384 bits) cryptographic hash algorithm
    data Keccak_384 = Keccak_384
        deriving (Show)

    instance HashAlgorithm Keccak_384 where
        hashBlockSize  _          = 104
        hashDigestSize _          = 48
        hashInternalContextSize _ = 360
        hashInternalInit p        = c_keccak_init p 384
        hashInternalUpdate        = c_keccak_update
        hashInternalFinalize p    = c_keccak_finalize p 384

    -- | Keccak (512 bits) cryptographic hash algorithm
    data Keccak_512 = Keccak_512
        deriving (Show)

    instance HashAlgorithm Keccak_512 where
        hashBlockSize  _          = 72
        hashDigestSize _          = 64
        hashInternalContextSize _ = 360
        hashInternalInit p        = c_keccak_init p 512
        hashInternalUpdate        = c_keccak_update
        hashInternalFinalize p    = c_keccak_finalize p 512

    foreign import ccall unsafe "cryptonite_keccak_init"
        c_keccak_init :: Ptr (Context a) -> Word32 -> IO ()

    foreign import ccall "cryptonite_keccak_update"
        c_keccak_update :: Ptr (Context a) -> Ptr Word8 -> Word32 -> IO ()

    foreign import ccall unsafe "cryptonite_keccak_finalize"
        c_keccak_finalize :: Ptr (Context a) -> Word32 -> Ptr (Digest a) -> IO ()