71 lines
2.8 KiB
Haskell
71 lines
2.8 KiB
Haskell
-- |
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-- Module : Crypto.Hash.IO
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-- License : BSD-style
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-- Maintainer : Vincent Hanquez <vincent@snarc.org>
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-- Stability : experimental
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-- Portability : unknown
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--
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-- Generalized impure cryptographic hash interface
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--
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{-# LANGUAGE GeneralizedNewtypeDeriving #-}
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{-# LANGUAGE ScopedTypeVariables #-}
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module Crypto.Hash.IO
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( HashAlgorithm(..)
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, MutableContext
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, hashMutableInit
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, hashMutableInitWith
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, hashMutableUpdate
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, hashMutableFinalize
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, hashMutableReset
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) where
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import Crypto.Hash.Types
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import qualified Crypto.Internal.ByteArray as B
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import Foreign.Ptr
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-- | A Mutable hash context
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--
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-- This type is an instance of 'B.ByteArrayAccess' for debugging purpose.
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-- Internal layout is architecture dependent, may contain uninitialized data
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-- fragments, and change in future versions. The bytearray should not be used
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-- as input to cryptographic algorithms.
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newtype MutableContext a = MutableContext B.Bytes
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deriving (B.ByteArrayAccess)
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-- | Create a new mutable hash context.
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--
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-- the algorithm used is automatically determined from the return constraint.
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hashMutableInit :: HashAlgorithm alg => IO (MutableContext alg)
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hashMutableInit = doInit undefined B.alloc
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where
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doInit :: HashAlgorithm a => a -> (Int -> (Ptr (Context a) -> IO ()) -> IO B.Bytes) -> IO (MutableContext a)
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doInit alg alloc = MutableContext `fmap` alloc (hashInternalContextSize alg) hashInternalInit
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-- | Create a new mutable hash context.
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--
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-- The algorithm is explicitely passed as parameter
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hashMutableInitWith :: HashAlgorithm alg => alg -> IO (MutableContext alg)
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hashMutableInitWith _ = hashMutableInit
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-- | Update a mutable hash context in place
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hashMutableUpdate :: (B.ByteArrayAccess ba, HashAlgorithm a) => MutableContext a -> ba -> IO ()
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hashMutableUpdate mc dat = doUpdate mc (B.withByteArray mc)
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where doUpdate :: HashAlgorithm a => MutableContext a -> ((Ptr (Context a) -> IO ()) -> IO ()) -> IO ()
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doUpdate _ withCtx =
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withCtx $ \ctx ->
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B.withByteArray dat $ \d ->
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hashInternalUpdate ctx d (fromIntegral $ B.length dat)
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-- | Finalize a mutable hash context and compute a digest
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hashMutableFinalize :: forall a . HashAlgorithm a => MutableContext a -> IO (Digest a)
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hashMutableFinalize mc = do
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b <- B.alloc (hashDigestSize (undefined :: a)) $ \dig -> B.withByteArray mc $ \(ctx :: Ptr (Context a)) -> hashInternalFinalize ctx dig
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return $ Digest b
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-- | Reset the mutable context to the initial state of the hash
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hashMutableReset :: HashAlgorithm a => MutableContext a -> IO ()
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hashMutableReset mc = doReset mc (B.withByteArray mc)
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where
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doReset :: HashAlgorithm a => MutableContext a -> ((Ptr (Context a) -> IO ()) -> IO ()) -> IO ()
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doReset _ withCtx = withCtx hashInternalInit
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