{-# LANGUAGE CApiFFI #-}

{-# LANGUAGE Unsafe  #-}

-- Ugly hack to workaround https://ghc.haskell.org/trac/ghc/ticket/14452

{-# OPTIONS_GHC -O0

                -fdo-lambda-eta-expansion

                -fcase-merge

                -fstrictness

                -fno-omit-interface-pragmas

                -fno-ignore-interface-pragmas #-}

{-# OPTIONS_GHC -optc-Wall -optc-O3 #-}

-- |

-- Module      : Crypto.Hash.SHA256.FFI

-- License     : BSD-3

-- Maintainer  : Herbert Valerio Riedel <hvr@gnu.org>

--

module Crypto.Hash.SHA256.FFI where

import           Data.ByteString (ByteString)

import           Data.Word

import           Foreign.C.Types

import           Foreign.Ptr

-- | SHA-256 Context

--

-- The context data is exactly 104 bytes long, however

-- the data in the context is stored in host-endianness.

--

-- The context data is made up of

--

--  * a 'Word64' representing the number of bytes already feed to hash algorithm so far,

--

--  * a 64-element 'Word8' buffer holding partial input-chunks, and finally

--

--  * a 8-element 'Word32' array holding the current work-in-progress digest-value.

--

-- Consequently, a SHA-256 digest as produced by 'hash', 'hashlazy', or 'finalize' is 32 bytes long.

newtype Ctx = Ctx ByteString

foreign import capi unsafe "hs_sha256.h hs_cryptohash_sha256_init"

    c_sha256_init :: Ptr Ctx -> IO ()

foreign import capi unsafe "hs_sha256.h hs_cryptohash_sha256_update"

    c_sha256_update_unsafe :: Ptr Ctx -> Ptr Word8 -> CSize -> IO ()

foreign import capi safe "hs_sha256.h hs_cryptohash_sha256_update"

    c_sha256_update_safe :: Ptr Ctx -> Ptr Word8 -> CSize -> IO ()

foreign import capi unsafe "hs_sha256.h hs_cryptohash_sha256_finalize"

    c_sha256_finalize_len :: Ptr Ctx -> Ptr Word8 -> IO Word64

foreign import capi unsafe "hs_sha256.h hs_cryptohash_sha256_finalize"

    c_sha256_finalize :: Ptr Ctx -> Ptr Word8 -> IO ()

foreign import capi unsafe "hs_sha256.h hs_cryptohash_sha256_hash"

    c_sha256_hash_unsafe :: Ptr Word8 -> CSize -> Ptr Word8 -> IO ()

foreign import capi safe "hs_sha256.h hs_cryptohash_sha256_hash"

    c_sha256_hash_safe :: Ptr Word8 -> CSize -> Ptr Word8 -> IO ()