module Network.Mail.Parse.Decoders.FormatDecoders (qpDec, decodeB64) where
import Foreign
import Foreign.C.Types
import System.IO.Unsafe as U
import qualified Data.ByteString as BS
import qualified Data.ByteString.Unsafe as BSU
import Data.ByteString.Unsafe
foreign import ccall "static qp.h qp_dec_c"
c_qp_dec :: Ptr Word8 -> CSize -> Ptr Word8 -> Ptr CSize -> Ptr (Ptr Word8) -> Ptr CSize -> IO CInt
foreign import ccall "static b64.h b64_dec_part_c"
c_b64_dec_part :: Ptr Word8 -> CSize -> Ptr Word8 -> Ptr CSize -> Ptr (Ptr Word8) -> Ptr CSize -> IO CInt
foreign import ccall "static b64.h b64_dec_final_c"
c_b64_dec_final :: Ptr Word8 -> CSize -> Ptr Word8 -> Ptr CSize -> IO CInt
castEnum :: (Enum a, Enum b) => a -> b
castEnum = toEnum . fromEnum
qpDec' :: BS.ByteString -> Either (BS.ByteString, BS.ByteString) (BS.ByteString, BS.ByteString)
qpDec' bs = U.unsafePerformIO $ BSU.unsafeUseAsCStringLen bs $ \ (inBuf, inLen) -> do
outBuf <- mallocBytes inLen
alloca $ \ pOutLen ->
alloca $ \ pRemBuf ->
alloca $ \ pRemLen -> do
poke pOutLen (castEnum inLen)
r <- c_qp_dec (castPtr inBuf) (castEnum inLen) outBuf pOutLen pRemBuf pRemLen
outLen <- peek pOutLen
newOutBuf <- reallocBytes outBuf (castEnum outLen)
remBuf <- peek pRemBuf
remLen <- peek pRemLen
remBs <- BS.packCStringLen (castPtr remBuf, castEnum remLen)
outBs <- BSU.unsafePackCStringFinalizer newOutBuf (castEnum outLen) (free newOutBuf)
if r == 0
then return $ Right (outBs, remBs)
else return $ Left (outBs, remBs)
qpDec :: BS.ByteString -> Either (BS.ByteString, BS.ByteString) BS.ByteString
qpDec bs = case qpDec' bs of
Right a@(d, r) -> if BS.null r
then Right d
else Left a
Left a -> Left a
b64DecodePart :: BS.ByteString -> Either (BS.ByteString, BS.ByteString) (BS.ByteString, BS.ByteString)
b64DecodePart bs = U.unsafePerformIO $ unsafeUseAsCStringLen bs $ \ (inBuf, inLen) -> do
let maxOutLen = inLen `div` 4 * 3
outBuf <- mallocBytes maxOutLen
alloca $ \ pOutLen ->
alloca $ \ pRemBuf ->
alloca $ \ pRemLen -> do
poke pOutLen (castEnum maxOutLen)
r <- c_b64_dec_part (castPtr inBuf) (castEnum inLen) outBuf pOutLen pRemBuf pRemLen
outLen <- peek pOutLen
newOutBuf <- reallocBytes outBuf (castEnum outLen)
remBuf <- peek pRemBuf
remLen <- peek pRemLen
remBs <- BS.packCStringLen (castPtr remBuf, castEnum remLen)
outBs <- unsafePackCStringFinalizer newOutBuf (castEnum outLen) (free newOutBuf)
if r == 0
then return $ Right (outBs, remBs)
else return $ Left (outBs, remBs)
b64DecodeFinal :: BS.ByteString -> Maybe BS.ByteString
b64DecodeFinal bs = U.unsafePerformIO $ unsafeUseAsCStringLen bs $ \ (inBuf, inLen) -> do
outBuf <- mallocBytes 3
alloca $ \ pOutLen -> do
r <- c_b64_dec_final (castPtr inBuf) (castEnum inLen) outBuf pOutLen
if r == 0
then do
outLen <- peek pOutLen
newOutBuf <- reallocBytes outBuf (castEnum outLen)
outBs <- unsafePackCStringFinalizer newOutBuf (castEnum outLen) (free newOutBuf)
return $ Just outBs
else free outBuf >> return Nothing
decodeB64 :: BS.ByteString -> Either (BS.ByteString, BS.ByteString) BS.ByteString
decodeB64 bs = either
Left
(\ (first, rest) ->
maybe
(Left (first, rest))
(\ fin -> Right (first `BS.append` fin))
(b64DecodeFinal rest))
(b64DecodePart bs)