module Data.Text.Internal.Encoding.Fusion
(
streamASCII
, streamUtf8
, streamUtf16LE
, streamUtf16BE
, streamUtf32LE
, streamUtf32BE
, unstream
, module Data.Text.Internal.Encoding.Fusion.Common
) where
#if defined(ASSERTS)
import Control.Exception (assert)
#endif
import Data.ByteString.Internal (ByteString(..), mallocByteString, memcpy)
import Data.Text.Internal.Fusion (Step(..), Stream(..))
import Data.Text.Internal.Fusion.Size
import Data.Text.Encoding.Error
import Data.Text.Internal.Encoding.Fusion.Common
import Data.Text.Internal.Unsafe.Char (unsafeChr, unsafeChr8, unsafeChr32)
import Data.Text.Internal.Unsafe.Shift (shiftL, shiftR)
import Data.Word (Word8, Word16, Word32)
import Foreign.ForeignPtr (withForeignPtr, ForeignPtr)
import Foreign.Storable (pokeByteOff)
import qualified Data.ByteString as B
import qualified Data.ByteString.Unsafe as B
import qualified Data.Text.Internal.Encoding.Utf8 as U8
import qualified Data.Text.Internal.Encoding.Utf16 as U16
import qualified Data.Text.Internal.Encoding.Utf32 as U32
import Data.Text.Unsafe (unsafeDupablePerformIO)
import Data.Text.Internal.ByteStringCompat
streamASCII :: ByteString -> Stream Char
streamASCII bs = Stream next 0 (maxSize l)
where
l = B.length bs
next i
| i >= l = Done
| otherwise = Yield (unsafeChr8 x1) (i+1)
where
x1 = B.unsafeIndex bs i
streamUtf8 :: OnDecodeError -> ByteString -> Stream Char
streamUtf8 onErr bs = Stream next 0 (maxSize l)
where
l = B.length bs
next i
| i >= l = Done
| U8.validate1 x1 = Yield (unsafeChr8 x1) (i+1)
| i+1 < l && U8.validate2 x1 x2 = Yield (U8.chr2 x1 x2) (i+2)
| i+2 < l && U8.validate3 x1 x2 x3 = Yield (U8.chr3 x1 x2 x3) (i+3)
| i+3 < l && U8.validate4 x1 x2 x3 x4 = Yield (U8.chr4 x1 x2 x3 x4) (i+4)
| otherwise = decodeError "streamUtf8" "UTF-8" onErr (Just x1) (i+1)
where
x1 = idx i
x2 = idx (i + 1)
x3 = idx (i + 2)
x4 = idx (i + 3)
idx = B.unsafeIndex bs
streamUtf16LE :: OnDecodeError -> ByteString -> Stream Char
streamUtf16LE onErr bs = Stream next 0 (maxSize (l `shiftR` 1))
where
l = B.length bs
next i
| i >= l = Done
| i+1 < l && U16.validate1 x1 = Yield (unsafeChr x1) (i+2)
| i+3 < l && U16.validate2 x1 x2 = Yield (U16.chr2 x1 x2) (i+4)
| otherwise = decodeError "streamUtf16LE" "UTF-16LE" onErr Nothing (i+1)
where
x1 = idx i + (idx (i + 1) `shiftL` 8)
x2 = idx (i + 2) + (idx (i + 3) `shiftL` 8)
idx = fromIntegral . B.unsafeIndex bs :: Int -> Word16
streamUtf16BE :: OnDecodeError -> ByteString -> Stream Char
streamUtf16BE onErr bs = Stream next 0 (maxSize (l `shiftR` 1))
where
l = B.length bs
next i
| i >= l = Done
| i+1 < l && U16.validate1 x1 = Yield (unsafeChr x1) (i+2)
| i+3 < l && U16.validate2 x1 x2 = Yield (U16.chr2 x1 x2) (i+4)
| otherwise = decodeError "streamUtf16BE" "UTF-16BE" onErr Nothing (i+1)
where
x1 = (idx i `shiftL` 8) + idx (i + 1)
x2 = (idx (i + 2) `shiftL` 8) + idx (i + 3)
idx = fromIntegral . B.unsafeIndex bs :: Int -> Word16
streamUtf32BE :: OnDecodeError -> ByteString -> Stream Char
streamUtf32BE onErr bs = Stream next 0 (maxSize (l `shiftR` 2))
where
l = B.length bs
next i
| i >= l = Done
| i+3 < l && U32.validate x = Yield (unsafeChr32 x) (i+4)
| otherwise = decodeError "streamUtf32BE" "UTF-32BE" onErr Nothing (i+1)
where
x = shiftL x1 24 + shiftL x2 16 + shiftL x3 8 + x4
x1 = idx i
x2 = idx (i+1)
x3 = idx (i+2)
x4 = idx (i+3)
idx = fromIntegral . B.unsafeIndex bs :: Int -> Word32
streamUtf32LE :: OnDecodeError -> ByteString -> Stream Char
streamUtf32LE onErr bs = Stream next 0 (maxSize (l `shiftR` 2))
where
l = B.length bs
next i
| i >= l = Done
| i+3 < l && U32.validate x = Yield (unsafeChr32 x) (i+4)
| otherwise = decodeError "streamUtf32LE" "UTF-32LE" onErr Nothing (i+1)
where
x = shiftL x4 24 + shiftL x3 16 + shiftL x2 8 + x1
x1 = idx i
x2 = idx $ i+1
x3 = idx $ i+2
x4 = idx $ i+3
idx = fromIntegral . B.unsafeIndex bs :: Int -> Word32
unstream :: Stream Word8 -> ByteString
unstream (Stream next s0 len) = unsafeDupablePerformIO $ do
let mlen = upperBound 4 len
mallocByteString mlen >>= loop mlen 0 s0
where
loop !n !off !s fp = case next s of
Done -> trimUp fp n off
Skip s' -> loop n off s' fp
Yield x s'
| off == n -> realloc fp n off s' x
| otherwise -> do
withForeignPtr fp $ \p -> pokeByteOff p off x
loop n (off+1) s' fp
realloc fp n off s x = do
let n' = n+n
fp' <- copy0 fp n n'
withForeignPtr fp' $ \p -> pokeByteOff p off x
loop n' (off+1) s fp'
trimUp fp _ off = return $! mkBS fp off
copy0 :: ForeignPtr Word8 -> Int -> Int -> IO (ForeignPtr Word8)
copy0 !src !srcLen !destLen =
#if defined(ASSERTS)
assert (srcLen <= destLen) $
#endif
do
dest <- mallocByteString destLen
withForeignPtr src $ \src' ->
withForeignPtr dest $ \dest' ->
memcpy dest' src' (fromIntegral srcLen)
return dest
decodeError :: forall s. String -> String -> OnDecodeError -> Maybe Word8
-> s -> Step s Char
decodeError func kind onErr mb i =
case onErr desc mb of
Nothing -> Skip i
Just c -> Yield c i
where desc = "Data.Text.Internal.Encoding.Fusion." ++ func ++ ": Invalid " ++
kind ++ " stream"