content: {-# LANGUAGE CPP #-}
  {-# LANGUAGE ForeignFunctionInterface #-}
  {-# LANGUAGE MagicHash                #-}
  {-# LANGUAGE UnliftedFFITypes         #-}
  {-# LANGUAGE BangPatterns         #-}
  {-# LANGUAGE MultiWayIf         #-}
  
  {-# OPTIONS_GHC -Wno-unused-imports #-}
  
  module Data.JsonStream.Unescape (
      unescapeText
    , unsafeDecodeASCII
  ) where
  
  import           Data.ByteString            as B
  import           Data.ByteString.Internal   as B hiding (c2w)
  import           Data.Text.Encoding.Error   (UnicodeException (..))
  import           Data.Text.Internal         (Text (..))
  import           Data.Text.Unsafe           (unsafeDupablePerformIO)
  import           Data.Word                  (Word8, Word32)
  import           Foreign.ForeignPtr         (withForeignPtr)
  import           Foreign.Ptr                (Ptr, plusPtr)
  import           Foreign.Storable           (peek)
  import qualified Data.Text as T
  
  #if MIN_VERSION_text(2,0,0)
  
  import qualified Data.Primitive           as P
  import qualified Data.Text.Array          as TA
  import qualified Data.Text.Internal       as T
  import           Data.Bits                (shiftL, shiftR, (.&.), (.|.))
  import           Control.Exception        (try, throwIO)
  import Foreign.ForeignPtr (ForeignPtr)
  import qualified Data.ByteString.Short.Internal as SBS
  
  #else
  
  import           Control.Exception          (evaluate, throw, try)
  import           Control.Monad.ST.Unsafe    (unsafeIOToST, unsafeSTToIO)
  import           Data.Text.Internal.Private (runText)
  import           Foreign.Marshal.Utils      (with)
  import qualified Data.Text.Array            as A
  import           GHC.Base                   (MutableByteArray#)
  import           Foreign.C.Types            (CInt (..), CSize (..))
  import qualified Data.Text.Encoding as TE
  
  #endif
  
  unsafeDecodeASCII :: ByteString -> T.Text
  
  #if MIN_VERSION_text(2,0,0)
  unsafeDecodeASCII bs = withBS bs $ \_fp len -> if len == 0 then T.empty else
    let !(SBS.SBS arr) = SBS.toShort bs in T.Text (TA.ByteArray arr) 0 len
  
  #else
  unsafeDecodeASCII = TE.decodeLatin1
  #endif
  
  
  #if !MIN_VERSION_text(2,0,0)
  
  foreign import ccall unsafe "_jstream_decode_string" c_js_decode
      :: MutableByteArray# s -> Ptr CSize
      -> Ptr Word8 -> Ptr Word8 -> IO CInt
  
  unescapeText' :: ByteString -> Text
  unescapeText' (PS fp off len) = runText $ \done -> do
    let go dest = withForeignPtr fp $ \ptr ->
          with (0::CSize) $ \destOffPtr -> do
            let end = ptr `plusPtr` (off + len)
                loop curPtr = do
                  res <- c_js_decode (A.maBA dest) destOffPtr curPtr end
                  case res of
                    0 -> do
                      n <- peek destOffPtr
                      unsafeSTToIO (done dest (fromIntegral n))
                    _ ->
                      throw (DecodeError desc Nothing)
            loop (ptr `plusPtr` off)
    (unsafeIOToST . go) =<< A.new len
   where
    desc = "Data.JsonStream.Unescape.unescapeText': Invalid UTF-8 stream"
  {-# INLINE unescapeText' #-}
  
  unescapeText :: ByteString -> Either UnicodeException Text
  unescapeText = unsafeDupablePerformIO . try . evaluate . unescapeText'
  {-# INLINE unescapeText #-}
  
  #else
  
  withBS :: ByteString -> (ForeignPtr Word8 -> Int -> r) -> r
  #if MIN_VERSION_bytestring(0,11,0)
  withBS (BS !sfp !slen)       kont = kont sfp slen
  #else
  withBS (PS !sfp !soff !slen) kont = kont (plusForeignPtr sfp soff) slen
  #endif
  {-# INLINE withBS #-}
  
  unescapeText :: ByteString -> Either UnicodeException Text
  unescapeText = unsafeDupablePerformIO . try . unescapeTextIO
  
  throwDecodeError :: IO a
  throwDecodeError =
    let desc = "Data.Text.Internal.Encoding.decodeUtf8: Invalid UTF-8 stream"
     in throwIO (DecodeError desc Nothing)
  
  -- The following is copied from aeson-2.0 
  
  -------------------------------------------------------------------------------
  -- unescapeTextIO
  -------------------------------------------------------------------------------
  
  -- This function is generated using staged-streams
  -- See: https://github.com/phadej/staged/blob/master/staged-streams-unicode/src/Unicode/JSON.hs
  --
  -- Because @aeson@ better to not use template-haskell itself,
  -- we dump the splice and prettify it by hand a bit.
  --
  unescapeTextIO :: ByteString -> IO Text
  unescapeTextIO bs = withBS bs $ \fptr len ->
    withForeignPtr fptr $ \begin -> do
      let end :: Ptr Word8
          end = plusPtr begin len
  
      arr <- P.newPrimArray len
  
      let write3bytes :: Int -> Word8 -> Word8 -> Word8 -> Ptr Word8 -> IO Text
          write3bytes !out !b1 !b2 !b3 !inp = do
            P.writePrimArray arr out b1
            write2bytes (out + 1) b2 b3 inp
  
          write2bytes :: Int -> Word8 -> Word8 -> Ptr Word8 -> IO Text
          write2bytes !out !b1 !b2 !inp = do
            P.writePrimArray arr out b1
            write1byte (out + 1) b2 inp
  
          write1byte :: Int -> Word8 -> Ptr Word8 -> IO Text
          write1byte !out !b1 !inp = do
            P.writePrimArray arr out b1
            state_start (out + 1) inp
  
          writeCodePoint :: Int -> Ptr Word8 -> Word32 -> IO Text
          writeCodePoint !out !inp !acc
            | acc <= 127 = do
              P.writePrimArray arr out (fromIntegral acc :: Word8)
              state_start (out + 1) (plusPtr inp 1)
  
            | acc <= 2047 = do
              let b1 = fromIntegral (shiftR acc 6 .|. 192) :: Word8
              let b2 = fromIntegral ((acc .&. 63) .|. 128) :: Word8
              P.writePrimArray arr out b1
              write1byte (out + 1) b2 (plusPtr inp 1)
  
            | acc <= 65535 = do
              let b1 = fromIntegral (shiftR acc 12 .|. 224) :: Word8
              let b2 = fromIntegral ((shiftR acc 6 .&. 63) .|.  128) :: Word8
              let b3 = fromIntegral ((acc .&. 63) .|. 128) :: Word8
              P.writePrimArray arr out b1
              write2bytes (out + 1) b2 b3 (plusPtr inp 1)
  
            | otherwise = do
              let b1 = fromIntegral (shiftR acc 18 .|. 240) :: Word8
              let b2 = fromIntegral ((shiftR acc 12 .&. 63) .|. 128) :: Word8
              let b3 = fromIntegral ((shiftR acc 6 .&. 63) .|. 128) :: Word8
              let b4 = fromIntegral ((acc .&. 63) .|. 128) :: Word8
              P.writePrimArray arr out b1
              write3bytes (out + 1) b2 b3 b4 (plusPtr inp 1)
  
          state_sudone :: Int -> Ptr Word8 -> Word32 -> Word32 -> IO Text
          state_sudone !out !inp !hi !lo
            | 56320 <= lo, lo <= 57343
            = writeCodePoint out inp (65536 + (shiftL (hi - 55296) 10 .|.  (lo - 56320)))
            
            | otherwise
            = throwDecodeError
  
          state_su4 :: Int -> Ptr Word8 -> Word32 -> Word32 -> IO Text
          state_su4 !out !inp !hi !acc
            | inp == end = throwDecodeError
            | otherwise = do
              w8 <- peek inp
              if | 48 <= w8, w8 <= 57 ->
                   state_sudone out inp hi (shiftL acc 4 .|. fromIntegral (w8 - 48))
                 | 65 <= w8, w8 <= 70 ->
                   state_sudone out inp hi (shiftL acc 4 .|. fromIntegral (w8 - 55))
                 | 97 <= w8, w8 <= 102 ->
                   state_sudone out inp hi (shiftL acc 4 .|. fromIntegral (w8 - 87))
                 | otherwise ->
                   throwDecodeError
  
          state_su3 :: Int -> Ptr Word8 -> Word32 -> Word32 -> IO Text
          state_su3 !out !inp !hi !acc
            | inp == end = throwDecodeError
            | otherwise = do
              w8 <- peek inp
              if | 48 <= w8, w8 <= 57 ->
                   state_su4 out (plusPtr inp 1) hi (shiftL acc 4 .|. fromIntegral (w8 - 48))
                 | 65 <= w8, w8 <= 70 ->
                   state_su4 out (plusPtr inp 1) hi (shiftL acc 4 .|. fromIntegral (w8 - 55))
                 | 97 <= w8, w8 <= 102 ->
                   state_su4 out (plusPtr inp 1) hi (shiftL acc 4 .|. fromIntegral (w8 - 87))
                 | otherwise ->
                   throwDecodeError
  
          state_su2 :: Int -> Ptr Word8 -> Word32 -> Word32 -> IO Text
          state_su2 !out !inp !hi !acc
            | inp == end = throwDecodeError
            | otherwise = do
              w8 <- peek inp
              if | 48 <= w8, w8 <= 57 -> 
                   state_su3 out (plusPtr inp 1) hi (shiftL acc 4 .|. fromIntegral (w8 - 48))
                 | 65 <= w8, w8 <= 70 ->
                   state_su3 out (plusPtr inp 1) hi (shiftL acc 4 .|. fromIntegral (w8 - 55))
                 | 97 <= w8, w8 <= 102 ->
                   state_su3 out (plusPtr inp 1) hi (shiftL acc 4 .|. fromIntegral (w8 - 87))
                 | otherwise ->
                   throwDecodeError
  
          state_su1 :: Int -> Ptr Word8 -> Word32 -> IO Text
          state_su1 !out !inp !hi
            | inp == end = throwDecodeError
            | otherwise = do
              w8 <- peek inp
              if | 48 <= w8, w8 <= 57 ->
                   state_su2 out (plusPtr inp 1) hi (fromIntegral (w8 - 48))
                 | 65 <= w8, w8 <= 70 ->
                   state_su2 out (plusPtr inp 1) hi (fromIntegral (w8 - 55))
                 | 97 <= w8, w8 <= 102 ->
                   state_su2 out (plusPtr inp 1) hi (fromIntegral (w8 - 87))
                 | otherwise ->
                   throwDecodeError
  
          state_su :: Int -> Ptr Word8 -> Word32 -> IO Text
          state_su !out !inp !hi
            | inp == end = throwDecodeError
            | otherwise = do
              w8 <- peek inp
              case w8 of
                117 -> state_su1 out (plusPtr inp 1) hi
                _   -> throwDecodeError
  
          state_ss :: Int -> Ptr Word8 -> Word32 -> IO Text
          state_ss !out !inp !hi
            | inp == end = throwDecodeError
            | otherwise = do
              w8 <- peek inp
              case w8 of
                92 -> state_su out (plusPtr inp 1) hi
                _  -> throwDecodeError
  
          state_udone :: Int -> Ptr Word8 -> Word32 -> IO Text
          state_udone !out !inp !acc
            | acc < 55296 || acc > 57343 =
              writeCodePoint out inp acc
  
            | acc < 56320 =
              state_ss out (plusPtr inp 1) acc
  
            | otherwise =
              throwDecodeError
  
          state_u4 :: Int -> Ptr Word8 -> Word32 -> IO Text
          state_u4 !out !inp !acc
            | inp == end = throwDecodeError
            | otherwise = do
              w8 <- peek inp
              if | 48 <= w8, w8 <= 57 ->
                   state_udone out inp (shiftL acc 4 .|. fromIntegral (w8 - 48))
                 | 65 <= w8, w8 <= 70 ->
                   state_udone out inp (shiftL acc 4 .|. fromIntegral (w8 - 55))
                 | 97 <= w8, w8 <= 102 ->
                   state_udone out inp (shiftL acc 4 .|. fromIntegral (w8 - 87))
                 | otherwise ->
                   throwDecodeError
  
          state_u3 :: Int -> Ptr Word8 -> Word32 -> IO Text
          state_u3 !out !inp !acc
            | inp == end = throwDecodeError
            | otherwise = do
              w8 <- peek inp
              if | 48 <= w8, w8 <= 57 ->
                   state_u4 out (plusPtr inp 1) (shiftL acc 4 .|. fromIntegral (w8 - 48))
                 | 65 <= w8, w8 <= 70 ->
                   state_u4 out (plusPtr inp 1) (shiftL acc 4 .|. fromIntegral (w8 - 55))
                 | 97 <= w8, w8 <= 102 ->
                   state_u4 out (plusPtr inp 1) (shiftL acc 4 .|. fromIntegral (w8 - 87))
                 | otherwise ->
                   throwDecodeError
  
          state_u2 :: Int -> Ptr Word8 -> Word32 -> IO Text
          state_u2 !out !inp !acc
            | inp == end = throwDecodeError
            | otherwise = do
              w8 <- peek inp
              if | 48 <= w8, w8 <= 57 ->
                   state_u3 out (plusPtr inp 1) (shiftL acc 4 .|. fromIntegral (w8 - 48))
                 | 65 <= w8, w8 <= 70 ->
                   state_u3 out (plusPtr inp 1) (shiftL acc 4 .|. fromIntegral (w8 - 55))
                 | 97 <= w8, w8 <= 102 ->
                   state_u3 out (plusPtr inp 1) (shiftL acc 4 .|. fromIntegral (w8 - 87))
                 | otherwise ->
                   throwDecodeError
  
          state_u1 :: Int -> Ptr Word8 -> IO Text
          state_u1 !out !inp
            | inp == end = throwDecodeError
            | otherwise = do
              w8 <- peek inp
              if | 48 <= w8, w8 <= 57 ->
                   state_u2 out (plusPtr inp 1) (fromIntegral (w8 - 48))
                 | 65 <= w8, w8 <= 70 ->
                   state_u2 out (plusPtr inp 1) (fromIntegral (w8 - 55))
                 | 97 <= w8, w8 <= 102 ->
                   state_u2 out (plusPtr inp 1) (fromIntegral (w8 - 87))
                 | otherwise ->
                   throwDecodeError
  
          state_escape :: Int -> Ptr Word8 -> IO Text
          state_escape !out !inp
            | inp == end = throwDecodeError
            | otherwise  = do
              w8 <- peek inp
              case w8 of
                34 -> do
                  P.writePrimArray arr out 34
                  state_start (out + 1) (plusPtr inp 1)
  
                92 -> do
                  P.writePrimArray arr out 92
                  state_start (out + 1) (plusPtr inp 1)
  
                47 -> do
                  P.writePrimArray arr out 47
                  state_start (out + 1) (plusPtr inp 1)
  
                98 -> do
                  P.writePrimArray arr out 8
                  state_start (out + 1) (plusPtr inp 1)
  
                102 -> do
                  P.writePrimArray arr out 12
                  state_start (out + 1) (plusPtr inp 1)
  
                110 -> do
                  P.writePrimArray arr out 10
                  state_start (out + 1) (plusPtr inp 1)
  
                114 -> do
                  P.writePrimArray arr out 13
                  state_start (out + 1) (plusPtr inp 1)
  
                116 -> do
                  P.writePrimArray arr out 9
                  state_start (out + 1) (plusPtr inp 1)
  
                117 ->
                  state_u1 out (plusPtr inp 1)
  
                _ -> throwDecodeError
  
          state_input4c :: Int -> Ptr Word8 -> Word8 -> Word8 -> Word8 -> IO Text
          state_input4c !out !inp !b1 !b2 !b3
            | inp == end = throwDecodeError
            | otherwise  = do
              w8 <- peek inp
              if | (w8 .&. 192) == 128
                 , let acc    = shiftL (fromIntegral (b1 .&. 7)) 18
                 , let acc'   = acc .|. shiftL (fromIntegral (b2 .&. 63)) 12
                 , let acc''  = acc' .|. shiftL (fromIntegral (b3 .&. 63)) 6
                 , let acc''' = acc'' .|. fromIntegral (w8 .&. 63) :: Word32
                 , acc''' >= 65536 && acc''' < 1114112 -> do
                   P.writePrimArray arr out b1
                   write3bytes (out + 1) b2 b3 w8 (plusPtr inp 1)
  
                 | otherwise ->
                   throwDecodeError
  
          state_input4b :: Int -> Ptr Word8 -> Word8 -> Word8 -> IO Text
          state_input4b !out !inp !b1 !b2
            | inp == end = throwDecodeError
            | otherwise  = do
              w8 <- peek inp
              if | (w8 .&. 192) == 128 ->
                   state_input4c out (plusPtr inp 1) b1 b2 w8
  
                 | otherwise ->
                   throwDecodeError
  
          state_input4 :: Int -> Ptr Word8 -> Word8 -> IO Text
          state_input4 !out !inp !b1
            | inp == end = throwDecodeError
            | otherwise  = do
              w8 <- peek inp
              if | (w8 .&. 192) == 128 ->
                   state_input4b out (plusPtr inp 1) b1 w8
  
                 | otherwise ->
                   throwDecodeError
  
          state_input3b :: Int -> Ptr Word8 -> Word8 -> Word8 -> IO Text
          state_input3b !out !inp !b1 !b2
            | inp == end = throwDecodeError
            | otherwise  = do
              w8 <- peek inp
              if | (w8 .&. 192) == 128
                 , let acc   = shiftL (fromIntegral (b1 .&. 15)) 12
                 , let acc'  = acc .|.  shiftL (fromIntegral (b2 .&. 63)) 6
                 , let acc'' = acc' .|. fromIntegral (w8 .&. 63) :: Word32
                 , (acc'' >= 2048 && acc'' < 55296) || acc'' > 57343 -> do
                   P.writePrimArray arr out b1
                   write2bytes (out + 1) b2 w8 (plusPtr inp 1)
  
                 | otherwise ->
                   throwDecodeError
  
          state_input3 :: Int -> Ptr Word8 -> Word8 -> IO Text
          state_input3 !out !inp !b1
            | inp == end = throwDecodeError
            | otherwise  = do
              w8 <- peek inp
              if | (w8 .&. 192) == 128 ->
                   state_input3b out (plusPtr inp 1) b1 w8
  
                 | otherwise ->
                   throwDecodeError
  
          state_input2 :: Int -> Ptr Word8 -> Word8 -> IO Text
          state_input2 !out !inp !b1
            | inp == end = throwDecodeError
            | otherwise  = do
              w8 <- peek inp
              if | (w8 .&. 192) == 128,
                   let acc = shiftL (fromIntegral (b1 .&. 63)) 6 :: Word32
                       acc' = acc .|. fromIntegral (w8 .&. 63) :: Word32
                 , acc' >= 128 -> do
                   P.writePrimArray arr out b1
                   write1byte (out + 1) w8 (plusPtr inp 1)
  
                 | otherwise ->
                   throwDecodeError
  
          state_start :: Int -> Ptr Word8 -> IO Text
          state_start !out !inp
            | inp == end = do
              P.shrinkMutablePrimArray arr out
              frozenArr <- P.unsafeFreezePrimArray arr
              return $ case frozenArr of
                P.PrimArray ba -> T.Text (TA.ByteArray ba) 0 out
  
            | otherwise = do
              w8 <- peek inp
              if | w8 == 92 -> state_escape out (plusPtr inp 1)
                 | w8 < 128 -> do
                   P.writePrimArray arr out w8
                   state_start (out + 1) (plusPtr inp 1)
  
                 | w8 < 192 -> throwDecodeError
                 | w8 < 224 -> state_input2 out (plusPtr inp 1) w8
                 | w8 < 240 -> state_input3 out (plusPtr inp 1) w8
                 | w8 < 248 -> state_input4 out (plusPtr inp 1) w8
  
                 | otherwise -> throwDecodeError
  
      -- start the state machine
      state_start (0 :: Int) begin
  
  #endif