    {-# LANGUAGE BangPatterns #-}

    -- |
    -- Module      : Data.Text.Internal.Encoding.Fusion.Common
    -- Copyright   : (c) Tom Harper 2008-2009,
    --               (c) Bryan O'Sullivan 2009,
    --               (c) Duncan Coutts 2009,
    --               (c) Jasper Van der Jeugt 2011
    --
    -- License     : BSD-style
    -- Maintainer  : bos@serpentine.com
    -- Stability   : experimental
    -- Portability : portable
    --
    -- /Warning/: this is an internal module, and does not have a stable
    -- API or name. Use at your own risk!
    --
    -- Fusible 'Stream'-oriented functions for converting between 'Text'
    -- and several common encodings.

    module Data.Text.Internal.Encoding.Fusion.Common
        (
        -- * Restreaming
        -- Restreaming is the act of converting from one 'Stream'
        -- representation to another.
          restreamUtf16LE
        , restreamUtf16BE
        , restreamUtf32LE
        , restreamUtf32BE
        ) where

    import Data.Bits ((.&.), shiftR)
    import Data.Text.Internal.Fusion (Step(..), Stream(..))
    import Data.Text.Internal.Fusion.Types (RS(..))
    import Data.Text.Internal.Unsafe.Char (ord)
    import Data.Word (Word8)

    restreamUtf16BE :: Stream Char -> Stream Word8
    restreamUtf16BE :: Stream Char -> Stream Word8
    restreamUtf16BE (Stream s -> Step s Char
    next0 s
    s0 Size
    len) = (RS s -> Step (RS s) Word8) -> RS s -> Size -> Stream Word8
    forall a s. (s -> Step s a) -> s -> Size -> Stream a
    Stream RS s -> Step (RS s) Word8
    next (s -> RS s
    forall s. s -> RS s
    RS0 s
    s0) (Size
    len Size -> Size -> Size
    forall a. Num a => a -> a -> a
    * Size
    2)
      where
        next :: RS s -> Step (RS s) Word8
    next (RS0 s
    s) = case s -> Step s Char
    next0 s
    s of
            Step s Char
    Done -> Step (RS s) Word8
    forall s a. Step s a
    Done
            Skip s
    s' -> RS s -> Step (RS s) Word8
    forall s a. s -> Step s a
    Skip (s -> RS s
    forall s. s -> RS s
    RS0 s
    s')
            Yield Char
    x s
    s'
                | Int
    n Int -> Int -> Bool
    forall a. Ord a => a -> a -> Bool
    < Int
    0x10000 -> Word8 -> RS s -> Step (RS s) Word8
    forall s a. a -> s -> Step s a
    Yield (Int -> Word8
    intToWord8 (Int -> Word8) -> Int -> Word8
    forall a b. (a -> b) -> a -> b
    $ Int
    n Int -> Int -> Int
    forall a. Bits a => a -> Int -> a
    `shiftR` Int
    8) (RS s -> Step (RS s) Word8) -> RS s -> Step (RS s) Word8
    forall a b. (a -> b) -> a -> b
    $
                                 s -> Word8 -> RS s
    forall s. s -> Word8 -> RS s
    RS1 s
    s' (Int -> Word8
    intToWord8 Int
    n)
                | Bool
    otherwise   -> Word8 -> RS s -> Step (RS s) Word8
    forall s a. a -> s -> Step s a
    Yield Word8
    c1 (RS s -> Step (RS s) Word8) -> RS s -> Step (RS s) Word8
    forall a b. (a -> b) -> a -> b
    $ s -> Word8 -> Word8 -> Word8 -> RS s
    forall s. s -> Word8 -> Word8 -> Word8 -> RS s
    RS3 s
    s' Word8
    c2 Word8
    c3 Word8
    c4
                where
                  n :: Int
    n  = Char -> Int
    ord Char
    x
                  n1 :: Int
    n1 = Int
    n Int -> Int -> Int
    forall a. Num a => a -> a -> a
    - Int
    0x10000
                  c1 :: Word8
    c1 = Int -> Word8
    intToWord8 (Int
    n1 Int -> Int -> Int
    forall a. Bits a => a -> Int -> a
    `shiftR` Int
    18 Int -> Int -> Int
    forall a. Num a => a -> a -> a
    + Int
    0xD8)
                  c2 :: Word8
    c2 = Int -> Word8
    intToWord8 (Int
    n1 Int -> Int -> Int
    forall a. Bits a => a -> Int -> a
    `shiftR` Int
    10)
                  n2 :: Int
    n2 = Int
    n1 Int -> Int -> Int
    forall a. Bits a => a -> a -> a
    .&. Int
    0x3FF
                  c3 :: Word8
    c3 = Int -> Word8
    intToWord8 (Int
    n2 Int -> Int -> Int
    forall a. Bits a => a -> Int -> a
    `shiftR` Int
    8 Int -> Int -> Int
    forall a. Num a => a -> a -> a
    + Int
    0xDC)
                  c4 :: Word8
    c4 = Int -> Word8
    intToWord8 Int
    n2
        next (RS1 s
    s Word8
    x2)       = Word8 -> RS s -> Step (RS s) Word8
    forall s a. a -> s -> Step s a
    Yield Word8
    x2 (s -> RS s
    forall s. s -> RS s
    RS0 s
    s)
        next (RS2 s
    s Word8
    x2 Word8
    x3)    = Word8 -> RS s -> Step (RS s) Word8
    forall s a. a -> s -> Step s a
    Yield Word8
    x2 (s -> Word8 -> RS s
    forall s. s -> Word8 -> RS s
    RS1 s
    s Word8
    x3)
        next (RS3 s
    s Word8
    x2 Word8
    x3 Word8
    x4) = Word8 -> RS s -> Step (RS s) Word8
    forall s a. a -> s -> Step s a
    Yield Word8
    x2 (s -> Word8 -> Word8 -> RS s
    forall s. s -> Word8 -> Word8 -> RS s
    RS2 s
    s Word8
    x3 Word8
    x4)
        {-# INLINE next #-}
    {-# INLINE restreamUtf16BE #-}

    restreamUtf16LE :: Stream Char -> Stream Word8
    restreamUtf16LE :: Stream Char -> Stream Word8
    restreamUtf16LE (Stream s -> Step s Char
    next0 s
    s0 Size
    len) = (RS s -> Step (RS s) Word8) -> RS s -> Size -> Stream Word8
    forall a s. (s -> Step s a) -> s -> Size -> Stream a
    Stream RS s -> Step (RS s) Word8
    next (s -> RS s
    forall s. s -> RS s
    RS0 s
    s0) (Size
    len Size -> Size -> Size
    forall a. Num a => a -> a -> a
    * Size
    2)
      where
        next :: RS s -> Step (RS s) Word8
    next (RS0 s
    s) = case s -> Step s Char
    next0 s
    s of
            Step s Char
    Done -> Step (RS s) Word8
    forall s a. Step s a
    Done
            Skip s
    s' -> RS s -> Step (RS s) Word8
    forall s a. s -> Step s a
    Skip (s -> RS s
    forall s. s -> RS s
    RS0 s
    s')
            Yield Char
    x s
    s'
                | Int
    n Int -> Int -> Bool
    forall a. Ord a => a -> a -> Bool
    < Int
    0x10000 -> Word8 -> RS s -> Step (RS s) Word8
    forall s a. a -> s -> Step s a
    Yield (Int -> Word8
    intToWord8 Int
    n) (RS s -> Step (RS s) Word8) -> RS s -> Step (RS s) Word8
    forall a b. (a -> b) -> a -> b
    $
                                 s -> Word8 -> RS s
    forall s. s -> Word8 -> RS s
    RS1 s
    s' (Int -> Word8
    intToWord8 (Int -> Word8) -> Int -> Word8
    forall a b. (a -> b) -> a -> b
    $ Int -> Int -> Int
    forall a. Bits a => a -> Int -> a
    shiftR Int
    n Int
    8)
                | Bool
    otherwise   -> Word8 -> RS s -> Step (RS s) Word8
    forall s a. a -> s -> Step s a
    Yield Word8
    c1 (RS s -> Step (RS s) Word8) -> RS s -> Step (RS s) Word8
    forall a b. (a -> b) -> a -> b
    $ s -> Word8 -> Word8 -> Word8 -> RS s
    forall s. s -> Word8 -> Word8 -> Word8 -> RS s
    RS3 s
    s' Word8
    c2 Word8
    c3 Word8
    c4
              where
                n :: Int
    n  = Char -> Int
    ord Char
    x
                n1 :: Int
    n1 = Int
    n Int -> Int -> Int
    forall a. Num a => a -> a -> a
    - Int
    0x10000
                c2 :: Word8
    c2 = Int -> Word8
    intToWord8 (Int -> Int -> Int
    forall a. Bits a => a -> Int -> a
    shiftR Int
    n1 Int
    18 Int -> Int -> Int
    forall a. Num a => a -> a -> a
    + Int
    0xD8)
                c1 :: Word8
    c1 = Int -> Word8
    intToWord8 (Int -> Int -> Int
    forall a. Bits a => a -> Int -> a
    shiftR Int
    n1 Int
    10)
                n2 :: Int
    n2 = Int
    n1 Int -> Int -> Int
    forall a. Bits a => a -> a -> a
    .&. Int
    0x3FF
                c4 :: Word8
    c4 = Int -> Word8
    intToWord8 (Int -> Int -> Int
    forall a. Bits a => a -> Int -> a
    shiftR Int
    n2 Int
    8 Int -> Int -> Int
    forall a. Num a => a -> a -> a
    + Int
    0xDC)
                c3 :: Word8
    c3 = Int -> Word8
    intToWord8 Int
    n2
        next (RS1 s
    s Word8
    x2)       = Word8 -> RS s -> Step (RS s) Word8
    forall s a. a -> s -> Step s a
    Yield Word8
    x2 (s -> RS s
    forall s. s -> RS s
    RS0 s
    s)
        next (RS2 s
    s Word8
    x2 Word8
    x3)    = Word8 -> RS s -> Step (RS s) Word8
    forall s a. a -> s -> Step s a
    Yield Word8
    x2 (s -> Word8 -> RS s
    forall s. s -> Word8 -> RS s
    RS1 s
    s Word8
    x3)
        next (RS3 s
    s Word8
    x2 Word8
    x3 Word8
    x4) = Word8 -> RS s -> Step (RS s) Word8
    forall s a. a -> s -> Step s a
    Yield Word8
    x2 (s -> Word8 -> Word8 -> RS s
    forall s. s -> Word8 -> Word8 -> RS s
    RS2 s
    s Word8
    x3 Word8
    x4)
        {-# INLINE next #-}
    {-# INLINE restreamUtf16LE #-}

    restreamUtf32BE :: Stream Char -> Stream Word8
    restreamUtf32BE :: Stream Char -> Stream Word8
    restreamUtf32BE (Stream s -> Step s Char
    next0 s
    s0 Size
    len) = (RS s -> Step (RS s) Word8) -> RS s -> Size -> Stream Word8
    forall a s. (s -> Step s a) -> s -> Size -> Stream a
    Stream RS s -> Step (RS s) Word8
    next (s -> RS s
    forall s. s -> RS s
    RS0 s
    s0) (Size
    len Size -> Size -> Size
    forall a. Num a => a -> a -> a
    * Size
    2)
      where
        next :: RS s -> Step (RS s) Word8
    next (RS0 s
    s) = case s -> Step s Char
    next0 s
    s of
            Step s Char
    Done       -> Step (RS s) Word8
    forall s a. Step s a
    Done
            Skip s
    s'    -> RS s -> Step (RS s) Word8
    forall s a. s -> Step s a
    Skip (s -> RS s
    forall s. s -> RS s
    RS0 s
    s')
            Yield Char
    x s
    s' -> Word8 -> RS s -> Step (RS s) Word8
    forall s a. a -> s -> Step s a
    Yield Word8
    c1 (s -> Word8 -> Word8 -> Word8 -> RS s
    forall s. s -> Word8 -> Word8 -> Word8 -> RS s
    RS3 s
    s' Word8
    c2 Word8
    c3 Word8
    c4)
              where
                n :: Int
    n  = Char -> Int
    ord Char
    x
                c1 :: Word8
    c1 = Int -> Word8
    intToWord8 (Int -> Word8) -> Int -> Word8
    forall a b. (a -> b) -> a -> b
    $ Int -> Int -> Int
    forall a. Bits a => a -> Int -> a
    shiftR Int
    n Int
    24
                c2 :: Word8
    c2 = Int -> Word8
    intToWord8 (Int -> Word8) -> Int -> Word8
    forall a b. (a -> b) -> a -> b
    $ Int -> Int -> Int
    forall a. Bits a => a -> Int -> a
    shiftR Int
    n Int
    16
                c3 :: Word8
    c3 = Int -> Word8
    intToWord8 (Int -> Word8) -> Int -> Word8
    forall a b. (a -> b) -> a -> b
    $ Int -> Int -> Int
    forall a. Bits a => a -> Int -> a
    shiftR Int
    n Int
    8
                c4 :: Word8
    c4 = Int -> Word8
    intToWord8 Int
    n
        next (RS1 s
    s Word8
    x2)       = Word8 -> RS s -> Step (RS s) Word8
    forall s a. a -> s -> Step s a
    Yield Word8
    x2 (s -> RS s
    forall s. s -> RS s
    RS0 s
    s)
        next (RS2 s
    s Word8
    x2 Word8
    x3)    = Word8 -> RS s -> Step (RS s) Word8
    forall s a. a -> s -> Step s a
    Yield Word8
    x2 (s -> Word8 -> RS s
    forall s. s -> Word8 -> RS s
    RS1 s
    s Word8
    x3)
        next (RS3 s
    s Word8
    x2 Word8
    x3 Word8
    x4) = Word8 -> RS s -> Step (RS s) Word8
    forall s a. a -> s -> Step s a
    Yield Word8
    x2 (s -> Word8 -> Word8 -> RS s
    forall s. s -> Word8 -> Word8 -> RS s
    RS2 s
    s Word8
    x3 Word8
    x4)
        {-# INLINE next #-}
    {-# INLINE restreamUtf32BE #-}

    restreamUtf32LE :: Stream Char -> Stream Word8
    restreamUtf32LE :: Stream Char -> Stream Word8
    restreamUtf32LE (Stream s -> Step s Char
    next0 s
    s0 Size
    len) = (RS s -> Step (RS s) Word8) -> RS s -> Size -> Stream Word8
    forall a s. (s -> Step s a) -> s -> Size -> Stream a
    Stream RS s -> Step (RS s) Word8
    next (s -> RS s
    forall s. s -> RS s
    RS0 s
    s0) (Size
    len Size -> Size -> Size
    forall a. Num a => a -> a -> a
    * Size
    2)
      where
        next :: RS s -> Step (RS s) Word8
    next (RS0 s
    s) = case s -> Step s Char
    next0 s
    s of
            Step s Char
    Done       -> Step (RS s) Word8
    forall s a. Step s a
    Done
            Skip s
    s'    -> RS s -> Step (RS s) Word8
    forall s a. s -> Step s a
    Skip (s -> RS s
    forall s. s -> RS s
    RS0 s
    s')
            Yield Char
    x s
    s' -> Word8 -> RS s -> Step (RS s) Word8
    forall s a. a -> s -> Step s a
    Yield Word8
    c1 (s -> Word8 -> Word8 -> Word8 -> RS s
    forall s. s -> Word8 -> Word8 -> Word8 -> RS s
    RS3 s
    s' Word8
    c2 Word8
    c3 Word8
    c4)
              where
                n :: Int
    n  = Char -> Int
    ord Char
    x
                c4 :: Word8
    c4 = Int -> Word8
    intToWord8 (Int -> Word8) -> Int -> Word8
    forall a b. (a -> b) -> a -> b
    $ Int -> Int -> Int
    forall a. Bits a => a -> Int -> a
    shiftR Int
    n Int
    24
                c3 :: Word8
    c3 = Int -> Word8
    intToWord8 (Int -> Word8) -> Int -> Word8
    forall a b. (a -> b) -> a -> b
    $ Int -> Int -> Int
    forall a. Bits a => a -> Int -> a
    shiftR Int
    n Int
    16
                c2 :: Word8
    c2 = Int -> Word8
    intToWord8 (Int -> Word8) -> Int -> Word8
    forall a b. (a -> b) -> a -> b
    $ Int -> Int -> Int
    forall a. Bits a => a -> Int -> a
    shiftR Int
    n Int
    8
                c1 :: Word8
    c1 = Int -> Word8
    intToWord8 Int
    n
        next (RS1 s
    s Word8
    x2)       = Word8 -> RS s -> Step (RS s) Word8
    forall s a. a -> s -> Step s a
    Yield Word8
    x2 (s -> RS s
    forall s. s -> RS s
    RS0 s
    s)
        next (RS2 s
    s Word8
    x2 Word8
    x3)    = Word8 -> RS s -> Step (RS s) Word8
    forall s a. a -> s -> Step s a
    Yield Word8
    x2 (s -> Word8 -> RS s
    forall s. s -> Word8 -> RS s
    RS1 s
    s Word8
    x3)
        next (RS3 s
    s Word8
    x2 Word8
    x3 Word8
    x4) = Word8 -> RS s -> Step (RS s) Word8
    forall s a. a -> s -> Step s a
    Yield Word8
    x2 (s -> Word8 -> Word8 -> RS s
    forall s. s -> Word8 -> Word8 -> RS s
    RS2 s
    s Word8
    x3 Word8
    x4)
        {-# INLINE next #-}
    {-# INLINE restreamUtf32LE #-}

    intToWord8 :: Int -> Word8
    intToWord8 :: Int -> Word8
    intToWord8 = Int -> Word8
    forall a b. (Integral a, Num b) => a -> b
    fromIntegral