module Text.Builder.UTF16
where
import Text.Builder.Prelude
type UTF16View =
forall x. (Word16 -> x) -> (Word16 -> Word16 -> x) -> x
{-# INLINE char #-}
char :: Char -> UTF16View
char =
unicodeCodePoint . ord
{-# INLINE unicodeCodePoint #-}
unicodeCodePoint :: Int -> UTF16View
unicodeCodePoint x case1 case2 =
if x < 0x10000
then case1 (fromIntegral x)
else case2 case2Unit1 case2Unit2
where
m =
x - 0x10000
case2Unit1 =
fromIntegral (shiftR m 10 + 0xD800)
case2Unit2 =
fromIntegral ((m .&. 0x3FF) + 0xDC00)
{-# INLINE utf8CodeUnits1 #-}
utf8CodeUnits1 :: Word8 -> UTF16View
utf8CodeUnits1 x case1 _ =
case1 (fromIntegral x)
{-# INLINE utf8CodeUnits2 #-}
utf8CodeUnits2 :: Word8 -> Word8 -> UTF16View
utf8CodeUnits2 byte1 byte2 case1 _ =
case1 (shiftL (fromIntegral byte1 - 0xC0) 6 + fromIntegral byte2 - 0x80)
{-# INLINE utf8CodeUnits3 #-}
utf8CodeUnits3 :: Word8 -> Word8 -> Word8 -> UTF16View
utf8CodeUnits3 byte1 byte2 byte3 case1 case2 =
unicodeCodePoint unicode case1 case2
where
unicode =
shiftL (fromIntegral byte1 - 0xE0) 12 +
shiftL (fromIntegral byte2 - 0x80) 6 +
fromIntegral byte3 - 0x80
{-# INLINE utf8CodeUnits4 #-}
utf8CodeUnits4 :: Word8 -> Word8 -> Word8 -> Word8 -> UTF16View
utf8CodeUnits4 byte1 byte2 byte3 byte4 case1 case2 =
unicodeCodePoint unicode case1 case2
where
unicode =
shiftL (fromIntegral byte1 - 0xE0) 18 +
shiftL (fromIntegral byte2 - 0x80) 12 +
shiftL (fromIntegral byte3 - 0x80) 6 +
fromIntegral byte4 - 0x80