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module TextBuilderCore.Utf8View where
import TextBuilderCore.Prelude
-- |
-- A matching function, which chooses the continuation to run.
type Utf8View =
forall x.
(Word8 -> x) ->
(Word8 -> Word8 -> x) ->
(Word8 -> Word8 -> Word8 -> x) ->
(Word8 -> Word8 -> Word8 -> Word8 -> x) ->
x
{-# INLINE unicodeCodepoint #-}
unicodeCodepoint :: Int -> Utf8View
unicodeCodepoint x case1 case2 case3 case4
| x < 0x80 = case1 (fromIntegral x)
| x < 0x800 =
case2
(fromIntegral $ x `shiftR` 6 .|. 0xC0)
(fromIntegral $ (x .&. 0x3F) .|. 0x80)
| x < 0x10000 =
case3
(fromIntegral $ x `shiftR` 12 .|. 0xE0)
(fromIntegral $ (x `shiftR` 6) .&. 0x3F .|. 0x80)
(fromIntegral $ (x .&. 0x3F) .|. 0x80)
| otherwise =
case4
(fromIntegral $ x `shiftR` 18 .|. 0xF0)
(fromIntegral $ (x `shiftR` 12) .&. 0x3F .|. 0x80)
(fromIntegral $ (x `shiftR` 6) .&. 0x3F .|. 0x80)
(fromIntegral $ (x .&. 0x3F) .|. 0x80)
|
