module Data.Text.UnsafeChar
(
unsafeChr
, unsafeChr8
, unsafeChr32
, unsafeWrite
) where
import Control.Exception (assert)
import Control.Monad.ST (ST)
import Data.Bits ((.&.))
import Data.Char (ord)
import Data.Text.UnsafeShift (shiftR)
import GHC.Exts (Char(..), chr#, word2Int#)
import GHC.Word (Word8(..), Word16(..), Word32(..))
import qualified Data.Text.Array as A
unsafeChr :: Word16 -> Char
unsafeChr (W16# w#) = C# (chr# (word2Int# w#))
unsafeChr8 :: Word8 -> Char
unsafeChr8 (W8# w#) = C# (chr# (word2Int# w#))
unsafeChr32 :: Word32 -> Char
unsafeChr32 (W32# w#) = C# (chr# (word2Int# w#))
unsafeWrite :: A.MArray s Word16 -> Int -> Char -> ST s Int
unsafeWrite marr i c
| n < 0x10000 = do
assert (i >= 0) . assert (i < A.length marr) $
A.unsafeWrite marr i (fromIntegral n)
return (i+1)
| otherwise = do
assert (i >= 0) . assert (i < A.length marr 1) $
A.unsafeWrite marr i lo
A.unsafeWrite marr (i+1) hi
return (i+2)
where n = ord c
m = n 0x10000
lo = fromIntegral $ (m `shiftR` 10) + 0xD800
hi = fromIntegral $ (m .&. 0x3FF) + 0xDC00