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|
{-# LANGUAGE MagicHash, BangPatterns #-}
-- |
-- Module : Data.Text.Internal.Encoding.Utf16
-- Copyright : (c) 2008, 2009 Tom Harper,
-- (c) 2009 Bryan O'Sullivan,
-- (c) 2009 Duncan Coutts
--
-- License : BSD-style
-- Maintainer : bos@serpentine.com
-- Stability : experimental
-- Portability : GHC
--
-- /Warning/: this is an internal module, and does not have a stable
-- API or name. Functions in this module may not check or enforce
-- preconditions expected by public modules. Use at your own risk!
--
-- Basic UTF-16 validation and character manipulation.
module Data.Text.Internal.Encoding.Utf16
(
chr2
, validate1
, validate2
) where
import GHC.Exts
import GHC.Word (Word16(..))
chr2 :: Word16 -> Word16 -> Char
chr2 (W16# a#) (W16# b#) = C# (chr# (upper# +# lower# +# 0x10000#))
where
!x# = word2Int# a#
!y# = word2Int# b#
!upper# = uncheckedIShiftL# (x# -# 0xD800#) 10#
!lower# = y# -# 0xDC00#
{-# INLINE chr2 #-}
validate1 :: Word16 -> Bool
validate1 x1 = x1 < 0xD800 || x1 > 0xDFFF
{-# INLINE validate1 #-}
validate2 :: Word16 -> Word16 -> Bool
validate2 x1 x2 = x1 >= 0xD800 && x1 <= 0xDBFF &&
x2 >= 0xDC00 && x2 <= 0xDFFF
{-# INLINE validate2 #-}
|
