{-# OPTIONS_GHC -fno-warn-unused-imports #-} -- ignore warning from 'import Data.Text.Encoding' -- | -- Module : Blaze.ByteString.Builder.Char.Utf8 -- Copyright : (c) 2010 Jasper Van der Jeugt & Simon Meier -- License : BSD3-style (see LICENSE) -- -- Maintainer : Simon Meier <iridcode@gmail.com> -- Stability : experimental -- Portability : tested on GHC only -- -- 'Write's and 'Builder's for serializing Unicode characters using the UTF-8 -- encoding. -- module Blaze.ByteString.Builder.Char.Utf8 ( -- * Writing UTF-8 encoded characters to a buffer writeChar -- * Creating Builders from UTF-8 encoded characters , fromChar , fromString , fromShow , fromText , fromLazyText ) where import Foreign import Data.Char (ord) import qualified Data.Text as TS import qualified Data.Text.Encoding as TS -- imported for documentation links import qualified Data.Text.Lazy as TL import qualified Data.Text.Lazy.Encoding as TS -- imported for documentation links import Blaze.ByteString.Builder.Internal -- | Write a UTF-8 encoded Unicode character to a buffer. -- {-# INLINE writeChar #-} writeChar :: Char -> Write writeChar c = boundedWrite 4 (encodeCharUtf8 f1 f2 f3 f4 c) where f1 x1 = pokeN 1 $ \op -> do pokeByteOff op 0 x1 f2 x1 x2 = pokeN 2 $ \op -> do pokeByteOff op 0 x1 pokeByteOff op 1 x2 f3 x1 x2 x3 = pokeN 3 $ \op -> do pokeByteOff op 0 x1 pokeByteOff op 1 x2 pokeByteOff op 2 x3 f4 x1 x2 x3 x4 = pokeN 4 $ \op -> do pokeByteOff op 0 x1 pokeByteOff op 1 x2 pokeByteOff op 2 x3 pokeByteOff op 3 x4 -- | Encode a Unicode character to another datatype, using UTF-8. This function -- acts as an abstract way of encoding characters, as it is unaware of what -- needs to happen with the resulting bytes: you have to specify functions to -- deal with those. -- encodeCharUtf8 :: (Word8 -> a) -- ^ 1-byte UTF-8 -> (Word8 -> Word8 -> a) -- ^ 2-byte UTF-8 -> (Word8 -> Word8 -> Word8 -> a) -- ^ 3-byte UTF-8 -> (Word8 -> Word8 -> Word8 -> Word8 -> a) -- ^ 4-byte UTF-8 -> Char -- ^ Input 'Char' -> a -- ^ Result encodeCharUtf8 f1 f2 f3 f4 c = case ord c of x | x <= 0x7F -> f1 $ fromIntegral x | x <= 0x07FF -> let x1 = fromIntegral $ (x `shiftR` 6) + 0xC0 x2 = fromIntegral $ (x .&. 0x3F) + 0x80 in f2 x1 x2 | x <= 0xFFFF -> let x1 = fromIntegral $ (x `shiftR` 12) + 0xE0 x2 = fromIntegral $ ((x `shiftR` 6) .&. 0x3F) + 0x80 x3 = fromIntegral $ (x .&. 0x3F) + 0x80 in f3 x1 x2 x3 | otherwise -> let x1 = fromIntegral $ (x `shiftR` 18) + 0xF0 x2 = fromIntegral $ ((x `shiftR` 12) .&. 0x3F) + 0x80 x3 = fromIntegral $ ((x `shiftR` 6) .&. 0x3F) + 0x80 x4 = fromIntegral $ (x .&. 0x3F) + 0x80 in f4 x1 x2 x3 x4 {-# INLINE encodeCharUtf8 #-} -- | /O(1)/. Serialize a Unicode character using the UTF-8 encoding. -- fromChar :: Char -> Builder fromChar = fromWriteSingleton writeChar -- | /O(n)/. Serialize a Unicode 'String' using the UTF-8 encoding. -- fromString :: String -> Builder fromString = fromWriteList writeChar -- Performance note: ^^^ -- -- fromWrite2List made things slightly worse for the blaze-html benchmarks -- despite being better when serializing only a list. Probably, the cache is -- already occupied enough with dealing with the data from Html rendering. -- -- | /O(n)/. Serialize a value by 'Show'ing it and UTF-8 encoding the resulting -- 'String'. -- fromShow :: Show a => a -> Builder fromShow = fromString . show -- | /O(n)/. Serialize a strict Unicode 'TS.Text' value using the UTF-8 encoding. -- fromText :: TS.Text -> Builder fromText = fromString . TS.unpack {-# INLINE fromText #-} -- | /O(n)/. Serialize a lazy Unicode 'TL.Text' value using the UTF-8 encoding. -- fromLazyText :: TL.Text -> Builder fromLazyText = fromString . TL.unpack {-# INLINE fromLazyText #-}