{-# OPTIONS -fglasgow-exts -fallow-overlapping-instances -fallow-incoherent-instances #-} ---------------------------------------------------------------------- -- | -- Module : Text.JSON -- Copyright : (c) Masahiro Sakai 2006, Jun Mukai 2006 -- License : BSD-style (see the file LICENSE) -- -- Maintainer : mukai@jmuk.org -- Stability : experimental -- Portability : portable -- -- A JSON Parser and Serializer and type classes. -- This code is originally written by Masahiro Sakai. -- The original code can be seen at -- module Text.JSON ( -- * Basic Type and Type Class Jsonable(..) , JsonNode(..) -- * conversion Between String and Jsonable , parse, parse' , toDoc, toDocPP, pp, toDocRaw, toDocPPRaw -- * converters and encode checkers , toJsonString , encoder , utf8Conv, utf16BEConv, utf16LEConv, utf32BEConv, utf32LEConv ) where import Control.Monad hiding (join) import Text.Packrat.Parse import Text.Packrat.Pos import Text.Printf (printf) import Data.Char (ord, chr, isControl) import Data.List (intersperse) import qualified Data.Map as M import Data.Bits ((.|.), (.&.), shiftL, shiftR) import Data.Word (Word8) import Numeric (readHex, showHex) import Text.PrettyPrint.HughesPJ hiding (char) import Data.ByteString.Char8 (ByteString, pack, unpack) import qualified Data.ByteString.Char8 as BS class Jsonable a where fromJson :: JsonNode -> a toJson :: a -> JsonNode jRead :: String -> a jShow :: a -> String jRead = fromJson . parse jShow = show . toDoc . toJson instance Jsonable String where fromJson (String s) = s fromJson _ = error "type mismatch" toJson = String instance Jsonable ByteString where fromJson (String s) = pack s fromJson _ = error "type mismatch" toJson = String . unpack instance Jsonable Integer where fromJson (Number n) = floor n fromJson _ = error "type mismatch" toJson = Number . fromIntegral instance Jsonable Int where fromJson (Number n) = floor n fromJson _ = error "type mismatch" toJson = Number . fromIntegral instance Jsonable Double where fromJson (Number n) = n fromJson _ = error "type mismatch" toJson = Number instance Jsonable Float where fromJson (Number n) = realToFrac n fromJson _ = error "type mismatch" toJson = Number . realToFrac instance Jsonable Rational where fromJson (Number n) = toRational n fromJson _ = error "type mismatch" toJson = Number . fromRational instance (Jsonable a) => Jsonable (M.Map String a) where fromJson (Object m) = M.map fromJson m fromJson _ = error "type mismatch" toJson = Object . M.map toJson instance (Jsonable a) => Jsonable [(String, a)] where fromJson (Object m) = M.toList $ M.map fromJson m fromJson _ = error "type mismatch" toJson = Object . M.map toJson . M.fromList instance (Jsonable a) => Jsonable [a] where fromJson (Array a) = map fromJson a fromJson _ = error "type mismatch" toJson a = Array $ map toJson a instance Jsonable Bool where fromJson (Bool b) = b fromJson _ = error "type mismatch" toJson = Bool instance (Jsonable a) => Jsonable (Maybe a) where fromJson Null = Nothing fromJson a = Just $ fromJson a toJson Nothing = Null toJson (Just x) = toJson x instance Jsonable JsonNode where fromJson = id toJson = id data JsonNode = String String | Number !Double | Object !(M.Map String JsonNode) | Array [JsonNode] | Bool !Bool | Null deriving (Eq, Show) data JsonDerivs = JsonDerivs { dvNode :: Result JsonDerivs JsonNode , dvStr :: Result JsonDerivs String , dvNumber :: Result JsonDerivs Double , dvObject :: Result JsonDerivs (M.Map String JsonNode) , dvArray :: Result JsonDerivs [JsonNode] , advChar :: Result JsonDerivs Char , advPos :: Pos } instance Derivs JsonDerivs where dvChar = advChar dvPos = advPos tok :: Derivs d => Parser d a -> Parser d a tok p = do{ x <- p; spaces; return x } pValue :: JsonDerivs -> Result JsonDerivs JsonNode Parser pValue = msum [ liftM String (Parser dvStr) , liftM Number (Parser dvNumber) , liftM Object (Parser dvObject) , liftM Array (Parser dvArray) , string "true" >> return (Bool True) , string "false" >> return (Bool False) , string "null" >> return Null ] pStr :: JsonDerivs -> Result JsonDerivs String Parser pStr = between (char '"') (char '"') $ many c1 where c1 = charIf (\c -> not (c=='"' || c=='\\' || isControl c)) <|> (char '\\' >> c2) c2 = msum [ char '"' , char '\\' , char '/' , char 'b' >> return '\b' , char 'f' >> return '\f' , char 'n' >> return '\n' , char 'r' >> return '\r' , char 't' >> return '\t' , char 'u' >> do xs@[x1,x2,x3,x4] <- count 4 hexDigit if x1 `elem` "dD" && x2 `elem` "89abAB" then surrogatePair x2 x3 x4 else return $ read $ "'\\x"++xs++"'" ] surrogatePair x2 x3 x4 = do char '\\' >> char 'u' [y1, y2, y3, y4] <- count 4 hexDigit if y1 `elem` "dD" && y2 `elem` "cCdDeEfF" then let x2' = fst (head $ readHex [x2]) - 8 y2' = fst (head $ readHex [y2]) - 12 xlow = fst $ head $ readHex [x3, x4] ylow = fst $ head $ readHex [y3, y4] shifts = [18, 10, 8, 0] in return $ chr $ 0x10000 + foldl1 (.|.) (zipWith shiftL [x2',xlow,y2',ylow] shifts) else fail "" (>>+) :: Monad m => m [a] -> m [a] -> m [a] ma >>+ mb = ma >>= \a -> mb >>= \b -> return (a++b) pNumber :: JsonDerivs -> Result JsonDerivs Double Parser pNumber = liftM read $ int >>+ option "" frac >>+ option "" exp where digits = many digit int = do s <- option "" (string "-") x <- oneOf ['1'..'9'] xs <- digits return (s++x:xs) frac = char '.' >> liftM ('.':) (many1 digit) exp = e >>+ digits e = do a <- char 'e' <|> char 'E' liftM (a:) (string "+" <|> string "-" <|> string "") pObject :: JsonDerivs -> Result JsonDerivs (M.Map String JsonNode) Parser pObject = liftM M.fromList $ between (tok (char '{')) (char '}') $ tok member `sepBy` tok (char ',') where member = do k <- tok (Parser dvStr) tok (char ':') v <- Parser dvNode return (k,v) pArray :: JsonDerivs -> Result JsonDerivs [JsonNode] Parser pArray = between (tok (char '[')) (char ']') $ tok (Parser dvNode) `sepBy` tok (char ',') parse :: String -> JsonNode parse s = case dvNode (derive (Pos "JSON parser" 1 1) s) of Parsed v d' e' -> v NoParse e -> error (show e) where derive pos s = d where d = JsonDerivs nod str num obj arr chr pos nod = pValue d str = pStr d num = pNumber d obj = pObject d arr = pArray d chr = case s of (c:s') -> Parsed c (derive (nextPos pos c) s') (nullError d) _ -> NoParse (eofError d) parse' :: ByteString -> JsonNode parse' s = case dvNode (derive (Pos "JSON parser" 1 1) s) of Parsed v d' e' -> v NoParse e -> error (show e) where derive pos s = d where d = JsonDerivs nod str num obj arr chr pos nod = pValue d str = pStr d num = pNumber d obj = pObject d arr = pArray d chr = if BS.null s then NoParse (eofError d) else let (c, s') = (BS.head s, BS.tail s) in Parsed c (derive (nextPos pos c) s') (nullError d) toDoc :: JsonNode -> Doc toDoc = stringifyDoc hsep True toDocPP :: JsonNode -> Doc toDocPP = stringifyDoc fsep True pp :: Jsonable a => a -> String pp = show . toDocPP . toJson toDocRaw :: JsonNode -> Doc toDocRaw = stringifyDoc hsep False toDocPPRaw :: JsonNode -> Doc toDocPPRaw = stringifyDoc fsep False stringifyDoc _ f (String s) = stringifyString s f stringifyDoc _ _ (Number x) | isInfinite x = error "can't stringify infinity" | isNaN x = error "can't stringify NaN" | otherwise = double x stringifyDoc sep f (Object m) = lbrace <+> join comma [sep [stringifyString k f <> colon, nest 2 (stringifyDoc sep f v)] | (k,v) <- M.toList m] $$ rbrace stringifyDoc sep f (Array xs) = lbrack <+> join comma (map (stringifyDoc sep f) xs) <+> rbrack stringifyDoc _ _ (Bool b) = if b then text "true" else text "false" stringifyDoc _ _ Null = text "null" stringifyString :: String -> Bool -> Doc stringifyString s b = doubleQuotes $ text $ concatMap (f b) s where f _ '"' = "\\\"" f _ '\\' = "\\\\" f _ '\b' = "\\b" f _ '\f' = "\\f" f _ '\n' = "\\n" f _ '\r' = "\\r" f _ '\t' = "\\t" f _ '\DEL' = "\\u007f" f True c = charToUTFChars c f _ c | c' > 0xffff = decSurrogates $ ord c | c' > 0x00ff = printf "\\u%04x" c | c' < 0x0020 = printf "\\u%04x" c | otherwise = [c] where c' = ord c decSurrogates c = let high = (c - 0x10000) `shiftR` 10 .|. 0xd800 low = c .&. 0x3ff .|. 0xdc00 in "\\u" ++ showHex high ("\\u" ++ showHex low "") charToUTFChars c | c' < 0x7f = [c] | c' < 0x7ff = chars 2 | c' < 0xffff = chars 3 | c' < 0x1fffff = chars 4 | c' < 0x3ffffff = chars 5 | otherwise = chars 6 where c' = ord c shifts = [30, 24, 18, 12, 6, 0] headMasks = [0xc0, 0xe0, 0xf0, 0xf8, 0xfc] maskShift s = 0x80 .|. ((c' `shiftR` s) .&. 0x3f) chars n = let (h:t) = map maskShift $ drop (6-n) shifts in map chr ((h .|. (headMasks !! (n-2))) : t) join :: Doc -> [Doc] -> Doc join s = fcat . punctuate s ---------------------------------------------------------------------- -- string converter -- toJsonString :: [Word8] -> String toJsonString s = (encoder s) s encoder :: [Word8] -> ([Word8] -> String) encoder (0:0:0:_:_) = utf32BEConv encoder (_:0:0:0:_) = utf32LEConv encoder (0:_:_) = utf16BEConv encoder (_:0:_) = utf16LEConv encoder _ = utf8Conv utf8Conv :: [Word8] -> String utf8Conv [] = [] utf8Conv (c:cs) | c < 0xc0 = chr (fromIntegral c) : utf8Conv cs | c < 0xe0 = conv 1 | c < 0xf0 = conv 2 | c < 0xf8 = conv 3 | c < 0xfc = conv 4 | otherwise = conv 5 where conv n = let (hd, tl) = splitAt n cs c' = fromIntegral c in utf8CharsToChar n c' (map fromIntegral hd) : utf8Conv tl utf8CharsToChar :: Int -> Int -> [Int] -> Char utf8CharsToChar n c cs = chr $ foldl f ((c .&. mask) `shiftL` hs) $ zip shifts $ map (.&. 0x3f) cs where (hs:shifts) = drop (5-n) [30,24,18,12,6,0] mask = [0x1f,0x0f, 0x07, 0x03, 0x01] !! n f c' (s, c) = c' .|. (c `shiftL` s) utf16Conv :: (Int -> Int -> Int) -> [Word8] -> String utf16Conv _ [] = "" utf16Conv _ [_] = "" utf16Conv f (c1:c2:cs) = let c = f (fromIntegral c1) (fromIntegral c2) in if (c .&. 0xd800) == 0xd800 then surrogatePair c cs else chr (c + 0x10000) : utf16Conv f cs where surrogatePair c (c1:c2:cs) = if (c' .&. 0xdc00) == 0xdc00 then chr (high .|. low) : utf16Conv f cs else error "invalid UTF-16 encoding" where c' = f (fromIntegral c1) (fromIntegral c2) high = (c .&. 0x03ff) `shiftL` 10 low = c' .&. 0x03ff surrogatePair c _ = error "invalid UTF-16 encoding" nextChar (c1:c2:cs) = (f (fromIntegral c1) (fromIntegral c2), cs) utf16LEConv :: [Word8] -> String utf16LEConv = utf16Conv f where f c1 c2 = c2 `shiftL` 8 .|. c1 utf16BEConv :: [Word8] -> String utf16BEConv = utf16Conv f where f c1 c2 = c1 `shiftL` 8 .|. c2 utf32Conv :: [Int] -> [Word8] -> String utf32Conv shifts (c1:c2:c3:c4:cs) = chr (f $ map fromIntegral [c1, c2, c3, c4]) : utf32Conv shifts cs where f cs = foldl1 (.|.) $ zipWith (\c s -> shiftL c s) cs shifts utf32Conv _ _ = "" utf32BEConv :: [Word8] -> String utf32BEConv = utf32Conv [24,16,8,0] utf32LEConv :: [Word8] -> String utf32LEConv = utf32Conv [0,8,16,24]
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