633e189 · typeable/attoparsec

git.iko.soy/typeable/attoparsec

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Rework string for ByteString to fail early (gh-97)

633e189Bryan O'Sullivan12 years ago

Data/Attoparsec/ByteString/Internal.hs+29−1

compare with master

unifiedsplit

@@ -170,9 +170,37 @@ take n = takeWith n (const True)

170-- before failing. In attoparsec, the above parser will /succeed/ on

171-- that input, because the failed first branch will consume nothing.

172string :: ByteString -> Parser ByteString

173+string s = T.Parser $ \t pos more lose succ ->

173−string s = takeWith (B.length s) (==s)

174+ let n = B.length s

175+ in if lengthAtLeast pos n t

176+ then if s == substring pos (Pos n) t

177+ then succ t (pos + Pos n) more s

178+ else lose t pos more [] "string"

179+ else let t' = Buf.unsafeDrop (fromPos pos) t

180+ in if t' `B.isPrefixOf` s

181+ then stringSuspended s (B.drop (B.length t') s)

182+ t pos more lose succ

183+ else lose t pos more [] "string"

174{-# INLINE string #-}

184{-# INLINE string #-}

175

185

186+stringSuspended :: ByteString -> ByteString -> Buffer -> Pos -> More

187+ -> Failure r

188+ -> Success ByteString r

189+ -> Result r

190+stringSuspended s0 s t pos more lose succ =

191+ runParser (demandInput_ >>= go) t pos more lose succ

192+ where go s' = T.Parser $ \t' pos' more' lose' succ' ->

193+ let m = B.length s

194+ n = B.length s'

195+ in if n >= m

196+ then if B.unsafeTake m s' == s

197+ then succ' t' (pos' + Pos (B.length s0)) more' s0

198+ else lose' t' pos' more' [] "string"

199+ else if s' == B.unsafeTake n s

200+ then stringSuspended s0 (B.unsafeDrop n s)

201+ t' pos' more' lose' succ'

202+ else lose' t' pos' more' [] "string"

203+

176stringTransform :: (ByteString -> ByteString) -> ByteString

204stringTransform :: (ByteString -> ByteString) -> ByteString

177 -> Parser ByteString

205 -> Parser ByteString

178stringTransform f s = takeWith (B.length s) ((==f s) . f)

206stringTransform f s = takeWith (B.length s) ((==f s) . f)

Data/Attoparsec/Internal.hs+17−3

@@ -15,6 +15,7 @@ module Data.Attoparsec.Internal

15 ( compareResults

16 , prompt

17 , demandInput

18+ , demandInput_

18 , wantInput

19 , wantInput

19 , endOfInput

20 , endOfInput

20 , atEnd

21 , atEnd

@@ -40,8 +41,8 @@ compareResults (Done t0 r0) (Done t1 r1) =

40compareResults (Partial _) (Partial _) = Nothing

41compareResults (Partial _) (Partial _) = Nothing

41compareResults _ _ = Just False

42compareResults _ _ = Just False

43−-- | Ask for input. If we receive any, pass it to a success

44+-- | Ask for input. If we receive any, pass the augmented input to a

44−-- continuation, otherwise to a failure continuation.

45+-- success continuation, otherwise to a failure continuation.

45prompt :: Chunk t

46prompt :: Chunk t

46 => State t -> Pos -> More

47 => State t -> Pos -> More

47 -> (State t -> Pos -> More -> IResult t r)

48 -> (State t -> Pos -> More -> IResult t r)

@@ -68,12 +69,25 @@ demandInput :: Chunk t => Parser t ()

68demandInput = Parser $ \t pos more lose succ ->

69demandInput = Parser $ \t pos more lose succ ->

69 case more of

70 case more of

70 Complete -> lose t pos more [] "not enough input"

71 Complete -> lose t pos more [] "not enough input"

71− _ -> let lose' t' pos' more' = lose t' pos' more' [] "not enough input"

72+ _ -> let lose' _ pos' more' = lose t pos' more' [] "not enough input"

72 succ' t' pos' more' = succ t' pos' more' ()

73 succ' t' pos' more' = succ t' pos' more' ()

73 in prompt t pos more lose' succ'

74 in prompt t pos more lose' succ'

74{-# SPECIALIZE demandInput :: Parser ByteString () #-}

75{-# SPECIALIZE demandInput :: Parser ByteString () #-}

75{-# SPECIALIZE demandInput :: Parser Text () #-}

76{-# SPECIALIZE demandInput :: Parser Text () #-}

78+-- | Immediately demand more input via a 'Partial' continuation

79+-- result. Return the new input.

80+demandInput_ :: Chunk t => Parser t t

81+demandInput_ = Parser $ \t pos more lose succ ->

82+ case more of

83+ Complete -> lose t pos more [] "not enough input"

84+ _ -> Partial $ \s ->

85+ if nullChunk s

86+ then lose t pos Complete [] "not enough input"

87+ else succ (pappendChunk t s) pos more s

88+{-# SPECIALIZE demandInput_ :: Parser ByteString ByteString #-}

89+{-# SPECIALIZE demandInput_ :: Parser Text Text #-}

90+

77-- | This parser always succeeds. It returns 'True' if any input is

91-- | This parser always succeeds. It returns 'True' if any input is

78-- available either immediately or on demand, and 'False' if the end

92-- available either immediately or on demand, and 'False' if the end

79-- of all input has been reached.

93-- of all input has been reached.