From: Ramakrishnan Muthukrishnan Date: Wed, 4 Feb 2015 09:32:16 +0000 (+0530) Subject: much better handling of bencode integers X-Git-Url: https://git.rkrishnan.org/?a=commitdiff_plain;h=6486894bfc71ea04b77cf4912d169763b64ca629;p=functorrent.git much better handling of bencode integers --- diff --git a/src/Bencode.hs b/src/Bencode.hs index adc6d1a..1fb2a31 100644 --- a/src/Bencode.hs +++ b/src/Bencode.hs @@ -17,6 +17,9 @@ data BVal = | Bdict (M.Map BVal BVal) deriving (Ord, Eq) +-- $setup +-- >>> import Data.Either + -- | parse strings -- -- >>> parse bencStr "Bstr" (BC.pack "4:spam") @@ -36,21 +39,33 @@ bencStr = do _ <- spaces -- -- >>> parse bencInt "Bint" (BC.pack "i42e") -- Right 42 +-- >>> parse bencInt "Bint" (BC.pack "i123e") +-- Right 123 -- >>> parse bencInt "Bint" (BC.pack "i1e") -- Right 1 -- >>> parse bencInt "Bint" (BC.pack "i0e") -- Right 0 -- >>> parse bencInt "Bint" (BC.pack "i-1e") -- Right (-1) +-- >>> isLeft $ parse bencInt "Bint" (BC.pack "i01e") +-- True +-- >>> isLeft $ parse bencInt "Bint" (BC.pack "i00e") +-- True +-- >>> isLeft $ parse bencInt "Bint" (BC.pack "i002e") +-- True bencInt :: ParsecBS.Parser Integer bencInt = do _ <- spaces ds <- between (char 'i') (char 'e') numbers return (read ds) where numbers = do d' <- (char '-' <|> digit) ds' <- many digit - if d' == '0' && ds' /= [] - then unexpected "numbers cannot be left-padded with zeros" - else return (d' : ds') + parseNumber d' ds' + parseNumber '0' [] = return ['0'] + parseNumber '-' [] = unexpected "sign without any digits" + parseNumber '0' ds'' = unexpected "numbers cannot be left-padded with zeros" + parseNumber '-' (d'':ds'') | d'' == '0' = unexpected "numbers cannot be left-padded with zeros" + parseNumber '-' ds'' = return ('-':ds'') + parseNumber d'' ds'' = return (d'':ds'') bencParser :: ParsecBS.Parser BVal bencParser = Bstr <$> bencStr <|>