Codec.ByteString.Parser

A monad for efficiently building structures from encoded lazy ByteStrings.

The Parser type

data Parser a

The Get monad is just a State monad carrying around the input ByteString

Instances

Monad Parser

Functor Parser

MonadPlus Parser

Applicative Parser

Alternative Parser

runParser :: Parser a -> ByteString -> Either String a

Run the Get monad applies a get-based parser on the input ByteString

runParserState :: Parser a -> ByteString -> Int64 -> Either String (a, ByteString, Int64)

Run the Get monad applies a get-based parser on the input ByteString. Additional to the result of get it returns the number of consumed bytes and the rest of the input.

Parsing

choice :: [Parser a] -> Parser a

expect :: (Show a, Eq a) => (a -> Bool) -> Parser a -> Parser a

skip :: Word64 -> Parser ()

Skip ahead n bytes. Fails if fewer than n bytes are available.

lookAhead :: Parser a -> Parser a

Run ga, but return without consuming its input. Fails if ga fails.

lookAheadM :: Parser (Maybe a) -> Parser (Maybe a)

Like lookAhead, but consume the input if gma returns 'Just _'. Fails if gma fails.

lookAheadE :: Parser (Either a b) -> Parser (Either a b)

Like lookAhead, but consume the input if gea returns 'Right _'. Fails if gea fails.

Utility

bytesRead :: Parser Int64

Get the total number of bytes read to this point.

getBytes :: Int -> Parser ByteString

Pull n bytes from the input, as a strict ByteString.

remaining :: Parser Int64

Get the number of remaining unparsed bytes. Useful for checking whether all input has been consumed. Note that this forces the rest of the input.

isEmpty :: Parser Bool

Test whether all input has been consumed, i.e. there are no remaining unparsed bytes.

Parsing particular types

satisfy :: (Word8 -> Bool) -> Parser Word8

getString :: Int -> Parser String

getStringNul :: Parser String

string :: String -> Parser String

getWord8 :: Parser Word8

Read a Word8 from the monad state

getInt8 :: Parser Int8

word8 :: Word8 -> Parser Word8

int8 :: Int8 -> Parser Int8

ByteStrings

getByteString :: Int -> Parser ByteString

An efficient get method for strict ByteStrings. Fails if fewer than n bytes are left in the input.

getLazyByteString :: Int64 -> Parser ByteString

An efficient get method for lazy ByteStrings. Does not fail if fewer than n bytes are left in the input.

getLazyByteStringNul :: Parser ByteString

Get a lazy ByteString that is terminated with a NUL byte. Fails if it reaches the end of input without hitting a NUL.

getRemainingLazyByteString :: Parser ByteString

Get the remaining bytes as a lazy ByteString

Big-endian reads

getWord16be :: Parser Word16

Read a Word16 in big endian format

word16be :: Word16 -> Parser Word16

getWord24be :: Parser Word32

Read a 24 bit word into Word32 in big endian format

word24be :: Word32 -> Parser Word32

getWord32be :: Parser Word32

Read a Word32 in big endian format

word32be :: Word32 -> Parser Word32

getWord64be :: Parser Word64

Read a Word64 in big endian format

word64be :: Word64 -> Parser Word64

getInt16be :: Parser Int16

int16be :: Int16 -> Parser Int16

getInt32be :: Parser Int32

int32be :: Int32 -> Parser Int32

getInt64be :: Parser Int64

int64be :: Int64 -> Parser Int64

Little-endian reads

getWord16le :: Parser Word16

Read a Word16 in little endian format

word16le :: Word16 -> Parser Word16

getWord24le :: Parser Word32

word24le :: Word32 -> Parser Word32

getWord32le :: Parser Word32

Read a Word32 in little endian format

word32le :: Word32 -> Parser Word32

getWord64le :: Parser Word64

Read a Word64 in little endian format

word64le :: Word64 -> Parser Word64

getInt16le :: Parser Int16

int16le :: Int16 -> Parser Int16

getInt32le :: Parser Int32

int32le :: Int32 -> Parser Int32

getInt64le :: Parser Int64

int64le :: Int64 -> Parser Int64

Host-endian, unaligned reads

getWordHost :: Parser Word

O(1). Read a single native machine word. The word is read in host order, host endian form, for the machine you're on. On a 64 bit machine the Word is an 8 byte value, on a 32 bit machine, 4 bytes.

wordHost :: Word -> Parser Word

getWord16host :: Parser Word16

O(1). Read a 2 byte Word16 in native host order and host endianness.

word16host :: Word16 -> Parser Word16

getWord32host :: Parser Word32

O(1). Read a Word32 in native host order and host endianness.

word32host :: Word32 -> Parser Word32

getWord64host :: Parser Word64

O(1). Read a Word64 in native host order and host endianess.

word64host :: Word64 -> Parser Word64

getVarLenBe :: Parser Word64

varLenBe :: Word64 -> Parser Word64

getVarLenLe :: Parser Word64

varLenLe :: Word64 -> Parser Word64