Data.Binary.Get

The Get monad. A monad for efficiently building structures from encoded lazy ByteStrings

The Get type

data Get a

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

Instances

Monad Get

Functor Get

MonadFix Get

runGet :: Get a -> ByteString -> a

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

runGetState :: Get a -> ByteString -> Int64 -> (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

skip :: Int -> Get ()

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

uncheckedSkip :: Int64 -> Get ()

Skip ahead n bytes. No error if there isn't enough bytes.

lookAhead :: Get a -> Get a

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

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

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

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

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

uncheckedLookAhead :: Int64 -> Get ByteString

Get the next up to n bytes as a lazy ByteString, without consuming them.

Utility

bytesRead :: Get Int64

Get the total number of bytes read to this point.

getBytes :: Int -> Get ByteString

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

important

remaining :: Get 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 :: Get Bool

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

Parsing particular types

getWord8 :: Get Word8

Read a Word8 from the monad state

ByteStrings

getByteString :: Int -> Get ByteString

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

getLazyByteString :: Int64 -> Get ByteString

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

getLazyByteStringNul :: Get 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 :: Get ByteString

Get the remaining bytes as a lazy ByteString

Big-endian reads

getWord16be :: Get Word16

Read a Word16 in big endian format

getWord32be :: Get Word32

Read a Word32 in big endian format

getWord64be :: Get Word64

Read a Word64 in big endian format

Little-endian reads

getWord16le :: Get Word16

Read a Word16 in little endian format

getWord32le :: Get Word32

Read a Word32 in little endian format

getWord64le :: Get Word64

Read a Word64 in little endian format

Host-endian, unaligned reads

getWordhost :: Get 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.

getWord16host :: Get Word16

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

getWord32host :: Get Word32

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

getWord64host :: Get Word64

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