binary-strict-0.4.8: Binary deserialisation using strict ByteStrings

Portabilityportable to Hugs and GHC.
MaintainerAdam Langley <>




This is a version of the Get monad for incremental parsing. The parser is written as if a single, huge, strict ByteString was to be parsed. It produces results as it parses by calling yield.

However, if the parser runs out of data, rather than failing the caller sees a Partial result, which includes the list of yielded values so far and a continuation. By calling the continuation with more data, the parser continues, none the wiser.

Take the following example

 testParse = do
   a <- getWord16be
   b <- getWord16be
   return $ a + b

 test = runGet testParse $ B.pack [1,0,0]

Here testParse needs to read 4 bytes in order to complete, so test is a Partial, which includes the continuation function, so which you can pass more data until it completes

The lookahead functions have been removed from this parser because of their incompatibility with the incremental monad at the moment.


The Get type

data Get r a Source


data Result a Source

The result of a partial parse


Failed String

the parse failed with the given error message

Finished ByteString a

the parse finished and produced the given list of results doing so. Any unparsed data is returned.

Partial (ByteString -> Result a)

the parse ran out of data before finishing, but produced the given list of results before doing so. To continue the parse pass more data to the given continuation


Show a => Show (Result a) 

runGet :: Get r r -> ByteString -> Result rSource

Start a parser and return the first Result.


skip :: Int -> Get r ()Source

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

bytesRead :: Get r IntSource

Get the total number of bytes read to this point.

remaining :: Get r IntSource

Get the number of remaining unparsed bytes. Useful for checking whether all input has been consumed.

isEmpty :: Get r BoolSource

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

plus :: Get r a -> Get r a -> Get r aSource

This is the choice operator. If the first option fails, the second is tried. The failure of the first option must happen within this function otherwise rollback is not attempted.

suspend :: Get r ()Source

Yield a partial and get more data

Parsing particular types


getByteString :: Int -> Get r ByteStringSource

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

Big-endian reads

Little-endian reads

Host-endian, unaligned reads