binary-strict-0.4.8: Binary deserialisation using strict ByteStrings

Portabilityportable to Hugs and GHC
MaintainerAdam Langley <>




Efficient construction of lazy bytestrings, bit by bit.


The Builder type

data BitBuilder Source

A BitBuilder is an efficient way to build lazy ByteStrings. There are several functions for constructing BitBuilders, but only one to inspect them: to extract any data, you have to turn them into lazy ByteStrings using toLazyByteString.

Internally, a BitBuilder constructs a lazy L.Bytestring by filling byte arrays piece by piece. As each buffer is filled, it is 'popped' off, to become a new chunk of the resulting lazy ByteString. All this is hidden from the user of the BitBuilder.

This is closely based on the Builder monad, but this one deals with single bits at a time.

toLazyByteString :: BitBuilder -> ByteStringSource

O(n). Extract a lazy ByteString from a BitBuilder. The construction work takes place if and when the relevant part of the lazy ByteString is demanded.

Constructing Builders

empty :: BitBuilderSource

O(1). The empty BitBuilder, satisfying

singleton :: Bool -> BitBuilderSource

O(1). A BitBuilder taking a single bit, satisfying

append :: BitBuilder -> BitBuilder -> BitBuilderSource

O(1). The concatenation of two BitBuilders, an associative operation with identity empty, satisfying

fromLazyByteString :: ByteString -> BitBuilderSource

O(1). A BitBuilder taking a lazy ByteString, satisfying

fromBits :: (Integral a, Bits a) => Int -> a -> BitBuilderSource

Construct a BitBuilder by taking the bottom n bits of a Bits instance. If the instance has less than n bits, this acts as if there was an infinite zero filled prefix

Flushing the buffer state

flush :: BitBuilderSource

O(1). Pop the ByteString we have constructed so far, if any, yielding a new chunk in the result lazy ByteString.