binary-strict-0.4.8.2: Binary deserialisation using strict ByteStrings

CopyrightLennart Kolmodin, Ross Paterson, Adam Langley
LicenseBSD3-style (see LICENSE)
MaintainerAdam Langley <agl@imperialviolet.org>
Stabilityexperimental
Portabilityportable to Hugs and GHC
Safe HaskellNone
LanguageHaskell98

Data.Binary.BitBuilder

Contents

Description

Efficient construction of lazy bytestrings, bit by bit.

Synopsis

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 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 -> ByteString Source

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 :: BitBuilder Source

O(1). The empty BitBuilder, satisfying

singleton :: Bool -> BitBuilder Source

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

append :: BitBuilder -> BitBuilder -> BitBuilder Source

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

fromLazyByteString :: ByteString -> BitBuilder Source

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

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

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 :: BitBuilder Source

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