endio_bit

Bit-level reading and writing

std::io::{Read, Write} only allow reading and writing on the byte-level. This is not sufficient when working with protocols that use single bits or use structs that are not multiples of 8 bits in size. This crate provides wrappers for reading and writing, enabling bit-level I/O on any object implementing [Read]/[Write].

The wrappers are modeled after [std::io::BufReader] and [std::io::BufWriter], so the semantics and interface should be familiar and robust.

This crate is a minimal low-level abstraction focusing on bit-level I/O. I recommend using this crate together with [endio] if you also need byte-level I/O or (de-)serialization support. However, this crate is completely independent from [endio], and can be used standalone if you're only looking for std::io with bit support.

Goals of this crate

• Reading and writing of single bits.
• Reading and writing of bits that aren't a multiple of 8.
• Reading and writing even if the underlying object is bitshifted.
• Support for bit endianness conversion/distinction.

Non-goals of this crate

• Data type (de-)serialization. If you need this, use [endio] in combination with this crate.
• Byte endianness conversion/distinction. If you need this, use [endio] in combination with this crate.

Comparison with other crates

Bit-level I/O is a common problem, and there are numerous crates on crates.io attempting to provide solutions. However, I haven't been able to find one that is completely satisfactory. Here's a list of related crates and how they differ from this one:

• av-bitstream - Includes (de-)serialization and byte endianness. No bit-level writing. Undocumented.

• bit-io - Does not implement std::io::{Read, Write}. No support for bit endianness. Undocumented.

• bitio - No support for writing. No support for bit endianness.

• bitstream, bitstream_reader, bitter - Include (de-)serialization and byte endianness. No support for writing.

• bitstream-io - Includes (de-)serialization and byte endianness. Includes Huffman trees for some reason. Does not implement std::io::{Read, Write}.

• bitstream-rs - Only has support for reading and writing single bits. Does not implement std::io::{Read, Write}.

• bitreader - Only has support for reading. Includes deserialization in forced big endian, no little endian support.

Therefore there is an opportunity to improve on the current library situation, which I hope to address through this crate.