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 std::io::Read/std::io::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 for a higher level of abstraction and ergonomics. 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.

Non-goals of this crate

• Any data type (de-)serialization. If you need this, use endio in combination with this crate.
• Any 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 endianness. The entire crate is undocumented.

• bit-io - Does not implement std::io::{Read, Write} on its abstractions, thus not being suitable for code requiring these traits.

• bitio - Only has support for reading.

• bitstream, bitstream_reader, bitter - Only have support for reading. Include deserialization and endianness instead of being a low-level abstraction.

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

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

• 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.