# Halfling
A library of basic utilities for working with [nibbles](https://en.wikipedia.org/wiki/Nibble), representing both raw data (`halfling::nibble::Nibble`) and integral values (`halfling::integer::{I4, U4}`).
Typical usage of this crate would be to reexport one of these principal types as part of a public API, though we encourage wrapping these in newtypes while `halfling` is still pre-v1.0.0; in particular the [delegate](https://crates.io/crates/delegate) crate is useful for this purpose.
## Performance
The principal types `Nibble`, `I4`, and `U4` should operate as (almost) zero-cost wrappers over the integral-byte types `u8` and `i8`, and egregious outliers are considered bugs; we encourage you to file an issue if you see this behaviour!
The notable exception is bitwise operations on `I4`s, since they're backed by `i8`s which first need to be transformed into a 4-bit two's complement representation; this compromise is based on the assumption that the integral types ought to focus on fast arithmetic operations.
## Roadmap
- `v0.2.0`
- Checked, saturating, and wrapping operation impls for `U4` and `I4`
- Bitshift operators for `U4` and `I4`
- `v0.3.0`
- Basic `PackedNibbleVec` implementation
- `FromIterator` and `IntoIterator` impls on `PackedNibbleVec`
- SIMD decoding? Probably requires profiling