RustCrypto: Hybrid Const Generic / Typenum Arrays

Hybrid array type combining const generics with the expressiveness of typenum-based constraints, providing an alternative to generic-array and a incremental transition path to const generics.

About

This crate uses typenum to enable the following features which aren't yet possible with the stable implementation of const generics:

• #60551: Associated constants in traits can not be used in const generics
• #76560: Complex generic constants: feature(generic_const_exprs)

Internally the crate is built on const generics and provides traits which make it possible to convert between const generic types and typenum types.

Features

This crate exposes the following feature flags. The default is NO features.

• zeroize - Implements Zeroize for Array<T: Zeroize, U>

Migrating from GenericArray

NOTE: this guide assumes a migration from generic-array v0.14

hybrid-array has been designed to largely be a drop-in replacement for generic-array, albeit with a public inner array type and significantly less unsafe code.

Migrating should hopefully be relatively painless with the following substitutions in your .rs files:

• Replace generic_array with hybrid_array
• Replace GenericArray<T, U> with Array<T, U>
• Replace ArrayLength<T> with ArraySize
• Replace <U as ArrayLength<T>>::ArrayType with <U as ArraySize>::ArrayType<T>
• Replace usages of the arr![N; A, B, C] macro with Array([A, B, C])

If you have any questions, please start a discussion.

License

Licensed under either of:

• Apache License, Version 2.0
• MIT license

at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.