[][align_constr] [][align_constr]

Alignment-constrained [newtype]

Newtype whose [alignment] is constrained not only by the inherent alignment requirements of the underlying type but also by the alignment requirements of the "alignment constraint archetype". Within this context, "alignment constraint archetype" AlignConstrArchetype is a type whose alignment constraint is imposed on the underlying type T to produce [AlignConstr<T, AlignConstrArchetype>][AlignConstr].

Notes

• "alignment constraint archetype" is a stipulative functional definition.
• [AlignConstr<T, AlignConstrArchetype>][AlignConstr] for some underlying type T and "alignment constraint archetype" AlignConstrArchetype can also be seen as a refinement type reified in the form of a parameterized [newtype].

Resources on alignment

• "Data Alignment", personal website of Song Ho Ahn - a professor in the Computer Science department at Sheridan College (Oakville) > Not so visually appealing yet incredibly well written article that explains not only what alignment is but also why it exists and where one might need to overalign data. > > Dmitrii Demenev
• "What is overalignment of execution regions and input sections?", Stack Overflow
• "Data Structure alignment", GeeksforGeeks
• "Type Layout", The Rust Referece

Example

```rust use alignconstr::{AlignConstr, nzst::ZST128};

let overalignedu8 = AlignConstr::::new(3); assert!(overalignedu8.value == 3); // requires non-const context assert!(&overaligned_u8 as *const _ as usize % 128 == 0); ```

[align_constr] vs [aligned]

[aligned] is a popular library that served as a prototype for [align_constr]. At the time of writing, [align_constr] is featurewise and idiomatically superior and provides not only more extensive documentation but also a selection of resources on the subject. To pay respect to the contributors of [aligned] crate, the quality of their creation's [CI] is still unmatched by [align_constr]. However, the limited [scope] of both libraries nonetheless makes [align_constr] arguably better for any use case.

Note: Unlike in [aligned], the dependency on as_slice is optional.

About [align_constr]

• #[no_std] friendly
• Nightly-aware: the library offers opt-in support for nightly features. The names of almost all offered feature flags coincide with the names of the corresponding features from The Unstable Book.

License

<sup>Licensed under either of Apache License, Version 2.0 or MIT license at your option.</sup>

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