Macro wnf::derive_from_zerocopy

macro_rules! derive_from_zerocopy {
    (AnyBitPattern for $type:ty) => { ... };
    (CheckedBitPattern for $type:ty) => { ... };
    (NoUninit for $type:ty) => { ... };
    ($trait:ident for $type:ty) => { ... };
}

Available on crate feature zerocopy only.

Macro for deriving wnf traits from zerocopy traits

Note that there cannot be a blanket implementation of wnf traits such as AnyBitPattern from zerocopy traits such as zerocopy::FromBytes. As zerocopy is an optional dependency of wnf, such a blanket implementation would have to be behind a feature gate just like any other zerocopy-related functionality of wnf. However, adding a blanket implementation is a breaking change and due to the way the Cargo feature resolver works, enabling a feature must not introduce a breaking change.

This macro provides an alternative to a blanket implementation by requiring you to explicitly opt in to the implementation.

If you have a type that implements zerocopy::FromBytes or zerocopy::AsBytes, you can derive the corresponding wnf traits as follows:

use wnf::derive_from_zerocopy;

#[derive(zerocopy::FromBytes, Copy, Clone)]
#[repr(C)]
struct Foo(u8, u16);

derive_from_zerocopy!(AnyBitPattern for Foo);

#[derive(zerocopy::AsBytes, Copy, Clone)]
#[repr(C)]
struct Bar(bool);

derive_from_zerocopy!(NoUninit for Bar);