2 releases
0.1.1 | Feb 17, 2024 |
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0.1.0 | Jul 2, 2023 |
#232 in No standard library
26KB
360 lines
A #![no_std]
crate containing types for encapsulating unaligned values.
The primary type this crate provides is Unaligned<T>
, which stores a value of type T
unaligned.
Storing values unaligned can be an alternative to using #[repr(packed)]
structs (which can only be used
unsafely) or carefully-sized byte arrays. The Unaligned<T>
type exposes a safe mutable API for working
with unaligned values, while the companion type UnalignedCell<T>
is an interior mutability type that
provides a shared mutable API for working with unaligned values.
Because references are required to be aligned, it is unsafe to take a reference to a potentially unaligned value.
The Unaligned<T>
type therefore encapsulates the unaligned-ness of the value, letting code take (safe) references
to Unaligned<T>
. It also provides safe mutable APIs to set, replace, and access the value without taking an unaligned
reference.
Note that, in general, a safe shared API is not possible for unaligned values, because in order to do anything useful
with an unaligned value, the value must be moved into aligned storage - an inherently exclusive operation. The
UnalignedCell<T>
type somewhat alleviates this restriction by allowing exclusive access through a shared API
using the power of interior mutability.
This crate is #![no_std]
by default. The std
feature can be enabled to access functionality that requires the full
standard library.
Dependencies
~17KB