1 unstable release
0.1.0 | Jul 16, 2020 |
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#17 in #heap-allocator
32KB
651 lines
no_alloc
Embedded friendly pointer types for
no_std
applications without heap allocators.
lib.rs
:
Embedded friendly pointer types for no_std
applications without heap
allocators.
Usage
no_alloc
can be used to create boxes for dynamically sized types without
heap allocation:
#![no_main]
#![no_std]
use core::any::Any;
use cortex_m_rt::entry;
use no_alloc::{boxed_s, BoxS};
#[entry]
fn main() -> ! {
let boxed: BoxS<dyn Any, [usize; 1]> = boxed_s!(0_isize);
assert_eq!(boxed.downcast_ref::<isize>(), Some(&0));
loop {
// Application logic
}
}
Compile-time assertions are made to ensure that pointers will always be backed by enough memory and have the correct alignment. The following will fail to compile:
use core::any::Any;
use no_alloc::BoxS;
let _impossible: BoxS<dyn Any, [usize; 0]> = boxed_s!(0_isize);
For more information, consult the documentation for BoxS::new
.
Dependencies
no_alloc
has no runtime dependencies.
heapless
can be optionally brought in to add support for boxes backed by
global memory pools by activating the pool
feature.
Features
-
coerce_unsized
This feature requires a nightly toolchain
Implements
CoerceUnsized
forBoxS
, circumventing the requirement for theboxed_s
macro:use core::any::Any; use no_alloc::BoxS; let boxed: BoxS<dyn Any, [usize; 1]> = BoxS::new(0_isize);
-
const_generics
This feature requires a nightly toolchain
Implements
Memory
for arrays of any aribtrary length, rather than a few select lengths. -
pool
Enables smart pointers allocated from a global memory pool. This will drag in
heapless
as a dependency.
Safety
Safety is paramount to no_alloc
.
It works on top of a lot of unsafe code, but the exposed APIs are 100% safe.
The crate is extensively tested, and these tests are run through Miri as part of the CI for the crate. Commits that fail the Miri stage cannot be merged to master and are forbidden from being released to crates.io.
Dependencies
~145KB