Struct simple_chunk_allocator::ChunkAllocator

pub struct ChunkAllocator<'a, const CHUNK_SIZE: usize = DEFAULT_CHUNK_SIZE> { /* private fields */ }

Low-level chunk allocator that operates on the provided backing memory. Allocates memory with a variant of the strategies next-fit and best-fit.

The default chunk size is DEFAULT_CHUNK_SIZE. A large chunk size has the negative impact that small allocations will consume at least one chunk. A small chunk size has the negative impact that the allocation may take slightly longer.

Implementations

impl<'a, const CHUNK_SIZE: usize> ChunkAllocator<'a, CHUNK_SIZE>

pub const fn chunk_size(&self) -> usize

Returns the used chunk size.

pub const fn min_alignment(&self) -> usize

Returns the minimum guaranteed alignment by the allocator per chunk. A chunk will never be at an address like 0x13, i.e., unaligned.

pub const fn new(
    heap: &'a mut [u8],
    bitmap: &'a mut [u8]
) -> Result<Self, ChunkAllocatorError>

Creates a new allocator object. Verifies that the provided memory has the correct properties. Zeroes the bitmap.

• heap length must be a multiple of CHUNK_SIZE
• the heap must be not empty
• the bitmap must match the number of chunks
• the heap must be at least aligned to CHUNK_SIZE.

It is recommended that the heap and the bitmap both start at page-aligned addresses for better performance and to enable a faster search for correctly aligned addresses.

WARNING: During const initialization it is not possible to check the alignment of the provided buffer. Please make sure that the data is at least aligned to the chunk_size. The recommended alignment is page-alignment.

pub const fn new_const(heap: &'a mut [u8], bitmap: &'a mut [u8]) -> Self

Version of Self::new that panics instead of returning a result. Useful for globally static const contexts. The panic will happen during compile time and not during run time. Self::new can’t be used in such scenarios because unwrap() on the Result is not a const function (yet).

WARNING: During const initialization it is not possible to check the alignment of the provided buffer. Please make sure that the data is at least aligned to the chunk_size. The recommended alignment is page-alignment.

pub const fn capacity(&self) -> usize

Capacity in bytes of the allocator.

pub const fn chunk_count(&self) -> usize

Returns number of chunks.

pub fn usage(&self) -> f32

Returns the current memory usage in percentage rounded to two decimal places.

pub fn allocate(
    &mut self,
    layout: Layout
) -> Result<NonNull<[u8]>, ChunkAllocatorError>

pub unsafe fn deallocate(&mut self, ptr: NonNull<u8>, layout: Layout)

Safety

Unsafe if memory gets de-allocated that is still in use.

Trait Implementations

impl<'a, const CHUNK_SIZE: usize> Debug for ChunkAllocator<'a, CHUNK_SIZE>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.