Struct LinearAllocator

pub struct LinearAllocator { /* private fields */ }

LinearAllocator is an allocator that keeps a fixed-sized buffer internally and use it to make allocations. Once the buffer is full, all next allocations fails.

This allocator is useful when you want a “scratch space” for multiple tiny allocations that share the same lifetime.

Usage:

#![cfg_attr(not(feature = "stable"), feature(allocator_api))]
#[cfg(feature = "vec")]
{
    use core::mem::size_of;

    use piece::vec::Vec;
    use piece::LinearAllocator;

    let linear_allocator = LinearAllocator::with_capacity(64 * size_of::<i32>());

    let mut vec1 = Vec::with_capacity_in(32, &linear_allocator);
    let mut vec2 = Vec::with_capacity_in(32, &linear_allocator);

    vec1.extend_from_slice(&[1, 2, 3, 4, 5]);
    vec2.extend_from_slice(&[6, 7, 8, 9, 10]);

    assert_eq!(vec1, &[1, 2, 3, 4, 5]);
    assert_eq!(vec2, &[6, 7, 8, 9, 10]);
}

Implementations

impl LinearAllocator

pub fn with_capacity(capacity: usize) -> Self

Creates a new LinearAllocator with the specified capacity

PANIC: capacity must be greater than zero

pub fn allocated_bytes(&self) -> usize

Trait Implementations

impl Allocator for LinearAllocator

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

🔬This is a nightly-only experimental API. (allocator_api)

Attempts to allocate a block of memory.

unsafe fn deallocate(&self, _ptr: NonNull<u8>, _layout: Layout)

🔬This is a nightly-only experimental API. (allocator_api)

Deallocates the memory referenced by ptr.

fn allocate_zeroed(&self, layout: Layout) -> Result<NonNull<[u8]>, AllocError>

🔬This is a nightly-only experimental API. (allocator_api)

Behaves like allocate, but also ensures that the returned memory is zero-initialized.

unsafe fn grow( &self, ptr: NonNull<u8>, old_layout: Layout, new_layout: Layout, ) -> Result<NonNull<[u8]>, AllocError>

🔬This is a nightly-only experimental API. (allocator_api)

Attempts to extend the memory block.

unsafe fn grow_zeroed( &self, ptr: NonNull<u8>, old_layout: Layout, new_layout: Layout, ) -> Result<NonNull<[u8]>, AllocError>

🔬This is a nightly-only experimental API. (allocator_api)

Behaves like grow, but also ensures that the new contents are set to zero before being returned.

unsafe fn shrink( &self, ptr: NonNull<u8>, old_layout: Layout, new_layout: Layout, ) -> Result<NonNull<[u8]>, AllocError>

🔬This is a nightly-only experimental API. (allocator_api)

Attempts to shrink the memory block.

fn by_ref(&self) -> &Self

where Self: Sized,

🔬This is a nightly-only experimental API. (allocator_api)

Creates a “by reference” adapter for this instance of Allocator.

impl Drop for LinearAllocator

fn drop(&mut self)

Executes the destructor for this type.

impl Send for LinearAllocator

impl Sync for LinearAllocator