Struct RangeAllocator

Source

pub struct RangeAllocator<T> { /* private fields */ }

Expand description

A range allocator that manages allocation and deallocation of contiguous ranges.

The allocator starts with an initial range and maintains a list of free ranges. It uses a best-fit allocation strategy to minimize fragmentation when allocating new ranges.

§Type Parameters

T - The type used for range bounds. Must support arithmetic operations and ordering.

Implementations§

Source §

impl<T> RangeAllocator<T>
where T: Clone + Copy + Add<Output = T> + AddAssign + Sub<Output = T> + Eq + PartialOrd + Debug,

Source

pub fn new(range: Range<T>) -> Self

Creates a new range allocator with the specified initial range.

The entire initial range is marked as free and available for allocation.

§Arguments

range - The initial range that this allocator will manage.

§Example

use range_alloc_arceos::RangeAllocator;

let allocator = RangeAllocator::new(0..1024);

Source

pub fn initial_range(&self) -> &Range<T>

Returns a reference to the initial range managed by this allocator.

This is the range that was provided when the allocator was created, or the expanded range if grow_to was called.

Source

pub fn grow_to(&mut self, new_end: T)

Grows the allocator’s range to a new end point.

This extends the upper bound of the initial range and makes the new space available for allocation. If the last free range ends at the current upper bound, it is extended; otherwise, a new free range is added.

§Arguments

new_end - The new end point for the range (must be greater than the current end).

Source

pub fn allocate_range( &mut self, length: T, ) -> Result<Range<T>, RangeAllocationError<T>>

Allocates a contiguous range of the specified length.

This method uses a best-fit allocation strategy to find the smallest free range that can satisfy the request, minimizing fragmentation. If no single contiguous range is large enough, it returns an error with information about the total fragmented free space.

§Arguments

length - The length of the range to allocate.

§Returns

Ok(Range<T>) - The allocated range if successful.
Err(RangeAllocationError<T>) - If allocation fails, containing information about the total fragmented free space available.

§Example

use range_alloc_arceos::RangeAllocator;

let mut allocator = RangeAllocator::new(0..100);
let range = allocator.allocate_range(20).unwrap();
assert_eq!(range, 0..20);

Source

pub fn free_range(&mut self, range: Range<T>)

Frees a previously allocated range, making it available for future allocations.

This method attempts to merge the freed range with adjacent free ranges to reduce fragmentation. The freed range must be within the initial range and must not be empty.

§Arguments

range - The range to free. Must be within the allocator’s initial range.

§Panics

Panics if the range is outside the initial range or if the range is empty (start >= end).

§Example

use range_alloc_arceos::RangeAllocator;

let mut allocator = RangeAllocator::new(0..100);
let range = allocator.allocate_range(20).unwrap();
allocator.free_range(range);

Source