sel4_abstract_allocator/
lib.rs

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1//
2// Copyright 2023, Colias Group, LLC
3//
4// SPDX-License-Identifier: BSD-2-Clause
5//
6
7#![no_std]
8
9#[cfg(feature = "alloc")]
10extern crate alloc;
11
12use core::alloc::Layout;
13use core::fmt;
14use core::ops::Range;
15
16pub mod bump;
17
18#[cfg(feature = "alloc")]
19pub mod basic;
20
21#[cfg(feature = "alloc")]
22mod by_range;
23
24#[cfg(feature = "alloc")]
25pub use by_range::ByRange;
26
27// TODO consider using u64 instead of usize, or abstract
28
29pub trait AbstractAllocatorAllocation {
30    fn range(&self) -> Range<usize>;
31}
32
33pub trait AbstractAllocator {
34    type AllocationError: fmt::Debug;
35
36    type Allocation: AbstractAllocatorAllocation;
37
38    fn allocate(&mut self, layout: Layout) -> Result<Self::Allocation, Self::AllocationError>;
39
40    fn deallocate(&mut self, allocation: Self::Allocation);
41}
42
43// // //
44
45pub struct WithAlignmentBound<A> {
46    inner: A,
47    max_alignment: usize,
48}
49
50impl<A> WithAlignmentBound<A> {
51    pub const fn new(inner: A, max_alignment: usize) -> Self {
52        Self {
53            inner,
54            max_alignment,
55        }
56    }
57
58    pub const fn max_alignment(&self) -> usize {
59        self.max_alignment
60    }
61
62    #[must_use]
63    pub fn is_suitably_aligned(&self, region: *mut u8) -> bool {
64        region.cast::<()>().align_offset(self.max_alignment()) == 0
65    }
66}
67
68#[derive(Debug, Copy, Clone, Ord, PartialOrd, Eq, PartialEq, Hash)]
69pub enum WithAlignmentBoundAllocationError<E> {
70    InnerError(E),
71    AlignmentExceedsBound,
72}
73
74impl<A: AbstractAllocator> AbstractAllocator for WithAlignmentBound<A> {
75    type AllocationError = WithAlignmentBoundAllocationError<A::AllocationError>;
76
77    type Allocation = A::Allocation;
78
79    fn allocate(&mut self, layout: Layout) -> Result<Self::Allocation, Self::AllocationError> {
80        if layout.align() > self.max_alignment() {
81            return Err(WithAlignmentBoundAllocationError::AlignmentExceedsBound);
82        }
83        self.inner
84            .allocate(layout)
85            .map_err(WithAlignmentBoundAllocationError::InnerError)
86    }
87
88    fn deallocate(&mut self, allocation: Self::Allocation) {
89        self.inner.deallocate(allocation)
90    }
91}
sel4_abstract_allocator/lib.rs

sel4_abstract_allocator/
lib.rs
