Struct AllocPrefix

#[repr(C)]
pub struct AllocPrefix<Alloc> {
    pub strong: AtomicUsize,
    pub weak: AtomicUsize,
    pub capacity: AtomicUsize,
    pub origin: NonNull<()>,
    pub alloc: MaybeUninit<Alloc>,
}

The prefix common to all allocations in stabby::alloc.

This allows reuse of allocations when converting between container types.

Fields

strong: AtomicUsize

The strong count for reference counted types.

weak: AtomicUsize

The weak count for reference counted types.

capacity: AtomicUsize

A slot to store a vector’s capacity when it’s turned into a boxed/arced slice.

origin: NonNull<()>

The origin of the prefix

alloc: MaybeUninit<Alloc>

A slot for the allocator.

Implementations

impl<Alloc> AllocPrefix<Alloc>

where Struct<FieldPair<FieldPair<FieldPair<FieldPair<AtomicUsize, AtomicUsize>, AtomicUsize>, NonNull<()>>, MaybeUninit<Alloc>>>: IStable, MaybeUninit<Alloc>: IStable, NonNull<()>: IStable, AtomicUsize: IStable,

pub const fn has_optimal_layout() -> bool

Returns true if the layout for AllocPrefix is smaller or equal to that Rust would have generated for it.

impl<Alloc> AllocPrefix<Alloc>

pub const fn skip_to<T>() -> usize

The offset between the prefix and a field of type T.

Trait Implementations

impl<Alloc> IStable for AllocPrefix<Alloc>

where Struct<FieldPair<FieldPair<FieldPair<FieldPair<AtomicUsize, AtomicUsize>, AtomicUsize>, NonNull<()>>, MaybeUninit<Alloc>>>: IStable, MaybeUninit<Alloc>: IStable, NonNull<()>: IStable, AtomicUsize: IStable,

const REPORT: &'static TypeReport

A compile-time generated report of the fields of the type, allowing for compatibility inspection.

const ID: u64

A stable (and ideally unique) identifier for the type. Often generated using crate::report::gen_id, but can be manually set.

type ForbiddenValues = <Struct<FieldPair<FieldPair<FieldPair<FieldPair<AtomicUsize, AtomicUsize>, AtomicUsize>, NonNull<()>>, MaybeUninit<Alloc>>> as IStable>::ForbiddenValues

The values that the annotated type cannot occupy.

type UnusedBits = <Struct<FieldPair<FieldPair<FieldPair<FieldPair<AtomicUsize, AtomicUsize>, AtomicUsize>, NonNull<()>>, MaybeUninit<Alloc>>> as IStable>::UnusedBits

The padding bits in the annotated types

type Size = <Struct<FieldPair<FieldPair<FieldPair<FieldPair<AtomicUsize, AtomicUsize>, AtomicUsize>, NonNull<()>>, MaybeUninit<Alloc>>> as IStable>::Size

The size of the annotated type in bytes.

type Align = <Struct<FieldPair<FieldPair<FieldPair<FieldPair<AtomicUsize, AtomicUsize>, AtomicUsize>, NonNull<()>>, MaybeUninit<Alloc>>> as IStable>::Align

The alignment of the annotated type in bytes.

type HasExactlyOneNiche = <Struct<FieldPair<FieldPair<FieldPair<FieldPair<AtomicUsize, AtomicUsize>, AtomicUsize>, NonNull<()>>, MaybeUninit<Alloc>>> as IStable>::HasExactlyOneNiche

Allows the detection of whether or not core::option::Options are stable:

type ContainsIndirections = <Struct<FieldPair<FieldPair<FieldPair<FieldPair<AtomicUsize, AtomicUsize>, AtomicUsize>, NonNull<()>>, MaybeUninit<Alloc>>> as IStable>::ContainsIndirections

Whether or not the type contains indirections (pointers, indices in independent data-structures…)

fn size() -> usize

Returns the size of the type.

fn align() -> usize

Returns the alignment of the type.

unsafe fn is_invalid(ptr: *const u8) -> bool

Returns true if ptr points to memory that cannot be a valid value of Self.