Struct wasmtime_environ::GcArrayLayout

pub struct GcArrayLayout {
    pub size: u32,
    pub align: u32,
    pub length_field_offset: u32,
    pub elems_offset: u32,
    pub elem_size: u32,
}

The layout of a GC-managed array.

This layout is only valid for use with the GC runtime that created it. It is not valid to use one GC runtime’s layout with another GC runtime, doing so is memory safe but will lead to general incorrectness like panics and wrong results.

All offsets are from the start of the object; that is, the size of the GC header (for example) is included in the offset.

All arrays are composed of the generic VMGcHeader, followed by collector-specific fields, followed by the contiguous array elements themselves. The array elements must be aligned to the element type’s natural alignment.

Fields

size: u32

The size of this array object, ignoring its elements.

align: u32

The alignment of this array.

length_field_offset: u32

The offset of the array’s length.

elems_offset: u32

The offset from where this array’s contiguous elements begin.

elem_size: u32

The size and natural alignment of each element in this array.

Implementations

impl GcArrayLayout

pub fn size_for_len(&self, len: u32) -> u32

Get the total size of this array for a given length of elements.

pub fn elem_offset(&self, i: u32, elem_size: u32) -> u32

Get the offset of the ith element in an array with this layout.

pub fn layout(&self, len: u32) -> Layout

Get a core::alloc::Layout for an array of this type with the given length.

Trait Implementations

impl Clone for GcArrayLayout

fn clone(&self) -> GcArrayLayout

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for GcArrayLayout

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

Formats the value using the given formatter.

impl From<GcArrayLayout> for GcLayout

fn from(layout: GcArrayLayout) -> Self

Converts to this type from the input type.