Enum FieldsShape

pub enum FieldsShape {
    Primitive,
    Union(NonZero<usize>),
    Array {
        stride: MachineSize,
        count: u64,
    },
    Arbitrary {
        offsets: Vec<MachineSize>,
    },
}

Describes how the fields of a type are shaped in memory.

Variants

Primitive

Scalar primitives and !, which never have fields.

Union(NonZero<usize>)

All fields start at no offset. The usize is the field count.

Array

Array/vector-like placement, with all fields of identical types.

Fields

stride: MachineSize

count: u64

Arbitrary

Struct-like placement, with precomputed offsets.

Fields are guaranteed to not overlap, but note that gaps before, between and after all the fields are NOT always padding, and as such their contents may not be discarded. For example, enum variants leave a gap at the start, where the discriminant field in the enum layout goes.

Fields

offsets: Vec<MachineSize>

Offsets for the first byte of each field, ordered to match the source definition order. I.e.: It follows the same order as crate::ty::VariantDef::fields(). This vector does not go in increasing order.

Implementations

impl FieldsShape

pub fn fields_by_offset_order(&self) -> Vec<FieldIdx>

pub fn count(&self) -> usize

Trait Implementations

impl Clone for FieldsShape

fn clone(&self) -> FieldsShape

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for FieldsShape

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

Formats the value using the given formatter.

impl Hash for FieldsShape

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for FieldsShape

fn eq(&self, other: &FieldsShape) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Serialize for FieldsShape

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl Eq for FieldsShape

impl StructuralPartialEq for FieldsShape

Layout

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.

Size: 24 bytes

Size for each variant:

• Primitive: 0 bytes
• Union: 16 bytes
• Array: 24 bytes
• Arbitrary: 24 bytes