Struct Field 

pub struct Field {
    pub name: Option<Symbol>,
    pub ty: TypeId,
    pub offset: u64,
    pub bit: u32,
    pub bits: Option<u32>,
}

One member of a record, placed.

Fields

name: Option<Symbol>

The member name, absent for an unnamed bit-field or an anonymous member.

ty: TypeId

The member type.

offset: u64

Where the member starts, in bytes from the start of the record, rounded down.

For an ordinary member this is exactly where it starts. For a bit-field it is the byte the first of its bits lives in, which is a starting point for a load rather than an address the program may take.

Bytes and not bits, with Field::bit holding the rest. A record may be PTRDIFF_MAX bytes and that many bits is more than a u64 holds, so a single bit offset would make the largest record this compiler can lay out an eighth of the largest one C allows.

bit: u32

Which bit of that byte the member starts at, from zero to seven.

Always zero for an ordinary member, since every one of those starts on a byte boundary.

bits: Option<u32>

The bit-field width, absent when the member is an ordinary one.

Implementations

impl Field

pub fn bit_offset(&self) -> u128

Where the member starts, in bits from the start of the record.

A u128 for the reason Field::offset is bytes. Nothing that generates code wants this number, which is why it is not what is stored: it is here because the layout rules were measured in bits and the tests that check them read in bits.

pub fn is_bit_field(&self) -> bool

Whether the member is a bit-field, zero width included.

Trait Implementations

impl Clone for Field

fn clone(&self) -> Field

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for Field

impl Debug for Field

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

Formats the value using the given formatter.

impl Eq for Field

impl PartialEq for Field

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for Field