Struct BitField

pub struct BitField<S, T, const POSITION: usize, const SIZE: usize, const SIGN_EXTEND: bool>(/* private fields */);

A bitfield descriptor type. Define an alias to this structure in order to use it properly.

Parameters

• S: Storage container for bitfield, must be larger or equal to SIZE.
• T: Type to store in a bitfield, must implement ToBitfield and FromBitfield traits, this allows us to also encode booleans and enums easily in bitfield.
• POSITION: position of bitfield in storage container, must not be out of bounds.
• SIZE: Size of the bitfield, note that if T is u32 and we set size to 16 then only 16 bits of the 32-bit value will be stored.
• SIGN_EXTEND: Whether or not to do sign-extension on decode operation.

Example usage

use easy_bitfield::*;
// simple boolean bitfield at position 0
pub type MyBitfield = BitField<usize, bool, 0, 1, false>;
// simple 17-bit bitfield that is encoded/decoded from u32, located at second bit
pub type OtherBitfield = BitField<usize, u32, { MyBitfield::NEXT_BIT }, 17, false>;

Trait Implementations

impl<S, T, const POSITION: usize, const SIZE: usize, const SIGN_EXTEND: bool> BitFieldTrait<S> for BitField<S, T, POSITION, SIZE, SIGN_EXTEND>

where S: ToPrimitive + FromPrimitive + One + PrimInt, T: FromBitfield<S> + ToBitfield<S> + PartialEq + Eq + Copy,

const NEXT_BIT: usize

Next bit after current bitfield, use this to not waste time calculating what the next bitfield position should be

type Type = T

Type we encode/decode in bitfield

fn mask() -> S

Mask of this bitfield

fn mask_in_place() -> S

In place mask of this bitfield

fn shift() -> usize

Shift of this bitfield

fn bitsize() -> usize

Bitsize of this bitifield

fn encode(value: T) -> S

Encodes value as bitfield

fn decode(value: S) -> T

Decodes bitfield into Type

fn update(value: T, original: S) -> S

Updates the value in storage original, returns updated storage

fn is_valid(value: T) -> bool

Checks if value is valid to encode.

fn encode_unchecked(value: T) -> S

Unchecked encode of value, all bits that can’t be encoded will be stripped down.