Trait TowerLevel

pub trait TowerLevel<T>
where
    T: Default + Copy,
{
    type Data: AsMut<[T]> + AsRef<[T]> + Sized + Index<usize, Output = T> + IndexMut<usize, Output = T>;
    type Base: TowerLevel<T>;

    const WIDTH: usize;

    // Required methods
    fn split(
        data: &Self::Data,
    ) -> (&<Self::Base as TowerLevel<T>>::Data, &<Self::Base as TowerLevel<T>>::Data);
    fn split_mut(
        data: &mut Self::Data,
    ) -> (&mut <Self::Base as TowerLevel<T>>::Data, &mut <Self::Base as TowerLevel<T>>::Data);
    fn join(
        first: &<Self::Base as TowerLevel<T>>::Data,
        second: &<Self::Base as TowerLevel<T>>::Data,
    ) -> Self::Data;
    fn from_fn(f: impl Fn(usize) -> T) -> Self::Data;

    // Provided method
    fn default() -> Self::Data { ... }
}

Public API for recursive algorithms over data represented as an array of its limbs E.g. an F_{2^128} element expressed as 8 chunks of 2 bytes or a 256-bit integer represented as 32 individual bytes

Join and split can be used to combine and split underlying data into upper and lower halves

This is mostly useful for recursively implementing arithmetic operations

These separate implementations are necessary to overcome the limitations of const generics in Rust. These implementations eliminate costly bounds checking that would otherwise be imposed by the compiler and allow easy inlining of recursive functions.

Required Associated Constants

const WIDTH: usize

Required Associated Types

type Data: AsMut<[T]> + AsRef<[T]> + Sized + Index<usize, Output = T> + IndexMut<usize, Output = T>

type Base: TowerLevel<T>

Required Methods

fn split( data: &Self::Data, ) -> (&<Self::Base as TowerLevel<T>>::Data, &<Self::Base as TowerLevel<T>>::Data)

fn split_mut( data: &mut Self::Data, ) -> (&mut <Self::Base as TowerLevel<T>>::Data, &mut <Self::Base as TowerLevel<T>>::Data)

fn join( first: &<Self::Base as TowerLevel<T>>::Data, second: &<Self::Base as TowerLevel<T>>::Data, ) -> Self::Data

fn from_fn(f: impl Fn(usize) -> T) -> Self::Data

Provided Methods

fn default() -> Self::Data

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors

impl<T> TowerLevel<T> for TowerLevel1

where T: Default + Copy,

const WIDTH: usize = 1usize

type Data = [T; 1]

type Base = TowerLevel1

impl<T> TowerLevel<T> for TowerLevel2

where T: Default + Copy,

const WIDTH: usize = 2usize

type Data = [T; 2]

type Base = TowerLevel1

impl<T> TowerLevel<T> for TowerLevel4

where T: Default + Copy,

const WIDTH: usize = 4usize

type Data = [T; 4]

type Base = TowerLevel2

impl<T> TowerLevel<T> for TowerLevel8

where T: Default + Copy,

const WIDTH: usize = 8usize

type Data = [T; 8]

type Base = TowerLevel4

impl<T> TowerLevel<T> for TowerLevel16

where T: Default + Copy,

const WIDTH: usize = 16usize

type Data = [T; 16]

type Base = TowerLevel8

impl<T> TowerLevel<T> for TowerLevel32

where T: Default + Copy,

const WIDTH: usize = 32usize

type Data = [T; 32]

type Base = TowerLevel16

impl<T> TowerLevel<T> for TowerLevel64

where T: Default + Copy,

const WIDTH: usize = 64usize

type Data = [T; 64]

type Base = TowerLevel32