Trait FixedOrderableBytes 

pub trait FixedOrderableBytes: OrderableBytes {
    type Array: AsRef<[u8]> + Copy;

    const ENCODED_LEN: usize;

    // Required method
    fn to_fixed_orderable_bytes(&self) -> Self::Array;
}

An OrderableBytes encoding whose length is the same for every value of the type.

to_fixed_orderable_bytes returns the same bytes as to_orderable_bytes, as an owned Array of exactly ENCODED_LEN bytes that doesn’t borrow from the value. Generic code can store or return it:

use orderable_bytes::FixedOrderableBytes;

fn term<T: FixedOrderableBytes>(value: T) -> T::Array {
    value.to_fixed_orderable_bytes()
}

assert_eq!(term(7u32), [0, 0, 0, 7]);

Fixed-length encodings may be zero-extended to a larger block, since every value is extended the same way. Bounding on this trait is what keeps variable-length types out of such code:

use orderable_bytes::FixedOrderableBytes;

fn pad_to_16<T: FixedOrderableBytes>(value: &T) -> [u8; 16] {
    let mut block = [0u8; 16];
    block[..T::ENCODED_LEN].copy_from_slice(value.to_fixed_orderable_bytes().as_ref());
    block
}

assert!(pad_to_16(&1u32) < pad_to_16(&2u32));

// Strings are variable-length, so padding them is rejected.
pad_to_16(&String::from("a"));

Required Associated Constants

const ENCODED_LEN: usize

Length, in bytes, of the canonical encoding.

Required Associated Types

type Array: AsRef<[u8]> + Copy

The owned encoding: always [u8; ENCODED_LEN].

Required Methods

fn to_fixed_orderable_bytes(&self) -> Self::Array

Build the canonical, order-preserving byte encoding of self as an owned array. The bytes are the same as to_orderable_bytes returns.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementations on Foreign Types

impl FixedOrderableBytes for bool

const ENCODED_LEN: usize = 1

type Array = [u8; 1]

fn to_fixed_orderable_bytes(&self) -> [u8; 1]

impl FixedOrderableBytes for char

const ENCODED_LEN: usize = 4

type Array = [u8; 4]

fn to_fixed_orderable_bytes(&self) -> [u8; 4]

impl FixedOrderableBytes for f32

const ENCODED_LEN: usize = 4

type Array = [u8; 4]

fn to_fixed_orderable_bytes(&self) -> [u8; 4]

impl FixedOrderableBytes for f64

const ENCODED_LEN: usize = 8

type Array = [u8; 8]

fn to_fixed_orderable_bytes(&self) -> [u8; 8]

impl FixedOrderableBytes for i8

const ENCODED_LEN: usize = 1

type Array = [u8; 1]

fn to_fixed_orderable_bytes(&self) -> [u8; 1]

impl FixedOrderableBytes for i16

const ENCODED_LEN: usize = 2

type Array = [u8; 2]

fn to_fixed_orderable_bytes(&self) -> [u8; 2]

impl FixedOrderableBytes for i32

const ENCODED_LEN: usize = 4

type Array = [u8; 4]

fn to_fixed_orderable_bytes(&self) -> [u8; 4]

impl FixedOrderableBytes for i64

const ENCODED_LEN: usize = 8

type Array = [u8; 8]

fn to_fixed_orderable_bytes(&self) -> [u8; 8]

impl FixedOrderableBytes for i128

const ENCODED_LEN: usize = 16

type Array = [u8; 16]

fn to_fixed_orderable_bytes(&self) -> [u8; 16]

impl FixedOrderableBytes for u8

const ENCODED_LEN: usize = 1

type Array = [u8; 1]

fn to_fixed_orderable_bytes(&self) -> [u8; 1]

impl FixedOrderableBytes for u16

const ENCODED_LEN: usize = 2

type Array = [u8; 2]

fn to_fixed_orderable_bytes(&self) -> [u8; 2]

impl FixedOrderableBytes for u32

const ENCODED_LEN: usize = 4

type Array = [u8; 4]

fn to_fixed_orderable_bytes(&self) -> [u8; 4]

impl FixedOrderableBytes for u64

const ENCODED_LEN: usize = 8

type Array = [u8; 8]

fn to_fixed_orderable_bytes(&self) -> [u8; 8]

impl FixedOrderableBytes for u128

const ENCODED_LEN: usize = 16

type Array = [u8; 16]

fn to_fixed_orderable_bytes(&self) -> [u8; 16]

impl<T: FixedOrderableBytes + ?Sized> FixedOrderableBytes for &T

const ENCODED_LEN: usize = T::ENCODED_LEN

type Array = <T as FixedOrderableBytes>::Array

fn to_fixed_orderable_bytes(&self) -> T::Array

impl<const N: usize> FixedOrderableBytes for [u8; N]

const ENCODED_LEN: usize = N

type Array = [u8; N]

fn to_fixed_orderable_bytes(&self) -> [u8; N]

Implementors