use core::num::Wrapping;
pub trait Encoding<T>: From<T> + Into<T>
where
Self: Copy,
{
const ZERO: Self;
}
macro_rules! define_endian {
($endian:ident) => {
#[derive(Clone, Copy)]
#[repr(transparent)]
pub struct $endian<T>(T);
};
}
macro_rules! impl_endian {
($endian:ident, $base:ident, $to_endian:ident, $from_endian:ident, $size:expr) => {
impl Encoding<$base> for $endian<$base> {
const ZERO: Self = Self(0);
}
impl From<[u8; $size]> for $endian<$base> {
#[inline]
fn from(bytes: [u8; $size]) -> Self {
Self($base::from_ne_bytes(bytes))
}
}
impl From<$endian<$base>> for [u8; $size] {
#[inline]
fn from(encoded: $endian<$base>) -> Self {
$base::to_ne_bytes(encoded.0)
}
}
impl From<$base> for $endian<$base> {
#[inline]
fn from(value: $base) -> Self {
Self($base::$to_endian(value))
}
}
impl From<Wrapping<$base>> for $endian<$base> {
#[inline]
fn from(Wrapping(value): Wrapping<$base>) -> Self {
Self($base::$to_endian(value))
}
}
impl From<$endian<$base>> for $base {
#[inline]
fn from($endian(value): $endian<$base>) -> Self {
$base::$from_endian(value)
}
}
};
}
define_endian!(BigEndian);
impl_endian!(BigEndian, u32, to_be, from_be, 4);
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_big_endian() {
let x = BigEndian::from(1u32);
assert_eq!(u32::from(x), 1);
}
}