blob: 8eb7b7a00b9f96f5bc5b0a14ae9cc6b2e27a214c [file] [log] [blame]
use crate::sealed;
use core::num::Wrapping;
pub trait Encoding<T>: Copy + From<T> + Sized + sealed::Sealed
where
T: From<Self>,
{
const ZERO: Self;
}
pub fn as_bytes<E: Encoding<T>, T>(x: &[E]) -> &[u8]
where
T: From<E>,
{
unsafe {
core::slice::from_raw_parts(x.as_ptr() as *const u8, x.len() * core::mem::size_of::<E>())
}
}
macro_rules! define_endian {
($endian:ident) => {
#[repr(transparent)]
#[derive(Copy, Clone)]
pub struct $endian<T>(T)
where
T: Copy + Clone + Sized;
impl<T> sealed::Sealed for $endian<T> where T: Copy + Clone + Sized {}
};
}
macro_rules! impl_endian {
($endian:ident, $base:ident, $to_endian:ident, $from_endian:ident) => {
impl Encoding<$base> for $endian<$base> {
const ZERO: Self = $endian(0);
}
impl From<$base> for $endian<$base> {
#[inline]
fn from(value: $base) -> Self { $endian($base::$to_endian(value)) }
}
impl From<Wrapping<$base>> for $endian<$base> {
#[inline]
fn from(Wrapping(value): Wrapping<$base>) -> Self { $endian($base::$to_endian(value)) }
}
impl From<$endian<$base>> for $base {
#[inline]
fn from($endian(value): $endian<$base>) -> Self { $base::$from_endian(value) }
}
impl AsRef<[u8; core::mem::size_of::<Self>()]> for $endian<$base> {
fn as_ref(&self) -> &[u8; core::mem::size_of::<Self>()] {
unsafe { core::mem::transmute(self) }
}
}
};
}
define_endian!(BigEndian);
define_endian!(LittleEndian);
impl_endian!(BigEndian, u32, to_be, from_be);
impl_endian!(BigEndian, u64, to_be, from_be);
impl_endian!(LittleEndian, u32, to_le, from_le);
impl_endian!(LittleEndian, u64, to_le, from_le);
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_big_endian() {
let x = BigEndian::from(1u32);
assert_eq!(u32::from(x), 1);
}
}