use core::cmp::Ordering;
use core::hash::{Hash, Hasher};
pub trait RefKey {
type Output;
fn key(&self) -> &Self::Output;
}
#[derive(Clone, Copy, Debug, Default)]
pub struct RefKeyed<T>(pub T);
impl<T> From<T> for RefKeyed<T> {
fn from(value: T) -> Self {
Self(value)
}
}
impl<T: RefKey> PartialEq for RefKeyed<T>
where
T::Output: PartialEq,
{
fn eq(&self, other: &Self) -> bool {
self.0.key().eq(other.0.key())
}
#[allow(clippy::partialeq_ne_impl)]
fn ne(&self, other: &Self) -> bool {
self.0.key().ne(other.0.key())
}
}
impl<T: RefKey> Eq for RefKeyed<T> where T::Output: Eq {}
impl<T: RefKey> PartialOrd for RefKeyed<T>
where
T::Output: PartialOrd,
{
fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
self.0.key().partial_cmp(other.0.key())
}
fn lt(&self, other: &Self) -> bool {
self.0.key().lt(other.0.key())
}
fn le(&self, other: &Self) -> bool {
self.0.key().le(other.0.key())
}
fn gt(&self, other: &Self) -> bool {
self.0.key().gt(other.0.key())
}
fn ge(&self, other: &Self) -> bool {
self.0.key().ge(other.0.key())
}
}
impl<T: RefKey> Ord for RefKeyed<T>
where
T::Output: Ord,
{
fn cmp(&self, other: &Self) -> Ordering {
self.0.key().cmp(other.0.key())
}
}
impl<T: RefKey> Hash for RefKeyed<T>
where
T::Output: Hash,
{
fn hash<H: Hasher>(&self, state: &mut H) {
self.0.key().hash(state)
}
}
#[cfg(test)]
mod tests {
use super::super::tests::{self, KeyValuePair};
use super::{RefKey, RefKeyed};
impl<K, V> RefKey for KeyValuePair<K, V> {
type Output = K;
fn key(&self) -> &Self::Output {
&self.key
}
}
#[test]
fn test_partial_eq() {
tests::test_partial_eq(RefKeyed);
}
#[test]
fn test_eq() {
tests::test_eq(RefKeyed);
}
#[test]
fn test_partial_ord() {
tests::test_partial_ord(RefKeyed);
}
#[test]
fn test_ord() {
tests::test_ord(RefKeyed);
}
#[test]
fn test_hash() {
tests::test_hash(RefKeyed);
}
}