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use std::cmp;
use std::collections::hash_map::DefaultHasher;
use std::fmt;
use std::fmt::Display;
use std::hash::Hash;
use std::hash::Hasher;
use crate as gazebo;
use crate::dupe::Dupe;
#[derive(Dupe, Clone, Copy, PartialEq, Eq, Debug)]
pub struct Hashed<T> {
hash: u64,
value: T,
}
#[allow(clippy::derive_hash_xor_eq)]
impl<T> Hash for Hashed<T> {
fn hash<H: Hasher>(&self, state: &mut H) {
self.hash.hash(state)
}
}
impl<T: Display> Display for Hashed<T> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
self.value.fmt(f)
}
}
impl<T: PartialOrd> PartialOrd for Hashed<T> {
fn partial_cmp(&self, other: &Self) -> Option<cmp::Ordering> {
self.value.partial_cmp(&other.value)
}
}
impl<T: Ord> Ord for Hashed<T> {
fn cmp(&self, other: &Self) -> std::cmp::Ordering {
self.value.cmp(&other.value)
}
}
impl<T> AsRef<T> for Hashed<T> {
fn as_ref(&self) -> &T {
&self.value
}
}
impl<T> AsMut<T> for Hashed<T> {
fn as_mut(&mut self) -> &mut T {
&mut self.value
}
}
impl<T: Hash> From<T> for Hashed<T> {
fn from(value: T) -> Self {
Self::new(value)
}
}
impl<T: Hash> Hashed<T> {
pub fn new(value: T) -> Self {
let mut hasher = DefaultHasher::new();
value.hash(&mut hasher);
Self {
hash: hasher.finish(),
value,
}
}
pub fn into(self) -> T {
self.value
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_hashed() {
let v1 = Hashed::new("test");
let v2 = Hashed::from("test");
let v3 = Hashed::new("magic");
assert_eq!(v1, v2);
assert_ne!(v1, v3);
}
}