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use std::collections::hash_map::DefaultHasher;
use std::hash::{Hash, Hasher};
use std::marker::PhantomData;
#[cfg(test)]
mod tests;
pub struct UnorderedHasher<T = DefaultHasher> {
hash: u64,
_marker: PhantomData<*const T>,
}
impl UnorderedHasher {
pub fn finish(&self) -> u64 {
self.hash
}
}
impl<T: Hasher + Default> UnorderedHasher<T> {
pub fn new() -> Self {
Self {
hash: 0,
_marker: PhantomData,
}
}
pub fn write<H: Hash>(&mut self, value: &H) {
let mut hasher = T::default();
value.hash(&mut hasher);
self.hash = self.hash.wrapping_add(hasher.finish());
}
}
impl Default for UnorderedHasher {
fn default() -> Self {
Self::new()
}
}
pub fn unordered_hash<T: Hash>(values: impl Iterator<Item = T>) -> u64 {
let mut hash = 0;
for value in values {
let mut hasher = DefaultHasher::default();
value.hash(&mut hasher);
hash = hasher.finish().wrapping_add(hash);
}
hash
}