use std::collections::HashMap;
use std::hash::Hash;
#[derive(Debug, Clone, PartialEq)]
pub struct OrderedMap<K: Eq + Hash, V> {
map: HashMap<K, V>,
keys: Vec<K>,
}
impl<K, V> OrderedMap<K, V> where K: Eq + Hash + Clone {
pub fn new() -> Self {
OrderedMap {
map: HashMap::new(),
keys: Vec::new(),
}
}
pub fn insert(&mut self, key: K, value: V) -> Option<V> {
if self.map.contains_key(&key) {
self.map.insert(key.clone(), value)
} else {
self.keys.push(key.clone());
self.map.insert(key, value)
}
}
pub fn contains_key(&self, key: &K) -> bool {
self.map.contains_key(key)
}
pub fn remove(&mut self, key: &K) -> Option<V> {
if let Some(value) = self.map.remove(key) {
self.keys.retain(|k| k != key);
Some(value)
} else {
None
}
}
pub fn get(&self, key: &K) -> Option<&V> {
self.map.get(key)
}
pub fn get_mut(&mut self, key: &K) -> Option<&mut V> {
self.map.get_mut(key)
}
pub fn iter(&self) -> impl Iterator<Item = (&K, &V)> {
self.keys.iter().filter_map(move |key| {
let value = self.map.get(key)?;
Some((key, value))
})
}
pub fn keys(&self) -> &Vec<K> {
&self.keys
}
pub fn len(&self) -> usize {
self.map.len()
}
pub fn is_empty(&self) -> bool {
self.map.is_empty()
}
}