Grouped Slotmap

grouped_slotmap.rs

#[derive(Clone, Debug)]
pub struct GroupedKey<K: Clone> {
    group_key: K,
    item_key: usize,
}
  
impl<K> GroupedKey<K> {
    fn new(group_key: K, item_key: usize) -> Self {
        Self {
            group_key,
            item_key
        }
    }
}

#[derive(Clone, Debug)]
pub struct GroupedSlotMap<K: Key, V: Clone, const BaseLen: usize = 8> {
    buf: HopSlotMap<K, SmallVec<[V; BaseLen]>>,
}

impl<K: Key, V: Clone, const BaseLen: usize> GroupedSlotMap<K, V, BaseLen> {
    pub fn insert_group(&mut self, items: &[V]) -> K {
        self.buf.insert(items.iter().cloned().collect())
    }

    pub fn insert(&mut self, item: V) -> K {
        self.buf.insert(vec![item].into())
    }
}

impl<K: Key, V: Clone, const BaseLen: usize> Index<K> for GroupedSlotMap<K, V, BaseLen> {
    type Output = SmallVec<[V; BaseLen]>;

    fn index(&self, index: K) -> &Self::Output {
        &self.buf[index]
    }
}

impl<K: Key, V: Clone, const BaseLen: usize> Index<GroupedKey<K>>
    for GroupedSlotMap<K, V, BaseLen>
{
    type Output = V;

    fn index(&self, index: GroupedKey<K>) -> &Self::Output {
        &self.buf[index.group_key][index.item_key]
    }
}