indexlist.rs

#[derive(Debug)]
pub struct IndexList<T> {
    contents: Vec<Entry<T>>,
    generation: usize,
    next_free: Option<usize>,
    head: Option<usize>,
    tail: Option<usize>,
}

#[derive(Debug, PartialEq)]
pub enum Entry<T> {
    Free { next_free: Option<usize> },
    Occupied(OccupiedEntry<T>),
}

#[derive(Debug, PartialEq)]
pub struct OccupiedEntry<T> {
    item: T,
    generation: usize,
    next: Option<usize>,
    prev: Option<usize>,
}