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//! The [`HandleSet`] type and associated definitions.
use crate::arena::{Arena, Handle, UniqueArena};
/// A set of `Handle<T>` values.
#[derive(Debug)]
pub struct HandleSet<T> {
/// Bound on indexes of handles stored in this set.
len: usize,
/// `members[i]` is true if the handle with index `i` is a member.
members: bit_set::BitSet,
/// This type is indexed by values of type `T`.
as_keys: std::marker::PhantomData<T>,
}
impl<T> HandleSet<T> {
/// Return a new, empty `HandleSet`.
pub fn new() -> Self {
Self {
len: 0,
members: bit_set::BitSet::new(),
as_keys: std::marker::PhantomData,
}
}
/// Return a new, empty `HandleSet`, sized to hold handles from `arena`.
pub fn for_arena(arena: &impl ArenaType<T>) -> Self {
let len = arena.len();
Self {
len,
members: bit_set::BitSet::with_capacity(len),
as_keys: std::marker::PhantomData,
}
}
/// Remove all members from `self`.
pub fn clear(&mut self) {
self.members.clear();
}
/// Remove all members from `self`, and reserve space to hold handles from `arena`.
pub fn clear_for_arena(&mut self, arena: &impl ArenaType<T>) {
self.members.clear();
self.members.reserve_len(arena.len());
}
/// Return an iterator over all handles that could be made members
/// of this set.
pub fn all_possible(&self) -> impl Iterator<Item = Handle<T>> {
super::Range::full_range_from_size(self.len)
}
/// Add `handle` to the set.
///
/// Return `true` if `handle` was not already present in the set.
pub fn insert(&mut self, handle: Handle<T>) -> bool {
self.members.insert(handle.index())
}
/// Remove `handle` from the set.
///
/// Returns `true` if `handle` was present in the set.
pub fn remove(&mut self, handle: Handle<T>) -> bool {
self.members.remove(handle.index())
}
/// Add handles from `iter` to the set.
pub fn insert_iter(&mut self, iter: impl IntoIterator<Item = Handle<T>>) {
for handle in iter {
self.insert(handle);
}
}
pub fn contains(&self, handle: Handle<T>) -> bool {
self.members.contains(handle.index())
}
/// Return an iterator over all handles in `self`.
pub fn iter(&self) -> impl '_ + Iterator<Item = Handle<T>> {
self.members.iter().map(Handle::from_usize)
}
}
impl<T> Default for HandleSet<T> {
fn default() -> Self {
Self::new()
}
}
pub trait ArenaType<T> {
fn len(&self) -> usize;
}
impl<T> ArenaType<T> for Arena<T> {
fn len(&self) -> usize {
self.len()
}
}
impl<T: std::hash::Hash + Eq> ArenaType<T> for UniqueArena<T> {
fn len(&self) -> usize {
self.len()
}
}