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use std::marker::PhantomData;
use crate::Idx;
#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub struct ArenaMap<IDX, V> {
v: Vec<Option<V>>,
_ty: PhantomData<IDX>,
}
impl<T, V> ArenaMap<Idx<T>, V> {
pub const fn new() -> Self {
Self { v: Vec::new(), _ty: PhantomData }
}
pub fn with_capacity(capacity: usize) -> Self {
Self { v: Vec::with_capacity(capacity), _ty: PhantomData }
}
pub fn reserve(&mut self, additional: usize) {
self.v.reserve(additional);
}
pub fn clear(&mut self) {
self.v.clear();
}
pub fn shrink_to_fit(&mut self) {
let min_len = self.v.iter().rposition(|slot| slot.is_some()).map_or(0, |i| i + 1);
self.v.truncate(min_len);
self.v.shrink_to_fit();
}
pub fn contains_idx(&self, idx: Idx<T>) -> bool {
matches!(self.v.get(Self::to_idx(idx)), Some(Some(_)))
}
pub fn remove(&mut self, idx: Idx<T>) -> Option<V> {
self.v.get_mut(Self::to_idx(idx))?.take()
}
pub fn insert(&mut self, idx: Idx<T>, t: V) -> Option<V> {
let idx = Self::to_idx(idx);
self.v.resize_with((idx + 1).max(self.v.len()), || None);
self.v[idx].replace(t)
}
pub fn get(&self, idx: Idx<T>) -> Option<&V> {
self.v.get(Self::to_idx(idx)).and_then(|it| it.as_ref())
}
pub fn get_mut(&mut self, idx: Idx<T>) -> Option<&mut V> {
self.v.get_mut(Self::to_idx(idx)).and_then(|it| it.as_mut())
}
pub fn values(&self) -> impl Iterator<Item = &V> {
self.v.iter().filter_map(|o| o.as_ref())
}
pub fn values_mut(&mut self) -> impl Iterator<Item = &mut V> {
self.v.iter_mut().filter_map(|o| o.as_mut())
}
pub fn iter(&self) -> impl Iterator<Item = (Idx<T>, &V)> {
self.v.iter().enumerate().filter_map(|(idx, o)| Some((Self::from_idx(idx), o.as_ref()?)))
}
pub fn iter_mut(&mut self) -> impl Iterator<Item = (Idx<T>, &mut V)> {
self.v
.iter_mut()
.enumerate()
.filter_map(|(idx, o)| Some((Self::from_idx(idx), o.as_mut()?)))
}
pub fn entry(&mut self, idx: Idx<T>) -> Entry<'_, Idx<T>, V> {
let idx = Self::to_idx(idx);
self.v.resize_with((idx + 1).max(self.v.len()), || None);
match &mut self.v[idx] {
slot @ Some(_) => Entry::Occupied(OccupiedEntry { slot, _ty: PhantomData }),
slot @ None => Entry::Vacant(VacantEntry { slot, _ty: PhantomData }),
}
}
fn to_idx(idx: Idx<T>) -> usize {
u32::from(idx.into_raw()) as usize
}
fn from_idx(idx: usize) -> Idx<T> {
Idx::from_raw((idx as u32).into())
}
}
impl<T, V> std::ops::Index<Idx<V>> for ArenaMap<Idx<V>, T> {
type Output = T;
fn index(&self, idx: Idx<V>) -> &T {
self.v[Self::to_idx(idx)].as_ref().unwrap()
}
}
impl<T, V> std::ops::IndexMut<Idx<V>> for ArenaMap<Idx<V>, T> {
fn index_mut(&mut self, idx: Idx<V>) -> &mut T {
self.v[Self::to_idx(idx)].as_mut().unwrap()
}
}
impl<T, V> Default for ArenaMap<Idx<V>, T> {
fn default() -> Self {
Self::new()
}
}
impl<T, V> Extend<(Idx<V>, T)> for ArenaMap<Idx<V>, T> {
fn extend<I: IntoIterator<Item = (Idx<V>, T)>>(&mut self, iter: I) {
iter.into_iter().for_each(move |(k, v)| {
self.insert(k, v);
});
}
}
impl<T, V> FromIterator<(Idx<V>, T)> for ArenaMap<Idx<V>, T> {
fn from_iter<I: IntoIterator<Item = (Idx<V>, T)>>(iter: I) -> Self {
let mut this = Self::new();
this.extend(iter);
this
}
}
pub enum Entry<'a, IDX, V> {
Vacant(VacantEntry<'a, IDX, V>),
Occupied(OccupiedEntry<'a, IDX, V>),
}
impl<'a, IDX, V> Entry<'a, IDX, V> {
pub fn or_insert(self, default: V) -> &'a mut V {
match self {
Self::Vacant(ent) => ent.insert(default),
Self::Occupied(ent) => ent.into_mut(),
}
}
pub fn or_insert_with<F: FnOnce() -> V>(self, default: F) -> &'a mut V {
match self {
Self::Vacant(ent) => ent.insert(default()),
Self::Occupied(ent) => ent.into_mut(),
}
}
pub fn and_modify<F: FnOnce(&mut V)>(mut self, f: F) -> Self {
if let Self::Occupied(ent) = &mut self {
f(ent.get_mut());
}
self
}
}
impl<'a, IDX, V> Entry<'a, IDX, V>
where
V: Default,
{
pub fn or_default(self) -> &'a mut V {
self.or_insert_with(Default::default)
}
}
pub struct VacantEntry<'a, IDX, V> {
slot: &'a mut Option<V>,
_ty: PhantomData<IDX>,
}
impl<'a, IDX, V> VacantEntry<'a, IDX, V> {
pub fn insert(self, value: V) -> &'a mut V {
self.slot.insert(value)
}
}
pub struct OccupiedEntry<'a, IDX, V> {
slot: &'a mut Option<V>,
_ty: PhantomData<IDX>,
}
impl<'a, IDX, V> OccupiedEntry<'a, IDX, V> {
pub fn get(&self) -> &V {
self.slot.as_ref().expect("Occupied")
}
pub fn get_mut(&mut self) -> &mut V {
self.slot.as_mut().expect("Occupied")
}
pub fn into_mut(self) -> &'a mut V {
self.slot.as_mut().expect("Occupied")
}
pub fn insert(&mut self, value: V) -> V {
self.slot.replace(value).expect("Occupied")
}
pub fn remove(self) -> V {
self.slot.take().expect("Occupied")
}
}