bendns' repos / rust-analyzer
Unnamed repository; edit this file 'description' to name the repository.
Diffstat (limited to 'lib/la-arena/src/map.rs')
-rw-r--r--lib/la-arena/src/map.rs75
1 files changed, 75 insertions, 0 deletions
diff --git a/lib/la-arena/src/map.rs b/lib/la-arena/src/map.rs
new file mode 100644
index 0000000000..d27f086d37
--- /dev/null
+++ b/lib/la-arena/src/map.rs
@@ -0,0 +1,75 @@
+use std::marker::PhantomData;
+
+use crate::Idx;
+
+/// A map from arena indexes to some other type.
+/// Space requirement is O(highest index).
+#[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> {
+ /// Inserts a value associated with a given arena index into the map.
+ pub fn insert(&mut self, idx: Idx<T>, t: V) {
+ let idx = Self::to_idx(idx);
+
+ self.v.resize_with((idx + 1).max(self.v.len()), || None);
+ self.v[idx] = Some(t);
+ }
+
+ /// Returns a reference to the value associated with the provided index
+ /// if it is present.
+ pub fn get(&self, idx: Idx<T>) -> Option<&V> {
+ self.v.get(Self::to_idx(idx)).and_then(|it| it.as_ref())
+ }
+
+ /// Returns a mutable reference to the value associated with the provided index
+ /// if it is present.
+ 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())
+ }
+
+ /// Returns an iterator over the values in the map.
+ pub fn values(&self) -> impl Iterator<Item = &V> {
+ self.v.iter().filter_map(|o| o.as_ref())
+ }
+
+ /// Returns an iterator over mutable references to the values in the map.
+ pub fn values_mut(&mut self) -> impl Iterator<Item = &mut V> {
+ self.v.iter_mut().filter_map(|o| o.as_mut())
+ }
+
+ /// Returns an iterator over the arena indexes and values in the map.
+ 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()?)))
+ }
+
+ 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 {
+ ArenaMap { v: Vec::new(), _ty: PhantomData }
+ }
+}