74 lines
1.9 KiB
Rust
74 lines
1.9 KiB
Rust
//! A map from arena IDs to some other type. Space requirement is O(highest ID).
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use std::marker::PhantomData;
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use super::ArenaId;
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/// A map from arena IDs to some other type. Space requirement is O(highest ID).
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#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
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pub struct ArenaMap<ID, T> {
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v: Vec<Option<T>>,
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_ty: PhantomData<ID>,
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}
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impl<ID: ArenaId, T> ArenaMap<ID, T> {
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pub fn insert(&mut self, id: ID, t: T) {
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let idx = Self::to_idx(id);
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if self.v.capacity() <= idx {
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self.v.reserve(idx + 1 - self.v.capacity());
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}
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if self.v.len() <= idx {
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while self.v.len() <= idx {
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self.v.push(None);
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}
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}
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self.v[idx] = Some(t);
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}
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pub fn get(&self, id: ID) -> Option<&T> {
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self.v.get(Self::to_idx(id)).and_then(|it| it.as_ref())
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}
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pub fn get_mut(&mut self, id: ID) -> Option<&mut T> {
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self.v.get_mut(Self::to_idx(id)).and_then(|it| it.as_mut())
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}
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pub fn values(&self) -> impl Iterator<Item = &T> {
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self.v.iter().filter_map(|o| o.as_ref())
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}
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pub fn values_mut(&mut self) -> impl Iterator<Item = &mut T> {
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self.v.iter_mut().filter_map(|o| o.as_mut())
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}
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pub fn iter(&self) -> impl Iterator<Item = (ID, &T)> {
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self.v
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.iter()
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.enumerate()
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.filter_map(|(idx, o)| Some((Self::from_idx(idx), o.as_ref()?)))
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}
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fn to_idx(id: ID) -> usize {
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u32::from(id.into_raw()) as usize
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}
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fn from_idx(idx: usize) -> ID {
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ID::from_raw((idx as u32).into())
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}
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}
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impl<ID: ArenaId, T> std::ops::Index<ID> for ArenaMap<ID, T> {
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type Output = T;
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fn index(&self, id: ID) -> &T {
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self.v[Self::to_idx(id)].as_ref().unwrap()
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}
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}
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impl<ID, T> Default for ArenaMap<ID, T> {
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fn default() -> Self {
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ArenaMap {
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v: Vec::new(),
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_ty: PhantomData,
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}
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}
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}
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