Files
iris/core/src/util/slot.rs
T

116 lines
2.8 KiB
Rust

#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
pub struct SlotId {
idx: u32,
genr: u32,
}
impl SlotId {
pub(crate) fn slot(self) -> u32 {
self.idx
}
/// A stable, collision-free `u64` encoding of this id -- for a caller
/// (accesskit's `NodeId`, today) that wants a flat integer key rather
/// than the two `u32`s. `idx` is offset by one so no real id ever
/// encodes to 0, which callers can then reserve for their own
/// out-of-band root/window node.
pub fn as_u64(&self) -> u64 {
((self.idx as u64) + 1) << 32 | self.genr as u64
}
}
pub struct SlotVec<T> {
data: Vec<(u32, Option<T>)>,
free: Vec<u32>,
len: usize,
}
impl<T> SlotVec<T> {
pub fn new() -> Self {
Self {
data: Default::default(),
free: Default::default(),
len: 0,
}
}
pub fn add(&mut self, x: T) -> SlotId {
let id = if let Some(idx) = self.free.pop() {
let (genr, data) = &mut self.data[idx as usize];
*data = Some(x);
SlotId { idx, genr: *genr }
} else {
let idx = self.data.len() as u32;
let genr = 0;
self.data.push((genr, Some(x)));
SlotId { idx, genr }
};
self.len += 1;
id
}
pub fn free(&mut self, id: SlotId) {
let _ = self.remove(id);
}
pub fn remove(&mut self, id: SlotId) -> Option<T> {
self.remove_inner(id, true)
}
pub fn remove_unrecycled(&mut self, id: SlotId) -> Option<T> {
self.remove_inner(id, false)
}
fn remove_inner(&mut self, id: SlotId, recycle: bool) -> Option<T> {
let (genr, data) = &mut self.data[id.idx as usize];
if *genr != id.genr {
return None;
}
*genr += 1;
let value = data.take()?;
self.len -= 1;
if recycle {
self.free.push(id.idx);
}
Some(value)
}
pub fn get(&self, id: SlotId) -> Option<&T> {
let slot = &self.data[id.idx as usize];
if slot.0 != id.genr {
return None;
}
slot.1.as_ref()
}
pub fn get_mut(&mut self, id: SlotId) -> Option<&mut T> {
let slot = &mut self.data[id.idx as usize];
if slot.0 != id.genr {
return None;
}
slot.1.as_mut()
}
pub fn len(&self) -> usize {
self.len
}
pub fn is_empty(&self) -> bool {
self.len() == 0
}
pub fn values_mut(&mut self) -> impl Iterator<Item = &mut T> {
self.data.iter_mut().filter_map(|(_, value)| value.as_mut())
}
pub fn capacity(&self) -> usize {
self.data.len()
}
}
impl<T> Default for SlotVec<T> {
fn default() -> Self {
Self::new()
}
}