50 lines
1.3 KiB
Rust
50 lines
1.3 KiB
Rust
use hashbrown::HashMap;
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/// A set that automatically assigns a unique ID to every entry.
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///
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/// # How unique?
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///
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/// If you inserted a new entry every nanosecond, it would take more than
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/// 550_000 years to run out of indices. Realistically Orchid might insert a new
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/// entry every 10ms, so these 64-bit indices will probably outlast humanity.
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#[derive(Clone, Debug)]
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pub struct IdMap<T> {
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next_id: u64,
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data: HashMap<u64, T>,
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}
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impl<T> IdMap<T> {
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/// Create a new empty set
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pub fn new() -> Self { Self { next_id: 0, data: HashMap::new() } }
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/// Insert an element with a new ID and return the ID
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pub fn insert(&mut self, t: T) -> u64 {
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let id = self.next_id;
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self.next_id += 1;
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(self.data.try_insert(id, t)).unwrap_or_else(|_| panic!("IdMap keys should be unique"));
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id
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}
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/// Remove the element with the given ID from the set. The ID will not be
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/// reused.
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pub fn remove(&mut self, id: u64) -> Option<T> { self.data.remove(&id) }
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}
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impl<T> Default for IdMap<T> {
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fn default() -> Self { Self::new() }
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}
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#[cfg(test)]
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mod test {
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use super::IdMap;
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#[test]
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fn basic_test() {
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let mut map = IdMap::new();
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let a = map.insert(1);
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let b = map.insert(2);
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assert_eq!(map.remove(a), Some(1));
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assert_eq!(map.remove(a), None);
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assert_eq!(map.data.get(&b), Some(&2));
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}
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}
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