egui/util/
fixed_cache.rs

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1use epaint::util::hash;
2
3const FIXED_CACHE_SIZE: usize = 1024; // must be small for web/WASM build (for unknown reason)
4
5/// Very stupid/simple key-value cache. TODO(emilk): improve
6#[derive(Clone)]
7pub(crate) struct FixedCache<K, V>([Option<(K, V)>; FIXED_CACHE_SIZE]);
8
9impl<K, V> Default for FixedCache<K, V>
10where
11    K: Copy,
12    V: Copy,
13{
14    fn default() -> Self {
15        Self([None; FIXED_CACHE_SIZE])
16    }
17}
18
19impl<K, V> std::fmt::Debug for FixedCache<K, V> {
20    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
21        write!(f, "Cache")
22    }
23}
24
25impl<K, V> FixedCache<K, V>
26where
27    K: std::hash::Hash + PartialEq,
28{
29    pub fn get(&self, key: &K) -> Option<&V> {
30        let bucket = (hash(key) % (FIXED_CACHE_SIZE as u64)) as usize;
31        match &self.0[bucket] {
32            Some((k, v)) if k == key => Some(v),
33            _ => None,
34        }
35    }
36
37    pub fn set(&mut self, key: K, value: V) {
38        let bucket = (hash(&key) % (FIXED_CACHE_SIZE as u64)) as usize;
39        self.0[bucket] = Some((key, value));
40    }
41}
egui/util/fixed_cache.rs

egui/util/
fixed_cache.rs
