Spaces:
Build error
Build error
File size: 2,585 Bytes
84d2a97 |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 |
use std::cmp::{max, min};
use std::hash::{Hash, Hasher};
use common::types::{PointOffsetType, ScoreType};
use seahash::SeaHasher;
#[derive(Hash, Eq, PartialEq, Clone, Debug)]
struct PointPair {
a: PointOffsetType,
b: PointOffsetType,
}
impl PointPair {
pub fn new(a: PointOffsetType, b: PointOffsetType) -> Self {
PointPair {
a: min(a, b),
b: max(a, b),
}
}
}
#[derive(Clone, Debug)]
struct CacheObj {
points: PointPair,
value: ScoreType,
}
#[allow(dead_code)]
#[derive(Debug)]
pub struct DistanceCache {
cache: Vec<Option<CacheObj>>,
pub hits: usize,
pub misses: usize,
}
#[allow(dead_code)]
impl DistanceCache {
fn hasher() -> impl Hasher {
SeaHasher::new()
}
pub fn new(size: usize) -> Self {
let mut cache = Vec::with_capacity(size);
cache.resize(size, None);
DistanceCache {
cache,
hits: 0,
misses: 0,
}
}
pub fn get(&self, point_a: PointOffsetType, point_b: PointOffsetType) -> Option<ScoreType> {
let points = PointPair::new(point_a, point_b);
let mut s = DistanceCache::hasher();
points.hash(&mut s);
let idx = s.finish() as usize % self.cache.len();
self.cache[idx].as_ref().and_then(|x| {
if x.points == points {
Some(x.value)
} else {
None
}
})
}
pub fn put(&mut self, point_a: PointOffsetType, point_b: PointOffsetType, value: ScoreType) {
let points = PointPair::new(point_a, point_b);
let mut s = DistanceCache::hasher();
points.hash(&mut s);
let idx = s.finish() as usize % self.cache.len();
self.cache[idx] = Some(CacheObj { points, value });
}
}
impl Default for DistanceCache {
fn default() -> Self {
DistanceCache::new(0)
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_cache() {
let mut cache = DistanceCache::new(1000);
cache.put(100, 10, 0.8);
cache.put(10, 101, 0.7);
cache.put(10, 110, 0.1);
assert_eq!(cache.get(12, 99), None);
assert_eq!(cache.get(10, 100), Some(0.8));
assert_eq!(cache.get(10, 101), Some(0.7));
}
#[test]
fn test_collision() {
let mut cache = DistanceCache::new(1);
cache.put(1, 2, 0.8);
cache.put(3, 4, 0.7);
assert_eq!(cache.get(1, 2), None);
assert_eq!(cache.get(2, 1), None);
assert_eq!(cache.get(4, 3), Some(0.7));
}
}
|