Struct plum::StandardBloomFilter

pub struct StandardBloomFilter<T: ?Sized> { /* fields omitted */ }

A fast standard Bloom Filter implementation that requires only two hash functions, generated by std::collections::hash_map::DefaultHasher.

If an item is not present in the filter then contains is guaranteed to return false for the queried item.

The probability that contains returns true for an item that is not present in the filter is called the False Positive Rate.

Example Usage

use plum::StandardBloomFilter;

let items_count = 1_000_000;
let fp_rate = 0.01;

let mut bloom = StandardBloomFilter::new(items_count, fp_rate);
bloom.insert("item1");
bloom.contains("item1"); /* true */
bloom.contains("item2"); /* false */

Implementations

impl<T: ?Sized> StandardBloomFilter<T>

pub fn new(items_count: usize, fp_rate: f64) -> Self

Create a new StandardBloomFilter that expects to store items_count membership with a false positive rate of the value specified in fp_rate.

pub fn insert(&mut self, item: &T) where
    T: Hash, 

Insert item to the set.

pub fn contains(&mut self, item: &T) -> bool where
    T: Hash, 

Check if an item is present in the set. There can be false positives, but no false negatives.