growable-bloom-filter 0.2.2

Scalable Bloom Filters with serde support
Documentation

Table of Contents

  1. Growable Bloom Filters
    1. Overview
    2. Applications

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Growable Bloom Filters

CRATES.IO | DOCUMENTATION

Overview

Implementation of Scalable Bloom Filters which also provides serde serialization and deserialize.

A bloom filter lets you insert items, and then test association with contains. It's space and time efficient, at the cost of false positives. In particular, if contains returns true, it may be in filter. But if contains returns false, it's definitely not in the bloom filter.

You can control the failure rate by setting desired_error_prob and est_insertions appropriately.

use serde_json;
use growable_bloom_filter::GrowableBloom;

let mut gbloom = GrowableBloom::new(0.05, 1000);
gbloom.insert(&0);
assert!(gbloom.contains(&0));

let s = serde_json::to_string(&gbloom).unwrap();
let des_gbloom: GrowableBloom = serde_json::from_str(&s).unwrap();
assert!(des_gbloom.contains(&0));

Applications

Bloom filters are typically used as a pre-cache to avoid expensive operations. For example, if you need to ask ten thousand servers if they have data XYZ, you could use GrowableBloom to figure out which ones do NOT have XYZ.