https://github.com/srinivasreddy/rust-bloomfilter

🦀 Bloom filter implementation in Rust 🦀
https://github.com/srinivasreddy/rust-bloomfilter

bloom-filter probabilistic-data-structures rust

Last synced: 2 months ago
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🦀 Bloom filter implementation in Rust 🦀

• Host: GitHub
• URL: https://github.com/srinivasreddy/rust-bloomfilter
• Owner: srinivasreddy
• License: mit
• Created: 2019-10-18T09:23:48.000Z (over 5 years ago)
• Default Branch: master
• Last Pushed: 2020-11-18T05:47:38.000Z (about 4 years ago)
• Last Synced: 2024-11-28T11:16:31.190Z (3 months ago)
• Topics: bloom-filter, probabilistic-data-structures, rust
• Language: Rust
• Homepage:
• Size: 17.6 KB
• Stars: 18
• Watchers: 3
• Forks: 1
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • Funding: .github/FUNDING.yml
  • License: LICENSE

Awesome Lists containing this project

README

        
## rust-bloomfilter

Bloom filters are defined by 4 interdependent values:

* n - Number of items in the filter

* p - Probability of false positives, float between 0 and 1 or a number indicating 1-in-p

* m - Number of bits in the filter

* k - Number of hash functions

## Guide for selecting the parameters

The values are interdependent as shown in the following calculations:

```

m = ceil((n * log(p)) / log(1.0 / (pow(2.0, log(2.0)))));

k = round(log(2.0) * m / n);

```

## Design

I use murmur3 hash to generate 128 bit hash integer, and then i split it into two integers of 64 bits each.

Following is the pseudo-code written for the design of bloom filter.

````

let hash_128 = murmur3_hash(data);

let first_64 = (hash_128 & (2_u128.pow(64) - 1));

let second_64 = hash >> 64;

for i 0..num_of_hashfuncs{

    first_64 += i* second_64;

    index =  fist_64 % number_of_bits

    self.bitvec.set(index, true);

}

````

## Usage

````rust

extern crate rust_bloomfilter;

use rust_bloomfilter::BloomFilter;

let mut b = BloomFilter(20000, 0.01, true);

b.add("Helloworld");

assert!(b.contains("Helloworld"));

````