Bloom Filter

Simple bloom filter implementation in Rust.

To use this crate in any Rust project just one of the following dependencies.

Install

yaml [dependencies] ... bfilters = { git = "https://github.com/alexanderbakhmach/bloom-filter", branch = "<desired-branch>", version = "<desired-version>"}

For example for dev branch with version 0.1.1 the dependecy will look the following.

yaml [dependencies] ... bfilters = { git = "https://github.com/alexanderbakhmach/bloom-filter", branch = "dev", version = "0.1.3"}

Or as a registered create yaml [dependencies] ... bfilters = "0.1.3"

Use

The example below illustrates the bloom filter usage.

```rust use bfilters::BloomFilter;

...

let itemscapacity: u32 = 933333; let falsepositiveprobability: f32 = 0.04;

let mut bloomfilter: BloomFilter = match BloomFilter::new(Some(falsepositiveprobability), itemscapacity) { Ok(bloomfilter) => bloomfilter, Err(msg) => panic!("Can not create bloom filter due to error: {}", msg), };

let itemtosave: &str = "Erc20Token"; let item_absent: &str = "Erc721Token";

bloomfilter.insert(itemto_save);

assert!(!bloomfilter.isprobablypresent(itemabsent)); ```

Also falsepositiveprobability could be None then it will be computed with a formula.

```rust use bfilters::BloomFilter;

...

let itemscapacity: u32 = 933333;

let mut bloomfilter: BloomFilter = match BloomFilter::new(None, itemscapacity) { Ok(bloomfilter) => bloomfilter, Err(msg) => panic!("Can not create bloom filter due to error: {}", msg), };

let itemtosave: &str = "Erc20Token"; let item_absent: &str = "Erc721Token";

bloomfilter.insert(itemto_save);

assert!(!bloomfilter.isprobablypresent(itemabsent)); ```

The bloom filter could be serialized and deserialized in the JSON format.

```rust use std::{fs, path::Path}; use bfilters::BloomFilter;

// Define the bloom filter state let testfalsepositiveprobability: f32 = 0.01; let testitemscount: u32 = 923578; let testcapacity: u32 = 923578 * 10; let testnumberof_hashes: u32 = 4;

// Define the bloom filter test items let testitem: &str = "Vinegar"; let testabsent_item: &str = "Coke";

// Instantiate a bloom filter let mut bloomfilter: BloomFilter = match BloomFilter::custom( testitemscount, Some(testfalsepositiveprobability), Some(testcapacity), Some(testnumberofhashes), ) { Ok(bloomfilter) => bloomfilter, Err(msg) => panic!("{}", msg), };

// Validate that the bloom filter is working bloomfilter.insert(testitem);

let probablypresent: bool = bloomfilter.isprobablypresent(testabsentitem);

asserteq!(probablypresent, false);

// Serializing bloom filter into test tmp file let tmpsavepath: &Path = std::path::Path::new("./bfilter_tmp.json");

bloomfilter.save(tmpsave_path).unwrap();

// Initialize a new bloom filter from the file let mut deserializedbloomfilter: BloomFilter = BloomFilter::fromfile(tmpsave_path).unwrap();

// Validating that the deserialized bloom filter is working as before let probablypresent: bool = deserializedbloomfilter.isprobablypresent(testabsent_item); ```

Docs

Rust provides you with a beautiful documentation autogeneration tool. To generate documentation in your browser simply run the following command from the root of this project.

bash cargo doc --no-deps --open