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Elias-Fano, in Rust

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Elias-Fano encoding in Rust.

The Elias-Fano encoding scheme is a quasi-succinct compression method for monotonic integers using gap compression on a Bitset. It allows for decompression of a bit at any position in O(1) time complexity.

Being quasi-succinct, it is therefore almost as good as the best theoretical possible compression as determined by the Shannon-Hartley theorem.

This implementation is based largely on one written in Go by Antonio Mallia, which can be found at his repository amallia/go-ef.


  • Tests
  • Example usage
  • Benchmarks, comparison with other implementations


Add the following line to your Cargo.toml:

+ elias-fano = "1.1.0"

Example Usage

extern crate elias_fano;

use elias_fano::EliasFano;

fn main() {
    let sorted_array = [0, 3, 40, 1000];
    let size = sorted_array.len();

    let mut ef = EliasFano::new(sorted_array[size - 1], size as u64);


    println!("{}", ef.value()); // 1

    match {
        Ok(val) => println!("Retrieved value: {}", val), // 3
        Err(error) => println!("Err: {}", error),        // Out of bounds

    let _ =;
    println!("{}", ef.value()); // 40

    println!("{}", ef.value()); // 0

    let _ = ef.visit(3);
    println!("{}", ef.value()); // 1000


MIT licensed, see LICENSE for more details.

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