## bitarray

A compile time sized array of bits

### 3 releases

✓ Uses Rust 2018 edition

 0.1.2 Feb 21, 2019 Feb 21, 2019 Feb 21, 2019

MIT/Apache

64KB
1K SLoC

# bitarray

A compile time sized array of bits.

Documentation is available at https://docs.rs/bitarray/.

### `lib.rs`:

Collections implemented with bit arrays.

# Examples

This is a simple example of the Sieve of Eratosthenes which calculates prime numbers up to a given limit.

``````extern crate typenum;
# extern crate bitarray;
use bitarray::BitArray;
use typenum::{Unsigned, U10000};

# fn main() {

// Store the primes as a BitArray
let primes = {
// Assume all numbers are prime to begin, and then we
// cross off non-primes progressively
let mut bv = BitArray::<u32, U10000>::from_elem(true);

// Neither 0 nor 1 are prime
bv.set(0, false);
bv.set(1, false);

for i in 2.. 1 + (U10000::to_usize() as f64).sqrt() as usize {
// if i is a prime
if bv[i] {
// Mark all multiples of i as non-prime (any multiples below i * i
// will have been marked as non-prime previously)
for j in i.. {
if i * j >= U10000::to_usize() {
break;
}
bv.set(i * j, false)
}
}
}
bv
};

// Simple primality tests below our max bound
let print_primes = 20;
print!("The primes below {} are: ", print_primes);
for x in 0..print_primes {
if primes.get(x).unwrap_or(false) {
print!("{} ", x);
}
}
println!("");

let num_primes = primes.iter().filter(|x| *x).count();
println!("There are {} primes below {}", num_primes, U10000::to_usize());
assert_eq!(num_primes, 1_229);
# }
``````

~250KB