2 releases
Uses old Rust 2015
0.4.4 | Apr 4, 2017 |
---|---|
0.4.3 | Jul 17, 2016 |
#22 in #bitmask
553 downloads per month
Used in 10 crates
(6 directly)
62KB
1K
SLoC
A compile time sized array of bits.
Documentation is available at https://ambaxter.github.io/bit_array/bit_array
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;
use bit_array::BitArray;
use typenum::{Unsigned, U10000};
// 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);
Dependencies
~365KB