Struct xx_bloomfilter::Bloom

pub struct Bloom { /* fields omitted */ }

Bloom filter structure

Methods

impl Bloom

pub fn new(bitmap_size: usize, items_count: usize) -> Self

Create a new bloom filter structure. bitmap_size is the size in bytes (not bits) that will be allocated in memory items_count is an estimation of the maximum number of items to store.

pub fn new_with_rate(items_count: usize, fp_p: f64) -> Self

Create a new bloom filter structure. items_count is an estimation of the maximum number of items to store. fp_p is the wanted rate of false positives, in ]0.0, 1.0[

extern crate xx_bloomfilter;
extern crate rand;

use xx_bloomfilter::Bloom;

let mut bloom = Bloom::new_with_rate(1_000_000, 1e-6);
let item: u64 = rand::random();
assert_eq!(false, bloom.check_and_add(&item));
assert_eq!(true, bloom.check(&item));
// Clear all values
bloom.clear();
assert_eq!(false, bloom.check_and_add(&item));

pub fn from_existing_struct(other: &Bloom) -> Self

pub fn from_existing(
    bitmap: &[u8],
    bitmap_size: u64,
    k: u64,
    xx: (XxHash64, XxHash64)
) -> Self

Create a bloom filter structure with an existing state. The state is assumed to be retrieved from an existing bloom filter.

pub fn compute_bitmap_size(items_count: usize, fp_p: f64) -> usize

Compute a recommended bitmap size for items_count items and a fp_p rate of false positives. fp_p has to be within the ]0.0, 1.0[ range.

pub fn add<T: Hash>(&mut self, item: &T)

Record the presence of an item.

pub fn check<T: Hash>(&self, item: &T) -> bool

Check if an item is present in the set. There can be false positives, but no false negatives.

pub fn check_and_add<T: Hash>(&mut self, item: &T) -> bool

Record the presence of an item in the set, and return the previous state of this item.

pub fn bitmap(&self) -> BitVec

Return the bitmap

pub fn number_of_bits(&self) -> u64

Return the number of bits in the filter

pub fn number_of_hash_functions(&self) -> u64

Return the number of hash functions used for check and set

pub fn xx(&self) -> (XxHash64, XxHash64)

pub fn clear(&mut self)

Clear all of the bits in the filter, removing all keys from the set