Struct FilterBuilder

pub struct FilterBuilder {
    pub expected_elements: u64,
    pub false_positive_probability: f64,
    pub size: u64,
    pub hashes: u32,
    pub enable_repeat_insert: bool,
    /* private fields */
}

Builder for Bloom Filters.

Fields

expected_elements: u64

false_positive_probability: f64

size: u64

hashes: u32

enable_repeat_insert: bool

Usage for CountingBloomFilter.

Implementations

impl FilterBuilder

pub fn new(expected_elements: u64, false_positive_probability: f64) -> Self

Constructs a new Bloom Filter Builder by specifying the expected size of the filter and the tolerable false positive probability. The size of the BLoom filter in in bits and the optimal number of hash functions will be inferred from this.

Examples

use fastbloom_rs::FilterBuilder;
let mut builder = FilterBuilder::new(100_000_000, 0.01);
let bloom = builder.build_bloom_filter();

pub fn from_size_and_hashes(size: u64, hashes: u32) -> Self

Constructs a new Bloom Filter Builder by specifying the size of the bloom filter in bits and the number of hashes. The expected size of the filter and the tolerable false positive probability will be inferred from this.

pub fn enable_repeat_insert(&mut self, enable: bool)

Use for CountingBloomFilter.

Example:

use fastbloom_rs::{Deletable, FilterBuilder, Membership};

let mut builder = FilterBuilder::new(100_000, 0.01);
// enable_repeat_insert is true
builder.enable_repeat_insert(true);
let mut cbf = builder.build_counting_bloom_filter();
cbf.add(b"hello"); // modify underlying vector counter.
cbf.add(b"hello"); // modify underlying vector counter.
assert_eq!(cbf.contains(b"hello"), true);
cbf.remove(b"hello");
assert_eq!(cbf.contains(b"hello"), true);
cbf.remove(b"hello");
assert_eq!(cbf.contains(b"hello"), false);

// enable_repeat_insert is false
builder.enable_repeat_insert(false);
let mut cbf = builder.build_counting_bloom_filter();
cbf.add(b"hello"); // modify underlying vector counter.
cbf.add(b"hello"); // not modify underlying vector counter because b"hello" has been added.
assert_eq!(cbf.contains(b"hello"), true);
cbf.remove(b"hello");
assert_eq!(cbf.contains(b"hello"), false);

pub fn build_bloom_filter(&mut self) -> BloomFilter

Constructs a Bloom filter using the specified parameters and computing missing parameters if possible (e.g. the optimal Bloom filter bit size).

pub fn build_counting_bloom_filter(&mut self) -> CountingBloomFilter

Constructs a Counting Bloom filter using the specified parameters and computing missing parameters if possible (e.g. the optimal Bloom filter bit size).

Trait Implementations

impl Clone for FilterBuilder

fn clone(&self) -> FilterBuilder

Returns a duplicate of the value.

const fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for FilterBuilder

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.