Struct BloomFilter 

pub struct BloomFilter {
    pub bits: Vec<u64>,
    pub num_hashes: u32,
    pub bit_count: u64,
}

A counting-free Bloom filter backed by a Vec<u64> bit array.

Insert items and test membership with a configurable false-positive rate. Deletions are not supported (standard Bloom filter design).

Fields

bits: Vec<u64>

Bit storage (each u64 holds 64 bits).

num_hashes: u32

Number of independent hash functions.

bit_count: u64

Total number of bits (length of the logical bit array).

Implementations

impl BloomFilter

pub fn new(capacity: usize, false_positive_rate: f32) -> Self

Create a new Bloom filter sized for capacity items at a given false_positive_rate.

Uses the standard formulas:

• m = -n * ln(p) / (ln(2))^2 (number of bits)
• k = (m / n) * ln(2) (number of hash functions)

pub fn insert(&mut self, item: &[u8])

Insert item into the filter.

pub fn contains(&self, item: &[u8]) -> bool

Returns true if item may be in the set (possible false positive). Returns false if item is definitely not in the set.

pub fn estimated_count(&self) -> usize

Estimate the number of items inserted using the formula: n̂ = -m / k * ln(1 - X / m) where X is the number of set bits.

pub fn clear(&mut self)

Clear all bits (reset the filter).