Struct cuckoofilter::CuckooFilter

pub struct CuckooFilter<H> { /* fields omitted */ }

A cuckoo filter class exposes a Bloomier filter interface, providing methods of add, delete, contains.

Examples

extern crate cuckoofilter;

let words = vec!["foo", "bar", "xylophone", "milagro"];
let mut cf = cuckoofilter::CuckooFilter::new();

let mut insertions = 0;
for s in &words {
    if cf.test_and_add(s) {
        insertions += 1;
    }
}

assert_eq!(insertions, words.len());
assert_eq!(cf.len(), words.len() as u64);

// Re-add the first element.
cf.add(words[0]);

assert_eq!(cf.len(), words.len() as u64 + 1);

for s in &words {
    cf.delete(s);
}

assert_eq!(cf.len(), 1);
assert!(!cf.is_empty());

cf.delete(words[0]);

assert_eq!(cf.len(), 0);
assert!(cf.is_empty());

Implementations

impl CuckooFilter<DefaultHasher>

pub fn new() -> CuckooFilter<DefaultHasher>

Construct a CuckooFilter with default capacity and hasher.

impl<H> CuckooFilter<H> where
    H: Hasher + Default, 

pub fn with_capacity(cap: u64) -> CuckooFilter<H>

Constructs a Cuckoo Filter with a given max capacity

pub fn contains<T: ?Sized + Hash>(&self, data: &T) -> bool

Checks if data is in the filter.

pub fn add<T: ?Sized + Hash>(&mut self, data: &T) -> bool

Adds data to the filter. Returns true if the insertion was successful. Note that while you can put any hashable type in the same filter, beware for side effects like that the same number can have diferent hashes depending on the type. So for the filter, 4711i64 isn’t the same as 4711u64.

pub fn test_and_add<T: ?Sized + Hash>(&mut self, data: &T) -> bool

Adds data to the filter if it does not exist in the filter yet. Returns true if data was not yet present in the filter and added successfully.

pub fn len(&self) -> u64

Number of items in the filter.

pub fn memory_usage(&self) -> usize

Number of bytes the filter occupies in memory

pub fn is_empty(&self) -> bool

Check if filter is empty

pub fn delete<T: ?Sized + Hash>(&mut self, data: &T) -> bool

Deletes data from the filter. Returns true if data existed in the filter before.

Trait Implementations

impl Default for CuckooFilter<DefaultHasher>

fn default() -> Self

Returns the “default value” for a type.