Struct MapWithDictBitpacked 

pub struct MapWithDictBitpacked<K, const B: usize = 32, const S: usize = 8, ST = u8, H = WyHash>
where
    ST: PrimInt + Unsigned,
    H: Hasher + Default,
{ /* private fields */ }

An efficient, immutable hash map with bit-packed Vec<u32> values for optimized space usage.

Serde and untrusted input

Deserialization performs best-effort consistency checks (key/MPHF alignment, value index bounds, num_bits <= 32), but does not verify that every dictionary entry covers its packed blocks. A crafted payload can therefore pass deserialization and later panic in get_values/values/iter. Only deserialize payloads you trust; do not treat this type as a security boundary.

Implementations

impl<K, const B: usize, const S: usize, ST, H> MapWithDictBitpacked<K, B, S, ST, H>

where K: Hash + PartialEq + Clone, ST: PrimInt + Unsigned, H: Hasher + Default,

pub fn from_iter_with_params<I>(iter: I, gamma: f32) -> Result<Self, Error>

where I: IntoIterator<Item = (K, Vec<u32>)>,

Constructs a MapWithDictBitpacked from an iterator of key-value pairs and MPHF function params.

pub fn get_values<Q>(&self, key: &Q, values: &mut [u32]) -> bool

where K: Borrow<Q> + PartialEq<Q>, Q: Hash + Eq + ?Sized,

Updates values to the array of values corresponding to the key. Returns false if the key is not not present in the map.

Examples

let map = MapWithDictBitpacked::try_from(HashMap::from([(1, vec![2]), (3, vec![4])])).unwrap();
let mut values = [0];
assert_eq!(map.get_values(&1, &mut values), true);
assert_eq!(values, [2]);
assert_eq!(map.get_values(&2, &mut values), false);

Panics

Panics if self was deserialized from a crafted payload whose dictionary entry is truncated (see the type-level note about untrusted input).

pub fn len(&self) -> usize

Returns the number of keys in the map.

Examples

let map = MapWithDictBitpacked::try_from(HashMap::from([(1, vec![2]), (3, vec![4])])).unwrap();
assert_eq!(map.len(), 2);

pub fn is_empty(&self) -> bool

Returns true if the map contains no elements.

Examples

let map = MapWithDictBitpacked::try_from(HashMap::from([(0, vec![0]); 0])).unwrap();
assert_eq!(map.is_empty(), true);
let map = MapWithDictBitpacked::try_from(HashMap::from([(1, vec![2]), (3, vec![4])])).unwrap();
assert_eq!(map.is_empty(), false);

pub fn contains_key<Q>(&self, key: &Q) -> bool

where K: Borrow<Q> + PartialEq<Q>, Q: Hash + Eq + ?Sized,

Checks if the map contains the specified key.

Examples

let map = MapWithDictBitpacked::try_from(HashMap::from([(1, vec![2]), (3, vec![4])])).unwrap();
assert_eq!(map.contains_key(&1), true);
assert_eq!(map.contains_key(&2), false);

pub fn iter(&self, n: usize) -> impl Iterator<Item = (&K, Vec<u32>)>

Returns an iterator over the map, yielding key-value pairs.

Examples

let map = MapWithDictBitpacked::try_from(HashMap::from([(1, vec![2]), (3, vec![4])])).unwrap();
for (key, val) in map.iter(1) {
    println!("key: {key} val: {val:?}");
}

pub fn keys(&self) -> impl Iterator<Item = &K>

Returns an iterator over the keys of the map.

Examples

let map = MapWithDictBitpacked::try_from(HashMap::from([(1, vec![2]), (3, vec![4])])).unwrap();
for key in map.keys() {
    println!("{key}");
}

pub fn values(&self, n: usize) -> impl Iterator<Item = Vec<u32>> + '_

Returns an iterator over the values of the map.

Examples

let map = MapWithDictBitpacked::try_from(HashMap::from([(1, vec![2]), (3, vec![4])])).unwrap();
for val in map.values(1) {
    println!("{val:?}");
}

pub fn size(&self) -> usize

Returns the total number of bytes occupied by the structure.

Examples

let map = MapWithDictBitpacked::try_from(HashMap::from([(1, vec![2]), (3, vec![4])])).unwrap();
assert_eq!(map.size(), 394);

Trait Implementations

impl<K: Default, const B: usize, const S: usize, ST, H> Default for MapWithDictBitpacked<K, B, S, ST, H>

where ST: PrimInt + Unsigned + Default, H: Hasher + Default + Default,

fn default() -> MapWithDictBitpacked<K, B, S, ST, H>

Returns the “default value” for a type.

impl<K> TryFrom<HashMap<K, Vec<u32>>> for MapWithDictBitpacked<K>

where K: PartialEq + Hash + Clone,

Creates a MapWithDictBitpacked from a HashMap.

type Error = Error

The type returned in the event of a conversion error.

fn try_from(value: HashMap<K, Vec<u32>>) -> Result<Self, Self::Error>

Performs the conversion.