Enum VisibleSet 

pub enum VisibleSet {
    Sparse(HashSet<u32>),
    Dense {
        words: Box<[u64]>,
        len: usize,
    },
}

A set of dense node ids, represented by whichever shape the module-level rule picks at construction.

Variants

Sparse(HashSet<u32>)

Few ids relative to the id space they live in: a hash set.

Dense

Enough ids that a bitset is no larger than the set would be.

words covers [0, words.len() * 64); an id at or past that is absent, which is what makes the probe a bounds check rather than a branch on a separately tracked span. len is the population count, cached because VisibleSet::len is called on paths that cannot afford to popcount a whole bitset.

Fields

words: Box<[u64]>

len: usize

Implementations

impl VisibleSet

pub fn from_ids(ids: impl IntoIterator<Item = u32>) -> VisibleSet

Collect ids and choose a representation by the module’s rule.

Duplicates are collapsed; the rule sees the distinct count.

pub fn contains(&self, id: u32) -> bool

Is id in the set?

The whole point of the type: on VisibleSet::Dense this is a bounds check, a shift and an AND.

pub fn len(&self) -> usize

pub fn is_empty(&self) -> bool

pub fn iter(&self) -> impl Iterator<Item = u32> + '_

The ids in the set, ascending on VisibleSet::Dense and in hash order on VisibleSet::Sparse — no caller depends on the order, and every masked path sorts or keys its own output.

pub fn intersect(&self, other: &VisibleSet) -> VisibleSet

The ids in both sets, with the representation re-chosen for the result.

Two dense sets intersect word-wise with no per-element allocation, which is the operation a multi-leg scope runs on every read. Any other pairing walks the smaller side and probes the larger, so the cost is set by the narrower of the two masks — and narrowing is the only thing an intersection can do.

Trait Implementations

impl Clone for VisibleSet

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for VisibleSet

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

Formats the value using the given formatter.

impl FromIterator<u32> for VisibleSet

fn from_iter<I: IntoIterator<Item = u32>>(ids: I) -> VisibleSet

Creates a value from an iterator.