Struct SingletonHashTrieIter 

pub struct SingletonHashTrieIter { /* private fields */ }

A singleton “hash trie” containing one value.

Implements HashTrieIterator over a single-value relation. Used by the const-view rewrite to expose a Const_c<id> = {c<id>} predicate as if it were a real hash-trie-backed relation.

Implementations

impl SingletonHashTrieIter

pub fn new(value: usize, hash: u64) -> Self

Construct a new singleton positioned at its root (pre-open).

hash is the precomputed u64 hash of value under whichever kermit_iters::HashStrategy the caller uses for the matching HashTrie<H>. Keeping the strategy out of this struct lets the singleton remain Sized without a phantom parameter and lets a generic caller (e.g. hash_join<R, H>) drive both the trie and the singleton with the same hash function.

Trait Implementations

impl Clone for SingletonHashTrieIter

fn clone(&self) -> SingletonHashTrieIter

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for SingletonHashTrieIter

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

Formats the value using the given formatter.

impl HashTrieIterable for SingletonHashTrieIter

fn hash_trie_iter(&self) -> impl HashTrieIterator

Returns a HashTrieIterator over this structure.

impl HashTrieIterator for SingletonHashTrieIter

fn key(&self) -> Option<u64>

Hash at the current bucket, or None if at end or not yet opened.

fn next(&mut self) -> Option<u64>

Advance to the next occupied bucket. Returns its hash, or None if no further bucket exists at this level.

fn lookup(&mut self, hash: u64) -> bool

Position at the bucket with exact hash hash. Returns true iff a matching bucket exists.

fn size(&self) -> usize

Number of occupied buckets in the current node — the paper’s size(I_j). Used by the algorithm to pick the smallest table at each level (argmin size).

fn at_end(&self) -> bool

true iff the iterator is positioned past the last occupied bucket in the current node.

fn open(&mut self) -> bool

Descend into the child node at the current bucket. Returns false if already at the leaf level or if the current bucket is empty.

fn up(&mut self) -> bool

Ascend to the parent node. Returns false at the root.

fn leaf_tuples(&self) -> Option<&[Vec<usize>]>

Tuple chain at the current leaf bucket. Returns Some(&[…]) iff the current node is a leaf and the current bucket is occupied; otherwise None.

impl JoinIterable for SingletonHashTrieIter