Struct KeyIndex 

pub struct KeyIndex { /* private fields */ }

Index from hashed key to bucket of prev-column row indices.

Built once per diff; reused across the next column’s iteration to look up matches without re-hashing prev rows.

Implementations

impl KeyIndex

pub fn build(column: &DataColumn) -> Self

Build the index from column. Time: O(N) hashes.

pub fn lookup( &self, prev: &DataColumn, next: &DataColumn, i: usize, ) -> Option<usize>

Look up which row of prev matches the i-th row of next. Returns the first matching prev index, or None if no match.

Does not consider whether the prev row has already been matched against a different next row — callers wanting “each prev row matches at most one next row” semantics should track consumption themselves (see diff_columns, which does).

pub fn len(&self) -> usize

Number of rows indexed.

pub fn is_empty(&self) -> bool

True when no rows are indexed.