Trait shortcut::idx::EqualityIndex
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pub trait EqualityIndex<T> { fn lookup<'a>(&'a self, &T) -> Box<Iterator<Item=usize> + 'a>; fn index(&mut self, T, usize); fn undex(&mut self, T, usize); fn estimate(&self) -> usize; }
An EqualityIndex
is an index that can perform efficient equality lookups.
Required Methods
fn lookup<'a>(&'a self, &T) -> Box<Iterator<Item=usize> + 'a>
Return an iterator that yields the indices of all rows that match the given value.
fn index(&mut self, T, usize)
Add the given row index to the index under the given value.
fn undex(&mut self, T, usize)
Remove the given row index under the given value from the index.
fn estimate(&self) -> usize
Give the expected number of rows returned for a key. This method may be called often, and in rapid succession, and so should return quickly.