Struct aho_corasick::automaton::Prefilter

pub struct Prefilter {
    finder: Arc<dyn PrefilterI>,
    memory_usage: usize,
}

A prefilter for accelerating a search.

This crate uses prefilters in the core search implementations to accelerate common cases. They typically only apply to cases where there are a small number of patterns (less than 100 or so), but when they do, thoughput can be boosted considerably, perhaps by an order of magnitude. When a prefilter is active, it is used whenever a search enters an automaton’s start state.

Currently, prefilters cannot be constructed by callers. A Prefilter can only be accessed via the Automaton::prefilter method and used to execute a search. In other words, a prefilter can be used to optimize your own search implementation if necessary, but cannot do much else. If you have a use case for more APIs, please submit an issue.

Fields

finder: Arc<dyn PrefilterI>

memory_usage: usize

Implementations

impl Prefilter

pub fn find_in(&self, haystack: &[u8], span: Span) -> Candidate

Execute a search in the haystack within the span given. If a match or a possible match is returned, then it is guaranteed to occur within the bounds of the span.

If the span provided is invalid for the given haystack, then behavior is unspecified.

pub(crate) fn memory_usage(&self) -> usize

Trait Implementations

impl Clone for Prefilter

fn clone(&self) -> Prefilter

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Prefilter

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

Formats the value using the given formatter.