impl Cache

fn new(re: &Regex) -> Cache

Create a new cache for the given Regex.

The cache returned should only be used for searches for the given Regex. If you want to reuse the cache for another Regex, then you must call Cache::reset with that Regex.

fn reset(&mut self, re: &Regex)

Reset this cache such that it can be used for searching with the given Regex (and only that Regex).

A cache reset permits reusing memory already allocated in this cache with a different Regex.

Resetting a cache sets its "clear count" to 0. This is relevant if the Regex has been configured to "give up" after it has cleared the cache a certain number of times.

Example

This shows how to re-purpose a cache for use with a different Regex.

# if cfg!(miri) { return Ok(()); } // miri takes too long
use regex_automata::{hybrid::regex::Regex, Match};

let re1 = Regex::new(r"\w")?;
let re2 = Regex::new(r"\W")?;

let mut cache = re1.create_cache();
assert_eq!(
    Some(Match::must(0, 0..2)),
    re1.find(&mut cache, "Δ"),
);

// Using 'cache' with re2 is not allowed. It may result in panics or
// incorrect results. In order to re-purpose the cache, we must reset
// it with the Regex we'd like to use it with.
//
// Similarly, after this reset, using the cache with 're1' is also not
// allowed.
cache.reset(&re2);
assert_eq!(
    Some(Match::must(0, 0..3)),
    re2.find(&mut cache, "☃"),
);

# Ok::<(), Box<dyn std::error::Error>>(())

fn forward(&mut self) -> &Cache

Return a reference to the forward cache.

fn reverse(&mut self) -> &Cache

Return a reference to the reverse cache.

fn forward_mut(&mut self) -> &mut Cache

Return a mutable reference to the forward cache.

If you need mutable references to both the forward and reverse caches, then use Cache::as_parts_mut.

fn reverse_mut(&mut self) -> &mut Cache

Return a mutable reference to the reverse cache.

If you need mutable references to both the forward and reverse caches, then use Cache::as_parts_mut.

fn as_parts(&self) -> (&Cache, &Cache)

Return references to the forward and reverse caches, respectively.

fn as_parts_mut(&mut self) -> (&mut Cache, &mut Cache)

Return mutable references to the forward and reverse caches, respectively.

fn memory_usage(&self) -> usize

Returns the heap memory usage, in bytes, as a sum of the forward and reverse lazy DFA caches.

This does not include the stack size used up by this cache. To compute that, use std::mem::size_of::<Cache>().