Struct regex_automata::dfa::onepass::Cache

source ·
pub struct Cache { /* private fields */ }
Expand description

A cache represents mutable state that a one-pass DFA requires during a search.

For a given one-pass DFA, its corresponding cache may be created either via DFA::create_cache, or via Cache::new. They are equivalent in every way, except the former does not require explicitly importing Cache.

A particular Cache is coupled with the one-pass DFA from which it was created. It may only be used with that one-pass DFA. A cache and its allocations may be re-purposed via Cache::reset, in which case, it can only be used with the new one-pass DFA (and not the old one).

Implementations§

source§

impl Cache

source

pub fn new(re: &DFA) -> Cache

Create a new onepass::DFA cache.

A potentially more convenient routine to create a cache is DFA::create_cache, as it does not require also importing the Cache type.

If you want to reuse the returned Cache with some other one-pass DFA, then you must call Cache::reset with the desired one-pass DFA.

source

pub fn reset(&mut self, re: &DFA)

Reset this cache such that it can be used for searching with a different onepass::DFA.

A cache reset permits reusing memory already allocated in this cache with a different one-pass DFA.

§Example

This shows how to re-purpose a cache for use with a different one-pass DFA.

use regex_automata::{dfa::onepass::DFA, Match};

let re1 = DFA::new(r"\w")?;
let re2 = DFA::new(r"\W")?;
let mut caps1 = re1.create_captures();
let mut caps2 = re2.create_captures();

let mut cache = re1.create_cache();
assert_eq!(
    Some(Match::must(0, 0..2)),
    { re1.captures(&mut cache, "Δ", &mut caps1); caps1.get_match() },
);

// 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 one-pass DFA we'd like to use it with.
//
// Similarly, after this reset, using the cache with 're1' is also not
// allowed.
re2.reset_cache(&mut cache);
assert_eq!(
    Some(Match::must(0, 0..3)),
    { re2.captures(&mut cache, "☃", &mut caps2); caps2.get_match() },
);
source

pub fn memory_usage(&self) -> usize

Returns the heap memory usage, in bytes, of this cache.

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

Trait Implementations§

source§

impl Clone for Cache

source§

fn clone(&self) -> Cache

Returns a copy of the value. Read more
1.0.0 · source§

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

Performs copy-assignment from source. Read more
source§

impl Debug for Cache

source§

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

Formats the value using the given formatter. Read more

Auto Trait Implementations§

§

impl Freeze for Cache

§

impl RefUnwindSafe for Cache

§

impl Send for Cache

§

impl Sync for Cache

§

impl Unpin for Cache

§

impl UnwindSafe for Cache

Blanket Implementations§

source§

impl<T> Any for T
where T: 'static + ?Sized,

source§

fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
source§

impl<T> Borrow<T> for T
where T: ?Sized,

source§

fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
source§

impl<T> BorrowMut<T> for T
where T: ?Sized,

source§

fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
source§

impl<T> CloneToUninit for T
where T: Clone,

source§

default unsafe fn clone_to_uninit(&self, dst: *mut T)

🔬This is a nightly-only experimental API. (clone_to_uninit)
Performs copy-assignment from self to dst. Read more
source§

impl<T> From<T> for T

source§

fn from(t: T) -> T

Returns the argument unchanged.

source§

impl<T, U> Into<U> for T
where U: From<T>,

source§

fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

source§

impl<T> ToOwned for T
where T: Clone,

§

type Owned = T

The resulting type after obtaining ownership.
source§

fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
source§

fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
source§

impl<T, U> TryFrom<U> for T
where U: Into<T>,

§

type Error = Infallible

The type returned in the event of a conversion error.
source§

fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
source§

impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

§

type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
source§

fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.