Struct aho_corasick::nfa::noncontiguous::NFA
source · [−]pub struct NFA { /* private fields */ }
Expand description
A noncontiguous NFA implementation of Aho-Corasick.
When possible, prefer using AhoCorasick
instead of
this type directly. Using an NFA
directly is typically only necessary
when one needs access to the Automaton
trait implementation.
This NFA represents the “core” implementation of Aho-Corasick in this crate. Namely, constructing this NFA involving building a trie and then filling in the failure transitions between states, similar to what is described in any standard textbook description of Aho-Corasick.
In order to minimize heap usage and to avoid additional construction costs, this implementation represents the transitions of all states as distinct sparse memory allocations. This is where it gets its name from. That is, this NFA has no contiguous memory allocation for its transition table. Each state gets its own allocation.
While the sparse representation keeps memory usage to somewhat reasonable
levels, it is still quite large and also results in somewhat mediocre
search performance. For this reason, it is almost always a good idea to
use a contiguous::NFA
instead. It is
marginally slower to build, but has higher throughput and can sometimes use
an order of magnitude less memory. The main reason to use a noncontiguous
NFA is when you need the fastest possible construction time, or when a
contiguous NFA does not have the desired capacity. (The total number of NFA
states it can have is fewer than a noncontiguous NFA.)
Example
This example shows how to build an NFA
directly and use it to execute
Automaton::try_find
:
use aho_corasick::{
automaton::Automaton,
nfa::noncontiguous::NFA,
Input, Match,
};
let patterns = &["b", "abc", "abcd"];
let haystack = "abcd";
let nfa = NFA::new(patterns).unwrap();
assert_eq!(
Some(Match::must(0, 1..2)),
nfa.try_find(&Input::new(haystack))?,
);
It is also possible to implement your own version of try_find
. See the
Automaton
documentation for an example.
Implementations
Trait Implementations
sourceimpl Automaton for NFA
impl Automaton for NFA
sourcefn start_state(&self, anchored: Anchored) -> Result<StateID, MatchError>
fn start_state(&self, anchored: Anchored) -> Result<StateID, MatchError>
sourcefn is_special(&self, sid: StateID) -> bool
fn is_special(&self, sid: StateID) -> bool
sourcefn is_dead(&self, sid: StateID) -> bool
fn is_dead(&self, sid: StateID) -> bool
sourcefn is_match(&self, sid: StateID) -> bool
fn is_match(&self, sid: StateID) -> bool
sourcefn is_start(&self, sid: StateID) -> bool
fn is_start(&self, sid: StateID) -> bool
sourcefn match_kind(&self) -> MatchKind
fn match_kind(&self) -> MatchKind
sourcefn patterns_len(&self) -> usize
fn patterns_len(&self) -> usize
sourcefn pattern_len(&self, pid: PatternID) -> usize
fn pattern_len(&self, pid: PatternID) -> usize
sourcefn min_pattern_len(&self) -> usize
fn min_pattern_len(&self) -> usize
sourcefn max_pattern_len(&self) -> usize
fn max_pattern_len(&self) -> usize
sourcefn match_len(&self, sid: StateID) -> usize
fn match_len(&self, sid: StateID) -> usize
sourcefn match_pattern(&self, sid: StateID, index: usize) -> PatternID
fn match_pattern(&self, sid: StateID, index: usize) -> PatternID
sourcefn memory_usage(&self) -> usize
fn memory_usage(&self) -> usize
sourcefn prefilter(&self) -> Option<&Prefilter>
fn prefilter(&self) -> Option<&Prefilter>
sourcefn try_find(&self, input: &Input<'_>) -> Result<Option<Match>, MatchError>
fn try_find(&self, input: &Input<'_>) -> Result<Option<Match>, MatchError>
sourcefn try_find_overlapping(
&self,
input: &Input<'_>,
state: &mut OverlappingState
) -> Result<(), MatchError>
fn try_find_overlapping(
&self,
input: &Input<'_>,
state: &mut OverlappingState
) -> Result<(), MatchError>
sourcefn try_find_iter<'a, 'h>(
&'a self,
input: Input<'h>
) -> Result<FindIter<'a, 'h, Self>, MatchError>where
Self: Sized,
fn try_find_iter<'a, 'h>(
&'a self,
input: Input<'h>
) -> Result<FindIter<'a, 'h, Self>, MatchError>where
Self: Sized,
sourcefn try_find_overlapping_iter<'a, 'h>(
&'a self,
input: Input<'h>
) -> Result<FindOverlappingIter<'a, 'h, Self>, MatchError>where
Self: Sized,
fn try_find_overlapping_iter<'a, 'h>(
&'a self,
input: Input<'h>
) -> Result<FindOverlappingIter<'a, 'h, Self>, MatchError>where
Self: Sized,
sourcefn try_replace_all<B>(
&self,
haystack: &str,
replace_with: &[B]
) -> Result<String, MatchError>where
Self: Sized,
B: AsRef<str>,
fn try_replace_all<B>(
&self,
haystack: &str,
replace_with: &[B]
) -> Result<String, MatchError>where
Self: Sized,
B: AsRef<str>,
haystack
with
strings from replace_with
depending on the pattern that
matched. The replace_with
slice must have length equal to
Automaton::patterns_len
. Read moresourcefn try_replace_all_bytes<B>(
&self,
haystack: &[u8],
replace_with: &[B]
) -> Result<Vec<u8>, MatchError>where
Self: Sized,
B: AsRef<[u8]>,
fn try_replace_all_bytes<B>(
&self,
haystack: &[u8],
replace_with: &[B]
) -> Result<Vec<u8>, MatchError>where
Self: Sized,
B: AsRef<[u8]>,
haystack
with
strings from replace_with
depending on the pattern that
matched. The replace_with
slice must have length equal to
Automaton::patterns_len
. Read moresourcefn try_replace_all_with<F>(
&self,
haystack: &str,
dst: &mut String,
replace_with: F
) -> Result<(), MatchError>where
Self: Sized,
F: FnMut(&Match, &str, &mut String) -> bool,
fn try_replace_all_with<F>(
&self,
haystack: &str,
dst: &mut String,
replace_with: F
) -> Result<(), MatchError>where
Self: Sized,
F: FnMut(&Match, &str, &mut String) -> bool,
haystack
by calling the
replace_with
closure given. Read moresourcefn try_replace_all_with_bytes<F>(
&self,
haystack: &[u8],
dst: &mut Vec<u8>,
replace_with: F
) -> Result<(), MatchError>where
Self: Sized,
F: FnMut(&Match, &[u8], &mut Vec<u8>) -> bool,
fn try_replace_all_with_bytes<F>(
&self,
haystack: &[u8],
dst: &mut Vec<u8>,
replace_with: F
) -> Result<(), MatchError>where
Self: Sized,
F: FnMut(&Match, &[u8], &mut Vec<u8>) -> bool,
haystack
by calling the
replace_with
closure given. Read moresourcefn try_stream_find_iter<'a, R: Read>(
&'a self,
rdr: R
) -> Result<StreamFindIter<'a, Self, R>, MatchError>where
Self: Sized,
fn try_stream_find_iter<'a, R: Read>(
&'a self,
rdr: R
) -> Result<StreamFindIter<'a, Self, R>, MatchError>where
Self: Sized,
sourcefn try_stream_replace_all<R, W, B>(
&self,
rdr: R,
wtr: W,
replace_with: &[B]
) -> Result<()>where
Self: Sized,
R: Read,
W: Write,
B: AsRef<[u8]>,
fn try_stream_replace_all<R, W, B>(
&self,
rdr: R,
wtr: W,
replace_with: &[B]
) -> Result<()>where
Self: Sized,
R: Read,
W: Write,
B: AsRef<[u8]>,
rdr
with strings from
replace_with
depending on the pattern that matched, and writes the
result to wtr
. The replace_with
slice must have length equal to
Automaton::patterns_len
. Read moresourcefn try_stream_replace_all_with<R, W, F>(
&self,
rdr: R,
wtr: W,
replace_with: F
) -> Result<()>where
Self: Sized,
R: Read,
W: Write,
F: FnMut(&Match, &[u8], &mut W) -> Result<()>,
fn try_stream_replace_all_with<R, W, F>(
&self,
rdr: R,
wtr: W,
replace_with: F
) -> Result<()>where
Self: Sized,
R: Read,
W: Write,
F: FnMut(&Match, &[u8], &mut W) -> Result<()>,
rdr
by calling the
replace_with
closure given and writing the result to wtr
. Read more