Struct regex_automata::util::search::HalfMatch

pub struct HalfMatch {
    pattern: PatternID,
    offset: usize,
}

A representation of “half” of a match reported by a DFA.

This is called a “half” match because it only includes the end location (or start location for a reverse search) of a match. This corresponds to the information that a single DFA scan can report. Getting the other half of the match requires a second scan with a reversed DFA.

A half match also includes the pattern that matched. The pattern is identified by an ID, which corresponds to its position (starting from 0) relative to other patterns used to construct the corresponding DFA. If only a single pattern is provided to the DFA, then all matches are guaranteed to have a pattern ID of 0.

Fields

pattern: PatternID

The pattern ID.

offset: usize

The offset of the match.

For forward searches, the offset is exclusive. For reverse searches, the offset is inclusive.

Implementations

impl HalfMatch

pub fn new(pattern: PatternID, offset: usize) -> HalfMatch

Create a new half match from a pattern ID and a byte offset.

pub fn must(pattern: usize, offset: usize) -> HalfMatch

Create a new half match from a pattern ID and a byte offset.

This is like HalfMatch::new, but accepts a usize instead of a PatternID. This panics if the given usize is not representable as a PatternID.

pub fn pattern(&self) -> PatternID

Returns the ID of the pattern that matched.

The ID of a pattern is derived from the position in which it was originally inserted into the corresponding DFA. The first pattern has identifier 0, and each subsequent pattern is 1, 2 and so on.

pub fn offset(&self) -> usize

The position of the match.

If this match was produced by a forward search, then the offset is exclusive. If this match was produced by a reverse search, then the offset is inclusive.

Trait Implementations

impl Clone for HalfMatch

fn clone(&self) -> HalfMatch

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for HalfMatch

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

Formats the value using the given formatter.

impl Hash for HalfMatch

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for HalfMatch

fn eq(&self, other: &HalfMatch) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for HalfMatch

impl Eq for HalfMatch

impl StructuralPartialEq for HalfMatch