use crate::{
hybrid::{
dfa::{Cache, OverlappingState, DFA},
id::LazyStateID,
},
util::{
prefilter::Prefilter,
search::{HalfMatch, Input, MatchError, Span},
},
};
#[inline(never)]
pub(crate) fn find_fwd(
dfa: &DFA,
cache: &mut Cache,
input: &Input<'_>,
) -> Result<Option<HalfMatch>, MatchError> {
if input.is_done() {
return Ok(None);
}
let pre = if input.get_anchored().is_anchored() {
None
} else {
dfa.get_config().get_prefilter()
};
// So what we do here is specialize four different versions of 'find_fwd':
// one for each of the combinations for 'has prefilter' and 'is earliest
// search'. The reason for doing this is that both of these things require
// branches and special handling in some code that can be very hot,
// and shaving off as much as we can when we don't need it tends to be
// beneficial in ad hoc benchmarks. To see these differences, you often
// need a query with a high match count. In other words, specializing these
// four routines *tends* to help latency more than throughput.
if pre.is_some() {
if input.get_earliest() {
find_fwd_imp(dfa, cache, input, pre, true)
} else {
find_fwd_imp(dfa, cache, input, pre, false)
}
} else {
if input.get_earliest() {
find_fwd_imp(dfa, cache, input, None, true)
} else {
find_fwd_imp(dfa, cache, input, None, false)
}
}
}
#[cfg_attr(feature = "perf-inline", inline(always))]
fn find_fwd_imp(
dfa: &DFA,
cache: &mut Cache,
input: &Input<'_>,
pre: Option<&'_ Prefilter>,
earliest: bool,
) -> Result<Option<HalfMatch>, MatchError> {
// See 'prefilter_restart' docs for explanation.
let universal_start = dfa.get_nfa().look_set_prefix_any().is_empty();
let mut mat = None;
let mut sid = init_fwd(dfa, cache, input)?;
let mut at = input.start();
// This could just be a closure, but then I think it would be unsound
// because it would need to be safe to invoke. This way, the lack of safety
// is clearer in the code below.
macro_rules! next_unchecked {
($sid:expr, $at:expr) => {{
let byte = *input.haystack().get_unchecked($at);
dfa.next_state_untagged_unchecked(cache, $sid, byte)
}};
}
if let Some(ref pre) = pre {
let span = Span::from(at..input.end());
match pre.find(input.haystack(), span) {
None => return Ok(mat),
Some(ref span) => {
at = span.start;
if !universal_start {
sid = prefilter_restart(dfa, cache, &input, at)?;
}
}
}
}
cache.search_start(at);
while at < input.end() {
if sid.is_tagged() {
cache.search_update(at);
sid = dfa
.next_state(cache, sid, input.haystack()[at])
.map_err(|_| gave_up(at))?;
} else {
// SAFETY: There are two safety invariants we need to uphold
// here in the loops below: that 'sid' and 'prev_sid' are valid
// state IDs for this DFA, and that 'at' is a valid index into
// 'haystack'. For the former, we rely on the invariant that
// next_state* and start_state_forward always returns a valid state
// ID (given a valid state ID in the former case), and that we are
// only at this place in the code if 'sid' is untagged. Moreover,
// every call to next_state_untagged_unchecked below is guarded by
// a check that sid is untagged. For the latter safety invariant,
// we always guard unchecked access with a check that 'at' is less
// than 'end', where 'end <= haystack.len()'. In the unrolled loop
// below, we ensure that 'at' is always in bounds.
//
// PERF: For justification of omitting bounds checks, it gives us a
// ~10% bump in search time. This was used for a benchmark:
//
// regex-cli find half hybrid -p '(?m)^.+$' -UBb bigfile
//
// PERF: For justification for the loop unrolling, we use a few
// different tests:
//
// regex-cli find half hybrid -p '\w{50}' -UBb bigfile
// regex-cli find half hybrid -p '(?m)^.+$' -UBb bigfile
// regex-cli find half hybrid -p 'ZQZQZQZQ' -UBb bigfile
//
// And there are three different configurations:
//
// nounroll: this entire 'else' block vanishes and we just
// always use 'dfa.next_state(..)'.
// unroll1: just the outer loop below
// unroll2: just the inner loop below
// unroll3: both the outer and inner loops below
//
// This results in a matrix of timings for each of the above
// regexes with each of the above unrolling configurations:
//
// '\w{50}' '(?m)^.+$' 'ZQZQZQZQ'
// nounroll 1.51s 2.34s 1.51s
// unroll1 1.53s 2.32s 1.56s
// unroll2 2.22s 1.50s 0.61s
// unroll3 1.67s 1.45s 0.61s
//
// Ideally we'd be able to find a configuration that yields the
// best time for all regexes, but alas we settle for unroll3 that
// gives us *almost* the best for '\w{50}' and the best for the
// other two regexes.
//
// So what exactly is going on here? The first unrolling (grouping
// together runs of untagged transitions) specifically targets
// our choice of representation. The second unrolling (grouping
// together runs of self-transitions) specifically targets a common
// DFA topology. Let's dig in a little bit by looking at our
// regexes:
//
// '\w{50}': This regex spends a lot of time outside of the DFA's
// start state matching some part of the '\w' repetition. This
// means that it's a bit of a worst case for loop unrolling that
// targets self-transitions since the self-transitions in '\w{50}'
// are not particularly active for this haystack. However, the
// first unrolling (grouping together untagged transitions)
// does apply quite well here since very few transitions hit
// match/dead/quit/unknown states. It is however worth mentioning
// that if start states are configured to be tagged (which you
// typically want to do if you have a prefilter), then this regex
// actually slows way down because it is constantly ping-ponging
// out of the unrolled loop and into the handling of a tagged start
// state below. But when start states aren't tagged, the unrolled
// loop stays hot. (This is why it's imperative that start state
// tagging be disabled when there isn't a prefilter!)
//
// '(?m)^.+$': There are two important aspects of this regex: 1)
// on this haystack, its match count is very high, much higher
// than the other two regex and 2) it spends the vast majority
// of its time matching '.+'. Since Unicode mode is disabled,
// this corresponds to repeatedly following self transitions for
// the vast majority of the input. This does benefit from the
// untagged unrolling since most of the transitions will be to
// untagged states, but the untagged unrolling does more work than
// what is actually required. Namely, it has to keep track of the
// previous and next state IDs, which I guess requires a bit more
// shuffling. This is supported by the fact that nounroll+unroll1
// are both slower than unroll2+unroll3, where the latter has a
// loop unrolling that specifically targets self-transitions.
//
// 'ZQZQZQZQ': This one is very similar to '(?m)^.+$' because it
// spends the vast majority of its time in self-transitions for
// the (implicit) unanchored prefix. The main difference with
// '(?m)^.+$' is that it has a much lower match count. So there
// isn't much time spent in the overhead of reporting matches. This
// is the primary explainer in the perf difference here. We include
// this regex and the former to make sure we have comparison points
// with high and low match counts.
//
// NOTE: I used 'OpenSubtitles2018.raw.sample.en' for 'bigfile'.
//
// NOTE: In a follow-up, it turns out that the "inner" loop
// mentioned above was a pretty big pessimization in some other
// cases. Namely, it resulted in too much ping-ponging into and out
// of the loop, which resulted in nearly ~2x regressions in search
// time when compared to the originally lazy DFA in the regex crate.
// So I've removed the second loop unrolling that targets the
// self-transition case.
let mut prev_sid = sid;
while at < input.end() {
prev_sid = unsafe { next_unchecked!(sid, at) };
if prev_sid.is_tagged() || at + 3 >= input.end() {
core::mem::swap(&mut prev_sid, &mut sid);
break;
}
at += 1;
sid = unsafe { next_unchecked!(prev_sid, at) };
if sid.is_tagged() {
break;
}
at += 1;
prev_sid = unsafe { next_unchecked!(sid, at) };
if prev_sid.is_tagged() {
core::mem::swap(&mut prev_sid, &mut sid);
break;
}
at += 1;
sid = unsafe { next_unchecked!(prev_sid, at) };
if sid.is_tagged() {
break;
}
at += 1;
}
// If we quit out of the code above with an unknown state ID at
// any point, then we need to re-compute that transition using
// 'next_state', which will do NFA powerset construction for us.
if sid.is_unknown() {
cache.search_update(at);
sid = dfa
.next_state(cache, prev_sid, input.haystack()[at])
.map_err(|_| gave_up(at))?;
}
}
if sid.is_tagged() {
if sid.is_start() {
if let Some(ref pre) = pre {
let span = Span::from(at..input.end());
match pre.find(input.haystack(), span) {
None => {
cache.search_finish(span.end);
return Ok(mat);
}
Some(ref span) => {
// We want to skip any update to 'at' below
// at the end of this iteration and just
// jump immediately back to the next state
// transition at the leading position of the
// candidate match.
//
// ... but only if we actually made progress
// with our prefilter, otherwise if the start
// state has a self-loop, we can get stuck.
if span.start > at {
at = span.start;
if !universal_start {
sid = prefilter_restart(
dfa, cache, &input, at,
)?;
}
continue;
}
}
}
}
} else if sid.is_match() {
let pattern = dfa.match_pattern(cache, sid, 0);
// Since slice ranges are inclusive at the beginning and
// exclusive at the end, and since forward searches report
// the end, we can return 'at' as-is. This only works because
// matches are delayed by 1 byte. So by the time we observe a
// match, 'at' has already been set to 1 byte past the actual
// match location, which is precisely the exclusive ending
// bound of the match.
mat = Some(HalfMatch::new(pattern, at));
if earliest {
cache.search_finish(at);
return Ok(mat);
}
} else if sid.is_dead() {
cache.search_finish(at);
return Ok(mat);
} else if sid.is_quit() {
cache.search_finish(at);
return Err(MatchError::quit(input.haystack()[at], at));
} else {
debug_assert!(sid.is_unknown());
unreachable!("sid being unknown is a bug");
}
}
at += 1;
}
eoi_fwd(dfa, cache, input, &mut sid, &mut mat)?;
cache.search_finish(input.end());
Ok(mat)
}
#[inline(never)]
pub(crate) fn find_rev(
dfa: &DFA,
cache: &mut Cache,
input: &Input<'_>,
) -> Result<Option<HalfMatch>, MatchError> {
if input.is_done() {
return Ok(None);
}
if input.get_earliest() {
find_rev_imp(dfa, cache, input, true)
} else {
find_rev_imp(dfa, cache, input, false)
}
}
#[cfg_attr(feature = "perf-inline", inline(always))]
fn find_rev_imp(
dfa: &DFA,
cache: &mut Cache,
input: &Input<'_>,
earliest: bool,
) -> Result<Option<HalfMatch>, MatchError> {
let mut mat = None;
let mut sid = init_rev(dfa, cache, input)?;
// In reverse search, the loop below can't handle the case of searching an
// empty slice. Ideally we could write something congruent to the forward
// search, i.e., 'while at >= start', but 'start' might be 0. Since we use
// an unsigned offset, 'at >= 0' is trivially always true. We could avoid
// this extra case handling by using a signed offset, but Rust makes it
// annoying to do. So... We just handle the empty case separately.
if input.start() == input.end() {
eoi_rev(dfa, cache, input, &mut sid, &mut mat)?;
return Ok(mat);
}
let mut at = input.end() - 1;
macro_rules! next_unchecked {
($sid:expr, $at:expr) => {{
let byte = *input.haystack().get_unchecked($at);
dfa.next_state_untagged_unchecked(cache, $sid, byte)
}};
}
cache.search_start(at);
loop {
if sid.is_tagged() {
cache.search_update(at);
sid = dfa
.next_state(cache, sid, input.haystack()[at])
.map_err(|_| gave_up(at))?;
} else {
// SAFETY: See comments in 'find_fwd' for a safety argument.
//
// PERF: The comments in 'find_fwd' also provide a justification
// from a performance perspective as to 1) why we elide bounds
// checks and 2) why we do a specialized version of unrolling
// below. The reverse search does have a slightly different
// consideration in that most reverse searches tend to be
// anchored and on shorter haystacks. However, this still makes a
// difference. Take this command for example:
//
// regex-cli find match hybrid -p '(?m)^.+$' -UBb bigfile
//
// (Notice that we use 'find hybrid regex', not 'find hybrid dfa'
// like in the justification for the forward direction. The 'regex'
// sub-command will find start-of-match and thus run the reverse
// direction.)
//
// Without unrolling below, the above command takes around 3.76s.
// But with the unrolling below, we get down to 2.55s. If we keep
// the unrolling but add in bounds checks, then we get 2.86s.
//
// NOTE: I used 'OpenSubtitles2018.raw.sample.en' for 'bigfile'.
let mut prev_sid = sid;
while at >= input.start() {
prev_sid = unsafe { next_unchecked!(sid, at) };
if prev_sid.is_tagged()
|| at <= input.start().saturating_add(3)
{
core::mem::swap(&mut prev_sid, &mut sid);
break;
}
at -= 1;
sid = unsafe { next_unchecked!(prev_sid, at) };
if sid.is_tagged() {
break;
}
at -= 1;
prev_sid = unsafe { next_unchecked!(sid, at) };
if prev_sid.is_tagged() {
core::mem::swap(&mut prev_sid, &mut sid);
break;
}
at -= 1;
sid = unsafe { next_unchecked!(prev_sid, at) };
if sid.is_tagged() {
break;
}
at -= 1;
}
// If we quit out of the code above with an unknown state ID at
// any point, then we need to re-compute that transition using
// 'next_state', which will do NFA powerset construction for us.
if sid.is_unknown() {
cache.search_update(at);
sid = dfa
.next_state(cache, prev_sid, input.haystack()[at])
.map_err(|_| gave_up(at))?;
}
}
if sid.is_tagged() {
if sid.is_start() {
// do nothing
} else if sid.is_match() {
let pattern = dfa.match_pattern(cache, sid, 0);
// Since reverse searches report the beginning of a match
// and the beginning is inclusive (not exclusive like the
// end of a match), we add 1 to make it inclusive.
mat = Some(HalfMatch::new(pattern, at + 1));
if earliest {
cache.search_finish(at);
return Ok(mat);
}
} else if sid.is_dead() {
cache.search_finish(at);
return Ok(mat);
} else if sid.is_quit() {
cache.search_finish(at);
return Err(MatchError::quit(input.haystack()[at], at));
} else {
debug_assert!(sid.is_unknown());
unreachable!("sid being unknown is a bug");
}
}
if at == input.start() {
break;
}
at -= 1;
}
cache.search_finish(input.start());
eoi_rev(dfa, cache, input, &mut sid, &mut mat)?;
Ok(mat)
}
#[inline(never)]
pub(crate) fn find_overlapping_fwd(
dfa: &DFA,
cache: &mut Cache,
input: &Input<'_>,
state: &mut OverlappingState,
) -> Result<(), MatchError> {
state.mat = None;
if input.is_done() {
return Ok(());
}
let pre = if input.get_anchored().is_anchored() {
None
} else {
dfa.get_config().get_prefilter()
};
if pre.is_some() {
find_overlapping_fwd_imp(dfa, cache, input, pre, state)
} else {
find_overlapping_fwd_imp(dfa, cache, input, None, state)
}
}
#[cfg_attr(feature = "perf-inline", inline(always))]
fn find_overlapping_fwd_imp(
dfa: &DFA,
cache: &mut Cache,
input: &Input<'_>,
pre: Option<&'_ Prefilter>,
state: &mut OverlappingState,
) -> Result<(), MatchError> {
// See 'prefilter_restart' docs for explanation.
let universal_start = dfa.get_nfa().look_set_prefix_any().is_empty();
let mut sid = match state.id {
None => {
state.at = input.start();
init_fwd(dfa, cache, input)?
}
Some(sid) => {
if let Some(match_index) = state.next_match_index {
let match_len = dfa.match_len(cache, sid);
if match_index < match_len {
state.next_match_index = Some(match_index + 1);
let pattern = dfa.match_pattern(cache, sid, match_index);
state.mat = Some(HalfMatch::new(pattern, state.at));
return Ok(());
}
}
// Once we've reported all matches at a given position, we need to
// advance the search to the next position.
state.at += 1;
if state.at > input.end() {
return Ok(());
}
sid
}
};
// NOTE: We don't optimize the crap out of this routine primarily because
// it seems like most overlapping searches will have higher match counts,
// and thus, throughput is perhaps not as important. But if you have a use
// case for something faster, feel free to file an issue.
cache.search_start(state.at);
while state.at < input.end() {
sid = dfa
.next_state(cache, sid, input.haystack()[state.at])
.map_err(|_| gave_up(state.at))?;
if sid.is_tagged() {
state.id = Some(sid);
if sid.is_start() {
if let Some(ref pre) = pre {
let span = Span::from(state.at..input.end());
match pre.find(input.haystack(), span) {
None => return Ok(()),
Some(ref span) => {
if span.start > state.at {
state.at = span.start;
if !universal_start {
sid = prefilter_restart(
dfa, cache, &input, state.at,
)?;
}
continue;
}
}
}
}
} else if sid.is_match() {
state.next_match_index = Some(1);
let pattern = dfa.match_pattern(cache, sid, 0);
state.mat = Some(HalfMatch::new(pattern, state.at));
cache.search_finish(state.at);
return Ok(());
} else if sid.is_dead() {
cache.search_finish(state.at);
return Ok(());
} else if sid.is_quit() {
cache.search_finish(state.at);
return Err(MatchError::quit(
input.haystack()[state.at],
state.at,
));
} else {
debug_assert!(sid.is_unknown());
unreachable!("sid being unknown is a bug");
}
}
state.at += 1;
cache.search_update(state.at);
}
let result = eoi_fwd(dfa, cache, input, &mut sid, &mut state.mat);
state.id = Some(sid);
if state.mat.is_some() {
// '1' is always correct here since if we get to this point, this
// always corresponds to the first (index '0') match discovered at
// this position. So the next match to report at this position (if
// it exists) is at index '1'.
state.next_match_index = Some(1);
}
cache.search_finish(input.end());
result
}
#[inline(never)]
pub(crate) fn find_overlapping_rev(
dfa: &DFA,
cache: &mut Cache,
input: &Input<'_>,
state: &mut OverlappingState,
) -> Result<(), MatchError> {
state.mat = None;
if input.is_done() {
return Ok(());
}
let mut sid = match state.id {
None => {
let sid = init_rev(dfa, cache, input)?;
state.id = Some(sid);
if input.start() == input.end() {
state.rev_eoi = true;
} else {
state.at = input.end() - 1;
}
sid
}
Some(sid) => {
if let Some(match_index) = state.next_match_index {
let match_len = dfa.match_len(cache, sid);
if match_index < match_len {
state.next_match_index = Some(match_index + 1);
let pattern = dfa.match_pattern(cache, sid, match_index);
state.mat = Some(HalfMatch::new(pattern, state.at));
return Ok(());
}
}
// Once we've reported all matches at a given position, we need
// to advance the search to the next position. However, if we've
// already followed the EOI transition, then we know we're done
// with the search and there cannot be any more matches to report.
if state.rev_eoi {
return Ok(());
} else if state.at == input.start() {
// At this point, we should follow the EOI transition. This
// will cause us the skip the main loop below and fall through
// to the final 'eoi_rev' transition.
state.rev_eoi = true;
} else {
// We haven't hit the end of the search yet, so move on.
state.at -= 1;
}
sid
}
};
cache.search_start(state.at);
while !state.rev_eoi {
sid = dfa
.next_state(cache, sid, input.haystack()[state.at])
.map_err(|_| gave_up(state.at))?;
if sid.is_tagged() {
state.id = Some(sid);
if sid.is_start() {
// do nothing
} else if sid.is_match() {
state.next_match_index = Some(1);
let pattern = dfa.match_pattern(cache, sid, 0);
state.mat = Some(HalfMatch::new(pattern, state.at + 1));
cache.search_finish(state.at);
return Ok(());
} else if sid.is_dead() {
cache.search_finish(state.at);
return Ok(());
} else if sid.is_quit() {
cache.search_finish(state.at);
return Err(MatchError::quit(
input.haystack()[state.at],
state.at,
));
} else {
debug_assert!(sid.is_unknown());
unreachable!("sid being unknown is a bug");
}
}
if state.at == input.start() {
break;
}
state.at -= 1;
cache.search_update(state.at);
}
let result = eoi_rev(dfa, cache, input, &mut sid, &mut state.mat);
state.rev_eoi = true;
state.id = Some(sid);
if state.mat.is_some() {
// '1' is always correct here since if we get to this point, this
// always corresponds to the first (index '0') match discovered at
// this position. So the next match to report at this position (if
// it exists) is at index '1'.
state.next_match_index = Some(1);
}
cache.search_finish(input.start());
result
}
#[cfg_attr(feature = "perf-inline", inline(always))]
fn init_fwd(
dfa: &DFA,
cache: &mut Cache,
input: &Input<'_>,
) -> Result<LazyStateID, MatchError> {
let sid = dfa.start_state_forward(cache, input)?;
// Start states can never be match states, since all matches are delayed
// by 1 byte.
debug_assert!(!sid.is_match());
Ok(sid)
}
#[cfg_attr(feature = "perf-inline", inline(always))]
fn init_rev(
dfa: &DFA,
cache: &mut Cache,
input: &Input<'_>,
) -> Result<LazyStateID, MatchError> {
let sid = dfa.start_state_reverse(cache, input)?;
// Start states can never be match states, since all matches are delayed
// by 1 byte.
debug_assert!(!sid.is_match());
Ok(sid)
}
#[cfg_attr(feature = "perf-inline", inline(always))]
fn eoi_fwd(
dfa: &DFA,
cache: &mut Cache,
input: &Input<'_>,
sid: &mut LazyStateID,
mat: &mut Option<HalfMatch>,
) -> Result<(), MatchError> {
let sp = input.get_span();
match input.haystack().get(sp.end) {
Some(&b) => {
*sid =
dfa.next_state(cache, *sid, b).map_err(|_| gave_up(sp.end))?;
if sid.is_match() {
let pattern = dfa.match_pattern(cache, *sid, 0);
*mat = Some(HalfMatch::new(pattern, sp.end));
} else if sid.is_quit() {
return Err(MatchError::quit(b, sp.end));
}
}
None => {
*sid = dfa
.next_eoi_state(cache, *sid)
.map_err(|_| gave_up(input.haystack().len()))?;
if sid.is_match() {
let pattern = dfa.match_pattern(cache, *sid, 0);
*mat = Some(HalfMatch::new(pattern, input.haystack().len()));
}
// N.B. We don't have to check 'is_quit' here because the EOI
// transition can never lead to a quit state.
debug_assert!(!sid.is_quit());
}
}
Ok(())
}
#[cfg_attr(feature = "perf-inline", inline(always))]
fn eoi_rev(
dfa: &DFA,
cache: &mut Cache,
input: &Input<'_>,
sid: &mut LazyStateID,
mat: &mut Option<HalfMatch>,
) -> Result<(), MatchError> {
let sp = input.get_span();
if sp.start > 0 {
let byte = input.haystack()[sp.start - 1];
*sid = dfa
.next_state(cache, *sid, byte)
.map_err(|_| gave_up(sp.start))?;
if sid.is_match() {
let pattern = dfa.match_pattern(cache, *sid, 0);
*mat = Some(HalfMatch::new(pattern, sp.start));
} else if sid.is_quit() {
return Err(MatchError::quit(byte, sp.start - 1));
}
} else {
*sid =
dfa.next_eoi_state(cache, *sid).map_err(|_| gave_up(sp.start))?;
if sid.is_match() {
let pattern = dfa.match_pattern(cache, *sid, 0);
*mat = Some(HalfMatch::new(pattern, 0));
}
// N.B. We don't have to check 'is_quit' here because the EOI
// transition can never lead to a quit state.
debug_assert!(!sid.is_quit());
}
Ok(())
}
/// Re-compute the starting state that a DFA should be in after finding a
/// prefilter candidate match at the position `at`.
///
/// It is always correct to call this, but not always necessary. Namely,
/// whenever the DFA has a universal start state, the DFA can remain in the
/// start state that it was in when it ran the prefilter. Why? Because in that
/// case, there is only one start state.
///
/// When does a DFA have a universal start state? In precisely cases where
/// it has no look-around assertions in its prefix. So for example, `\bfoo`
/// does not have a universal start state because the start state depends on
/// whether the byte immediately before the start position is a word byte or
/// not. However, `foo\b` does have a universal start state because the word
/// boundary does not appear in the pattern's prefix.
///
/// So... most cases don't need this, but when a pattern doesn't have a
/// universal start state, then after a prefilter candidate has been found, the
/// current state *must* be re-litigated as if computing the start state at the
/// beginning of the search because it might change. That is, not all start
/// states are created equal.
///
/// Why avoid it? Because while it's not super expensive, it isn't a trivial
/// operation to compute the start state. It is much better to avoid it and
/// just state in the current state if you know it to be correct.
#[cfg_attr(feature = "perf-inline", inline(always))]
fn prefilter_restart(
dfa: &DFA,
cache: &mut Cache,
input: &Input<'_>,
at: usize,
) -> Result<LazyStateID, MatchError> {
let mut input = input.clone();
input.set_start(at);
init_fwd(dfa, cache, &input)
}
/// A convenience routine for constructing a "gave up" match error.
#[cfg_attr(feature = "perf-inline", inline(always))]
fn gave_up(offset: usize) -> MatchError {
MatchError::gave_up(offset)
}
Codebase Browser
chromium