#![allow(dead_code)]
use crate::{accel::FwdPrefixSearch, engine, Error, Match, Regex, RegexBuilder};
fn fwd_prefix_impl<const IS_MATCH: bool>(
fwd: &mut engine::LDFA,
b: &mut RegexBuilder,
fixed_length: Option<u32>,
has_anchors: bool,
fwd_prefix: &FwdPrefixSearch,
input: &[u8],
matches: &mut Vec<Match>,
) -> Result<bool, Error> {
let prefix_len = fwd_prefix.len();
if fixed_length == Some(prefix_len as u32) && !has_anchors {
if IS_MATCH {
if fwd_prefix.is_literal() {
return Ok(fwd_prefix.find_fwd(input, 0).is_some());
}
} else if fwd_prefix.find_all_literal(input, matches) {
return Ok(false);
}
}
let mut search_start = 0;
{
let mt = fwd.mt_lookup[input[0] as usize];
let state = fwd.begin_table[mt as usize] as u32;
if state != fwd.pruned as u32 {
let max_end = fwd.scan_fwd_from(b, state, 1, input)?;
if max_end != engine::NO_MATCH && max_end > 0 {
if IS_MATCH {
return Ok(true);
}
matches.push(Match {
start: 0,
end: max_end,
});
search_start = max_end;
}
}
}
while let Some(candidate) = fwd_prefix.find_fwd(input, search_start) {
let state = fwd.walk_input(b, candidate, prefix_len, input)?;
if state != 0 {
let max_end =
fwd.scan_fwd_from(b, state, candidate + prefix_len, input)?;
if max_end != engine::NO_MATCH && max_end > candidate {
if IS_MATCH {
return Ok(true);
}
matches.push(Match {
start: candidate,
end: max_end,
});
search_start = max_end;
continue;
}
}
search_start = candidate + 1;
}
Ok(false)
}
fn try_emit_zero_width<const IS_MATCH: bool>(
fwd: &mut engine::LDFA,
b: &mut RegexBuilder,
lb_len: usize,
fwd_prefix: &FwdPrefixSearch,
input: &[u8],
at: usize,
matches: &mut Vec<Match>,
) -> Result<bool, Error> {
if at < lb_len {
return Ok(false);
}
let lb_pos = at - lb_len;
if fwd_prefix.find_fwd(input, lb_pos) != Some(lb_pos) {
return Ok(false);
}
let zw = fwd.scan_fwd_from(b, engine::DFA_INITIAL as u32, at, input)?;
if zw == at {
if IS_MATCH {
return Ok(true);
}
matches.push(Match { start: at, end: at });
}
Ok(false)
}
fn fwd_lb_prefix_impl<const IS_MATCH: bool>(
fwd: &mut engine::LDFA,
b: &mut RegexBuilder,
lb_len: usize,
fwd_lb_begin_nullable: bool,
body_nullable: bool,
fwd_prefix: &FwdPrefixSearch,
input: &[u8],
matches: &mut Vec<Match>,
) -> Result<bool, Error> {
let mut search_start = 0;
if fwd_lb_begin_nullable {
let max_end = fwd.scan_fwd_slow(b, 0, input)?;
if max_end != engine::NO_MATCH {
if IS_MATCH {
return Ok(true);
}
matches.push(Match {
start: 0,
end: max_end,
});
if max_end > 0 && body_nullable {
if try_emit_zero_width::<IS_MATCH>(fwd, b, lb_len, fwd_prefix, input, max_end, matches)? {
return Ok(true);
}
}
search_start = if max_end == 0 { 1 } else { max_end };
}
}
while let Some(candidate) = fwd_prefix.find_fwd(input, search_start) {
let body_start = candidate + lb_len;
let max_end = fwd.scan_fwd_from(
b,
engine::DFA_INITIAL as u32,
body_start,
input,
)?;
if max_end != engine::NO_MATCH {
if IS_MATCH {
return Ok(true);
}
matches.push(Match {
start: body_start,
end: max_end,
});
if max_end > body_start && body_nullable {
if try_emit_zero_width::<IS_MATCH>(fwd, b, lb_len, fwd_prefix, input, max_end, matches)? {
return Ok(true);
}
}
search_start = max_end;
} else {
search_start = body_start;
}
}
Ok(false)
}
impl Regex {
pub(crate) fn find_all_fwd_prefix(
&self,
fwd_prefix: &FwdPrefixSearch,
input: &[u8],
) -> Result<Vec<Match>, Error> {
let inner = &mut *self.inner.lock().unwrap();
inner.matches.clear();
fwd_prefix_impl::<false>(
&mut inner.fwd,
&mut inner.b,
self.fixed_length,
self.has_anchors,
fwd_prefix,
input,
&mut inner.matches,
)?;
Ok(inner.matches.clone())
}
pub(crate) fn is_match_fwd_prefix(
&self,
fwd_prefix: &FwdPrefixSearch,
input: &[u8],
) -> Result<bool, Error> {
let inner = &mut *self.inner.lock().unwrap();
inner.matches.clear();
fwd_prefix_impl::<true>(
&mut inner.fwd,
&mut inner.b,
self.fixed_length,
self.has_anchors,
fwd_prefix,
input,
&mut inner.matches,
)
}
pub(crate) fn is_match_fwd_lb_prefix(
&self,
fwd_prefix: &FwdPrefixSearch,
input: &[u8],
) -> Result<bool, Error> {
let inner = &mut *self.inner.lock().unwrap();
inner.matches.clear();
fwd_lb_prefix_impl::<true>(
&mut inner.fwd,
&mut inner.b,
self.lb_check_bytes as usize,
self.fwd_lb_begin_nullable,
self.fwd_lb_body_nullable,
fwd_prefix,
input,
&mut inner.matches,
)
}
pub(crate) fn find_all_fwd_lb_prefix(
&self,
fwd_prefix: &FwdPrefixSearch,
input: &[u8],
) -> Result<Vec<Match>, Error> {
let inner = &mut *self.inner.lock().unwrap();
inner.matches.clear();
fwd_lb_prefix_impl::<false>(
&mut inner.fwd,
&mut inner.b,
self.lb_check_bytes as usize,
self.fwd_lb_begin_nullable,
self.fwd_lb_body_nullable,
fwd_prefix,
input,
&mut inner.matches,
)?;
Ok(inner.matches.clone())
}
}