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Move next_can_be_plain_scalar as free fn.

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This is, for some reason, a huge pessimization. `rustc` fails to
optimize it as well as it did when it was part of `Scanner`.

This is however kinda needed if I want to avoid having this code
duplicated in every implementation of the input.
This commit is contained in:
Ethiraric 2024-06-14 18:25:40 +02:00
parent 986c45a8b4
commit 65fcb6fde3
1 changed files with 32 additions and 21 deletions
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53
parser/src/scanner.rs
View file

@ -2144,7 +2144,13 @@ impl<T: Input> Scanner<T> {
));
}
if !is_blank_or_breakz(self.input.peek()) && self.next_can_be_plain_scalar() {
if !is_blank_or_breakz(self.input.peek())
&& next_can_be_plain_scalar(
self.input.peek(),
self.input.peek_nth(1),
self.flow_level > 0,
)
{
if self.leading_whitespace {
if leading_break.is_empty() {
string.push_str(&leading_break);
@ -2179,7 +2185,16 @@ impl<T: Input> Scanner<T> {
// hence the `for` loop looping `self.input.bufmaxlen() - 1` times.
self.input.lookahead(self.input.bufmaxlen());
for _ in 0..self.input.bufmaxlen() - 1 {
if is_blank_or_breakz(self.input.peek()) || !self.next_can_be_plain_scalar()
// We need to have `c` and `nc`'s assignations at the beginning of the
// loop. If at the end of it, we will peek one index further than we
// looked ahead. On the first iteration of the loop, `c` is a characte we
// already pushed in `string` a bit earlier.
if is_blank_or_breakz(self.input.peek())
|| !next_can_be_plain_scalar(
self.input.peek(),
self.input.peek_nth(1),
self.flow_level > 0,
)
{
end = true;
break;
@ -2507,25 +2522,6 @@ impl<T: Input> Scanner<T> {
Ok(())
}
/// Check whether the next characters may be part of a plain scalar.
///
/// This function assumes we are not given a blankz character.
// For some reason, `#[inline]` is not enough.
#[allow(clippy::inline_always)]
#[inline(always)]
fn next_can_be_plain_scalar(&self) -> bool {
match self.input.peek() {
// indicators can end a plain scalar, see 7.3.3. Plain Style
':' if is_blank_or_breakz(self.input.peek_nth(1))
|| (self.flow_level > 0 && is_flow(self.input.peek_nth(1))) =>
{
false
}
c if self.flow_level > 0 && is_flow(c) => false,
_ => true,
}
}
/// Return whether the scanner is inside a block but outside of a flow sequence.
fn is_within_block(&self) -> bool {
!self.indents.is_empty()
@ -2595,6 +2591,21 @@ pub enum Chomping {
Keep,
}
/// Check whether the next characters may be part of a plain scalar.
///
/// This function assumes we are not given a blankz character.
// For some reason, `#[inline]` is not enough.
#[allow(clippy::inline_always)]
#[inline(always)]
pub fn next_can_be_plain_scalar(c: char, nc: char, in_flow: bool) -> bool {
match c {
// indicators can end a plain scalar, see 7.3.3. Plain Style
':' if is_blank_or_breakz(nc) || (in_flow && is_flow(nc)) => false,
c if in_flow && is_flow(c) => false,
_ => true,
}
}
#[cfg(test)]
mod test {
#[test]