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perf(parser): use - not saturating_sub #4561

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Merged
graphite-app merged 1 commit into from
Jul 31, 2024
Merged

perf(parser): use - not saturating_sub #4561

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6 changes: 4 additions & 2 deletions crates/oxc_parser/src/lexer/source.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -501,9 +501,11 @@ impl<'a> Source<'a> {
/// Peek next two bytes of source without consuming them.
#[inline]
pub(super) fn peek_2_bytes(&self) -> Option<[u8; 2]> {
if (self.end as usize).saturating_sub(self.ptr as usize) >= 2 {
// `end` is always >= `ptr` so `end - ptr` cannot wrap around.
// No need to use checked/saturating subtraction here.
if (self.end as usize) - (self.ptr as usize) >= 2 {
// SAFETY: The check above ensures that there are at least 2 bytes to
// read from `self.ptr` without overflowing past `self.end`.
// read from `self.ptr` without reading past `self.end`
let bytes = unsafe { self.position().read2() };
Some(bytes)
} else {
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