faster charsearcher

Author: bend-n

library/core/src/str/pattern.rs

@@ -432,13 +432,14 @@ unsafe impl<'a> Searcher<'a> for CharSearcher<'a> {
     #[inline(always)]
     fn next_match(&mut self) -> Option<(usize, usize)> {
         if self.utf8_size == 1 {
-            return match self
-                .haystack
-                .as_bytes()
-                .get(self.finger..self.finger_back)?
-                .iter()
-                .position(|x| *x == self.utf8_encoded[0])
-            {
+            let find = |haystack: &[u8]| {
+                if haystack.len() < 64 {
+                    haystack.iter().position(|&x| x == self.utf8_encoded[0])
+                } else {
+                    memchr::memchr(self.utf8_encoded[0], haystack)
+                }
+            };
+            return match find(self.haystack.as_bytes().get(self.finger..self.finger_back)?) {
                 Some(x) => {
                     self.finger += x + 1;
                     Some((self.finger - 1, self.finger))
@@ -514,13 +515,14 @@ unsafe impl<'a> ReverseSearcher<'a> for CharSearcher<'a> {
     #[inline]
     fn next_match_back(&mut self) -> Option<(usize, usize)> {
         if self.utf8_size == 1 {
-            return match self
-                .haystack
-                .get(self.finger..self.finger_back)?
-                .as_bytes()
-                .iter()
-                .rposition(|&x| x == self.utf8_encoded[0])
-            {
+            let find = |haystack: &[u8]| {
+                if haystack.len() < 64 {
+                    memchr::memrchr(self.utf8_encoded[0], haystack)
+                } else {
+                    haystack.iter().rposition(|&x| x == self.utf8_encoded[0])
+                }
+            };
+            return match find(self.haystack.as_bytes().get(self.finger..self.finger_back)?) {
                 Some(x) => {
                     self.finger_back = self.finger + x;
                     Some((self.finger_back, self.finger_back + 1))