1 files changed, 18 insertions, 0 deletions
diff --git a/third_party/rust/regex/src/find_byte.rs b/third_party/rust/regex/src/find_byte.rs
new file mode 100644
index 0000000000..e95f72afb9
--- /dev/null
+++ b/third_party/rust/regex/src/find_byte.rs
@@ -0,0 +1,18 @@
+/// Searches for the given needle in the given haystack.
+///
+/// If the perf-literal feature is enabled, then this uses the super optimized
+/// memchr crate. Otherwise, it uses the naive byte-at-a-time implementation.
+pub fn find_byte(needle: u8, haystack: &[u8]) -> Option<usize> {
+    #[cfg(not(feature = "perf-literal"))]
+    fn imp(needle: u8, haystack: &[u8]) -> Option<usize> {
+        haystack.iter().position(|&b| b == needle)
+    }
+
+    #[cfg(feature = "perf-literal")]
+    fn imp(needle: u8, haystack: &[u8]) -> Option<usize> {
+        use memchr::memchr;
+        memchr(needle, haystack)
+    }
+
+    imp(needle, haystack)
+}