simplify Iterator::next for PercentEncode

percent_encoding/src/lib.rs

@@ -153,18 +153,15 @@ impl<'a> Iterator for PercentEncode<'a> {
                 self.bytes = remaining;
                 Some(percent_encode_byte(first_byte))
             } else {
-                // The unsafe blocks here are appropriate because the bytes are
-                // confirmed as a subset of UTF-8 in should_percent_encode.
-                for (i, &byte) in remaining.iter().enumerate() {
-                    if self.ascii_set.should_percent_encode(byte) {
-                        // 1 for first_byte + i for previous iterations of this loop
-                        let (unchanged_slice, remaining) = self.bytes.split_at(1 + i);
-                        self.bytes = remaining;
-                        return Some(unsafe { str::from_utf8_unchecked(unchanged_slice) });
-                    }
-                }
-                let unchanged_slice = self.bytes;
-                self.bytes = &[][..];
+                let (unchanged_slice, remaining) = self.bytes.split_at(
+                    // 1 for the first byte + rest in remaining
+                    1 + remaining
+                        .iter()
+                        .position(|&byte| self.ascii_set.should_percent_encode(byte))
+                        .unwrap_or(remaining.len()),
+                );
+                self.bytes = remaining;
+                // SAFETY: bytes are confirmed as a subset of UTF-8 in should_percent_encode.
                 Some(unsafe { str::from_utf8_unchecked(unchanged_slice) })
             }
         } else {