Optimize for ASCII case in floor/ceil_grapheme.

1 files changed, 4 insertions, 1 deletions

diff --git a/src/main.rs b/src/main.rs
index 0dfe335..c5ea852 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -75,7 +75,7 @@ fn floor_grapheme_cluster(
     line: &Rope,
     offset: usize,
 ) -> Result<usize, Box<dyn Error>> {
-    if offset == 0 || offset == line.len() {
+    if offset == 0 || offset == line.len() || line.byte(offset) < 128 {
         return Ok(offset);
     }
     let mut offset = line.floor_char_boundary(offset);
@@ -101,6 +101,9 @@ fn ceil_grapheme_cluster(
     offset: usize,
 ) -> Result<usize, Box<dyn Error>> {
     let mut offset = line.ceil_char_boundary(offset);
+    if offset == line.len() || line.byte(offset) < 128 {
+        return Ok(offset);
+    }
     write!(stdout(), "\x1b[G")?;
     line.slice(0, offset).print(&mut stdout())?;
     let (_, target_col) = term::cursor_pos(stdin)?;