[code] iterators all the way

src/main.rs

@@ -45,12 +45,10 @@ where
 
 fn trim_end(line: &[u8]) -> usize {
     let mut end = line.len();
-    for ch in line.iter().rev() {
-        if *ch != b'\r' && *ch != b'\n' && *ch != b'\t' {
-            break;
-        }
-        end -= 1;
-    }
+    line.iter()
+        .rev()
+        .take_while(|ch| ch.is_ascii_whitespace())
+        .for_each(|_| end -= 1);
     end
 }