wrap_optimal_fit() - Checked arithmetic

src/lib.rs

@@ -1851,6 +1851,11 @@ mod tests {
  );
  }
 
+ #[test]
+ fn fill_large_width() {
+ fill("!@", 18446743798827450368);
+ }
+
  #[test]
  #[cfg(not(feature = "smawk"))]
  #[cfg(not(feature = "unicode-linebreak"))]

src/wrap_algorithms/optimal_fit.rs

@@ -272,7 +272,7 @@ pub fn wrap_optimal_fit<'a, 'b, T: Fragment>(
  // breaking before fragments[i].
  //
  // First, every extra line cost NLINE_PENALTY.
- let mut cost = minima[i].1 + penalties.nline_penalty;
+ let mut cost = (minima[i].1 as i32).saturating_add(penalties.nline_penalty);
 
  // Next, we add a penalty depending on the line length.
  if line_width > target_width {
@@ -283,12 +283,12 @@ pub fn wrap_optimal_fit<'a, 'b, T: Fragment>(
  // Other lines (except for the last line) get a milder
  // penalty which depend on the size of the gap.
  let gap = (target_width - line_width) as i32;
- cost += gap * gap;
+ cost = cost.saturating_add(gap.saturating_mul(gap));
  } else if i + 1 == j && line_width < target_width / penalties.short_last_line_fraction {
  // The last line can have any size gap, but we do add a
  // penalty if the line is very short (typically because it
  // contains just a single word).
- cost += penalties.short_last_line_penalty;
+ cost = cost.saturating_add(penalties.short_last_line_penalty);
  }
 
  // Finally, we discourage hyphens.