code: public LinkedList<Diff> diff_main(String text1, String text2,
              boolean checklines) {
          // Set a deadline by which time the diff must be complete.
          long deadline;
          if (Diff_Timeout <= 0) {
              deadline = Long.MAX_VALUE;
          } else {
              deadline = System.currentTimeMillis()
                      + (long) (Diff_Timeout * 1000);
          }
          return diff_main(text1, text2, checklines, deadline);
      }
docs: Find the differences between two texts.
  
  @param text1
  Old string to be diffed.
  @param text2
  New string to be diffed.
  @param checklines
  Speedup flag. If false, then don't run a line-level diff first
  to identify the changed areas. If true, then run a faster
  slightly less optimal diff.
  @return Linked List of Diff objects.