Fixing unreachable condition.

  if (!isMultiLine) at line 563 suggests that isMultiline is 0 when if takes true branch. So the condition && at line 571 will always be false.
Also at line 568 !isMultiline in loop conditional check suggests that it depends only on one condition i.e. index <size because !isMultiline is always true. 
Hence , it seems logical mistake at line 571 of using && instead of ||