reorder_characters

# File activesupport/lib/active_support/multibyte/handlers/utf8_handler.rb, line 466
      def reorder_characters(codepoints)
        length = codepoints.length- 1
        pos = 0
        while pos < length do
          cp1, cp2 = UCD[codepoints[pos]], UCD[codepoints[pos+1]]
          if (cp1.combining_class > cp2.combining_class) && (cp2.combining_class > 0)
            codepoints[pos..pos+1] = cp2.code, cp1.code
            pos += (pos > 0 ? -1 : 1)
          else
            pos += 1
          end
        end
        codepoints
      end