# File lib/soap/generator.rb, line 194
  def encode_string(str)
    if @use_numeric_character_reference and !XSD::Charset.is_us_ascii(str)
      str.gsub!(EncodeCharRegexp) { |c| EncodeMap[c] }
      @buf << str.unpack("U*").collect { |c|
        if c == 0x9 or c == 0xa or c == 0xd or (c >= 0x20 and c <= 0x7f)
          c.chr
        else
          sprintf("&#x%x;", c)
        end
      }.join
    else
      @buf << str.gsub(EncodeCharRegexp) { |c| EncodeMap[c] }
    end
  end