check_encoding (REXML::Encoding)

    # File temp/encoding.rb, line 57
        def check_encoding str
          # We have to recognize UTF-16, LSB UTF-16, and UTF-8
          if str[0,2] == "\xfe\xff"
            str[0,2] = ""
            return UTF_16
          elsif str[0,2] == "\xff\xfe"
            str[0,2] = ""
            return UNILE
          end
          str =~ /^\s*<\?xml\s+version\s*=\s*(['"]).*?\1\s+encoding\s*=\s*(["'])(.*?)\2/m
          return $3.upcase if $3
          return UTF_8
        end