escape

# File lib/uri/rfc2396_parser.rb, line 300
    def escape(str, unsafe = @regexp[:UNSAFE])
      unless unsafe.kind_of?(Regexp)
        # perhaps unsafe is String object
        unsafe = Regexp.new("[#{Regexp.quote(unsafe)}]", false)
      end
      str.gsub(unsafe) do
        us = $&
        tmp = ''
        us.each_byte do |uc|
          tmp << sprintf('%%%02X', uc)
        end
        tmp
      end.force_encoding(Encoding::US_ASCII)
    end