class Mail::Parsers::ContentDispositionParser

def cleaned(string)
  string =~ /(.+);\s*$/ ? $1 : string
end

def parse(s)
  content_disposition = ContentDispositionStruct.new("", nil)
  if s.blank?
    return content_disposition
  end
  actions, error = Ragel.parse(:content_disposition, s)
  if error
    raise Mail::Field::ParseError.new(Mail::ContentDispositionElement, s, error)
  end
  content_disposition.parameters = []
  disp_type_s = param_attr_s = param_attr = qstr_s = qstr = param_val_s = nil
  actions.each_slice(2) do |action_id, p|
    action = Mail::Parsers::Ragel::ACTIONS[action_id]
    case action
    # Disposition Type
    when :disp_type_s then disp_type_s = p
    when :disp_type_e
      content_disposition.disposition_type = s[disp_type_s..(p-1)].downcase
    # Parameter Attribute
    when :param_attr_s then param_attr_s = p
    when :param_attr_e then param_attr = s[param_attr_s..(p-1)]
    # Quoted String.
    when :qstr_s then qstr_s = p
    when :qstr_e then qstr = s[qstr_s..(p-1)]
    # Parameter Value
    when :param_val_s then param_val_s = p
    when :param_val_e
      if param_attr.nil?
        raise Mail::Field::ParseError.new(Mail::ContentDispositionElement, s, "no attribute for value")
      end
      # Use quoted string value if one exists, otherwise use parameter value
      if qstr
        value = qstr
      else
        value = s[param_val_s..(p-1)]
      end
      content_disposition.parameters <<  { param_attr => value }
      param_attr = nil
      qstr = nil
    else
      raise Mail::Field::ParseError.new(Mail::ContentDispositionElement, s, "Failed to process unknown action: #{action}")
    end
  end
  content_disposition
end