function processing(domain_name, useSTD3, processing_option) {
  var result = mapChars(domain_name, useSTD3, processing_option);
  result.string = normalize(result.string);

  var labels = result.string.split(".");
  for (var i = 0; i < labels.length; ++i) {
    try {
      var validation = validateLabel(labels[i]);
      labels[i] = validation.label;
      result.error = result.error || validation.error;
    } catch(e) {
      result.error = true;
    }
  }

  return {
    string: labels.join("."),
    error: result.error
  };
}
Check if `expected` mime type
matches `actual` mime type with
wildcard and +suffix support.

@param {String} expected
@param {String} actual
@return {Boolean}
@private