Results

   */
  public function buildForm(array $form, FormStateInterface $form_state) {
    if (Unicode::getStatus() !== Unicode::STATUS_MULTIBYTE) {
      drupal_set_message($this->t('This version of PHP does not support multibyte encodings.'), 'error');
      return $form;
    }

    $form['intro'] = [
      '#markup' => $this->t("Specify the contents to migrate and the path to the UseBB installation and click 'Start migration'. Existing Drupal content and users will not be modified or removed. Additionally, provide the public URLs to the UseBB forum so that internal links can be translated."),

    PREG_CLASS_UNICODE_WORD_BOUNDARY: '\Drupal\Component\Utility\Unicode::PREG_CLASS_WORD_BOUNDARY'
    UNICODE_ERROR: '\Drupal\Component\Utility\Unicode::STATUS_ERROR'
    UNICODE_MULTIBYTE: '\Drupal\Component\Utility\Unicode::STATUS_MULTIBYTE'
    UNICODE_SINGLEBYTE: '\Drupal\Component\Utility\Unicode::STATUS_SINGLEBYTE'

  public function __construct(array $encoding_list) {
    $this->encodingList = $encoding_list;
    $this->isMultibyte = Unicode::getStatus() == Unicode::STATUS_MULTIBYTE;
  }

  /**
   * {@inheritdoc}
   */
  public function convertEncoding($data) {

    $input = $request->query->get('q');

    if (!strlen($input) || Unicode::getStatus() != Unicode::STATUS_MULTIBYTE) {
      return new JsonResponse($matches);
    }

    $added = array_map('trim', explode(',', $input));
    $input = array_pop($added);
    $lower_added = array_map('mb_strtolower', $added);

    $is_multibyte = (Unicode::getStatus() == Unicode::STATUS_MULTIBYTE) ? TRUE : FALSE;
    if ($this->getSetting(self::CASE_SENSITIVE)) {
      // The text to look for must match uppercase or lowercase characters.
      return $is_multibyte ? 'mb_strpos' : 'strpos';
    }

    // The text search is case-insensitive.