voku / portable-utf8

   *

   * @return   string The string with unwanted characters stripped from the right

   */

  public static function rtrim($string = '', $chars = INF)

  {

    $string = (string)$string;

    if (!isset($string[0])) {

      return '';

    }

    $chars = INF === $chars ? '\s' : self::rxClass($chars);

    return preg_replace("/{$chars}+$/u", '', $string);

  }

  /**

   * strip whitespace or other characters from beginning of a UTF-8 string

   *

   * @return   string The string with unwanted characters stripped from the left

   */

  public static function ltrim($string = '', $chars = INF)

  {

    $string = (string)$string;

    if (!isset($string[0])) {

      return '';

    }

    $chars = INF === $chars ? '\s' : self::rxClass($chars);

    return preg_replace("/^{$chars}+/u", '', $string);

  }

  /**

   * Replace text within a portion of a string