Laravel与CI框架中截取字符串函数

Laravel：

    function limit($value, $limit = 100, $end = '...')
    {
      if (mb_strwidth($value, 'UTF-8') <= $limit) {
        return $value;
      }

      return rtrim(mb_strimwidth($value, 0, $limit, '', 'UTF-8')).$end;
    }

Ci：

    function word_limiter($str, $limit = 100, $end_char = '…')
    {
      if (trim($str) === '')
      {
        return $str;
      }

      preg_match('/^\s*+(?:\S++\s*+){1,'.(int) $limit.'}/', $str, $matches);

      if (strlen($str) === strlen($matches[0]))
      {
        $end_char = '';
      }

      return rtrim($matches[0]).$end_char;
    }