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;
}