PHP - 准确计算过了多少个周几

如下

---

    /**
     * 获取从星期($dayStartOfMonth)在过了$daysInMonth后共过了多少个$day
     *
     * @param [type] $daysInMonth 
     * @param [type] $day
     * @param [type] $dayStartOfMonth date('w',strtotime(date('Y-m-1')))
     * @return void
     */
    protected function dayNumOfPassDays($daysInMonth, $day, $dayStartOfMonth)
    {
        $num = 0;
        $j = $dayStartOfMonth;
        for ($i=1; $i<=$daysInMonth;$i++) {
            if ($j == $day) {
                $num++;
            }
            $j++;
            if ($j%8 == 0) {
                $j=1;
            }
        }
        return $num;
    }