I need to convert septets to octest like this c example:
private void septetToOctet()
{
    int len = 1;
    int j = 0;
    int septetcount = septet.Count;
    while (j < septet.Count - 1)
    {
        string tmp = septet[j]; // storing jth value
        string tmp1 = septet[j + 1]; //storing j+1 th value
        string mid = SWAP(tmp1);
        tmp1 = mid;
        tmp1 = tmp1.Substring(0, len);
        string add = SWAP(tmp1);
        tmp = add + tmp;// +"-";
        tmp = tmp.Substring(0, 8);
        //txtoctet.Text += tmp + " || ";
        octet.Add(tmp);
        len++;
        if (len == 8)
        {
            len = 1;
            j = j + 1;
        }
        j = j + 1;
    }
}
..only problem is - i need to do it in php. Does anybody have an code example for this ?