{
    ($len       or last) and $a+= $k[0];
    ($len >=  2 or last) and $a+= $k[1]  <<8;
    ($len >=  3 or last) and $a+= $k[2]  <<16;
    ($len >=  4 or last) and $a+= $k[3]  <<24;
    ($len >=  5 or last) and $b+= $k[4];
    ($len >=  6 or last) and $b+= $k[5]  <<8;
    ($len >=  7 or last) and $b+= $k[6]  <<16;
    ($len >=  8 or last) and $b+= $k[7]  <<24;
    ($len >=  9 or last) and $c+= $k[8]  <<8;
    ($len >= 10 or last) and $c+= $k[9]  <<16;
    ($len >= 11 or last) and $c+= $k[10] <<24;
}