new length=strlen(buf);
new s1 = 1;
new s2 = 0;
new n;
for (n=0; n<length; n++)
{
    s1 = (s1 + buf[n]) % 65521;
    s2 = (s2 + s1)     % 65521;
}
return (s2 << 16) + s1;