public boolean offer(T o) {
if (o == null) return false;
int incend = inc(end);
if (incend == start) {
setCapacity(elements.length * 2);
incend = inc(end);
}
elements[end] = o;
end = incend;
return true;
}
// Ensure that the array indexing starts at 0.
public void cleanup() {
if (start != 0) setCapacity(elements.length);
}
/* For cap elements, need an array of length at least cap+1 */
private void ensureCapacity(int cap) {
if (elements.length < cap + 1) {
setCapacity(cap * 2);
}
}