SFQ_EMPTY_SLOT
q->ht[slot->hash] = SFQ_EMPTY_SLOT;
if (x == SFQ_EMPTY_SLOT) {
q->ht[slot->hash] = SFQ_EMPTY_SLOT;
q->ht[slot->hash] = SFQ_EMPTY_SLOT;
if (x == SFQ_EMPTY_SLOT) {
q->ht[i] = SFQ_EMPTY_SLOT;
if (idx != SFQ_EMPTY_SLOT) {
if (q->ht[i] == SFQ_EMPTY_SLOT) {