+/* Delete all the elements with score between min and max from the skiplist.
+ * Min and mx are inclusive, so a score >= min || score <= max is deleted.
+ * Note that this function takes the reference to the hash table view of the
+ * sorted set, in order to remove the elements from the hash table too. */
+static unsigned long zslDeleteRange(zskiplist *zsl, double min, double max, dict *dict) {
+ zskiplistNode *update[ZSKIPLIST_MAXLEVEL], *x;
+ unsigned long removed = 0;
+ int i;
+
+ x = zsl->header;
+ for (i = zsl->level-1; i >= 0; i--) {
+ while (x->forward[i] && x->forward[i]->score < min)
+ x = x->forward[i];
+ update[i] = x;
+ }
+ /* We may have multiple elements with the same score, what we need
+ * is to find the element with both the right score and object. */
+ x = x->forward[0];
+ while (x && x->score <= max) {
+ zskiplistNode *next;
+
+ for (i = 0; i < zsl->level; i++) {
+ if (update[i]->forward[i] != x) break;
+ update[i]->forward[i] = x->forward[i];
+ }
+ if (x->forward[0]) {
+ x->forward[0]->backward = (x->backward == zsl->header) ?
+ NULL : x->backward;
+ } else {
+ zsl->tail = x->backward;
+ }
+ next = x->forward[0];
+ dictDelete(dict,x->obj);
+ zslFreeNode(x);
+ while(zsl->level > 1 && zsl->header->forward[zsl->level-1] == NULL)
+ zsl->level--;
+ zsl->length--;
+ removed++;
+ x = next;
+ }
+ return removed; /* not found */
+}
+