+void sunionDiffGenericCommand(redisClient *c, robj **setkeys, int setnum, robj *dstkey, int op);
+
+/* Factory method to return a set that *can* hold "value". When the object has
+ * an integer-encodable value, an intset will be returned. Otherwise a regular
+ * hash table. */
+robj *setTypeCreate(robj *value) {
+ if (isObjectRepresentableAsLongLong(value,NULL) == REDIS_OK)
+ return createIntsetObject();
+ return createSetObject();
+}
+
+int setTypeAdd(robj *subject, robj *value) {
+ long long llval;
+ if (subject->encoding == REDIS_ENCODING_HT) {
+ if (dictAdd(subject->ptr,value,NULL) == DICT_OK) {
+ incrRefCount(value);
+ return 1;
+ }
+ } else if (subject->encoding == REDIS_ENCODING_INTSET) {
+ if (isObjectRepresentableAsLongLong(value,&llval) == REDIS_OK) {
+ uint8_t success = 0;
+ subject->ptr = intsetAdd(subject->ptr,llval,&success);
+ if (success) {
+ /* Convert to regular set when the intset contains
+ * too many entries. */
+ if (intsetLen(subject->ptr) > server.set_max_intset_entries)
+ setTypeConvert(subject,REDIS_ENCODING_HT);
+ return 1;
+ }
+ } else {
+ /* Failed to get integer from object, convert to regular set. */
+ setTypeConvert(subject,REDIS_ENCODING_HT);
+
+ /* The set *was* an intset and this value is not integer
+ * encodable, so dictAdd should always work. */
+ redisAssertWithInfo(NULL,value,dictAdd(subject->ptr,value,NULL) == DICT_OK);
+ incrRefCount(value);
+ return 1;
+ }
+ } else {
+ redisPanic("Unknown set encoding");
+ }
+ return 0;
+}
+
+int setTypeRemove(robj *setobj, robj *value) {
+ long long llval;
+ if (setobj->encoding == REDIS_ENCODING_HT) {
+ if (dictDelete(setobj->ptr,value) == DICT_OK) {
+ if (htNeedsResize(setobj->ptr)) dictResize(setobj->ptr);
+ return 1;
+ }
+ } else if (setobj->encoding == REDIS_ENCODING_INTSET) {
+ if (isObjectRepresentableAsLongLong(value,&llval) == REDIS_OK) {
+ int success;
+ setobj->ptr = intsetRemove(setobj->ptr,llval,&success);
+ if (success) return 1;
+ }
+ } else {
+ redisPanic("Unknown set encoding");
+ }
+ return 0;
+}
+
+int setTypeIsMember(robj *subject, robj *value) {
+ long long llval;
+ if (subject->encoding == REDIS_ENCODING_HT) {
+ return dictFind((dict*)subject->ptr,value) != NULL;
+ } else if (subject->encoding == REDIS_ENCODING_INTSET) {
+ if (isObjectRepresentableAsLongLong(value,&llval) == REDIS_OK) {
+ return intsetFind((intset*)subject->ptr,llval);
+ }
+ } else {
+ redisPanic("Unknown set encoding");
+ }
+ return 0;
+}
+
+setTypeIterator *setTypeInitIterator(robj *subject) {
+ setTypeIterator *si = zmalloc(sizeof(setTypeIterator));
+ si->subject = subject;
+ si->encoding = subject->encoding;
+ if (si->encoding == REDIS_ENCODING_HT) {
+ si->di = dictGetIterator(subject->ptr);
+ } else if (si->encoding == REDIS_ENCODING_INTSET) {
+ si->ii = 0;
+ } else {
+ redisPanic("Unknown set encoding");
+ }
+ return si;
+}
+
+void setTypeReleaseIterator(setTypeIterator *si) {
+ if (si->encoding == REDIS_ENCODING_HT)
+ dictReleaseIterator(si->di);
+ zfree(si);
+}
+
+/* Move to the next entry in the set. Returns the object at the current
+ * position.
+ *
+ * Since set elements can be internally be stored as redis objects or
+ * simple arrays of integers, setTypeNext returns the encoding of the
+ * set object you are iterating, and will populate the appropriate pointer
+ * (eobj) or (llobj) accordingly.
+ *
+ * When there are no longer elements -1 is returned.
+ * Returned objects ref count is not incremented, so this function is
+ * copy on write friendly. */
+int setTypeNext(setTypeIterator *si, robj **objele, int64_t *llele) {
+ if (si->encoding == REDIS_ENCODING_HT) {
+ dictEntry *de = dictNext(si->di);
+ if (de == NULL) return -1;
+ *objele = dictGetKey(de);
+ } else if (si->encoding == REDIS_ENCODING_INTSET) {
+ if (!intsetGet(si->subject->ptr,si->ii++,llele))
+ return -1;
+ }
+ return si->encoding;
+}
+
+/* The not copy on write friendly version but easy to use version
+ * of setTypeNext() is setTypeNextObject(), returning new objects
+ * or incrementing the ref count of returned objects. So if you don't
+ * retain a pointer to this object you should call decrRefCount() against it.
+ *
+ * This function is the way to go for write operations where COW is not
+ * an issue as the result will be anyway of incrementing the ref count. */
+robj *setTypeNextObject(setTypeIterator *si) {
+ int64_t intele;
+ robj *objele;
+ int encoding;
+
+ encoding = setTypeNext(si,&objele,&intele);
+ switch(encoding) {
+ case -1: return NULL;
+ case REDIS_ENCODING_INTSET:
+ return createStringObjectFromLongLong(intele);
+ case REDIS_ENCODING_HT:
+ incrRefCount(objele);
+ return objele;
+ default:
+ redisPanic("Unsupported encoding");
+ }
+ return NULL; /* just to suppress warnings */
+}
+
+/* Return random element from a non empty set.
+ * The returned element can be a int64_t value if the set is encoded
+ * as an "intset" blob of integers, or a redis object if the set
+ * is a regular set.
+ *
+ * The caller provides both pointers to be populated with the right
+ * object. The return value of the function is the object->encoding
+ * field of the object and is used by the caller to check if the
+ * int64_t pointer or the redis object pointere was populated.
+ *
+ * When an object is returned (the set was a real set) the ref count
+ * of the object is not incremented so this function can be considered
+ * copy on write friendly. */
+int setTypeRandomElement(robj *setobj, robj **objele, int64_t *llele) {
+ if (setobj->encoding == REDIS_ENCODING_HT) {
+ dictEntry *de = dictGetRandomKey(setobj->ptr);
+ *objele = dictGetKey(de);
+ } else if (setobj->encoding == REDIS_ENCODING_INTSET) {
+ *llele = intsetRandom(setobj->ptr);
+ } else {
+ redisPanic("Unknown set encoding");
+ }
+ return setobj->encoding;
+}
+
+unsigned long setTypeSize(robj *subject) {
+ if (subject->encoding == REDIS_ENCODING_HT) {
+ return dictSize((dict*)subject->ptr);
+ } else if (subject->encoding == REDIS_ENCODING_INTSET) {
+ return intsetLen((intset*)subject->ptr);
+ } else {
+ redisPanic("Unknown set encoding");
+ }
+}
+
+/* Convert the set to specified encoding. The resulting dict (when converting
+ * to a hash table) is presized to hold the number of elements in the original
+ * set. */
+void setTypeConvert(robj *setobj, int enc) {
+ setTypeIterator *si;
+ redisAssertWithInfo(NULL,setobj,setobj->type == REDIS_SET &&
+ setobj->encoding == REDIS_ENCODING_INTSET);
+
+ if (enc == REDIS_ENCODING_HT) {
+ int64_t intele;
+ dict *d = dictCreate(&setDictType,NULL);
+ robj *element;
+
+ /* Presize the dict to avoid rehashing */
+ dictExpand(d,intsetLen(setobj->ptr));
+
+ /* To add the elements we extract integers and create redis objects */
+ si = setTypeInitIterator(setobj);
+ while (setTypeNext(si,NULL,&intele) != -1) {
+ element = createStringObjectFromLongLong(intele);
+ redisAssertWithInfo(NULL,element,dictAdd(d,element,NULL) == DICT_OK);
+ }
+ setTypeReleaseIterator(si);
+
+ setobj->encoding = REDIS_ENCODING_HT;
+ zfree(setobj->ptr);
+ setobj->ptr = d;
+ } else {
+ redisPanic("Unsupported set conversion");
+ }
+}
+