typedef struct dictEntry {void *key;union {void *val;uint64_t u64;int64_t s64;double d;} v;struct dictEntry *next;
} dictEntry;typedef struct dictType {unsigned int (*hashFunction)(const void *key);void *(*keyDup)(void *privdata, const void *key);void *(*valDup)(void *privdata, const void *obj);int (*keyCompare)(void *privdata, const void *key1, const void *key2);void (*keyDestructor)(void *privdata, void *key);void (*valDestructor)(void *privdata, void *obj);
} dictType;/* This is our hash table structure. Every dictionary has two of this as we* implement incremental rehashing, for the old to the new table. */
typedef struct dictht {dictEntry **table;unsigned long size;unsigned long sizemask;unsigned long used;
} dictht;typedef struct dict {dictType *type;void *privdata;dictht ht[2];long rehashidx; /* rehashing not in progress if rehashidx == -1 */int iterators; /* number of iterators currently running */
} dict;/* If safe is set to 1 this is a safe iterator, that means, you can call* dictAdd, dictFind, and other functions against the dictionary even while* iterating. Otherwise it is a non safe iterator, and only dictNext()* should be called while iterating. */
typedef struct dictIterator {dict *d;long index;int table, safe;dictEntry *entry, *nextEntry;/* unsafe iterator fingerprint for misuse detection. */long long fingerprint;
} dictIterator;typedef void (dictScanFunction)(void *privdata, const dictEntry *de);

dictEntry *dictFind(dict *d, const void *key)
{dictEntry *he;unsigned int h, idx, table;if (d->ht[0].size == 0) return NULL; /* We don't have a table at all */if (dictIsRehashing(d)) _dictRehashStep(d);h = dictHashKey(d, key);for (table = 0; table <= 1; table++) {idx = h & d->ht[table].sizemask;he = d->ht[table].table[idx];while(he) {if (dictCompareKeys(d, key, he->key))return he;he = he->next;}if (!dictIsRehashing(d)) return NULL;}return NULL;
}

int dictRehash(dict *d, int n) {int empty_visits = n*10; /* Max number of empty buckets to visit. */if (!dictIsRehashing(d)) return 0;while(n-- && d->ht[0].used != 0) {dictEntry *de, *nextde;/* Note that rehashidx can't overflow as we are sure there are more* elements because ht[0].used != 0 */assert(d->ht[0].size > (unsigned long)d->rehashidx);while(d->ht[0].table[d->rehashidx] == NULL) {d->rehashidx++;if (--empty_visits == 0) return 1;}de = d->ht[0].table[d->rehashidx];/* Move all the keys in this bucket from the old to the new hash HT */while(de) {unsigned int h;nextde = de->next;/* Get the index in the new hash table */h = dictHashKey(d, de->key) & d->ht[1].sizemask;de->next = d->ht[1].table[h];d->ht[1].table[h] = de;d->ht[0].used--;d->ht[1].used++;de = nextde;}d->ht[0].table[d->rehashidx] = NULL;d->rehashidx++;}/* Check if we already rehashed the whole table... */if (d->ht[0].used == 0) {zfree(d->ht[0].table);d->ht[0] = d->ht[1];_dictReset(&d->ht[1]);d->rehashidx = -1;return 0;}/* More to rehash... */return 1;
}

dictEntry *dictNext(dictIterator *iter)
{//对表的桶进行遍历，直到找到一个非空桶，返回while (1) {if (iter->entry == NULL) {dictht *ht = &iter->d->ht[iter->table];if (iter->index == -1 && iter->table == 0) {if (iter->safe)iter->d->iterators++;elseiter->fingerprint = dictFingerprint(iter->d);//对dict进行指纹
            }iter->index++;//如果迭代到表的最后一个桶，就判断要不要迭代第二个表if (iter->index >= (long) ht->size) {if (dictIsRehashing(iter->d) && iter->table == 0) {iter->table++;iter->index = 0;ht = &iter->d->ht[1];} else {break;}}iter->entry = ht->table[iter->index];} else {iter->entry = iter->nextEntry;}if (iter->entry) {/* We need to save the 'next' here, the iterator user* may delete the entry we are returning. */iter->nextEntry = iter->entry->next;return iter->entry;}}return NULL;
}

/* API */
/* 字典创建， type参数制定各类对字典的自定义函数，会初始化dictht, dict */
dict *dictCreate(dictType *type, void *privDataPtr);
int dictExpand(dict *d, unsigned long size);
/* 添加键值对，内部调用addRaw和setvalue ，如果已经存在，返回NULL*/
int dictAdd(dict *d, void *key, void *val);
/* 添加键 ，如果已经存在，返回NULL*/
dictEntry *dictAddRaw(dict *d, void *key);
/* 添加一个key,如果存在，直接设置value,设置key的value */
int dictReplace(dict *d, void *key, void *val);
/* 添加一个key,如果存在，直接返回 */
dictEntry *dictReplaceRaw(dict *d, void *key);
/* 删除一个节点，需要free那个节点 */
int dictDelete(dict *d, const void *key);
/* 删除一个节点，不需要free那个节点 */
int dictDeleteNoFree(dict *d, const void *key);
/* 删除dict*/
void dictRelease(dict *d);
/* 查找key*/
dictEntry * dictFind(dict *d, const void *key);
/* 查找key的value*/
void *dictFetchValue(dict *d, const void *key);
/* 将dict的size设置和元素数量一样，但是符合2的倍数*/
int dictResize(dict *d);
dictIterator *dictGetIterator(dict *d);
dictIterator *dictGetSafeIterator(dict *d);
dictEntry *dictNext(dictIterator *iter);
void dictReleaseIterator(dictIterator *iter);
dictEntry *dictGetRandomKey(dict *d);
unsigned int dictGetSomeKeys(dict *d, dictEntry **des, unsigned int count);
void dictPrintStats(dict *d);
unsigned int dictGenHashFunction(const void *key, int len);
unsigned int dictGenCaseHashFunction(const unsigned char *buf, int len);
void dictEmpty(dict *d, void(callback)(void*));
void dictEnableResize(void);
void dictDisableResize(void);
int dictRehash(dict *d, int n);
/* rehash，设置一个最长时间*/
int dictRehashMilliseconds(dict *d, int ms);
void dictSetHashFunctionSeed(unsigned int initval);
unsigned int dictGetHashFunctionSeed(void);
unsigned long dictScan(dict *d, unsigned long v, dictScanFunction *fn, void *privdata);