详解Redis如何处理Hash冲突

typedef struct dictht {
    dictEntry **table;  // 哈希表数组
    unsigned long size; // 哈希表大小
    unsigned long sizemask; // 哈希表大小掩码，用于计算索引
    unsigned long used; // 已使用的哈希表节点数量
} dictht;

typedef struct dictEntry {
    void *key; // 键
    union {
        void *val; // 值
        uint64_t u64;
        int64_t s64;
        double d;
    } v;
    struct dictEntry *next; // 指向下一个哈希表节点，形成链表
} dictEntry;

function dictAdd(dict, key, value):
    index = hashFunction(key) & dict.sizemask
    if dict.table[index] == NULL:
        dict.table[index] = new dictEntry(key, value)
    else:
        newEntry = new dictEntry(key, value)
        newEntry.next = dict.table[index]
        dict.table[index] = newEntry

function dictFind(dict, key):
    index = hashFunction(key) & dict.sizemask
    entry = dict.table[index]
    while entry != NULL:
        if entry.key == key:
            return entry.value
        entry = entry.next
    return NULL

function rehashStep(dict):
    if dict.rehashidx == -1:
        return
    for i = 0 to REHASH_BATCH_SIZE:
        if dict.rehashidx >= dict.size:
            dict.rehashidx = -1
            break
        while dict.table[dict.rehashidx] == NULL:
            dict.rehashidx += 1
        entry = dict.table[dict.rehashidx]
        while entry != NULL:
            nextEntry = entry.next
            index = hashFunction(entry.key) & dict.new_ht.sizemask
            entry.next = dict.new_ht.table[index]
            dict.new_ht.table[index] = entry
            entry = nextEntry
        dict.table[dict.rehashidx] = NULL
        dict.rehashidx += 1