dict是redis中的基本數據結構，源碼中是通過hash表來實現的。項目將挑選幾個主要函數和大家分享下redis源碼的簡潔。

先看dict的數據結構如下

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;


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 */
    unsigned long iterators; /* number of iterators currently running */
} dict;

 

type是hash表的內置函數，包括計算hash key，比較hash key等等。
ht[2]中的每個元素表示一張hash表。

redis源碼閱讀筆記----dict.c