【Redis 系列】redis 学习十六，redis 字典(map) 及其核心编码结构

/* Redis database representation. There are multiple databases identified
 * by integers from 0 (the default database) up to the max configured
 * database. The database number is the 'id' field in the structure. */
typedef struct redisDb {
    dict *dict;                 /* The keyspace for this DB */
    dict *expires;              /* Timeout of keys with a timeout set */
    dict *blocking_keys;        /* Keys with clients waiting for data (BLPOP)*/
    dict *ready_keys;           /* Blocked keys that received a PUSH */
    dict *watched_keys;         /* WATCHED keys for MULTI/EXEC CAS */
    int id;                     /* Database ID */
    long long avg_ttl;          /* Average TTL, just for stats */
    unsigned long expires_cursor; /* Cursor of the active expire cycle. */
    list *defrag_later;         /* List of key names to attempt to defrag one by one, gradually. */
} redisDb;

typedef struct dict {
    dictType *type;
    void *privdata;
    dictht ht[2];
    long rehashidx; /* rehashing not in progress if rehashidx == -1 */
    int16_t pauserehash; /* If >0 rehashing is paused (<0 indicates coding error) */
} dict;

typedef struct dictType {
    uint64_t (*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);
    int (*expandAllowed)(size_t moreMem, double usedRatio);
} 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 dictEntry {
    void *key;
    union {
        void *val;
        uint64_t u64;
        int64_t s64;
        double d;
    } v;
    struct dictEntry *next;
} dictEntry;

typedef struct redisObject {
    unsigned type:4;
    unsigned encoding:4;
    unsigned lru:LRU_BITS; /* LRU time (relative to global lru_clock) or
                            * LFU data (least significant 8 bits frequency
                            * and most significant 16 bits access time). */
    int refcount;
    void *ptr;
} robj;

127.0.0.1:6379> SETBIT login:9:11 25 1
(integer) 0
127.0.0.1:6379> SETBIT login:9:11 26 1
(integer) 0
127.0.0.1:6379> SETBIT login:9:11 27 1
(integer) 0
127.0.0.1:6379> BITCOUNT login:9:11
(integer) 3
127.0.0.1:6379> strlen login:9:11
(integer) 4

127.0.0.1:6379> SETBIT login:9:12 26 1
(integer) 0
127.0.0.1:6379> SETBIT login:9:12 25 0
(integer) 0
127.0.0.1:6379> SETBIT login:9:12 27 1
(integer) 0
127.0.0.1:6379> STRLEN login:9:12
(integer) 4

127.0.0.1:6379> BITOP and login:and login:9:11 login:9:12
(integer) 4
127.0.0.1:6379> BITCOUNT login:and
(integer) 2

127.0.0.1:6379> BITOP or login:or login:9:11 login:9:12
(integer) 4
127.0.0.1:6379> BITCOUNT login:or
(integer) 3

127.0.0.1:6379> type login:or
string
127.0.0.1:6379> OBJECT encoding login:or
"raw"
127.0.0.1:6379> OBJECT encoding login:9:12
"raw"
127.0.0.1:6379> OBJECT encoding login:and
"raw"

127.0.0.1:6379> set name xiaoming
OK
127.0.0.1:6379> OBJECT encoding name
"embstr"

127.0.0.1:6379> set test 99999999991111111111222222222233333333334444
OK
127.0.0.1:6379> OBJECT encoding test
"embstr"
127.0.0.1:6379> STRLEN test
(integer) 44

127.0.0.1:6379> set test2 999999999911111111112222222222333333333344449
OK
127.0.0.1:6379> OBJECT encoding test2
"raw"