Function hashTypeRandomElement

src/t_hash.cpp:620–636

Return random element from a non empty hash. * 'key' and 'val' will be set to hold the element. * The memory in them is not to be freed or modified by the caller. * 'val' can be NULL in which case it's not extracted. */

 * The memory in them is not to be freed or modified by the caller.
 * 'val' can be NULL in which case it's not extracted. */
void hashTypeRandomElement(robj_roptr hashobj, unsigned long hashsize, ziplistEntry *key, ziplistEntry *val) {
    if (hashobj->encoding == OBJ_ENCODING_HT) {
        dictEntry *de = dictGetFairRandomKey((dict*)ptrFromObj(hashobj));
        sds s = (sds)dictGetKey(de);
        key->sval = (unsigned char*)s;
        key->slen = sdslen(s);
        if (val) {
            sds s = (sds)dictGetVal(de);
            val->sval = (unsigned char*)s;
            val->slen = sdslen(s);
        }
    } else if (hashobj->encoding == OBJ_ENCODING_ZIPLIST) {
        ziplistRandomPair((unsigned char*)ptrFromObj(hashobj), hashsize, key, val);
    } else {
        serverPanic("Unknown hash encoding");
    }
}


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