Function zsetConvertToZiplistIfNeeded

src/t_zset.cpp:1249–1257

Convert the sorted set object into a ziplist if it is not already a ziplist * and if the number of elements and the maximum element size and total elements size * are within the expected ranges. */

 * and if the number of elements and the maximum element size and total elements size
 * are within the expected ranges. */
void zsetConvertToZiplistIfNeeded(robj *zobj, size_t maxelelen, size_t totelelen) {
    if (zobj->encoding == OBJ_ENCODING_ZIPLIST) return;
    zset *set = (zset*)zobj->m_ptr;

    if (set->zsl->length <= g_pserver->zset_max_ziplist_entries &&
        maxelelen <= g_pserver->zset_max_ziplist_value &&
        ziplistSafeToAdd(NULL, totelelen))
            zsetConvert(zobj,OBJ_ENCODING_ZIPLIST);
}

/* Return (by reference) the score of the specified member of the sorted set
 * storing it into *score. If the element does not exist C_ERR is returned