void zlexcountCommand(client *c) {
    robj *key = c->argv[1];
    robj *zobj;
    zlexrangespec range;
    unsigned long count = 0;

    /* Parse the range arguments */
    if (zslParseLexRange(c->argv[2],c->argv[3],&range) != C_OK) {
        addReplyError(c,"min or max not valid string range item");
        return;
    }

    /* Lookup the sorted set */
    if ((zobj = lookupKeyReadOrReply(c, key, shared.czero)) == NULL ||
        checkType(c, zobj, OBJ_ZSET))
    {
        zslFreeLexRange(&range);
        return;
    }

    if (zobj->encoding == OBJ_ENCODING_ZIPLIST) {
        unsigned char *zl = zobj->ptr;
        unsigned char *eptr, *sptr;

        /* Use the first element in range as the starting point */
        eptr = zzlFirstInLexRange(zl,&range);

        /* No "first" element */
        if (eptr == NULL) {
            zslFreeLexRange(&range);
            addReply(c, shared.czero);
            return;
        }

        /* First element is in range */
        sptr = ziplistNext(zl,eptr);
        serverAssertWithInfo(c,zobj,zzlLexValueLteMax(eptr,&range));

        /* Iterate over elements in range */
        while (eptr) {
            /* Abort when the node is no longer in range. */
            if (!zzlLexValueLteMax(eptr,&range)) {
                break;
            } else {
                count++;
                zzlNext(zl,&eptr,&sptr);
            }
        }
    } else if (zobj->encoding == OBJ_ENCODING_SKIPLIST) {
        zset *zs = zobj->ptr;
        zskiplist *zsl = zs->zsl;
        zskiplistNode *zn;
        unsigned long rank;

        /* Find first element in range */
        zn = zslFirstInLexRange(zsl, &range);

        /* Use rank of first element, if any, to determine preliminary count */
        if (zn != NULL) {
            rank = zslGetRank(zsl, zn->score, zn->ele);
            count = (zsl->length - (rank - 1));

            /* Find last element in range */
            zn = zslLastInLexRange(zsl, &range);

            /* Use rank of last element, if any, to determine the actual count */
            if (zn != NULL) {
                rank = zslGetRank(zsl, zn->score, zn->ele);
                count -= (zsl->length - rank);
            }
        }
    } else {
        serverPanic("Unknown sorted set encoding");
    }

    zslFreeLexRange(&range);
    addReplyLongLong(c, count);
}
void zlexcountCommand(client *c) {
    robj *key = c->argv[1];
    robj *zobj;
    zlexrangespec range;
    unsigned long count = 0;

     
    if (zslParseLexRange(c->argv[2],c->argv[3],&range) != C_OK) {
        addReplyError(c,"min or max not valid string range item");
        return;
    }

     
    if ((zobj = lookupKeyReadOrReply(c, key, shared.czero)) == NULL ||
        checkType(c, zobj, OBJ_ZSET))
    {
        zslFreeLexRange(&range);
        return;
    }

    if (zobj->encoding == OBJ_ENCODING_ZIPLIST) {
        unsigned char *zl = zobj->ptr;
        unsigned char *eptr, *sptr;

         
        eptr = zzlFirstInLexRange(zl,&range);

         
        if (eptr == NULL) {
            zslFreeLexRange(&range);
            addReply(c, shared.czero);
            return;
        }

         
        sptr = ziplistNext(zl,eptr);
        serverAssertWithInfo(c,zobj,zzlLexValueLteMax(eptr,&range));

         
        while (eptr) {
             
            if (!zzlLexValueLteMax(eptr,&range)) {
                break;
            } else {
                count++;
                zzlNext(zl,&eptr,&sptr);
            }
        }
    } else if (zobj->encoding == OBJ_ENCODING_SKIPLIST) {
        zset *zs = zobj->ptr;
        zskiplist *zsl = zs->zsl;
        zskiplistNode *zn;
        unsigned long rank;

         
        zn = zslFirstInLexRange(zsl, &range);

         
        if (zn != NULL) {
            rank = zslGetRank(zsl, zn->score, zn->ele);
            count = (zsl->length - (rank - 1));

             
            zn = zslLastInLexRange(zsl, &range);

             
            if (zn != NULL) {
                rank = zslGetRank(zsl, zn->score, zn->ele);
                count -= (zsl->length - rank);
            }
        }
    } else {
        serverPanic("Unknown sorted set encoding");
    }

    zslFreeLexRange(&range);
    addReplyLongLong(c, count);
}