Function geoGetPointsInRange

src/geo.cpp:255–316

Query a Redis sorted set to extract all the elements between 'min' and * 'max', appending them into the array of geoPoint structures 'gparray'. * The command returns the number of elements added to the array. * * Elements which are farest than 'radius' from the specified 'x' and 'y' * coordinates are not included. * * The ability of this function to append to an existing set of points is *

 * via qsort. Similarly we need to be able to reject points outside the search
 * radius area ASAP in order to allocate and process more points than needed. */
int geoGetPointsInRange(robj_roptr zobj, double min, double max, GeoShape *shape, geoArray *ga, unsigned long limit) {
    /* minex 0 = include min in range; maxex 1 = exclude max in range */
    /* That's: min <= val < max */
    zrangespec range = { min, max, 0, 1 };
    size_t origincount = ga->used;
    sds member;

    if (zobj->encoding == OBJ_ENCODING_ZIPLIST) {
        unsigned char *zl = (unsigned char*)zobj->m_ptr;
        unsigned char *eptr, *sptr;
        unsigned char *vstr = NULL;
        unsigned int vlen = 0;
        long long vlong = 0;
        double score = 0;

        if ((eptr = zzlFirstInRange(zl, &range)) == NULL) {
            /* Nothing exists starting at our min.  No results. */
            return 0;
        }

        sptr = ziplistNext(zl, eptr);
        while (eptr) {
            score = zzlGetScore(sptr);

            /* If we fell out of range, break. */
            if (!zslValueLteMax(score, &range))
                break;

            /* We know the element exists. ziplistGet should always succeed */
            ziplistGet(eptr, &vstr, &vlen, &vlong);
            member = (vstr == NULL) ? sdsfromlonglong(vlong) :
                                      sdsnewlen(vstr,vlen);
            if (geoAppendIfWithinShape(ga,shape,score,member)
                == C_ERR) sdsfree(member);
            if (ga->used && limit && ga->used >= limit) break;
            zzlNext(zl, &eptr, &sptr);
        }
    } else if (zobj->encoding == OBJ_ENCODING_SKIPLIST) {
        zset *zs = (zset*)zobj->m_ptr;
        zskiplist *zsl = zs->zsl;
        zskiplistNode *ln;

        if ((ln = zslFirstInRange(zsl, &range)) == NULL) {
            /* Nothing exists starting at our min.  No results. */
            return 0;
        }

        while (ln) {
            sds ele = ln->ele;
            /* Abort when the node is no longer in range. */
            if (!zslValueLteMax(ln->score, &range))
                break;

            ele = sdsdup(ele);
            if (geoAppendIfWithinShape(ga,shape,ln->score,ele)
                == C_ERR) sdsfree(ele);
            if (ga->used && limit && ga->used >= limit) break;
            ln = ln->level(0)->forward;