union_dbscan_minpoints_1()

static int union_dbscan_minpoints_1 ( LWGEOM **  geoms, uint32_t  num_geoms, UNIONFIND *  uf, double  eps, char **  in_a_cluster_ret  )

static

Definition at line 314 of file lwgeom_geos_cluster.c.

References dbscan_update_context(), destroy_strtree(), QueryContext::items_found, LW_FAILURE, LW_SUCCESS, LW_TRUE, lwalloc(), lwfree(), lwgeom_is_empty(), lwgeom_mindistance2d_tolerance(), make_strtree(), QueryContext::num_items_found, STRTree::tree, UF_find(), and UF_union().

Referenced by union_dbscan().

{
        uint32_t p, i;
        struct STRTree tree;
        struct QueryContext cxt =
        {
                .items_found = NULL,
                .num_items_found = 0,
                .items_found_size = 0
        };
        int success = LW_SUCCESS;

        if (in_a_cluster_ret)
        {
                char* in_a_cluster = lwalloc(num_geoms * sizeof(char));
                for (i = 0; i < num_geoms; i++)
                        in_a_cluster[i] = LW_TRUE;
                *in_a_cluster_ret = in_a_cluster;
        }

        if (num_geoms <= 1)
                return LW_SUCCESS;

        tree = make_strtree((void**) geoms, num_geoms, LW_TRUE);
        if (tree.tree == NULL)
        {
                destroy_strtree(&tree);
                return LW_FAILURE;
        }

        for (p = 0; p < num_geoms; p++)
        {
                if (lwgeom_is_empty(geoms[p]))
                        continue;

                dbscan_update_context(tree.tree, &cxt, geoms, p, eps);
                for (i = 0; i < cxt.num_items_found; i++)
                {
                        uint32_t q = *((uint32_t*) cxt.items_found[i]);

                        if (UF_find(uf, p) != UF_find(uf, q))
                        {
                                double mindist = lwgeom_mindistance2d_tolerance(geoms[p], geoms[q], eps);
                                if (mindist == FLT_MAX)
                                {
                                        success = LW_FAILURE;
                                        break;
                                }

                                if (mindist <= eps)
                                        UF_union(uf, p, q);
                        }
                }
        }

        if (cxt.items_found)
                lwfree(cxt.items_found);

        destroy_strtree(&tree);

        return success;
}

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