cluster_within_distance_garray()

Datum cluster_within_distance_garray

(

PG_FUNCTION_ARGS

)

Definition at line 3256 of file postgis/lwgeom_geos.c.

References ARRAY2LWGEOM(), array_nelems_not_null(), cluster_within_distance(), gserialized_from_lwgeom(), linemerge(), LW_SUCCESS, lwgeom_free(), lwgeom_geos_error(), PG_FUNCTION_INFO_V1(), and SRID_UNKNOWN.

Referenced by clusterintersecting_garray(), and pgis_geometry_clusterwithin_finalfn().

{
        Datum* result_array_data;
        ArrayType *array, *result;
        int is3d = 0;
        uint32 nelems, nclusters, i;
        LWGEOM** lw_inputs;
        LWGEOM** lw_results;
        double tolerance;
        int srid=SRID_UNKNOWN;

        /* Parameters used to construct a result array */
        int16 elmlen;
        bool elmbyval;
        char elmalign;

        /* Null array, null geometry (should be empty?) */
        if (PG_ARGISNULL(0))
                PG_RETURN_NULL();

        array = PG_GETARG_ARRAYTYPE_P(0);

        tolerance = PG_GETARG_FLOAT8(1);
        if (tolerance < 0)
        {
                lwpgerror("Tolerance must be a positive number.");
                PG_RETURN_NULL();
        }

        nelems = array_nelems_not_null(array);

        POSTGIS_DEBUGF(3, "cluster_within_distance_garray: number of non-null elements: %d", nelems);

        if ( nelems == 0 ) PG_RETURN_NULL();

    /* TODO short-circuit for one element? */

        /* Ok, we really need geos now ;) */
        initGEOS(lwpgnotice, lwgeom_geos_error);

        lw_inputs = ARRAY2LWGEOM(array, nelems, &is3d, &srid);
        if (!lw_inputs)
        {
                PG_RETURN_NULL();
        }

        if (cluster_within_distance(lw_inputs, nelems, tolerance, &lw_results, &nclusters) != LW_SUCCESS)
        {
                elog(ERROR, "cluster_within: Error performing clustering");
                PG_RETURN_NULL();
        }
        pfree(lw_inputs); /* don't need to destroy items because GeometryCollections have taken ownership */

        if (!lw_results) PG_RETURN_NULL();

        result_array_data = palloc(nclusters * sizeof(Datum));
        for (i=0; i<nclusters; ++i)
        {
                result_array_data[i] = PointerGetDatum(gserialized_from_lwgeom(lw_results[i], NULL));
                lwgeom_free(lw_results[i]);
        }
        pfree(lw_results);

        get_typlenbyvalalign(array->elemtype, &elmlen, &elmbyval, &elmalign);
        result = (ArrayType*) construct_array(result_array_data, nclusters, array->elemtype, elmlen, elmbyval, elmalign);

        if (!result)
        {
                elog(ERROR, "clusterwithin: Error constructing return-array");
                PG_RETURN_NULL();
        }

        PG_RETURN_POINTER(result);
}

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