LWGEOM_collect()

Datum LWGEOM_collect

(

PG_FUNCTION_ARGS

)

Definition at line 1131 of file lwgeom_functions_basic.c.

{
        GSERIALIZED *gser1, *gser2, *result;
        LWGEOM *lwgeoms[2], *outlwg;
    uint32 type1, type2;
    uint8_t outtype;
        int srid;
 
        POSTGIS_DEBUG(2, "LWGEOM_collect called.");
 
        /* return null if both geoms are null */
        if ( PG_ARGISNULL(0) && PG_ARGISNULL(1) )
                PG_RETURN_NULL();
 
        /* Return the second geom if the first geom is null */
        if (PG_ARGISNULL(0))
                PG_RETURN_DATUM(PG_GETARG_DATUM(1));
 
        /* Return the first geom if the second geom is null */
        if (PG_ARGISNULL(1))
                PG_RETURN_DATUM(PG_GETARG_DATUM(0));
 
        gser1 = PG_GETARG_GSERIALIZED_P(0);
        gser2 = PG_GETARG_GSERIALIZED_P(1);
 
        POSTGIS_DEBUGF(3, "LWGEOM_collect(%s, %s): call", lwtype_name(gserialized_get_type(gser1)), lwtype_name(gserialized_get_type(gser2)));
 
        if ( FLAGS_GET_ZM(gser1->flags) != FLAGS_GET_ZM(gser2->flags) )
        {
                elog(ERROR,"Cannot ST_Collect geometries with differing dimensionality.");
                PG_RETURN_NULL();
        }
 
        srid = gserialized_get_srid(gser1);
        error_if_srid_mismatch(srid, gserialized_get_srid(gser2));
 
        lwgeoms[0] = lwgeom_from_gserialized(gser1);
        lwgeoms[1] = lwgeom_from_gserialized(gser2);
 
        type1 = lwgeoms[0]->type;
        type2 = lwgeoms[1]->type;
 
        if ( (type1 == type2) && (!lwgeom_is_collection(lwgeoms[0])) )
                outtype = lwtype_get_collectiontype(type1);
        else
                outtype = COLLECTIONTYPE;
 
        POSTGIS_DEBUGF(3, " outtype = %d", outtype);
 
        /* Drop input geometries bbox and SRID */
        lwgeom_drop_bbox(lwgeoms[0]);
        lwgeom_drop_srid(lwgeoms[0]);
        lwgeom_drop_bbox(lwgeoms[1]);
        lwgeom_drop_srid(lwgeoms[1]);
 
        outlwg = (LWGEOM *)lwcollection_construct(outtype, srid, NULL, 2, lwgeoms);
        result = geometry_serialize(outlwg);
 
        lwgeom_free(lwgeoms[0]);
        lwgeom_free(lwgeoms[1]);
 
        PG_FREE_IF_COPY(gser1, 0);
        PG_FREE_IF_COPY(gser2, 1);
 
        PG_RETURN_POINTER(result);
}

References COLLECTIONTYPE, error_if_srid_mismatch(), GSERIALIZED::flags, FLAGS_GET_ZM, geometry_serialize(), gserialized_get_srid(), gserialized_get_type(), lwcollection_construct(), lwgeom_drop_bbox(), lwgeom_drop_srid(), lwgeom_free(), lwgeom_from_gserialized(), lwgeom_is_collection(), lwtype_get_collectiontype(), lwtype_name(), and LWGEOM::type.

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