TWKBFromLWGEOMArray()

Datum TWKBFromLWGEOMArray

(

PG_FUNCTION_ARGS

)

Definition at line 522 of file lwgeom_inout.c.

{
        ArrayType *arr_geoms = NULL;
        ArrayType *arr_ids = NULL;
        int num_geoms, num_ids, i = 0;
 
        ArrayIterator iter_geoms, iter_ids;
        bool null_geom, null_id;
        Datum val_geom, val_id;
 
        int is_homogeneous = true;
        uint32_t subtype = 0;
        int has_z = 0;
        int has_m  = 0;
        LWCOLLECTION *col = NULL;
        int64_t *idlist = NULL;
        uint8_t variant = 0;
 
        srs_precision sp;
        uint8_t *twkb;
        size_t twkb_size;
        bytea *result;
 
        /* The first two arguments are required */
        if ( PG_NARGS() < 2 || PG_ARGISNULL(0) || PG_ARGISNULL(1) )
                PG_RETURN_NULL();
 
        arr_geoms = PG_GETARG_ARRAYTYPE_P(0);
        arr_ids = PG_GETARG_ARRAYTYPE_P(1);
 
        num_geoms = ArrayGetNItems(ARR_NDIM(arr_geoms), ARR_DIMS(arr_geoms));
        num_ids = ArrayGetNItems(ARR_NDIM(arr_ids), ARR_DIMS(arr_ids));
 
        if ( num_geoms != num_ids )
        {
                elog(ERROR, "size of geometry[] and integer[] arrays must match");
                PG_RETURN_NULL();
        }
 
        /* Loop through array and build a collection of geometry and */
        /* a simple array of ids. If either side is NULL, skip it */
 
#if POSTGIS_PGSQL_VERSION >= 95
        iter_geoms = array_create_iterator(arr_geoms, 0, NULL);
        iter_ids = array_create_iterator(arr_ids, 0, NULL);
#else
        iter_geoms = array_create_iterator(arr_geoms, 0);
        iter_ids = array_create_iterator(arr_ids, 0);
#endif
 
        while( array_iterate(iter_geoms, &val_geom, &null_geom) &&
               array_iterate(iter_ids, &val_id, &null_id) )
        {
                LWGEOM *geom;
                int32_t uid;
 
                if ( null_geom || null_id )
                {
                        elog(NOTICE, "ST_AsTWKB skipping NULL entry at position %d", i);
                        continue;
                }
 
                geom = lwgeom_from_gserialized((GSERIALIZED*)DatumGetPointer(val_geom));
                uid = DatumGetInt64(val_id);
 
                /* Construct collection/idlist first time through */
                if ( ! col )
                {
                        has_z = lwgeom_has_z(geom);
                        has_m = lwgeom_has_m(geom);
                        col = lwcollection_construct_empty(COLLECTIONTYPE, lwgeom_get_srid(geom), has_z, has_m);
                }
                if ( ! idlist )
                        idlist = palloc0(num_geoms * sizeof(int64_t));
 
 
                /* Check if there is differences in dimensionality*/
                if( lwgeom_has_z(geom)!=has_z || lwgeom_has_m(geom)!=has_m)
                {
                        elog(ERROR, "Geometries have different dimensionality");
                        PG_FREE_IF_COPY(arr_geoms, 0);
                        PG_FREE_IF_COPY(arr_ids, 1);
                        PG_RETURN_NULL();
                }
                /* Store the values */
                lwcollection_add_lwgeom(col, geom);
                idlist[i++] = uid;
 
                /* Grab the geometry type and note if all geometries share it */
                /* If so, we can make this a homogeneous collection and save some space */
                if ( lwgeom_get_type(geom) != subtype && subtype )
                {
                        is_homogeneous = false;
                }
                else
                {
                        subtype = lwgeom_get_type(geom);
                }
 
        }
        array_free_iterator(iter_geoms);
        array_free_iterator(iter_ids);
 
        if(i==0)
        {
                elog(NOTICE, "No valid geometry - id pairs found");
                PG_FREE_IF_COPY(arr_geoms, 0);
                PG_FREE_IF_COPY(arr_ids, 1);
                PG_RETURN_NULL();
        }
        if ( is_homogeneous )
        {
                col->type = lwtype_get_collectiontype(subtype);
        }
 
        /* Read sensible precision defaults (about one meter) given the srs */
        sp = srid_axis_precision(fcinfo, lwgeom_get_srid(lwcollection_as_lwgeom(col)), TWKB_DEFAULT_PRECISION);
 
        /* If user specified XY precision, use it */
        if ( PG_NARGS() > 2 && ! PG_ARGISNULL(2) )
                sp.precision_xy = PG_GETARG_INT32(2);
 
        /* If user specified Z precision, use it */
        if ( PG_NARGS() > 3 && ! PG_ARGISNULL(3) )
                sp.precision_z = PG_GETARG_INT32(3);
 
        /* If user specified M precision, use it */
        if ( PG_NARGS() > 4 && ! PG_ARGISNULL(4) )
                sp.precision_m = PG_GETARG_INT32(4);
 
        /* We are building an ID'ed output */
        variant = TWKB_ID;
 
        /* If user wants registered twkb sizes */
        if ( PG_NARGS() > 5 && ! PG_ARGISNULL(5) && PG_GETARG_BOOL(5) )
                variant |= TWKB_SIZE;
 
        /* If user wants bounding boxes */
        if ( PG_NARGS() > 6 && ! PG_ARGISNULL(6) && PG_GETARG_BOOL(6) )
                variant |= TWKB_BBOX;
 
        /* Write out the TWKB */
        twkb = lwgeom_to_twkb_with_idlist(lwcollection_as_lwgeom(col),
                                          idlist, variant,
                                          sp.precision_xy, sp.precision_z, sp.precision_m,
                                          &twkb_size);
 
        /* Convert to a bytea return type */
        result = palloc(twkb_size + VARHDRSZ);
        memcpy(VARDATA(result), twkb, twkb_size);
        SET_VARSIZE(result, twkb_size + VARHDRSZ);
 
        /* Clean up */
        pfree(twkb);
        pfree(idlist);
        lwcollection_free(col);
        PG_FREE_IF_COPY(arr_geoms, 0);
        PG_FREE_IF_COPY(arr_ids, 1);
 
        PG_RETURN_BYTEA_P(result);
}

References COLLECTIONTYPE, lwcollection_add_lwgeom(), lwcollection_as_lwgeom(), lwcollection_construct_empty(), lwcollection_free(), lwgeom_from_gserialized(), lwgeom_get_srid(), lwgeom_get_type(), lwgeom_has_m(), lwgeom_has_z(), lwgeom_to_twkb_with_idlist(), lwtype_get_collectiontype(), TWKB_BBOX, TWKB_DEFAULT_PRECISION, TWKB_ID, TWKB_SIZE, LWCOLLECTION::type, and variant.

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