LWGEOM_geometryn_collection()

Datum LWGEOM_geometryn_collection

(

PG_FUNCTION_ARGS

)

Definition at line 260 of file lwgeom_ogc.c.

{
        GSERIALIZED *geom = PG_GETARG_GSERIALIZED_P(0);
        GSERIALIZED *result;
        int type = gserialized_get_type(geom);
        int32 idx;
        LWCOLLECTION *coll;
        LWGEOM *subgeom;
 
        POSTGIS_DEBUG(2, "LWGEOM_geometryn_collection called.");
 
        /* elog(NOTICE, "GeometryN called"); */
 
        idx = PG_GETARG_INT32(1);
        idx -= 1; /* index is 1-based */
 
        if (gserialized_is_empty(geom))
        {
                PG_RETURN_NULL();
        }
 
        /* call is valid on multi* geoms only */
        if (type==POINTTYPE     || type==LINETYPE    || type==CIRCSTRINGTYPE ||
            type==COMPOUNDTYPE  || type==POLYGONTYPE ||
            type==CURVEPOLYTYPE || type==TRIANGLETYPE)
        {
                if ( idx == 0 ) PG_RETURN_POINTER(geom);
                PG_RETURN_NULL();
        }
 
        coll = lwgeom_as_lwcollection(lwgeom_from_gserialized(geom));
 
        if ( idx < 0 ) PG_RETURN_NULL();
        if ( idx >= (int32) coll->ngeoms ) PG_RETURN_NULL();
 
        subgeom = coll->geoms[idx];
        subgeom->srid = coll->srid;
 
        /* COMPUTE_BBOX==TAINTING */
        if ( coll->bbox ) lwgeom_add_bbox(subgeom);
 
        result = geometry_serialize(subgeom);
 
        lwcollection_free(coll);
        PG_FREE_IF_COPY(geom, 0);
 
        PG_RETURN_POINTER(result);
 
}

References LWCOLLECTION::bbox, CIRCSTRINGTYPE, COMPOUNDTYPE, CURVEPOLYTYPE, LWCOLLECTION::geoms, gserialized_get_type(), gserialized_is_empty(), LINETYPE, lwcollection_free(), lwgeom_add_bbox(), lwgeom_as_lwcollection(), lwgeom_from_gserialized(), LWCOLLECTION::ngeoms, POINTTYPE, POLYGONTYPE, result, LWGEOM::srid, LWCOLLECTION::srid, TRIANGLETYPE, and ovdump::type.

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