isring()

Datum isring

(

PG_FUNCTION_ARGS

)

Definition at line 2785 of file postgis/lwgeom_geos.c.

{
        GSERIALIZED *geom;
        GEOSGeometry *g1;
        int result;
 
        geom = PG_GETARG_GSERIALIZED_P(0);
 
        /* Empty things can't close */
        if ( gserialized_is_empty(geom) )
                PG_RETURN_BOOL(false);
 
        initGEOS(lwpgnotice, lwgeom_geos_error);
 
        g1 = POSTGIS2GEOS(geom);
        if (!g1)
                HANDLE_GEOS_ERROR("First argument geometry could not be converted to GEOS");
 
        if ( GEOSGeomTypeId(g1) != GEOS_LINESTRING )
        {
                GEOSGeom_destroy(g1);
                elog(ERROR, "ST_IsRing() should only be called on a linear feature");
        }
 
        result = GEOSisRing(g1);
        GEOSGeom_destroy(g1);
 
        if (result == 2) HANDLE_GEOS_ERROR("GEOSisRing");
 
        PG_FREE_IF_COPY(geom, 0);
        PG_RETURN_BOOL(result);
}

References gserialized_is_empty(), HANDLE_GEOS_ERROR, lwgeom_geos_error(), POSTGIS2GEOS(), and result.

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