isring()

Datum isring

(

PG_FUNCTION_ARGS

)

Definition at line 2880 of file postgis/lwgeom_geos.c.

References FALSE, dumpnode::geom, gserialized_is_empty(), HANDLE_GEOS_ERROR, lwgeom_geos_error(), and POSTGIS2GEOS().

Referenced by issimple().

{
        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 = (GEOSGeometry *)POSTGIS2GEOS(geom);
        if ( 0 == g1 )   /* exception thrown at construction */
        {
                HANDLE_GEOS_ERROR("First argument geometry could not be converted to GEOS");
                PG_RETURN_NULL();
        }

        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_RETURN_NULL();
        }

        PG_FREE_IF_COPY(geom, 0);
        PG_RETURN_BOOL(result);
}

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