ST_SwapOrdinates()

Datum ST_SwapOrdinates

(

PG_FUNCTION_ARGS

)

Definition at line 2850 of file lwgeom_functions_basic.c.

{
        GSERIALIZED *in;
        GSERIALIZED *out;
        LWGEOM *lwgeom;
        const char *ospec;
        LWORD o1, o2;
 
        ospec = PG_GETARG_CSTRING(1);
        if (strlen(ospec) != 2)
        {
                lwpgerror(
                    "Invalid ordinate specification. "
                    "Need two letters from the set (x,y,z,m). "
                    "Got '%s'",
                    ospec);
                PG_RETURN_NULL();
        }
        o1 = ordname2ordval(ospec[0]);
        o2 = ordname2ordval(ospec[1]);
 
        in = PG_GETARG_GSERIALIZED_P_COPY(0);
 
        /* Check presence of given ordinates */
        if ((o1 == LWORD_M || o2 == LWORD_M) && !gserialized_has_m(in))
        {
                lwpgerror("Geometry does not have an M ordinate");
                PG_RETURN_NULL();
        }
        if ((o1 == LWORD_Z || o2 == LWORD_Z) && !gserialized_has_z(in))
        {
                lwpgerror("Geometry does not have a Z ordinate");
                PG_RETURN_NULL();
        }
 
        /* Nothing to do if swapping the same ordinate, pity for the copy... */
        if (o1 == o2)
                PG_RETURN_POINTER(in);
 
        lwgeom = lwgeom_from_gserialized(in);
        lwgeom_swap_ordinates(lwgeom, o1, o2);
        out = geometry_serialize(lwgeom);
        lwgeom_free(lwgeom);
        PG_FREE_IF_COPY(in, 0);
        PG_RETURN_POINTER(out);
}

References geometry_serialize(), gserialized_has_m(), gserialized_has_z(), lwgeom_free(), lwgeom_from_gserialized(), lwgeom_swap_ordinates(), LWORD_M, LWORD_Z, and ordname2ordval().

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