ST_SwapOrdinates()

Datum ST_SwapOrdinates

(

PG_FUNCTION_ARGS

)

Definition at line 2835 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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