PostGIS  2.3.7dev-r@@SVN_REVISION@@
LWGEOM* lwgeom_symdifference ( const LWGEOM geom1,
const LWGEOM geom2 
)

Definition at line 841 of file liblwgeom/lwgeom_geos.c.

References error_if_srid_mismatch(), LWGEOM::flags, FLAGS_GET_Z, GEOS2LWGEOM(), LWDEBUGF, lwerror(), LWGEOM2GEOS(), lwgeom_clone_deep(), lwgeom_geos_errmsg, lwgeom_geos_error(), lwgeom_is_empty(), lwnotice(), and LWGEOM::srid.

Referenced by symdifference().

842 {
843  GEOSGeometry *g1, *g2, *g3;
844  LWGEOM *result;
845  int is3d;
846  int srid;
847 
848  /* A.SymDifference(Empty) == A */
849  if ( lwgeom_is_empty(geom2) )
850  return lwgeom_clone_deep(geom1);
851 
852  /* Empty.DymDifference(B) == B */
853  if ( lwgeom_is_empty(geom1) )
854  return lwgeom_clone_deep(geom2);
855 
856  /* ensure srids are identical */
857  srid = (int)(geom1->srid);
858  error_if_srid_mismatch(srid, (int)(geom2->srid));
859 
860  is3d = (FLAGS_GET_Z(geom1->flags) || FLAGS_GET_Z(geom2->flags)) ;
861 
862  initGEOS(lwnotice, lwgeom_geos_error);
863 
864  g1 = LWGEOM2GEOS(geom1, 0);
865 
866  if ( 0 == g1 ) /* exception thrown at construction */
867  {
868  lwerror("First argument geometry could not be converted to GEOS: %s", lwgeom_geos_errmsg);
869  return NULL;
870  }
871 
872  g2 = LWGEOM2GEOS(geom2, 0);
873 
874  if ( 0 == g2 ) /* exception thrown at construction */
875  {
876  lwerror("Second argument geometry could not be converted to GEOS: %s", lwgeom_geos_errmsg);
877  GEOSGeom_destroy(g1);
878  return NULL;
879  }
880 
881  g3 = GEOSSymDifference(g1,g2);
882 
883  if (g3 == NULL)
884  {
885  GEOSGeom_destroy(g1);
886  GEOSGeom_destroy(g2);
887  lwerror("GEOSSymDifference: %s", lwgeom_geos_errmsg);
888  return NULL; /*never get here */
889  }
890 
891  LWDEBUGF(3, "result: %s", GEOSGeomToWKT(g3));
892 
893  GEOSSetSRID(g3, srid);
894 
895  result = GEOS2LWGEOM(g3, is3d);
896 
897  if (result == NULL)
898  {
899  GEOSGeom_destroy(g1);
900  GEOSGeom_destroy(g2);
901  GEOSGeom_destroy(g3);
902  lwerror("GEOS symdifference() threw an error (result postgis geometry formation)!");
903  return NULL ; /*never get here */
904  }
905 
906  GEOSGeom_destroy(g1);
907  GEOSGeom_destroy(g2);
908  GEOSGeom_destroy(g3);
909 
910  return result;
911 }
void lwnotice(const char *fmt,...)
Write a notice out to the notice handler.
Definition: lwutil.c:89
uint8_t flags
Definition: liblwgeom.h:396
char lwgeom_geos_errmsg[LWGEOM_GEOS_ERRMSG_MAXSIZE]
LWGEOM * lwgeom_clone_deep(const LWGEOM *lwgeom)
Deep clone an LWGEOM, everything is copied.
Definition: lwgeom.c:446
void error_if_srid_mismatch(int srid1, int srid2)
Definition: lwutil.c:369
int32_t srid
Definition: liblwgeom.h:398
void lwgeom_geos_error(const char *fmt,...)
#define FLAGS_GET_Z(flags)
Macros for manipulating the 'flags' byte.
Definition: liblwgeom.h:139
GEOSGeometry * LWGEOM2GEOS(const LWGEOM *lwgeom, int autofix)
LWGEOM * GEOS2LWGEOM(const GEOSGeometry *geom, char want3d)
int lwgeom_is_empty(const LWGEOM *geom)
Return true or false depending on whether a geometry is an "empty" geometry (no vertices members) ...
Definition: lwgeom.c:1310
#define LWDEBUGF(level, msg,...)
Definition: lwgeom_log.h:88
void lwerror(const char *fmt,...)
Write a notice out to the error handler.
Definition: lwutil.c:102

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