PostGIS  2.2.8dev-r@@SVN_REVISION@@

◆ lwgeom_symdifference()

LWGEOM* lwgeom_symdifference ( const LWGEOM geom1,
const LWGEOM geom2 
)

Definition at line 815 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().

816 {
817  GEOSGeometry *g1, *g2, *g3;
818  LWGEOM *result;
819  int is3d;
820  int srid;
821 
822  /* A.SymDifference(Empty) == A */
823  if ( lwgeom_is_empty(geom2) )
824  return lwgeom_clone_deep(geom1);
825 
826  /* Empty.DymDifference(B) == B */
827  if ( lwgeom_is_empty(geom1) )
828  return lwgeom_clone_deep(geom2);
829 
830  /* ensure srids are identical */
831  srid = (int)(geom1->srid);
832  error_if_srid_mismatch(srid, (int)(geom2->srid));
833 
834  is3d = (FLAGS_GET_Z(geom1->flags) || FLAGS_GET_Z(geom2->flags)) ;
835 
836  initGEOS(lwnotice, lwgeom_geos_error);
837 
838  g1 = LWGEOM2GEOS(geom1, 0);
839 
840  if ( 0 == g1 ) /* exception thrown at construction */
841  {
842  lwerror("First argument geometry could not be converted to GEOS: %s", lwgeom_geos_errmsg);
843  return NULL;
844  }
845 
846  g2 = LWGEOM2GEOS(geom2, 0);
847 
848  if ( 0 == g2 ) /* exception thrown at construction */
849  {
850  lwerror("Second argument geometry could not be converted to GEOS: %s", lwgeom_geos_errmsg);
851  GEOSGeom_destroy(g1);
852  return NULL;
853  }
854 
855  g3 = GEOSSymDifference(g1,g2);
856 
857  if (g3 == NULL)
858  {
859  GEOSGeom_destroy(g1);
860  GEOSGeom_destroy(g2);
861  lwerror("GEOSSymDifference: %s", lwgeom_geos_errmsg);
862  return NULL; /*never get here */
863  }
864 
865  LWDEBUGF(3, "result: %s", GEOSGeomToWKT(g3));
866 
867  GEOSSetSRID(g3, srid);
868 
869  result = GEOS2LWGEOM(g3, is3d);
870 
871  if (result == NULL)
872  {
873  GEOSGeom_destroy(g1);
874  GEOSGeom_destroy(g2);
875  GEOSGeom_destroy(g3);
876  lwerror("GEOS symdifference() threw an error (result postgis geometry formation)!");
877  return NULL ; /*never get here */
878  }
879 
880  GEOSGeom_destroy(g1);
881  GEOSGeom_destroy(g2);
882  GEOSGeom_destroy(g3);
883 
884  return result;
885 }
void lwnotice(const char *fmt,...)
Write a notice out to the notice handler.
Definition: lwutil.c:61
uint8_t flags
Definition: liblwgeom.h:381
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:433
void error_if_srid_mismatch(int srid1, int srid2)
Definition: lwutil.c:341
int32_t srid
Definition: liblwgeom.h:383
void lwgeom_geos_error(const char *fmt,...)
#define FLAGS_GET_Z(flags)
Macros for manipulating the 'flags' byte.
Definition: liblwgeom.h:124
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:1297
#define LWDEBUGF(level, msg,...)
Definition: lwgeom_log.h:55
void lwerror(const char *fmt,...)
Write a notice out to the error handler.
Definition: lwutil.c:74
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