PostGIS  2.5.1dev-r@@SVN_REVISION@@

◆ lwgeom_difference()

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

Definition at line 693 of file liblwgeom/lwgeom_geos.c.

References AUTOFIX, LWGEOM::flags, FLAGS_GET_Z, GEOS2LWGEOM(), GEOS_FAIL, GEOS_FREE, GEOS_FREE_AND_FAIL, LWGEOM2GEOS(), lwgeom_clone_deep(), lwgeom_geos_error(), lwgeom_is_empty(), lwnotice(), RESULT_SRID, and SRID_INVALID.

Referenced by _lwt_AddLine(), and geos_difference().

694 {
695  LWGEOM* result;
696  int32_t srid = RESULT_SRID(geom1, geom2);
697  uint8_t is3d = (FLAGS_GET_Z(geom1->flags) || FLAGS_GET_Z(geom2->flags));
698  GEOSGeometry *g1, *g2, *g3;
699 
700  if (srid == SRID_INVALID) return NULL;
701 
702  /* A.Intersection(Empty) == Empty */
703  if (lwgeom_is_empty(geom2)) return lwgeom_clone_deep(geom1); /* match empty type? */
704 
705  /* Empty.Intersection(A) == Empty */
706  if (lwgeom_is_empty(geom1)) return lwgeom_clone_deep(geom1); /* match empty type? */
707 
708  initGEOS(lwnotice, lwgeom_geos_error);
709 
710  if (!(g1 = LWGEOM2GEOS(geom1, AUTOFIX))) GEOS_FAIL();
711  if (!(g2 = LWGEOM2GEOS(geom2, AUTOFIX))) GEOS_FREE_AND_FAIL(g1);
712 
713  g3 = GEOSDifference(g1, g2);
714 
715  if (!g3) GEOS_FREE_AND_FAIL(g1, g2);
716  GEOSSetSRID(g3, srid);
717 
718  if (!(result = GEOS2LWGEOM(g3, is3d)))
719  GEOS_FREE_AND_FAIL(g1, g2, g3);
720 
721  GEOS_FREE(g1, g2, g3);
722  return result;
723 }
#define GEOS_FAIL()
LWGEOM * GEOS2LWGEOM(const GEOSGeometry *geom, uint8_t want3d)
void lwnotice(const char *fmt,...)
Write a notice out to the notice handler.
Definition: lwutil.c:177
uint8_t flags
Definition: liblwgeom.h:399
#define GEOS_FREE_AND_FAIL(...)
#define GEOS_FREE(...)
LWGEOM * lwgeom_clone_deep(const LWGEOM *lwgeom)
Deep clone an LWGEOM, everything is copied.
Definition: lwgeom.c:520
#define RESULT_SRID(...)
#define AUTOFIX
void lwgeom_geos_error(const char *fmt,...)
#define SRID_INVALID
Definition: liblwgeom.h:191
#define FLAGS_GET_Z(flags)
Macros for manipulating the 'flags' byte.
Definition: liblwgeom.h:139
GEOSGeometry * LWGEOM2GEOS(const LWGEOM *lwgeom, uint8_t autofix)
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:1393
unsigned char uint8_t
Definition: uthash.h:79
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