PostGIS  3.1.6dev-r@@SVN_REVISION@@

◆ pgis_union_geometry_array()

Datum pgis_union_geometry_array ( PG_FUNCTION_ARGS  )

Definition at line 474 of file postgis/lwgeom_geos.c.

475 {
476  ArrayType *array;
477 
478  ArrayIterator iterator;
479  Datum value;
480  bool isnull;
481 
482  int is3d = LW_FALSE, gotsrid = LW_FALSE;
483  int nelems = 0, geoms_size = 0, curgeom = 0, count = 0;
484 
485  GSERIALIZED *gser_out = NULL;
486 
487  GEOSGeometry *g = NULL;
488  GEOSGeometry *g_union = NULL;
489  GEOSGeometry **geoms = NULL;
490 
491  int32_t srid = SRID_UNKNOWN;
492 
493  int empty_type = 0;
494 
495  /* Null array, null geometry (should be empty?) */
496  if ( PG_ARGISNULL(0) )
497  PG_RETURN_NULL();
498 
499  array = PG_GETARG_ARRAYTYPE_P(0);
500  nelems = ArrayGetNItems(ARR_NDIM(array), ARR_DIMS(array));
501 
502  /* Empty array? Null return */
503  if ( nelems == 0 ) PG_RETURN_NULL();
504 
505  /* Quick scan for nulls */
506  iterator = array_create_iterator(array, 0, NULL);
507  while (array_iterate(iterator, &value, &isnull))
508  {
509  /* Skip null array items */
510  if (isnull) continue;
511  count++;
512  }
513  array_free_iterator(iterator);
514 
515 
516  /* All-nulls? Return null */
517  if ( count == 0 )
518  PG_RETURN_NULL();
519 
520  /* One geom, good geom? Return it */
521  if ( count == 1 && nelems == 1 )
522  {
523 #if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 6)
524 #pragma GCC diagnostic push
525 #pragma GCC diagnostic ignored "-Wsign-compare"
526 #endif
527  PG_RETURN_POINTER((GSERIALIZED *)(ARR_DATA_PTR(array)));
528 #if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 6)
529 #pragma GCC diagnostic pop
530 #endif
531  }
532 
533  /* Ok, we really need GEOS now ;) */
534  initGEOS(lwpgnotice, lwgeom_geos_error);
535 
536  /*
537  ** Collect the non-empty inputs and stuff them into a GEOS collection
538  */
539  geoms_size = nelems;
540  geoms = palloc(sizeof(GEOSGeometry*) * geoms_size);
541 
542  /*
543  ** We need to convert the array of GSERIALIZED into a GEOS collection.
544  ** First make an array of GEOS geometries.
545  */
546  iterator = array_create_iterator(array, 0, NULL);
547  while (array_iterate(iterator, &value, &isnull))
548  {
549  GSERIALIZED *gser_in;
550 
551  /* Skip null array items */
552  if (isnull) continue;
553  gser_in = (GSERIALIZED *)DatumGetPointer(value);
554 
555  /* Check for SRID mismatch in array elements */
556  if ( gotsrid )
557  gserialized_error_if_srid_mismatch_reference(gser_in, srid, __func__);
558  else
559  {
560  /* Initialize SRID/dimensions info */
561  srid = gserialized_get_srid(gser_in);
562  is3d = gserialized_has_z(gser_in);
563  gotsrid = 1;
564  }
565 
566  /* Don't include empties in the union */
567  if ( gserialized_is_empty(gser_in) )
568  {
569  int gser_type = gserialized_get_type(gser_in);
570  if (gser_type > empty_type)
571  {
572  empty_type = gser_type;
573  POSTGIS_DEBUGF(4, "empty_type = %d gser_type = %d", empty_type, gser_type);
574  }
575  }
576  else
577  {
578  g = POSTGIS2GEOS(gser_in);
579 
580  /* Uh oh! Exception thrown at construction... */
581  if ( ! g )
582  {
584  "One of the geometries in the set "
585  "could not be converted to GEOS");
586  }
587 
588  /* Ensure we have enough space in our storage array */
589  if ( curgeom == geoms_size )
590  {
591  geoms_size *= 2;
592  geoms = repalloc( geoms, sizeof(GEOSGeometry*) * geoms_size );
593  }
594 
595  geoms[curgeom] = g;
596  curgeom++;
597  }
598 
599  }
600  array_free_iterator(iterator);
601 
602  /*
603  ** Take our GEOS geometries and turn them into a GEOS collection,
604  ** then pass that into cascaded union.
605  */
606  if (curgeom > 0)
607  {
608  g = GEOSGeom_createCollection(GEOS_GEOMETRYCOLLECTION, geoms, curgeom);
609  if (!g) HANDLE_GEOS_ERROR("Could not create GEOS COLLECTION from geometry array");
610 
611  g_union = GEOSUnaryUnion(g);
612  GEOSGeom_destroy(g);
613  if (!g_union) HANDLE_GEOS_ERROR("GEOSUnaryUnion");
614 
615  GEOSSetSRID(g_union, srid);
616  gser_out = GEOS2POSTGIS(g_union, is3d);
617  GEOSGeom_destroy(g_union);
618  }
619  /* No real geometries in our array, any empties? */
620  else
621  {
622  /* If it was only empties, we'll return the largest type number */
623  if ( empty_type > 0 )
624  {
625  PG_RETURN_POINTER(geometry_serialize(lwgeom_construct_empty(empty_type, srid, is3d, 0)));
626  }
627  /* Nothing but NULL, returns NULL */
628  else
629  {
630  PG_RETURN_NULL();
631  }
632  }
633 
634  if ( ! gser_out )
635  {
636  /* Union returned a NULL geometry */
637  PG_RETURN_NULL();
638  }
639 
640  PG_RETURN_POINTER(gser_out);
641 }
void gserialized_error_if_srid_mismatch_reference(const GSERIALIZED *g1, const int32_t srid2, const char *funcname)
Definition: gserialized.c:419
int32_t gserialized_get_srid(const GSERIALIZED *g)
Extract the SRID from the serialized form (it is packed into three bytes so this is a handy function)...
Definition: gserialized.c:126
int gserialized_is_empty(const GSERIALIZED *g)
Check if a GSERIALIZED is empty without deserializing first.
Definition: gserialized.c:152
int gserialized_has_z(const GSERIALIZED *g)
Check if a GSERIALIZED has a Z ordinate.
Definition: gserialized.c:174
uint32_t gserialized_get_type(const GSERIALIZED *g)
Extract the geometry type from the serialized form (it hides in the anonymous data area,...
Definition: gserialized.c:89
void lwgeom_geos_error(const char *fmt,...)
#define LW_FALSE
Definition: liblwgeom.h:108
#define SRID_UNKNOWN
Unknown SRID value.
Definition: liblwgeom.h:229
LWGEOM * lwgeom_construct_empty(uint8_t type, int32_t srid, char hasz, char hasm)
Definition: lwgeom.c:2082
int value
Definition: genraster.py:62
int count
Definition: genraster.py:57
#define HANDLE_GEOS_ERROR(label)
GSERIALIZED * GEOS2POSTGIS(GEOSGeom geom, char want3d)
GEOSGeometry * POSTGIS2GEOS(const GSERIALIZED *pglwgeom)

References genraster::count, GEOS2POSTGIS(), gserialized_error_if_srid_mismatch_reference(), gserialized_get_srid(), gserialized_get_type(), gserialized_has_z(), gserialized_is_empty(), HANDLE_GEOS_ERROR, LW_FALSE, lwgeom_construct_empty(), lwgeom_geos_error(), POSTGIS2GEOS(), SRID_UNKNOWN, and genraster::value.

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