PostGIS  2.5.0dev-r@@SVN_REVISION@@
Datum ST_CollectionExtract ( PG_FUNCTION_ARGS  )

Definition at line 2686 of file lwgeom_functions_basic.c.

References LWGEOM::flags, FLAGS_GET_M, FLAGS_GET_Z, geometry_serialize(), LINETYPE, lwcollection_as_lwgeom(), lwcollection_extract(), lwgeom_construct_empty(), lwgeom_free(), lwgeom_from_gserialized(), lwgeom_is_collection(), POINTTYPE, POLYGONTYPE, LWGEOM::srid, and LWGEOM::type.

2687 {
2688  GSERIALIZED *input = PG_GETARG_GSERIALIZED_P(0);
2689  GSERIALIZED *output;
2690  LWGEOM *lwgeom = lwgeom_from_gserialized(input);
2691  LWGEOM *lwcol = NULL;
2692  int type = PG_GETARG_INT32(1);
2693  int lwgeom_type = lwgeom->type;
2694 
2695  /* Ensure the right type was input */
2696  if ( ! ( type == POINTTYPE || type == LINETYPE || type == POLYGONTYPE ) )
2697  {
2698  lwgeom_free(lwgeom);
2699  elog(ERROR, "ST_CollectionExtract: only point, linestring and polygon may be extracted");
2700  PG_RETURN_NULL();
2701  }
2702 
2703  /* Mirror non-collections right back */
2704  if ( ! lwgeom_is_collection(lwgeom) )
2705  {
2706  /* Non-collections of the matching type go back */
2707  if(lwgeom_type == type)
2708  {
2709  lwgeom_free(lwgeom);
2710  PG_RETURN_POINTER(input);
2711  }
2712  /* Others go back as EMPTY */
2713  else
2714  {
2715  lwcol = lwgeom_construct_empty(type, lwgeom->srid, FLAGS_GET_Z(lwgeom->flags), FLAGS_GET_M(lwgeom->flags));
2716  }
2717  }
2718  else
2719  {
2720  lwcol = lwcollection_as_lwgeom(lwcollection_extract((LWCOLLECTION*)lwgeom, type));
2721  }
2722 
2723  output = geometry_serialize((LWGEOM*)lwcol);
2724  lwgeom_free(lwgeom);
2725  lwgeom_free(lwcol);
2726 
2727  PG_RETURN_POINTER(output);
2728 }
#define LINETYPE
Definition: liblwgeom.h:85
int lwgeom_is_collection(const LWGEOM *lwgeom)
Determine whether a LWGEOM can contain sub-geometries or not.
Definition: lwgeom.c:1078
LWCOLLECTION * lwcollection_extract(LWCOLLECTION *col, int type)
Takes a potentially heterogeneous collection and returns a homogeneous collection consisting only of ...
Definition: lwcollection.c:372
LWGEOM * lwgeom_from_gserialized(const GSERIALIZED *g)
Allocate a new LWGEOM from a GSERIALIZED.
#define POLYGONTYPE
Definition: liblwgeom.h:86
uint8_t flags
Definition: liblwgeom.h:396
void lwgeom_free(LWGEOM *geom)
Definition: lwgeom.c:1137
int32_t srid
Definition: liblwgeom.h:398
#define FLAGS_GET_Z(flags)
Macros for manipulating the 'flags' byte.
Definition: liblwgeom.h:139
LWGEOM * lwgeom_construct_empty(uint8_t type, int srid, char hasz, char hasm)
Definition: lwgeom.c:2078
GSERIALIZED * geometry_serialize(LWGEOM *lwgeom)
#define POINTTYPE
LWTYPE numbers, used internally by PostGIS.
Definition: liblwgeom.h:84
#define FLAGS_GET_M(flags)
Definition: liblwgeom.h:140
uint8_t type
Definition: liblwgeom.h:395
LWGEOM * lwcollection_as_lwgeom(const LWCOLLECTION *obj)
Definition: lwgeom.c:299

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