Added collect_garray() function.

git-svn-id: http://svn.osgeo.org/postgis/trunk@337 b70326c6-7e19-0410-871a-916f4a2858ee

diff --git a/postgis.h b/postgis.h
index 4e3e06a6038ed38584c5fae17bbdd3ab58244bf8..a3e2feb097933458fbdce51363459d49a058c70a 100644 (file)
--- a/postgis.h
+++ b/postgis.h
@@ -11,6 +11,9 @@
  *
  **********************************************************************
  * $Log$
+ * Revision 1.37  2003/10/28 16:57:35  strk
+ * Added collect_garray() function.
+ *
  * Revision 1.36  2003/10/28 15:16:17  strk
  * unite_sfunc() from postgis_geos.c renamed to geom_accum() and moved in postgis_fn.c
  *
@@ -580,6 +583,7 @@ Datum transform_geom(PG_FUNCTION_ARGS);
 
 Datum max_distance(PG_FUNCTION_ARGS);
 Datum geom_accum(PG_FUNCTION_ARGS);
+Datum collect_garray(PG_FUNCTION_ARGS);
 Datum collector(PG_FUNCTION_ARGS);
 
 Datum WKBtoBYTEA(PG_FUNCTION_ARGS);

diff --git a/postgis_fn.c b/postgis_fn.c
index 758010f183c65273835ead65903a3477f6c93f57..a0de8a6abfaf34c48cf6532c077e258acd5c1e88 100644 (file)
--- a/postgis_fn.c
+++ b/postgis_fn.c
@@ -11,6 +11,9 @@
  *
  **********************************************************************
  * $Log$
+ * Revision 1.29  2003/10/28 16:57:35  strk
+ * Added collect_garray() function.
+ *
  * Revision 1.28  2003/10/28 15:16:17  strk
  * unite_sfunc() from postgis_geos.c renamed to geom_accum() and moved in postgis_fn.c
  *
@@ -2675,6 +2678,165 @@ Datum geom_accum(PG_FUNCTION_ARGS)
 
 }
 
+/*
+ * collect_garray ( GEOMETRY[] ) returns a geometry which contains
+ * all the sub_objects from all of the geometries in given array.
+ *
+ * returned geometry is the simplest possible, based on the types
+ * of the collected objects
+ * ie. if all are of either X or multiX, then a multiX is returned
+ * bboxonly types are treated as null geometries (no sub_objects)
+ */
+PG_FUNCTION_INFO_V1( collect_garray );
+Datum collect_garray ( PG_FUNCTION_ARGS )
+{
+       Datum datum;
+       ArrayType *array;
+       int nelems, srid=-1, is3d=0;
+       GEOMETRY **geoms;
+       GEOMETRY *result=NULL, *geom, *tmp;
+       int i, o;
+       BOX3D *bbox;
+
+       /* Get input datum */
+       datum = PG_GETARG_DATUM(0);
+
+       /* Return null on null input */
+       if ( (Pointer *)datum == NULL ) PG_RETURN_NULL();
+
+       /* Get actual ArrayType */
+       array = (ArrayType *) PG_DETOAST_DATUM(datum);
+
+       /* Get number of geometries in array */
+       nelems = ArrayGetNItems(ARR_NDIM(array), ARR_DIMS(array));
+
+       /* Return null on 0-elements input array */
+       if ( nelems == 0 ) PG_RETURN_NULL();
+
+       /* Get pointer to GEOMETRY pointers array */
+       geoms = (GEOMETRY **)ARR_DATA_PTR(array);
+
+       /* Return the only present element of a 1-element array */
+       if ( nelems == 1 ) PG_RETURN_POINTER(geoms[0]);
+
+       /* Iterate over all geometries in array */
+       for (i=0; i<nelems; i++)
+       {
+               int32 *offsets;
+
+               geom = geoms[i];
+
+               /* Skip NULL array elements (are them possible?) */
+               if ( geom == NULL ) continue; 
+
+               /* Use first NOT-NULL GEOMETRY as the base */
+               if ( ! result )
+               {
+                       /* Remember first geometry's SRID for later checks */
+                       srid = geom->SRID;
+
+                       /* Get first geometry's is3d flag as base is3d */
+                       is3d = geom->is3d;
+
+                       result = (GEOMETRY *)palloc(geom->size);
+                       if ( ! result ) {
+       elog(ERROR, "collect_garray: out of virtual memory");
+       PG_RETURN_NULL();
+                       }
+                       memcpy(result, geom, geom->size);
+                       
+                       /* 
+                        * I belive memory associated with geometries
+                        * in array can be safely removed. Comment
+                        * this out if you get memory faults!
+                        * TODO: inspect this (as long as passed
+                        * array is the result of geom_accum this
+                        * is true because geom_accum will DETOAST_COPY
+                        * while for direct user call I do not know)
+                        */
+                       pfree(geom);
+
+                       continue;
+               } 
+
+               /* Skip geometry if it contains no sub-objects */
+               if ( ! geom->nobjs )
+               {
+                       if ( geom->is3d ) is3d = 1; // should I care ?
+                       pfree(geom); // se note above
+                       continue;
+               }
+
+               /*
+                * If we are here this means we are in front of a
+                * good (non empty) geometry beside the first
+                */
+
+               /* Fist let's check for SRID compatibility */
+               if ( geom->SRID != srid )
+               {
+       elog(ERROR, "Operation on GEOMETRIES with different SRIDs");
+       PG_RETURN_NULL();
+               }
+
+               /*
+                * Set result is3d flag to true if at least one 
+                * of geometries in set has is set to true
+                */
+               if ( geom->is3d ) is3d = 1; 
+
+               /* Get to sub-objects offset */
+               offsets = (int32 *)(((char *)&(geom->objType[0])) +
+                               sizeof(int32) * geom->nobjs ) ;
+
+               /* Iterate over geometry sub-objects */
+               for (o=0; o<geom->nobjs; o++)
+               {
+                       int size, type;
+                       char *obj;
+
+                       /* Get object pointer */
+                       obj = (char *) geom+offsets[o];
+
+                       /* Get object type */
+                       type = geom->objType[o];
+
+                       /* Get object size (fast way) */
+                       if( o == geom->nobjs-1 ) {
+                               size = geom->size - offsets[o];
+                       } else {
+                               size = offsets[o+1] - offsets[o];
+                       }
+
+                       /*
+                        * Add sub-object to base geometry,
+                        * replace base geometry with new one.
+                        */
+                       tmp = add_to_geometry(result, size, obj, type);
+                       pfree( result );
+                       result = tmp;
+               }
+               pfree(geom); // se note above
+       }
+
+       /* Check we got something in our result */
+       if ( result == NULL ) PG_RETURN_NULL();
+
+       /*
+        * We should now have a big fat geometry composed of all
+        * sub-objects from all geometries in array
+        */
+
+       /* Set is3d flag */
+       result->is3d = is3d;
+
+       /* Construct bounding volume */
+       bbox = bbox_of_geometry( result ); // make 
+       memcpy( &result->bvol, bbox, sizeof(BOX3D) ); // copy 
+       pfree( bbox ); // release
+
+       PG_RETURN_POINTER( result );
+}
 
 // collector( geom, geom ) returns a geometry which contains
 // all the sub_objects from both of the argument geometries