PostGIS  3.0.0dev-r@@SVN_REVISION@@

◆ lwt_AddIsoEdge()

LWT_ELEMID lwt_AddIsoEdge ( LWT_TOPOLOGY topo,
LWT_ELEMID  startNode,
LWT_ELEMID  endNode,
const LWLINE geom 
)

Add an isolated edge connecting two existing isolated nodes.

For ST_AddIsoEdge

Parameters
topothe topology to operate on
start_nodeidentifier of the starting node
end_nodeidentifier of the ending node
geomthe edge geometry
Returns
ID of the newly added edge, or -1 on error (liblwgeom error handler will be invoked with error message)

Definition at line 769 of file lwgeom_topo.c.

References _lwt_CheckEdgeCrossing(), _lwt_release_nodes(), LWT_TOPOLOGY_T::be_iface, LWT_ISO_NODE::containing_face, LWT_ISO_EDGE::edge_id, LWT_ISO_EDGE::end_node, LWT_ISO_EDGE::face_left, LWT_ISO_EDGE::face_right, LWT_ISO_NODE::geom, LWT_ISO_EDGE::geom, getPoint2d_p(), lwerror(), lwgeom_is_simple(), lwline_as_lwgeom(), lwt_be_getNextEdgeId(), lwt_be_getNodeById(), lwt_be_insertEdges(), lwt_be_lastErrorMessage(), lwt_be_updateNodesById(), LWT_COL_NODE_ALL, LWT_COL_NODE_CONTAINING_FACE, LWT_ISO_EDGE::next_left, LWT_ISO_EDGE::next_right, LWT_ISO_NODE::node_id, POINTARRAY::npoints, p2d_same(), LWPOINT::point, LWLINE::points, and LWT_ISO_EDGE::start_node.

771 {
772  int num_nodes;
773  int i;
774  LWT_ISO_EDGE newedge;
775  LWT_ISO_NODE *endpoints;
776  LWT_ELEMID containing_face = -1;
777  LWT_ELEMID node_ids[2];
778  LWT_ISO_NODE updated_nodes[2];
779  int skipISOChecks = 0;
780  POINT2D p1, p2;
781 
782  /* NOT IN THE SPECS:
783  * A closed edge is never isolated (as it forms a face)
784  */
785  if ( startNode == endNode )
786  {
787  lwerror("Closed edges would not be isolated, try lwt_AddEdgeNewFaces");
788  return -1;
789  }
790 
791  if ( ! skipISOChecks )
792  {
793  /* Acurve must be simple */
794  if ( ! lwgeom_is_simple(lwline_as_lwgeom(geom)) )
795  {
796  lwerror("SQL/MM Spatial exception - curve not simple");
797  return -1;
798  }
799  }
800 
801  /*
802  * Check for:
803  * existence of nodes
804  * nodes faces match
805  * Extract:
806  * nodes face id
807  * nodes geoms
808  */
809  num_nodes = 2;
810  node_ids[0] = startNode;
811  node_ids[1] = endNode;
812  endpoints = lwt_be_getNodeById( topo, node_ids, &num_nodes,
814  if ( num_nodes < 0 )
815  {
816  lwerror("Backend error: %s", lwt_be_lastErrorMessage(topo->be_iface));
817  return -1;
818  }
819  else if ( num_nodes < 2 )
820  {
821  if ( num_nodes ) _lwt_release_nodes(endpoints, num_nodes);
822  lwerror("SQL/MM Spatial exception - non-existent node");
823  return -1;
824  }
825  for ( i=0; i<num_nodes; ++i )
826  {
827  const LWT_ISO_NODE *n = &(endpoints[i]);
828  if ( n->containing_face == -1 )
829  {
830  _lwt_release_nodes(endpoints, num_nodes);
831  lwerror("SQL/MM Spatial exception - not isolated node");
832  return -1;
833  }
834  if ( containing_face == -1 ) containing_face = n->containing_face;
835  else if ( containing_face != n->containing_face )
836  {
837  _lwt_release_nodes(endpoints, num_nodes);
838  lwerror("SQL/MM Spatial exception - nodes in different faces");
839  return -1;
840  }
841 
842  if ( ! skipISOChecks )
843  {
844  if ( n->node_id == startNode )
845  {
846  /* l) Check that start point of acurve match start node geoms. */
847  getPoint2d_p(geom->points, 0, &p1);
848  getPoint2d_p(n->geom->point, 0, &p2);
849  if ( ! p2d_same(&p1, &p2) )
850  {
851  _lwt_release_nodes(endpoints, num_nodes);
852  lwerror("SQL/MM Spatial exception - "
853  "start node not geometry start point.");
854  return -1;
855  }
856  }
857  else
858  {
859  /* m) Check that end point of acurve match end node geoms. */
860  getPoint2d_p(geom->points, geom->points->npoints-1, &p1);
861  getPoint2d_p(n->geom->point, 0, &p2);
862  if ( ! p2d_same(&p1, &p2) )
863  {
864  _lwt_release_nodes(endpoints, num_nodes);
865  lwerror("SQL/MM Spatial exception - "
866  "end node not geometry end point.");
867  return -1;
868  }
869  }
870  }
871  }
872 
873  if ( num_nodes ) _lwt_release_nodes(endpoints, num_nodes);
874 
875  if ( ! skipISOChecks )
876  {
877  if ( _lwt_CheckEdgeCrossing( topo, startNode, endNode, geom, 0 ) )
878  {
879  /* would have called lwerror already, leaking :( */
880  return -1;
881  }
882  }
883 
884  /*
885  * All checks passed, time to prepare the new edge
886  */
887 
888  newedge.edge_id = lwt_be_getNextEdgeId( topo );
889  if ( newedge.edge_id == -1 ) {
890  lwerror("Backend error: %s", lwt_be_lastErrorMessage(topo->be_iface));
891  return -1;
892  }
893 
894  /* TODO: this should likely be an exception instead ! */
895  if ( containing_face == -1 ) containing_face = 0;
896 
897  newedge.start_node = startNode;
898  newedge.end_node = endNode;
899  newedge.face_left = newedge.face_right = containing_face;
900  newedge.next_left = -newedge.edge_id;
901  newedge.next_right = newedge.edge_id;
902  newedge.geom = (LWLINE *)geom; /* const cast.. */
903 
904  int ret = lwt_be_insertEdges(topo, &newedge, 1);
905  if ( ret == -1 ) {
906  lwerror("Backend error: %s", lwt_be_lastErrorMessage(topo->be_iface));
907  return -1;
908  } else if ( ret == 0 ) {
909  lwerror("Insertion of split edge failed (no reason)");
910  return -1;
911  }
912 
913  /*
914  * Update Node containing_face values
915  *
916  * the nodes anode and anothernode are no more isolated
917  * because now there is an edge connecting them
918  */
919  updated_nodes[0].node_id = startNode;
920  updated_nodes[0].containing_face = -1;
921  updated_nodes[1].node_id = endNode;
922  updated_nodes[1].containing_face = -1;
923  ret = lwt_be_updateNodesById(topo, updated_nodes, 2,
925  if ( ret == -1 ) {
926  lwerror("Backend error: %s", lwt_be_lastErrorMessage(topo->be_iface));
927  return -1;
928  }
929 
930  return newedge.edge_id;
931 }
static int _lwt_CheckEdgeCrossing(LWT_TOPOLOGY *topo, LWT_ELEMID start_node, LWT_ELEMID end_node, const LWLINE *geom, LWT_ELEMID myself)
Definition: lwgeom_topo.c:600
static void _lwt_release_nodes(LWT_ISO_NODE *nodes, int num_nodes)
Definition: lwgeom_topo.c:466
LWT_ELEMID face_left
#define LWT_COL_NODE_CONTAINING_FACE
LWT_ELEMID containing_face
LWPOINT * geom
LWLINE * geom
POINTARRAY * point
Definition: liblwgeom.h:413
LWT_ELEMID next_left
int p2d_same(const POINT2D *p1, const POINT2D *p2)
Definition: lwalgorithm.c:49
LWGEOM * lwline_as_lwgeom(const LWLINE *obj)
Definition: lwgeom.c:321
const LWT_BE_IFACE * be_iface
LWT_ELEMID face_right
LWT_ELEMID node_id
LWT_ELEMID edge_id
static int lwt_be_updateNodesById(LWT_TOPOLOGY *topo, const LWT_ISO_NODE *nodes, int numnodes, int upd_fields)
Definition: lwgeom_topo.c:313
LWT_ELEMID lwt_be_getNextEdgeId(LWT_TOPOLOGY *topo)
Definition: lwgeom_topo.c:218
int getPoint2d_p(const POINTARRAY *pa, uint32_t n, POINT2D *point)
Definition: lwgeom_api.c:337
int lwt_be_insertEdges(LWT_TOPOLOGY *topo, LWT_ISO_EDGE *edge, int numelems)
Definition: lwgeom_topo.c:267
#define LWT_COL_NODE_ALL
LWT_ELEMID start_node
int lwgeom_is_simple(const LWGEOM *lwgeom)
LWT_ELEMID next_right
LWT_INT64 LWT_ELEMID
Identifier of topology element.
LWT_ISO_NODE * lwt_be_getNodeById(LWT_TOPOLOGY *topo, const LWT_ELEMID *ids, int *numelems, int fields)
Definition: lwgeom_topo.c:155
LWT_ELEMID end_node
const char * lwt_be_lastErrorMessage(const LWT_BE_IFACE *be)
Definition: lwgeom_topo.c:119
void lwerror(const char *fmt,...)
Write a notice out to the error handler.
Definition: lwutil.c:190
POINTARRAY * points
Definition: liblwgeom.h:424
uint32_t npoints
Definition: liblwgeom.h:373
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