_lwt_RemEdge()

static LWT_ELEMID _lwt_RemEdge ( LWT_TOPOLOGY *  topo, LWT_ELEMID  edge_id, int  modFace  )

static

Definition at line 3940 of file lwgeom_topo.c.

References _lwt_release_edges(), _lwt_release_faces(), _lwt_UpdateEdgeFaceRef(), _lwt_UpdateNodeFaceRef(), LWT_TOPOLOGY_T::be_iface, LWT_ISO_NODE::containing_face, LWT_ISO_EDGE::edge_id, LWT_ISO_EDGE::end_node, LWT_ISO_FACE::face_id, LWT_ISO_EDGE::face_left, LWT_ISO_EDGE::face_right, gbox_merge(), LWDEBUG, LWDEBUGF, lwerror(), lwfree(), lwt_be_checkTopoGeomRemEdge(), lwt_be_deleteEdges(), lwt_be_deleteFacesById(), lwt_be_getEdgeById(), lwt_be_getEdgeByNode(), lwt_be_getFaceById(), lwt_be_insertFaces(), lwt_be_lastErrorMessage(), lwt_be_updateEdgesById(), lwt_be_updateFacesById(), lwt_be_updateNodesById(), lwt_be_updateTopoGeomFaceHeal(), LWT_COL_EDGE_ALL, LWT_COL_EDGE_EDGE_ID, LWT_COL_EDGE_END_NODE, LWT_COL_EDGE_NEXT_LEFT, LWT_COL_EDGE_NEXT_RIGHT, LWT_COL_EDGE_START_NODE, LWT_COL_FACE_ALL, LWT_COL_NODE_CONTAINING_FACE, LWTFMT_ELEMID, LWT_ISO_FACE::mbr, LWT_ISO_EDGE::next_left, LWT_ISO_EDGE::next_right, LWT_ISO_NODE::node_id, and LWT_ISO_EDGE::start_node.

Referenced by lwt_RemEdgeModFace(), and lwt_RemEdgeNewFace().

{
  int i, nedges, nfaces, fields;
  LWT_ISO_EDGE *edge = NULL;
  LWT_ISO_EDGE *upd_edge = NULL;
  LWT_ISO_EDGE upd_edge_left[2];
  int nedge_left = 0;
  LWT_ISO_EDGE upd_edge_right[2];
  int nedge_right = 0;
  LWT_ISO_NODE upd_node[2];
  int nnode = 0;
  LWT_ISO_FACE *faces = NULL;
  LWT_ISO_FACE newface;
  LWT_ELEMID node_ids[2];
  LWT_ELEMID face_ids[2];
  int fnode_edges = 0; /* number of edges on the first node (excluded
                        * the one being removed ) */
  int lnode_edges = 0; /* number of edges on the last node (excluded
                        * the one being removed ) */

  newface.face_id = 0;

  i = 1;
  edge = lwt_be_getEdgeById(topo, &edge_id, &i, LWT_COL_EDGE_ALL);
  if ( ! edge )
  {
    LWDEBUGF(1, "lwt_be_getEdgeById returned NULL and set i=%d", i);
    if ( i == -1 )
    {
      lwerror("Backend error: %s", lwt_be_lastErrorMessage(topo->be_iface));
      return -1;
    }
    else if ( i == 0 )
    {
      lwerror("SQL/MM Spatial exception - non-existent edge %"
              LWTFMT_ELEMID, edge_id);
      return -1;
    }
    else
    {
      lwerror("Backend coding error: getEdgeById callback returned NULL "
              "but numelements output parameter has value %d "
              "(expected 0 or 1)", i);
      return -1;
    }
  }

  if ( ! lwt_be_checkTopoGeomRemEdge(topo, edge_id,
                                     edge->face_left, edge->face_right) )
  {
    lwerror("%s", lwt_be_lastErrorMessage(topo->be_iface));
    return -1;
  }

  LWDEBUG(1, "Updating next_{right,left}_face of ring edges...");

  /* Update edge linking */

  nedges = 0;
  node_ids[nedges++] = edge->start_node;
  if ( edge->end_node != edge->start_node )
  {
    node_ids[nedges++] = edge->end_node;
  }
  fields = LWT_COL_EDGE_EDGE_ID | LWT_COL_EDGE_START_NODE |
           LWT_COL_EDGE_END_NODE | LWT_COL_EDGE_NEXT_LEFT |
           LWT_COL_EDGE_NEXT_RIGHT;
  upd_edge = lwt_be_getEdgeByNode( topo, &(node_ids[0]), &nedges, fields );
  if ( nedges == -1 ) {
    lwerror("Backend error: %s", lwt_be_lastErrorMessage(topo->be_iface));
    return -1;
  }
  nedge_left = nedge_right = 0;
  for ( i=0; i<nedges; ++i )
  {
    LWT_ISO_EDGE *e = &(upd_edge[i]);
    if ( e->edge_id == edge_id ) continue;
    if ( e->start_node == edge->start_node || e->end_node == edge->start_node )
    {
      ++fnode_edges;
    }
    if ( e->start_node == edge->end_node || e->end_node == edge->end_node )
    {
      ++lnode_edges;
    }
    if ( e->next_left == -edge_id )
    {
      upd_edge_left[nedge_left].edge_id = e->edge_id;
      upd_edge_left[nedge_left++].next_left =
        edge->next_left != edge_id ? edge->next_left : edge->next_right;
    }
    else if ( e->next_left == edge_id )
    {
      upd_edge_left[nedge_left].edge_id = e->edge_id;
      upd_edge_left[nedge_left++].next_left =
        edge->next_right != -edge_id ? edge->next_right : edge->next_left;
    }

    if ( e->next_right == -edge_id )
    {
      upd_edge_right[nedge_right].edge_id = e->edge_id;
      upd_edge_right[nedge_right++].next_right =
        edge->next_left != edge_id ? edge->next_left : edge->next_right;
    }
    else if ( e->next_right == edge_id )
    {
      upd_edge_right[nedge_right].edge_id = e->edge_id;
      upd_edge_right[nedge_right++].next_right =
        edge->next_right != -edge_id ? edge->next_right : edge->next_left;
    }
  }

  if ( nedge_left )
  {
    LWDEBUGF(1, "updating %d 'next_left' edges", nedge_left);
    /* update edges in upd_edge_left set next_left */
    i = lwt_be_updateEdgesById(topo, &(upd_edge_left[0]), nedge_left,
                               LWT_COL_EDGE_NEXT_LEFT);
    if ( i == -1 )
    {
      _lwt_release_edges(edge, 1);
      lwfree(upd_edge);
      lwerror("Backend error: %s", lwt_be_lastErrorMessage(topo->be_iface));
      return -1;
    }
  }
  if ( nedge_right )
  {
    LWDEBUGF(1, "updating %d 'next_right' edges", nedge_right);
    /* update edges in upd_edge_right set next_right */
    i = lwt_be_updateEdgesById(topo, &(upd_edge_right[0]), nedge_right,
                               LWT_COL_EDGE_NEXT_RIGHT);
    if ( i == -1 )
    {
      _lwt_release_edges(edge, 1);
      lwfree(upd_edge);
      lwerror("Backend error: %s", lwt_be_lastErrorMessage(topo->be_iface));
      return -1;
    }
  }
  LWDEBUGF(1, "releasing %d updateable edges in %p", nedges, upd_edge);
  lwfree(upd_edge);

  /* Id of face that will take up all the space previously
   * taken by left and right faces of the edge */
  LWT_ELEMID floodface;

  /* Find floodface, and update its mbr if != 0 */
  if ( edge->face_left == edge->face_right )
  {
    floodface = edge->face_right;
  }
  else
  {
    /* Two faces healed */
    if ( edge->face_left == 0 || edge->face_right == 0 )
    {
      floodface = 0;
      LWDEBUG(1, "floodface is universe");
    }
    else
    {
      /* we choose right face as the face that will remain
       * to be symmetric with ST_AddEdgeModFace */
      floodface = edge->face_right;
      LWDEBUGF(1, "floodface is %" LWTFMT_ELEMID, floodface);
      /* update mbr of floodface as union of mbr of both faces */
      face_ids[0] = edge->face_left;
      face_ids[1] = edge->face_right;
      nfaces = 2;
      fields = LWT_COL_FACE_ALL;
      faces = lwt_be_getFaceById(topo, face_ids, &nfaces, fields);
      if ( nfaces == -1 ) {
        lwerror("Backend error: %s", lwt_be_lastErrorMessage(topo->be_iface));
        return -1;
      }
      GBOX *box1=NULL;
      GBOX *box2=NULL;
      for ( i=0; i<nfaces; ++i )
      {
        if ( faces[i].face_id == edge->face_left )
        {
          if ( ! box1 ) box1 = faces[i].mbr;
          else
          {
            i = edge->face_left;
            _lwt_release_edges(edge, 1);
            _lwt_release_faces(faces, nfaces);
            lwerror("corrupted topology: more than 1 face have face_id=%"
                    LWTFMT_ELEMID, i);
            return -1;
          }
        }
        else if ( faces[i].face_id == edge->face_right )
        {
          if ( ! box2 ) box2 = faces[i].mbr;
          else
          {
            i = edge->face_right;
            _lwt_release_edges(edge, 1);
            _lwt_release_faces(faces, nfaces);
            lwerror("corrupted topology: more than 1 face have face_id=%"
                    LWTFMT_ELEMID, i);
            return -1;
          }
        }
        else
        {
          i = faces[i].face_id;
          _lwt_release_edges(edge, 1);
          _lwt_release_faces(faces, nfaces);
          lwerror("Backend coding error: getFaceById returned face "
                  "with non-requested id %" LWTFMT_ELEMID, i);
          return -1;
        }
      }
      if ( ! box1 ) {
        i = edge->face_left;
        _lwt_release_edges(edge, 1);
        _lwt_release_faces(faces, nfaces);
        lwerror("corrupted topology: no face have face_id=%"
                LWTFMT_ELEMID " (left face for edge %"
                LWTFMT_ELEMID ")", i, edge_id);
        return -1;
      }
      if ( ! box2 ) {
        i = edge->face_right;
        _lwt_release_edges(edge, 1);
        _lwt_release_faces(faces, nfaces);
        lwerror("corrupted topology: no face have face_id=%"
                LWTFMT_ELEMID " (right face for edge %"
                LWTFMT_ELEMID ")", i, edge_id);
        return -1;
      }
      gbox_merge(box2, box1); /* box1 is now the union of the two */
      newface.mbr = box1;
      if ( modFace )
      {
        newface.face_id = floodface;
        i = lwt_be_updateFacesById( topo, &newface, 1 );
        _lwt_release_faces(faces, 2);
        if ( i == -1 )
        {
          _lwt_release_edges(edge, 1);
          lwerror("Backend error: %s", lwt_be_lastErrorMessage(topo->be_iface));
          return -1;
        }
        if ( i != 1 )
        {
          _lwt_release_edges(edge, 1);
          lwerror("Unexpected error: %d faces updated when expecting 1", i);
          return -1;
        }
      }
      else
      {
        /* New face replaces the old two faces */
        newface.face_id = -1;
        i = lwt_be_insertFaces( topo, &newface, 1 );
        _lwt_release_faces(faces, 2);
        if ( i == -1 )
        {
          _lwt_release_edges(edge, 1);
          lwerror("Backend error: %s", lwt_be_lastErrorMessage(topo->be_iface));
          return -1;
        }
        if ( i != 1 )
        {
          _lwt_release_edges(edge, 1);
          lwerror("Unexpected error: %d faces inserted when expecting 1", i);
          return -1;
        }
        floodface = newface.face_id;
      }
    }

    /* Update face references for edges and nodes still referencing
     * the removed face(s) */

    if ( edge->face_left != floodface )
    {
      if ( -1 == _lwt_UpdateEdgeFaceRef(topo, edge->face_left, floodface) )
      {
        _lwt_release_edges(edge, 1);
        lwerror("Backend error: %s", lwt_be_lastErrorMessage(topo->be_iface));
        return -1;
      }
      if ( -1 == _lwt_UpdateNodeFaceRef(topo, edge->face_left, floodface) )
      {
        _lwt_release_edges(edge, 1);
        lwerror("Backend error: %s", lwt_be_lastErrorMessage(topo->be_iface));
        return -1;
      }
    }

    if ( edge->face_right != floodface )
    {
      if ( -1 == _lwt_UpdateEdgeFaceRef(topo, edge->face_right, floodface) )
      {
        _lwt_release_edges(edge, 1);
        lwerror("Backend error: %s", lwt_be_lastErrorMessage(topo->be_iface));
        return -1;
      }
      if ( -1 == _lwt_UpdateNodeFaceRef(topo, edge->face_right, floodface) )
      {
        _lwt_release_edges(edge, 1);
        lwerror("Backend error: %s", lwt_be_lastErrorMessage(topo->be_iface));
        return -1;
      }
    }

    /* Update topogeoms on heal */
    if ( ! lwt_be_updateTopoGeomFaceHeal(topo,
                                  edge->face_right, edge->face_left,
                                  floodface) )
    {
      _lwt_release_edges(edge, 1);
      lwerror("%s", lwt_be_lastErrorMessage(topo->be_iface));
      return -1;
    }
  } /* two faces healed */

  /* Delete the edge */
  i = lwt_be_deleteEdges(topo, edge, LWT_COL_EDGE_EDGE_ID);
  if ( i == -1 ) {
    _lwt_release_edges(edge, 1);
    lwerror("Backend error: %s", lwt_be_lastErrorMessage(topo->be_iface));
    return -1;
  }

  /* If any of the edge nodes remained isolated, set
   * containing_face = floodface
   */
  if ( ! fnode_edges )
  {
    upd_node[nnode].node_id = edge->start_node;
    upd_node[nnode].containing_face = floodface;
    ++nnode;
  }
  if ( edge->end_node != edge->start_node && ! lnode_edges )
  {
    upd_node[nnode].node_id = edge->end_node;
    upd_node[nnode].containing_face = floodface;
    ++nnode;
  }
  if ( nnode )
  {
    i = lwt_be_updateNodesById(topo, upd_node, nnode,
                               LWT_COL_NODE_CONTAINING_FACE);
    if ( i == -1 ) {
      _lwt_release_edges(edge, 1);
      lwerror("Backend error: %s", lwt_be_lastErrorMessage(topo->be_iface));
      return -1;
    }
  }

  if ( edge->face_left != edge->face_right )
  /* or there'd be no face to remove */
  {
    LWT_ELEMID ids[2];
    int nids = 0;
    if ( edge->face_right != floodface )
      ids[nids++] = edge->face_right;
    if ( edge->face_left != floodface )
      ids[nids++] = edge->face_left;
    i = lwt_be_deleteFacesById(topo, ids, nids);
    if ( i == -1 ) {
      _lwt_release_edges(edge, 1);
      lwerror("Backend error: %s", lwt_be_lastErrorMessage(topo->be_iface));
      return -1;
    }
  }

  _lwt_release_edges(edge, 1);
  return modFace ? floodface : newface.face_id;
}

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