]> git.mxchange.org Git - flightgear.git/blobdiff - src/Airports/groundnetwork.cxx
Assigned an ATC controller to the user's Aircraft and change the comm1 radio frequenc...
[flightgear.git] / src / Airports / groundnetwork.cxx
index 321a3af68833c7212d8f67d037e6b3e651d872e5..0470e4af92ef9a28663887cd57e42fc90d404924 100644 (file)
 #include <simgear/debug/logstream.hxx>
 #include <simgear/route/waypoint.hxx>
 
+#include <Airports/simple.hxx>
 #include <Airports/dynamics.hxx>
 
+#include <AIModel/AIAircraft.hxx>
 #include <AIModel/AIFlightPlan.hxx>
 
 #include "groundnetwork.hxx"
  * FGTaxiSegment
  **************************************************************************/
 
-void FGTaxiSegment::setStart(FGTaxiNodeVector *nodes)
+void FGTaxiSegment::setStart(FGTaxiNodeVector * nodes)
 {
-  FGTaxiNodeVectorIterator i = nodes->begin();
-  while (i != nodes->end())
-    {
-      //cerr << "Scanning start node index" << (*i)->getIndex() << endl;
-      if ((*i)->getIndex() == startNode)
-       {
-         start = (*i)->getAddress();
-         (*i)->addSegment(this);
-         return;
-       }
-      i++;
-    }
-  SG_LOG(SG_GENERAL, SG_ALERT,  "Could not find start node " << startNode << endl);
+    FGTaxiNodeVectorIterator i = nodes->begin();
+    while (i != nodes->end()) {
+        //cerr << "Scanning start node index" << (*i)->getIndex() << endl;
+        if ((*i)->getIndex() == startNode) {
+            start = (*i)->getAddress();
+            (*i)->addSegment(this);
+            return;
+        }
+        i++;
+    }
+    SG_LOG(SG_GENERAL, SG_ALERT,
+           "Could not find start node " << startNode << endl);
 }
 
-void FGTaxiSegment::setEnd(FGTaxiNodeVector *nodes)
+void FGTaxiSegment::setEnd(FGTaxiNodeVector * nodes)
 {
-  FGTaxiNodeVectorIterator i = nodes->begin();
-  while (i != nodes->end())
-    {
-      //cerr << "Scanning end node index" << (*i)->getIndex() << endl;
-      if ((*i)->getIndex() == endNode)
-       {
-         end = (*i)->getAddress();
-         return;
-       }
-      i++;
-    }
-  SG_LOG(SG_GENERAL, SG_ALERT,  "Could not find end node " << endNode << endl);
+    FGTaxiNodeVectorIterator i = nodes->begin();
+    while (i != nodes->end()) {
+        //cerr << "Scanning end node index" << (*i)->getIndex() << endl;
+        if ((*i)->getIndex() == endNode) {
+            end = (*i)->getAddress();
+            return;
+        }
+        i++;
+    }
+    SG_LOG(SG_GENERAL, SG_ALERT,
+           "Could not find end node " << endNode << endl);
 }
 
 
@@ -79,90 +79,91 @@ void FGTaxiSegment::setEnd(FGTaxiNodeVector *nodes)
 // doing this.
 void FGTaxiSegment::setTrackDistance()
 {
-  length = SGGeodesy::distanceM(start->getGeod(), end->getGeod());
+    length = SGGeodesy::distanceM(start->getGeod(), end->getGeod());
 }
 
 
 void FGTaxiSegment::setCourseDiff(double crse)
 {
-  headingDiff = fabs(course-crse);
-  
-  if (headingDiff > 180)
-    headingDiff = fabs(headingDiff - 360);
+    headingDiff = fabs(course - crse);
+
+    if (headingDiff > 180)
+        headingDiff = fabs(headingDiff - 360);
 }
 
 
 /***************************************************************************
  * FGTaxiRoute
  **************************************************************************/
-bool FGTaxiRoute::next(int *nde) 
-{ 
-  //for (intVecIterator i = nodes.begin(); i != nodes.end(); i++)
-  //  cerr << "FGTaxiRoute contains : " << *(i) << endl;
-  //cerr << "Offset from end: " << nodes.end() - currNode << endl;
-  //if (currNode != nodes.end())
-  //  cerr << "true" << endl;
-  //else
-  //  cerr << "false" << endl;
-  //if (nodes.size() != (routes.size()) +1)
-  //  cerr << "ALERT: Misconfigured TaxiRoute : " << nodes.size() << " " << routes.size() << endl;
-      
-  if (currNode == nodes.end())
-    return false;
-  *nde = *(currNode); 
-  if (currNode != nodes.begin()) // make sure route corresponds to the end node
-    currRoute++;
-  currNode++;
-  return true;
+bool FGTaxiRoute::next(int *nde)
+{
+    //for (intVecIterator i = nodes.begin(); i != nodes.end(); i++)
+    //  cerr << "FGTaxiRoute contains : " << *(i) << endl;
+    //cerr << "Offset from end: " << nodes.end() - currNode << endl;
+    //if (currNode != nodes.end())
+    //  cerr << "true" << endl;
+    //else
+    //  cerr << "false" << endl;
+    //if (nodes.size() != (routes.size()) +1)
+    //  cerr << "ALERT: Misconfigured TaxiRoute : " << nodes.size() << " " << routes.size() << endl;
+
+    if (currNode == nodes.end())
+        return false;
+    *nde = *(currNode);
+    if (currNode != nodes.begin())      // make sure route corresponds to the end node
+        currRoute++;
+    currNode++;
+    return true;
 };
 
-bool FGTaxiRoute::next(int *nde, int *rte) 
-{ 
-  //for (intVecIterator i = nodes.begin(); i != nodes.end(); i++)
-  //  cerr << "FGTaxiRoute contains : " << *(i) << endl;
-  //cerr << "Offset from end: " << nodes.end() - currNode << endl;
-  //if (currNode != nodes.end())
-  //  cerr << "true" << endl;
-  //else
-  //  cerr << "false" << endl;
-  if (nodes.size() != (routes.size()) +1) {
-    SG_LOG(SG_GENERAL, SG_ALERT, "ALERT: Misconfigured TaxiRoute : " << nodes.size() << " " << routes.size());
-    exit(1);
-  }
-  if (currNode == nodes.end())
-    return false;
-  *nde = *(currNode); 
-  //*rte = *(currRoute);
-  if (currNode != nodes.begin()) // Make sure route corresponds to the end node
-    {
-      *rte = *(currRoute);
-      currRoute++;
+bool FGTaxiRoute::next(int *nde, int *rte)
+{
+    //for (intVecIterator i = nodes.begin(); i != nodes.end(); i++)
+    //  cerr << "FGTaxiRoute contains : " << *(i) << endl;
+    //cerr << "Offset from end: " << nodes.end() - currNode << endl;
+    //if (currNode != nodes.end())
+    //  cerr << "true" << endl;
+    //else
+    //  cerr << "false" << endl;
+    if (nodes.size() != (routes.size()) + 1) {
+        SG_LOG(SG_GENERAL, SG_ALERT,
+               "ALERT: Misconfigured TaxiRoute : " << nodes.
+               size() << " " << routes.size());
+        exit(1);
     }
-  else
+    if (currNode == nodes.end())
+        return false;
+    *nde = *(currNode);
+    //*rte = *(currRoute);
+    if (currNode != nodes.begin())      // Make sure route corresponds to the end node
     {
-      // If currNode points to the first node, this means the aircraft is not on the taxi node
-      // yet. Make sure to return a unique identifyer in this situation though, because otherwise
-      // the speed adjust AI code may be unable to resolve whether two aircraft are on the same 
-      // taxi route or not. the negative of the preceding route seems a logical choice, as it is 
-      // unique for any starting location. 
-      // Note that this is probably just a temporary fix until I get Parking / tower control working.
-      *rte = -1 * *(currRoute); 
-    }
-  currNode++;
-  return true;
+        *rte = *(currRoute);
+        currRoute++;
+    } else {
+        // If currNode points to the first node, this means the aircraft is not on the taxi node
+        // yet. Make sure to return a unique identifyer in this situation though, because otherwise
+        // the speed adjust AI code may be unable to resolve whether two aircraft are on the same 
+        // taxi route or not. the negative of the preceding route seems a logical choice, as it is 
+        // unique for any starting location. 
+        // Note that this is probably just a temporary fix until I get Parking / tower control working.
+        *rte = -1 * *(currRoute);
+    }
+    currNode++;
+    return true;
 };
 
 void FGTaxiRoute::rewind(int route)
 {
-  int currPoint;
-  int currRoute;
-  first();
-  do {
-    if (!(next(&currPoint, &currRoute))) { 
-      SG_LOG(SG_GENERAL,SG_ALERT, "Error in rewinding TaxiRoute: current" << currRoute 
-            << " goal " << route);
-    }
-  } while (currRoute != route);
+    int currPoint;
+    int currRoute;
+    first();
+    do {
+        if (!(next(&currPoint, &currRoute))) {
+            SG_LOG(SG_GENERAL, SG_ALERT,
+                   "Error in rewinding TaxiRoute: current" << currRoute <<
+                   " goal " << route);
+        }
+    } while (currRoute != route);
 }
 
 
@@ -171,67 +172,64 @@ void FGTaxiRoute::rewind(int route)
 /***************************************************************************
  * FGGroundNetwork()
  **************************************************************************/
-bool compare_nodes(FGTaxiNode *a, FGTaxiNode *b) {
-return (*a) < (*b);
+bool compare_nodes(FGTaxiNode * a, FGTaxiNode * b)
+{
+    return (*a) < (*b);
 }
 
-bool compare_segments(FGTaxiSegment *a, FGTaxiSegment *b) {
-return (*a) < (*b);
+bool compare_segments(FGTaxiSegment * a, FGTaxiSegment * b)
+{
+    return (*a) < (*b);
 }
 
 FGGroundNetwork::FGGroundNetwork()
 {
-  hasNetwork = false;
-  foundRoute = false;
-  totalDistance = 0;
-  maxDistance = 0;
-  //maxDepth    = 1000;
-  count       = 0;
-  currTraffic = activeTraffic.begin();
+    hasNetwork = false;
+    foundRoute = false;
+    totalDistance = 0;
+    maxDistance = 0;
+    //maxDepth    = 1000;
+    count = 0;
+    currTraffic = activeTraffic.begin();
 
 }
 
 FGGroundNetwork::~FGGroundNetwork()
 {
-  for (FGTaxiNodeVectorIterator node = nodes.begin();
-       node != nodes.end();
-       node++)
-    {
-      delete (*node);
+    for (FGTaxiNodeVectorIterator node = nodes.begin();
+         node != nodes.end(); node++) {
+        delete(*node);
     }
-  nodes.clear();
-  pushBackNodes.clear();
-  for (FGTaxiSegmentVectorIterator seg = segments.begin();
-       seg != segments.end();
-       seg++)
-    {
-      delete (*seg);
+    nodes.clear();
+    pushBackNodes.clear();
+    for (FGTaxiSegmentVectorIterator seg = segments.begin();
+         seg != segments.end(); seg++) {
+        delete(*seg);
     }
-  segments.clear();
+    segments.clear();
 }
 
-void FGGroundNetwork::addSegment(const FGTaxiSegment &seg)
+void FGGroundNetwork::addSegment(const FGTaxiSegment & seg)
 {
-  segments.push_back(new FGTaxiSegment(seg));
+    segments.push_back(new FGTaxiSegment(seg));
 }
 
-void FGGroundNetwork::addNode(const FGTaxiNode &node)
+void FGGroundNetwork::addNode(const FGTaxiNode & node)
 {
-  nodes.push_back(new FGTaxiNode(node));
+    nodes.push_back(new FGTaxiNode(node));
 }
 
-void FGGroundNetwork::addNodes(FGParkingVec *parkings)
+void FGGroundNetwork::addNodes(FGParkingVec * parkings)
 {
-  FGTaxiNode n;
-  FGParkingVecIterator i = parkings->begin();
-  while (i != parkings->end())
-    {
-      n.setIndex(i->getIndex());
-      n.setLatitude(i->getLatitude());
-      n.setLongitude(i->getLongitude());
-      nodes.push_back(new FGTaxiNode(n));
-
-      i++;
+    FGTaxiNode n;
+    FGParkingVecIterator i = parkings->begin();
+    while (i != parkings->end()) {
+        n.setIndex(i->getIndex());
+        n.setLatitude(i->getLatitude());
+        n.setLongitude(i->getLongitude());
+        nodes.push_back(new FGTaxiNode(n));
+
+        i++;
     }
 }
 
@@ -239,120 +237,117 @@ void FGGroundNetwork::addNodes(FGParkingVec *parkings)
 
 void FGGroundNetwork::init()
 {
-  hasNetwork = true;
-  int index = 1;
-  sort(nodes.begin(), nodes.end(), compare_nodes);
-  //sort(segments.begin(), segments.end(), compare_segments());
-  FGTaxiSegmentVectorIterator i = segments.begin();
-  while(i != segments.end()) {
-    (*i)->setStart(&nodes);
-    (*i)->setEnd  (&nodes);
-    (*i)->setTrackDistance();
-    (*i)->setIndex(index);
-    if ((*i)->isPushBack()) {
-          pushBackNodes.push_back((*i)->getEnd());
-    }
-    //SG_LOG(SG_GENERAL, SG_BULK,  "initializing segment " << (*i)->getIndex() << endl);
-    //SG_LOG(SG_GENERAL, SG_BULK, "Track distance = "     << (*i)->getLength() << endl);
-    //SG_LOG(SG_GENERAL, SG_BULK, "Track runs from "      << (*i)->getStart()->getIndex() << " to "
-    //                                                    << (*i)->getEnd()->getIndex() << endl);
-    i++;
-    index++;
-  }
-  i = segments.begin();
-  while(i != segments.end()) {
-    FGTaxiSegmentVectorIterator j = (*i)->getEnd()->getBeginRoute(); 
-    while (j != (*i)->getEnd()->getEndRoute())
-      {
-       if ((*j)->getEnd()->getIndex() == (*i)->getStart()->getIndex())
-         {
-//         int start1 = (*i)->getStart()->getIndex();
-//         int end1   = (*i)->getEnd()  ->getIndex();
-//         int start2 = (*j)->getStart()->getIndex();
-//         int end2   = (*j)->getEnd()->getIndex();
-//         int oppIndex = (*j)->getIndex();
-           //cerr << "Opposite of  " << (*i)->getIndex() << " (" << start1 << "," << end1 << ") "
-           //   << "happens to be " << oppIndex      << " (" << start2 << "," << end2 << ") " << endl;
-           (*i)->setOpposite(*j);
-           break;
-         }
-         j++;
-      }
-    i++;
-  }
-  //FGTaxiNodeVectorIterator j = nodes.begin();
-  //while (j != nodes.end()) {
-  //    if ((*j)->getHoldPointType() == 3) {
-  //        pushBackNodes.push_back((*j));
-  //    }
-  //    j++;
-  //}
-  //cerr << "Done initializing ground network" << endl;
-  //exit(1);
+    hasNetwork = true;
+    int index = 1;
+    sort(nodes.begin(), nodes.end(), compare_nodes);
+    //sort(segments.begin(), segments.end(), compare_segments());
+    FGTaxiSegmentVectorIterator i = segments.begin();
+    while (i != segments.end()) {
+        (*i)->setStart(&nodes);
+        (*i)->setEnd(&nodes);
+        (*i)->setTrackDistance();
+        (*i)->setIndex(index);
+        if ((*i)->isPushBack()) {
+            pushBackNodes.push_back((*i)->getEnd());
+        }
+        //SG_LOG(SG_GENERAL, SG_BULK,  "initializing segment " << (*i)->getIndex() << endl);
+        //SG_LOG(SG_GENERAL, SG_BULK, "Track distance = "     << (*i)->getLength() << endl);
+        //SG_LOG(SG_GENERAL, SG_BULK, "Track runs from "      << (*i)->getStart()->getIndex() << " to "
+        //                                                    << (*i)->getEnd()->getIndex() << endl);
+        i++;
+        index++;
+    }
+
+    i = segments.begin();
+    while (i != segments.end()) {
+        FGTaxiSegmentVectorIterator j = (*i)->getEnd()->getBeginRoute();
+        while (j != (*i)->getEnd()->getEndRoute()) {
+            if ((*j)->getEnd()->getIndex() == (*i)->getStart()->getIndex()) {
+//          int start1 = (*i)->getStart()->getIndex();
+//          int end1   = (*i)->getEnd()  ->getIndex();
+//          int start2 = (*j)->getStart()->getIndex();
+//          int end2   = (*j)->getEnd()->getIndex();
+//          int oppIndex = (*j)->getIndex();
+                //cerr << "Opposite of  " << (*i)->getIndex() << " (" << start1 << "," << end1 << ") "
+                //   << "happens to be " << oppIndex      << " (" << start2 << "," << end2 << ") " << endl;
+                (*i)->setOpposite(*j);
+                break;
+            }
+            j++;
+        }
+        i++;
+    }
+    //FGTaxiNodeVectorIterator j = nodes.begin();
+    //while (j != nodes.end()) {
+    //    if ((*j)->getHoldPointType() == 3) {
+    //        pushBackNodes.push_back((*j));
+    //    }
+    //    j++;
+    //}
+    //cerr << "Done initializing ground network" << endl;
+    //exit(1);
 }
 
-int FGGroundNetwork::findNearestNode(const SGGeod& aGeod)
+int FGGroundNetwork::findNearestNode(const SGGeod & aGeod)
 {
-  double minDist = HUGE_VAL;
-  int index = -1;
-  
-  for (FGTaxiNodeVectorIterator itr = nodes.begin(); itr != nodes.end(); itr++)
-  {
-    double d = SGGeodesy::distanceM(aGeod, (*itr)->getGeod());
-    if (d < minDist)
-    {
-      minDist = d;
-      index = (*itr)->getIndex();
-      //cerr << "Minimum distance of " << minDist << " for index " << index << endl;
+    double minDist = HUGE_VAL;
+    int index = -1;
+
+    for (FGTaxiNodeVectorIterator itr = nodes.begin(); itr != nodes.end();
+         itr++) {
+        double d = SGGeodesy::distanceM(aGeod, (*itr)->getGeod());
+        if (d < minDist) {
+            minDist = d;
+            index = (*itr)->getIndex();
+            //cerr << "Minimum distance of " << minDist << " for index " << index << endl;
+        }
     }
-  }
-  
-  return index;
+
+    return index;
 }
 
 int FGGroundNetwork::findNearestNode(double lat, double lon)
 {
-  return findNearestNode(SGGeod::fromDeg(lon, lat));
+    return findNearestNode(SGGeod::fromDeg(lon, lat));
 }
 
 FGTaxiNode *FGGroundNetwork::findNode(unsigned idx)
-{ /*
-    for (FGTaxiNodeVectorIterator 
-    itr = nodes.begin();
-    itr != nodes.end(); itr++)
-    {
-    if (itr->getIndex() == idx)
-    return itr->getAddress();
-    }*/
-  
-  if ((idx >= 0) && (idx < nodes.size())) 
-    return nodes[idx]->getAddress();
-  else
-    return 0;
+{                               /*
+                                   for (FGTaxiNodeVectorIterator 
+                                   itr = nodes.begin();
+                                   itr != nodes.end(); itr++)
+                                   {
+                                   if (itr->getIndex() == idx)
+                                   return itr->getAddress();
+                                   } */
+
+    if ((idx >= 0) && (idx < nodes.size()))
+        return nodes[idx]->getAddress();
+    else
+        return 0;
 }
 
 FGTaxiSegment *FGGroundNetwork::findSegment(unsigned idx)
-{/*
-  for (FGTaxiSegmentVectorIterator 
-        itr = segments.begin();
-       itr != segments.end(); itr++)
-    {
-      if (itr->getIndex() == idx)
-       return itr->getAddress();
-    } 
- */
-  if ((idx > 0) && (idx <= segments.size()))
-    return segments[idx-1]->getAddress();
-  else
-    {
-      //cerr << "Alert: trying to find invalid segment " << idx << endl;
-      return 0;
+{                               /*
+                                   for (FGTaxiSegmentVectorIterator 
+                                   itr = segments.begin();
+                                   itr != segments.end(); itr++)
+                                   {
+                                   if (itr->getIndex() == idx)
+                                   return itr->getAddress();
+                                   } 
+                                 */
+    if ((idx > 0) && (idx <= segments.size()))
+        return segments[idx - 1]->getAddress();
+    else {
+        //cerr << "Alert: trying to find invalid segment " << idx << endl;
+        return 0;
     }
 }
 
 
-FGTaxiRoute FGGroundNetwork::findShortestRoute(int start, int end, bool fullSearch) 
+FGTaxiRoute FGGroundNetwork::findShortestRoute(int start, int end,
+                                               bool fullSearch)
 {
 //implements Dijkstra's algorithm to find shortest distance route from start to end
 //taken from http://en.wikipedia.org/wiki/Dijkstra's_algorithm
@@ -362,38 +357,37 @@ FGTaxiRoute FGGroundNetwork::findShortestRoute(int start, int end, bool fullSear
     int nParkings = parent->getDynamics()->getNrOfParkings();
     FGTaxiNodeVector *currNodesSet;
     if (fullSearch) {
-         currNodesSet = &nodes;
+        currNodesSet = &nodes;
     } else {
-         currNodesSet = &pushBackNodes;
+        currNodesSet = &pushBackNodes;
     }
 
     for (FGTaxiNodeVectorIterator
-         itr = currNodesSet->begin();
-         itr != currNodesSet->end(); itr++) {
-            (*itr)->setPathScore(HUGE_VAL); //infinity by all practical means
-            (*itr)->setPreviousNode(0); //
-            (*itr)->setPreviousSeg (0); //
-         }
+         itr = currNodesSet->begin(); itr != currNodesSet->end(); itr++) {
+        (*itr)->setPathScore(HUGE_VAL); //infinity by all practical means
+        (*itr)->setPreviousNode(0);     //
+        (*itr)->setPreviousSeg(0);      //
+    }
 
     FGTaxiNode *firstNode = findNode(start);
     firstNode->setPathScore(0);
 
-    FGTaxiNode *lastNode  = findNode(end);
+    FGTaxiNode *lastNode = findNode(end);
 
-    FGTaxiNodeVector unvisited(*currNodesSet); // working copy
+    FGTaxiNodeVector unvisited(*currNodesSet);  // working copy
 
     while (!unvisited.empty()) {
-        FGTaxiNodebest = *(unvisited.begin());
+        FGTaxiNode *best = *(unvisited.begin());
         for (FGTaxiNodeVectorIterator
-             itr = unvisited.begin();
-             itr != unvisited.end(); itr++) {
-                 if ((*itr)->getPathScore() < best->getPathScore())
-                     best = (*itr);
+             itr = unvisited.begin(); itr != unvisited.end(); itr++) {
+            if ((*itr)->getPathScore() < best->getPathScore())
+                best = (*itr);
         }
 
-        FGTaxiNodeVectorIterator newend = remove(unvisited.begin(), unvisited.end(), best);
+        FGTaxiNodeVectorIterator newend =
+            remove(unvisited.begin(), unvisited.end(), best);
         unvisited.erase(newend, unvisited.end());
-        
+
         if (best == lastNode) { // found route or best not connected
             break;
         } else {
@@ -401,15 +395,17 @@ FGTaxiRoute FGGroundNetwork::findShortestRoute(int start, int end, bool fullSear
                  seg = best->getBeginRoute();
                  seg != best->getEndRoute(); seg++) {
                 if (fullSearch || (*seg)->isPushBack()) {
-                    FGTaxiNode* tgt = (*seg)->getEnd();
-                    double alt = best->getPathScore() + (*seg)->getLength() + (*seg)->getPenalty(nParkings);
-                    if (alt < tgt->getPathScore()) {              // Relax (u,v)
+                    FGTaxiNode *tgt = (*seg)->getEnd();
+                    double alt =
+                        best->getPathScore() + (*seg)->getLength() +
+                        (*seg)->getPenalty(nParkings);
+                    if (alt < tgt->getPathScore()) {    // Relax (u,v)
                         tgt->setPathScore(alt);
                         tgt->setPreviousNode(best);
-                        tgt->setPreviousSeg(*seg); //
-                   }
+                        tgt->setPreviousSeg(*seg);      //
+                    }
                 } else {
-                //   // cerr << "Skipping TaxiSegment " << (*seg)->getIndex() << endl;
+                    //   // cerr << "Skipping TaxiSegment " << (*seg)->getIndex() << endl;
                 }
             }
         }
@@ -417,17 +413,18 @@ FGTaxiRoute FGGroundNetwork::findShortestRoute(int start, int end, bool fullSear
 
     if (lastNode->getPathScore() == HUGE_VAL) {
         // no valid route found
-       if (fullSearch) {
-            SG_LOG( SG_GENERAL, SG_ALERT, "Failed to find route from waypoint " << start << " to " << end << " at " <<
-                    parent->getId());
+        if (fullSearch) {
+            SG_LOG(SG_GENERAL, SG_ALERT,
+                   "Failed to find route from waypoint " << start << " to "
+                   << end << " at " << parent->getId());
         }
-       FGTaxiRoute empty;
-       return empty;
+        FGTaxiRoute empty;
+        return empty;
         //exit(1); //TODO exit more gracefully, no need to stall the whole sim with broken GN's
     } else {
         // assemble route from backtrace information
         intVec nodes, routes;
-        FGTaxiNodebt = lastNode;
+        FGTaxiNode *bt = lastNode;
         while (bt->getPreviousNode() != 0) {
             nodes.push_back(bt->getIndex());
             routes.push_back(bt->getPreviousSegment()->getIndex());
@@ -441,116 +438,163 @@ FGTaxiRoute FGGroundNetwork::findShortestRoute(int start, int end, bool fullSear
     }
 }
 
-int FGTaxiSegment::getPenalty(int nGates) {
-     int penalty = 0;
-     if (end->getIndex() < nGates) {
-         penalty += 10000;
-     }
-     if (end->getIsOnRunway()) { // For now. In future versions, need to find out whether runway is active.
-         penalty += 1000;
-     }
-     return penalty;
+int FGTaxiSegment::getPenalty(int nGates)
+{
+    int penalty = 0;
+    if (end->getIndex() < nGates) {
+        penalty += 10000;
+    }
+    if (end->getIsOnRunway()) { // For now. In future versions, need to find out whether runway is active.
+        penalty += 1000;
+    }
+    return penalty;
 }
 
 /* ATC Related Functions */
 
-void FGGroundNetwork::announcePosition(int id, FGAIFlightPlan *intendedRoute, int currentPosition,
-                                      double lat, double lon, double heading, 
-                                      double speed, double alt, double radius, int leg,
-                                      FGAIAircraft *aircraft)
+void FGGroundNetwork::announcePosition(int id,
+                                       FGAIFlightPlan * intendedRoute,
+                                       int currentPosition, double lat,
+                                       double lon, double heading,
+                                       double speed, double alt,
+                                       double radius, int leg,
+                                       FGAIAircraft * aircraft)
 {
-   TrafficVectorIterator i = activeTraffic.begin();
-   // Search search if the current id alread has an entry
-   // This might be faster using a map instead of a vector, but let's start by taking a safe route
-   if (activeTraffic.size()) {
-     //while ((i->getId() != id) && i != activeTraffic.end()) {
-     while (i != activeTraffic.end()) {
-       if (i->getId() == id) {
-        break;
-       }
-       i++;
-     }
-   }
-   // Add a new TrafficRecord if no one exsists for this aircraft.
-   if (i == activeTraffic.end() || (activeTraffic.size() == 0)) {
-     FGTrafficRecord rec;
-     rec.setId(id);
-     rec.setPositionAndIntentions(currentPosition, intendedRoute);
-     rec.setPositionAndHeading(lat, lon, heading, speed, alt);
-     rec.setRadius(radius); // only need to do this when creating the record.
-     rec.setAircraft(aircraft);
-     activeTraffic.push_back(rec);
-   } else {
-     i->setPositionAndIntentions(currentPosition, intendedRoute); 
-     i->setPositionAndHeading(lat, lon, heading, speed, alt);
-   }
+    init();
+    TrafficVectorIterator i = activeTraffic.begin();
+    // Search search if the current id alread has an entry
+    // This might be faster using a map instead of a vector, but let's start by taking a safe route
+    if (activeTraffic.size()) {
+        //while ((i->getId() != id) && i != activeTraffic.end()) {
+        while (i != activeTraffic.end()) {
+            if (i->getId() == id) {
+                break;
+            }
+            i++;
+        }
+    }
+    // Add a new TrafficRecord if no one exsists for this aircraft.
+    if (i == activeTraffic.end() || (activeTraffic.size() == 0)) {
+        FGTrafficRecord rec;
+        rec.setId(id);
+        rec.setLeg(leg);
+        rec.setPositionAndIntentions(currentPosition, intendedRoute);
+        rec.setPositionAndHeading(lat, lon, heading, speed, alt);
+        rec.setRadius(radius);  // only need to do this when creating the record.
+        rec.setAircraft(aircraft);
+        activeTraffic.push_back(rec);
+    } else {
+        i->setPositionAndIntentions(currentPosition, intendedRoute);
+        i->setPositionAndHeading(lat, lon, heading, speed, alt);
+    }
 }
 
-void FGGroundNetwork::signOff(int id) {
-  TrafficVectorIterator i = activeTraffic.begin();
-   // Search search if the current id alread has an entry
-   // This might be faster using a map instead of a vector, but let's start by taking a safe route
-   if (activeTraffic.size()) {
-     //while ((i->getId() != id) && i != activeTraffic.end()) {
-     while (i != activeTraffic.end()) {
-       if (i->getId() == id) {
-        break;
-       }
-       i++;
-     }
-   }
-   if (i == activeTraffic.end() || (activeTraffic.size() == 0)) {
-     SG_LOG(SG_GENERAL, SG_ALERT, "AI error: Aircraft without traffic record is signing off");
-   } else {
-       i = activeTraffic.erase(i);
-   }
+void FGGroundNetwork::signOff(int id)
+{
+    TrafficVectorIterator i = activeTraffic.begin();
+    // Search search if the current id alread has an entry
+    // This might be faster using a map instead of a vector, but let's start by taking a safe route
+    if (activeTraffic.size()) {
+        //while ((i->getId() != id) && i != activeTraffic.end()) {
+        while (i != activeTraffic.end()) {
+            if (i->getId() == id) {
+                break;
+            }
+            i++;
+        }
+    }
+    if (i == activeTraffic.end() || (activeTraffic.size() == 0)) {
+        SG_LOG(SG_GENERAL, SG_ALERT,
+               "AI error: Aircraft without traffic record is signing off");
+    } else {
+        i = activeTraffic.erase(i);
+    }
 }
 
-void FGGroundNetwork::update(int id, double lat, double lon, double heading, double speed, double alt, 
-                            double dt) {
-   // Check whether aircraft are on hold due to a preceding pushback. If so, make sure to 
-   // Transmit air-to-ground "Ready to taxi request:
-   // Transmit ground to air approval / hold
-   // Transmit confirmation ... 
-   // Probably use a status mechanism similar to the Engine start procedure in the startup controller.
-
-
-   TrafficVectorIterator i = activeTraffic.begin();
-   // Search search if the current id has an entry
-   // This might be faster using a map instead of a vector, but let's start by taking a safe route
-   TrafficVectorIterator current, closest;
-   if (activeTraffic.size()) {
-     //while ((i->getId() != id) && i != activeTraffic.end()) {
-     while (i != activeTraffic.end()) {
-       if (i->getId() == id) {
-        break;
-       }
-       i++;
-     }
-   }
-   // update position of the current aircraft
-   if (i == activeTraffic.end() || (activeTraffic.size() == 0)) {
-     SG_LOG(SG_GENERAL, SG_ALERT, "AI error: updating aircraft without traffic record");
-   } else {
-     i->setPositionAndHeading(lat, lon, heading, speed, alt);
-     current = i;
-   }
-  
-   setDt(getDt() + dt);
-  
-   // Update every three secs, but add some randomness
-   // to prevent all IA objects doing this in synchrony
-   //if (getDt() < (3.0) + (rand() % 10))
-   //  return;
-   //else
-   //  setDt(0);
-   current->clearResolveCircularWait();
-   current->setWaitsForId(0);
-   checkSpeedAdjustment(id, lat, lon, heading, speed, alt);
-   checkHoldPosition   (id, lat, lon, heading, speed, alt);
-   if (checkForCircularWaits(id)) {
-       i->setResolveCircularWait();
-   }
+void FGGroundNetwork::updateAircraftInformation(int id, double lat, double lon,
+                                                double heading, double speed, double alt,
+                                                double dt)
+{
+    // Check whether aircraft are on hold due to a preceding pushback. If so, make sure to 
+    // Transmit air-to-ground "Ready to taxi request:
+    // Transmit ground to air approval / hold
+    // Transmit confirmation ... 
+    // Probably use a status mechanism similar to the Engine start procedure in the startup controller.
+
+
+    TrafficVectorIterator i = activeTraffic.begin();
+    // Search search if the current id has an entry
+    // This might be faster using a map instead of a vector, but let's start by taking a safe route
+    TrafficVectorIterator current, closest;
+    if (activeTraffic.size()) {
+        //while ((i->getId() != id) && i != activeTraffic.end()) {
+        while (i != activeTraffic.end()) {
+            if (i->getId() == id) {
+                break;
+            }
+            i++;
+        }
+    }
+    // update position of the current aircraft
+    if (i == activeTraffic.end() || (activeTraffic.size() == 0)) {
+        SG_LOG(SG_GENERAL, SG_ALERT,
+               "AI error: updating aircraft without traffic record");
+    } else {
+        i->setPositionAndHeading(lat, lon, heading, speed, alt);
+        current = i;
+    }
+
+    setDt(getDt() + dt);
+
+    // Update every three secs, but add some randomness
+    // to prevent all IA objects doing this in synchrony
+    //if (getDt() < (3.0) + (rand() % 10))
+    //  return;
+    //else
+    //  setDt(0);
+    current->clearResolveCircularWait();
+    current->setWaitsForId(0);
+    checkSpeedAdjustment(id, lat, lon, heading, speed, alt);
+    bool needsTaxiClearance = current->getAircraft()->getTaxiClearanceRequest();
+    if (!needsTaxiClearance) {
+        checkHoldPosition(id, lat, lon, heading, speed, alt);
+        if (checkForCircularWaits(id)) {
+            i->setResolveCircularWait();
+        }
+    } else {
+        current->setHoldPosition(true);
+        int state = current->getState();
+        time_t now = time(NULL) + fgGetLong("/sim/time/warp");
+        if ((now - lastTransmission) > 15) {
+            available = true;
+        }
+        if ((state < 3) && available) {
+             transmit(&(*current), MSG_REQUEST_TAXI_CLEARANCE, ATC_AIR_TO_GROUND);
+             current->setState(3);
+             lastTransmission = now;
+             available = false;
+        }
+        if ((state == 3) && available) {
+            transmit(&(*current), MSG_ISSUE_TAXI_CLEARANCE, ATC_GROUND_TO_AIR);
+            current->setState(4);
+            lastTransmission = now;
+            available = false;
+        }
+        if ((state == 4) && available) {
+            transmit(&(*current), MSG_ACKNOWLEDGE_TAXI_CLEARANCE, ATC_AIR_TO_GROUND);
+            current->setState(5);
+            lastTransmission = now;
+            available = false;
+        }
+        if ((state == 5) && available) {
+            current->setState(0);
+            current->getAircraft()->setTaxiClearanceRequest(false);
+            current->setHoldPosition(true);
+            available = false;
+        }
+
+    }
+
 }
 
 /**
@@ -567,129 +611,123 @@ void FGGroundNetwork::update(int id, double lat, double lon, double heading, dou
    not addressed yet, but should be.
 */
 
-void FGGroundNetwork::checkSpeedAdjustment(int id, double lat, 
-                                          double lon, double heading, 
-                                          double speed, double alt)
+void FGGroundNetwork::checkSpeedAdjustment(int id, double lat,
+                                           double lon, double heading,
+                                           double speed, double alt)
 {
-  
-  TrafficVectorIterator current, closest;
-  TrafficVectorIterator i = activeTraffic.begin();
-  bool otherReasonToSlowDown = false;
-  bool previousInstruction;
-  if (activeTraffic.size()) 
-    {
-      //while ((i->getId() != id) && (i != activeTraffic.end()))
-      while (i != activeTraffic.end()) {
-       if (i->getId() == id) {
-         break;
-       }
-       i++;
-      }
-    }
-  else
-    {
-      return;
-    }
-  if (i == activeTraffic.end() || (activeTraffic.size() == 0)) {
-    SG_LOG(SG_GENERAL, SG_ALERT, "AI error: Trying to access non-existing aircraft in FGGroundNetwork::checkSpeedAdjustment");
-  }
-  current = i;
-  //closest = current;
-  
-  previousInstruction = current->getSpeedAdjustment();
-  double mindist = HUGE_VAL;
-  if (activeTraffic.size()) 
-    {
-      double course, dist, bearing, minbearing, az2;
-      SGGeod curr(SGGeod::fromDegM(lon, lat, alt));
-      //TrafficVector iterator closest;
-      closest = current;
-      for (TrafficVectorIterator i = activeTraffic.begin(); 
-          i != activeTraffic.end(); i++)
-       {
-         if (i == current) {
-        continue;
-      }
-      
-        SGGeod other(SGGeod::fromDegM(i->getLongitude(),
-          i->getLatitude(), i->getAltitude()));
-        SGGeodesy::inverse(curr, other, course, az2, dist);
-        bearing = fabs(heading-course);
-           if (bearing > 180)
-             bearing = 360-bearing;
-           if ((dist < mindist) && (bearing < 60.0))
-             {
-               mindist = dist;
-               closest = i;
-               minbearing = bearing;
-             }
-       }
-      //Check traffic at the tower controller
-      if (towerController->hasActiveTraffic())
-       {
-         for (TrafficVectorIterator i = towerController->getActiveTraffic().begin(); 
-              i != towerController->getActiveTraffic().end(); i++)
-           {
-             //cerr << "Comparing " << current->getId() << " and " << i->getId() << endl;
-             SGGeod other(SGGeod::fromDegM(i->getLongitude(),
-                                            i->getLatitude(), 
-                                            i->getAltitude()));
-        SGGeodesy::inverse(curr, other, course, az2, dist);
-        bearing = fabs(heading-course);
-             if (bearing > 180)
-          bearing = 360-bearing;
-             if ((dist < mindist) && (bearing < 60.0))
-               {
-                 mindist = dist;
-                 closest = i;
-                 minbearing = bearing;
-                 otherReasonToSlowDown = true;
-               }
-           }
-       }
-      // Finally, check UserPosition
-      double userLatitude  = fgGetDouble("/position/latitude-deg");
-      double userLongitude = fgGetDouble("/position/longitude-deg");
-      SGGeod user(SGGeod::fromDeg(userLongitude,userLatitude));
-      SGGeodesy::inverse(curr, user, course, az2, dist);
-
-      bearing = fabs(heading-course);
-      if (bearing > 180)
-      bearing = 360-bearing;
-      if ((dist < mindist) && (bearing < 60.0))
-       {
-         mindist = dist;
-         //closest = i;
-         minbearing = bearing;
-         otherReasonToSlowDown = true;
-       }
-
-      current->clearSpeedAdjustment();
-    
-      if (current->checkPositionAndIntentions(*closest) || otherReasonToSlowDown) 
-       {
-          double maxAllowableDistance = (1.1*current->getRadius()) + (1.1*closest->getRadius());
-          if (mindist < 2*maxAllowableDistance)
-            {
-              if (current->getId() == closest->getWaitsForId())
-                return;
-              else 
-                current->setWaitsForId(closest->getId());
-              if (closest->getId() != current->getId())
-                current->setSpeedAdjustment(closest->getSpeed()* (mindist/100));
-              else
-                current->setSpeedAdjustment(0); // This can only happen when the user aircraft is the one closest
-              if (mindist < maxAllowableDistance)
-                {
-                  //double newSpeed = (maxAllowableDistance-mindist);
-                  //current->setSpeedAdjustment(newSpeed);
-                  //if (mindist < 0.5* maxAllowableDistance)
-                  //  {
-                      current->setSpeedAdjustment(0);
-                      //  }
-                }
-            }
-       }
+
+    TrafficVectorIterator current, closest;
+    TrafficVectorIterator i = activeTraffic.begin();
+    bool otherReasonToSlowDown = false;
+    bool previousInstruction;
+    if (activeTraffic.size()) {
+        //while ((i->getId() != id) && (i != activeTraffic.end()))
+        while (i != activeTraffic.end()) {
+            if (i->getId() == id) {
+                break;
+            }
+            i++;
+        }
+    } else {
+        return;
+    }
+    if (i == activeTraffic.end() || (activeTraffic.size() == 0)) {
+        SG_LOG(SG_GENERAL, SG_ALERT,
+               "AI error: Trying to access non-existing aircraft in FGGroundNetwork::checkSpeedAdjustment");
+    }
+    current = i;
+    //closest = current;
+
+    previousInstruction = current->getSpeedAdjustment();
+    double mindist = HUGE_VAL;
+    if (activeTraffic.size()) {
+        double course, dist, bearing, minbearing, az2;
+        SGGeod curr(SGGeod::fromDegM(lon, lat, alt));
+        //TrafficVector iterator closest;
+        closest = current;
+        for (TrafficVectorIterator i = activeTraffic.begin();
+             i != activeTraffic.end(); i++) {
+            if (i == current) {
+                continue;
+            }
+
+            SGGeod other(SGGeod::fromDegM(i->getLongitude(),
+                                          i->getLatitude(),
+                                          i->getAltitude()));
+            SGGeodesy::inverse(curr, other, course, az2, dist);
+            bearing = fabs(heading - course);
+            if (bearing > 180)
+                bearing = 360 - bearing;
+            if ((dist < mindist) && (bearing < 60.0)) {
+                mindist = dist;
+                closest = i;
+                minbearing = bearing;
+            }
+        }
+        //Check traffic at the tower controller
+        if (towerController->hasActiveTraffic()) {
+            for (TrafficVectorIterator i =
+                 towerController->getActiveTraffic().begin();
+                 i != towerController->getActiveTraffic().end(); i++) {
+                //cerr << "Comparing " << current->getId() << " and " << i->getId() << endl;
+                SGGeod other(SGGeod::fromDegM(i->getLongitude(),
+                                              i->getLatitude(),
+                                              i->getAltitude()));
+                SGGeodesy::inverse(curr, other, course, az2, dist);
+                bearing = fabs(heading - course);
+                if (bearing > 180)
+                    bearing = 360 - bearing;
+                if ((dist < mindist) && (bearing < 60.0)) {
+                    mindist = dist;
+                    closest = i;
+                    minbearing = bearing;
+                    otherReasonToSlowDown = true;
+                }
+            }
+        }
+        // Finally, check UserPosition
+        double userLatitude = fgGetDouble("/position/latitude-deg");
+        double userLongitude = fgGetDouble("/position/longitude-deg");
+        SGGeod user(SGGeod::fromDeg(userLongitude, userLatitude));
+        SGGeodesy::inverse(curr, user, course, az2, dist);
+
+        bearing = fabs(heading - course);
+        if (bearing > 180)
+            bearing = 360 - bearing;
+        if ((dist < mindist) && (bearing < 60.0)) {
+            mindist = dist;
+            //closest = i;
+            minbearing = bearing;
+            otherReasonToSlowDown = true;
+        }
+
+        current->clearSpeedAdjustment();
+
+        if (current->checkPositionAndIntentions(*closest)
+            || otherReasonToSlowDown) {
+            double maxAllowableDistance =
+                (1.1 * current->getRadius()) +
+                (1.1 * closest->getRadius());
+            if (mindist < 2 * maxAllowableDistance) {
+                if (current->getId() == closest->getWaitsForId())
+                    return;
+                else
+                    current->setWaitsForId(closest->getId());
+                if (closest->getId() != current->getId())
+                    current->setSpeedAdjustment(closest->getSpeed() *
+                                                (mindist / 100));
+                else
+                    current->setSpeedAdjustment(0);     // This can only happen when the user aircraft is the one closest
+                if (mindist < maxAllowableDistance) {
+                    //double newSpeed = (maxAllowableDistance-mindist);
+                    //current->setSpeedAdjustment(newSpeed);
+                    //if (mindist < 0.5* maxAllowableDistance)
+                    //  {
+                    current->setSpeedAdjustment(0);
+                    //  }
+                }
+            }
+        }
     }
 }
 
@@ -701,114 +739,146 @@ void FGGroundNetwork::checkSpeedAdjustment(int id, double lat,
    3) For crossing or merging taxiroutes.
 */
 
-void FGGroundNetwork::checkHoldPosition(int id, double lat, 
-                                       double lon, double heading, 
-                                       double speed, double alt)
+void FGGroundNetwork::checkHoldPosition(int id, double lat,
+                                        double lon, double heading,
+                                        double speed, double alt)
 {
-  
-  TrafficVectorIterator current;
-  TrafficVectorIterator i = activeTraffic.begin();
-  if (activeTraffic.size()) 
-    {
-      //while ((i->getId() != id) && i != activeTraffic.end()) 
-      while (i != activeTraffic.end()) {
-       if (i->getId() == id) {
-         break;
-       }
-       i++;
-      }
-    }
-  else
-    {
-      return ;
-    } 
-  if (i == activeTraffic.end() || (activeTraffic.size() == 0)) {
-    SG_LOG(SG_GENERAL, SG_ALERT, "AI error: Trying to access non-existing aircraft in FGGroundNetwork::checkHoldPosition");
-  }
-  current = i;
-  current->setHoldPosition(false);
-  SGGeod curr(SGGeod::fromDegM(lon, lat, alt));
-  
-  for (i = activeTraffic.begin(); 
-       i != activeTraffic.end(); i++)
-    {
-      if (i->getId() != current->getId()) 
-       {
-         int node = current->crosses(this, *i);
-         if (node != -1)
-           {
-          FGTaxiNode* taxiNode = findNode(node);
-          
-             // Determine whether it's save to continue or not. 
-             // If we have a crossing route, there are two possibilities:
-             // 1) This is an interestion
-             // 2) This is oncoming two-way traffic, using the same taxiway.
-             //cerr << "Hold check 1 : " << id << " has common node " << node << endl;
-            
-        SGGeod other(SGGeod::fromDegM(i->getLongitude(), i->getLatitude(), i->getAltitude()));
-        bool needsToWait;
-             bool opposing;
-             if (current->isOpposing(this, *i, node))
-               {
-                 needsToWait = true;
-                 opposing    = true;
-                 //cerr << "Hold check 2 : " << node << "  has opposing segment " << endl;
-                 // issue a "Hold Position" as soon as we're close to the offending node
-                 // For now, I'm doing this as long as the other aircraft doesn't
-                 // have a hold instruction as soon as we're within a reasonable 
-                 // distance from the offending node.
-                 // This may be a bit of a conservative estimate though, as it may
-                 // be well possible that both aircraft can both continue to taxi 
-                 // without crashing into each other.
-               } 
-             else 
-               {
-                 opposing = false;
-                 if (SGGeodesy::distanceM(other, taxiNode->getGeod()) > 200) // 2.0*i->getRadius())
-                   {
-                     needsToWait = false; 
-                     //cerr << "Hold check 3 : " << id <<"  Other aircraft approaching node is still far away. (" << dist << " nm). Can safely continue " 
-                     //           << endl;
-                   }
-                 else 
-                   {
-                     needsToWait = true;
-                     //cerr << "Hold check 4: " << id << "  Would need to wait for other aircraft : distance = " << dist << " meters" << endl;
-                   }
-               }
-      
-      double dist = SGGeodesy::distanceM(curr, taxiNode->getGeod());
-      if (!(i->hasHoldPosition()))
-               {
-                 
-                 if ((dist < 200) && //2.5*current->getRadius()) && 
-                     (needsToWait) &&
-                     (i->onRoute(this, *current)) &&
-                     //((i->onRoute(this, *current)) || ((!(i->getSpeedAdjustment())))) &&
-                     (!(current->getId() == i->getWaitsForId())))
-                     //(!(i->getSpeedAdjustment()))) // &&
-                     //(!(current->getSpeedAdjustment())))
-                   
-                   {
-                     current->setHoldPosition(true);
-                     current->setWaitsForId(i->getId());
-                     //cerr << "Hold check 5: " << current->getCallSign() <<"  Setting Hold Position: distance to node ("  << node << ") "
-                     //           << dist << " meters. Waiting for " << i->getCallSign();
-                     //if (opposing)
-                     //cerr <<" [opposing] " << endl;
-                     //else
-                     //        cerr << "[non-opposing] " << endl;
-                     //if (i->hasSpeefAdjustment())
-                     //        {
-                     //          cerr << " (which in turn waits for ) " << i->
-                   }
-                 else
-                   {
-                     //cerr << "Hold check 6: " << id << "  No need to hold yet: Distance to node : " << dist << " nm"<< endl;
-                   }
-               }
-           }
-       }
+    TrafficVectorIterator current;
+    TrafficVectorIterator i = activeTraffic.begin();
+    if (activeTraffic.size()) {
+        //while ((i->getId() != id) && i != activeTraffic.end()) 
+        while (i != activeTraffic.end()) {
+            if (i->getId() == id) {
+                break;
+            }
+            i++;
+        }
+    } else {
+        return;
+    }
+    if (i == activeTraffic.end() || (activeTraffic.size() == 0)) {
+        SG_LOG(SG_GENERAL, SG_ALERT,
+               "AI error: Trying to access non-existing aircraft in FGGroundNetwork::checkHoldPosition");
+    }
+    current = i;
+    bool origStatus = current->hasHoldPosition();
+    current->setHoldPosition(false);
+    SGGeod curr(SGGeod::fromDegM(lon, lat, alt));
+
+    for (i = activeTraffic.begin(); i != activeTraffic.end(); i++) {
+        if (i->getId() != current->getId()) {
+            int node = current->crosses(this, *i);
+            if (node != -1) {
+                FGTaxiNode *taxiNode = findNode(node);
+
+                // Determine whether it's save to continue or not. 
+                // If we have a crossing route, there are two possibilities:
+                // 1) This is an interestion
+                // 2) This is oncoming two-way traffic, using the same taxiway.
+                //cerr << "Hold check 1 : " << id << " has common node " << node << endl;
+
+                SGGeod other(SGGeod::
+                             fromDegM(i->getLongitude(), i->getLatitude(),
+                                      i->getAltitude()));
+                bool needsToWait;
+                bool opposing;
+                if (current->isOpposing(this, *i, node)) {
+                    needsToWait = true;
+                    opposing = true;
+                    //cerr << "Hold check 2 : " << node << "  has opposing segment " << endl;
+                    // issue a "Hold Position" as soon as we're close to the offending node
+                    // For now, I'm doing this as long as the other aircraft doesn't
+                    // have a hold instruction as soon as we're within a reasonable 
+                    // distance from the offending node.
+                    // This may be a bit of a conservative estimate though, as it may
+                    // be well possible that both aircraft can both continue to taxi 
+                    // without crashing into each other.
+                } else {
+                    opposing = false;
+                    if (SGGeodesy::distanceM(other, taxiNode->getGeod()) > 200) // 2.0*i->getRadius())
+                    {
+                        needsToWait = false;
+                        //cerr << "Hold check 3 : " << id <<"  Other aircraft approaching node is still far away. (" << dist << " nm). Can safely continue " 
+                        //           << endl;
+                    } else {
+                        needsToWait = true;
+                        //cerr << "Hold check 4: " << id << "  Would need to wait for other aircraft : distance = " << dist << " meters" << endl;
+                    }
+                }
+
+                double dist =
+                    SGGeodesy::distanceM(curr, taxiNode->getGeod());
+                if (!(i->hasHoldPosition())) {
+
+                    if ((dist < 200) && //2.5*current->getRadius()) && 
+                        (needsToWait) && (i->onRoute(this, *current)) &&
+                        //((i->onRoute(this, *current)) || ((!(i->getSpeedAdjustment())))) &&
+                        (!(current->getId() == i->getWaitsForId())))
+                        //(!(i->getSpeedAdjustment()))) // &&
+                        //(!(current->getSpeedAdjustment())))
+
+                    {
+                        current->setHoldPosition(true);
+                        current->setWaitsForId(i->getId());
+                        //cerr << "Hold check 5: " << current->getCallSign() <<"  Setting Hold Position: distance to node ("  << node << ") "
+                        //           << dist << " meters. Waiting for " << i->getCallSign();
+                        //if (opposing)
+                        //cerr <<" [opposing] " << endl;
+                        //else
+                        //        cerr << "[non-opposing] " << endl;
+                        //if (i->hasSpeefAdjustment())
+                        //        {
+                        //          cerr << " (which in turn waits for ) " << i->
+                    } else {
+                        //cerr << "Hold check 6: " << id << "  No need to hold yet: Distance to node : " << dist << " nm"<< endl;
+                    }
+                }
+            }
+        }
+    }
+    bool currStatus = current->hasHoldPosition();
+
+    // Either a Hold Position or a resume taxi transmission has been issued
+    time_t now = time(NULL) + fgGetLong("/sim/time/warp");
+    if ((now - lastTransmission) > 2) {
+        available = true;
+    }
+    if ((origStatus != currStatus) && available) {
+        //cerr << "Issueing hold short instrudtion " << currStatus << " " << available << endl;
+        if (currStatus == true) { // No has a hold short instruction
+           transmit(&(*current), MSG_HOLD_POSITION, ATC_GROUND_TO_AIR);
+           //cerr << "Transmittin hold short instrudtion " << currStatus << " " << available << endl;
+           current->setState(1);
+        } else {
+           transmit(&(*current), MSG_RESUME_TAXI, ATC_GROUND_TO_AIR);
+           //cerr << "Transmittig resume instrudtion " << currStatus << " " << available << endl;
+           current->setState(2);
+        }
+        lastTransmission = now;
+        available = false;
+        // Don't act on the changed instruction until the transmission is confirmed
+        // So set back to original status
+        current->setHoldPosition(origStatus);
+        //cerr << "Current state " << current->getState() << endl;
+    } else {
+    }
+    int state = current->getState();
+    if ((state == 1) && (available)) {
+        //cerr << "ACKNOWLEDGE HOLD" << endl;
+        transmit(&(*current), MSG_ACKNOWLEDGE_HOLD_POSITION, ATC_AIR_TO_GROUND);
+        current->setState(0);
+        current->setHoldPosition(true);
+        lastTransmission = now;
+        available = false;
+
+    }
+    if ((state == 2) && (available)) {
+        //cerr << "ACKNOWLEDGE RESUME" << endl;
+        transmit(&(*current), MSG_ACKNOWLEDGE_RESUME_TAXI, ATC_AIR_TO_GROUND);
+        current->setState(0);
+        current->setHoldPosition(false);
+        lastTransmission = now;
+        available = false;
     }
 }
 
@@ -827,142 +897,142 @@ void FGGroundNetwork::checkHoldPosition(int id, double lat,
  */
 
 bool FGGroundNetwork::checkForCircularWaits(int id)
-{  
-   //cerr << "Performing Wait check " << id << endl;
-   int target = 0;
-   TrafficVectorIterator current, other;
-   TrafficVectorIterator i = activeTraffic.begin();
-   int trafficSize = activeTraffic.size();
-   if (trafficSize)  {
+{
+    //cerr << "Performing Wait check " << id << endl;
+    int target = 0;
+    TrafficVectorIterator current, other;
+    TrafficVectorIterator i = activeTraffic.begin();
+    int trafficSize = activeTraffic.size();
+    if (trafficSize) {
         while (i != activeTraffic.end()) {
-        if (i->getId() == id) {
-           break;
-       }
-       i++;
-    }
-  }
-  else {
-      return false;
-  }
-  if (i == activeTraffic.end() || (trafficSize == 0)) {
-    SG_LOG(SG_GENERAL, SG_ALERT, "AI error: Trying to access non-existing aircraft in FGGroundNetwork::checkForCircularWaits");
-  }
-   
-   current = i;
-   target = current->getWaitsForId();
-   //bool printed = false; // Note that this variable is for debugging purposes only.
-   int counter = 0;
-
-   if (id == target) {
-       //cerr << "aircraft waits for user" << endl;
-       return false;
-   }
-
-
-   while ((target > 0) && (target != id) && counter++ < trafficSize) {
-    //printed = true;
-     TrafficVectorIterator i = activeTraffic.begin();
-     if (trafficSize)  {
-          //while ((i->getId() != id) && i != activeTraffic.end()) 
-          while (i != activeTraffic.end()) {
-          if (i->getId() == target) {
-             break;
-         }
-         i++;
-        }
-      }
-      else {
+            if (i->getId() == id) {
+                break;
+            }
+            i++;
+        }
+    } else {
         return false;
-    } 
+    }
     if (i == activeTraffic.end() || (trafficSize == 0)) {
-       //cerr << "[Waiting for traffic at Runway: DONE] " << endl << endl;;
-      // The target id is not found on the current network, which means it's at the tower
-      //SG_LOG(SG_GENERAL, SG_ALERT, "AI error: Trying to access non-existing aircraft in FGGroundNetwork::checkForCircularWaits");
-      return false;
-    }
-    other = i;
-    target = other->getWaitsForId();
-
-    // actually this trap isn't as impossible as it first seemed:
-    // the setWaitsForID(id) is set to current when the aircraft
-    // is waiting for the user controlled aircraft. 
-    //if (current->getId() == other->getId()) {
-    //    cerr << "Caught the impossible trap" << endl;
-    //    cerr << "Current = " << current->getId() << endl;
-    //    cerr << "Other   = " << other  ->getId() << endl;
-    //    for (TrafficVectorIterator at = activeTraffic.begin();
-    //          at != activeTraffic.end();
-    //          at++) {
-    //        cerr << "currently active aircraft : " << at->getCallSign() << " with Id " << at->getId() << " waits for " << at->getWaitsForId() << endl;
-    //    }
-    //    exit(1);
-    if (current->getId() == other->getId())
-       return false;
-    //}
-    //cerr << current->getCallSign() << " (" << current->getId()  << ") " << " -> " << other->getCallSign() 
-    //     << " (" << other->getId()  << "); " << endl;;
-    //current = other;
-   }
+        SG_LOG(SG_GENERAL, SG_ALERT,
+               "AI error: Trying to access non-existing aircraft in FGGroundNetwork::checkForCircularWaits");
+    }
+
+    current = i;
+    target = current->getWaitsForId();
+    //bool printed = false; // Note that this variable is for debugging purposes only.
+    int counter = 0;
 
+    if (id == target) {
+        //cerr << "aircraft waits for user" << endl;
+        return false;
+    }
+
+
+    while ((target > 0) && (target != id) && counter++ < trafficSize) {
+        //printed = true;
+        TrafficVectorIterator i = activeTraffic.begin();
+        if (trafficSize) {
+            //while ((i->getId() != id) && i != activeTraffic.end()) 
+            while (i != activeTraffic.end()) {
+                if (i->getId() == target) {
+                    break;
+                }
+                i++;
+            }
+        } else {
+            return false;
+        }
+        if (i == activeTraffic.end() || (trafficSize == 0)) {
+            //cerr << "[Waiting for traffic at Runway: DONE] " << endl << endl;;
+            // The target id is not found on the current network, which means it's at the tower
+            //SG_LOG(SG_GENERAL, SG_ALERT, "AI error: Trying to access non-existing aircraft in FGGroundNetwork::checkForCircularWaits");
+            return false;
+        }
+        other = i;
+        target = other->getWaitsForId();
+
+        // actually this trap isn't as impossible as it first seemed:
+        // the setWaitsForID(id) is set to current when the aircraft
+        // is waiting for the user controlled aircraft. 
+        //if (current->getId() == other->getId()) {
+        //    cerr << "Caught the impossible trap" << endl;
+        //    cerr << "Current = " << current->getId() << endl;
+        //    cerr << "Other   = " << other  ->getId() << endl;
+        //    for (TrafficVectorIterator at = activeTraffic.begin();
+        //          at != activeTraffic.end();
+        //          at++) {
+        //        cerr << "currently active aircraft : " << at->getCallSign() << " with Id " << at->getId() << " waits for " << at->getWaitsForId() << endl;
+        //    }
+        //    exit(1);
+        if (current->getId() == other->getId())
+            return false;
+        //}
+        //cerr << current->getCallSign() << " (" << current->getId()  << ") " << " -> " << other->getCallSign() 
+        //     << " (" << other->getId()  << "); " << endl;;
+        //current = other;
+    }
 
 
 
 
 
-   //if (printed)
-   //   cerr << "[done] " << endl << endl;;
-   if (id == target) {
-       SG_LOG(SG_GENERAL, SG_WARN, "Detected circular wait condition: Id = " << id << "target = " << target);
-       return true;
-   } else {
-   return false;
-   }
+
+    //if (printed)
+    //   cerr << "[done] " << endl << endl;;
+    if (id == target) {
+        SG_LOG(SG_GENERAL, SG_WARN,
+               "Detected circular wait condition: Id = " << id <<
+               "target = " << target);
+        return true;
+    } else {
+        return false;
+    }
 }
 
 // Note that this function is probably obsolete...
 bool FGGroundNetwork::hasInstruction(int id)
 {
     TrafficVectorIterator i = activeTraffic.begin();
-   // Search search if the current id has an entry
-   // This might be faster using a map instead of a vector, but let's start by taking a safe route
-   if (activeTraffic.size()) 
-     {
-       //while ((i->getId() != id) && i != activeTraffic.end()) {
-       while (i != activeTraffic.end()) {
-        if (i->getId() == id) {
-          break;
-        }
-        i++;
-       }
-     }
-   if (i == activeTraffic.end() || (activeTraffic.size() == 0)) {
-     SG_LOG(SG_GENERAL, SG_ALERT, "AI error: checking ATC instruction for aircraft without traffic record");
-   } else {
-     return i->hasInstruction();
-   }
-  return false;
+    // Search search if the current id has an entry
+    // This might be faster using a map instead of a vector, but let's start by taking a safe route
+    if (activeTraffic.size()) {
+        //while ((i->getId() != id) && i != activeTraffic.end()) {
+        while (i != activeTraffic.end()) {
+            if (i->getId() == id) {
+                break;
+            }
+            i++;
+        }
+    }
+    if (i == activeTraffic.end() || (activeTraffic.size() == 0)) {
+        SG_LOG(SG_GENERAL, SG_ALERT,
+               "AI error: checking ATC instruction for aircraft without traffic record");
+    } else {
+        return i->hasInstruction();
+    }
+    return false;
 }
 
 FGATCInstruction FGGroundNetwork::getInstruction(int id)
 {
-  TrafficVectorIterator i = activeTraffic.begin();
-  // Search search if the current id has an entry
-   // This might be faster using a map instead of a vector, but let's start by taking a safe route
-   if (activeTraffic.size()) {
-     //while ((i->getId() != id) && i != activeTraffic.end()) {
-     while (i != activeTraffic.end()) {
-       if (i->getId() == id) {
-        break;
-       }
-       i++;
-     }
-   }
-   if (i == activeTraffic.end() || (activeTraffic.size() == 0)) {
-     SG_LOG(SG_GENERAL, SG_ALERT, "AI error: requesting ATC instruction for aircraft without traffic record");
-   } else {
-     return i->getInstruction();
-   }
-  return FGATCInstruction();
+    TrafficVectorIterator i = activeTraffic.begin();
+    // Search search if the current id has an entry
+    // This might be faster using a map instead of a vector, but let's start by taking a safe route
+    if (activeTraffic.size()) {
+        //while ((i->getId() != id) && i != activeTraffic.end()) {
+        while (i != activeTraffic.end()) {
+            if (i->getId() == id) {
+                break;
+            }
+            i++;
+        }
+    }
+    if (i == activeTraffic.end() || (activeTraffic.size() == 0)) {
+        SG_LOG(SG_GENERAL, SG_ALERT,
+               "AI error: requesting ATC instruction for aircraft without traffic record");
+    } else {
+        return i->getInstruction();
+    }
+    return FGATCInstruction();
 }
-
-