src/ATC/ground.cxx

   1 // FGGround - a class to provide ground control at larger airports.
   2 //
   3 // Written by David Luff, started March 2002.
   4 //
   5 // Copyright (C) 2002  David C. Luff - david.luff@nottingham.ac.uk
   6 //
   7 // This program is free software; you can redistribute it and/or
   8 // modify it under the terms of the GNU General Public License as
   9 // published by the Free Software Foundation; either version 2 of the
  10 // License, or (at your option) any later version.
  11 //
  12 // This program is distributed in the hope that it will be useful, but
  13 // WITHOUT ANY WARRANTY; without even the implied warranty of
  14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15 // General Public License for more details.
  16 //
  17 // You should have received a copy of the GNU General Public License
  18 // along with this program; if not, write to the Free Software
  19 // Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20
  21 #include <simgear/misc/sg_path.hxx>
  22 #include <simgear/math/sg_random.h>
  23 #include <simgear/debug/logstream.hxx>
  24 #include <simgear/misc/sgstream.hxx>
  25 #include <simgear/constants.h>
  26 #include <Main/globals.hxx>
  27
  28 #include <stdlib.h>
  29 #include STL_FSTREAM
  30
  31 #include "ground.hxx"
  32 #include "ATCutils.hxx"
  33
  34 SG_USING_STD(ifstream);
  35 SG_USING_STD(cout);
  36
  37 node::node() {
  38 }
  39
  40 node::~node() {
  41         for(unsigned int i=0; i < arcs.size(); ++i) {
  42                 delete arcs[i];
  43         }
  44 }
  45
  46 // Make sure that a_path.cost += distance is safe from the moment it's created.
  47 a_path::a_path() {
  48         cost = 0;
  49 }
  50
  51 FGGround::FGGround() {
  52         display = false;
  53         networkLoadOK = false;
  54 }
  55
  56 FGGround::~FGGround() {
  57 }
  58
  59 void FGGround::ParseRwyExits(node* np, char* es) {
  60         char* token;
  61         char estr[20];
  62         strcpy(estr, es);
  63         const char delimiters[] = "-";
  64         token = strtok(estr, delimiters);
  65         while(token != NULL) {
  66                 int i = atoi(token);
  67                 //cout << "token = " << token << endl;
  68                 //cout << "rwy number = " << i << endl;
  69                 //runways[(atoi(token))].exits.push_back(np);
  70                 runways[i].exits.push_back(np);
  71                 //cout << "token = " << token << '\n';
  72                 token = strtok(NULL, delimiters);
  73         }
  74 }
  75
  76
  77 // Load the ground logical network of the current instances airport
  78 // Return true if successfull.
  79 // TODO - currently the file is assumed to reside in the base/ATC directory.
  80 // This might change to something more thought out in the future.
  81 // NOTE - currently it is assumed that all nodes are loaded before any arcs.
  82 // It won't work ATM if this doesn't hold true.
  83 bool FGGround::LoadNetwork() {
  84         node* np;
  85         arc* ap;
  86         Gate* gp;
  87
  88         int gateCount = 0;      // This is used to allocate gateID's from zero upwards
  89         // This may well change in the future - probably to reading in the real-world
  90         // gate numbers from file.
  91
  92         ifstream fin;
  93         SGPath path = globals->get_fg_root();
  94         //string taxiPath = "ATC/" + ident + ".taxi";
  95         string taxiPath = "ATC/KEMT.taxi";      // FIXME - HARDWIRED FOR TESTING
  96         path.append(taxiPath);
  97
  98         SG_LOG(SG_GENERAL, SG_INFO, "Trying to read taxiway data for " << ident << "...");
  99         //cout << "Trying to read taxiway data for " << ident << "..." << endl;
 100         fin.open(path.c_str(), ios::in);
 101         if(!fin) {
 102                 SG_LOG(SG_GENERAL, SG_ALERT, "Unable to open taxiway data input file " << path.c_str());
 103                 //cout << "Unable to open taxiway data input file " << path.c_str() << endl;
 104                 return(false);
 105         }
 106
 107         char ch;
 108         char buf[30];
 109         while(!fin.eof()) {
 110                 fin >> buf;
 111                 // Node, arc, or [End]?
 112                 //cout << "Read in ground network element type = " << buf << endl;
 113                 if(!strcmp(buf, "[End]")) {             // TODO - maybe make this more robust to spelling errors by just looking for '['
 114                         SG_LOG(SG_GENERAL, SG_INFO, "Done reading " << path.c_str() << endl);
 115                         break;
 116                 } else if(!strcmp(buf, "N")) {
 117                         // Node
 118                         np = new node;
 119                         np->struct_type = NODE;
 120                         fin >> buf;
 121                         np->nodeID = atoi(buf);
 122                         fin >> buf;
 123                         np->pos.setlon(atof(buf));
 124                         fin >> buf;
 125                         np->pos.setlat(atof(buf));
 126                         fin >> buf;
 127                         np->pos.setelev(atof(buf));
 128                         fin >> buf;             // node type
 129                         if(!strcmp(buf, "J")) {
 130                                 np->type = JUNCTION;
 131                         } else if(!strcmp(buf, "T")) {
 132                                 np->type = TJUNCTION;
 133                         } else if(!strcmp(buf, "H")) {
 134                                 np->type = HOLD;
 135                         } else {
 136                                 SG_LOG(SG_GENERAL, SG_ALERT, "**** ERROR ***** Unknown node type in taxi network...\n");
 137                                 delete np;
 138                                 return(false);
 139                         }
 140                         fin >> buf;             // rwy exit information - gets parsed later - FRAGILE - will break if buf is reused.
 141                         // Now the name
 142                         fin >> ch;      // strip the leading " off
 143                         np->name = "";
 144                         while(1) {
 145                                 fin.unsetf(ios::skipws);
 146                                 fin >> ch;
 147                                 if((ch == '"') || (ch == 0x0A)) {
 148                                         break;
 149                                 }   // we shouldn't need the 0x0A but it makes a nice safely in case someone leaves off the "
 150                                 np->name += ch;
 151                         }
 152                         fin.setf(ios::skipws);
 153                         network.push_back(np);
 154                         // FIXME - fragile - replies on buf not getting modified from exits read to here
 155                         // see if we also need to push it onto the runway exit list
 156                         //cout << "strlen(buf) = " << strlen(buf) << endl;
 157                         if(strlen(buf) > 2) {
 158                                 //cout << "Calling ParseRwyExits for " << buf << endl;
 159                                 ParseRwyExits(np, buf);
 160                         }
 161                 } else if(!strcmp(buf, "A")) {
 162                         ap = new arc;
 163                         ap->struct_type = ARC;
 164                         fin >> buf;
 165                         ap->n1 = atoi(buf);
 166                         fin >> buf;
 167                         ap->n2 = atoi(buf);
 168                         fin >> buf;
 169                         if(!strcmp(buf, "R")) {
 170                                 ap->type = RUNWAY;
 171                         } else if(!strcmp(buf, "T")) {
 172                                 ap->type = TAXIWAY;
 173                         } else {
 174                                 SG_LOG(SG_GENERAL, SG_ALERT, "**** ERROR ***** Unknown arc type in taxi network...\n");
 175                                 delete ap;
 176                                 return(false);
 177                         }
 178                         // directed?
 179                         fin >> buf;
 180                         if(!strcmp(buf, "Y")) {
 181                                 ap->directed = true;
 182                         } else if(!strcmp(buf, "N")) {
 183                                 ap->directed = false;
 184                         } else {
 185                                 SG_LOG(SG_GENERAL, SG_ALERT, "**** ERROR ***** Unknown arc directed value in taxi network - should be Y/N !!!\n");
 186                                 delete ap;
 187                                 return(false);
 188                         }
 189                         // Now the name
 190                         ap->name = "";
 191                         while(1) {
 192                                 fin.unsetf(ios::skipws);
 193                                 fin >> ch;
 194                                 ap->name += ch;
 195                                 if((ch == '"') || (ch == 0x0A)) {
 196                                         break;
 197                                 }   // we shouldn't need the 0x0A but it makes a nice safely in case someone leaves off the "
 198                         }
 199                         fin.setf(ios::skipws);
 200                         ap->distance = (int)dclGetHorizontalSeparation(network[ap->n1]->pos, network[ap->n2]->pos);
 201                         //cout << "Distance  = " << ap->distance << '\n';
 202                         network[ap->n1]->arcs.push_back(ap);
 203                         network[ap->n2]->arcs.push_back(ap);
 204                 } else if(!strcmp(buf, "G")) {
 205                         gp = new Gate;
 206                         gp->struct_type = NODE;
 207                         gp->type = GATE;
 208                         fin >> buf;
 209                         gp->nodeID = atoi(buf);
 210                         fin >> buf;
 211                         gp->pos.setlon(atof(buf));
 212                         fin >> buf;
 213                         gp->pos.setlat(atof(buf));
 214                         fin >> buf;
 215                         gp->pos.setelev(atof(buf));
 216                         fin >> buf;             // gate type - ignore this for now
 217                         fin >> buf;             // gate heading
 218                         gp->heading = atoi(buf);
 219                         // Now the name
 220                         gp->name = "";
 221                         while(1) {
 222                                 fin.unsetf(ios::skipws);
 223                                 fin >> ch;
 224                                 gp->name += ch;
 225                                 if((ch == '"') || (ch == 0x0A)) {
 226                                         break;
 227                                 }   // we shouldn't need the 0x0A but it makes a nice safely in case someone leaves off the "
 228                         }
 229                         fin.setf(ios::skipws);
 230                         gp->id = gateCount;             // Warning - this will likely change in the future.
 231                         gp->used = false;
 232                         network.push_back(gp);
 233                         gates[gateCount] = gp;
 234                         gateCount++;
 235                 } else {
 236                         // Something has gone seriously pear-shaped
 237                         SG_LOG(SG_GENERAL, SG_ALERT, "********* ERROR - unknown ground network element type... aborting read of " << path.c_str() << '\n');
 238                         return(false);
 239                 }
 240
 241                 fin >> skipeol;
 242         }
 243         return(true);
 244 }
 245
 246 void FGGround::Init() {
 247         display = false;
 248
 249         // For now we'll hardwire the threshold end
 250         Point3D P010(-118.037483, 34.081358, 296 * SG_FEET_TO_METER);
 251         double hdg = 25.32;
 252         ortho.Init(P010, hdg);
 253
 254         networkLoadOK = LoadNetwork();
 255 }
 256
 257 void FGGround::Update() {
 258         // Each time step, what do we need to do?
 259         // We need to go through the list of outstanding requests and acknowedgements
 260         // and process at least one of them.
 261         // We need to go through the list of planes under our control and check if
 262         // any need to be addressed.
 263         // We need to check for planes not under our control coming within our
 264         // control area and address if necessary.
 265
 266         // Lets take the example of a plane which has just contacted ground
 267         // following landing - presumably requesting where to go?
 268         // First we need to establish the position of the plane within the logical network.
 269         // Next we need to decide where its going.
 270 }
 271
 272 // Return a random gate ID of an unused gate.
 273 // Two error values may be returned and must be checked for by the calling function:
 274 // -2 signifies that no gates exist at this airport.
 275 // -1 signifies that all gates are currently full.
 276 int FGGround::GetRandomGateID() {
 277         // Check that this airport actually has some gates!!
 278         if(!gates.size()) {
 279                 return(-2);
 280         }
 281
 282         gate_vec_type gateVec;
 283         int num = 0;
 284         int thenum;
 285         int ID;
 286
 287         gatesItr = gates.begin();
 288         while(gatesItr != gates.end()) {
 289                 if((gatesItr->second)->used == false) {
 290                         gateVec.push_back(gatesItr->second);
 291                         num++;
 292                 }
 293                 ++gatesItr;
 294         }
 295
 296         // Check that there are some unused gates!
 297         if(!gateVec.size()) {
 298                 return(-1);
 299         }
 300
 301         // Randomly select one from the list
 302         sg_srandom_time();
 303         thenum = (int)(sg_random() * gateVec.size());
 304         ID = gateVec[thenum]->id;
 305
 306         return(ID);
 307 }
 308
 309 // Return a pointer to an unused gate node
 310 Gate* FGGround::GetGateNode() {
 311         int id = GetRandomGateID();
 312         if(id < 0) {
 313                 return(NULL);
 314         } else {
 315                 return(gates[id]);
 316         }
 317 }
 318
 319
 320 // WARNING - This is hardwired to my prototype logical network format
 321 // and will almost certainly change when Bernie's stuff comes on-line.
 322 node* FGGround::GetThresholdNode(string rwyID) {
 323         // For now go through all the nodes and parse their names
 324         // Maybe in the future we'll map threshold nodes by ID
 325         //cout << "Size of network is " << network.size() << '\n';
 326         for(unsigned int i=0; i<network.size(); ++i) {
 327                 //cout << "Name = " << network[i]->name << '\n';
 328                 if(network[i]->name.size()) {
 329                         string s = network[i]->name;
 330                         // Warning - the next bit is fragile and dependent on my current naming scheme
 331                         //cout << "substr = " << s.substr(0,3) << '\n';
 332                         //cout << "size of s = " << s.size() << '\n';
 333                         if(s.substr(0,3) == "rwy") {
 334                                 //cout << "subsubstr = " << s.substr(4, s.size() - 4) << '\n';
 335                                 if(s.substr(4, s.size() - 4) == rwyID) {
 336                                         return network[i];
 337                                 }
 338                         }
 339                 }
 340         }
 341         return NULL;
 342 }
 343
 344 // Get a path from a point on a runway to a gate
 345 // TODO !!
 346
 347 // Get a path from a node to another node
 348 // Eventually we will need complex algorithms for this taking other traffic,
 349 // shortest path and suitable paths into accout.
 350 // For now we'll just call the shortest path algorithm.
 351 ground_network_path_type FGGround::GetPath(node* A, node* B) {
 352         return(GetShortestPath(A, B));
 353 };
 354
 355 // Get a path from a node to a runway threshold
 356 ground_network_path_type FGGround::GetPath(node* A, string rwyID) {
 357         node* b = GetThresholdNode(rwyID);
 358         if(b == NULL) {
 359                 SG_LOG(SG_GENERAL, SG_ALERT, "ERROR - unable to find path to runway theshold in ground.cxx\n");
 360                 ground_network_path_type emptyPath;
 361                 emptyPath.erase(emptyPath.begin(), emptyPath.end());
 362                 return(emptyPath);
 363         }
 364         return GetShortestPath(A, b);
 365 }
 366
 367 // A shortest path algorithm from memory (ie. I can't find the bl&*dy book again!)
 368 // I'm sure there must be enchancements that we can make to this, such as biasing the
 369 // order in which the nodes are searched out from in favour of those geographically
 370 // closer to the destination.
 371 // Note that we are working with the master set of nodes and arcs so we mustn't change
 372 // or delete them -  we only delete the paths that we create during the algorithm.
 373 ground_network_path_type FGGround::GetShortestPath(node* A, node* B) {
 374         a_path* pathPtr;
 375         shortest_path_map_type pathMap;
 376         node_array_type nodesLeft;
 377
 378         // Debugging check
 379         int pathsCreated = 0;
 380
 381         // Initialise the algorithm
 382         nodesLeft.push_back(A);
 383         pathPtr = new a_path;
 384         pathsCreated++;
 385         pathPtr->path.push_back(A);
 386         pathPtr->cost = 0;
 387         pathMap[A->nodeID] = pathPtr;
 388         bool solution_found = false;    // Flag to indicate that at least one candidate path has been found
 389         int solution_cost = -1;                 // Cost of current best cost solution.  -1 indicates no solution found yet.
 390         a_path solution_path;
 391
 392         node* nPtr;     // nPtr is used to point to the node we are currently working with
 393
 394         while(nodesLeft.size()) {
 395                 //cout << "\n*****nodesLeft*****\n";
 396                 //for(unsigned int i=0; i<nodesLeft.size(); ++i) {
 397                         //cout << nodesLeft[i]->nodeID << '\n';
 398                 //}
 399                 //cout << "*******************\n\n";
 400                 nPtr = *nodesLeft.begin();              // Thought - definate optimization possibilities here in the choice of which nodes we process first.
 401                 nodesLeft.erase(nodesLeft.begin());
 402                 //cout << "Walking out from node " << nPtr->nodeID << '\n';
 403                 for(unsigned int i=0; i<nPtr->arcs.size(); ++i) {
 404                         //cout << "ARC TO " << ((nPtr->arcs[i]->n1 == nPtr->nodeID) ? nPtr->arcs[i]->n2 : nPtr->arcs[i]->n1) << '\n';
 405                 }
 406                 if((solution_found) && (solution_cost <= pathMap[nPtr->nodeID]->cost)) {
 407                         // Do nothing - we've already found a solution and this partial path is already more expensive
 408                 } else {
 409                         // This path could still be better than the current solution - check it out
 410                         for(unsigned int i=0; i<(nPtr->arcs.size()); i++) {
 411                                 // Map the new path against the end node, ie. *not* the one we just started with.
 412                                 unsigned int end_nodeID = ((nPtr->arcs[i]->n1 == nPtr->nodeID) ? nPtr->arcs[i]->n2 : nPtr->arcs[i]->n1);
 413                                 //cout << "end_nodeID = " << end_nodeID << '\n';
 414                                 //cout << "pathMap size is " << pathMap.size() << '\n';
 415                                 if(end_nodeID == nPtr->nodeID) {
 416                                         //cout << "Circular arc!\n";
 417                                         // Then its a circular arc - don't bother!!
 418                                         //nPtr->arcs.erase(nPtr->arcs.begin() + i);
 419                                 } else {
 420                                         // see if the end node is already in the map or not
 421                                         if(pathMap.find(end_nodeID) == pathMap.end()) {
 422                                                 //cout << "Not in the map" << endl;;
 423                                                 // Not in the map - easy!
 424                                                 pathPtr = new a_path;
 425                                                 pathsCreated++;
 426                                                 *pathPtr = *pathMap[nPtr->nodeID];      // *copy* the path
 427                                                 pathPtr->path.push_back(nPtr->arcs[i]);
 428                                                 pathPtr->path.push_back(network[end_nodeID]);
 429                                                 pathPtr->cost += nPtr->arcs[i]->distance;
 430                                                 pathMap[end_nodeID] = pathPtr;
 431                                                 nodesLeft.push_back(network[end_nodeID]);       // By definition this can't be in the list already, or
 432                                                 // it would also have been in the map and hence OR'd with this one.
 433                                                 if(end_nodeID == B->nodeID) {
 434                                                         //cout << "Solution found!!!" << endl;
 435                                                         // Since this node wasn't in the map this is by definition the first solution
 436                                                         solution_cost = pathPtr->cost;
 437                                                         solution_path = *pathPtr;
 438                                                         solution_found = true;
 439                                                 }
 440                                         } else {
 441                                                 //cout << "Already in the map" << endl;
 442                                                 // In the map - not so easy - need to get rid of an arc from the higher cost one.
 443                                                 //cout << "Current cost of node " << end_nodeID << " is " << pathMap[end_nodeID]->cost << endl;
 444                                                 int newCost = pathMap[nPtr->nodeID]->cost + nPtr->arcs[i]->distance;
 445                                                 //cout << "New cost is of node " << nPtr->nodeID << " is " << newCost << endl;
 446                                                 if(newCost >= pathMap[end_nodeID]->cost) {
 447                                                         // No need to do anything.
 448                                                         //cout << "Not doing anything!" << endl;
 449                                                 } else {
 450                                                         delete pathMap[end_nodeID];
 451                                                         pathsCreated--;
 452
 453                                                         pathPtr = new a_path;
 454                                                         pathsCreated++;
 455                                                         *pathPtr = *pathMap[nPtr->nodeID];      // *copy* the path
 456                                                         pathPtr->path.push_back(nPtr->arcs[i]);
 457                                                         pathPtr->path.push_back(network[end_nodeID]);
 458                                                         pathPtr->cost += nPtr->arcs[i]->distance;
 459                                                         pathMap[end_nodeID] = pathPtr;
 460
 461                                                         // We need to add this node to the list-to-do again to force a recalculation
 462                                                         // onwards from this node with the new lower cost to node cost.
 463                                                         nodesLeft.push_back(network[end_nodeID]);
 464
 465                                                         if(end_nodeID == B->nodeID) {
 466                                                                 //cout << "Solution found!!!" << endl;
 467                                                                 // Need to check if there is a previous better solution
 468                                                                 if((solution_cost < 0) || (pathPtr->cost < solution_cost)) {
 469                                                                         solution_cost = pathPtr->cost;
 470                                                                         solution_path = *pathPtr;
 471                                                                         solution_found = true;
 472                                                                 }
 473                                                         }
 474                                                 }
 475                                         }
 476                                 }
 477                         }
 478                 }
 479         }
 480
 481         // delete all the paths before returning
 482         shortest_path_map_iterator spItr = pathMap.begin();
 483         while(spItr != pathMap.end()) {
 484                 if(spItr->second != NULL) {
 485                         delete spItr->second;
 486                         --pathsCreated;
 487                 }
 488                 ++spItr;
 489         }
 490
 491         //cout << "pathsCreated = " << pathsCreated << '\n';
 492         if(pathsCreated > 0) {
 493                 SG_LOG(SG_GENERAL, SG_ALERT, "WARNING - Possible memory leak in FGGround::GetShortestPath\n\
 494                                                                           Please report to flightgear-devel@flightgear.org\n");
 495         }
 496
 497         //cout << (solution_found ? "Result: solution found\n" : "Result: no solution found\n");
 498         return(solution_path.path);             // TODO - we really ought to have a fallback position incase a solution isn't found.
 499 }
 500
 501
 502
 503 // Randomly or otherwise populate some of the gates with parked planes
 504 // (might eventually be done by the AIMgr if and when lots of AI traffic is generated)
 505
 506 // Return a list of exits from a given runway
 507 // It is up to the calling function to check for non-zero size of returned array before use
 508 node_array_type FGGround::GetExits(int rwyID) {
 509         return(runways[rwyID].exits);
 510 }
 511
 512 #if 0
 513 void FGGround::NewArrival(plane_rec plane) {
 514         // What are we going to do here?
 515         // We need to start a new ground_rec and add the plane_rec to it
 516         // We need to decide what gate we are going to clear it to.
 517         // Then we need to add clearing it to that gate to the pending transmissions queue? - or simply transmit?
 518         // Probably simply transmit for now and think about a transmission queue later if we need one.
 519         // We might need one though in order to add a little delay for response time.
 520         ground_rec* g = new ground_rec;
 521         g->plane_rec = plane;
 522         g->current_pos = ConvertWGS84ToXY(plane.pos);
 523         g->node = GetNode(g->current_pos);  // TODO - might need to sort out node/arc here
 524         AssignGate(g);
 525         g->cleared = false;
 526         ground_traffic.push_back(g);
 527         NextClearance(g);
 528 }
 529
 530 void FGGround::NewContact(plane_rec plane) {
 531         // This is a bit of a convienience function at the moment and is likely to change.
 532         if(at a gate or apron)
 533                 NewDeparture(plane);
 534         else
 535                 NewArrival(plane);
 536 }
 537
 538 void FGGround::NextClearance(ground_rec &g) {
 539         // Need to work out where we can clear g to.
 540         // Assume the pilot doesn't need progressive instructions
 541         // We *should* already have a gate or holding point assigned by the time we get here
 542         // but it wouldn't do any harm to check.
 543
 544         // For now though we will hardwire it to clear to the final destination.
 545 }
 546
 547 void FGGround::AssignGate(ground_rec &g) {
 548         // We'll cheat for now - since we only have the user's aircraft and a couple of airports implemented
 549         // we'll hardwire the gate!
 550         // In the long run the logic of which gate or area to send the plane to could be somewhat non-trivial.
 551 }
 552 #endif //0
 553