src/signal.cpp

   1 /* $Id$ */
   2
   3 /*
   4  * This file is part of OpenTTD.
   5  * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
   6  * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
   7  * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
   8  */
   9
  10 /** @file signal.cpp functions related to rail signals updating */
  11
  12 #include "stdafx.h"
  13 #include "debug.h"
  14 #include "station_map.h"
  15 #include "tunnelbridge_map.h"
  16 #include "vehicle_func.h"
  17 #include "viewport_func.h"
  18 #include "train.h"
  19 #include "company_base.h"
  20 #include "logic_signals.h"
  21
  22 #include "safeguards.h"
  23
  24
  25 /** these are the maximums used for updating signal blocks */
  26 static const uint SIG_TBU_SIZE    =  64; ///< number of signals entering to block
  27 static const uint SIG_TBD_SIZE    = 256; ///< number of intersections - open nodes in current block
  28 static const uint SIG_GLOB_SIZE   = 128; ///< number of open blocks (block can be opened more times until detected)
  29 static const uint SIG_GLOB_UPDATE =  64; ///< how many items need to be in _globset to force update
  30
  31 assert_compile(SIG_GLOB_UPDATE <= SIG_GLOB_SIZE);
  32
  33 /** incidating trackbits with given enterdir */
  34 static const TrackBits _enterdir_to_trackbits[DIAGDIR_END] = {
  35         TRACK_BIT_3WAY_NE,
  36         TRACK_BIT_3WAY_SE,
  37         TRACK_BIT_3WAY_SW,
  38         TRACK_BIT_3WAY_NW
  39 };
  40
  41 /** incidating trackdirbits with given enterdir */
  42 static const TrackdirBits _enterdir_to_trackdirbits[DIAGDIR_END] = {
  43         TRACKDIR_BIT_X_SW | TRACKDIR_BIT_UPPER_W | TRACKDIR_BIT_RIGHT_S,
  44         TRACKDIR_BIT_Y_NW | TRACKDIR_BIT_LOWER_W | TRACKDIR_BIT_RIGHT_N,
  45         TRACKDIR_BIT_X_NE | TRACKDIR_BIT_LOWER_E | TRACKDIR_BIT_LEFT_N,
  46         TRACKDIR_BIT_Y_SE | TRACKDIR_BIT_UPPER_E | TRACKDIR_BIT_LEFT_S
  47 };
  48
  49 /**
  50  * Set containing 'items' items of 'tile and Tdir'
  51  * No tree structure is used because it would cause
  52  * slowdowns in most usual cases
  53  */
  54 template <typename Tdir, uint items>
  55 struct SmallSet {
  56 private:
  57         uint n;           // actual number of units
  58         bool overflowed;  // did we try to overflow the set?
  59         const char *name; // name, used for debugging purposes...
  60
  61         /** Element of set */
  62         struct SSdata {
  63                 TileIndex tile;
  64                 Tdir dir;
  65         } data[items];
  66
  67 public:
  68         /** Constructor - just set default values and 'name' */
  69         SmallSet(const char *name) : n(0), overflowed(false), name(name) { }
  70
  71         /** Reset variables to default values */
  72         void Reset()
  73         {
  74                 this->n = 0;
  75                 this->overflowed = false;
  76         }
  77
  78         /**
  79          * Returns value of 'overflowed'
  80          * @return did we try to overflow the set?
  81          */
  82         bool Overflowed()
  83         {
  84                 return this->overflowed;
  85         }
  86
  87         /**
  88          * Checks for empty set
  89          * @return is the set empty?
  90          */
  91         bool IsEmpty()
  92         {
  93                 return this->n == 0;
  94         }
  95
  96         /**
  97          * Checks for full set
  98          * @return is the set full?
  99          */
 100         bool IsFull()
 101         {
 102                 return this->n == lengthof(data);
 103         }
 104
 105         /**
 106          * Reads the number of items
 107          * @return current number of items
 108          */
 109         uint Items()
 110         {
 111                 return this->n;
 112         }
 113
 114
 115         /**
 116          * Tries to remove first instance of given tile and dir
 117          * @param tile tile
 118          * @param dir and dir to remove
 119          * @return element was found and removed
 120          */
 121         bool Remove(TileIndex tile, Tdir dir)
 122         {
 123                 for (uint i = 0; i < this->n; i++) {
 124                         if (this->data[i].tile == tile && this->data[i].dir == dir) {
 125                                 this->data[i] = this->data[--this->n];
 126                                 return true;
 127                         }
 128                 }
 129
 130                 return false;
 131         }
 132
 133         /**
 134          * Tries to find given tile and dir in the set
 135          * @param tile tile
 136          * @param dir and dir to find
 137          * @return true iff the tile & dir element was found
 138          */
 139         bool IsIn(TileIndex tile, Tdir dir)
 140         {
 141                 for (uint i = 0; i < this->n; i++) {
 142                         if (this->data[i].tile == tile && this->data[i].dir == dir) return true;
 143                 }
 144
 145                 return false;
 146         }
 147
 148         /**
 149          * Adds tile & dir into the set, checks for full set
 150          * Sets the 'overflowed' flag if the set was full
 151          * @param tile tile
 152          * @param dir and dir to add
 153          * @return true iff the item could be added (set wasn't full)
 154          */
 155         bool Add(TileIndex tile, Tdir dir)
 156         {
 157                 if (this->IsFull()) {
 158                         overflowed = true;
 159                         DEBUG(misc, 0, "SignalSegment too complex. Set %s is full (maximum %d)", name, items);
 160                         return false; // set is full
 161                 }
 162
 163                 this->data[this->n].tile = tile;
 164                 this->data[this->n].dir = dir;
 165                 this->n++;
 166
 167                 return true;
 168         }
 169
 170         /**
 171          * Reads the last added element into the set
 172          * @param tile pointer where tile is written to
 173          * @param dir pointer where dir is written to
 174          * @return false iff the set was empty
 175          */
 176         bool Get(TileIndex *tile, Tdir *dir)
 177         {
 178                 if (this->n == 0) return false;
 179
 180                 this->n--;
 181                 *tile = this->data[this->n].tile;
 182                 *dir = this->data[this->n].dir;
 183
 184                 return true;
 185         }
 186 };
 187
 188 static SmallSet<Trackdir, SIG_TBU_SIZE> _tbuset("_tbuset");         ///< set of signals that will be updated
 189 static SmallSet<DiagDirection, SIG_TBD_SIZE> _tbdset("_tbdset");    ///< set of open nodes in current signal block
 190 static SmallSet<DiagDirection, SIG_GLOB_SIZE> _globset("_globset"); ///< set of places to be updated in following runs
 191
 192
 193 /** Check whether there is a train on rail, not in a depot */
 194 static Vehicle *TrainOnTileEnum(Vehicle *v, void *)
 195 {
 196         if (v->type != VEH_TRAIN || Train::From(v)->track == TRACK_BIT_DEPOT) return NULL;
 197
 198         return v;
 199 }
 200
 201 /** Check whether there is a train only on ramp. */
 202 static Vehicle *TrainInWormholeTileEnum(Vehicle *v, void *data)
 203 {
 204         /* Only look for front engine or last wagon. */
 205         if (v->type != VEH_TRAIN || (v->Previous() != NULL && v->Next() != NULL)) return NULL;
 206         if (*(TileIndex *)data != TileVirtXY(v->x_pos, v->y_pos)) return NULL;
 207         return v;
 208 }
 209
 210 /**
 211  * Perform some operations before adding data into Todo set
 212  * The new and reverse direction is removed from _globset, because we are sure
 213  * it doesn't need to be checked again
 214  * Also, remove reverse direction from _tbdset
 215  * This is the 'core' part so the graph searching won't enter any tile twice
 216  *
 217  * @param t1 tile we are entering
 218  * @param d1 direction (tile side) we are entering
 219  * @param t2 tile we are leaving
 220  * @param d2 direction (tile side) we are leaving
 221  * @return false iff reverse direction was in Todo set
 222  */
 223 static inline bool CheckAddToTodoSet(TileIndex t1, DiagDirection d1, TileIndex t2, DiagDirection d2)
 224 {
 225         _globset.Remove(t1, d1); // it can be in Global but not in Todo
 226         _globset.Remove(t2, d2); // remove in all cases
 227
 228         assert(!_tbdset.IsIn(t1, d1)); // it really shouldn't be there already
 229
 230         if (_tbdset.Remove(t2, d2)) return false;
 231
 232         return true;
 233 }
 234
 235
 236 /**
 237  * Perform some operations before adding data into Todo set
 238  * The new and reverse direction is removed from Global set, because we are sure
 239  * it doesn't need to be checked again
 240  * Also, remove reverse direction from Todo set
 241  * This is the 'core' part so the graph searching won't enter any tile twice
 242  *
 243  * @param t1 tile we are entering
 244  * @param d1 direction (tile side) we are entering
 245  * @param t2 tile we are leaving
 246  * @param d2 direction (tile side) we are leaving
 247  * @return false iff the Todo buffer would be overrun
 248  */
 249 static inline bool MaybeAddToTodoSet(TileIndex t1, DiagDirection d1, TileIndex t2, DiagDirection d2)
 250 {
 251         if (!CheckAddToTodoSet(t1, d1, t2, d2)) return true;
 252
 253         return _tbdset.Add(t1, d1);
 254 }
 255
 256
 257 /** Current signal block state flags */
 258 enum SigFlags {
 259         SF_NONE   = 0,
 260         SF_TRAIN  = 1 << 0, ///< train found in segment
 261         SF_EXIT   = 1 << 1, ///< exitsignal found
 262         SF_EXIT2  = 1 << 2, ///< two or more exits found
 263         SF_GREEN  = 1 << 3, ///< green exitsignal found
 264         SF_GREEN2 = 1 << 4, ///< two or more green exits found
 265         SF_FULL   = 1 << 5, ///< some of buffers was full, do not continue
 266         SF_PBS    = 1 << 6, ///< pbs signal found
 267 };
 268
 269 DECLARE_ENUM_AS_BIT_SET(SigFlags)
 270
 271
 272 /**
 273  * Search signal block
 274  *
 275  * @param owner owner whose signals we are updating
 276  * @return SigFlags
 277  */
 278 static SigFlags ExploreSegment(Owner owner)
 279 {
 280         SigFlags flags = SF_NONE;
 281
 282         TileIndex tile;
 283         DiagDirection enterdir;
 284
 285         while (_tbdset.Get(&tile, &enterdir)) {
 286                 TileIndex oldtile = tile; // tile we are leaving
 287                 DiagDirection exitdir = enterdir == INVALID_DIAGDIR ? INVALID_DIAGDIR : ReverseDiagDir(enterdir); // expected new exit direction (for straight line)
 288
 289                 switch (GetTileType(tile)) {
 290                         case MP_RAILWAY: {
 291                                 if (GetTileOwner(tile) != owner) continue; // do not propagate signals on others' tiles (remove for tracksharing)
 292
 293                                 if (IsRailDepot(tile)) {
 294                                         if (enterdir == INVALID_DIAGDIR) { // from 'inside' - train just entered or left the depot
 295                                                 if (!(flags & SF_TRAIN) && HasVehicleOnPos(tile, NULL, &TrainOnTileEnum)) flags |= SF_TRAIN;
 296                                                 exitdir = GetRailDepotDirection(tile);
 297                                                 tile += TileOffsByDiagDir(exitdir);
 298                                                 enterdir = ReverseDiagDir(exitdir);
 299                                                 break;
 300                                         } else if (enterdir == GetRailDepotDirection(tile)) { // entered a depot
 301                                                 if (!(flags & SF_TRAIN) && HasVehicleOnPos(tile, NULL, &TrainOnTileEnum)) flags |= SF_TRAIN;
 302                                                 continue;
 303                                         } else {
 304                                                 continue;
 305                                         }
 306                                 }
 307
 308                                 assert(IsValidDiagDirection(enterdir));
 309                                 TrackBits tracks = GetTrackBits(tile); // trackbits of tile
 310                                 TrackBits tracks_masked = (TrackBits)(tracks & _enterdir_to_trackbits[enterdir]); // only incidating trackbits
 311
 312                                 if (tracks == TRACK_BIT_HORZ || tracks == TRACK_BIT_VERT) { // there is exactly one incidating track, no need to check
 313                                         tracks = tracks_masked;
 314                                         /* If no train detected yet, and there is not no train -> there is a train -> set the flag */
 315                                         if (!(flags & SF_TRAIN) && EnsureNoTrainOnTrackBits(tile, tracks).Failed()) flags |= SF_TRAIN;
 316                                 } else {
 317                                         if (tracks_masked == TRACK_BIT_NONE) continue; // no incidating track
 318                                         if (!(flags & SF_TRAIN) && HasVehicleOnPos(tile, NULL, &TrainOnTileEnum)) flags |= SF_TRAIN;
 319                                 }
 320
 321                                 if (HasSignals(tile)) { // there is exactly one track - not zero, because there is exit from this tile
 322                                         Track track = TrackBitsToTrack(tracks_masked); // mask TRACK_BIT_X and Y too
 323                                         if (HasSignalOnTrack(tile, track)) { // now check whole track, not trackdir
 324                                                 SignalType sig = GetSignalType(tile, track);
 325                                                 Trackdir trackdir = (Trackdir)FindFirstBit((tracks * 0x101) & _enterdir_to_trackdirbits[enterdir]);
 326                                                 Trackdir reversedir = ReverseTrackdir(trackdir);
 327                                                 /* add (tile, reversetrackdir) to 'to-be-updated' set when there is
 328                                                  * ANY conventional signal in REVERSE direction
 329                                                  * (if it is a presignal EXIT and it changes, it will be added to 'to-be-done' set later) */
 330                                                 if (HasSignalOnTrackdir(tile, reversedir)) {
 331                                                         if (IsPbsSignal(sig)) {
 332                                                                 flags |= SF_PBS;
 333                                                         } else if (!_tbuset.Add(tile, reversedir)) {
 334                                                                 return flags | SF_FULL;
 335                                                         }
 336                                                 }
 337                                                 if (HasSignalOnTrackdir(tile, trackdir) && !IsOnewaySignal(tile, track)) flags |= SF_PBS;
 338
 339                                                 /* if it is a presignal EXIT in OUR direction and we haven't found 2 green exits yes, do special check */
 340                                                 if (!(flags & SF_GREEN2) && IsPresignalExit(tile, track) && HasSignalOnTrackdir(tile, trackdir)) { // found presignal exit
 341                                                         if (flags & SF_EXIT) flags |= SF_EXIT2; // found two (or more) exits
 342                                                         flags |= SF_EXIT; // found at least one exit - allow for compiler optimizations
 343                                                         if (GetSignalStateByTrackdir(tile, trackdir) == SIGNAL_STATE_GREEN) { // found green presignal exit
 344                                                                 if (flags & SF_GREEN) flags |= SF_GREEN2;
 345                                                                 flags |= SF_GREEN;
 346                                                         }
 347                                                 }
 348
 349                                                 continue;
 350                                         }
 351                                 }
 352
 353                                 for (DiagDirection dir = DIAGDIR_BEGIN; dir < DIAGDIR_END; dir++) { // test all possible exit directions
 354                                         if (dir != enterdir && (tracks & _enterdir_to_trackbits[dir])) { // any track incidating?
 355                                                 TileIndex newtile = tile + TileOffsByDiagDir(dir);  // new tile to check
 356                                                 DiagDirection newdir = ReverseDiagDir(dir); // direction we are entering from
 357                                                 if (!MaybeAddToTodoSet(newtile, newdir, tile, dir)) return flags | SF_FULL;
 358                                         }
 359                                 }
 360
 361                                 continue; // continue the while() loop
 362                                 }
 363
 364                         case MP_STATION:
 365                                 if (!HasStationRail(tile)) continue;
 366                                 if (GetTileOwner(tile) != owner) continue;
 367                                 if (DiagDirToAxis(enterdir) != GetRailStationAxis(tile)) continue; // different axis
 368                                 if (IsStationTileBlocked(tile)) continue; // 'eye-candy' station tile
 369
 370                                 if (!(flags & SF_TRAIN) && HasVehicleOnPos(tile, NULL, &TrainOnTileEnum)) flags |= SF_TRAIN;
 371                                 tile += TileOffsByDiagDir(exitdir);
 372                                 break;
 373
 374                         case MP_ROAD:
 375                                 if (!IsLevelCrossing(tile)) continue;
 376                                 if (GetTileOwner(tile) != owner) continue;
 377                                 if (DiagDirToAxis(enterdir) == GetCrossingRoadAxis(tile)) continue; // different axis
 378
 379                                 if (!(flags & SF_TRAIN) && HasVehicleOnPos(tile, NULL, &TrainOnTileEnum)) flags |= SF_TRAIN;
 380                                 tile += TileOffsByDiagDir(exitdir);
 381                                 break;
 382
 383                         case MP_TUNNELBRIDGE: {
 384                                 if (GetTileOwner(tile) != owner) continue;
 385                                 if (GetTunnelBridgeTransportType(tile) != TRANSPORT_RAIL) continue;
 386                                 DiagDirection dir = GetTunnelBridgeDirection(tile);
 387
 388                                 if (IsTunnelBridgeWithSignalSimulation(tile)) {
 389                                         if (enterdir == INVALID_DIAGDIR) { // incoming from the wormhole
 390                                                 if (!(flags & SF_TRAIN) && IsTunnelBridgeSignalSimulationExit(tile)) { // tunnel entrence is ignored
 391                                                         if (HasVehicleOnPos(GetOtherTunnelBridgeEnd(tile), &tile, &TrainInWormholeTileEnum)) flags |= SF_TRAIN;
 392                                                         if (!(flags & SF_TRAIN) && HasVehicleOnPos(tile, &tile, &TrainInWormholeTileEnum)) flags |= SF_TRAIN;
 393                                                 }
 394                                                 if (IsTunnelBridgeSignalSimulationExit(tile) && !_tbuset.Add(tile, INVALID_TRACKDIR)) {
 395                                                         return flags | SF_FULL;
 396                                                 }
 397                                                 enterdir = dir;
 398                                                 exitdir = ReverseDiagDir(dir);
 399                                                 tile += TileOffsByDiagDir(exitdir); // just skip to next tile
 400                                         } else { // NOT incoming from the wormhole!
 401                                                 if (ReverseDiagDir(enterdir) != dir) continue;
 402                                                 if (IsTunnelBridgeSignalSimulationExit(tile)) {
 403                                                         if (IsTunnelBridgePBS(tile)) {
 404                                                                 flags |= SF_PBS;
 405                                                         } else if (!_tbuset.Add(tile, INVALID_TRACKDIR)) {
 406                                                                 return flags | SF_FULL;
 407                                                         }
 408                                                 }
 409                                                 if (!(flags & SF_TRAIN)) {
 410                                                         if (HasVehicleOnPos(tile, &tile, &TrainInWormholeTileEnum)) flags |= SF_TRAIN;
 411                                                         if (!(flags & SF_TRAIN) && IsTunnelBridgeSignalSimulationExit(tile)) {
 412                                                                 if (HasVehicleOnPos(GetOtherTunnelBridgeEnd(tile), &tile, &TrainInWormholeTileEnum)) flags |= SF_TRAIN;
 413                                                         }
 414                                                 }
 415                                                 continue;
 416                                         }
 417                                 } else {
 418                                         if (enterdir == INVALID_DIAGDIR) { // incoming from the wormhole
 419                                                 if (!(flags & SF_TRAIN) && HasVehicleOnPos(tile, NULL, &TrainOnTileEnum)) flags |= SF_TRAIN;
 420                                                 enterdir = dir;
 421                                                 exitdir = ReverseDiagDir(dir);
 422                                                 tile += TileOffsByDiagDir(exitdir); // just skip to next tile
 423                                         } else { // NOT incoming from the wormhole!
 424                                                 if (ReverseDiagDir(enterdir) != dir) continue;
 425                                                 if (!(flags & SF_TRAIN) && HasVehicleOnPos(tile, NULL, &TrainOnTileEnum)) flags |= SF_TRAIN;
 426                                                 tile = GetOtherTunnelBridgeEnd(tile); // just skip to exit tile
 427                                                 enterdir = INVALID_DIAGDIR;
 428                                                 exitdir = INVALID_DIAGDIR;
 429                                         }
 430
 431                                 }
 432                                 }
 433                                 break;
 434
 435                         default:
 436                                 continue; // continue the while() loop
 437                 }
 438
 439                 if (!MaybeAddToTodoSet(tile, enterdir, oldtile, exitdir)) return flags | SF_FULL;
 440         }
 441
 442         return flags;
 443 }
 444
 445
 446 /**
 447  * Update signals around segment in _tbuset
 448  *
 449  * @param flags info about segment
 450  */
 451 static void UpdateSignalsAroundSegment(SigFlags flags)
 452 {
 453         TileIndex tile;
 454         Trackdir trackdir;
 455
 456         while (_tbuset.Get(&tile, &trackdir)) {
 457                 if (IsTileType(tile, MP_TUNNELBRIDGE) && IsTunnelBridgeSignalSimulationExit(tile)) {
 458                         if (IsTunnelBridgePBS(tile)) continue;
 459                         SignalState old_state = GetTunnelBridgeSignalState(tile);
 460                         SignalState new_state = (flags & SF_TRAIN) ? SIGNAL_STATE_RED : SIGNAL_STATE_GREEN;
 461                         if (old_state != new_state) {
 462                                 SetTunnelBridgeSignalState(tile, new_state);
 463                                 MarkTileDirtyByTile(tile);
 464                         }
 465                         continue;
 466                 }
 467
 468                 assert(HasSignalOnTrackdir(tile, trackdir));
 469
 470                 SignalType sig = GetSignalType(tile, TrackdirToTrack(trackdir));
 471                 SignalState newstate = SIGNAL_STATE_GREEN;
 472
 473                 if (sig == SIGTYPE_LOGIC) {
 474                         SignalProgram *program = FindSignalProgram(tile, TrackdirToTrack(trackdir));
 475
 476                         if (flags & SF_TRAIN) {
 477                                 /* Blocked by a train */
 478                                 newstate = SIGNAL_STATE_RED;
 479                                 program->blocked_by_train = true;
 480                         } else {
 481                                 /* Cleared by a train, we need to re-evaluate the state based on logic */
 482                                 newstate = program->Evaluate();
 483                                 program->blocked_by_train = false;
 484                         }
 485                 } else {
 486                         /* determine whether the new state is red */
 487                         if (flags & SF_TRAIN) {
 488                                 /* train in the segment */
 489                                 newstate = SIGNAL_STATE_RED;
 490                         } else {
 491                                 /* is it a bidir combo? - then do not count its other signal direction as exit */
 492                                 if (sig == SIGTYPE_COMBO && HasSignalOnTrackdir(tile, ReverseTrackdir(trackdir))) {
 493                                         /* at least one more exit */
 494                                         if ((flags & SF_EXIT2) &&
 495                                                         /* no green exit */
 496                                                         (!(flags & SF_GREEN) ||
 497                                                         /* only one green exit, and it is this one - so all other exits are red */
 498                                                         (!(flags & SF_GREEN2) && GetSignalStateByTrackdir(tile, ReverseTrackdir(trackdir)) == SIGNAL_STATE_GREEN))) {
 499                                                 newstate = SIGNAL_STATE_RED;
 500                                         }
 501                                 } else { // entry, at least one exit, no green exit
 502                                         if (IsPresignalEntry(tile, TrackdirToTrack(trackdir)) && (flags & SF_EXIT) && !(flags & SF_GREEN)) newstate = SIGNAL_STATE_RED;
 503                                 }
 504                         }
 505                 }
 506
 507                 /* only when the state changes */
 508                 if (newstate != GetSignalStateByTrackdir(tile, trackdir)) {
 509                         if (IsPresignalExit(tile, TrackdirToTrack(trackdir))) {
 510                                 /* for pre-signal exits, add block to the global set */
 511                                 DiagDirection exitdir = TrackdirToExitdir(ReverseTrackdir(trackdir));
 512                                 _globset.Add(tile, exitdir); // do not check for full global set, first update all signals
 513                         }
 514                         SetSignalStateByTrackdir(tile, trackdir, newstate);
 515                         MarkTileDirtyByTile(tile, ZOOM_LVL_DRAW_MAP);
 516
 517                         /* notify logic signals of the state change */
 518                         SignalStateChanged(tile, TrackdirToTrack(trackdir), 1);
 519                 }
 520         }
 521
 522 }
 523
 524
 525 /** Reset all sets after one set overflowed */
 526 static inline void ResetSets()
 527 {
 528         _tbuset.Reset();
 529         _tbdset.Reset();
 530         _globset.Reset();
 531 }
 532
 533
 534 /**
 535  * Updates blocks in _globset buffer
 536  *
 537  * @param owner company whose signals we are updating
 538  * @return state of the first block from _globset
 539  * @pre Company::IsValidID(owner)
 540  */
 541 static SigSegState UpdateSignalsInBuffer(Owner owner)
 542 {
 543         assert(Company::IsValidID(owner));
 544
 545         bool first = true;  // first block?
 546         SigSegState state = SIGSEG_FREE; // value to return
 547
 548         TileIndex tile;
 549         DiagDirection dir;
 550
 551         while (_globset.Get(&tile, &dir)) {
 552                 assert(_tbuset.IsEmpty());
 553                 assert(_tbdset.IsEmpty());
 554
 555                 /* After updating signal, data stored are always MP_RAILWAY with signals.
 556                  * Other situations happen when data are from outside functions -
 557                  * modification of railbits (including both rail building and removal),
 558                  * train entering/leaving block, train leaving depot...
 559                  */
 560                 switch (GetTileType(tile)) {
 561                         case MP_TUNNELBRIDGE:
 562                                 /* 'optimization assert' - do not try to update signals when it is not needed */
 563                                 assert(GetTunnelBridgeTransportType(tile) == TRANSPORT_RAIL);
 564                                 assert(dir == INVALID_DIAGDIR || dir == ReverseDiagDir(GetTunnelBridgeDirection(tile)));
 565                                 _tbdset.Add(tile, INVALID_DIAGDIR);  // we can safely start from wormhole centre
 566                                 if (!IsTunnelBridgeWithSignalSimulation(tile)) {  // Don't worry with other side of tunnel.
 567                                         _tbdset.Add(GetOtherTunnelBridgeEnd(tile), INVALID_DIAGDIR);
 568                                 }
 569                                 break;
 570
 571                         case MP_RAILWAY:
 572                                 if (IsRailDepot(tile)) {
 573                                         /* 'optimization assert' do not try to update signals in other cases */
 574                                         assert(dir == INVALID_DIAGDIR || dir == GetRailDepotDirection(tile));
 575                                         _tbdset.Add(tile, INVALID_DIAGDIR); // start from depot inside
 576                                         break;
 577                                 }
 578                                 FALLTHROUGH;
 579
 580                         case MP_STATION:
 581                         case MP_ROAD:
 582                                 if ((TrackStatusToTrackBits(GetTileTrackStatus(tile, TRANSPORT_RAIL, 0)) & _enterdir_to_trackbits[dir]) != TRACK_BIT_NONE) {
 583                                         /* only add to set when there is some 'interesting' track */
 584                                         _tbdset.Add(tile, dir);
 585                                         _tbdset.Add(tile + TileOffsByDiagDir(dir), ReverseDiagDir(dir));
 586                                         break;
 587                                 }
 588                                 FALLTHROUGH;
 589
 590                         default:
 591                                 /* jump to next tile */
 592                                 tile = tile + TileOffsByDiagDir(dir);
 593                                 dir = ReverseDiagDir(dir);
 594                                 if ((TrackStatusToTrackBits(GetTileTrackStatus(tile, TRANSPORT_RAIL, 0)) & _enterdir_to_trackbits[dir]) != TRACK_BIT_NONE) {
 595                                         _tbdset.Add(tile, dir);
 596                                         break;
 597                                 }
 598                                 /* happens when removing a rail that wasn't connected at one or both sides */
 599                                 continue; // continue the while() loop
 600                 }
 601
 602                 assert(!_tbdset.Overflowed()); // it really shouldn't overflow by these one or two items
 603                 assert(!_tbdset.IsEmpty()); // it wouldn't hurt anyone, but shouldn't happen too
 604
 605                 SigFlags flags = ExploreSegment(owner);
 606
 607                 if (first) {
 608                         first = false;
 609                         /* SIGSEG_FREE is set by default */
 610                         if (flags & SF_PBS) {
 611                                 state = SIGSEG_PBS;
 612                         } else if ((flags & SF_TRAIN) || ((flags & SF_EXIT) && !(flags & SF_GREEN)) || (flags & SF_FULL)) {
 613                                 state = SIGSEG_FULL;
 614                         }
 615                 }
 616
 617                 /* do not do anything when some buffer was full */
 618                 if (flags & SF_FULL) {
 619                         ResetSets(); // free all sets
 620                         break;
 621                 }
 622
 623                 UpdateSignalsAroundSegment(flags);
 624         }
 625
 626         return state;
 627 }
 628
 629
 630 static Owner _last_owner = INVALID_OWNER; ///< last owner whose track was put into _globset
 631
 632
 633 /**
 634  * Update signals in buffer
 635  * Called from 'outside'
 636  */
 637 void UpdateSignalsInBuffer()
 638 {
 639         if (!_globset.IsEmpty()) {
 640                 UpdateSignalsInBuffer(_last_owner);
 641                 _last_owner = INVALID_OWNER; // invalidate
 642         }
 643 }
 644
 645
 646 /**
 647  * Add track to signal update buffer
 648  *
 649  * @param tile tile where we start
 650  * @param track track at which ends we will update signals
 651  * @param owner owner whose signals we will update
 652  */
 653 void AddTrackToSignalBuffer(TileIndex tile, Track track, Owner owner)
 654 {
 655         static const DiagDirection _search_dir_1[] = {
 656                 DIAGDIR_NE, DIAGDIR_SE, DIAGDIR_NE, DIAGDIR_SE, DIAGDIR_SW, DIAGDIR_SE
 657         };
 658         static const DiagDirection _search_dir_2[] = {
 659                 DIAGDIR_SW, DIAGDIR_NW, DIAGDIR_NW, DIAGDIR_SW, DIAGDIR_NW, DIAGDIR_NE
 660         };
 661
 662         /* do not allow signal updates for two companies in one run */
 663         assert(_globset.IsEmpty() || owner == _last_owner);
 664
 665         _last_owner = owner;
 666
 667         _globset.Add(tile, _search_dir_1[track]);
 668         _globset.Add(tile, _search_dir_2[track]);
 669
 670         if (_globset.Items() >= SIG_GLOB_UPDATE) {
 671                 /* too many items, force update */
 672                 UpdateSignalsInBuffer(_last_owner);
 673                 _last_owner = INVALID_OWNER;
 674         }
 675 }
 676
 677
 678 /**
 679  * Add side of tile to signal update buffer
 680  *
 681  * @param tile tile where we start
 682  * @param side side of tile
 683  * @param owner owner whose signals we will update
 684  */
 685 void AddSideToSignalBuffer(TileIndex tile, DiagDirection side, Owner owner)
 686 {
 687         /* do not allow signal updates for two companies in one run */
 688         assert(_globset.IsEmpty() || owner == _last_owner);
 689
 690         _last_owner = owner;
 691
 692         _globset.Add(tile, side);
 693
 694         if (_globset.Items() >= SIG_GLOB_UPDATE) {
 695                 /* too many items, force update */
 696                 UpdateSignalsInBuffer(_last_owner);
 697                 _last_owner = INVALID_OWNER;
 698         }
 699 }
 700
 701 /**
 702  * Update signals, starting at one side of a tile
 703  * Will check tile next to this at opposite side too
 704  *
 705  * @see UpdateSignalsInBuffer()
 706  * @param tile tile where we start
 707  * @param side side of tile
 708  * @param owner owner whose signals we will update
 709  * @return the state of the signal segment
 710  */
 711 SigSegState UpdateSignalsOnSegment(TileIndex tile, DiagDirection side, Owner owner)
 712 {
 713         assert(_globset.IsEmpty());
 714         _globset.Add(tile, side);
 715
 716         return UpdateSignalsInBuffer(owner);
 717 }
 718
 719
 720 /**
 721  * Update signals at segments that are at both ends of
 722  * given (existent or non-existent) track
 723  *
 724  * @see UpdateSignalsInBuffer()
 725  * @param tile tile where we start
 726  * @param track track at which ends we will update signals
 727  * @param owner owner whose signals we will update
 728  */
 729 void SetSignalsOnBothDir(TileIndex tile, Track track, Owner owner)
 730 {
 731         assert(_globset.IsEmpty());
 732
 733         AddTrackToSignalBuffer(tile, track, owner);
 734         UpdateSignalsInBuffer(owner);
 735 }