# signal.cpp

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    00001 /* $Id: signal.cpp 17464 2009-09-07 21:01:24Z smatz $ */
    00002
    00003 /*
    00004  * This file is part of OpenTTD.
    00005  * 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.
    00006  * 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.
    00007  * 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/>.
    00008  */
    00009
    00012 #include "stdafx.h"
    00013 #include "debug.h"
    00014 #include "station_map.h"
    00015 #include "tunnelbridge_map.h"
    00016 #include "vehicle_func.h"
    00017 #include "functions.h"
    00018 #include "train.h"
    00019
    00020
    00022 enum {
    00023   SIG_TBU_SIZE    =  64,
    00024   SIG_TBD_SIZE    = 256,
    00025   SIG_GLOB_SIZE   = 128,
    00026   SIG_GLOB_UPDATE =  64,
    00027 };
    00028
    00029 assert_compile(SIG_GLOB_UPDATE <= SIG_GLOB_SIZE);
    00030
    00032 static const TrackBits _enterdir_to_trackbits[DIAGDIR_END] = {
    00033   TRACK_BIT_3WAY_NE,
    00034   TRACK_BIT_3WAY_SE,
    00035   TRACK_BIT_3WAY_SW,
    00036   TRACK_BIT_3WAY_NW
    00037 };
    00038
    00040 static const TrackdirBits _enterdir_to_trackdirbits[DIAGDIR_END] = {
    00041   TRACKDIR_BIT_X_SW | TRACKDIR_BIT_UPPER_W | TRACKDIR_BIT_RIGHT_S,
    00042   TRACKDIR_BIT_Y_NW | TRACKDIR_BIT_LOWER_W | TRACKDIR_BIT_RIGHT_N,
    00043   TRACKDIR_BIT_X_NE | TRACKDIR_BIT_LOWER_E | TRACKDIR_BIT_LEFT_N,
    00044   TRACKDIR_BIT_Y_SE | TRACKDIR_BIT_UPPER_E | TRACKDIR_BIT_LEFT_S
    00045 };
    00046
    00052 template <typename Tdir, uint items>
    00053 struct SmallSet {
    00054 private:
    00055   uint n;           // actual number of units
    00056   bool overflowed;  // did we try to oveflow the set?
    00057   const char *name; // name, used for debugging purposes...
    00058
    00060   struct SSdata {
    00061     TileIndex tile;
    00062     Tdir dir;
    00063   } data[items];
    00064
    00065 public:
    00067   SmallSet(const char *name) : n(0), overflowed(false), name(name) { }
    00068
    00070   void Reset()
    00071   {
    00072     this->n = 0;
    00073     this->overflowed = false;
    00074   }
    00075
    00080   bool Overflowed()
    00081   {
    00082     return this->overflowed;
    00083   }
    00084
    00089   bool IsEmpty()
    00090   {
    00091     return this->n == 0;
    00092   }
    00093
    00098   bool IsFull()
    00099   {
    00100     return this->n == lengthof(data);
    00101   }
    00102
    00107   uint Items()
    00108   {
    00109     return this->n;
    00110   }
    00111
    00112
    00119   bool Remove(TileIndex tile, Tdir dir)
    00120   {
    00121     for (uint i = 0; i < this->n; i++) {
    00122       if (this->data[i].tile == tile && this->data[i].dir == dir) {
    00123         this->data[i] = this->data[--this->n];
    00124         return true;
    00125       }
    00126     }
    00127
    00128     return false;
    00129   }
    00130
    00137   bool IsIn(TileIndex tile, Tdir dir)
    00138   {
    00139     for (uint i = 0; i < this->n; i++) {
    00140       if (this->data[i].tile == tile && this->data[i].dir == dir) return true;
    00141     }
    00142
    00143     return false;
    00144   }
    00145
    00153   bool Add(TileIndex tile, Tdir dir)
    00154   {
    00155     if (this->IsFull()) {
    00156       overflowed = true;
    00157       DEBUG(misc, 0, "SignalSegment too complex. Set %s is full (maximum %d)", name, items);
    00158       return false; // set is full
    00159     }
    00160
    00161     this->data[this->n].tile = tile;
    00162     this->data[this->n].dir = dir;
    00163     this->n++;
    00164
    00165     return true;
    00166   }
    00167
    00174   bool Get(TileIndex *tile, Tdir *dir)
    00175   {
    00176     if (this->n == 0) return false;
    00177
    00178     this->n--;
    00179     *tile = this->data[this->n].tile;
    00180     *dir = this->data[this->n].dir;
    00181
    00182     return true;
    00183   }
    00184 };
    00185
    00186 static SmallSet<Trackdir, SIG_TBU_SIZE> _tbuset("_tbuset");
    00187 static SmallSet<DiagDirection, SIG_TBD_SIZE> _tbdset("_tbdset");
    00188 static SmallSet<DiagDirection, SIG_GLOB_SIZE> _globset("_globset");
    00189
    00190
    00192 static Vehicle *TrainOnTileEnum(Vehicle *v, void *)
    00193 {
    00194   if (v->type != VEH_TRAIN || Train::From(v)->track == TRACK_BIT_DEPOT) return NULL;
    00195
    00196   return v;
    00197 }
    00198
    00199
    00213 static inline bool CheckAddToTodoSet(TileIndex t1, DiagDirection d1, TileIndex t2, DiagDirection d2)
    00214 {
    00215   _globset.Remove(t1, d1); // it can be in Global but not in Todo
    00216   _globset.Remove(t2, d2); // remove in all cases
    00217
    00218   assert(!_tbdset.IsIn(t1, d1)); // it really shouldn't be there already
    00219
    00220   if (_tbdset.Remove(t2, d2)) return false;
    00221
    00222   return true;
    00223 }
    00224
    00225
    00239 static inline bool MaybeAddToTodoSet(TileIndex t1, DiagDirection d1, TileIndex t2, DiagDirection d2)
    00240 {
    00241   if (!CheckAddToTodoSet(t1, d1, t2, d2)) return true;
    00242
    00243   return _tbdset.Add(t1, d1);
    00244 }
    00245
    00246
    00248 enum SigFlags {
    00249   SF_NONE   = 0,
    00250   SF_TRAIN  = 1 << 0,
    00251   SF_EXIT   = 1 << 1,
    00252   SF_EXIT2  = 1 << 2,
    00253   SF_GREEN  = 1 << 3,
    00254   SF_GREEN2 = 1 << 4,
    00255   SF_FULL   = 1 << 5,
    00256   SF_PBS    = 1 << 6,
    00257 };
    00258
    00259 DECLARE_ENUM_AS_BIT_SET(SigFlags)
    00260
    00261
    00262
    00268 static SigFlags ExploreSegment(Owner owner)
    00269 {
    00270   SigFlags flags = SF_NONE;
    00271
    00272   TileIndex tile;
    00273   DiagDirection enterdir;
    00274
    00275   while (_tbdset.Get(&tile, &enterdir)) {
    00276     TileIndex oldtile = tile; // tile we are leaving
    00277     DiagDirection exitdir = enterdir == INVALID_DIAGDIR ? INVALID_DIAGDIR : ReverseDiagDir(enterdir); // expected new exit direction (for straight line)
    00278
    00279     switch (GetTileType(tile)) {
    00280       case MP_RAILWAY: {
    00281         if (GetTileOwner(tile) != owner) continue; // do not propagate signals on others' tiles (remove for tracksharing)
    00282
    00283         if (IsRailDepot(tile)) {
    00284           if (enterdir == INVALID_DIAGDIR) { // from 'inside' - train just entered or left the depot
    00285             if (!(flags & SF_TRAIN) && HasVehicleOnPos(tile, NULL, &TrainOnTileEnum)) flags |= SF_TRAIN;
    00286             exitdir = GetRailDepotDirection(tile);
    00287             tile += TileOffsByDiagDir(exitdir);
    00288             enterdir = ReverseDiagDir(exitdir);
    00289             break;
    00290           } else if (enterdir == GetRailDepotDirection(tile)) { // entered a depot
    00291             if (!(flags & SF_TRAIN) && HasVehicleOnPos(tile, NULL, &TrainOnTileEnum)) flags |= SF_TRAIN;
    00292             continue;
    00293           } else {
    00294             continue;
    00295           }
    00296         }
    00297
    00298         TrackBits tracks = GetTrackBits(tile); // trackbits of tile
    00299         TrackBits tracks_masked = (TrackBits)(tracks & _enterdir_to_trackbits[enterdir]); // only incidating trackbits
    00300
    00301         if (tracks == TRACK_BIT_HORZ || tracks == TRACK_BIT_VERT) { // there is exactly one incidating track, no need to check
    00302           tracks = tracks_masked;
    00303           if (!(flags & SF_TRAIN) && HasVehicleOnPos(tile, &tracks, &EnsureNoTrainOnTrackProc)) flags |= SF_TRAIN;
    00304         } else {
    00305           if (tracks_masked == TRACK_BIT_NONE) continue; // no incidating track
    00306           if (!(flags & SF_TRAIN) && HasVehicleOnPos(tile, NULL, &TrainOnTileEnum)) flags |= SF_TRAIN;
    00307         }
    00308
    00309         if (HasSignals(tile)) { // there is exactly one track - not zero, because there is exit from this tile
    00310           Track track = TrackBitsToTrack(tracks_masked); // mask TRACK_BIT_X and Y too
    00311           if (HasSignalOnTrack(tile, track)) { // now check whole track, not trackdir
    00312             SignalType sig = GetSignalType(tile, track);
    00313             Trackdir trackdir = (Trackdir)FindFirstBit((tracks * 0x101) & _enterdir_to_trackdirbits[enterdir]);
    00314             Trackdir reversedir = ReverseTrackdir(trackdir);
    00315             /* add (tile, reversetrackdir) to 'to-be-updated' set when there is
    00316              * ANY conventional signal in REVERSE direction
    00317              * (if it is a presignal EXIT and it changes, it will be added to 'to-be-done' set later) */
    00318             if (HasSignalOnTrackdir(tile, reversedir)) {
    00319               if (IsPbsSignal(sig)) {
    00320                 flags |= SF_PBS;
    00321               } else if (!_tbuset.Add(tile, reversedir)) {
    00322                 return flags | SF_FULL;
    00323               }
    00324             }
    00325             if (HasSignalOnTrackdir(tile, trackdir) && !IsOnewaySignal(tile, track)) flags |= SF_PBS;
    00326
    00327             /* if it is a presignal EXIT in OUR direction and we haven't found 2 green exits yes, do special check */
    00328             if (!(flags & SF_GREEN2) && IsPresignalExit(tile, track) && HasSignalOnTrackdir(tile, trackdir)) { // found presignal exit
    00329               if (flags & SF_EXIT) flags |= SF_EXIT2; // found two (or more) exits
    00330               flags |= SF_EXIT; // found at least one exit - allow for compiler optimizations
    00331               if (GetSignalStateByTrackdir(tile, trackdir) == SIGNAL_STATE_GREEN) { // found green presignal exit
    00332                 if (flags & SF_GREEN) flags |= SF_GREEN2;
    00333                 flags |= SF_GREEN;
    00334               }
    00335             }
    00336
    00337             continue;
    00338           }
    00339         }
    00340
    00341         for (DiagDirection dir = DIAGDIR_BEGIN; dir < DIAGDIR_END; dir++) { // test all possible exit directions
    00342           if (dir != enterdir && (tracks & _enterdir_to_trackbits[dir])) { // any track incidating?
    00343             TileIndex newtile = tile + TileOffsByDiagDir(dir);  // new tile to check
    00344             DiagDirection newdir = ReverseDiagDir(dir); // direction we are entering from
    00345             if (!MaybeAddToTodoSet(newtile, newdir, tile, dir)) return flags | SF_FULL;
    00346           }
    00347         }
    00348
    00349         continue; // continue the while() loop
    00350         }
    00351
    00352       case MP_STATION:
    00353         if (!HasStationRail(tile)) continue;
    00354         if (GetTileOwner(tile) != owner) continue;
    00355         if (DiagDirToAxis(enterdir) != GetRailStationAxis(tile)) continue; // different axis
    00356         if (IsStationTileBlocked(tile)) continue; // 'eye-candy' station tile
    00357
    00358         if (!(flags & SF_TRAIN) && HasVehicleOnPos(tile, NULL, &TrainOnTileEnum)) flags |= SF_TRAIN;
    00359         tile += TileOffsByDiagDir(exitdir);
    00360         break;
    00361
    00362       case MP_ROAD:
    00363         if (!IsLevelCrossing(tile)) continue;
    00364         if (GetTileOwner(tile) != owner) continue;
    00365         if (DiagDirToAxis(enterdir) == GetCrossingRoadAxis(tile)) continue; // different axis
    00366
    00367         if (!(flags & SF_TRAIN) && HasVehicleOnPos(tile, NULL, &TrainOnTileEnum)) flags |= SF_TRAIN;
    00368         tile += TileOffsByDiagDir(exitdir);
    00369         break;
    00370
    00371       case MP_TUNNELBRIDGE: {
    00372         if (GetTileOwner(tile) != owner) continue;
    00373         if (GetTunnelBridgeTransportType(tile) != TRANSPORT_RAIL) continue;
    00374         DiagDirection dir = GetTunnelBridgeDirection(tile);
    00375
    00376         if (enterdir == INVALID_DIAGDIR) { // incoming from the wormhole
    00377           if (!(flags & SF_TRAIN) && HasVehicleOnPos(tile, NULL, &TrainOnTileEnum)) flags |= SF_TRAIN;
    00378           enterdir = dir;
    00379           exitdir = ReverseDiagDir(dir);
    00380           tile += TileOffsByDiagDir(exitdir); // just skip to next tile
    00381         } else { // NOT incoming from the wormhole!
    00382           if (ReverseDiagDir(enterdir) != dir) continue;
    00383           if (!(flags & SF_TRAIN) && HasVehicleOnPos(tile, NULL, &TrainOnTileEnum)) flags |= SF_TRAIN;
    00384           tile = GetOtherTunnelBridgeEnd(tile); // just skip to exit tile
    00385           enterdir = INVALID_DIAGDIR;
    00386           exitdir = INVALID_DIAGDIR;
    00387         }
    00388         }
    00389         break;
    00390
    00391       default:
    00392         continue; // continue the while() loop
    00393     }
    00394
    00395     if (!MaybeAddToTodoSet(tile, enterdir, oldtile, exitdir)) return flags | SF_FULL;
    00396   }
    00397
    00398   return flags;
    00399 }
    00400
    00401
    00407 static void UpdateSignalsAroundSegment(SigFlags flags)
    00408 {
    00409   TileIndex tile;
    00410   Trackdir trackdir;
    00411
    00412   while (_tbuset.Get(&tile, &trackdir)) {
    00413     assert(HasSignalOnTrackdir(tile, trackdir));
    00414
    00415     SignalType sig = GetSignalType(tile, TrackdirToTrack(trackdir));
    00416     SignalState newstate = SIGNAL_STATE_GREEN;
    00417
    00418     /* determine whether the new state is red */
    00419     if (flags & SF_TRAIN) {
    00420       /* train in the segment */
    00421       newstate = SIGNAL_STATE_RED;
    00422     } else {
    00423       /* is it a bidir combo? - then do not count its other signal direction as exit */
    00424       if (sig == SIGTYPE_COMBO && HasSignalOnTrackdir(tile, ReverseTrackdir(trackdir))) {
    00425         /* at least one more exit */
    00426         if ((flags & SF_EXIT2) &&
    00427             /* no green exit */
    00428             (!(flags & SF_GREEN) ||
    00429             /* only one green exit, and it is this one - so all other exits are red */
    00430             (!(flags & SF_GREEN2) && GetSignalStateByTrackdir(tile, ReverseTrackdir(trackdir)) == SIGNAL_STATE_GREEN))) {
    00431           newstate = SIGNAL_STATE_RED;
    00432         }
    00433       } else { // entry, at least one exit, no green exit
    00434         if (IsPresignalEntry(tile, TrackdirToTrack(trackdir)) && (flags & SF_EXIT) && !(flags & SF_GREEN)) newstate = SIGNAL_STATE_RED;
    00435       }
    00436     }
    00437
    00438     /* only when the state changes */
    00439     if (newstate != GetSignalStateByTrackdir(tile, trackdir)) {
    00440       if (IsPresignalExit(tile, TrackdirToTrack(trackdir))) {
    00441         /* for pre-signal exits, add block to the global set */
    00442         DiagDirection exitdir = TrackdirToExitdir(ReverseTrackdir(trackdir));
    00443         _globset.Add(tile, exitdir); // do not check for full global set, first update all signals
    00444       }
    00445       SetSignalStateByTrackdir(tile, trackdir, newstate);
    00446       MarkTileDirtyByTile(tile);
    00447     }
    00448   }
    00449
    00450 }
    00451
    00452
    00454 static inline void ResetSets()
    00455 {
    00456   _tbuset.Reset();
    00457   _tbdset.Reset();
    00458   _globset.Reset();
    00459 }
    00460
    00461
    00469 static SigSegState UpdateSignalsInBuffer(Owner owner)
    00470 {
    00471   assert(Company::IsValidID(owner));
    00472
    00473   bool first = true;  // first block?
    00474   SigSegState state = SIGSEG_FREE; // value to return
    00475
    00476   TileIndex tile;
    00477   DiagDirection dir;
    00478
    00479   while (_globset.Get(&tile, &dir)) {
    00480     assert(_tbuset.IsEmpty());
    00481     assert(_tbdset.IsEmpty());
    00482
    00483     /* After updating signal, data stored are always MP_RAILWAY with signals.
    00484      * Other situations happen when data are from outside functions -
    00485      * modification of railbits (including both rail building and removal),
    00486      * train entering/leaving block, train leaving depot...
    00487      */
    00488     switch (GetTileType(tile)) {
    00489       case MP_TUNNELBRIDGE:
    00490         /* 'optimization assert' - do not try to update signals when it is not needed */
    00491         assert(GetTunnelBridgeTransportType(tile) == TRANSPORT_RAIL);
    00492         assert(dir == INVALID_DIAGDIR || dir == ReverseDiagDir(GetTunnelBridgeDirection(tile)));
    00493         _tbdset.Add(tile, INVALID_DIAGDIR);  // we can safely start from wormhole centre
    00494         _tbdset.Add(GetOtherTunnelBridgeEnd(tile), INVALID_DIAGDIR);
    00495         break;
    00496
    00497       case MP_RAILWAY:
    00498         if (IsRailDepot(tile)) {
    00499           /* 'optimization assert' do not try to update signals in other cases */
    00500           assert(dir == INVALID_DIAGDIR || dir == GetRailDepotDirection(tile));
    00501           _tbdset.Add(tile, INVALID_DIAGDIR); // start from depot inside
    00502           break;
    00503         }
    00504         /* FALLTHROUGH */
    00505       case MP_STATION:
    00506       case MP_ROAD:
    00507         if ((TrackStatusToTrackBits(GetTileTrackStatus(tile, TRANSPORT_RAIL, 0)) & _enterdir_to_trackbits[dir]) != TRACK_BIT_NONE) {
    00508           /* only add to set when there is some 'interesting' track */
    00509           _tbdset.Add(tile, dir);
    00510           _tbdset.Add(tile + TileOffsByDiagDir(dir), ReverseDiagDir(dir));
    00511           break;
    00512         }
    00513         /* FALLTHROUGH */
    00514       default:
    00515         /* jump to next tile */
    00516         tile = tile + TileOffsByDiagDir(dir);
    00517         dir = ReverseDiagDir(dir);
    00518         if ((TrackStatusToTrackBits(GetTileTrackStatus(tile, TRANSPORT_RAIL, 0)) & _enterdir_to_trackbits[dir]) != TRACK_BIT_NONE) {
    00519           _tbdset.Add(tile, dir);
    00520           break;
    00521         }
    00522         /* happens when removing a rail that wasn't connected at one or both sides */
    00523         continue; // continue the while() loop
    00524     }
    00525
    00526     assert(!_tbdset.Overflowed()); // it really shouldn't overflow by these one or two items
    00527     assert(!_tbdset.IsEmpty()); // it wouldn't hurt anyone, but shouldn't happen too
    00528
    00529     SigFlags flags = ExploreSegment(owner);
    00530
    00531     if (first) {
    00532       first = false;
    00533       /* SIGSEG_FREE is set by default */
    00534       if (flags & SF_PBS) {
    00535         state = SIGSEG_PBS;
    00536       } else if ((flags & SF_TRAIN) || ((flags & SF_EXIT) && !(flags & SF_GREEN)) || (flags & SF_FULL)) {
    00537         state = SIGSEG_FULL;
    00538       }
    00539     }
    00540
    00541     /* do not do anything when some buffer was full */
    00542     if (flags & SF_FULL) {
    00543       ResetSets(); // free all sets
    00544       break;
    00545     }
    00546
    00547     UpdateSignalsAroundSegment(flags);
    00548   }
    00549
    00550   return state;
    00551 }
    00552
    00553
    00554 static Owner _last_owner = INVALID_OWNER;
    00555
    00556
    00561 void UpdateSignalsInBuffer()
    00562 {
    00563   if (!_globset.IsEmpty()) {
    00564     UpdateSignalsInBuffer(_last_owner);
    00565     _last_owner = INVALID_OWNER; // invalidate
    00566   }
    00567 }
    00568
    00569
    00577 void AddTrackToSignalBuffer(TileIndex tile, Track track, Owner owner)
    00578 {
    00579   static const DiagDirection _search_dir_1[] = {
    00580     DIAGDIR_NE, DIAGDIR_SE, DIAGDIR_NE, DIAGDIR_SE, DIAGDIR_SW, DIAGDIR_SE
    00581   };
    00582   static const DiagDirection _search_dir_2[] = {
    00583     DIAGDIR_SW, DIAGDIR_NW, DIAGDIR_NW, DIAGDIR_SW, DIAGDIR_NW, DIAGDIR_NE
    00584   };
    00585
    00586   /* do not allow signal updates for two companies in one run */
    00587   assert(_globset.IsEmpty() || owner == _last_owner);
    00588
    00589   _last_owner = owner;
    00590
    00591   _globset.Add(tile, _search_dir_1[track]);
    00592   _globset.Add(tile, _search_dir_2[track]);
    00593
    00594   if (_globset.Items() >= SIG_GLOB_UPDATE) {
    00595     /* too many items, force update */
    00596     UpdateSignalsInBuffer(_last_owner);
    00597     _last_owner = INVALID_OWNER;
    00598   }
    00599 }
    00600
    00601
    00609 void AddSideToSignalBuffer(TileIndex tile, DiagDirection side, Owner owner)
    00610 {
    00611   /* do not allow signal updates for two companies in one run */
    00612   assert(_globset.IsEmpty() || owner == _last_owner);
    00613
    00614   _last_owner = owner;
    00615
    00616   _globset.Add(tile, side);
    00617
    00618   if (_globset.Items() >= SIG_GLOB_UPDATE) {
    00619     /* too many items, force update */
    00620     UpdateSignalsInBuffer(_last_owner);
    00621     _last_owner = INVALID_OWNER;
    00622   }
    00623 }
    00624
    00635 SigSegState UpdateSignalsOnSegment(TileIndex tile, DiagDirection side, Owner owner)
    00636 {
    00637   assert(_globset.IsEmpty());
    00638   _globset.Add(tile, side);
    00639
    00640   return UpdateSignalsInBuffer(owner);
    00641 }
    00642
    00643
    00653 void SetSignalsOnBothDir(TileIndex tile, Track track, Owner owner)
    00654 {
    00655   assert(_globset.IsEmpty());
    00656
    00657   AddTrackToSignalBuffer(tile, track, owner);
    00658   UpdateSignalsInBuffer(owner);
    00659 }