source/libmarklin/route.cpp

   1 /* $Id$
   2
   3 This file is part of the MSP Märklin suite
   4 Copyright © 2007-2010  Mikkosoft Productions, Mikko Rasa
   5 Distributed under the GPL
   6 */
   7
   8 #include <queue>
   9 #include <msp/strings/formatter.h>
  10 #include "layout.h"
  11 #include "route.h"
  12 #include "track.h"
  13 #include "tracktype.h"
  14
  15 using namespace std;
  16 using namespace Msp;
  17
  18 namespace {
  19
  20 using namespace Marklin;
  21
  22 struct Node
  23 {
  24         const Track *track;
  25         unsigned ep;
  26         Node *prev;
  27         float dist;
  28
  29         Node():
  30                 track(0), ep(0), prev(0), dist(0)
  31         { }
  32
  33         Node(const Track &t, unsigned e):
  34                 track(&t), ep(e), prev(0), dist(0)
  35         { }
  36
  37         Node(const Track &t, unsigned e, Node &r, float d):
  38                 track(&t), ep(e), prev(&r), dist(prev->dist+d)
  39         { }
  40
  41         bool operator<(const Node &other) const
  42         { return dist>other.dist; }
  43 };
  44
  45 struct TrackMatch
  46 {
  47         const Track &track;
  48
  49         TrackMatch(const Track &t): track(t) { }
  50
  51         bool operator()(const Track &t) { return &t==&track; }
  52 };
  53
  54 template<typename Pred>
  55 list<const Track *> dijkstra(const Track &from, unsigned ep, Pred goal)
  56 {
  57         // XXX Fails to find some routes - should use track+ep as key
  58         map<const Track *, Node> track_nodes;
  59         priority_queue<Node> nodes;
  60         Node *final = 0;
  61
  62         nodes.push(Node(from, ep));
  63
  64         while(!nodes.empty())
  65         {
  66                 Node lowest = nodes.top();
  67                 nodes.pop();
  68
  69                 if(track_nodes.count(lowest.track))
  70                         continue;
  71
  72                 Node &ref = track_nodes[lowest.track] = lowest;
  73                 if(goal(*lowest.track))
  74                 {
  75                         final = &ref;
  76                         break;
  77                 }
  78
  79                 const TrackType &type = lowest.track->get_type();
  80                 const vector<Endpoint> &eps = type.get_endpoints();
  81                 const vector<Track *> &links = lowest.track->get_links();
  82                 for(unsigned i=0; i<eps.size(); ++i)
  83                 {
  84                         if(i==lowest.ep || !links[i] || track_nodes.count(links[i]))
  85                                 continue;
  86
  87                         unsigned mask = eps[i].paths&eps[lowest.ep].paths;
  88                         if(!mask)
  89                                 continue;
  90
  91                         unsigned path=0;
  92                         for(; !(mask&1); ++path, mask>>=1) ;
  93                         nodes.push(Node(*links[i], links[i]->get_endpoint_by_link(*lowest.track), ref, type.get_path_length(path)));
  94                 }
  95         }
  96
  97         if(!final)
  98                 throw InvalidParameterValue("Could not find a route");
  99
 100         list<const Track *> result;
 101         for(Node *node=final; node; node=node->prev)
 102                 result.push_front(node->track);
 103
 104         return result;
 105 }
 106
 107 }
 108
 109
 110 namespace Marklin {
 111
 112 Route::Route(Layout &l, const string &n):
 113         layout(l),
 114         name(n)
 115 {
 116         layout.add_route(*this);
 117         layout.signal_track_removed.connect(sigc::mem_fun(this, &Route::track_removed));
 118 }
 119
 120 Route::~Route()
 121 {
 122         layout.remove_route(*this);
 123 }
 124
 125 int Route::get_turnout(unsigned id) const
 126 {
 127         map<unsigned, int>::const_iterator i = turnouts.find(id);
 128         if(i!=turnouts.end())
 129                 return i->second;
 130         return -1;
 131 }
 132
 133 void Route::add_track(const Track &trk)
 134 {
 135         if(tracks.count(&trk))
 136                 return;
 137
 138         if(!tracks.empty())
 139         {
 140                 unsigned valid = check_validity(trk);
 141                 if(!(valid&1))
 142                         throw Exception("Not linked to existing tracks");
 143                 else if(!(valid&2))
 144                         throw Exception("Branching routes not allowed");
 145                 else if(!(valid&4))
 146                         throw Exception("Route must be smooth");
 147         }
 148
 149         tracks.insert(&trk);
 150         update_turnouts();
 151 }
 152
 153 void Route::add_tracks(const set<const Track *> &trks)
 154 {
 155         set<const Track *> pending;
 156         for(set<const Track *>::const_iterator i=trks.begin(); i!=trks.end(); ++i)
 157                 if(!tracks.count(*i))
 158                         pending.insert(*i);
 159
 160         while(!pending.empty())
 161         {
 162                 bool found = false;
 163                 for(set<const Track *>::const_iterator i=pending.begin(); i!=pending.end(); ++i)
 164                         if(tracks.empty() || check_validity(**i)==7)
 165                         {
 166                                 tracks.insert(*i);
 167                                 pending.erase(*i);
 168                                 found = true;
 169                                 break;
 170                         }
 171
 172                 if(!found)
 173                         throw Exception("Could not add all tracks to route");
 174         }
 175
 176         update_turnouts();
 177 }
 178
 179 void Route::save(list<DataFile::Statement> &st) const
 180 {
 181         for(map<unsigned, int>::const_iterator i=turnouts.begin(); i!=turnouts.end(); ++i)
 182                 st.push_back((DataFile::Statement("turnout"), i->first, i->second));
 183 }
 184
 185 void Route::update_turnouts()
 186 {
 187         set<unsigned> found;
 188         for(set<const Track *>::const_iterator i=tracks.begin(); i!=tracks.end(); ++i)
 189                 if(unsigned tid=(*i)->get_turnout_id())
 190                 {
 191                         found.insert(tid);
 192
 193                         const vector<Endpoint> &endpoints = (*i)->get_type().get_endpoints();
 194                         const vector<Track *> &links = (*i)->get_links();
 195
 196                         // Build a combined path mask from linked endpoints
 197                         unsigned mask = 15;
 198                         for(unsigned j=0; j<endpoints.size(); ++j)
 199                         {
 200                                 if(!tracks.count(links[j]))
 201                                         continue;
 202
 203                                 if(unsigned tid2=links[j]->get_turnout_id())
 204                                 {
 205                                         const Endpoint &ep = links[j]->get_type().get_endpoints()[links[j]->get_endpoint_by_link(**i)];
 206                                         int p = get_turnout(tid2);
 207                                         if(p>=0 && !(ep.paths&(1<<p)))
 208                                         {
 209                                                 // The linked track is a turnout and has a path which is incompatible with this endpoint
 210                                                 mask &= ~endpoints[j].paths;
 211                                                 continue;
 212                                         }
 213                                 }
 214                                 mask &= endpoints[j].paths;
 215                         }
 216
 217                         if(mask && !(mask&(mask-1)))
 218                         {
 219                                 // Exactly one possible choice, set the path accordingly
 220                                 unsigned path = 0;
 221                                 for(; (mask && !(mask&1)); mask>>=1, ++path) ;
 222                                 turnouts[tid] = path;
 223                         }
 224                         else if(!turnouts.count(tid))
 225                                 // More than one possible choice, and no existing entry - set as undecided
 226                                 turnouts[tid] = -1;
 227                 }
 228
 229         // Remove any turnouts that do not exist in the route
 230         for(map<unsigned, int>::iterator i=turnouts.begin(); i!=turnouts.end();)
 231         {
 232                 if(!found.count(i->first))
 233                         turnouts.erase(i++);
 234                 else
 235                         ++i;
 236         }
 237 }
 238
 239 unsigned Route::check_validity(const Track &trk) const
 240 {
 241         unsigned result = 4;
 242         for(set<const Track *>::const_iterator i=tracks.begin(); i!=tracks.end(); ++i)
 243         {
 244                 int epi=(*i)->get_endpoint_by_link(trk);
 245                 if(epi>=0)
 246                 {
 247                         // Linked to an existing track - good
 248                         result |= 1;
 249                         const vector<Endpoint> &endpoints = (*i)->get_type().get_endpoints();
 250                         if(unsigned tid=(*i)->get_turnout_id())
 251                         {
 252                                 int r = get_turnout(tid);
 253                                 if(r>=0)
 254                                 {
 255                                         // Linking to a turnout with path set is only good if we're continuing that path
 256                                         if(endpoints[epi].paths&(1<<r))
 257                                                 result |= 2;
 258                                 }
 259                                 else
 260                                 {
 261                                         // Linked to a turnout with no path set - find out other linked tracks
 262                                         unsigned count = 0;
 263                                         const vector<Track *> &links = (*i)->get_links();
 264                                         int epj = -1;
 265                                         for(unsigned k=0; k<endpoints.size(); ++k)
 266                                                 if(tracks.count(links[k]))
 267                                                 {
 268                                                         ++count;
 269                                                         epj = k;
 270                                                 }
 271
 272                                         // Only good if at most one other track is linked to the turnout
 273                                         if(count<=1)
 274                                         {
 275                                                 result |= 2;
 276                                                 if(epj>=0 && !(endpoints[epi].paths&endpoints[epj].paths))
 277                                                         // Impossible path through the turnout - not good
 278                                                         result &= 3;
 279                                         }
 280                                 }
 281                         }
 282                         else
 283                                 // Linked to something linear - good
 284                                 result |= 2;
 285                 }
 286         }
 287
 288         return result;
 289 }
 290
 291 void Route::track_removed(Track &t)
 292 {
 293         tracks.erase(&t);
 294 }
 295
 296 Route *Route::find(const Track &from, unsigned ep, const Track &to)
 297 {
 298         TrackMatch goal(to);
 299         list<const Track *> tracks = dijkstra(from, ep, goal);
 300
 301         static unsigned n = 0;
 302         Route *route = new Route(from.get_layout(), format("Route::find %d", ++n));
 303         for(list<const Track *>::iterator i=tracks.begin(); i!=tracks.end(); ++i)
 304                 route->add_track(**i);
 305
 306         return route;
 307 }
 308
 309
 310 Route::Loader::Loader(Route &r):
 311         DataFile::BasicLoader<Route>(r)
 312 {
 313         add("turnout", &Loader::turnout);
 314 }
 315
 316 void Route::Loader::turnout(unsigned id, unsigned path)
 317 {
 318         obj.turnouts[id] = path;
 319 }
 320
 321 } // namespace Marklin