src/Graph.cpp

   1 /**
   2  * \file Graph.cpp
   3  * This file is part of LyX, the document processor.
   4  * Licence details can be found in the file COPYING.
   5  *
   6  * \author Dekel Tsur (original code)
   7  * \author Richard Heck (re-implementation)
   8  *
   9  * Full author contact details are available in file CREDITS.
  10  */
  11
  12 #include <config.h>
  13
  14 #include "Graph.h"
  15 #include "Format.h"
  16
  17 #include "support/debug.h"
  18 #include "support/lassert.h"
  19
  20 #include <algorithm>
  21
  22 using namespace std;
  23
  24 namespace lyx {
  25
  26
  27 bool Graph::bfs_init(int s, bool clear_visited, queue<int> & Q)
  28 {
  29         if (s < 0)
  30                 return false;
  31
  32         if (!Q.empty())
  33                 Q = queue<int>();
  34
  35         if (clear_visited) {
  36                 vector<Vertex>::iterator it = vertices_.begin();
  37                 vector<Vertex>::iterator en = vertices_.end();
  38                 for (; it != en; ++it)
  39                         it->visited = false;
  40         }
  41         if (!vertices_[s].visited) {
  42                 Q.push(s);
  43                 vertices_[s].visited = true;
  44         }
  45         return true;
  46 }
  47
  48
  49 Graph::EdgePath const
  50         Graph::getReachableTo(int target, bool clear_visited)
  51 {
  52         EdgePath result;
  53         queue<int> Q;
  54         if (!bfs_init(target, clear_visited, Q))
  55                 return result;
  56
  57         // Here's the logic, which is shared by the other routines.
  58         // Q holds a list of nodes we have been able to reach (in this
  59         // case, reach backwards). It is initialized to the current node
  60         // by bfs_init, and then we recurse, adding the nodes we can reach
  61         // from the current node as we go. That makes it a breadth-first
  62         // search.
  63         while (!Q.empty()) {
  64                 int const current = Q.front();
  65                 Q.pop();
  66                 if (current != target || formats.get(target).name() != "lyx")
  67                         result.push_back(current);
  68
  69                 vector<Arrow *>::iterator it = vertices_[current].in_arrows.begin();
  70                 vector<Arrow *>::iterator const end = vertices_[current].in_arrows.end();
  71                 for (; it != end; ++it) {
  72                         const int cv = (*it)->from;
  73                         if (!vertices_[cv].visited) {
  74                                 vertices_[cv].visited = true;
  75                                 Q.push(cv);
  76                         }
  77                 }
  78         }
  79
  80         return result;
  81 }
  82
  83
  84 Graph::EdgePath const
  85         Graph::getReachable(int from, bool only_viewable,
  86                 bool clear_visited)
  87 {
  88         EdgePath result;
  89         queue<int> Q;
  90         if (!bfs_init(from, clear_visited, Q))
  91                 return result;
  92
  93         while (!Q.empty()) {
  94                 int const current = Q.front();
  95                 Q.pop();
  96                 Format const & format = formats.get(current);
  97                 if (!only_viewable || !format.viewer().empty())
  98                         result.push_back(current);
  99                 else if (format.isChildFormat()) {
 100                         Format const * const parent =
 101                                 formats.getFormat(format.parentFormat());
 102                         if (parent && !parent->viewer().empty())
 103                                 result.push_back(current);
 104                 }
 105
 106                 vector<Arrow *>::const_iterator cit =
 107                         vertices_[current].out_arrows.begin();
 108                 vector<Arrow *>::const_iterator end =
 109                         vertices_[current].out_arrows.end();
 110                 for (; cit != end; ++cit) {
 111                         int const cv = (*cit)->to;
 112                         if (!vertices_[cv].visited) {
 113                                 vertices_[cv].visited = true;
 114                                 Q.push(cv);
 115                         }
 116                 }
 117         }
 118
 119         return result;
 120 }
 121
 122
 123 bool Graph::isReachable(int from, int to)
 124 {
 125         if (from == to)
 126                 return true;
 127
 128         queue<int> Q;
 129         if (to < 0 || !bfs_init(from, true, Q))
 130                 return false;
 131
 132         while (!Q.empty()) {
 133                 int const current = Q.front();
 134                 Q.pop();
 135                 if (current == to)
 136                         return true;
 137
 138                 vector<Arrow *>::const_iterator cit =
 139                         vertices_[current].out_arrows.begin();
 140                 vector<Arrow *>::const_iterator end =
 141                         vertices_[current].out_arrows.end();
 142                 for (; cit != end; ++cit) {
 143                         int const cv = (*cit)->to;
 144                         if (!vertices_[cv].visited) {
 145                                 vertices_[cv].visited = true;
 146                                 Q.push(cv);
 147                         }
 148                 }
 149         }
 150
 151         return false;
 152 }
 153
 154
 155 Graph::EdgePath const Graph::getPath(int from, int to)
 156 {
 157         if (from == to)
 158                 return EdgePath();
 159
 160         queue<int> Q;
 161         if (to < 0 || !bfs_init(from, true, Q))
 162                 return EdgePath();
 163
 164         vector<EdgePath> pathes;
 165         pathes.resize(vertices_.size());
 166         while (!Q.empty()) {
 167                 int const current = Q.front();
 168                 Q.pop();
 169
 170                 vector<Arrow *>::const_iterator cit =
 171                         vertices_[current].out_arrows.begin();
 172                 vector<Arrow *>::const_iterator end =
 173                         vertices_[current].out_arrows.end();
 174                 for (; cit != end; ++cit) {
 175                         int const cv = (*cit)->to;
 176                         if (!vertices_[cv].visited) {
 177                                 vertices_[cv].visited = true;
 178                                 Q.push(cv);
 179                                 // NOTE If we wanted to collect all the paths, then
 180                                 // we just need to collect them here and not worry
 181                                 // about "visited".
 182                                 EdgePath lastpath = pathes[(*cit)->from];
 183                                 lastpath.push_back((*cit)->id);
 184                                 pathes[cv] = lastpath;
 185                         }
 186                         if (cv == to) {
 187                                 return pathes[cv];
 188                         }
 189                 }
 190         }
 191         // failure
 192         return EdgePath();
 193 }
 194
 195
 196 void Graph::init(int size)
 197 {
 198         vertices_ = vector<Vertex>(size);
 199         arrows_.clear();
 200         numedges_ = 0;
 201 }
 202
 203
 204 void Graph::addEdge(int from, int to)
 205 {
 206         arrows_.push_back(Arrow(from, to, numedges_));
 207         numedges_++;
 208         Arrow * ar = &(arrows_.back());
 209         vertices_[to].in_arrows.push_back(ar);
 210         vertices_[from].out_arrows.push_back(ar);
 211 }
 212
 213
 214 // At present, we do not need this debugging code, but
 215 // I am going to leave it here in case we need it again.
 216 #if 0
 217 void Graph::dumpGraph() const
 218 {
 219         vector<Vertex>::const_iterator it = vertices_.begin();
 220         vector<Vertex>::const_iterator en = vertices_.end();
 221         for (; it != en; ++it) {
 222                 LYXERR0("Next vertex...");
 223                 LYXERR0("In arrows...");
 224                 std::vector<Arrow *>::const_iterator iit = it->in_arrows.begin();
 225                 std::vector<Arrow *>::const_iterator ien = it->in_arrows.end();
 226                 for (; iit != ien; ++iit)
 227                         LYXERR0("From " << (*iit)->from << " to " << (*iit)->to);
 228                 LYXERR0("Out arrows...");
 229                 iit = it->out_arrows.begin();
 230                 ien = it->out_arrows.end();
 231                 for (; iit != ien; ++iit)
 232                         LYXERR0("From " << (*iit)->from << " to " << (*iit)->to);
 233         }
 234 }
 235 #endif
 236
 237
 238 } // namespace lyx