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)
  28 {
  29         if (s < 0)
  30                 return false;
  31
  32         Q_ = queue<int>();
  33
  34         if (clear_visited) {
  35                 vector<Vertex>::iterator it = vertices_.begin();
  36                 vector<Vertex>::iterator en = vertices_.end();
  37                 for (; it != en; ++it)
  38                         it->visited = false;
  39         }
  40         if (!vertices_[s].visited) {
  41                 Q_.push(s);
  42                 vertices_[s].visited = true;
  43         }
  44         return true;
  45 }
  46
  47
  48 void Graph::clearPaths()
  49 {
  50         vector<Vertex>::iterator it = vertices_.begin();
  51         vector<Vertex>::iterator en = vertices_.end();
  52         for (; it != en; ++it)
  53                 it->path.clear();
  54 }
  55
  56
  57 vector<int> const
  58         Graph::getReachableTo(int target, bool clear_visited)
  59 {
  60         vector<int> result;
  61         if (!bfs_init(target, clear_visited))
  62                 return result;
  63
  64         // Here's the logic, which is shared by the other routines.
  65         // Q_ holds a list of nodes we have been able to reach (in this
  66         // case, reach backwards). It is initialized to the current node
  67         // by bfs_init, and then we recurse, adding the nodes we can reach
  68         // from the current node as we go. That makes it a breadth-first
  69         // search.
  70         while (!Q_.empty()) {
  71                 int const current = Q_.front();
  72                 Q_.pop();
  73                 if (current != target || formats.get(target).name() != "lyx")
  74                         result.push_back(current);
  75
  76                 vector<Arrow *>::iterator it = vertices_[current].in_arrows.begin();
  77                 vector<Arrow *>::iterator const end = vertices_[current].in_arrows.end();
  78                 for (; it != end; ++it) {
  79                         const int cv = (*it)->from;
  80                         if (!vertices_[cv].visited) {
  81                                 vertices_[cv].visited = true;
  82                                 Q_.push(cv);
  83                         }
  84                 }
  85         }
  86
  87         return result;
  88 }
  89
  90
  91 vector<int> const
  92         Graph::getReachable(int from, bool only_viewable,
  93                 bool clear_visited)
  94 {
  95         vector<int> result;
  96         if (!bfs_init(from, clear_visited))
  97                 return result;
  98
  99         while (!Q_.empty()) {
 100                 int const current = Q_.front();
 101                 Q_.pop();
 102                 Format const & format = formats.get(current);
 103                 if (!only_viewable || !format.viewer().empty())
 104                         result.push_back(current);
 105                 else if (format.isChildFormat()) {
 106                         Format const * const parent =
 107                                 formats.getFormat(format.parentFormat());
 108                         if (parent && !parent->viewer().empty())
 109                                 result.push_back(current);
 110                 }
 111
 112                 vector<Arrow *>::const_iterator cit =
 113                         vertices_[current].out_arrows.begin();
 114                 vector<Arrow *>::const_iterator end =
 115                         vertices_[current].out_arrows.end();
 116                 for (; cit != end; ++cit) {
 117                         int const cv = (*cit)->to;
 118                         if (!vertices_[cv].visited) {
 119                                 vertices_[cv].visited = true;
 120                                 Q_.push(cv);
 121                         }
 122                 }
 123         }
 124
 125         return result;
 126 }
 127
 128
 129 bool Graph::isReachable(int from, int to)
 130 {
 131         if (from == to)
 132                 return true;
 133
 134         if (to < 0 || !bfs_init(from))
 135                 return false;
 136
 137         while (!Q_.empty()) {
 138                 int const current = Q_.front();
 139                 Q_.pop();
 140                 if (current == to)
 141                         return true;
 142
 143                 vector<Arrow *>::const_iterator cit =
 144                         vertices_[current].out_arrows.begin();
 145                 vector<Arrow *>::const_iterator end =
 146                         vertices_[current].out_arrows.end();
 147                 for (; cit != end; ++cit) {
 148                         int const cv = (*cit)->to;
 149                         if (!vertices_[cv].visited) {
 150                                 vertices_[cv].visited = true;
 151                                 Q_.push(cv);
 152                         }
 153                 }
 154         }
 155
 156         return false;
 157 }
 158
 159
 160 Graph::EdgePath const Graph::getPath(int from, int to)
 161 {
 162         static const EdgePath path;
 163         if (from == to)
 164                 return path;
 165
 166         if (to < 0 || !bfs_init(from))
 167                 return path;
 168
 169         clearPaths();
 170         while (!Q_.empty()) {
 171                 int const current = Q_.front();
 172                 Q_.pop();
 173
 174                 vector<Arrow *>::const_iterator cit =
 175                         vertices_[current].out_arrows.begin();
 176                 vector<Arrow *>::const_iterator end =
 177                         vertices_[current].out_arrows.end();
 178                 for (; cit != end; ++cit) {
 179                         int const cv = (*cit)->to;
 180                         if (!vertices_[cv].visited) {
 181                                 vertices_[cv].visited = true;
 182                                 Q_.push(cv);
 183                                 // NOTE If we wanted to collect all the paths, then
 184                                 // we just need to collect them here and not worry
 185                                 // about "visited".
 186                                 EdgePath lastpath = vertices_[(*cit)->from].path;
 187                                 lastpath.push_back((*cit)->id);
 188                                 vertices_[cv].path = lastpath;
 189                         }
 190                         if (cv == to) {
 191                                 return vertices_[cv].path;
 192                         }
 193                 }
 194         }
 195         // failure
 196         return path;
 197 }
 198
 199
 200 void Graph::init(int size)
 201 {
 202         vertices_ = vector<Vertex>(size);
 203         arrows_.clear();
 204         numedges_ = 0;
 205 }
 206
 207
 208 void Graph::addEdge(int from, int to)
 209 {
 210         arrows_.push_back(Arrow(from, to, numedges_));
 211         numedges_++;
 212         Arrow * ar = &(arrows_.back());
 213         vertices_[to].in_arrows.push_back(ar);
 214         vertices_[from].out_arrows.push_back(ar);
 215 }
 216
 217
 218 // At present, we do not need this debugging code, but
 219 // I am going to leave it here in case we need it again.
 220 #if 0
 221 void Graph::dumpGraph() const
 222 {
 223         vector<Vertex>::const_iterator it = vertices_.begin();
 224         vector<Vertex>::const_iterator en = vertices_.end();
 225         for (; it != en; ++it) {
 226                 LYXERR0("Next vertex...");
 227                 LYXERR0("In arrows...");
 228                 std::vector<Arrow *>::const_iterator iit = it->in_arrows.begin();
 229                 std::vector<Arrow *>::const_iterator ien = it->in_arrows.end();
 230                 for (; iit != ien; ++iit)
 231                         LYXERR0("From " << (*iit)->from << " to " << (*iit)->to);
 232                 LYXERR0("Out arrows...");
 233                 iit = it->out_arrows.begin();
 234                 ien = it->out_arrows.end();
 235                 for (; iit != ien; ++iit)
 236                         LYXERR0("From " << (*iit)->from << " to " << (*iit)->to);
 237         }
 238 }
 239 #endif
 240
 241
 242 } // namespace lyx