X-Git-Url: https://git.lyx.org/gitweb/?a=blobdiff_plain;f=src%2FGraph.cpp;h=bfb61dc3f3456bdad25e1df35c6e79dcc49a766e;hb=c393abbe12c360eec07a3dcbb5929e6b7c0ad329;hp=78e9f27954b82e5fd1deb39dd670537bd32d8f84;hpb=31d932df897c49b85fd91f4f662c799ec944d92a;p=lyx.git

diff --git a/src/Graph.cpp b/src/Graph.cpp
index 78e9f27954..bfb61dc3f3 100644
--- a/src/Graph.cpp
+++ b/src/Graph.cpp
@@ -3,7 +3,8 @@
  * This file is part of LyX, the document processor.
  * Licence details can be found in the file COPYING.
  *
- * \author Dekel Tsur
+ * \author Dekel Tsur (original code)
+ * \author Richard Heck (re-implementation)
  *
  * Full author contact details are available in file CREDITS.
  */
@@ -13,6 +14,9 @@
 #include "Graph.h"
 #include "Format.h"
 
+#include "support/debug.h"
+#include "support/lassert.h"
+
 #include <algorithm>
 
 using namespace std;
@@ -22,41 +26,60 @@ namespace lyx {
 
 bool Graph::bfs_init(int s, bool clear_visited)
 {
-	if (s < 0 || s >= vertices_.size())
+	if (s < 0)
 		return false;
 
 	Q_ = queue<int>();
 
-	if (clear_visited)
-		fill(visited_.begin(), visited_.end(), false);
-	if (visited_[s] == false) {
+	if (clear_visited) {
+		vector<Vertex>::iterator it = vertices_.begin();
+		vector<Vertex>::iterator en = vertices_.end();
+		for (; it != en; ++it)
+			it->visited = false;
+	}
+	if (!vertices_[s].visited) {
 		Q_.push(s);
-		visited_[s] = true;
+		vertices_[s].visited = true;
 	}
 	return true;
 }
 
 
+void Graph::clearPaths()
+{
+	vector<Vertex>::iterator it = vertices_.begin();
+	vector<Vertex>::iterator en = vertices_.end();
+	for (; it != en; ++it)
+		it->path.clear();
+}
+
+
 vector<int> const
-Graph::getReachableTo(int target, bool clear_visited)
+	Graph::getReachableTo(int target, bool clear_visited)
 {
 	vector<int> result;
 	if (!bfs_init(target, clear_visited))
 		return result;
 
+	// Here's the logic, which is shared by the other routines.
+	// Q_ holds a list of nodes we have been able to reach (in this
+	// case, reach backwards). It is initialized to the current node
+	// by bfs_init, and then we recurse, adding the nodes we can reach
+	// from the current node as we go. That makes it a breadth-first
+	// search.
 	while (!Q_.empty()) {
-		int const i = Q_.front();
+		int const current = Q_.front();
 		Q_.pop();
-		if (i != target || formats.get(target).name() != "lyx") {
-			result.push_back(i);
-		}
+		if (current != target || formats.get(target).name() != "lyx")
+			result.push_back(current);
 
-		vector<int>::iterator it = vertices_[i].in_vertices.begin();
-		vector<int>::iterator end = vertices_[i].in_vertices.end();
+		vector<Arrow *>::iterator it = vertices_[current].in_arrows.begin();
+		vector<Arrow *>::iterator const end = vertices_[current].in_arrows.end();
 		for (; it != end; ++it) {
-			if (!visited_[*it]) {
-				visited_[*it] = true;
-				Q_.push(*it);
+			const int cv = (*it)->from;
+			if (!vertices_[cv].visited) {
+				vertices_[cv].visited = true;
+				Q_.push(cv);
 			}
 		}
 	}
@@ -66,35 +89,37 @@ Graph::getReachableTo(int target, bool clear_visited)
 
 
 vector<int> const
-Graph::getReachable(int from, bool only_viewable,
-		    bool clear_visited)
+	Graph::getReachable(int from, bool only_viewable,
+		bool clear_visited)
 {
 	vector<int> result;
 	if (!bfs_init(from, clear_visited))
 		return result;
 
 	while (!Q_.empty()) {
-		int const i = Q_.front();
+		int const current = Q_.front();
 		Q_.pop();
-		Format const & format = formats.get(i);
+		Format const & format = formats.get(current);
 		if (!only_viewable || !format.viewer().empty())
-			result.push_back(i);
+			result.push_back(current);
 		else if (format.isChildFormat()) {
 			Format const * const parent =
 				formats.getFormat(format.parentFormat());
 			if (parent && !parent->viewer().empty())
-				result.push_back(i);
+				result.push_back(current);
 		}
 
-		vector<int>::const_iterator cit =
-			vertices_[i].out_vertices.begin();
-		vector<int>::const_iterator end =
-			vertices_[i].out_vertices.end();
-		for (; cit != end; ++cit)
-			if (!visited_[*cit]) {
-				visited_[*cit] = true;
-				Q_.push(*cit);
+		vector<Arrow *>::const_iterator cit =
+			vertices_[current].out_arrows.begin();
+		vector<Arrow *>::const_iterator end =
+			vertices_[current].out_arrows.end();
+		for (; cit != end; ++cit) {
+			int const cv = (*cit)->to;
+			if (!vertices_[cv].visited) {
+				vertices_[cv].visited = true;
+				Q_.push(cv);
 			}
+		}
 	}
 
 	return result;
@@ -106,7 +131,7 @@ bool Graph::isReachable(int from, int to)
 	if (from == to)
 		return true;
 
-	if (to < 0 || to >= vertices_.size() || !bfs_init(from))
+	if (to < 0 || !bfs_init(from))
 		return false;
 
 	while (!Q_.empty()) {
@@ -115,14 +140,15 @@ bool Graph::isReachable(int from, int to)
 		if (current == to)
 			return true;
 
-		vector<int>::const_iterator cit =
-			vertices_[current].out_vertices.begin();
-		vector<int>::const_iterator end =
-			vertices_[current].out_vertices.end();
+		vector<Arrow *>::const_iterator cit =
+			vertices_[current].out_arrows.begin();
+		vector<Arrow *>::const_iterator end =
+			vertices_[current].out_arrows.end();
 		for (; cit != end; ++cit) {
-			if (!visited_[*cit]) {
-				visited_[*cit] = true;
-				Q_.push(*cit);
+			int const cv = (*cit)->to;
+			if (!vertices_[cv].visited) {
+				vertices_[cv].visited = true;
+				Q_.push(cv);
 			}
 		}
 	}
@@ -133,48 +159,40 @@ bool Graph::isReachable(int from, int to)
 
 Graph::EdgePath const Graph::getPath(int from, int to)
 {
-	EdgePath path;
+	static const EdgePath path;
 	if (from == to)
 		return path;
 
-	if (to < 0 || to >= vertices_.size() || !bfs_init(from))
+	if (to < 0 || !bfs_init(from))
 		return path;
 
-	vector<int> prev_edge(formats.size());
-	vector<int> prev_vertex(formats.size());
-
-	bool found = false;
+	clearPaths();
 	while (!Q_.empty()) {
 		int const current = Q_.front();
 		Q_.pop();
-		if (current == to) {
-			found = true;
-			break;
-		}
 
-		vector<int>::const_iterator const beg =
-			vertices_[current].out_vertices.begin();
-		vector<int>::const_iterator cit = beg;
-		vector<int>::const_iterator end =
-			vertices_[current].out_vertices.end();
-		for (; cit != end; ++cit)
-			if (!visited_[*cit]) {
-				int const j = *cit;
-				visited_[j] = true;
-				Q_.push(j);
-				int const k = cit - beg;
-				prev_edge[j] = vertices_[current].out_edges[k];
-				prev_vertex[j] = current;
+		vector<Arrow *>::const_iterator cit =
+			vertices_[current].out_arrows.begin();
+		vector<Arrow *>::const_iterator end =
+			vertices_[current].out_arrows.end();
+		for (; cit != end; ++cit) {
+			int const cv = (*cit)->to;
+			if (!vertices_[cv].visited) {
+				vertices_[cv].visited = true;
+				Q_.push(cv);
+				// NOTE If we wanted to collect all the paths, then
+				// we just need to collect them here and not worry
+				// about "visited".
+				EdgePath lastpath = vertices_[(*cit)->from].path;
+				lastpath.push_back((*cit)->id);
+				vertices_[cv].path = lastpath;
 			}
+			if (cv == to) {
+				return vertices_[cv].path;
+			}
+		}
 	}
-	if (!found)
-		return path;
-
-	while (to != from) {
-		path.push_back(prev_edge[to]);
-		to = prev_vertex[to];
-	}
-	reverse(path.begin(), path.end());
+	// failure
 	return path;
 }
 
@@ -182,20 +200,43 @@ Graph::EdgePath const Graph::getPath(int from, int to)
 void Graph::init(int size)
 {
 	vertices_ = vector<Vertex>(size);
-	visited_.resize(size);
+	arrows_.clear();
 	numedges_ = 0;
 }
 
 
 void Graph::addEdge(int from, int to)
 {
-	vertices_[to].in_vertices.push_back(from);
-	vertices_[from].out_vertices.push_back(to);
-	vertices_[from].out_edges.push_back(numedges_++);
+	arrows_.push_back(Arrow(from, to, numedges_));
+	numedges_++;
+	Arrow * ar = &(arrows_.back());
+	vertices_[to].in_arrows.push_back(ar);
+	vertices_[from].out_arrows.push_back(ar);
 }
 
 
-vector<Graph::Vertex> Graph::vertices_;
+// At present, we do not need this debugging code, but
+// I am going to leave it here in case we need it again.
+#if 0
+void Graph::dumpGraph() const
+{
+	vector<Vertex>::const_iterator it = vertices_.begin();
+	vector<Vertex>::const_iterator en = vertices_.end();
+	for (; it != en; ++it) {
+		LYXERR0("Next vertex...");
+		LYXERR0("In arrows...");
+		std::vector<Arrow *>::const_iterator iit = it->in_arrows.begin();
+		std::vector<Arrow *>::const_iterator ien = it->in_arrows.end();
+		for (; iit != ien; ++iit)
+			LYXERR0("From " << (*iit)->from << " to " << (*iit)->to);
+		LYXERR0("Out arrows...");
+		iit = it->out_arrows.begin();
+		ien = it->out_arrows.end();
+		for (; iit != ien; ++iit)
+			LYXERR0("From " << (*iit)->from << " to " << (*iit)->to);
+	}
+}
+#endif
 
 
 } // namespace lyx