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104 lines
3.1 KiB
C++
104 lines
3.1 KiB
C++
// -*- C++ -*-
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/**
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* \file Graph.h
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* This file is part of LyX, the document processor.
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* Licence details can be found in the file COPYING.
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*
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* \author Dekel Tsur (original code)
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* \author Richard Kimberly Heck (re-implementation)
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*
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* Full author contact details are available in file CREDITS.
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*/
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#ifndef GRAPH_H
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#define GRAPH_H
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#include <list>
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#include <queue>
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#include <set>
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#include <vector>
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namespace lyx {
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/// Represents a directed graph, possibly with multiple edges
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/// connecting the vertices.
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class Graph {
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public:
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Graph() : numedges_(0) {}
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///
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typedef std::vector<int> EdgePath;
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/// \return a vector of the vertices from which "to" can be reached
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EdgePath const getReachableTo(int to, bool clear_visited);
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/// \return a vector of the reachable vertices, avoiding all "excludes"
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EdgePath const getReachable(int from, bool only_viewable, bool clear_visited,
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std::set<int> const & excludes = std::set<int>());
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/// can "from" be reached from "to"?
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bool isReachable(int from, int to);
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/// find a path from "from" to "to". always returns one of the
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/// shortest such paths.
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EdgePath const getPath(int from, int to);
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/// called repeatedly to build the graph
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void addEdge(int from, int to);
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/// reset the internal data structures
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void init(int size);
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private:
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///
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bool bfs_init(int, bool clear_visited, std::queue<int> & Q);
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/// these represent the arrows connecting the nodes of the graph.
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/// this is the basic representation of the graph: as a bunch of
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/// arrows.
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struct Arrow {
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///
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Arrow(int f, int t, int i):
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from(f), to(t), id(i) {}
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/// the vertex at the tail of the arrow
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int from;
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/// the vertex at the head
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int to;
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/// an id for this arrow, e.g., for use in describing paths
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/// through the graph
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int id;
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};
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/// a container for the arrows
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/// we use a list because we want pointers to the arrows,
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/// and a vector might invalidate them
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typedef std::list<Arrow> Arrows;
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Arrows arrows_;
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/// Represents a vertex of the graph. Note that we could recover
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/// the in_arrows and out_arrows from the Arrows, so these are in
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/// effect a kind of cache.
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struct Vertex {
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/// arrows that point at this one
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std::vector<Arrow *> in_arrows;
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/// arrows out from here
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std::vector<Arrow *> out_arrows;
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/// used in the search routines
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bool visited;
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};
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/// a container for the vertices
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/// the index into the vector functions as the identifier by which
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/// these are referenced in the Arrow struct
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/// the code making use of the Graph must keep track of the relation
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/// between these indices and the objects they represent. (in the case
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/// of Format, this is easy, since the Format objects already have ints
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/// as identifiers.)
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std::vector<Vertex> vertices_;
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/// a counter that we use to assign id's to the arrows
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/// FIXME This technique assumes a correspondence between the
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/// ids of the arrows and ids associated with Converters that
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/// seems kind of fragile. Perhaps a better solution would be
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/// to pass the ids as we create the arrows.
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int numedges_;
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};
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} // namespace lyx
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#endif //GRAPH_H
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