lemon/smart_graph.h
author Peter Kovacs <kpeter@inf.elte.hu>
Thu, 09 Oct 2008 10:09:44 +0200
changeset 313 64f8f7cc6168
parent 280 e7f8647ce760
child 341 d900fd1e760f
child 382 00c8843d491d
permissions -rw-r--r--
Fix several doxygen warnings
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/* -*- mode: C++; indent-tabs-mode: nil; -*-
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 *
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 * This file is a part of LEMON, a generic C++ optimization library.
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 *
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 * Copyright (C) 2003-2008
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 * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
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 * (Egervary Research Group on Combinatorial Optimization, EGRES).
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 *
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 * Permission to use, modify and distribute this software is granted
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 * provided that this copyright notice appears in all copies. For
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 * precise terms see the accompanying LICENSE file.
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 *
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 * This software is provided "AS IS" with no warranty of any kind,
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 * express or implied, and with no claim as to its suitability for any
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 * purpose.
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 *
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 */
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#ifndef LEMON_SMART_GRAPH_H
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#define LEMON_SMART_GRAPH_H
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///\ingroup graphs
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///\file
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///\brief SmartDigraph and SmartGraph classes.
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#include <vector>
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#include <lemon/core.h>
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#include <lemon/error.h>
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#include <lemon/bits/graph_extender.h>
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namespace lemon {
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  class SmartDigraph;
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  ///Base of SmartDigraph
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  ///Base of SmartDigraph
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  ///
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  class SmartDigraphBase {
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  protected:
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    struct NodeT
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    {
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      int first_in, first_out;
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      NodeT() {}
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    };
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    struct ArcT
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    {
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      int target, source, next_in, next_out;
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      ArcT() {}
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    };
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    std::vector<NodeT> nodes;
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    std::vector<ArcT> arcs;
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  public:
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    typedef SmartDigraphBase Graph;
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    class Node;
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    class Arc;
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  public:
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    SmartDigraphBase() : nodes(), arcs() { }
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    SmartDigraphBase(const SmartDigraphBase &_g)
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      : nodes(_g.nodes), arcs(_g.arcs) { }
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    typedef True NodeNumTag;
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    typedef True EdgeNumTag;
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    int nodeNum() const { return nodes.size(); }
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    int arcNum() const { return arcs.size(); }
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    int maxNodeId() const { return nodes.size()-1; }
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    int maxArcId() const { return arcs.size()-1; }
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    Node addNode() {
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      int n = nodes.size();
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      nodes.push_back(NodeT());
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      nodes[n].first_in = -1;
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      nodes[n].first_out = -1;
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      return Node(n);
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    }
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    Arc addArc(Node u, Node v) {
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      int n = arcs.size();
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      arcs.push_back(ArcT());
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      arcs[n].source = u._id;
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      arcs[n].target = v._id;
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      arcs[n].next_out = nodes[u._id].first_out;
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      arcs[n].next_in = nodes[v._id].first_in;
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      nodes[u._id].first_out = nodes[v._id].first_in = n;
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      return Arc(n);
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    }
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    void clear() {
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      arcs.clear();
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      nodes.clear();
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    }
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    Node source(Arc a) const { return Node(arcs[a._id].source); }
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    Node target(Arc a) const { return Node(arcs[a._id].target); }
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    static int id(Node v) { return v._id; }
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    static int id(Arc a) { return a._id; }
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    static Node nodeFromId(int id) { return Node(id);}
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    static Arc arcFromId(int id) { return Arc(id);}
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    bool valid(Node n) const {
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      return n._id >= 0 && n._id < static_cast<int>(nodes.size());
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    }
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    bool valid(Arc a) const {
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      return a._id >= 0 && a._id < static_cast<int>(arcs.size());
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    }
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    class Node {
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      friend class SmartDigraphBase;
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      friend class SmartDigraph;
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    protected:
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      int _id;
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      explicit Node(int id) : _id(id) {}
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    public:
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      Node() {}
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      Node (Invalid) : _id(-1) {}
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      bool operator==(const Node i) const {return _id == i._id;}
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      bool operator!=(const Node i) const {return _id != i._id;}
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      bool operator<(const Node i) const {return _id < i._id;}
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    };
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    class Arc {
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      friend class SmartDigraphBase;
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      friend class SmartDigraph;
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    protected:
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      int _id;
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      explicit Arc(int id) : _id(id) {}
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    public:
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      Arc() { }
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      Arc (Invalid) : _id(-1) {}
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      bool operator==(const Arc i) const {return _id == i._id;}
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      bool operator!=(const Arc i) const {return _id != i._id;}
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      bool operator<(const Arc i) const {return _id < i._id;}
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    };
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    void first(Node& node) const {
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      node._id = nodes.size() - 1;
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    }
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    static void next(Node& node) {
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      --node._id;
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    }
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    void first(Arc& arc) const {
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      arc._id = arcs.size() - 1;
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    }
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    static void next(Arc& arc) {
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      --arc._id;
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    }
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    void firstOut(Arc& arc, const Node& node) const {
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      arc._id = nodes[node._id].first_out;
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    }
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    void nextOut(Arc& arc) const {
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      arc._id = arcs[arc._id].next_out;
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    }
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    void firstIn(Arc& arc, const Node& node) const {
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      arc._id = nodes[node._id].first_in;
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    }
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    void nextIn(Arc& arc) const {
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      arc._id = arcs[arc._id].next_in;
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    }
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  };
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  typedef DigraphExtender<SmartDigraphBase> ExtendedSmartDigraphBase;
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  ///\ingroup graphs
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  ///
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  ///\brief A smart directed graph class.
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  ///
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  ///This is a simple and fast digraph implementation.
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  ///It is also quite memory efficient, but at the price
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  ///that <b> it does support only limited (only stack-like)
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  ///node and arc deletions</b>.
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  ///It conforms to the \ref concepts::Digraph "Digraph concept" with
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  ///an important extra feature that its maps are real \ref
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  ///concepts::ReferenceMap "reference map"s.
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  ///
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  ///\sa concepts::Digraph.
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  class SmartDigraph : public ExtendedSmartDigraphBase {
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  public:
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    typedef ExtendedSmartDigraphBase Parent;
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  private:
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    ///SmartDigraph is \e not copy constructible. Use DigraphCopy() instead.
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    ///SmartDigraph is \e not copy constructible. Use DigraphCopy() instead.
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    ///
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    SmartDigraph(const SmartDigraph &) : ExtendedSmartDigraphBase() {};
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    ///\brief Assignment of SmartDigraph to another one is \e not allowed.
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    ///Use DigraphCopy() instead.
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    ///Assignment of SmartDigraph to another one is \e not allowed.
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    ///Use DigraphCopy() instead.
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    void operator=(const SmartDigraph &) {}
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  public:
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    /// Constructor
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    /// Constructor.
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    ///
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    SmartDigraph() {};
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    ///Add a new node to the digraph.
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    /// \return the new node.
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    ///
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    Node addNode() { return Parent::addNode(); }
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    ///Add a new arc to the digraph.
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    ///Add a new arc to the digraph with source node \c s
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    ///and target node \c t.
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    ///\return the new arc.
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    Arc addArc(const Node& s, const Node& t) {
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      return Parent::addArc(s, t);
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    }
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    /// \brief Using this it is possible to avoid the superfluous memory
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    /// allocation.
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    /// Using this it is possible to avoid the superfluous memory
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    /// allocation: if you know that the digraph you want to build will
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    /// be very large (e.g. it will contain millions of nodes and/or arcs)
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    /// then it is worth reserving space for this amount before starting
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    /// to build the digraph.
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    /// \sa reserveArc
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    void reserveNode(int n) { nodes.reserve(n); };
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    /// \brief Using this it is possible to avoid the superfluous memory
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    /// allocation.
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    /// Using this it is possible to avoid the superfluous memory
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    /// allocation: if you know that the digraph you want to build will
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    /// be very large (e.g. it will contain millions of nodes and/or arcs)
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    /// then it is worth reserving space for this amount before starting
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    /// to build the digraph.
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    /// \sa reserveNode
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    void reserveArc(int m) { arcs.reserve(m); };
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    /// \brief Node validity check
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    ///
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    /// This function gives back true if the given node is valid,
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    /// ie. it is a real node of the graph.
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    ///
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    /// \warning A removed node (using Snapshot) could become valid again
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    /// when new nodes are added to the graph.
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    bool valid(Node n) const { return Parent::valid(n); }
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    /// \brief Arc validity check
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    ///
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    /// This function gives back true if the given arc is valid,
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    /// ie. it is a real arc of the graph.
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    ///
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    /// \warning A removed arc (using Snapshot) could become valid again
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    /// when new arcs are added to the graph.
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    bool valid(Arc a) const { return Parent::valid(a); }
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    ///Clear the digraph.
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    ///Erase all the nodes and arcs from the digraph.
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    ///
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    void clear() {
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      Parent::clear();
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    }
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    ///Split a node.
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    ///This function splits a node. First a new node is added to the digraph,
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    ///then the source of each outgoing arc of \c n is moved to this new node.
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    ///If \c connect is \c true (this is the default value), then a new arc
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    ///from \c n to the newly created node is also added.
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    ///\return The newly created node.
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    ///
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    ///\note The <tt>Arc</tt>s
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    ///referencing a moved arc remain
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    ///valid. However <tt>InArc</tt>'s and <tt>OutArc</tt>'s
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    ///may be invalidated.
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    ///\warning This functionality cannot be used together with the Snapshot
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    ///feature.
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    Node split(Node n, bool connect = true)
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    {
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      Node b = addNode();
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      nodes[b._id].first_out=nodes[n._id].first_out;
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      nodes[n._id].first_out=-1;
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      for(int i=nodes[b._id].first_out;i!=-1;i++) arcs[i].source=b._id;
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      if(connect) addArc(n,b);
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      return b;
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    }
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  public:
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    class Snapshot;
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  protected:
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    void restoreSnapshot(const Snapshot &s)
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    {
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      while(s.arc_num<arcs.size()) {
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        Arc arc = arcFromId(arcs.size()-1);
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        Parent::notifier(Arc()).erase(arc);
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        nodes[arcs.back().source].first_out=arcs.back().next_out;
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        nodes[arcs.back().target].first_in=arcs.back().next_in;
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        arcs.pop_back();
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      }
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      while(s.node_num<nodes.size()) {
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        Node node = nodeFromId(nodes.size()-1);
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        Parent::notifier(Node()).erase(node);
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        nodes.pop_back();
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      }
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    }
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  public:
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    ///Class to make a snapshot of the digraph and to restrore to it later.
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    ///Class to make a snapshot of the digraph and to restrore to it later.
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    ///
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    ///The newly added nodes and arcs can be removed using the
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    ///restore() function.
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    ///\note After you restore a state, you cannot restore
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    ///a later state, in other word you cannot add again the arcs deleted
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    ///by restore() using another one Snapshot instance.
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    ///
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    ///\warning If you do not use correctly the snapshot that can cause
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    ///either broken program, invalid state of the digraph, valid but
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    ///not the restored digraph or no change. Because the runtime performance
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    ///the validity of the snapshot is not stored.
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    class Snapshot
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    {
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      SmartDigraph *_graph;
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    protected:
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      friend class SmartDigraph;
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      unsigned int node_num;
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      unsigned int arc_num;
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    public:
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      ///Default constructor.
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      ///Default constructor.
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      ///To actually make a snapshot you must call save().
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      ///
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      Snapshot() : _graph(0) {}
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      ///Constructor that immediately makes a snapshot
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      ///This constructor immediately makes a snapshot of the digraph.
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      ///\param graph The digraph we make a snapshot of.
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      Snapshot(SmartDigraph &graph) : _graph(&graph) {
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        node_num=_graph->nodes.size();
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        arc_num=_graph->arcs.size();
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      }
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      ///Make a snapshot.
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      ///Make a snapshot of the digraph.
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      ///
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      ///This function can be called more than once. In case of a repeated
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      ///call, the previous snapshot gets lost.
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      ///\param graph The digraph we make the snapshot of.
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      void save(SmartDigraph &graph)
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      {
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        _graph=&graph;
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        node_num=_graph->nodes.size();
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        arc_num=_graph->arcs.size();
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      }
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      ///Undo the changes until a snapshot.
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      ///Undo the changes until a snapshot created by save().
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      ///
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      ///\note After you restored a state, you cannot restore
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      ///a later state, in other word you cannot add again the arcs deleted
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      ///by restore().
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      void restore()
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      {
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        _graph->restoreSnapshot(*this);
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      }
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    };
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  };
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  class SmartGraphBase {
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  protected:
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    struct NodeT {
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      int first_out;
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    };
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    struct ArcT {
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      int target;
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      int next_out;
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    };
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    std::vector<NodeT> nodes;
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    std::vector<ArcT> arcs;
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    int first_free_arc;
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  public:
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   423
    typedef SmartGraphBase Digraph;
deba@109
   424
deba@109
   425
    class Node;
deba@109
   426
    class Arc;
deba@109
   427
    class Edge;
alpar@209
   428
deba@109
   429
    class Node {
deba@109
   430
      friend class SmartGraphBase;
deba@109
   431
    protected:
deba@109
   432
deba@109
   433
      int _id;
deba@109
   434
      explicit Node(int id) { _id = id;}
deba@109
   435
deba@109
   436
    public:
deba@109
   437
      Node() {}
deba@109
   438
      Node (Invalid) { _id = -1; }
deba@109
   439
      bool operator==(const Node& node) const {return _id == node._id;}
deba@109
   440
      bool operator!=(const Node& node) const {return _id != node._id;}
deba@109
   441
      bool operator<(const Node& node) const {return _id < node._id;}
deba@109
   442
    };
deba@109
   443
deba@109
   444
    class Edge {
deba@109
   445
      friend class SmartGraphBase;
deba@109
   446
    protected:
deba@109
   447
deba@109
   448
      int _id;
deba@109
   449
      explicit Edge(int id) { _id = id;}
deba@109
   450
deba@109
   451
    public:
deba@109
   452
      Edge() {}
deba@109
   453
      Edge (Invalid) { _id = -1; }
deba@109
   454
      bool operator==(const Edge& arc) const {return _id == arc._id;}
deba@109
   455
      bool operator!=(const Edge& arc) const {return _id != arc._id;}
deba@109
   456
      bool operator<(const Edge& arc) const {return _id < arc._id;}
deba@109
   457
    };
deba@109
   458
deba@109
   459
    class Arc {
deba@109
   460
      friend class SmartGraphBase;
deba@109
   461
    protected:
deba@109
   462
deba@109
   463
      int _id;
deba@109
   464
      explicit Arc(int id) { _id = id;}
deba@109
   465
deba@109
   466
    public:
deba@238
   467
      operator Edge() const { 
deba@238
   468
        return _id != -1 ? edgeFromId(_id / 2) : INVALID; 
deba@238
   469
      }
deba@109
   470
deba@109
   471
      Arc() {}
deba@109
   472
      Arc (Invalid) { _id = -1; }
deba@109
   473
      bool operator==(const Arc& arc) const {return _id == arc._id;}
deba@109
   474
      bool operator!=(const Arc& arc) const {return _id != arc._id;}
deba@109
   475
      bool operator<(const Arc& arc) const {return _id < arc._id;}
deba@109
   476
    };
deba@109
   477
deba@109
   478
deba@109
   479
deba@109
   480
    SmartGraphBase()
deba@109
   481
      : nodes(), arcs() {}
deba@109
   482
alpar@209
   483
alpar@209
   484
    int maxNodeId() const { return nodes.size()-1; }
deba@109
   485
    int maxEdgeId() const { return arcs.size() / 2 - 1; }
deba@109
   486
    int maxArcId() const { return arcs.size()-1; }
deba@109
   487
deba@109
   488
    Node source(Arc e) const { return Node(arcs[e._id ^ 1].target); }
deba@109
   489
    Node target(Arc e) const { return Node(arcs[e._id].target); }
deba@109
   490
deba@125
   491
    Node u(Edge e) const { return Node(arcs[2 * e._id].target); }
deba@125
   492
    Node v(Edge e) const { return Node(arcs[2 * e._id + 1].target); }
deba@109
   493
deba@109
   494
    static bool direction(Arc e) {
deba@109
   495
      return (e._id & 1) == 1;
deba@109
   496
    }
deba@109
   497
deba@109
   498
    static Arc direct(Edge e, bool d) {
deba@109
   499
      return Arc(e._id * 2 + (d ? 1 : 0));
deba@109
   500
    }
deba@109
   501
alpar@209
   502
    void first(Node& node) const {
deba@109
   503
      node._id = nodes.size() - 1;
deba@109
   504
    }
deba@109
   505
deba@109
   506
    void next(Node& node) const {
deba@109
   507
      --node._id;
deba@109
   508
    }
deba@109
   509
alpar@209
   510
    void first(Arc& arc) const {
deba@109
   511
      arc._id = arcs.size() - 1;
deba@109
   512
    }
deba@109
   513
deba@109
   514
    void next(Arc& arc) const {
deba@109
   515
      --arc._id;
deba@109
   516
    }
deba@109
   517
alpar@209
   518
    void first(Edge& arc) const {
deba@109
   519
      arc._id = arcs.size() / 2 - 1;
deba@109
   520
    }
deba@109
   521
deba@109
   522
    void next(Edge& arc) const {
deba@109
   523
      --arc._id;
deba@109
   524
    }
deba@109
   525
deba@109
   526
    void firstOut(Arc &arc, const Node& v) const {
deba@109
   527
      arc._id = nodes[v._id].first_out;
deba@109
   528
    }
deba@109
   529
    void nextOut(Arc &arc) const {
deba@109
   530
      arc._id = arcs[arc._id].next_out;
deba@109
   531
    }
deba@109
   532
deba@109
   533
    void firstIn(Arc &arc, const Node& v) const {
deba@109
   534
      arc._id = ((nodes[v._id].first_out) ^ 1);
deba@109
   535
      if (arc._id == -2) arc._id = -1;
deba@109
   536
    }
deba@109
   537
    void nextIn(Arc &arc) const {
deba@109
   538
      arc._id = ((arcs[arc._id ^ 1].next_out) ^ 1);
deba@109
   539
      if (arc._id == -2) arc._id = -1;
deba@109
   540
    }
deba@109
   541
deba@109
   542
    void firstInc(Edge &arc, bool& d, const Node& v) const {
deba@109
   543
      int de = nodes[v._id].first_out;
deba@109
   544
      if (de != -1) {
deba@109
   545
        arc._id = de / 2;
deba@109
   546
        d = ((de & 1) == 1);
deba@109
   547
      } else {
deba@109
   548
        arc._id = -1;
deba@109
   549
        d = true;
deba@109
   550
      }
deba@109
   551
    }
deba@109
   552
    void nextInc(Edge &arc, bool& d) const {
deba@109
   553
      int de = (arcs[(arc._id * 2) | (d ? 1 : 0)].next_out);
deba@109
   554
      if (de != -1) {
deba@109
   555
        arc._id = de / 2;
deba@109
   556
        d = ((de & 1) == 1);
deba@109
   557
      } else {
deba@109
   558
        arc._id = -1;
alpar@209
   559
        d = true;
deba@109
   560
      }
deba@109
   561
    }
alpar@209
   562
deba@109
   563
    static int id(Node v) { return v._id; }
deba@109
   564
    static int id(Arc e) { return e._id; }
deba@109
   565
    static int id(Edge e) { return e._id; }
deba@109
   566
deba@109
   567
    static Node nodeFromId(int id) { return Node(id);}
deba@109
   568
    static Arc arcFromId(int id) { return Arc(id);}
deba@109
   569
    static Edge edgeFromId(int id) { return Edge(id);}
deba@109
   570
alpar@209
   571
    bool valid(Node n) const {
alpar@209
   572
      return n._id >= 0 && n._id < static_cast<int>(nodes.size());
deba@149
   573
    }
alpar@209
   574
    bool valid(Arc a) const {
deba@149
   575
      return a._id >= 0 && a._id < static_cast<int>(arcs.size());
deba@149
   576
    }
alpar@209
   577
    bool valid(Edge e) const {
alpar@209
   578
      return e._id >= 0 && 2 * e._id < static_cast<int>(arcs.size());
deba@149
   579
    }
deba@149
   580
alpar@209
   581
    Node addNode() {
deba@109
   582
      int n = nodes.size();
deba@109
   583
      nodes.push_back(NodeT());
deba@109
   584
      nodes[n].first_out = -1;
alpar@209
   585
deba@109
   586
      return Node(n);
deba@109
   587
    }
alpar@209
   588
deba@138
   589
    Edge addEdge(Node u, Node v) {
deba@109
   590
      int n = arcs.size();
deba@109
   591
      arcs.push_back(ArcT());
deba@109
   592
      arcs.push_back(ArcT());
alpar@209
   593
deba@109
   594
      arcs[n].target = u._id;
deba@109
   595
      arcs[n | 1].target = v._id;
deba@109
   596
deba@109
   597
      arcs[n].next_out = nodes[v._id].first_out;
deba@109
   598
      nodes[v._id].first_out = n;
deba@109
   599
alpar@209
   600
      arcs[n | 1].next_out = nodes[u._id].first_out;
deba@109
   601
      nodes[u._id].first_out = (n | 1);
deba@109
   602
deba@109
   603
      return Edge(n / 2);
deba@109
   604
    }
alpar@209
   605
deba@109
   606
    void clear() {
deba@109
   607
      arcs.clear();
deba@109
   608
      nodes.clear();
deba@109
   609
    }
deba@109
   610
deba@109
   611
  };
deba@109
   612
deba@109
   613
  typedef GraphExtender<SmartGraphBase> ExtendedSmartGraphBase;
deba@109
   614
deba@109
   615
  /// \ingroup graphs
deba@109
   616
  ///
deba@109
   617
  /// \brief A smart undirected graph class.
deba@109
   618
  ///
deba@109
   619
  /// This is a simple and fast graph implementation.
deba@109
   620
  /// It is also quite memory efficient, but at the price
deba@109
   621
  /// that <b> it does support only limited (only stack-like)
deba@109
   622
  /// node and arc deletions</b>.
alpar@209
   623
  /// Except from this it conforms to
deba@109
   624
  /// the \ref concepts::Graph "Graph concept".
deba@109
   625
  ///
deba@109
   626
  /// It also has an
deba@109
   627
  /// important extra feature that
deba@109
   628
  /// its maps are real \ref concepts::ReferenceMap "reference map"s.
deba@109
   629
  ///
deba@109
   630
  /// \sa concepts::Graph.
deba@109
   631
  ///
deba@109
   632
  class SmartGraph : public ExtendedSmartGraphBase {
deba@109
   633
  private:
deba@109
   634
deba@109
   635
    ///SmartGraph is \e not copy constructible. Use GraphCopy() instead.
deba@109
   636
deba@109
   637
    ///SmartGraph is \e not copy constructible. Use GraphCopy() instead.
deba@109
   638
    ///
deba@109
   639
    SmartGraph(const SmartGraph &) : ExtendedSmartGraphBase() {};
deba@109
   640
deba@109
   641
    ///\brief Assignment of SmartGraph to another one is \e not allowed.
deba@109
   642
    ///Use GraphCopy() instead.
deba@109
   643
deba@109
   644
    ///Assignment of SmartGraph to another one is \e not allowed.
deba@109
   645
    ///Use GraphCopy() instead.
deba@109
   646
    void operator=(const SmartGraph &) {}
deba@109
   647
deba@109
   648
  public:
deba@109
   649
deba@109
   650
    typedef ExtendedSmartGraphBase Parent;
deba@109
   651
deba@109
   652
    /// Constructor
alpar@209
   653
deba@109
   654
    /// Constructor.
deba@109
   655
    ///
deba@109
   656
    SmartGraph() {}
deba@109
   657
deba@109
   658
    ///Add a new node to the graph.
alpar@209
   659
deba@109
   660
    /// \return the new node.
deba@109
   661
    ///
deba@109
   662
    Node addNode() { return Parent::addNode(); }
alpar@209
   663
deba@109
   664
    ///Add a new edge to the graph.
alpar@209
   665
deba@109
   666
    ///Add a new edge to the graph with node \c s
deba@109
   667
    ///and \c t.
deba@109
   668
    ///\return the new edge.
alpar@209
   669
    Edge addEdge(const Node& s, const Node& t) {
alpar@209
   670
      return Parent::addEdge(s, t);
deba@109
   671
    }
deba@109
   672
deba@149
   673
    /// \brief Node validity check
deba@149
   674
    ///
deba@149
   675
    /// This function gives back true if the given node is valid,
alpar@209
   676
    /// ie. it is a real node of the graph.
deba@149
   677
    ///
deba@149
   678
    /// \warning A removed node (using Snapshot) could become valid again
deba@149
   679
    /// when new nodes are added to the graph.
deba@149
   680
    bool valid(Node n) const { return Parent::valid(n); }
deba@149
   681
deba@149
   682
    /// \brief Arc validity check
deba@149
   683
    ///
deba@149
   684
    /// This function gives back true if the given arc is valid,
alpar@209
   685
    /// ie. it is a real arc of the graph.
deba@149
   686
    ///
deba@149
   687
    /// \warning A removed arc (using Snapshot) could become valid again
deba@149
   688
    /// when new edges are added to the graph.
deba@149
   689
    bool valid(Arc a) const { return Parent::valid(a); }
deba@149
   690
deba@149
   691
    /// \brief Edge validity check
deba@149
   692
    ///
deba@149
   693
    /// This function gives back true if the given edge is valid,
alpar@209
   694
    /// ie. it is a real edge of the graph.
deba@149
   695
    ///
deba@149
   696
    /// \warning A removed edge (using Snapshot) could become valid again
deba@149
   697
    /// when new edges are added to the graph.
deba@149
   698
    bool valid(Edge e) const { return Parent::valid(e); }
deba@149
   699
deba@109
   700
    ///Clear the graph.
alpar@209
   701
deba@109
   702
    ///Erase all the nodes and edges from the graph.
deba@109
   703
    ///
deba@109
   704
    void clear() {
deba@109
   705
      Parent::clear();
deba@109
   706
    }
deba@109
   707
deba@109
   708
  public:
alpar@209
   709
deba@109
   710
    class Snapshot;
deba@109
   711
deba@109
   712
  protected:
deba@109
   713
deba@109
   714
    void saveSnapshot(Snapshot &s)
deba@109
   715
    {
deba@109
   716
      s._graph = this;
deba@109
   717
      s.node_num = nodes.size();
deba@109
   718
      s.arc_num = arcs.size();
deba@109
   719
    }
deba@109
   720
deba@109
   721
    void restoreSnapshot(const Snapshot &s)
deba@109
   722
    {
deba@109
   723
      while(s.arc_num<arcs.size()) {
deba@109
   724
        int n=arcs.size()-1;
deba@109
   725
        Edge arc=edgeFromId(n/2);
alpar@209
   726
        Parent::notifier(Edge()).erase(arc);
deba@109
   727
        std::vector<Arc> dir;
deba@109
   728
        dir.push_back(arcFromId(n));
deba@109
   729
        dir.push_back(arcFromId(n-1));
alpar@209
   730
        Parent::notifier(Arc()).erase(dir);
alpar@209
   731
        nodes[arcs[n].target].first_out=arcs[n].next_out;
alpar@209
   732
        nodes[arcs[n-1].target].first_out=arcs[n-1].next_out;
alpar@209
   733
        arcs.pop_back();
alpar@209
   734
        arcs.pop_back();
deba@109
   735
      }
deba@109
   736
      while(s.node_num<nodes.size()) {
deba@109
   737
        int n=nodes.size()-1;
deba@109
   738
        Node node = nodeFromId(n);
alpar@209
   739
        Parent::notifier(Node()).erase(node);
alpar@209
   740
        nodes.pop_back();
deba@109
   741
      }
alpar@209
   742
    }
deba@109
   743
deba@109
   744
  public:
deba@109
   745
deba@109
   746
    ///Class to make a snapshot of the digraph and to restrore to it later.
deba@109
   747
deba@109
   748
    ///Class to make a snapshot of the digraph and to restrore to it later.
deba@109
   749
    ///
deba@109
   750
    ///The newly added nodes and arcs can be removed using the
deba@109
   751
    ///restore() function.
deba@109
   752
    ///
deba@109
   753
    ///\note After you restore a state, you cannot restore
deba@109
   754
    ///a later state, in other word you cannot add again the arcs deleted
deba@109
   755
    ///by restore() using another one Snapshot instance.
deba@109
   756
    ///
deba@109
   757
    ///\warning If you do not use correctly the snapshot that can cause
deba@109
   758
    ///either broken program, invalid state of the digraph, valid but
deba@109
   759
    ///not the restored digraph or no change. Because the runtime performance
deba@109
   760
    ///the validity of the snapshot is not stored.
alpar@209
   761
    class Snapshot
deba@109
   762
    {
deba@109
   763
      SmartGraph *_graph;
deba@109
   764
    protected:
deba@109
   765
      friend class SmartGraph;
deba@109
   766
      unsigned int node_num;
deba@109
   767
      unsigned int arc_num;
deba@109
   768
    public:
deba@109
   769
      ///Default constructor.
alpar@209
   770
deba@109
   771
      ///Default constructor.
deba@109
   772
      ///To actually make a snapshot you must call save().
deba@109
   773
      ///
deba@109
   774
      Snapshot() : _graph(0) {}
deba@109
   775
      ///Constructor that immediately makes a snapshot
alpar@209
   776
deba@109
   777
      ///This constructor immediately makes a snapshot of the digraph.
kpeter@313
   778
      ///\param graph The digraph we make a snapshot of.
deba@109
   779
      Snapshot(SmartGraph &graph) {
deba@109
   780
        graph.saveSnapshot(*this);
deba@109
   781
      }
deba@109
   782
deba@109
   783
      ///Make a snapshot.
deba@109
   784
deba@109
   785
      ///Make a snapshot of the graph.
deba@109
   786
      ///
deba@109
   787
      ///This function can be called more than once. In case of a repeated
deba@109
   788
      ///call, the previous snapshot gets lost.
kpeter@313
   789
      ///\param graph The digraph we make the snapshot of.
alpar@209
   790
      void save(SmartGraph &graph)
deba@109
   791
      {
deba@109
   792
        graph.saveSnapshot(*this);
deba@109
   793
      }
deba@109
   794
deba@109
   795
      ///Undo the changes until a snapshot.
alpar@209
   796
deba@109
   797
      ///Undo the changes until a snapshot created by save().
deba@109
   798
      ///
deba@109
   799
      ///\note After you restored a state, you cannot restore
deba@109
   800
      ///a later state, in other word you cannot add again the arcs deleted
deba@109
   801
      ///by restore().
deba@109
   802
      void restore()
deba@109
   803
      {
deba@109
   804
        _graph->restoreSnapshot(*this);
deba@109
   805
      }
deba@109
   806
    };
deba@109
   807
  };
alpar@209
   808
deba@109
   809
} //namespace lemon
deba@109
   810
deba@109
   811
deba@109
   812
#endif //LEMON_SMART_GRAPH_H