RhodeCode

#define LEMON_PATH_H

#include <vector>

#include <algorithm>

#include <lemon/error.h>

#include <lemon/core.h>

#include <lemon/concepts/path.h>

namespace lemon {

  /// \addtogroup paths

  /// @{

  /// \brief A structure for representing directed paths in a digraph.

  ///

  /// A structure for representing directed path in a digraph.

  /// \tparam _Digraph The digraph type in which the path is.

  ///

  /// In a sense, the path can be treated as a list of arcs. The

  /// lemon path type stores just this list. As a consequence, it

  /// cannot enumerate the nodes of the path and the source node of

  /// a zero length path is undefined.

  ///

  /// This implementation is a back and front insertable and erasable

  /// path type. It can be indexed in O(1) time. The front and back

  /// insertion and erase is done in O(1) (amortized) time. The

  /// implementation uses two vectors for storing the front and back

  /// insertions.

  template <typename _Digraph>

  class Path {

  public:

    typedef _Digraph Digraph;

    typedef typename Digraph::Arc Arc;

    /// \brief Default constructor

    ///

    /// Default constructor

    Path() {}

    /// \brief Template copy constructor

    ///

    /// This constuctor initializes the path from any other path type.

    /// It simply makes a copy of the given path.

    template <typename CPath>

    Path(const CPath& cpath) {

    }

    /// \brief Template copy assignment

    ///

    /// This operator makes a copy of a path of any other type.

    template <typename CPath>

    Path& operator=(const CPath& cpath) {

      return *this;

    }

    /// \brief LEMON style iterator for path arcs

    ///

    /// This class is used to iterate on the arcs of the paths.

    class ArcIt {

      friend class Path;

    public:

      /// \brief Default constructor

      ArcIt() {}

      /// \brief Invalid constructor

      ArcIt(Invalid) : path(0), idx(-1) {}

      /// \brief Initializate the iterator to the first arc of path

      ArcIt(const Path &_path)

        : path(&_path), idx(_path.empty() ? -1 : 0) {}

    private:

      ArcIt(const Path &_path, int _idx)

        : path(&_path), idx(_idx) {}

    public:

      /// \brief Conversion to Arc

      operator const Arc&() const {

        return path->nth(idx);

      }

      /// \brief Next arc

      ArcIt& operator++() {

        ++idx;

        if (idx >= path->length()) idx = -1;

        return *this;

      }

      /// \brief Comparison operator

      bool operator==(const ArcIt& e) const { return idx==e.idx; }

      /// \brief Comparison operator

      bool operator!=(const ArcIt& e) const { return idx!=e.idx; }

      /// \brief Comparison operator

      bool operator<(const ArcIt& e) const { return idx<e.idx; }

    private:

      const Path *path;

      int idx;

    };

    template <typename CPath>

    void buildRev(const CPath& path) {

      int len = path.length();

      head.reserve(len);

      for (typename CPath::RevArcIt it(path); it != INVALID; ++it) {

        head.push_back(it);

      }

    }

  protected:

    typedef std::vector<Arc> Container;

    Container head, tail;

  };

  /// \brief A structure for representing directed paths in a digraph.

  ///

  /// A structure for representing directed path in a digraph.

  /// \tparam _Digraph The digraph type in which the path is.

  ///

  /// In a sense, the path can be treated as a list of arcs. The

  /// lemon path type stores just this list. As a consequence it

  /// cannot enumerate the nodes in the path and the zero length paths

  /// cannot store the source.

  ///

  /// This implementation is a just back insertable and erasable path

  /// type. It can be indexed in O(1) time. The back insertion and

  /// erasure is amortized O(1) time. This implementation is faster

  /// then the \c Path type because it use just one vector for the

  /// arcs.

  template <typename _Digraph>

  class SimplePath {

  public:

    typedef _Digraph Digraph;

    typedef typename Digraph::Arc Arc;

    /// \brief Default constructor

    ///

    /// Default constructor

    SimplePath() {}

    /// \brief Template copy constructor

    ///

    /// This path can be initialized with any other path type. It just

    /// makes a copy of the given path.

    template <typename CPath>

    SimplePath(const CPath& cpath) {

    }

    /// \brief Template copy assignment

    ///

    /// This path can be initialized with any other path type. It just

    /// makes a copy of the given path.

    template <typename CPath>

    SimplePath& operator=(const CPath& cpath) {

      return *this;

    }

    /// \brief Iterator class to iterate on the arcs of the paths

    ///

    /// This class is used to iterate on the arcs of the paths

    ///

    /// Of course it converts to Digraph::Arc

    class ArcIt {

      friend class SimplePath;

    public:

      /// Default constructor

      ArcIt() {}

      /// Invalid constructor

      ArcIt(Invalid) : path(0), idx(-1) {}

      /// \brief Initializate the constructor to the first arc of path

      ArcIt(const SimplePath &_path)

        : path(&_path), idx(_path.empty() ? -1 : 0) {}

    private:

      /// Constructor with starting point

      ArcIt(const SimplePath &_path, int _idx)

        : idx(_idx), path(&_path) {}

    public:

      ///Conversion to Digraph::Arc

      operator const Arc&() const {

        return path->nth(idx);

      }

      /// Next arc

      ArcIt& operator++() {

        ++idx;

        if (idx >= path->length()) idx = -1;

        return *this;

      }

      /// Comparison operator

      bool operator==(const ArcIt& e) const { return idx==e.idx; }

      /// Comparison operator

      bool operator!=(const ArcIt& e) const { return idx!=e.idx; }

      /// Comparison operator

      bool operator<(const ArcIt& e) const { return idx<e.idx; }

    private:

      const SimplePath *path;

  /// \brief A structure for representing directed paths in a digraph.

  ///

  /// A structure for representing directed path in a digraph.

  /// \tparam _Digraph The digraph type in which the path is.

  ///

  /// In a sense, the path can be treated as a list of arcs. The

  /// lemon path type stores just this list. As a consequence it

  /// cannot enumerate the nodes in the path and the zero length paths

  /// cannot store the source.

  ///

  /// This implementation is a back and front insertable and erasable

  /// path type. It can be indexed in O(k) time, where k is the rank

  /// of the arc in the path. The length can be computed in O(n)

  /// time. The front and back insertion and erasure is O(1) time

  /// and it can be splited and spliced in O(1) time.

  template <typename _Digraph>

  class ListPath {

  public:

    typedef _Digraph Digraph;

    typedef typename Digraph::Arc Arc;

  protected:

    // the std::list<> is incompatible

    // hard to create invalid iterator

    struct Node {

      Arc arc;

      Node *next, *prev;

    };

    Node *first, *last;

    std::allocator<Node> alloc;

  public:

    /// \brief Default constructor

    ///

    /// Default constructor

    ListPath() : first(0), last(0) {}

    /// \brief Template copy constructor

    ///

    /// This path can be initialized with any other path type. It just

    /// makes a copy of the given path.

    template <typename CPath>

    ListPath(const CPath& cpath) : first(0), last(0) {

    }

    /// \brief Destructor of the path

    ///

    /// Destructor of the path

    ~ListPath() {

      clear();

    }

    /// \brief Template copy assignment

    ///

    /// This path can be initialized with any other path type. It just

    /// makes a copy of the given path.

    template <typename CPath>

    ListPath& operator=(const CPath& cpath) {

      return *this;

    }

    /// \brief Iterator class to iterate on the arcs of the paths

    ///

    /// This class is used to iterate on the arcs of the paths

    ///

    /// Of course it converts to Digraph::Arc

    class ArcIt {

      friend class ListPath;

    public:

      /// Default constructor

      ArcIt() {}

      /// Invalid constructor

      ArcIt(Invalid) : path(0), node(0) {}

      /// \brief Initializate the constructor to the first arc of path

      ArcIt(const ListPath &_path)

        : path(&_path), node(_path.first) {}

    protected:

      ArcIt(const ListPath &_path, Node *_node)

        : path(&_path), node(_node) {}

    public:

      ///Conversion to Digraph::Arc

      operator const Arc&() const {

        return node->arc;

      }

      /// Next arc

      ArcIt& operator++() {

        node = node->next;

        return *this;

      }

      /// Comparison operator

      bool operator==(const ArcIt& e) const { return node==e.node; }

      /// Comparison operator

      bool operator!=(const ArcIt& e) const { return node!=e.node; }

      /// Comparison operator

      bool operator<(const ArcIt& e) const { return node<e.node; }

    private:

      const ListPath *path;

      Node *node;

      for (typename CPath::ArcIt it(path); it != INVALID; ++it) {

        addBack(it);

      }

    }

    template <typename CPath>

    void buildRev(const CPath& path) {

      for (typename CPath::RevArcIt it(path); it != INVALID; ++it) {

        addFront(it);

      }

    }

  };

  /// \brief A structure for representing directed paths in a digraph.

  ///

  /// A structure for representing directed path in a digraph.

  /// \tparam _Digraph The digraph type in which the path is.

  ///

  /// In a sense, the path can be treated as a list of arcs. The

  /// lemon path type stores just this list. As a consequence it

  /// cannot enumerate the nodes in the path and the source node of

  /// a zero length path is undefined.

  ///

  /// This implementation is completly static, i.e. it can be copy constucted

  /// or copy assigned from another path, but otherwise it cannot be

  /// modified.

  ///

  /// Being the the most memory efficient path type in LEMON,

  /// it is intented to be

  /// used when you want to store a large number of paths.

  template <typename _Digraph>

  class StaticPath {

  public:

    typedef _Digraph Digraph;

    typedef typename Digraph::Arc Arc;

    /// \brief Default constructor

    ///

    /// Default constructor

    StaticPath() : len(0), arcs(0) {}

    /// \brief Template copy constructor

    ///

    /// This path can be initialized from any other path type.

    template <typename CPath>

    StaticPath(const CPath& cpath) : arcs(0) {

    }

    /// \brief Destructor of the path

    ///

    /// Destructor of the path

    ~StaticPath() {

      if (arcs) delete[] arcs;

    }

    /// \brief Template copy assignment

    ///

    /// This path can be made equal to any other path type. It simply

    /// makes a copy of the given path.

    template <typename CPath>

    StaticPath& operator=(const CPath& cpath) {

      return *this;

    }

    /// \brief Iterator class to iterate on the arcs of the paths

    ///

    /// This class is used to iterate on the arcs of the paths

    ///

    /// Of course it converts to Digraph::Arc

    class ArcIt {

      friend class StaticPath;

    public:

      /// Default constructor

      ArcIt() {}

      /// Invalid constructor

      ArcIt(Invalid) : path(0), idx(-1) {}

      /// Initializate the constructor to the first arc of path

      ArcIt(const StaticPath &_path)

        : path(&_path), idx(_path.empty() ? -1 : 0) {}

    private:

      /// Constructor with starting point

      ArcIt(const StaticPath &_path, int _idx)

        : idx(_idx), path(&_path) {}

    public:

      ///Conversion to Digraph::Arc

      operator const Arc&() const {

        return path->nth(idx);

      }

      /// Next arc

      ArcIt& operator++() {

        ++idx;

        if (idx >= path->length()) idx = -1;

        return *this;

      }

      /// Comparison operator

      bool operator==(const ArcIt& e) const { return idx==e.idx; }

      /// Comparison operator

      bool operator!=(const ArcIt& e) const { return idx!=e.idx; }

      /// Comparison operator

      bool operator<(const ArcIt& e) const { return idx<e.idx; }

    private:

      const StaticPath *path;

    template <typename CPath>

    void buildRev(const CPath& path) {

      len = path.length();

      arcs = new Arc[len];

      int index = len;

      for (typename CPath::RevArcIt it(path); it != INVALID; ++it) {

        --index;

        arcs[index] = it;

      }

    }

  private:

    int len;

    Arc* arcs;

  };

  ///////////////////////////////////////////////////////////////////////

  // Additional utilities

  ///////////////////////////////////////////////////////////////////////

  namespace _path_bits {

    template <typename Path, typename Enable = void>

    struct RevPathTagIndicator {

      static const bool value = false;

    };

    template <typename Path>

    struct RevPathTagIndicator<

      Path,

      typename enable_if<typename Path::RevPathTag, void>::type

      > {

      static const bool value = true;

    };

    template <typename Path, typename Enable = void>

    struct BuildTagIndicator {

      static const bool value = false;

    };

    template <typename Path>

    struct BuildTagIndicator<

      Path,

      typename enable_if<typename Path::BuildTag, void>::type

    > {

      static const bool value = true;

    };

    struct PathCopySelectorForward {

        }

      }

    };

      }

    };

    struct PathCopySelectorBackward {

        }

      }

    };

      }

    };

    struct PathCopySelector {

      }      

    };

      }      

    };

  }

  /// \brief Make a copy of a path.

  ///

  }

  /// \brief Check the consistency of a path.

  ///

  /// This function checks that the target of each arc is the same

  /// as the source of the next one.

  ///

  template <typename Digraph, typename Path>

  bool checkPath(const Digraph& digraph, const Path& path) {

    typename Path::ArcIt it(path);

    if (it == INVALID) return true;

    typename Digraph::Node node = digraph.target(it);

    ++it;

    while (it != INVALID) {

      if (digraph.source(it) != node) return false;

      node = digraph.target(it);

      ++it;

    }

    return true;

  }

  /// \brief The source of a path

  ///

  /// This function returns the source node of the given path.

  /// If the path is empty, then it returns \c INVALID.

  template <typename Digraph, typename Path>

  typename Digraph::Node pathSource(const Digraph& digraph, const Path& path) {

    return path.empty() ? INVALID : digraph.source(path.front());

  }

  /// \brief The target of a path

  ///

  /// This function returns the target node of the given path.

  /// If the path is empty, then it returns \c INVALID.

  template <typename Digraph, typename Path>

  typename Digraph::Node pathTarget(const Digraph& digraph, const Path& path) {

    return path.empty() ? INVALID : digraph.target(path.back());

  }

  /// \brief Class which helps to iterate through the nodes of a path

  ///

  /// In a sense, the path can be treated as a list of arcs. The

  /// lemon path type stores only this list. As a consequence, it

  /// cannot enumerate the nodes in the path and the zero length paths

  /// cannot have a source node.

  ///

  /// This class implements the node iterator of a path structure. To

  /// provide this feature, the underlying digraph should be passed to