RhodeCode

namespace lemon {

  /// \addtogroup paths

  /// @{

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

  ///

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

  /// \param Digraph The digraph type in which the path is.

  ///

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

  ///

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

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

  template <typename _Digraph>

  class Path {

  public:

    typedef _Digraph Digraph;

    typedef typename Digraph::Arc Arc;

    /// \brief Default constructor

    ///

    /// Default constructor

    Path() {}

    /// \brief Template copy constructor

    ///

    template <typename CPath>

    Path(const CPath& cpath) {

      copyPath(*this, cpath);

    }

    /// \brief Template copy assignment

    ///

    template <typename CPath>

    Path& operator=(const CPath& cpath) {

      copyPath(*this, 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) {}

      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 {

      /// \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;

    };

    /// \brief Length of the path.

    int length() const { return head.size() + tail.size(); }

    bool empty() const { return head.empty() && tail.empty(); }

    void clear() { head.clear(); tail.clear(); }

    ///

    /// \pre n is in the [0..length() - 1] range

    const Arc& nth(int n) const {

      return n < int(head.size()) ? *(head.rbegin() + n) :

        *(tail.begin() + (n - head.size()));

    }

    ///

    /// \pre n is in the [0..length() - 1] range

    ArcIt nthIt(int n) const {

      return ArcIt(*this, n);

    }

    const Arc& front() const {

      return head.empty() ? tail.front() : head.back();

    }

    /// \brief Add a new arc before the current path

    void addFront(const Arc& arc) {

      head.push_back(arc);

    }

    /// \brief Erase the first arc of the path

    void eraseFront() {

      if (!head.empty()) {

        head.pop_back();

      } else {

        head.clear();

        int halfsize = tail.size() / 2;

        head.resize(halfsize);

        std::copy(tail.begin() + 1, tail.begin() + halfsize + 1,

                  head.rbegin());

        std::copy(tail.begin() + halfsize + 1, tail.end(), tail.begin());

        tail.resize(tail.size() - halfsize - 1);

      }

    }

    const Arc& back() const {

      return tail.empty() ? head.front() : tail.back();

    }

    /// \brief Add a new arc behind the current path

    void addBack(const Arc& arc) {

      tail.push_back(arc);

    }

    /// \brief Erase the last arc of the path

    void eraseBack() {

      if (!tail.empty()) {

        tail.pop_back();

      } else {

        int halfsize = head.size() / 2;

        tail.resize(halfsize);

        std::copy(head.begin() + 1, head.begin() + halfsize + 1,

                  tail.rbegin());

        std::copy(head.begin() + halfsize + 1, head.end(), head.begin());

        head.resize(head.size() - halfsize - 1);

      }

    }

    typedef True BuildTag;

    template <typename CPath>

    void build(const CPath& path) {

      int len = path.length();

      tail.reserve(len);

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

        tail.push_back(it);

      }

    }

    template <typename CPath>

      /// 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;

      int idx;

    };

    /// \brief Length of the path.

    int length() const { return data.size(); }

    bool empty() const { return data.empty(); }

    void clear() { data.clear(); }

    ///

    /// \pre n is in the [0..length() - 1] range

    const Arc& nth(int n) const {

      return data[n];

    }

    /// \brief  Initializes arc iterator to point to the nth arc.

    ArcIt nthIt(int n) const {

      return ArcIt(*this, n);

    }

    const Arc& front() const {

      return data.front();

    }

    const Arc& back() const {

      return data.back();

    }

    /// \brief Add a new arc behind the current path.

    void addBack(const Arc& arc) {

      data.push_back(arc);

    }

    /// \brief Erase the last arc of the path

    void eraseBack() {

      data.pop_back();

      /// 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;

    };

    ///

    /// \pre n is in the [0..length() - 1] range

    const Arc& nth(int n) const {

      Node *node = first;

      for (int i = 0; i < n; ++i) {

        node = node->next;

      }

      return node->arc;

    }

    /// \brief Initializes arc iterator to point to the nth arc.

    ArcIt nthIt(int n) const {

      Node *node = first;

    /// \brief Length of the path.

    int length() const {

      int len = 0;

      Node *node = first;

      while (node != 0) {

        node = node->next;

        ++len;

      }

      return len;

    }

    bool empty() const { return first == 0; }

    void clear() {

      while (first != 0) {

        last = first->next;

        alloc.destroy(first);

        alloc.deallocate(first, 1);

        first = last;

      }

    }

    const Arc& front() const {

      return first->arc;

    }

    /// \brief Add a new arc before the current path

    void addFront(const Arc& arc) {

      Node *node = alloc.allocate(1);

      alloc.construct(node, Node());

      node->prev = 0;

      node->next = first;

      node->arc = arc;

      if (first) {

    void eraseFront() {

      Node *node = first;

      first = first->next;

      if (first) {

        first->prev = 0;

      } else {

        last = 0;

      }

      alloc.destroy(node);

      alloc.deallocate(node, 1);

    }

    const Arc& back() const {

      return last->arc;

    }

    /// \brief Add a new arc behind the current path.

    void addBack(const Arc& arc) {

      Node *node = alloc.allocate(1);

      alloc.construct(node, Node());

      node->next = 0;

      node->prev = last;

      node->arc = arc;

      if (last) {

    void eraseBack() {

      Node *node = last;

      last = last->prev;

      if (last) {

        last->next = 0;

      } else {

        first = 0;

      }

      alloc.destroy(node);

      alloc.deallocate(node, 1);

    }

    ///

    /// tpath becomes empty. The time complexity of this function is

    /// O(1).

    void spliceBack(ListPath& tpath) {

      if (first) {

        if (tpath.first) {

          last->next = tpath.first;

          tpath.first->prev = last;

          last = tpath.last;

        }

      } else {

        first = tpath.first;

        last = tpath.last;

      }

      tpath.first = tpath.last = 0;

    }

    ///

    /// becomes empty. The time complexity of this function

    /// is O(1).

    void spliceFront(ListPath& tpath) {

      if (first) {

        if (tpath.first) {

          first->prev = tpath.last;

          tpath.last->next = first;

          first = tpath.first;

        }

      } else {

        first = tpath.first;

        last = tpath.last;

      }

      tpath.first = tpath.last = 0;

    }

    ///

    /// It splices the \c tpath into the current path before the

    /// position of \c it iterator and \c tpath becomes empty. The

    void splice(ArcIt it, ListPath& tpath) {

      if (it.node) {

        if (tpath.first) {

          tpath.first->prev = it.node->prev;

          if (it.node->prev) {

            it.node->prev->next = tpath.first;

          } else {

            first = tpath.first;

          }

          it.node->prev = tpath.last;

          tpath.last->next = it.node;

        }

            last->next = tpath.first;

            tpath.first->prev = last;

            last = tpath.last;

          }

        } else {

          first = tpath.first;

          last = tpath.last;

        }

      }

      tpath.first = tpath.last = 0;

    }

    ///

    void split(ArcIt it, ListPath& tpath) {

      tpath.clear();

      if (it.node) {

        tpath.first = it.node;

        tpath.last = last;

        if (it.node->prev) {

          last = it.node->prev;

          last->next = 0;

        } else {

          first = last = 0;

        }

        it.node->prev = 0;

      }

    }

  };

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

  ///

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

  /// \param 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

  ///

  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

    ///

    template <typename CPath>

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

      copyPath(*this, cpath);

    }

    /// \brief Destructor of the path

    ///

    /// Destructor of the path

    ~StaticPath() {

      if (arcs) delete[] arcs;

    }

    /// \brief Template copy assignment

    ///

    /// makes a copy of the given path.

    template <typename CPath>

    StaticPath& operator=(const CPath& cpath) {

      copyPath(*this, 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

      /// 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;

      int idx;

    };

    ///

    /// \pre n is in the [0..length() - 1] range

    const Arc& nth(int n) const {

      return arcs[n];

    }

    ArcIt nthIt(int n) const {

      return ArcIt(*this, n);

    }

    int length() const { return len; }

    int empty() const { return len == 0; }

    void clear() {

      len = 0;

      if (arcs) delete[] arcs;

      arcs = 0;

    }

    const Arc& front() const {

      return arcs[0];

    }

    const Arc& back() const {

      return arcs[len - 1];

    }

    typedef True BuildTag;

    template <typename CPath>

    void build(const CPath& path) {

      len = path.length();

      arcs = new Arc[len];

      int index = 0;

      Target, Source, 

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

      typename enable_if<typename Source::RevPathTag, void>::type> {

      static void copy(Target& target, const Source& source) {

        target.clear();

        target.buildRev(source);

      }

    };

  }

  ///

  template <typename Target, typename Source>

  void copyPath(Target& target, const Source& source) {

    checkConcept<concepts::PathDumper<typename Source::Digraph>, Source>();

    _path_bits::PathCopySelector<Target, Source>::copy(target, source);

  }

  ///

  /// 

  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;

  }

  ///

  template <typename Digraph, typename Path>

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

    return digraph.source(path.front());

  }

  ///

  template <typename Digraph, typename Path>

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

    return digraph.target(path.back());

  }

  ///

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

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

  ///

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

  /// the constructor of the iterator.

  template <typename Path>

  class PathNodeIt {

  private:

    const typename Path::Digraph *_digraph;

    typename Path::ArcIt _it;

    typename Path::Digraph::Node _nd;

  public:

    typedef typename Path::Digraph Digraph;

    typedef typename Digraph::Node Node;