// -*- c++ -*- // ///ingroup datas ///\file ///\brief Class for representing paths in graphs. #ifndef HUGO_PATH_H #define HUGO_PATH_H #include #include #include #include namespace hugo { /// \addtogroup datas /// @{ ///A container for directed paths ///\param Graph The graph type in which the path is. /// ///In a sense, the path can be treated as a graph, for is has \c NodeIt ///and \c EdgeIt with the same usage. These types converts to the \c Node ///and \c Edge of the original graph. ///\todo How to clear a path? ///\todo Clarify the consistency checks to do. template class DirPath { public: typedef typename Graph::Edge GraphEdge; typedef typename Graph::Node GraphNode; class NodeIt; class EdgeIt; protected: const Graph *gr; typedef std::vector Container; Container edges; public: /// Constructor /// \param _G The graph in which the path is. /// DirPath(const Graph &_G) : gr(&_G) {} /// Subpath defined by two nodes. /// \warning It is an error if the two edges are not in order! DirPath(const DirPath &P, const NodeIt &a, const NodeIt &b); /// Subpath defined by two edges. Contains edges in [a,b) /// \warning It is an error if the two edges are not in order! DirPath(const DirPath &P, const EdgeIt &a, const EdgeIt &b); size_t length() const { return edges.size(); } bool empty() const { return edges.empty(); } GraphNode from() const { return empty() ? INVALID : gr->tail(edges[0]); } GraphNode to() const { return empty() ? INVALID : gr->head(edges[length()-1]); } template It& first(It &i) const { return i=It(*this); } template It& nth(It &i, int n) const { return i=It(*this, n); } template bool valid(const It &i) const { return i.valid(); } template It& next(It &e) const { return ++e; } /// \todo ! NodeIt head(const EdgeIt& e) const; NodeIt tail(const EdgeIt& e) const; /*** Iterator classes ***/ class EdgeIt { friend class DirPath; int idx; const DirPath *p; public: EdgeIt() {} EdgeIt(Invalid) : idx(-1), p(0) {} EdgeIt(const DirPath &_p, int _idx = 0) : idx(_idx), p(&_p) { validate(); } bool valid() const { return idx!=-1; } operator GraphEdge () const { return valid() ? p->edges[idx] : INVALID; } EdgeIt& operator++() { ++idx; validate(); return *this; } bool operator==(const EdgeIt& e) const { return idx==e.idx; } bool operator!=(const EdgeIt& e) const { return idx!=e.idx; } bool operator<(const EdgeIt& e) const { return idx= p->length() ) idx=-1; } }; class NodeIt { friend class DirPath; int idx; const DirPath *p; public: NodeIt() {} NodeIt(Invalid) : idx(-1), p(0) {} NodeIt(const DirPath &_p, int _idx = 0) : idx(_idx), p(&_p) { validate(); } bool valid() const { return idx!=-1; } operator const GraphEdge& () const { if(idx >= p->length()) return p->to(); else if(idx >= 0) return p->gr->tail(p->edges[idx]); else return INVALID; } NodeIt& operator++() { ++idx; validate(); return *this; } bool operator==(const NodeIt& e) const { return idx==e.idx; } bool operator!=(const NodeIt& e) const { return idx!=e.idx; } bool operator<(const NodeIt& e) const { return idx p->length() ) idx=-1; } }; friend class Builder; ///Class to build paths ///\ingroup datas ///This class is used to build new paths. ///You can push new edges to the front and to the back of the path in ///arbitrary order the you can commit these changes to the graph. ///\todo We must clarify when the path will be in "transitional" state. class Builder { DirPath &P; Container d; public: ///Constructor ///\param _P the path you want to build. /// Builder(DirPath &_P) : P(_P) {} ///Set the first node of the path. ///Set the first node of the path. ///If the path is empty, this must be call before any call of ///\ref pushFront() or \ref pushBack() void setFirst(const GraphNode &) { } ///Push a new edge to the front of the path ///Push a new edge to the front of the path. ///\sa setFirst() bool pushFront(const GraphEdge& e) { if( empty() || P.gr->head(e)==from() ) { d.push_back(e); return true; } return false; } ///Push a new edge to the back of the path ///Push a new edge to the back of the path. ///\sa setFirst() bool pushBack(const GraphEdge& e) { if( empty() || P.gr->tail(e)==to() ) { P.edges.push_back(e); return true; } return false; } ///Commit the changes to the path. void commit() { if( !d.empty() ) { P.edges.insert(P.edges.begin(), d.rbegin(), d.rend()); d.clear(); } } ///Desctuctor ///The desctuctor. ///It commit also commit the changes. ///\todo Is this what we want? ~Builder() { commit(); } // FIXME: Hmm, pontosan hogy is kene ezt csinalni? // Hogy kenyelmes egy ilyet hasznalni? void reserve(size_t r) { d.reserve(r); P.edges.reserve(P.length()+r); } private: bool empty() { return d.empty() && P.empty(); } GraphNode from() const { if( ! d.empty() ) return P.gr->tail(d[d.size()-1]); else if( ! P.empty() ) return P.gr->tail(P.edges[0]); else return INVALID; } GraphNode to() const { if( ! P.empty() ) return P.gr->head(P.edges[P.length()-1]); else if( ! d.empty() ) return P.gr->head(d[0]); else return INVALID; } }; }; /**********************************************************************/ /* Ennek az allocatorosdinak sokkal jobban utana kene nezni a hasznalata elott. Eleg bonyinak nez ki, ahogyan azokat az STL-ben hasznaljak. */ template class DynamicPath { public: typedef typename Graph::Edge GraphEdge; typedef typename Graph::Node GraphNode; class NodeIt; class EdgeIt; protected: Graph& G; // FIXME: ehelyett eleg lenne tarolni ket boolt: a ket szelso el // iranyitasat: GraphNode _first, _last; typedef std::deque Container; Container edges; public: DynamicPath(Graph &_G) : G(_G), _first(INVALID), _last(INVALID) {} /// Subpath defined by two nodes. /// Nodes may be in reversed order, then /// we contstruct the reversed path. DynamicPath(const DynamicPath &P, const NodeIt &a, const NodeIt &b); /// Subpath defined by two edges. Contains edges in [a,b) /// It is an error if the two edges are not in order! DynamicPath(const DynamicPath &P, const EdgeIt &a, const EdgeIt &b); size_t length() const { return edges.size(); } GraphNode from() const { return _first; } GraphNode to() const { return _last; } NodeIt& first(NodeIt &n) const { return nth(n, 0); } EdgeIt& first(EdgeIt &e) const { return nth(e, 0); } template It first() const { It e; first(e); return e; } NodeIt& nth(NodeIt &, size_t) const; EdgeIt& nth(EdgeIt &, size_t) const; template It nth(size_t n) const { It e; nth(e, n); return e; } bool valid(const NodeIt &n) const { return n.idx <= length(); } bool valid(const EdgeIt &e) const { return e.it < edges.end(); } bool isForward(const EdgeIt &e) const { return e.forw; } /// index of a node on the path. Returns length+2 for the invalid NodeIt int index(const NodeIt &n) const { return n.idx; } /// index of an edge on the path. Returns length+1 for the invalid EdgeIt int index(const EdgeIt &e) const { return e.it - edges.begin(); } EdgeIt& next(EdgeIt &e) const; NodeIt& next(NodeIt &n) const; template It getNext(It it) const { It tmp(it); return next(tmp); } // A path is constructed using the following four functions. // They return false if the requested operation is inconsistent // with the path constructed so far. // If your path has only one edge you MUST set either "from" or "to"! // So you probably SHOULD call it in any case to be safe (and check the // returned value to check if your path is consistent with your idea). bool pushFront(const GraphEdge &e); bool pushBack(const GraphEdge &e); bool setFrom(const GraphNode &n); bool setTo(const GraphNode &n); // WARNING: these two functions return the head/tail of an edge with // respect to the direction of the path! // So G.head(P.graphEdge(e)) == P.graphNode(P.head(e)) holds only if // P.forward(e) is true (or the edge is a loop)! NodeIt head(const EdgeIt& e) const; NodeIt tail(const EdgeIt& e) const; // FIXME: ezeknek valami jobb nev kellene!!! GraphEdge graphEdge(const EdgeIt& e) const; GraphNode graphNode(const NodeIt& n) const; /*** Iterator classes ***/ class EdgeIt { friend class DynamicPath; typename Container::const_iterator it; bool forw; public: // FIXME: jarna neki ilyen is... // EdgeIt(Invalid); bool forward() const { return forw; } bool operator==(const EdgeIt& e) const { return it==e.it; } bool operator!=(const EdgeIt& e) const { return it!=e.it; } bool operator<(const EdgeIt& e) const { return it typename DynamicPath::EdgeIt& DynamicPath::next(DynamicPath::EdgeIt &e) const { if( e.it == edges.end() ) return e; GraphNode common_node = ( e.forw ? G.head(*e.it) : G.tail(*e.it) ); ++e.it; // Invalid edgeit is always forward :) if( e.it == edges.end() ) { e.forw = true; return e; } e.forw = ( G.tail(*e.it) == common_node ); return e; } template typename DynamicPath::NodeIt& DynamicPath::next(NodeIt &n) const { if( n.idx >= length() ) { // FIXME: invalid n.idx = length()+1; return n; } GraphNode next_node = ( n.tail ? G.head(edges[n.idx]) : G.tail(edges[n.idx]) ); ++n.idx; if( n.idx < length() ) { n.tail = ( next_node == G.tail(edges[n.idx]) ); } else { n.tail = true; } return n; } template bool DynamicPath::edgeIncident(const GraphEdge &e, const GraphNode &a, GraphNode &b) { if( G.tail(e) == a ) { b=G.head(e); return true; } if( G.head(e) == a ) { b=G.tail(e); return true; } return false; } template bool DynamicPath::connectTwoEdges(const GraphEdge &e, const GraphEdge &f) { if( edgeIncident(f, G.tail(e), _last) ) { _first = G.head(e); return true; } if( edgeIncident(f, G.head(e), _last) ) { _first = G.tail(e); return true; } return false; } template bool DynamicPath::pushFront(const GraphEdge &e) { if( G.valid(_first) ) { if( edgeIncident(e, _first, _first) ) { edges.push_front(e); return true; } else return false; } else if( length() < 1 || connectTwoEdges(e, edges[0]) ) { edges.push_front(e); return true; } else return false; } template bool DynamicPath::pushBack(const GraphEdge &e) { if( G.valid(_last) ) { if( edgeIncident(e, _last, _last) ) { edges.push_back(e); return true; } else return false; } else if( length() < 1 || connectTwoEdges(edges[0], e) ) { edges.push_back(e); return true; } else return false; } template bool DynamicPath::setFrom(const GraphNode &n) { if( G.valid(_first) ) { return _first == n; } else { if( length() > 0) { if( edgeIncident(edges[0], n, _last) ) { _first = n; return true; } else return false; } else { _first = _last = n; return true; } } } template bool DynamicPath::setTo(const GraphNode &n) { if( G.valid(_last) ) { return _last == n; } else { if( length() > 0) { if( edgeIncident(edges[0], n, _first) ) { _last = n; return true; } else return false; } else { _first = _last = n; return true; } } } template typename DynamicPath::NodeIt DynamicPath::tail(const EdgeIt& e) const { NodeIt n; if( e.it == edges.end() ) { // FIXME: invalid-> invalid n.idx = length() + 1; n.tail = true; return n; } n.idx = e.it-edges.begin(); n.tail = e.forw; return n; } template typename DynamicPath::NodeIt DynamicPath::head(const EdgeIt& e) const { if( e.it == edges.end()-1 ) { return _last; } EdgeIt next_edge = e; next(next_edge); return tail(next_edge); } template typename DynamicPath::GraphEdge DynamicPath::graphEdge(const EdgeIt& e) const { if( e.it != edges.end() ) { return *e.it; } else { return INVALID; } } template typename DynamicPath::GraphNode DynamicPath::graphNode(const NodeIt& n) const { if( n.idx < length() ) { return n.tail ? G.tail(edges[n.idx]) : G.head(edges[n.idx]); } else if( n.idx == length() ) { return _last; } else { return INVALID; } } template typename DynamicPath::EdgeIt& DynamicPath::nth(EdgeIt &e, size_t k) const { if( k<0 || k>=length() ) { // FIXME: invalid EdgeIt e.it = edges.end(); e.forw = true; return e; } e.it = edges.begin()+k; if(k==0) { e.forw = ( G.tail(*e.it) == _first ); } else { e.forw = ( G.tail(*e.it) == G.tail(edges[k-1]) || G.tail(*e.it) == G.head(edges[k-1]) ); } return e; } template typename DynamicPath::NodeIt& DynamicPath::nth(NodeIt &n, size_t k) const { if( k<0 || k>length() ) { // FIXME: invalid NodeIt n.idx = length()+1; n.tail = true; return n; } if( k==length() ) { n.idx = length(); n.tail = true; return n; } n = tail(nth(k)); return n; } // Reszut konstruktorok: template DynamicPath::DynamicPath(const DynamicPath &P, const EdgeIt &a, const EdgeIt &b) : G(P.G), edges(a.it, b.it) // WARNING: if b.it < a.it this will blow up! { if( G.valid(P._first) && a.it < P.edges.end() ) { _first = ( a.forw ? G.tail(*a.it) : G.head(*a.it) ); if( b.it < P.edges.end() ) { _last = ( b.forw ? G.tail(*b.it) : G.head(*b.it) ); } else { _last = P._last; } } } template DynamicPath::DynamicPath(const DynamicPath &P, const NodeIt &a, const NodeIt &b) : G(P.G) { if( !P.valid(a) || !P.valid(b) ) return; int ai = a.idx, bi = b.idx; if( bi