313 lines
9.1 KiB
C++
Executable File
313 lines
9.1 KiB
C++
Executable File
/* -*- 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) 2003-2013
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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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///\ingroup concept
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///\file
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///\brief The concept of paths
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///
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#ifndef LEMON_CONCEPTS_PATH_H
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#define LEMON_CONCEPTS_PATH_H
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#include <lemon/core.h>
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#include <lemon/concept_check.h>
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namespace lemon {
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namespace concepts {
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/// \addtogroup concept
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/// @{
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/// \brief A skeleton structure for representing directed paths in
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/// a digraph.
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///
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/// A skeleton structure for representing directed paths in a
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/// digraph.
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/// In a sense, a path can be treated as a list of arcs.
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/// LEMON path types just store this list. As a consequence, they cannot
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/// enumerate the nodes on the path directly and a zero length path
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/// cannot store its source node.
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///
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/// The arcs of a path should be stored in the order of their directions,
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/// i.e. the target node of each arc should be the same as the source
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/// node of the next arc. This consistency could be checked using
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/// \ref checkPath().
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/// The source and target nodes of a (consistent) path can be obtained
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/// using \ref pathSource() and \ref pathTarget().
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///
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/// A path can be constructed from another path of any type using the
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/// copy constructor or the assignment operator.
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///
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/// \tparam GR The digraph type in which the path is.
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template <typename GR>
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class Path {
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public:
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/// Type of the underlying digraph.
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typedef GR Digraph;
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/// Arc type of the underlying digraph.
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typedef typename Digraph::Arc Arc;
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class ArcIt;
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/// \brief Default constructor
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Path() {}
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/// \brief Template copy constructor
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template <typename CPath>
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Path(const CPath& cpath) {}
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/// \brief Template assigment operator
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template <typename CPath>
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Path& operator=(const CPath& cpath) {
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::lemon::ignore_unused_variable_warning(cpath);
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return *this;
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}
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/// Length of the path, i.e. the number of arcs on the path.
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int length() const { return 0;}
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/// Returns whether the path is empty.
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bool empty() const { return true;}
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/// Resets the path to an empty path.
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void clear() {}
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/// \brief LEMON style iterator for enumerating the arcs of a path.
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///
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/// LEMON style iterator class for enumerating the arcs of a path.
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class ArcIt {
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public:
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/// Default constructor
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ArcIt() {}
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/// Invalid constructor
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ArcIt(Invalid) {}
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/// Sets the iterator to the first arc of the given path
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ArcIt(const Path &) {}
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/// Conversion to \c Arc
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operator Arc() const { return INVALID; }
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/// Next arc
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ArcIt& operator++() {return *this;}
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/// Comparison operator
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bool operator==(const ArcIt&) const {return true;}
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/// Comparison operator
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bool operator!=(const ArcIt&) const {return true;}
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/// Comparison operator
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bool operator<(const ArcIt&) const {return false;}
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};
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template <typename _Path>
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struct Constraints {
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void constraints() {
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Path<Digraph> pc;
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_Path p, pp(pc);
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int l = p.length();
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int e = p.empty();
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p.clear();
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p = pc;
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typename _Path::ArcIt id, ii(INVALID), i(p);
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++i;
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typename Digraph::Arc ed = i;
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e = (i == ii);
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e = (i != ii);
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e = (i < ii);
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::lemon::ignore_unused_variable_warning(l);
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::lemon::ignore_unused_variable_warning(pp);
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::lemon::ignore_unused_variable_warning(e);
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::lemon::ignore_unused_variable_warning(id);
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::lemon::ignore_unused_variable_warning(ii);
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::lemon::ignore_unused_variable_warning(ed);
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}
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};
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};
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namespace _path_bits {
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template <typename _Digraph, typename _Path, typename RevPathTag = void>
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struct PathDumperConstraints {
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void constraints() {
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int l = p.length();
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int e = p.empty();
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typename _Path::ArcIt id, i(p);
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++i;
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typename _Digraph::Arc ed = i;
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e = (i == INVALID);
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e = (i != INVALID);
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::lemon::ignore_unused_variable_warning(l);
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::lemon::ignore_unused_variable_warning(e);
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::lemon::ignore_unused_variable_warning(id);
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::lemon::ignore_unused_variable_warning(ed);
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}
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_Path& p;
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PathDumperConstraints() {}
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};
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template <typename _Digraph, typename _Path>
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struct PathDumperConstraints<
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_Digraph, _Path,
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typename enable_if<typename _Path::RevPathTag, void>::type
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> {
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void constraints() {
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int l = p.length();
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int e = p.empty();
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typename _Path::RevArcIt id, i(p);
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++i;
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typename _Digraph::Arc ed = i;
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e = (i == INVALID);
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e = (i != INVALID);
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::lemon::ignore_unused_variable_warning(l);
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::lemon::ignore_unused_variable_warning(e);
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::lemon::ignore_unused_variable_warning(id);
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::lemon::ignore_unused_variable_warning(ed);
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}
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_Path& p;
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PathDumperConstraints() {}
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};
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}
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/// \brief A skeleton structure for path dumpers.
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///
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/// A skeleton structure for path dumpers. The path dumpers are
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/// the generalization of the paths, they can enumerate the arcs
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/// of the path either in forward or in backward order.
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/// These classes are typically not used directly, they are rather
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/// used to be assigned to a real path type.
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///
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/// The main purpose of this concept is that the shortest path
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/// algorithms can enumerate the arcs easily in reverse order.
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/// In LEMON, such algorithms give back a (reverse) path dumper that
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/// can be assigned to a real path. The dumpers can be implemented as
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/// an adaptor class to the predecessor map.
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///
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/// \tparam GR The digraph type in which the path is.
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template <typename GR>
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class PathDumper {
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public:
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/// Type of the underlying digraph.
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typedef GR Digraph;
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/// Arc type of the underlying digraph.
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typedef typename Digraph::Arc Arc;
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/// Length of the path, i.e. the number of arcs on the path.
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int length() const { return 0;}
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/// Returns whether the path is empty.
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bool empty() const { return true;}
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/// \brief Forward or reverse dumping
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///
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/// If this tag is defined to be \c True, then reverse dumping
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/// is provided in the path dumper. In this case, \c RevArcIt
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/// iterator should be implemented instead of \c ArcIt iterator.
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typedef False RevPathTag;
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/// \brief LEMON style iterator for enumerating the arcs of a path.
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///
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/// LEMON style iterator class for enumerating the arcs of a path.
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class ArcIt {
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public:
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/// Default constructor
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ArcIt() {}
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/// Invalid constructor
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ArcIt(Invalid) {}
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/// Sets the iterator to the first arc of the given path
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ArcIt(const PathDumper&) {}
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/// Conversion to \c Arc
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operator Arc() const { return INVALID; }
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/// Next arc
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ArcIt& operator++() {return *this;}
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/// Comparison operator
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bool operator==(const ArcIt&) const {return true;}
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/// Comparison operator
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bool operator!=(const ArcIt&) const {return true;}
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/// Comparison operator
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bool operator<(const ArcIt&) const {return false;}
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};
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/// \brief LEMON style iterator for enumerating the arcs of a path
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/// in reverse direction.
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///
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/// LEMON style iterator class for enumerating the arcs of a path
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/// in reverse direction.
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class RevArcIt {
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public:
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/// Default constructor
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RevArcIt() {}
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/// Invalid constructor
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RevArcIt(Invalid) {}
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/// Sets the iterator to the last arc of the given path
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RevArcIt(const PathDumper &) {}
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/// Conversion to \c Arc
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operator Arc() const { return INVALID; }
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/// Next arc
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RevArcIt& operator++() {return *this;}
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/// Comparison operator
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bool operator==(const RevArcIt&) const {return true;}
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/// Comparison operator
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bool operator!=(const RevArcIt&) const {return true;}
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/// Comparison operator
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bool operator<(const RevArcIt&) const {return false;}
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};
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template <typename _Path>
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struct Constraints {
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void constraints() {
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function_requires<_path_bits::
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PathDumperConstraints<Digraph, _Path> >();
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}
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};
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};
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///@}
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}
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} // namespace lemon
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#endif
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