... | ... |
@@ -994,60 +994,62 @@ |
994 | 994 |
_path_bits::PathCopySelector<Target, Source>::copy(target, source); |
995 | 995 |
} |
996 | 996 |
|
997 | 997 |
/// \brief Check the consistency of a path. |
998 | 998 |
/// |
999 | 999 |
/// This function checks that the target of each arc is the same |
1000 | 1000 |
/// as the source of the next one. |
1001 | 1001 |
/// |
1002 | 1002 |
template <typename Digraph, typename Path> |
1003 | 1003 |
bool checkPath(const Digraph& digraph, const Path& path) { |
1004 | 1004 |
typename Path::ArcIt it(path); |
1005 | 1005 |
if (it == INVALID) return true; |
1006 | 1006 |
typename Digraph::Node node = digraph.target(it); |
1007 | 1007 |
++it; |
1008 | 1008 |
while (it != INVALID) { |
1009 | 1009 |
if (digraph.source(it) != node) return false; |
1010 | 1010 |
node = digraph.target(it); |
1011 | 1011 |
++it; |
1012 | 1012 |
} |
1013 | 1013 |
return true; |
1014 | 1014 |
} |
1015 | 1015 |
|
1016 | 1016 |
/// \brief The source of a path |
1017 | 1017 |
/// |
1018 |
/// This function returns the source of the given path. |
|
1018 |
/// This function returns the source node of the given path. |
|
1019 |
/// If the path is empty, then it returns \c INVALID. |
|
1019 | 1020 |
template <typename Digraph, typename Path> |
1020 | 1021 |
typename Digraph::Node pathSource(const Digraph& digraph, const Path& path) { |
1021 |
return digraph.source(path.front()); |
|
1022 |
return path.empty() ? INVALID : digraph.source(path.front()); |
|
1022 | 1023 |
} |
1023 | 1024 |
|
1024 | 1025 |
/// \brief The target of a path |
1025 | 1026 |
/// |
1026 |
/// This function returns the target of the given path. |
|
1027 |
/// This function returns the target node of the given path. |
|
1028 |
/// If the path is empty, then it returns \c INVALID. |
|
1027 | 1029 |
template <typename Digraph, typename Path> |
1028 | 1030 |
typename Digraph::Node pathTarget(const Digraph& digraph, const Path& path) { |
1029 |
return digraph.target(path.back()); |
|
1031 |
return path.empty() ? INVALID : digraph.target(path.back()); |
|
1030 | 1032 |
} |
1031 | 1033 |
|
1032 | 1034 |
/// \brief Class which helps to iterate through the nodes of a path |
1033 | 1035 |
/// |
1034 | 1036 |
/// In a sense, the path can be treated as a list of arcs. The |
1035 | 1037 |
/// lemon path type stores only this list. As a consequence, it |
1036 | 1038 |
/// cannot enumerate the nodes in the path and the zero length paths |
1037 | 1039 |
/// cannot have a source node. |
1038 | 1040 |
/// |
1039 | 1041 |
/// This class implements the node iterator of a path structure. To |
1040 | 1042 |
/// provide this feature, the underlying digraph should be passed to |
1041 | 1043 |
/// the constructor of the iterator. |
1042 | 1044 |
template <typename Path> |
1043 | 1045 |
class PathNodeIt { |
1044 | 1046 |
private: |
1045 | 1047 |
const typename Path::Digraph *_digraph; |
1046 | 1048 |
typename Path::ArcIt _it; |
1047 | 1049 |
typename Path::Digraph::Node _nd; |
1048 | 1050 |
|
1049 | 1051 |
public: |
1050 | 1052 |
|
1051 | 1053 |
typedef typename Path::Digraph Digraph; |
1052 | 1054 |
typedef typename Digraph::Node Node; |
1053 | 1055 |
|
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