.. _cpp-util:

**********************************************************
util.hpp
**********************************************************

Full path: ``graph_canon/util.hpp``

.. default-domain:: cpp
.. default-role:: cpp:expr

.. cpp:namespace:: graph_canon

.. class:: always_true

    A function object always returning `true`.

    .. function:: template<typename ...T> \
                  bool operator()(T&&... args) const

        :returns: `true`
.. class:: always_false

    A function object always returning `false`.

    .. function:: template<typename ...T> \
                  bool operator()(T&&... args) const

        :returns: `false`
.. class:: template<typename Iter> \
           range : std::pair<Iter, Iter>

A class for adapting a pair of iterators into a range, e.g., useful when using Boost.Graph.
See :cpp:expr:`as_range`.

.. cpp:function:: template<typename Iter> \
                  range<Iter> as_range(const std::pair<Iter, Iter> &x)

:returns: :cpp:expr:`range<Iter>(x)`

.. class:: template<typename Prop> \
           property_less

    A less-than comparator on a given property map, satisfying the `boost::ReadablePropertyMapConcept`.

    .. function:: property_less(Prop prop)
    .. function:: template<typename Key> \
                  bool operator()(const Key &lhs, const Key &rhs) const

        :returns: `get(prop, lhs) < get(prop, rhs)`
    .. var:: Prop prop
.. function:: template<typename Prop> \
              property_less<Prop> make_property_less(Prop &&prop)

    :returns: `property_less<Prop>(std::forward<Prop>(prop))`
.. function:: template<typename Graph, typename SizeType> \
              void permute_graph(const Graph &g_in, Graph &g_out, const std::vector<SizeType> &permutation)

    Add all vertices and edges from `g_in` to `g_out`,
    but where the order of vertex addition is given by the `permutation`.
    It must be a permutation of the vertex indices of `g_in` and is interpreted as a map
    from the indices in `g_in` to the indices they will get in `g_out` (offset by `num_vertices(g_out)` before the call).