metric_on_idx.hpp

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//=======================================================================
// Copyright (c) 2013 Piotr Wygocki
//
// Distributed under the Boost Software License, Version 1.0. (See
// accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
//=======================================================================
#ifndef PAAL_METRIC_ON_IDX_HPP
#define PAAL_METRIC_ON_IDX_HPP

#include "paal/data_structures/bimap_traits.hpp"
#include "paal/data_structures/metric/basic_metrics.hpp"

namespace paal {
namespace data_structures {


struct read_values_tag{};
struct read_indexes_tag{};

template <typename Metric, typename Bimap, typename Strategy = read_indexes_tag> class metric_on_idx {
    Metric m_metric;
    Bimap m_idx;
    using btraits = bimap_traits<typename std::decay<Bimap>::type>;

    auto read(typename btraits::Val v, read_values_tag) const -> decltype(m_idx.get_idx(v)) {
        return m_idx.get_idx(v);
    }

    auto read(typename btraits::Idx v, read_indexes_tag) const -> decltype(m_idx.get_val(v)) {
        return m_idx.get_val(v);
    }

    template <typename Vertex>
        auto read(Vertex && v) const -> decltype(this->read(v, Strategy())) {
        return read(v, Strategy{});
    }

  public:

    metric_on_idx(Metric m, Bimap idx)
        : m_metric(m), m_idx(idx) {}

    template <typename Vertex>
    auto operator()(const Vertex & i, const Vertex & j) {
        return m_metric(read(i), read(j));
    }

    template <typename Vertex>
    auto operator()(const Vertex & i, const Vertex & j) const {
        return m_metric(read(i), read(j));
    }
};

template <typename Strategy = read_indexes_tag, typename Metric, typename Bimap>
metric_on_idx<Metric, Bimap, Strategy> make_metric_on_idx(Metric && m,
                                                Bimap && b) {
    return metric_on_idx<Metric, Bimap, Strategy>(std::forward<Metric>(m), std::forward<Bimap>(b));
}


template <typename Metric, typename Bimap>
struct metric_traits<metric_on_idx<Metric, Bimap, read_indexes_tag>> :
public _metric_traits<metric_on_idx<Metric, Bimap, read_indexes_tag>,
       typename bimap_traits<typename std::decay<Bimap>::type>::Idx>
{};

template <typename Metric, typename Bimap>
struct metric_traits<metric_on_idx<Metric, Bimap, read_values_tag>> :
public _metric_traits<metric_on_idx<Metric, Bimap, read_values_tag>,
       typename bimap_traits<typename std::decay<Bimap>::type>::Val>
{};


} 
} 
#endif // PAAL_METRIC_ON_IDX_HPP