pair.hpp

/*
 * Copyright 2020, Intel Corporation
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 * modification, are permitted provided that the following conditions
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 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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 */
 
#ifndef LIBPMEMOBJ_PAIR_HPP
#define LIBPMEMOBJ_PAIR_HPP
 
#include <utility>
 
#include <libpmemobj++/detail/integer_sequence.hpp>
 
namespace pmem
{
 
namespace detail
{
 
template <typename F, typename S>
struct pair {
    constexpr pair() : first(), second()
    {
    }
 
    template <typename... Args1, typename... Args2>
    pair(std::piecewise_construct_t pc, std::tuple<Args1...> first_args,
         std::tuple<Args2...> second_args)
        : pair(pc, first_args, second_args,
           typename make_index_sequence<Args1...>::type{},
           typename make_index_sequence<Args2...>::type{})
    {
    }
 
    constexpr pair(const F &k, const S &v) : first(k), second(v)
    {
    }
 
    template <typename K, typename V>
    constexpr pair(K &&k, V &&v)
        : first(std::forward<K>(k)), second(std::forward<V>(v))
    {
    }
 
    template <typename K, typename V>
    constexpr pair(const std::pair<K, V> &p)
        : first(p.first), second(p.second)
    {
    }
 
    template <typename K, typename V>
    constexpr pair(std::pair<K, V> &&p)
        : first(std::forward<K>(p.first)), second(std::forward<V>(p.second))
    {
    }
 
    F first;
    S second;
 
private:
    template <typename... Args1, typename... Args2, size_t... I1,
          size_t... I2>
    pair(std::piecewise_construct_t, std::tuple<Args1...> &first_args,
         std::tuple<Args2...> &second_args, index_sequence<I1...>,
         index_sequence<I2...>)
        : first(std::forward<Args1>(std::get<I1>(first_args))...),
          second(std::forward<Args2>(std::get<I2>(second_args))...)
    {
    }
};
 
} /* namespace detail */
 
} /* namespace pmem */
 
#endif /* LIBPMEMOBJ_PAIR_HPP */