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moslab-code/src/l4/pkg/l4re-core/cxx/lib/tl/include/pair
2025-09-12 15:55:45 +02:00

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C++

// vi:set ft=cpp: -*- Mode: C++ -*-
/**
* \file
* \brief Pair implementation
*/
/*
* (c) 2008-2009 Alexander Warg <warg@os.inf.tu-dresden.de>
* economic rights: Technische Universität Dresden (Germany)
*
* License: see LICENSE.spdx (in this directory or the directories above)
*/
#pragma once
#include <l4/cxx/type_traits>
namespace cxx {
/**
* \ingroup cxx_api
* \brief Pair of two values.
*
* Standard container for a pair of values.
* \param First Type of the first value.
* \param Second Type of the second value.
*/
template< typename First, typename Second >
struct Pair
{
/// Type of first value.
typedef First First_type;
/// Type of second value.
typedef Second Second_type;
/// First value.
First first;
/// Second value.
Second second;
/**
* \brief Create a pair from the two values.
* \param first The first value.
* \param second The second value.
*/
template<typename A1, typename A2>
Pair(A1 &&first, A2 &&second)
: first(cxx::forward<A1>(first)), second(cxx::forward<A2>(second)) {}
/**
* \brief Create a pair, default constructing the second value.
* \param first The first value.
*/
template<typename A1>
Pair(A1 &&first)
: first(cxx::forward<A1>(first)), second() {}
/// Default construction.
Pair() = default;
};
template< typename F, typename S >
Pair<F,S> pair(F const &f, S const &s)
{ return cxx::Pair<F,S>(f,s); }
/**
* \brief Comparison functor for Pair.
* \param Cmp Comparison functor for the first value of the pair.
* \param Typ The pair type.
*
* This functor can be used to compare Pair values with respect to the
* first value.
*/
template< typename Cmp, typename Typ >
class Pair_first_compare
{
private:
Cmp const &_cmp;
public:
/**
* \brief Construction.
* \param cmp The comparison functor used for the first value.
*/
Pair_first_compare(Cmp const &cmp = Cmp()) : _cmp(cmp) {}
/**
* \brief Do the comparison based on the first value.
* \param l The lefthand value.
* \param r The righthand value.
*/
bool operator () (Typ const &l, Typ const &r) const
{ return _cmp(l.first,r.first); }
};
}
template< typename OS, typename A, typename B >
inline
OS &operator << (OS &os, cxx::Pair<A,B> const &p)
{
os << p.first << ';' << p.second;
return os;
}