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/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/*
* Copyright (c) 2013-2021 Regents of the University of California.
*
* This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
*
* ndn-cxx library is free software: you can redistribute it and/or modify it under the
* terms of the GNU Lesser General Public License as published by the Free Software
* Foundation, either version 3 of the License, or (at your option) any later version.
*
* ndn-cxx library is distributed in the hope that it will be useful, but WITHOUT ANY
* WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
* PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
*
* You should have received copies of the GNU General Public License and GNU Lesser
* General Public License along with ndn-cxx, e.g., in COPYING.md file. If not, see
* <http://www.gnu.org/licenses/>.
*
* See AUTHORS.md for complete list of ndn-cxx authors and contributors.
*/
#ifndef NDN_CXX_TAG_HPP
#define NDN_CXX_TAG_HPP
namespace ndn {
/**
* @brief Base class for packet tags that can hold any arbitrary information
*/
class Tag
{
public:
virtual
~Tag();
/**
* @fn static constexpr int getTypeId() noexcept
* @return an integer that uniquely identifies this Tag type
* @sa https://redmine.named-data.net/projects/ndn-cxx/wiki/PacketTagTypes
*/
#ifdef DOXYGEN
static constexpr int
getTypeId() noexcept
{
return <type-identifier>;
}
#endif // DOXYGEN
};
inline
Tag::~Tag() = default;
/** @brief provides a tag type for simple types
* @tparam T the value type
* @tparam TypeId the TypeId
*/
template<typename T, int TypeId>
class SimpleTag : public Tag
{
public:
static constexpr int
getTypeId() noexcept
{
return TypeId;
}
/** \brief explicitly convertible from T
*/
constexpr explicit
SimpleTag(const T& value) noexcept
: m_value(value)
{
}
/** \brief implicitly convertible to T
* \return a copy of the enclosed value
*/
operator T() const
{
return m_value;
}
/** \return the enclosed value
*/
constexpr const T&
get() const noexcept
{
return m_value;
}
private:
T m_value;
};
} // namespace ndn
#endif // NDN_CXX_TAG_HPP