tag.hpp
Go to the documentation of this file.
1 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
2 /*
3  * Copyright (c) 2013-2022 Regents of the University of California.
4  *
5  * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
6  *
7  * ndn-cxx library is free software: you can redistribute it and/or modify it under the
8  * terms of the GNU Lesser General Public License as published by the Free Software
9  * Foundation, either version 3 of the License, or (at your option) any later version.
10  *
11  * ndn-cxx library is distributed in the hope that it will be useful, but WITHOUT ANY
12  * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
13  * PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
14  *
15  * You should have received copies of the GNU General Public License and GNU Lesser
16  * General Public License along with ndn-cxx, e.g., in COPYING.md file. If not, see
17  * <http://www.gnu.org/licenses/>.
18  *
19  * See AUTHORS.md for complete list of ndn-cxx authors and contributors.
20  */
21 
22 #ifndef NDN_CXX_TAG_HPP
23 #define NDN_CXX_TAG_HPP
24 
25 namespace ndn {
26 
30 class Tag
31 {
32 public:
33  virtual
34  ~Tag() = default;
35 
36 #ifdef DOXYGEN
41  static constexpr int
42  getTypeId() noexcept
43  {
44  return <type-identifier>;
45  }
46 #endif // DOXYGEN
47 };
48 
54 template<typename T, int TypeId>
55 class SimpleTag : public Tag
56 {
57 public:
58  static constexpr int
59  getTypeId() noexcept
60  {
61  return TypeId;
62  }
63 
67  constexpr explicit
68  SimpleTag(const T& value) noexcept
69  : m_value(value)
70  {
71  }
72 
77  operator T() const
78  {
79  return m_value;
80  }
81 
85  constexpr const T&
86  get() const noexcept
87  {
88  return m_value;
89  }
90 
91 private:
92  T m_value;
93 };
94 
95 } // namespace ndn
96 
97 #endif // NDN_CXX_TAG_HPP
Provides a tag type for simple types.
Definition: tag.hpp:56
constexpr SimpleTag(const T &value) noexcept
Explicitly convertible from T.
Definition: tag.hpp:68
static constexpr int getTypeId() noexcept
Definition: tag.hpp:59
constexpr const T & get() const noexcept
Returns the enclosed value.
Definition: tag.hpp:86
Base class for packet tags that can hold any arbitrary information.
Definition: tag.hpp:31
static constexpr int getTypeId() noexcept
Returns an integer that uniquely identifies this Tag type.
Definition: tag.hpp:42
virtual ~Tag()=default
Definition: data.cpp:25