backports.hpp

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/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/*
 * Copyright (c) 2013-2018 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_UTIL_BACKPORTS_HPP
#define NDN_UTIL_BACKPORTS_HPP

#include "../common.hpp"

#ifdef __has_cpp_attribute
#  define NDN_CXX_HAS_CPP_ATTRIBUTE(x) __has_cpp_attribute(x)
#else
#  define NDN_CXX_HAS_CPP_ATTRIBUTE(x) 0
#endif

#ifdef __has_include
#  define NDN_CXX_HAS_INCLUDE(x) __has_include(x)
#else
#  define NDN_CXX_HAS_INCLUDE(x) 0
#endif

#if (__cplusplus > 201402L) && NDN_CXX_HAS_CPP_ATTRIBUTE(fallthrough)
#  define NDN_CXX_FALLTHROUGH [[fallthrough]]
#elif NDN_CXX_HAS_CPP_ATTRIBUTE(clang::fallthrough)
#  define NDN_CXX_FALLTHROUGH [[clang::fallthrough]]
#elif NDN_CXX_HAS_CPP_ATTRIBUTE(gnu::fallthrough)
#  define NDN_CXX_FALLTHROUGH [[gnu::fallthrough]]
#elif defined(__GNUC__) && (__GNUC__ >= 7)
#  define NDN_CXX_FALLTHROUGH __attribute__((fallthrough))
#else
#  define NDN_CXX_FALLTHROUGH ((void)0)
#endif

#include "backports-ostream-joiner.hpp"
#include "nonstd/optional.hpp"

#ifndef NDN_CXX_HAVE_STD_TO_STRING
#include <boost/lexical_cast.hpp>
#endif

namespace ndn {

#ifdef NDN_CXX_HAVE_STD_TO_STRING
using std::to_string;
#else
template<typename V>
inline std::string
to_string(const V& v)
{
  return boost::lexical_cast<std::string>(v);
}
#endif // NDN_CXX_HAVE_STD_TO_STRING

#if __cpp_lib_clamp >= 201603
using std::clamp;
#else
template<typename T, typename Compare>
constexpr const T&
clamp(const T& v, const T& lo, const T& hi, Compare comp)
{
  return comp(v, lo) ? lo : comp(hi, v) ? hi : v;
}

template<typename T>
constexpr const T&
clamp(const T& v, const T& lo, const T& hi)
{
  return (v < lo) ? lo : (hi < v) ? hi : v;
}
#endif // __cpp_lib_clamp

using ::nonstd::optional;
using ::nonstd::bad_optional_access;
using ::nonstd::nullopt;
using ::nonstd::nullopt_t;
using ::nonstd::in_place;
using ::nonstd::in_place_t;
using ::nonstd::make_optional;

} // namespace ndn

#endif // NDN_UTIL_BACKPORTS_HPP