External/module/mqtt_cpp/mqtt/string_view.hpp

// Copyright Takatoshi Kondo 2016
//
// Distributed under the Boost Software License, Version 1.0.
// (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)

#if !defined(MQTT_STRING_VIEW_HPP)
#define MQTT_STRING_VIEW_HPP

#include <iterator>

#include <mqtt/namespace.hpp>

#ifdef MQTT_STD_STRING_VIEW

#include <string_view>

namespace MQTT_NS {

using std::string_view;

using std::basic_string_view;

} // namespace MQTT_NS

#else  // MQTT_STD_STRING_VIEW

#include <boost/version.hpp>

#include <boost/utility/string_view.hpp>
#include <boost/container_hash/hash_fwd.hpp>

namespace MQTT_NS {

using string_view = boost::string_view;

template<class CharT, class Traits = std::char_traits<CharT> >
using basic_string_view = boost::basic_string_view<CharT, Traits>;

} // namespace MQTT_NS

#endif // !defined(MQTT_STD_STRING_VIEW)

namespace MQTT_NS {

namespace detail {

template<class T>
T* to_address(T* p) noexcept
{
    return p;
}

template<class T>
auto to_address(const T& p) noexcept
{
    return detail::to_address(p.operator->());
}

} // namespace detail

// Make a string_view from a pair of iterators.
template<typename Begin, typename End>
string_view make_string_view(Begin begin, End end) {
    return string_view(detail::to_address(begin), static_cast<string_view::size_type>(std::distance(begin, end)));
}

} // namespace MQTT_NS

#endif // MQTT_STRING_VIEW_HPP