text: /*
   *             Copyright Andrey Semashev 2019.
   * Distributed under the Boost Software License, Version 1.0.
   *    (See accompanying file LICENSE_1_0.txt or copy at
   *          https://www.boost.org/LICENSE_1_0.txt)
   */
  /*!
   * \file   utility/manipulators/auto_newline.hpp
   * \author Andrey Semashev
   * \date   23.06.2019
   *
   * The header contains implementation of a stream manipulator for inserting a newline, unless there is already one inserted.
   */
  
  #ifndef BOOST_LOG_UTILITY_MANIPULATORS_AUTO_NEWLINE_HPP_INCLUDED_
  #define BOOST_LOG_UTILITY_MANIPULATORS_AUTO_NEWLINE_HPP_INCLUDED_
  
  #include <boost/log/detail/config.hpp>
  #include <boost/log/utility/formatting_ostream_fwd.hpp>
  #include <boost/log/detail/header.hpp>
  
  #ifdef BOOST_HAS_PRAGMA_ONCE
  #pragma once
  #endif
  
  namespace boost {
  
  BOOST_LOG_OPEN_NAMESPACE
  
  /*!
   * Stream manipulator for inserting a newline character, unless the last character
   * inserted into the stream is already a newline.
   */
  struct auto_newline_manip {}
  const auto_newline = {};
  
  /*!
   * Stream output operator for the \c auto_newline manipulator
   */
  template< typename CharT, typename TraitsT, typename AllocatorT >
  inline basic_formatting_ostream< CharT, TraitsT, AllocatorT >& operator<< (basic_formatting_ostream< CharT, TraitsT, AllocatorT >& strm, auto_newline_manip)
  {
      typedef basic_formatting_ostream< CharT, TraitsT, AllocatorT > stream_type;
      typedef typename stream_type::char_type char_type;
      typedef typename stream_type::string_type string_type;
      if (BOOST_LIKELY(strm.good()))
      {
          string_type* str = strm.rdbuf()->storage();
          if (BOOST_LIKELY(!!str))
          {
              strm.rdbuf()->pubsync();
              if (str->empty() || *str->rbegin() != static_cast< char_type >('\n'))
                  strm.rdbuf()->push_back(static_cast< char_type >('\n'));
          }
      }
  
      return strm;
  }
  
  BOOST_LOG_CLOSE_NAMESPACE // namespace log
  
  } // namespace boost
  
  #include <boost/log/detail/footer.hpp>
  
  #endif // BOOST_LOG_UTILITY_MANIPULATORS_AUTO_NEWLINE_HPP_INCLUDED_
  