text: //
  // detail/posix_fd_set_adapter.hpp
  // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  //
  // Copyright (c) 2003-2018 Christopher M. Kohlhoff (chris at kohlhoff dot com)
  //
  // 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)
  //
  
  #ifndef ASIO_DETAIL_POSIX_FD_SET_ADAPTER_HPP
  #define ASIO_DETAIL_POSIX_FD_SET_ADAPTER_HPP
  
  #if defined(_MSC_VER) && (_MSC_VER >= 1200)
  # pragma once
  #endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
  
  #include "../../../../../asio/asio/include/asio/detail/config.hpp"
  
  #if !defined(ASIO_WINDOWS) \
    && !defined(__CYGWIN__) \
    && !defined(ASIO_WINDOWS_RUNTIME)
  
  #include <cstring>
  #include "../../../../../asio/asio/include/asio/detail/noncopyable.hpp"
  #include "../../../../../asio/asio/include/asio/detail/reactor_op_queue.hpp"
  #include "../../../../../asio/asio/include/asio/detail/socket_types.hpp"
  
  #include "../../../../../asio/asio/include/asio/detail/push_options.hpp"
  
  namespace asio {
  namespace detail {
  
  // Adapts the FD_SET type to meet the Descriptor_Set concept's requirements.
  class posix_fd_set_adapter : noncopyable
  {
  public:
    posix_fd_set_adapter()
      : max_descriptor_(invalid_socket)
    {
      using namespace std; // Needed for memset on Solaris.
      FD_ZERO(&fd_set_);
    }
  
    void reset()
    {
      using namespace std; // Needed for memset on Solaris.
      FD_ZERO(&fd_set_);
    }
  
    bool set(socket_type descriptor)
    {
      if (descriptor < (socket_type)FD_SETSIZE)
      {
        if (max_descriptor_ == invalid_socket || descriptor > max_descriptor_)
          max_descriptor_ = descriptor;
        FD_SET(descriptor, &fd_set_);
        return true;
      }
      return false;
    }
  
    void set(reactor_op_queue<socket_type>& operations, op_queue<operation>& ops)
    {
      reactor_op_queue<socket_type>::iterator i = operations.begin();
      while (i != operations.end())
      {
        reactor_op_queue<socket_type>::iterator op_iter = i++;
        if (!set(op_iter->first))
        {
          asio::error_code ec(error::fd_set_failure);
          operations.cancel_operations(op_iter, ops, ec);
        }
      }
    }
  
    bool is_set(socket_type descriptor) const
    {
      return FD_ISSET(descriptor, &fd_set_) != 0;
    }
  
    operator fd_set*()
    {
      return &fd_set_;
    }
  
    socket_type max_descriptor() const
    {
      return max_descriptor_;
    }
  
    void perform(reactor_op_queue<socket_type>& operations,
        op_queue<operation>& ops) const
    {
      reactor_op_queue<socket_type>::iterator i = operations.begin();
      while (i != operations.end())
      {
        reactor_op_queue<socket_type>::iterator op_iter = i++;
        if (is_set(op_iter->first))
          operations.perform_operations(op_iter, ops);
      }
    }
  
  private:
    mutable fd_set fd_set_;
    socket_type max_descriptor_;
  };
  
  } // namespace detail
  } // namespace asio
  
  #include "../../../../../asio/asio/include/asio/detail/pop_options.hpp"
  
  #endif // !defined(ASIO_WINDOWS)
         // && !defined(__CYGWIN__)
         // && !defined(ASIO_WINDOWS_RUNTIME)
  
  #endif // ASIO_DETAIL_POSIX_FD_SET_ADAPTER_HPP
  