buffers

  1 //
  2 // reference_counted.cpp
  3 // ~~~~~~~~~~~~~~~~~~~~~
  4 //
  5 // Copyright (c) 2003-2013 Christopher M. Kohlhoff (chris at kohlhoff dot com)
  6 //
  7 // Distributed under the Boost Software License, Version 1.0. (See accompanying
  8 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
  9 //
 10  
 11 #include <boost/asio.hpp>
 12 #include <boost/bind.hpp>
 13 #include <boost/enable_shared_from_this.hpp>
 14 #include <boost/shared_ptr.hpp>
 15 #include <iostream>
 16 #include <vector>
 17  
 18 using boost::asio::ip::tcp;
 19  
 20 // A reference-counted non-modifiable buffer class.
 21 class shared_const_buffer
 22 {
 23 public:
 24   // Construct from a std::string.
 25   explicit shared_const_buffer(const std::string& data)
 26     : data_(new std::vector<char>(data.begin(), data.end())),
 27       buffer_(boost::asio::buffer(*data_))
 28   {
 29   }
 30  
 31   // Implement the ConstBufferSequence requirements.
 32   typedef boost::asio::const_buffer value_type;
 33   typedef const boost::asio::const_buffer* const_iterator;
 34   const boost::asio::const_buffer* begin() const { return &buffer_; }
 35   const boost::asio::const_buffer* end() const { return &buffer_ + 1; }
 36  
 37 private:
 38   boost::shared_ptr<std::vector<char> > data_;
 39   boost::asio::const_buffer buffer_;
 40 };
 41  
 42 class session
 43   : public boost::enable_shared_from_this<session>
 44 {
 45 public:
 46   session(boost::asio::io_service& io_service)
 47     : socket_(io_service)
 48   {
 49   }
 50  
 51   tcp::socket& socket()
 52   {
 53     return socket_;
 54   }
 55  
 56   void start()
 57   {
 58     using namespace std; // For time_t, time and ctime.
 59     time_t now = time(0);
 60     shared_const_buffer buffer(ctime(&now));
 61     boost::asio::async_write(socket_, buffer,
 62         boost::bind(&session::handle_write, shared_from_this()));
 63   }
 64  
 65   void handle_write()
 66   {
 67   }
 68  
 69 private:
 70   // The socket used to communicate with the client.
 71   tcp::socket socket_;
 72 };
 73  
 74 typedef boost::shared_ptr<session> session_ptr;
 75  
 76 class server
 77 {
 78 public:
 79   server(boost::asio::io_service& io_service, short port)
 80     : io_service_(io_service),
 81       acceptor_(io_service, tcp::endpoint(tcp::v4(), port))
 82   {
 83     session_ptr new_session(new session(io_service_));
 84     acceptor_.async_accept(new_session->socket(),
 85         boost::bind(&server::handle_accept, this, new_session,
 86           boost::asio::placeholders::error));
 87   }
 88  
 89   void handle_accept(session_ptr new_session,
 90       const boost::system::error_code& error)
 91   {
 92     if (!error)
 93     {
 94       new_session->start();
 95     }
 96  
 97     new_session.reset(new session(io_service_));
 98     acceptor_.async_accept(new_session->socket(),
 99         boost::bind(&server::handle_accept, this, new_session,
100           boost::asio::placeholders::error));
101   }
102  
103 private:
104   boost::asio::io_service& io_service_;
105   tcp::acceptor acceptor_;
106 };
107  
108 int main(int argc, char* argv[])
109 {
110   try
111   {
112     if (argc != 2)
113     {
114       std::cerr << "Usage: reference_counted <port>\n";
115       return 1;
116     }
117  
118     boost::asio::io_service io_service;
119  
120     using namespace std; // For atoi.
121     server s(io_service, atoi(argv[1]));
122  
123     io_service.run();
124   }
125   catch (std::exception& e)
126   {
127     std::cerr << "Exception: " << e.what() << "\n";
128   }
129  
130   return 0;
131 }