ET9_WebGL_Dev/Egametang/Experimental/echo/async_udp_echo_server.cc

//
// async_udp_echo_server.cpp
// ~~~~~~~~~~~~~~~~~~~~~~~~~
//
// Copyright (c) 2003-2010 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)
//

#include <cstdlib>
#include <iostream>
#include <boost/bind.hpp>
#include <boost/asio.hpp>

using boost::asio::ip::udp;

class server
{
public:
	server(boost::asio::io_service& io_service, short port) :
		io_service_(io_service), socket_(io_service, udp::endpoint(udp::v4(),
				port))
	{
		socket_.async_receive_from(boost::asio::buffer(data_, max_length),
				sender_endpoint_, boost::bind(&server::handle_receive_from,
						this, boost::asio::placeholders::error,
						boost::asio::placeholders::bytes_transferred));
	}

	void handle_receive_from(const boost::system::error_code& error,
			size_t bytes_recvd)
	{
		if (!error && bytes_recvd > 0)
		{
			socket_.async_send_to(boost::asio::buffer(data_, bytes_recvd),
					sender_endpoint_, boost::bind(&server::handle_send_to,
							this, boost::asio::placeholders::error,
							boost::asio::placeholders::bytes_transferred));
		}
		else
		{
			socket_.async_receive_from(boost::asio::buffer(data_, max_length),
					sender_endpoint_, boost::bind(&server::handle_receive_from,
							this, boost::asio::placeholders::error,
							boost::asio::placeholders::bytes_transferred));
		}
	}

	void handle_send_to(const boost::system::error_code& /*error*/, size_t /*bytes_sent*/)
	{
		socket_.async_receive_from(boost::asio::buffer(data_, max_length),
				sender_endpoint_, boost::bind(&server::handle_receive_from,
						this, boost::asio::placeholders::error,
						boost::asio::placeholders::bytes_transferred));
	}

private:
	boost::asio::io_service& io_service_;
	udp::socket socket_;
	udp::endpoint sender_endpoint_;
	enum
	{
		max_length = 1024
	};
	char data_[max_length];
};

int main(int argc, char* argv[])
{
	try
	{
		if (argc != 2)
		{
			std::cerr << "Usage: async_udp_echo_server <port>\n";
			return 1;
		}

		boost::asio::io_service io_service;

		using namespace std;
		// For atoi.
		server s(io_service, atoi(argv[1]));

		io_service.run();
	}
	catch (std::exception& e)
	{
		std::cerr << "Exception: " << e.what() << "\n";
	}

	return 0;
}