boost::asio udp异步收发数据_boost asio udp

#ifdef _MSC_VER
#define _WIN32_WINNT 0x0A00
#endif
#include <iostream>
#include <vector>
#include <boost/shared_ptr.hpp>
#include <boost/asio.hpp>
#include <boost/lexical_cast.hpp>
#include <boost/bind.hpp>
#include <boost/function.hpp>
using namespace std;
 
typedef boost::function<void(const boost::system::error_code&, const int&)> Callback;
Callback funcRead_;
Callback funcWrite_;
boost::shared_ptr<boost::asio::io_service> io_service_;
boost::shared_ptr<boost::asio::ip::udp::socket> socket_;
vector<char> bufferRead_;
 
void OnSendData(const boost::system::error_code& ErrorCode, const int& handle)
{
	std::cout << "OnSendData" << std::endl;
 
	if (ErrorCode.value() != 0)
	{
		std::cout << " Error::Sending Data::" << ErrorCode.message() << std::endl;;
	}
}
 
void OnReceiveData(const boost::system::error_code& ErrorCode, const int& handle)
{
	Sleep(100);
	std::cout << "OnReceiveData: " << ErrorCode.value() << " " << socket_->available() << std::endl;
 
	if (ErrorCode.value() == 0)
	{
#if 1
		//socket_->available()会返回TCP/IP协议栈接收缓冲区内字节数，
		//也就是还未从TCP/IP协议栈接收缓冲区拷贝到asio缓冲区的字节数
		if (socket_->available() == 0)
		{
			//此时TCP/IP协议栈接收缓冲区的数据都已经拷贝到asio缓冲区，
			//可以进行业务数据处理
			for (int i = 0; i < bufferRead_.size(); i++)
			{
				std::cout << bufferRead_[i] << " ";
			}
			std::cout << std::endl;
 
			//将asio缓冲区置为null_buffers后，当再有UDP包到来时，
			//数据会存在TCP/IP协议栈接收缓冲区中，并会再次回调函数，
			//并且，socket_->available()会返回TCP/IP协议栈接收缓冲区内字节数
			socket_->async_receive(boost::asio::null_buffers(), funcRead_);
		}
		else
		{
			//当asio缓冲区置为null_buffers时，socket_->available()会返回TCP/IP协议栈接收缓冲区内字节数，
			//这里相当于提供了一个机会重新按照数据包尺寸按需设置asio缓冲区，
			//然后调用async_receive将TCP/IP协议栈接收缓冲区的数据拷贝到asio缓冲区
			//注意：此时async_receive为同步函数，
			//也就是TCP/IP协议栈接收缓冲区的数据会立即拷贝到asio缓冲区
			//然后会会再次回调函数，并且socket_->available()会返回0
			//如果设置了asio的缓冲区，但是大小小于UDP数据包的大小的话，那么多余的数据包将永远丢失
			bufferRead_.resize(socket_->available());
			socket_->async_receive(boost::asio::buffer(bufferRead_, bufferRead_.size()), funcRead_);
 
			//如果在初始化的时候把asio的缓冲区设置为null_buffers，
			//那么也可以在这里进行业务数据处理
			//如果在初始化的时候没有把asio的缓冲区设置为null_buffers，
			//那么这里收不到第一包数据
			for (int i = 0; i < bufferRead_.size(); i++)
			{
				std::cout << bufferRead_[i] << " ";
			}
			std::cout << std::endl;
		}
#endif
 
		//下面这种做法适合数据包大小固定或者永远小于asio缓冲区的情况
#if 0
		for (int i = 0; i < bufferRead_.size(); i++)
		{
			std::cout << bufferRead_[i] << " ";
		}
		std::cout << std::endl;
		socket_->async_receive(boost::asio::buffer(bufferRead_, bufferRead_.size()), funcRead_);
#endif
	}
}
 
void StartReading(int n)
{
	io_service_->run();
}
 
int main()
{
	io_service_ = boost::shared_ptr<boost::asio::io_service>(new boost::asio::io_service);
	socket_ = boost::shared_ptr<boost::asio::ip::udp::socket>(new boost::asio::ip::udp::socket(*io_service_));
	socket_->open(boost::asio::ip::udp::v4());
 
	boost::asio::ip::udp::resolver resolver(*io_service_);
	boost::asio::ip::udp::resolver::query queryA("192.168.1.152", boost::lexical_cast<std::string> (48191));
	boost::asio::ip::udp::resolver::iterator udpEndPoint = resolver.resolve(queryA);
	boost::asio::ip::udp::resolver::query queryB("192.168.1.152", boost::lexical_cast<std::string> (48190));
	boost::asio::ip::udp::resolver::iterator udpLocalPoint = resolver.resolve(queryB);
 
	boost::system::error_code ec;
	boost::asio::ip::udp::socket::reuse_address ra(true);
	socket_->set_option(ra);
	socket_->set_option(boost::asio::socket_base::broadcast(true));
	socket_->bind(*udpLocalPoint);
	socket_->connect(*udpEndPoint, ec);
 
	funcWrite_ = boost::bind(OnSendData, boost::asio::placeholders::error, 0);
	funcRead_ = boost::bind(&OnReceiveData, boost::asio::placeholders::error, 0);
 
	//如果初始化的时候就将asio缓冲区设置为null_buffers，
	//那么业务数据处理在回调函数的socket_->available()两个分支都可以得到处理
	//因为每次会先调用socket_->available() > 0，然后调用socket_->available() == 0
	//如果初始化的时候没有将asio缓冲区设置为null_buffers，
	//那么第一包的业务数据处理只能在socket_->available() == 0的时候处理
	//但是这样作的话，可能会丢失数据，因为不知道缓冲区要设置为多大
	socket_->async_receive(boost::asio::null_buffers(), funcRead_);
	std::thread t(StartReading, NULL);
 
	std::vector<char> sendBuffer_(100);
	while (1)
	{
		std::cin >> &sendBuffer_[0];
		socket_->async_send_to(boost::asio::buffer(sendBuffer_, sendBuffer_.size()), *udpEndPoint, funcWrite_);
	}
}