转：SOCKET编程进阶之Overlapped I\O完成例程模型

SOCKET编程进阶之Overlapped I\O完成例程模型

原文地址:http://blog.csdn.net/echoff/archive/2007/09/23/1797319.aspx

完成例程模型相比与事件通知模型有个很大的优点就是不再受64个消息的限制，一个线程可以同时管理成百上千个socket连接，且保持较高的性能。
完成例程相比与完成端口较为逊色，因为它的性能不能随着系统CPU数量的增长而线程增长，不过在我看来已经很强了，呵呵～！
说白了，这些连接都是由系统来帮你管理的。你只需做的一件事就是：开启一个线程来accept进来的连接，剩下的工作交由系统来处理。而你，则需要提供给系统一个回调函数，发生新的网络事件的时候系统将执行这个函数：
procedure WorkerRoutine( const dwError, cbTransferred : DWORD; const lpOverlapped : LPWSAOVERLAPPED; const dwFlags : DWORD ); stdcall;
然后告诉系统用WorkerRoutine函数处理接收到的数据：
WSARecv( m_socket, @FBuf, 1, dwTemp, dwFlag, @m_overlap, WorkerRoutine );
然后......没有什么然后了，系统什么都给你做了！

#pragma comment(lib,"ws2_32.lib") 
#include <winsock2.h> 
#include <stdio.h> 
#define DATA_BUFSIZE 1024        // 接收缓冲区大小 
#define MAXSESSION 10000        // 最大连接数 
typedef struct _SOCKET_INFORMATION { 
   OVERLAPPED Overlapped; 
   SOCKET Socket; 
   WSABUF DataBuf; 
   DWORD BytesSEND; 
   DWORD BytesRECV; 
} SOCKET_INFORMATION, * LPSOCKET_INFORMATION; 

SOCKET        ListenSocket = INVALID_SOCKET; 
DWORD   Flags = 0;                                                                // WSARecv的参数 
void CALLBACK WorkerRoutine(DWORD Error, DWORD BytesTransferred,LPWSAOVERLAPPED Overlapped, DWORD InFlags); 
DWORD WINAPI AcceptThread(LPVOID lpParameter) 
{ 
        WSADATA wsaData; 
        WSAStartup(MAKEWORD(2,2),&wsaData); 
        ListenSocket = WSASocket(AF_INET,SOCK_STREAM,IPPROTO_TCP,NULL,NULL,WSA_FLAG_OVERLAPPED); 
        SOCKADDR_IN ServerAddr; 
        ServerAddr.sin_family = AF_INET; 
        ServerAddr.sin_addr.S_un.S_addr = htonl(INADDR_ANY); 
        ServerAddr.sin_port = htons(1234); 
        bind(ListenSocket,(LPSOCKADDR)&ServerAddr,sizeof(ServerAddr)); 
        listen(ListenSocket,100); 
        printf("listenning...\n"); 
        SOCKADDR_IN ClientAddr; 
        int addr_length=sizeof(ClientAddr); 
        while (TRUE) 
        { 
                LPSOCKET_INFORMATION  SI = new SOCKET_INFORMATION; 
                if ((SI->Socket = accept(ListenSocket,(SOCKADDR*)&ClientAddr, &addr_length)) != INVALID_SOCKET) 
                { 
                        printf("accept ip:%s port:%d\n",inet_ntoa(ClientAddr.sin_addr),ClientAddr.sin_port); 
                        memset(&SI->Overlapped,0,sizeof(WSAOVERLAPPED)); 
                        SI->DataBuf.buf = new char[DATA_BUFSIZE]; 
                        SI->DataBuf.len = DATA_BUFSIZE; 
                        memset(SI->DataBuf.buf,0,DATA_BUFSIZE); 
                        if(WSARecv(SI->Socket, &SI->DataBuf, 1, &SI->BytesRECV, &Flags, &SI->Overlapped, WorkerRoutine) == SOCKET_ERROR) 
                        { 
                                int err = WSAGetLastError(); 
                                if(WSAGetLastError() != WSA_IO_PENDING) 
                                { 
                                        printf("disconnect\n"); 
                                        closesocket(SI->Socket); 
                                        delete [] SI->DataBuf.buf; 
                                        delete SI; 
                                        continue; 
                                } 
                        } 
                } 
                 
        } 
return FALSE; 
} 
void CALLBACK WorkerRoutine(DWORD Error, DWORD BytesTransferred, LPWSAOVERLAPPED Overlapped, DWORD InFlags) 
{ 
        LPSOCKET_INFORMATION SI = (LPSOCKET_INFORMATION)Overlapped; 
        if (Error != 0 || BytesTransferred == 0) 
        { 
                printf("disconnect\n"); 
                closesocket(SI->Socket); 
                delete [] SI->DataBuf.buf; 
                delete SI; 
                return; 
        } 
        //使用数据 
        printf("call back:%s\n",SI->DataBuf.buf); 
        memset(SI->DataBuf.buf,0,DATA_BUFSIZE); 
         
        if(WSARecv(SI->Socket, &SI->DataBuf, 1, &SI->BytesRECV, &Flags, &SI->Overlapped, WorkerRoutine) == SOCKET_ERROR) 
        { 
                int err = WSAGetLastError(); 
                if(WSAGetLastError() != WSA_IO_PENDING) 
                { 
                        printf("disconnect\n"); 
                        closesocket(SI->Socket); 
                        delete [] SI->DataBuf.buf; 
                        delete SI; 
                        return; 
                } 
        } 
} 
void main()   
{ 
        HANDLE hThreads = CreateThread(NULL, 0, AcceptThread, NULL, NULL, NULL); 
           
        WaitForSingleObject(hThreads,INFINITE); 
        printf("exit\n"); 
        CloseHandle(hThreads); 
} 


本文来自CSDN博客，转载请标明出处：http://blog.csdn.net/andylin02/archive/2008/10/12/3062724.aspx

本文来自CSDN博客，转载请标明出处：http://blog.csdn.net/andylin02/archive/2008/10/12/3062724.aspx