识别USB端口程序开发感想

程序功能：识别USB设备插在左边的U口还是右边的U口。
准备工作：1.下载资源：因为这个功能设计到驱动级别的编程（本人才疏学浅，可能对这一点的认识有偏差），所以windows自带的
  API中没有实现此功能的函数，需要下载一套新的开发包。大家熟知的是Win_DDK，它里面有我们需要的API，
  这个软件XP版的非常不好下，因为微软是收费的，而且用它开发的人少，我记得当初是在某个ftp服务器上
  下的。
  2.安装Win_DDK，我直接安装在了C：//的路径下。然后在VC中设置
  Tools->Options->Directories中设置Win_DDK的路径，比如C:/WINDDK/2600/INC/WXP
  Project->setting->Link中设置需要的库文件，比如hid.lib setupapi.lib
  库文件的路径我没有设置，直接把需要的.lib文件拷到当前路径下了。
识别USB端口函数的调用过程：


void IdentifyUSB::IdenUSB() 




{...}{


    HANDLE    hHCDev;


    HANDLE    hHubDevice;


    BOOL    success;


    PCHAR    deviceName;


    ULONG   nBytes;


    PCHAR   rootHubName;


    PUSB_NODE_CONNECTION_INFORMATION    connectionInfo;


//------打开HCDx端口，得到它的句柄------


    hHCDev = CreateFile("//./HCD2",        //注意这个形式：/.HCD0。具体原因我就不知道了，呵呵。


                    GENERIC_WRITE,


                    FILE_SHARE_WRITE,


                    NULL,


                    OPEN_EXISTING,


                    0,


                    NULL);


    rootHubName =(char*) GetRootHubName(hHCDev);    //例子中现成的函数，直接拿来用了。




    deviceName = (PCHAR)malloc(strlen(rootHubName) + sizeof("//./"));


    strcpy(deviceName, "//./");


    strcpy(deviceName + sizeof("//./") - 1, rootHubName);


    hHubDevice = CreateFile(deviceName,    //形式大概是/.USB#ROOT_HUB#4&5f8db32&0#{f18a0e88-c30c-11d0-8815-00a0c906bed8}


                    GENERIC_WRITE,


                    FILE_SHARE_WRITE,


                    NULL,


                    OPEN_EXISTING,


                    0,


                    NULL);


    nBytes = sizeof(USB_NODE_CONNECTION_INFORMATION) + sizeof(USB_PIPE_INFO) * 30;              


    connectionInfo = (PUSB_NODE_CONNECTION_INFORMATION)malloc(nBytes);




    connectionInfo->ConnectionIndex = 1;        //查找端口1


//------得到端口1的一些参数------


    success = DeviceIoControl(hHubDevice,        //刚才得到的设备句柄


                      IOCTL_USB_GET_NODE_CONNECTION_INFORMATION,


                      connectionInfo,


                      nBytes,


                      connectionInfo,


                      nBytes,


                      &nBytes,


                      NULL);


    if (connectionInfo->ConnectionStatus == DeviceConnected)    //这里DeviceConnected是头文件中枚举类型




    {...}
fb48
{


        m_Port = RIGHT_PORT;    //连同的是端口1


    }


    else    //查找端口2




    {...}{


//------得到端口2的一些参数------


        connectionInfo->ConnectionIndex = 2;


        success = DeviceIoControl(hHubDevice,


                          IOCTL_USB_GET_NODE_CONNECTION_INFORMATION,


                          connectionInfo,


                          nBytes,


                          connectionInfo,


                          nBytes,


                          &nBytes,


                          NULL);


        if (connectionInfo->ConnectionStatus == DeviceConnected)


        {


            m_Port = LEFT_PORT;


        }            


    }    


    


    CloseHandle(hHubDevice);


    CloseHandle(hHCDev);


}






PCHAR IdentifyUSB::GetRootHubName(HANDLE HostController)




{...}{


    BOOL                success;


    ULONG               nBytes;


    USB_ROOT_HUB_NAME   rootHubName;


    PUSB_ROOT_HUB_NAME  rootHubNameW;


    PCHAR               rootHubNameA;




    rootHubNameW = NULL;


    rootHubNameA = NULL;




   success = DeviceIoControl(HostController,


                              IOCTL_USB_GET_ROOT_HUB_NAME,


                              0,


                              0,


                              &rootHubName,


                              sizeof(rootHubName),


                              &nBytes,


                              NULL);




    if (!success)


    {


        goto GetRootHubNameError;


    }




    nBytes = rootHubName.ActualLength;




    rootHubNameW =(PUSB_ROOT_HUB_NAME) malloc(nBytes);




    if (rootHubNameW == NULL)




    {...}{




        goto GetRootHubNameError;


    }




    success = DeviceIoControl(HostController,


                              IOCTL_USB_GET_ROOT_HUB_NAME,


                              NULL,


                              0,


                              rootHubNameW,


                              nBytes,


                              &nBytes,


                              NULL);




    if (!success)




    {...}{


       goto GetRootHubNameError;


    }




    rootHubNameA = WideStrToMultiStr(rootHubNameW->RootHubName);


    free(rootHubNameW);




    return rootHubNameA;






GetRootHubNameError:


    if (rootHubNameW != NULL)




    {...}{


        free(rootHubNameW);


        rootHubNameW = NULL;


    }




    return NULL;


}




PCHAR IdentifyUSB::WideStrToMultiStr(PWCHAR WideStr)




{...}{


   ULONG nBytes;


    PCHAR MultiStr;


    nBytes = WideCharToMultiByte(


                 CP_ACP,


                 0,


                 WideStr,


                 -1,


                 NULL,


                 0,


                 NULL,


                 NULL);




    if (nBytes == 0)


    {


        return NULL;


    }


    MultiStr =(PCHAR) malloc(nBytes);




    if (MultiStr == NULL)




    {...}{


        return NULL;


    }


    nBytes = WideCharToMultiByte(


                 CP_ACP,


                 0,


                 WideStr,


                 -1,


                 MultiStr,


                 nBytes,


                 NULL,


                 NULL);




    if (nBytes == 0)




    {...}{


        free(MultiStr);


        return NULL;


    }




    return MultiStr;


}