messagewriter.c

labwindow 编程的tcp网络开发例程。

/*---------------------------------------------------------------------------*/
/*                                                                           */
/* FILE:    MessageWriter.c                                                  */
/*                                                                           */
/* PURPOSE: This TCP server shows you how to send data of varying sizes with */
/*          the size encoded in the data.                                    */
/*                                                                           */
/*---------------------------------------------------------------------------*/

/*---------------------------------------------------------------------------*/
/* Include files                                                             */
/*---------------------------------------------------------------------------*/
#include <tcpsupp.h>
#include <ansi_c.h>
#include <cvirte.h>     
#include <userint.h>
#include "MessageWriter.h"

/*---------------------------------------------------------------------------*/
/* Macros                                                                    */
/*---------------------------------------------------------------------------*/
#define tcpChk(f) if ((gTCPError=(f)) < 0) {ReportTCPError(); goto Done;} else

/*---------------------------------------------------------------------------*/
/* Constants                                                                 */
/*---------------------------------------------------------------------------*/
#define SERVER_PORT     ((unsigned int)10000)

/*---------------------------------------------------------------------------*/
/* Global variables                                                          */
/*---------------------------------------------------------------------------*/
static int              gPanel = 0;
static int              gTCPError = 0;
static int              gConnected = 0;
static unsigned int     gConversationHandle;

/*---------------------------------------------------------------------------*/
/* Internal function prototypes                                              */
/*---------------------------------------------------------------------------*/
int CVICALLBACK TCPCallback (unsigned handle, int event, int error, 
                             void *callbackData);
static void ReportTCPError (void);
static void UpdateUserInterface (void);
                             
/*---------------------------------------------------------------------------*/
/* This is the application's entry-point.                                    */
/*---------------------------------------------------------------------------*/
int main (int argc, char *argv[])
{
    int     serverRegistered = 0;
    
    if (InitCVIRTE (0, argv, 0) == 0)
        goto Done;
    
    /* Initialize TCP server. */
    tcpChk (RegisterTCPServer (SERVER_PORT, TCPCallback, NULL));
    serverRegistered = 1;
    
    /* Load and initialize user interface. */
    if ((gPanel = LoadPanel (0, "MessageWriter.uir", PANEL)) < 0)
        goto Done;
    UpdateUserInterface ();
    DisplayPanel (gPanel);
    
    /* Run program. */
    RunUserInterface ();
    
Done:   
    /* Clean up */
    if (gPanel)
        DiscardPanel (gPanel);
    if (serverRegistered)
        UnregisterTCPServer (SERVER_PORT);
    return 0;
}

/*---------------------------------------------------------------------------*/
/* Respond to the panel closure to quit the UI loop.                         */
/*---------------------------------------------------------------------------*/
int CVICALLBACK PanelCallback (int panel, int event, void *callbackData,
        int eventData1, int eventData2)
{
    switch (event)
        {
        case EVENT_CLOSE:
            QuitUserInterface (0);
            break;
        }
    return 0;
}

/*---------------------------------------------------------------------------*/
/* Read the size, generate data, and send it to connected client.            */
/*---------------------------------------------------------------------------*/
int CVICALLBACK SendCallback (int panel, int control, int event,
        void *callbackData, int eventData1, int eventData2)
{
    int     numPoints, dataSize;
    int     *data = NULL;
    int     index;
    int     bytesToWrite, bytesWritten;
    
    switch (event)
        {
        case EVENT_COMMIT:
            /* Get the number of points to write and allocate memory. */
            GetCtrlVal (gPanel, PANEL_NUM_POINTS, &numPoints);
            dataSize = (numPoints + 1) * sizeof (int);
            data = malloc (dataSize);
            if (data == NULL)
                {
                MessagePopup ("Error", "Could not allocate memory for data!");
                goto Done;
                }
                
            /* Set the number of points and generate the data. */
            data[0] = numPoints;
            for (index = 1; index <= numPoints; ++index)
                data[index] = rand() % 100;
                
            /* Send all the data. */
            bytesToWrite = dataSize;
            while (bytesToWrite > 0)
                {
                tcpChk (bytesWritten = ServerTCPWrite (gConversationHandle, 
                    &data[dataSize - bytesToWrite], bytesToWrite, 0));
                bytesToWrite -= bytesWritten;
                }

            /* Display the data. */
            DeleteGraphPlot (gPanel, PANEL_GRAPH, -1, 0);
            PlotY (gPanel, PANEL_GRAPH, &data[1], numPoints, VAL_INTEGER,
                VAL_CONNECTED_POINTS, VAL_EMPTY_SQUARE, 
                VAL_SOLID, 1, VAL_YELLOW);
            
            break;
        }
        
Done:
    free (data);
    return 0;
}

/*---------------------------------------------------------------------------*/
/* Handle incoming and dropped TCP connections.                              */
/*---------------------------------------------------------------------------*/
int CVICALLBACK TCPCallback (unsigned handle, int event, int error, 
                             void *callbackData)
{
    switch (event)
        {
        case TCP_CONNECT:
            if (gConnected)
                {
                /* We already have one client; don't accept another. */
                tcpChk (DisconnectTCPClient (handle));
                }
            else
                {
                /* Handle this new client connection */
                gConversationHandle = handle;
                /*
                 * Set the disconect mode, so we do not need to close 
                 * the connection ourselves.
                 */
                tcpChk (SetTCPDisconnectMode (gConversationHandle, 
                    TCP_DISCONNECT_AUTO));
                gConnected = 1;
                UpdateUserInterface ();
                }
            break;
        case TCP_DATAREADY:
            /* Ignore data sent to the writer. */
            break;
        case TCP_DISCONNECT:
            if (handle == gConversationHandle)
                {
                /* The client we were talking to has disconnected. */
                gConnected = 0;
                UpdateUserInterface ();
                }
            break;
    }

Done:    
    return 0;
}

/*---------------------------------------------------------------------------*/
/* Report TCP Errors.                                                        */
/*---------------------------------------------------------------------------*/
static void ReportTCPError (void)
{
    char    messageBuffer[1024];

    if (gTCPError < 0)
        {
        sprintf(messageBuffer, 
            "TCP library error message: %s\nSystem error message: %s", 
            GetTCPErrorString (gTCPError), GetTCPSystemErrorString());
        MessagePopup ("Error", messageBuffer);
        gTCPError = 0;
        }
}

/*---------------------------------------------------------------------------*/
/* Update user interface dimming.                                            */
/*---------------------------------------------------------------------------*/
static void UpdateUserInterface (void)
{
    DeleteGraphPlot (gPanel, PANEL_GRAPH, -1, 1);
    SetCtrlAttribute (gPanel, PANEL_SEND, ATTR_DIMMED, !gConnected);
    SetCtrlAttribute (gPanel, PANEL_NUM_POINTS, ATTR_DIMMED, !gConnected);
}

/*---------------------------------------------------------------------------*/