txc8.cpp

这是一个基于OMNeT++的仿真模型,编程语采用C

//
// This file is part of an OMNeT++/OMNEST simulation example.
//
// Copyright (C) 2003-2005 Andras Varga
//
// This file is distributed WITHOUT ANY WARRANTY. See the file
// `license' for details on this and other legal matters.
//

#include <stdio.h>
#include <string.h>
#include <omnetpp.h>


class Tic8 : public cSimpleModule
{
  private:
    double timeout;  // timeout
    cMessage *timeoutEvent;  // holds pointer to the timeout self-message
    int seq;  // message sequence number
    cMessage *message;  // message that has to be re-sent on timeout

  public:
    Tic8();
    virtual ~Tic8();

  protected:
    virtual cMessage *generateNewMessage();
    virtual void sendCopyOf(cMessage *msg);
    virtual void initialize();
    virtual void handleMessage(cMessage *msg);
};

Define_Module(Tic8);

Tic8::Tic8()
{
    timeoutEvent = message = NULL;
}

Tic8::~Tic8()
{
    cancelAndDelete(timeoutEvent);
    delete message;
}

void Tic8::initialize()
{
    // Initialize variables.
    seq = 0;
    timeout = 1.0;
    timeoutEvent = new cMessage("timeoutEvent");

    // Generate and send initial message.
    ev << "Sending initial message\n";
    message = generateNewMessage();
    sendCopyOf(message);
    scheduleAt(simTime()+timeout, timeoutEvent);
}

void Tic8::handleMessage(cMessage *msg)
{
    if (msg==timeoutEvent)
    {
        // If we receive the timeout event, that means the packet hasn't
        // arrived in time and we have to re-send it.
        ev << "Timeout expired, resending message and restarting timer\n";
        sendCopyOf(message);
        scheduleAt(simTime()+timeout, timeoutEvent);
    }
    else // message arrived
    {
        // Acknowledgement received!
        ev << "Received: " << msg->name() << "\n";
        delete msg;

        // Also delete the stored message and cancel the timeout event.
        ev << "Timer cancelled.\n";
        cancelEvent(timeoutEvent);
        delete message;

        // Ready to send another one.
        message = generateNewMessage();
        sendCopyOf(message);
        scheduleAt(simTime()+timeout, timeoutEvent);
    }
}

cMessage *Tic8::generateNewMessage()
{
    // Generate a message with a different name every time.
    char msgname[20];
    sprintf(msgname, "tic-%d", ++seq);
    cMessage *msg = new cMessage(msgname);
    return msg;
}

void Tic8::sendCopyOf(cMessage *msg)
{
    // Duplicate message and send the copy.
    cMessage *copy = (cMessage *) msg->dup();
    send(copy, "out");
}


class Toc8 : public cSimpleModule
{
  protected:
    virtual void handleMessage(cMessage *msg);
};

Define_Module(Toc8);

void Toc8::handleMessage(cMessage *msg)
{
    if (uniform(0,1) < 0.1)
    {
        ev << "\"Losing\" message " << msg << endl;
        bubble("message lost");
        delete msg;
    }
    else
    {
        ev << msg << " received, sending back an acknowledgement.\n";
        delete msg;
        send(new cMessage("ack"), "out");
    }
}