_NETWORKING INTELLIGENT DEVICES_
by Gil Gameiro

Listing One 

typedef struct {
   nuint16   CheckSum;
   nuint16   Length;
   nuint16   ConnectionID;
   nuint16   SequenceNumber;
   nuint16   PacketVersionID;
   nuint16   Reserved;
   nuint16   Function;
   nuint16   SubFunction;
   nuint16   Flags;
   nuint16   Status;

} NPHeader;

/* NPHeader structure is part of every NP packet going on the wire. */

void doNPEspressoMaker(NPConnection *hConn, ECB *reqECB, ECB *replyECB);
{
  /* Get a pointer to the request */
  NPRequestBuffer *stdReq = reqECB->ECB_Fragment[1].FragmentAddress;
  /* Get a pointer to the reply packet */
  NPReplyBuffer *stdReply = replyECB->ECB_Fragment[1].FragmentAddress;
  /* Extract the SubFunction number from the NP Header */
  int replySize = 0;
  int SubFunction = NSwapHiLo16(stReq->Header.SubFunction);
  switch (SubFunction) {
     /* Remotely fake a local control pannel key press */
     case EX_MAKER_FAKE_KEY: {
        /* the key ID to fake is in the first byte */
        nuint8 key = stdReq->DataBuffer[0];
        espressoAddKeyToQueue(key);
        break;
     } 
     /* Remote client is requesting the current status */
     case EX_MAKER_REQUEST_STATUS: {
        memcpy(stdReq->DataBuffer, espressoGetStatus(),
               replySize = SIZEOF_EspressoStatus);
        break;
     }
     /* Display a message on the Maker LCD Display */
     case EX_MAKER_POST_MESSAGE: {
        /* Get NP Lenght field, convert HiLo to Native */
        int msgSize = NSwapHiLo16(reqECB->Header.Length);
        msgSize -= (SIZEOF_NPHeader - 4);
        espressoPostLCD(stdReq->DataBuffer, msgSize);
     }
     /* don't forget to report an error otherwise */
     default: stdReply->Header.Status = NSwapHiLo16(NPER_UNKNOWN_REQUEST);   
  };
  /* Always reply */
  replyECB.ECB_FragmentCount = 2;
  replyECB->ECB_Fragment[1].FragmentLength = replySize + SIZEOF_NPHeader;
}


Listing Two

typedef struct _eventDataBlock {
   struct _eventDataBlock  *edbNext;
   void                    *edbConenction;
   int                      edbFunction;
   int                      edbSubFunction;
   int                      edbStatus;
   int                      edbRequestID;
   long                     edbDataSize;
   nuint8                   edbDataBlock[420];

} EDB;

/* The EDB Structure as defined in the NPCAPI.H file; the DLL API. */

int TMainWindow::sendNP(int subFunction, unsigned char *req, int reqSize, char *reply)
{
  EDB edb;
  memset(&edb, 0, sizeof(edb));
  edb.edbFunction = EX_ESPRESSO_CLASS;
  edb.edbSubFunction = subFunction;
  if (edb.edbDataSize = reqSize)
     memcpy(edb.edbDataBlock, req, reqSize);
  int error = ::NPSendExtendedNP(hConn, &edb);
  // If that request generated a reply, transfer it to the user
  if (!error && edb.edbDataSize && reply)
     // that guy's buffer better be big enough!
     memcpy(reply, edb.edbDataBlock, edb.edbDataSize);
  return error;
}
int TMainWinow::fakeKeyPress(int keyID)
{
  unsigned char key = (unsigned)keyID;
  sendNP(EX_MAKER_FAKE_KEY, &key, 1, NULL);
}



Example 1:

int msgSize = NSwapHiLo16(reqECB->Header.Length);
msgSize -= (SIZEOF_NPHeader - 4);