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PostOffice Class Reference

#include <post.h>

List of all members.

Public Methods

 PostOffice (NetworkAddress addr, double reliability, int nBoxes)
 ~PostOffice ()
void Send (PacketHeader pktHdr, MailHeader mailHdr, char *data)
void Receive (int box, PacketHeader *pktHdr, MailHeader *mailHdr, char *data)
void PostalDelivery ()
void PacketSent ()
void IncomingPacket ()

Private Attributes

Network * network
NetworkAddress netAddr
MailBox * boxes
int numBoxes
Semaphore * messageAvailable
Semaphore * messageSent
Lock * sendLock

Constructor & Destructor Documentation

PostOffice::PostOffice (  NetworkAddress    addr,
double    reliability,
int    nBoxes
) 
 

Definition at line 178 of file post.cc.

References boxes, Thread::Fork, messageAvailable, messageSent, netAddr, network, NetworkAddress, numBoxes, PostalHelper, ReadAvail, sendLock, and WriteDone. 

00179 {
00180 // First, initialize the synchronization with the interrupt handlers
00181     messageAvailable = new Semaphore("message available", 0);
00182     messageSent = new Semaphore("message sent", 0);
00183     sendLock = new Lock("message send lock");
00184 
00185 // Second, initialize the mailboxes
00186     netAddr = addr; 
00187     numBoxes = nBoxes;
00188     boxes = new MailBox[nBoxes];
00189 
00190 // Third, initialize the network; tell it which interrupt handlers to call
00191     network = new Network(addr, reliability, ReadAvail, WriteDone, (int) this);
00192 
00193 
00194 // Finally, create a thread whose sole job is to wait for incoming messages,
00195 //   and put them in the right mailbox. 
00196     Thread *t = new Thread("postal worker");
00197 
00198     t->Fork(PostalHelper, (int) this);
00199 }

PostOffice::~PostOffice (    ) 
 

Definition at line 206 of file post.cc.

References boxes, messageAvailable, messageSent, network, and sendLock. 

00207 {
00208     delete network;
00209     delete [] boxes;
00210     delete messageAvailable;
00211     delete messageSent;
00212     delete sendLock;
00213 }

Member Function Documentation

void PostOffice::IncomingPacket (    ) 
 

Definition at line 328 of file post.cc.

References messageAvailable, and Semaphore::V.

Referenced by ReadAvail. 

00329 { 
00330     messageAvailable->V(); 
00331 }

void PostOffice::PacketSent (    ) 
 

Definition at line 344 of file post.cc.

References messageSent, and Semaphore::V.

Referenced by WriteDone. 

00345 { 
00346     messageSent->V();
00347 }

void PostOffice::PostalDelivery (    ) 
 

Definition at line 224 of file post.cc.

References ASSERT, boxes, DebugIsEnabled, MailHeader::length, MaxMailSize, MaxPacketSize, messageAvailable, network, numBoxes, Semaphore::P, PrintHeader, Network::Receive, and MailHeader::to.

Referenced by PostalHelper. 

00225 {
00226     PacketHeader pktHdr;
00227     MailHeader mailHdr;
00228     char *buffer = new char[MaxPacketSize];
00229 
00230     for (;;) {
00231         // first, wait for a message
00232         messageAvailable->P();  
00233         pktHdr = network->Receive(buffer);
00234 
00235         mailHdr = *(MailHeader *)buffer;
00236         if (DebugIsEnabled('n')) {
00237             printf("Putting mail into mailbox: ");
00238             PrintHeader(pktHdr, mailHdr);
00239         }
00240 
00241         // check that arriving message is legal!
00242         ASSERT(0 <= mailHdr.to && mailHdr.to < numBoxes);
00243         ASSERT(mailHdr.length <= MaxMailSize);
00244 
00245         // put into mailbox
00246         boxes[mailHdr.to].Put(pktHdr, mailHdr, buffer + sizeof(MailHeader));
00247     }
00248 }

void PostOffice::Receive (  int    box,
PacketHeader *    pktHdr,
MailHeader *    mailHdr,
char *    data
) 
 

Definition at line 311 of file post.cc.

References ASSERT, boxes, MailBox::Get, MailHeader::length, MaxMailSize, and numBoxes. 

00313 {
00314     ASSERT((box >= 0) && (box < numBoxes));
00315 
00316     boxes[box].Get(pktHdr, mailHdr, data);
00317     ASSERT(mailHdr->length <= MaxMailSize);
00318 }

void PostOffice::Send (  PacketHeader    pktHdr,
MailHeader    mailHdr,
char *    data
) 
 

Definition at line 264 of file post.cc.

References Lock::Acquire, ASSERT, bcopy, DebugIsEnabled, PacketHeader::from, PacketHeader::length, MailHeader::length, MaxMailSize, MaxPacketSize, messageSent, netAddr, network, numBoxes, Semaphore::P, PrintHeader, Lock::Release, Network::Send, sendLock, and MailHeader::to. 

00265 {
00266     char* buffer = new char[MaxPacketSize];     // space to hold concatenated
00267                                                 // mailHdr + data
00268 
00269     if (DebugIsEnabled('n')) {
00270         printf("Post send: ");
00271         PrintHeader(pktHdr, mailHdr);
00272     }
00273     ASSERT(mailHdr.length <= MaxMailSize);
00274     ASSERT(0 <= mailHdr.to && mailHdr.to < numBoxes);
00275     
00276     // fill in pktHdr, for the Network layer
00277     pktHdr.from = netAddr;
00278     pktHdr.length = mailHdr.length + sizeof(MailHeader);
00279 
00280     // concatenate MailHeader and data
00281     bcopy((char *) &mailHdr, buffer, sizeof(MailHeader));
00282     bcopy(data, buffer + sizeof(MailHeader), mailHdr.length);
00283 
00284     sendLock->Acquire();                // only one message can be sent
00285                                         // to the network at any one time
00286     network->Send(pktHdr, buffer);
00287     messageSent->P();                   // wait for interrupt to tell us
00288                                         // ok to send the next message
00289     sendLock->Release();
00290 
00291     delete [] buffer;                   // we've sent the message, so
00292                                         // we can delete our buffer
00293 }

Member Data Documentation

MailBox* PostOffice::boxes [private]
 

Definition at line 134 of file post.h.

Referenced by PostalDelivery, PostOffice, Receive, and ~PostOffice.

Semaphore* PostOffice::messageAvailable [private]
 

Definition at line 136 of file post.h.

Referenced by IncomingPacket, PostalDelivery, PostOffice, and ~PostOffice.

Semaphore* PostOffice::messageSent [private]
 

Definition at line 137 of file post.h.

Referenced by PacketSent, PostOffice, Send, and ~PostOffice.

NetworkAddress PostOffice::netAddr [private]
 

Definition at line 133 of file post.h.

Referenced by PostOffice, and Send.

Network* PostOffice::network [private]
 

Definition at line 132 of file post.h.

Referenced by PostalDelivery, PostOffice, Send, and ~PostOffice.

int PostOffice::numBoxes [private]
 

Definition at line 135 of file post.h.

Referenced by PostalDelivery, PostOffice, Receive, and Send.

Lock* PostOffice::sendLock [private]
 

Definition at line 138 of file post.h.

Referenced by PostOffice, Send, and ~PostOffice.

The documentation for this class was generated from the following files:
Generated on Mon Feb 10 09:54:58 2003 for nachos by doxygen1.2.14 written by Dimitri van Heesch, © 1997-2002
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