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Author: hasnank

src/transmitter.cpp

@@ -43,7 +43,7 @@ void initMESGB();
 void initTimeOut();
 string convMESGBtostr(MESGB m);
 
-/* Child process, receiving XON/XOFF signal from receiver*/
+//child process
 void *childProcess(void *threadid);
 
 int main(int argc, char *argv[]){
@@ -96,7 +96,7 @@ int main(int argc, char *argv[]){
 printf("Menunggu XON...\n");
 usleep(200000);
 }
-else{ //NAKnum != -1
+else{ // !xoff or NAKnum != -1
 if(NAKnum == -1) NAKnum = (lastacked + 1) % NAKnum;
 mesg.msgno = NAKnum;
 mesg.data = cc[NAKnum % RXQSIZE];
@@ -151,6 +151,7 @@ bool corruptACK(char* s){
 }
 return checksum != real_c;
 }
+
 void createSocket(char* addr, char* port){
 //define a client socket
 serv_addr.sin_family = AF_INET;
@@ -162,11 +163,15 @@ void createSocket(char* addr, char* port){
 printf("Membuat socket untuk koneksi ke %s:%d ...\n", receiverAddress, htons(serv_addr.sin_port));
 sockfd = socket(AF_INET, SOCK_DGRAM, 0);
 }
+
+//initialize SOH, STX, and ETX value of frame with defined value SOH, STX, dan ETX
 void initMESGB(){
 mesg.soh = SOH;
 mesg.stx = STX;
 mesg.etx = ETX;
 }
+
+//initialize timeout value
 void initTimeOut(){
 struct timeval tv;
 tv.tv_sec = 3;
@@ -175,6 +180,8 @@ void initTimeOut(){
 perror("Error");
 }
 }
+
+//child process, receiving XON/XOFF and ACK/NAK signal from receiver
 void *childProcess(void *threadid){
 
 int now = 0;
@@ -195,9 +202,8 @@ void *childProcess(void *threadid){
 xoff = true;
 }
 else{
-if(!corruptACK(c_recvfrom)){
-//dia nerima ACK / NAK
-if(c_recvfrom[0] == ACK){
+if(!corruptACK(c_recvfrom)){ //receive ACK/NAK
+if(c_recvfrom[0] == ACK){ //receive ACK
 printf("ACK %d\n", c_recvfrom[1]);
 lastacked = c_recvfrom[1];
 if(lastacked <= lastsent){
@@ -207,17 +213,19 @@ void *childProcess(void *threadid){
 countBuf = lastsent + 1 + (RXQSIZE - 1) - lastacked;
 }
 }
-else{
+else{ //receive NAK
 NAKnum = c_recvfrom[1];
 printf("NAK %d\n", NAKnum);
 }
 }
-else{
+else{ //data corrupted
 puts("CORRUPT!!!!");
 }
 }
 }
 }
+
+//convert frame to string and add checksum value
 string convMESGBtostr(MESGB m){
 string ret = "";
 ret += m.soh;