//This code is written by Souvik Ghosh
//TCP Client C Program
#include <sys/socket.h>

#include <stdio.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
int main()

{
	int sockfd;
	int len;
	struct sockaddr_in address;
	int result;

	sockfd = socket(AF_INET, SOCK_STREAM, 0);
	address.sin_family = AF_INET;
	address.sin_addr.s_addr = inet_addr("127.0.0.1");
	address.sin_port = 9734;
	len = sizeof(address);
	result = connect(sockfd, (struct sockaddr *)&address, len);
	if(result == -1) {
		perror("not connected!!");
		exit(1);
	}else{
	printf("connected!!\n");
	}
	//user input
	int size;
	int stuffedSize;
	int flag;
printf("please enter the number of bits you want to send: ");
scanf("%d",&size);
int bits[size];
printf("please enter %d bits: ",size);
for(int i=0;i<size;i++){
scanf("%d",&bits[i]);
}
//read and write via sockfd
write(sockfd,&size,sizeof(int));
write(sockfd,&bits,size*sizeof(int));
printf("bits sent\n");
printf("waiting for the server...\n");
//check for stuffing
read(sockfd,&flag,sizeof(int));
if(flag){
    printf("stuffed!!\n");
    }else{
    printf("no need to stuff!!\n");
    }
//size of bits that to be received
read(sockfd,&stuffedSize,sizeof(int));
int stuffedBits[stuffedSize];
//read the bits
read(sockfd,&stuffedBits,sizeof(stuffedBits));
printf("numbers received: ");
int i=0;
for(int i=0;i<stuffedSize;i++){
        printf("%d ",stuffedBits[i]);
    }
printf("\n");
// close the socket connection
close(sockfd);
	exit(0);

}

//This code is written by Souvik Ghosh
//TCP Server C Program
#include <sys/types.h>
#include <sys/socket.h>
#include <stdio.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
/*

struct sockaddr_in {

	short int sin_family; //AF_INET 

	unsigned short int sin_port; //Port number 

	struct in_addr sin_addr; // Internet address 

};


The IP address structure, in_addr, is defined as follows:


struct in_addr {

	unsigned long int s_addr;

};


*/

// Function for bit stuffing
void bitStuffing(int N, int arr[],int brr[],int *len,int *flag)
{
    // Variables to traverse arrays
    int i, j, k;
    i = 0;
    j = 0;
    //check for stuffing
    int check=0;
    // Loop to traverse in the range [0, N)
    while (i < N) {
 
        // If the current bit is 1 and previous bit is 0
        if (arr[i] == 1 && arr[i-1]==0) {
            // Stores the count of consecutive ones
            int count = 0;
            // Loop to check for next 5 bits
            for (k = i; arr[k] == 1 && k < N && count < 5; k++) {
                brr[j] = arr[k];
                j++;
                count++;
                // If 5 consecutive set bits are found insert a 0 bit
                if (count == 5) {
                    brr[j] = 0;
                    check=1;  
                }
                i = k;
            }
        }
 
        // Otherwise insert arr[i] into the array brr[]
        else {
            brr[j] = arr[i];
        }
        i++;
        j++;
    }
    if(check){
    printf("stuffed!!\n");
    }else{
    printf("no need to stuff!!\n");
    }
    *len=j;
    *flag = check;
 
}
int main(){

	int client_sockfd, server_sockfd;
	int server_len, client_len;
	struct sockaddr_in server_address;
	struct sockaddr_in client_address;
	server_sockfd = socket(AF_INET, SOCK_STREAM, 0);
	server_address.sin_family = AF_INET;
	server_address.sin_addr.s_addr = inet_addr("127.0.0.1");
	server_address.sin_port = 9734;
	server_len = sizeof(server_address);
	bind(server_sockfd, (struct sockaddr *)&server_address, server_len);
	listen(server_sockfd, 5);
	printf("Server started.\n");
	while(1) {
		printf("server waiting...\n");
		client_len = sizeof(client_address);
		client_sockfd = accept(server_sockfd,(struct sockaddr *)&client_address, &client_len);
		//read
		int n;
read(client_sockfd,&n,sizeof(int));
int receivedBits[n];
int sentBits[n*2];
int len;
int flag;
read(client_sockfd,&receivedBits,n*sizeof(int));
printf("bits received\n");
//perform operation
printf("performing operation...\n");
bitStuffing(n,receivedBits,sentBits,&len,&flag);
//write
write(client_sockfd,&flag,sizeof(int));
write(client_sockfd,&len,sizeof(int));
write(client_sockfd,&sentBits,len*sizeof(int));
for(int i=0;i<len;i++){
        printf("%d ",sentBits[i]);
    }
printf("\n");
printf("bits sent\n");
// close the socket connection
close(client_sockfd); 
}
return 0;
					
}