// This code is written by SOUVIK GHOSH & DEBMITRA CHATTERJEE
// Client side implementation of UDP client-server model
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#define PORT 8080
#define MAXLINE 1024
// Driver code
int main() 
{
      	int sockfd;
      	char buffer[MAXLINE];
      	struct sockaddr_in servaddr;
// Creating socket file descriptor
      	if ( (sockfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0 ) 
      	{
         	perror("socket creation failed!!!");
         	exit(EXIT_FAILURE);
      	}
      	memset(&servaddr, 0, sizeof(servaddr));
// Filling server information
      	servaddr.sin_family = AF_INET;
      	servaddr.sin_port = htons(PORT);
      	servaddr.sin_addr.s_addr = INADDR_ANY;
      	printf("connected!!\n");
// take data from the user
      	int n=4;
/*printf("Please enter the size of Dataword: ");
	scanf("%d",&n);*/
	    int arr[n];
	    printf("Please enter the %d size Dataword: ",n);
	    for (int i = 0; i <n; i++) 
        {
	      	scanf("%d",&arr[i]);
	    }
// send data
      	sendto(sockfd,&n,sizeof(int),MSG_CONFIRM, (const struct sockaddr *) &servaddr,sizeof(servaddr));
      	sendto(sockfd,&arr,n*sizeof(int),MSG_CONFIRM, (const struct sockaddr *) &servaddr,sizeof(servaddr));
      	printf("data sent...\n");
      	printf("waiting for the server...\n");
// receive data
     	int size,len;
     	recvfrom(sockfd,&size,sizeof(int),MSG_WAITALL, (struct sockaddr *) &servaddr, &len);
     	int receivedBits[size];
     	recvfrom(sockfd,&receivedBits,size*sizeof(int),MSG_WAITALL, (struct sockaddr *) &servaddr, &len);
     	printf("data received...\n");
// display received data
     	for(int i=0;i<size;i++)
     	{
        	printf("%d ",receivedBits[i]);
     	}
     	printf("\n");
     	close(sockfd);
     	return 0;
}

// This code is written by SOUVIK GHOSH & DEBMITRA CHATTERJEE
// Server side implementation of UDP client-server model
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <math.h>
#define PORT 8080
#define MAXLINE 1024
/*********************************************Functions for Hamming code ******************************************************************************/
void hammingCalculation(int data[],int hammingCode[])
{
             	hammingCode[0]=data[0];
             	hammingCode[1]=data[1];
             	hammingCode[2]=data[2];
             	hammingCode[4]=data[3];
            	hammingCode[3]=data[0]^data[1]^data[2];
	            hammingCode[5]=data[0]^data[1]^hammingCode[4];  //data3
	            hammingCode[6]=data[0]^data[2]^hammingCode[4]; //data3
	     	printf("the encoded bits are: ");
	    	for (int i=0;i<7;i++) 
    		{
				printf("%d ",hammingCode[i]);
	  		}
			printf("\n");
}
/****************************************************************************************************************************************************/
// main function
int main() 
{
			int sockfd;
			struct sockaddr_in servaddr, cliaddr;
// Creating socket file descriptor
			if ( (sockfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0 ) 
   			{
   				perror("socket creation failed!!");
   				exit(EXIT_FAILURE);
   			}
			memset(&servaddr, 0, sizeof(servaddr));
			memset(&cliaddr, 0, sizeof(cliaddr));
// Filling server information
			servaddr.sin_family = AF_INET; // IPv4
			servaddr.sin_addr.s_addr = INADDR_ANY;
			servaddr.sin_port = htons(PORT);
// Bind the socket with the server address
			if ( bind(sockfd, (const struct sockaddr *)&servaddr,sizeof(servaddr)) < 0 )
   			{
   			    perror("bind failed!!");
   			    exit(EXIT_FAILURE);
   			}
			printf("server waiting...\n");
			int len;
			len = sizeof(cliaddr); //len is value/result
//receive data from client
			int size;
			recvfrom(sockfd,&size,sizeof(int),MSG_WAITALL, (struct sockaddr *) &servaddr, &len);
			int receivedBits[size];
			int sentBits[7];
			int sizeofCode=7;
			recvfrom(sockfd,&receivedBits,size*sizeof(int),MSG_WAITALL, (struct sockaddr *) &servaddr,&len);
			printf("data received...\n");
// perform operation
// call the hamming calculation function
			printf("performing operation...\n");
			hammingCalculation(receivedBits,sentBits);
//send data to client
			sendto(sockfd,&sizeofCode,sizeof(int),MSG_CONFIRM, (const struct sockaddr *) &servaddr,sizeof(servaddr));
			sendto(sockfd,&sentBits,sizeofCode*sizeof(int),MSG_CONFIRM, (const struct sockaddr *) &servaddr,sizeof(servaddr));
			printf("data sent...\n");
			return 0;
}