gistfile1.txt

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <dispatch/dispatch.h>
#include <readline/readline.h>
#include <readline/history.h>

bool running = true;
int sockfd, portNum;
struct sockaddr_in serverAddr;
struct hostent *server;
char buffer[1024];

dispatch_source_t readSource;
dispatch_queue_t queue;


bool multiline = false;
static int returnKey(int count, int key) {
	if(!multiline)
		rl_done = 1;
	printf("\n");
}

static int toggleMultiline(int count, int key) {
    if(multiline == false) {
		multiline = true;
		printf("\r~ ");
	} else {
		rl_done = 1;
		printf("\n");
		multiline = false;
	}
}

int main(int argc, char *argv[])
{
	bzero((char *)&serverAddr, sizeof(serverAddr));

	if(argc < 3) {
		fprintf(stderr, "Usage: client <server> <port>\n");
		return 1;
	}

	// Connect to the server
	portNum = atoi(argv[2]);
	sockfd = socket(AF_INET, SOCK_STREAM, 0);
	if(sockfd < 0) {
		fprintf(stderr, "ERROR opening socket\n");
		return 1;
	}
	server = gethostbyname(argv[1]);
	if(server == NULL) {
		fprintf(stderr,"ERROR, no such host\n");
		return 1;
	}
	serverAddr.sin_family = AF_INET;
	bcopy((char *)server->h_addr, (char *)&serverAddr.sin_addr.s_addr, server->h_length);
	serverAddr.sin_port = htons(portNum);
	if(connect(sockfd,(struct sockaddr *) &serverAddr,sizeof(serverAddr)) < 0) {
		fprintf(stderr, "ERROR connecting\n");
		return 1;
	}

	queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0);
	readSource = dispatch_source_create(DISPATCH_SOURCE_TYPE_READ, sockfd, 0, queue);
	dispatch_source_set_event_handler(readSource, ^{
		char buf[1024];
		bzero(buf,sizeof(buf));
		int n = read(sockfd,buf, sizeof(buf)-1);
		if(n < 0)
			fprintf(stderr, "ERROR reading from socket\n");

		// Print the output without messing up the prompt
		int savedPoint = rl_point;
		char *savedLine = rl_copy_text(0, rl_end);
		rl_set_prompt("");
		rl_replace_line("", 0);
		rl_redisplay();
		fprintf(stderr, "\r%s", buf);
		rl_set_prompt("> ");
		rl_replace_line(savedLine, 0);
		rl_point = savedPoint;
		rl_redisplay();
		free(savedLine);
	});
	dispatch_resume(readSource);


	rl_bind_key('\n', returnKey);
	rl_bind_key('\r', returnKey);
	rl_bind_key('\t', toggleMultiline);
	char *line;
	while((line = readline("> ")) != NULL) {
		if(strlen(line) > 0) {
			if(strcmp(line, "q") == 0 || strcmp(line, "quit") == 0)
				break;
			ssize_t n = write(sockfd,line,strlen(line));
			if(n < 0)
				 fprintf(stderr, "ERROR writing to socket");
			add_history(line);
		}
		free(line);
	}

	close(sockfd);
	return 0;
}