#include <stdio.h>#include <stdlib.h>#include <string.h>#include <errno.h>#include <netdb.h>#include <unistd.h>#include <ctype.h>#include <sys/types.h>#include <sys/socket.h>#include <netinet/in.h>#include <arpa/inet.h>#include <assert.h>#include <iostream>using namespace std;#include "connection.h"connection::connection(){	socket_descriptor = 0;	readed_bytes = -4;}void connection::connect_to(const char *ip, int port){	sockaddr_in server;	server.sin_family = PF_INET;	server.sin_port = htons(port);	server.sin_addr.s_addr = inet_addr(ip);	bzero(&(server.sin_zero), 8);	assert ((socket_descriptor = socket(PF_INET, SOCK_STREAM, 0)) !=-1);	assert ( connect(socket_descriptor, (struct sockaddr *) & server, 				sizeof(sockaddr_in)) != -1);}void connection::disconnect(){	close(socket_descriptor);}void connection::send( const string &message ){	assert(! message.empty() );	unsigned int len = htonl( message.size() );	string strPrefix( (const char*)&len, 4 );	string str = strPrefix + message;	write( socket_descriptor, str.data(), str.size() );}void connection::receive( string &message ){	while(readed_bytes<0)	{		select_input();		int t=readed_bytes;		readed_bytes += read(socket_descriptor, buffer+readed_bytes+4, 			sizeof(buffer) - readed_bytes - 4);		assert(t!=readed_bytes);	}	int msg_length = ntohl(*(int*)buffer);	while (readed_bytes < msg_length)	{		select_input();		int t=readed_bytes;		readed_bytes += read(socket_descriptor, buffer+readed_bytes+4, 			sizeof(buffer) - readed_bytes - 4);		assert(t!=readed_bytes);	}	buffer[readed_bytes+4] = 0;//Next message lenght must be lower than 2^24	message = string(buffer+4);	for(int i=0;i<readed_bytes-msg_length;i++)		buffer[i]=buffer[i+msg_length+4];	readed_bytes = readed_bytes - msg_length - 4;}void connection::select_input(){	fd_set readFDS;	FD_ZERO( &readFDS );	FD_SET( socket_descriptor, &readFDS );	assert( select( socket_descriptor + 1, &readFDS, 0, 0, 0 ) > 0 );}