[RCOM] Receiver

/*Non-Canonical Input Processing*/

#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <fcntl.h>
#include <termios.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>

#define BAUDRATE B38400
#define _POSIX_SOURCE 1 /* POSIX compliant source */
#define MODEMDEVICE "/dev/ttyS"
#define FALSE 0
#define TRUE 1

#define RECEIVER 0
#define TRANSMITTER 1

#define F 0x7e
#define A 0x03
#define S 0x03
#define U 0x07

//volatile int STOP=FALSE;

void main(int argc, char** argv)
{
    int i;
    struct winsize w;

    system ("clear");

    ioctl(STDOUT_FILENO, TIOCGWINSZ, &w);
    //printf ("columns %d\n", w.ws_col);

    for (i = 0; i < w.ws_col / 2 - 7 ; i++)
        printf (" ");
    printf ("Program open.\n");
    printf ("Running llopen...\n");
    //llopen (0, RECEIVER);
}

int llopen(int porta, int flag)
{
    int fd, c, res;
    struct termios oldtio,newtio;
    unsigned char buf;
    char buffer[1], gate[10] = MODEMDEVICE;
    char SET[255];
    unsigned char ua[5];

    /*Open serial port device for reading and writing and not as controlling tty
    because we don't want to get killed if linenoise sends CTRL-C.*/

    sprintf (buffer, "%d", porta);
    strcat (gate, buffer);

    printf ("Gate: %s\n", gate);
    fd = open(gate, O_RDWR | O_NOCTTY);

    if ( tcgetattr(fd,&oldtio) == -1) { /* save current port settings */
      perror("tcgetattr");
      exit(-1);
    }

    bzero(&newtio, sizeof(newtio));
    newtio.c_cflag = BAUDRATE | CS8 | CLOCAL | CREAD;
    newtio.c_iflag = IGNPAR;
    newtio.c_oflag = 0;

    /* set input mode (non-canonical, no echo,...) */
    newtio.c_lflag = 0;

    newtio.c_cc[VTIME]    = 0;   /* inter-character timer unused */
    newtio.c_cc[VMIN]     = 1;   /* blocking read until 1 chars received */


  /*
    VTIME e VMIN devem ser alterados de forma a proteger com um temporizador a
    leitura do(s) próximo(s) caracter(es)
  */



    tcflush(fd, TCIOFLUSH);

    if ( tcsetattr(fd,TCSANOW,&newtio) == -1) {
      perror("tcsetattr");
      exit(-1);
    }

    int aux = 0, state = 0;
    while (state < 5)
    {
        res = read (fd, &buf, 1);
        switch (state)
        {
            case 0:
                if (buf == F)
                {
                    SET[state] = buf;
                    state++;
                }
                break;
            case 1:
                if (buf == A)
                {
                    SET[state] = buf;
                    state++;
                }
                else if (buf != F && buf != A)
                    state--;
                break;
            case 2:
                if (buf == S)
                {
                    SET[state] = buf;
                    state++;
                }
                else if (buf == F)
                    state--;
                else
                    state = 0;
                break;
            case 3:
                if (buf == (A ^ S))
                {
                    SET[state] = buf;
                    state++;
                }
                else if (buf == F)
                    state = 1;
                else
                    state = 0;
                break;
            case 4:
                if (buf == F)
                {
                    SET[state] = buf;
                    state++;
                }
                else
                    state = 0;
                break;
        }
    }

    printf ("Printing SET:\n");
    int i=0;
    for(i; i < state; i++)
        printf("%x", SET[i]);
    printf("\n\n");

    ua[0] = F;
    ua[1] = A;
    ua[2] = U;
    ua[3] = (A ^ U);
    ua[4] = F;

    res = write(fd, ua, 5);
    if (!res)
        printf("Mensagem não enviada.\n");
    else
        printf("%d bytes enviados.\n",res);


    tcsetattr(fd,TCSANOW,&oldtio);
    close(fd);
    return 0;
}

int llread(int fd, char *buffer)
{
    int length = -1;

    fd = open(buffer, O_RDWR | O_NOCTTY);

    return length;
}