/*===========================================================================*
 *                               Terminal Task                               *
 *===========================================================================*
 * Written by : Martin Bajgar                                                *
 * Last update: 04-06-1997                                                   *
 *===========================================================================*/
// chybi dodelat volani signalu
/*===========================================================================*
 *                              in_char                                      *
 *===========================================================================*/

/*
 pokud je tty_incount>TTY_IN_BYTES, neni misto, ignoruj
 jde-li zarizeni 2-interruptove, zjisti, ktery to je
 (make_break()) a krome shiftu pusteni ostatnich klaves ignoruj.
 Pri teto prilezitosti se rovnez premapuji scan kody na ASCII
 a udrzuji se globalni priznaky stisku CTRL, ALT, SHIFT,...

 Nejde-li o RAW mode, orez na 7 bitu
 Pro mody COOKED a CBREAK:
  Je-li mod COOKED:
   zpracovani ERASE (neni_li escaped): odstran z fronty posledni znak, echo
   zpracovani KILL (neni_li escaped): zrus posledni radku, echo
   pokud je tty_escaped=NOT_ESCAPED:
    zpracovani \: (\\ znamenaji \, jedno znamena prechod do ESCAPE )
    zpracovani Ctrl-D: znak pro ulozeni do fronty bude MARKER
   jinak:
    nastav tty_escaped=NOT_ESCAPED
    Nejde-li o erase, kill, eof -> pridej do tty_inqueue[] '\'
    (pokud ano, uz se smazalo vyse, nic se nepridava)

  Je-li mod COOKED nebo CBREAK:
  je-li znak \r a tty_mode je CRMOD => prepis na \n
  je-li tty_intr nebo tty_quit: signal SIGINT/SIGQUIT
   v tom pripade take uvolni vystup (tty_inhibited=RUNNING),
   zajisti, ze proces z read() obdrzi EINTR
   Zaregistruj, ze chceme zaslat signal

  Test CTRL-S, CTRL-Q (nastaveni tty_inhibited,
  pri obnovovani volani tty_struct[].tty_devstart())

 Pro vsechny mody:
  jde-li o LF nebo CTRL-D: tty_lfcount++;
  ulozeni znaku do fronty (kruhoveho bufferu), tty_incount++, echo znaku
*/

// incrementace ukazatele na hlavu vsupni fronty
 PRIVATE void inc_inhead(struct tty_struct *tp)
{
 if ((tp->tty_inhead - tp->tty_inqueue) == TTY_IN_BYTES)
  tp->tty_inhead = tp->tty_inqueue;
 else
  tp->tty_inhead++;
}

//dectementace ukazatele na hlavu vstupni fronty
 PRIVATE void dec_inhead(struct tty_struct *tp)
{
 if (tp->tty_inhead == tp->tty_intail)
   return;
 if (tp->tty_inhead == tp->tty_inqueue)
   tp->tty_inhead = tp->tty_inqueue + TTY_IN_BYTES;
 else
   tp->tty_inhead--;
}

PRIVATE in_char(int line /* line # */, unsigned char ch /* scan code */)
{
 struct tty_struct *tp = tty_addr(line);
 char zn, zn1;
 int i;

 if (tp->tty_incount > TTY_IN_BYTES)
  {
    // neni misto ve vstupni fronte
    return 0;
  }

 if ((zn = make_break(ch)) == 0) // zpracovani znaku
    return 0;

 if (tp->tty_discipline == COOKED)
 {
  if (tp->tty_escaped == FALSE)
  {
   if (tp->tty_erase == zn)
    {
     if (tp->tty_incount > 0)
     {
      dec_inhead(tp);
      tp->tty_incount--;
      echo(tp, zn);
     }
     return 1;
    }
   if (tp->tty_kill == zn)
   {
     for (i = 0; i < tp->tty_incount; i++)
     {
      dec_inhead(tp);
      zn1 = *(tp->tty_inhead);
      tp->tty_incount--;

      if (zn1 == '\n')
      {
       tp->tty_lfcount--;
       echo(tp, zn);
       return 1;
      }

      if (tp->tty_incount == 0)
      {
       tp->tty_lfcount = 0;
       echo(tp, zn);
       return 1;
      }
     }
   }
   if (tp->tty_eof == zn)
   {
        *tp->tty_inhead = tp->tty_eof;
        inc_inhead(tp);
        tp->tty_incount++;
        tp->tty_lfcount++;
        return 1;
   }
   if ('/' == zn)
   {
        tp->tty_escaped = TRUE;
        return 1;
   }
  }
 }

 if ((tp->tty_discipline == CBREAK) || (tp->tty_discipline == COOKED))
 {
   /*je-li tty_intr nebo tty_quit: signal SIGINT/SIGQUIT
   v tom pripade take uvolni vystup (tty_inhibited=RUNNING),
   zajisti, ze proces z read() obdrzi EINTR
   Zaregistruj, ze chceme zaslat signal         */

  if ((zn != tp->tty_eof) && (zn != tp->tty_erase) && (zn != tp->tty_kill) && (tp->tty_escaped == TRUE))
   {
    tp->tty_escaped = FALSE;
    *tp->tty_inhead = '\\';
    inc_inhead(tp);
    tp->tty_incount++;
   }

  if ((zn == '\r') && (tp->tty_mode & CRMOD))
     zn = '\n';

  if (zn == tp->tty_intr)
  {
   tp->tty_inhibited = FALSE;
   // SIGINT
   //task_reply(EINTR);
   return 1;
  }

  if (zn == tp->tty_quit)
  {
   tp->tty_inhibited = FALSE;
   //SIGQUIT
   //task_reply(EINTR);
   return 1;
  }

  //Test CTRL-Q (nastaveni tty_inhibited,
  //pri obnovovani volani tty_struct[].tty_devstart())
  if (zn == tp->tty_xon)
  {
   tp->tty_inhibited = FALSE;
   tp->tty_devstart();
   return 1;
  }
 }

 if (zn == '\n')
   tp->tty_lfcount++;

 *(tp->tty_inhead) = zn;
 tp->tty_incount++;
 inc_inhead(tp);
 echo(tp, zn);
 return 1;
}