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zsig-t.vtc

/* -*- C -*-
 * zsigs-t.vtc: generate Red Line zephyr signatures
 * $Id$
 */


/* Array of stop names. */
redline_stops = alloc(22);
redline_stops[0] = "Alewife";
redline_stops[1] = "Davis Square";
redline_stops[2] = "Porter Square";
redline_stops[3] = "Harvard Square";
redline_stops[4] = "Central Square";
redline_stops[5] = "Kendall/MIT";
redline_stops[6] = "Charles/MGH";
redline_stops[7] = "Park Street";
redline_stops[8] = "Downtown Crossing";
redline_stops[9] = "South Station";
redline_stops[10] = "Broadway";
redline_stops[11] = "Andrew";
redline_stops[12] = "JFK/UMass";
redline_stops[13] = "Savin Hill";
redline_stops[14] = "Fields Corner";
redline_stops[15] = "Shawmut";
redline_stops[16] = "Ashmont";
redline_stops[17] = "North Quincy";
redline_stops[18] = "Wollaston";
redline_stops[19] = "Quincy Center";
redline_stops[20] = "Quincy Adams";
redline_stops[21] = "Braintree";

/* Array of destinations */
redline_dests = alloc(2);
redline_dests[0] = 16;
redline_dests[1] = 21;

/* Array of locations.  Each is an array of a stop number and a string. */
redline_num_locs = 0;
redline_locs = alloc(7);
func red_line_add_loc(stop, desc)
{
  redline_locs[redline_num_locs] = alloc(2);
  redline_locs[redline_num_locs][0] = stop;
  redline_locs[redline_num_locs][1] = desc;
  redline_num_locs++;
}

red_line_add_loc(1, "Tufts University");
red_line_add_loc(2, "Change here for the Commuter Rail");
red_line_add_loc(5, "MIT Cambridge Center");
red_line_add_loc(6, "Mass General Hospital");
red_line_add_loc(7, "Change here for the Green Line");
red_line_add_loc(8, "Change here for the Orange Line");
/* South Station is a special case in the code. */
red_line_add_loc(12, "Bayside Exposition Center");

/* Greg says the low bits of vt's rnd function aren't very random. */
func rl_rnd(n) [const]
{
  const = 17;
  return (rnd % (const * n)) / const;
}

Tredline ?:= new_assoc();

func new_redline() [rl]
{
  rl = alloc(6, Tredline);
  rl->stop = 0;
  rl->dest = 1;
  rl->dir = 1;
  rl->frame = 7;
  rl->msg = "";
  rl->win = cur_win;
  return rl;
}

REDLINE ?:= new_redline();
REDLINE_save ?:= new_redline();

/* State: current location... */
REDLINE->stop = 0;

/* ...current destination... */
REDLINE->dest = rl_rnd(2);

/* ...current direction... */
/* Direction 1 is away from Alewife, -1 is towards it. */
REDLINE->dir = 1;

/* ...current frame. */
/* Frames are:
 * 0: Next stop <station>
 * 1: Late Destination
 * 2: Entering <station>
 * 3: Location
 * 4: Announcements (1)
 * 5: Announcements (2)
 * 6: Announcements (3)
 * 7: Destination
 * 8: Late announcement */
REDLINE->frame = 7;

func red_line_frame_advance(rl)
{
  /* Start by just advancing the frame. */
  rl->frame++;
  
  /* If the frame is '9', reset the frame to '0' and advance the stop. */
  if (rl->frame > 8)
  {
    rl->frame = 0;
    red_line_stop_advance(rl);
  }
}

func red_line_stop_advance(rl) [i]
{
  /* Assumption: we're not at the end of the line. */
  rl->stop = rl->stop + rl->dir;

  /* Check to see if we are at the end of the line. */
  /* Check one: are we at Alewife? */
  if (rl->stop == 0)
  {
    /* Pick a destination at random. */
    rl->dest = rl_rnd(2);
    rl->dir = 1;
  }

  /* Check two: are we at our destination? */
  if (rl->stop == redline_dests[rl->dest])
  {
    /* Just turn around. */
    rl->dir = -1;
  }

  /* If we're on the Braintree branch and we think our next stop is
   * Savin Hill, jump to North Quincy.  If we think our next stop is
   * Ashmont, jump to JFK/UMass. */
  if (rl->dest == 1)
  {
    if (rl->stop == 13) rl->stop = 17;
    if (rl->stop == 16) rl->stop = 12;
  }
}

func red_line_find_loc(rl) [i]
{
  for (i = 0; i < redline_num_locs; i++)
  {
    if (redline_locs[i][0] == rl->stop)
      return redline_locs[i][1];
  }

  /* South Station is a special case. */
  if (rl->stop == 9)
  {
    if (rl_rnd(2) == 0)
    {
      return "Change here for the Commuter Rail";
    }
    else
    {
      return "Change here for Commuter Rail and Amtrak intercity service";
    }    
  }
  
  return 0;
}

func red_line_find_dest(rl)
{
  /* When is there a destination announcement? */
  /* There's never a destination announcement at all if we're heading
   * towards Alewife, unless we're at Braintree or Ashmont. */
  if (rl->dir == -1)
  {
    if ((rl->stop != 16) && (rl->stop != 21))
      return 0;
  }
  
  /* There's only a late destination announcement (after "next stop...")
   * between Andrew and one after JFK/UMass.  No announcement if headed
   * towards Alewife. */
  if (rl->frame == 1)
  {
    if ((rl->dir == -1) ||
        (rl->stop < 11) ||
        ((rl->stop > 13) && (rl->stop != 17)))
      return 0;
  }

  /* There's only a normal destination announcement (at the station, but
   * before a late announcement) up until JFK/UMass.  We've already
   * dealt with the case where we're headed towards Alewife. */
  if ((rl->frame == 7) && (rl->dir == 1))
  {
    if (rl->stop > 12)
      return 0;
  }
  
  return red_line_destination(rl);
}

func red_line_destination(rl) [dest]
{
  return "THE DESTINATION OF THIS TRAIN IS: " + red_line_dest_name(rl);
}

func red_line_dest_name(rl)
{
  if (rl->dir == -1)
    return redline_stops[0];
  else
    return redline_stops[redline_dests[rl->dest]];
}

func red_line_find_announce(rl)
{
  /* At a terminus? */
  if (rl->stop == 0 || rl->stop == redline_dests[rl->dest])
  {
    if (rl->frame == 4)
      return "Last stop.";
    if (rl->frame == 5)
      return "Thank you for riding the T.";
    if (rl->frame == 6)
      return "Don't forget your belongings.";
  }

  /* At Charles/MGH? */
  if (rl->stop == 6 && rl->frame == 4 && rl_rnd(4) == 0)
  {
    return "Mass Eye and Ear Infirmary";
  }
  
  return 0;
}

func red_line_find_late_announce(rl)
{
  /* At Harvard, Andrew, or Fields Corner? */
  if ((rl->stop == 3) || (rl->stop == 11) || (rl->stop == 14))
    return "No smoking please.";

  return 0;
}

func red_line_find_zsig(rl) [sig]
{
  /* Generate the signature as best as we can. */
  if (rl->frame == 0)
    sig = "Next stop, " + redline_stops[rl->stop];
  else if (rl->frame == 1)
    sig = red_line_find_dest(rl);
  else if (rl->frame == 2)
    sig = "Entering " + redline_stops[rl->stop];
  else if (rl->frame == 3)
    sig = red_line_find_loc(rl);
  else if (rl->frame >= 4 && rl->frame <= 6)
    sig = red_line_find_announce(rl);
  else if (rl->frame == 7)
    sig = red_line_find_dest(rl);
  else if (rl->frame == 8)
    sig = red_line_find_late_announce(rl);
  else
    sig = 0;
  
  return sig;
}

/* Uses the global REDLINE object. */
func red_line_zsig() [sig]
{
  /* Get a zsig.  Advance frames until we see a valid signature. */
  do
  {
    sig = red_line_find_zsig(REDLINE);
    red_line_frame_advance(REDLINE);
  } while (!sig);
  red_line_change_status(REDLINE);
  return sig;
}

func red_line_status_string(rl)
{
  return bprintf("[%s:%d->%s]", redline_stops[rl->stop], rl->frame,
                 red_line_dest_name(rl));
}

func red_line_change_status(rl) [str]
{
  str = red_line_status_string(rl);
  change_status(rl->win, rl->msg, str);
  rl->msg = str;
}

/* Print the status of the global REDLINE object. */
func red_line_status()
{
  printf("Stop: %s; frame %d. ", redline_stops[REDLINE->stop], REDLINE->frame);
  printf("Destination: %s; direction %d\n",
         redline_stops[redline_dests[REDLINE->dest]], REDLINE->dir);
}
add_cmd("rl_status", 0, .red_line_status, "/rl_status");

/* Save and restore the global REDLINE object. */
func red_line_save() { acopy(base(REDLINE_save), base(REDLINE), 6); }
add_cmd("rl_save", 0, .red_line_save, "/rl_save");
func red_line_restore() { acopy(base(REDLINE), base(REDLINE_save), 4);
                          red_line_change_status(REDLINE);}
add_cmd("rl_restore", 0, .red_line_restore, "/rl_restore");

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