roadstop.cpp

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/*
 * This file is part of OpenTTD.
 * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
 * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
 */
 
#include "stdafx.h"
#include "roadveh.h"
#include "core/pool_func.hpp"
#include "roadstop_base.h"
#include "station_base.h"
#include "vehicle_func.h"
 
#include "safeguards.h"
 
RoadStopPool _roadstop_pool("RoadStop");
INSTANTIATE_POOL_METHODS(RoadStop)
 
 
RoadStop::~RoadStop()
{
  /* When we are the head we need to free the entries */
  if (HasBit(this->status, RSSFB_BASE_ENTRY)) {
    delete this->east;
    delete this->west;
  }
 
  if (CleaningPool()) return;
}
 
RoadStop *RoadStop::GetNextRoadStop(const RoadVehicle *v) const
{
  for (RoadStop *rs = this->next; rs != nullptr; rs = rs->next) {
    /* The vehicle cannot go to this roadstop (different roadtype) */
    if (!HasTileAnyRoadType(rs->xy, v->compatible_roadtypes)) continue;
    /* The vehicle is articulated and can therefore not go to a standard road stop. */
    if (IsBayRoadStopTile(rs->xy) && v->HasArticulatedPart()) continue;
 
    /* The vehicle can actually go to this road stop. So, return it! */
    return rs;
  }
 
  return nullptr;
}
 
void RoadStop::MakeDriveThrough()
{
  assert(this->east == nullptr && this->west == nullptr);
 
  RoadStopType rst = GetRoadStopType(this->xy);
  Axis axis = GetDriveThroughStopAxis(this->xy);
  TileIndexDiff offset = TileOffsByAxis(axis);
 
  /* Information about the tile north of us */
  TileIndex north_tile = this->xy - offset;
  bool north = IsDriveThroughRoadStopContinuation(this->xy, north_tile);
  RoadStop *rs_north = north ? RoadStop::GetByTile(north_tile, rst) : nullptr;
 
  /* Information about the tile south of us */
  TileIndex south_tile = this->xy + offset;
  bool south = IsDriveThroughRoadStopContinuation(this->xy, south_tile);
  RoadStop *rs_south = south ? RoadStop::GetByTile(south_tile, rst) : nullptr;
 
  /* Amount of road stops that will be added to the 'northern' head */
  int added = 1;
  if (north && rs_north->east != nullptr) { // (east != nullptr) == (west != nullptr)
    /* There is a more northern one, so this can join them */
    this->east = rs_north->east;
    this->west = rs_north->west;
 
    if (south && rs_south->east != nullptr) { // (east != nullptr) == (west != nullptr)
      /* There more southern tiles too, they must 'join' us too */
      ClrBit(rs_south->status, RSSFB_BASE_ENTRY);
      this->east->occupied += rs_south->east->occupied;
      this->west->occupied += rs_south->west->occupied;
 
      /* Free the now unneeded entry structs */
      delete rs_south->east;
      delete rs_south->west;
 
      /* Make all 'children' of the southern tile take the new master */
      for (; IsDriveThroughRoadStopContinuation(this->xy, south_tile); south_tile += offset) {
        rs_south = RoadStop::GetByTile(south_tile, rst);
        if (rs_south->east == nullptr) break;
        rs_south->east = rs_north->east;
        rs_south->west = rs_north->west;
        added++;
      }
    }
  } else if (south && rs_south->east != nullptr) { // (east != nullptr) == (west != nullptr)
    /* There is one to the south, but not to the north... so we become 'parent' */
    this->east = rs_south->east;
    this->west = rs_south->west;
    SetBit(this->status, RSSFB_BASE_ENTRY);
    ClrBit(rs_south->status, RSSFB_BASE_ENTRY);
  } else {
    /* We are the only... so we are automatically the master */
    this->east = new Entry();
    this->west = new Entry();
    SetBit(this->status, RSSFB_BASE_ENTRY);
  }
 
  /* Now update the lengths */
  added *= TILE_SIZE;
  this->east->length += added;
  this->west->length += added;
}
 
void RoadStop::ClearDriveThrough()
{
  assert(this->east != nullptr && this->west != nullptr);
 
  RoadStopType rst = GetRoadStopType(this->xy);
  Axis axis = GetDriveThroughStopAxis(this->xy);
  TileIndexDiff offset = TileOffsByAxis(axis);
 
  /* Information about the tile north of us */
  TileIndex north_tile = this->xy - offset;
  bool north = IsDriveThroughRoadStopContinuation(this->xy, north_tile);
  RoadStop *rs_north = north ? RoadStop::GetByTile(north_tile, rst) : nullptr;
 
  /* Information about the tile south of us */
  TileIndex south_tile = this->xy + offset;
  bool south = IsDriveThroughRoadStopContinuation(this->xy, south_tile);
  RoadStop *rs_south = south ? RoadStop::GetByTile(south_tile, rst) : nullptr;
 
  /* Must only be cleared after we determined which neighbours are
   * part of our little entry 'queue' */
  DoClearSquare(this->xy);
 
  if (north) {
    /* There is a tile to the north, so we can't clear ourselves. */
    if (south) {
      /* There are more southern tiles too, they must be split;
       * first make the new southern 'base' */
      SetBit(rs_south->status, RSSFB_BASE_ENTRY);
      rs_south->east = new Entry();
      rs_south->west = new Entry();
 
      /* Keep track of the base because we need it later on */
      RoadStop *rs_south_base = rs_south;
      TileIndex base_tile = south_tile;
 
      /* Make all (even more) southern stops part of the new entry queue */
      for (south_tile += offset; IsDriveThroughRoadStopContinuation(base_tile, south_tile); south_tile += offset) {
        rs_south = RoadStop::GetByTile(south_tile, rst);
        rs_south->east = rs_south_base->east;
        rs_south->west = rs_south_base->west;
      }
 
      /* Find the other end; the northern most tile */
      for (; IsDriveThroughRoadStopContinuation(base_tile, north_tile); north_tile -= offset) {
        rs_north = RoadStop::GetByTile(north_tile, rst);
      }
 
      /* We have to rebuild the entries because we cannot easily determine
       * how full each part is. So instead of keeping and maintaining a list
       * of vehicles and using that to 'rebuild' the occupied state we just
       * rebuild it from scratch as that removes lots of maintenance code
       * for the vehicle list and it's faster in real games as long as you
       * do not keep split and merge road stop every tick by the millions. */
      rs_south_base->east->Rebuild(rs_south_base);
      rs_south_base->west->Rebuild(rs_south_base);
 
      assert(HasBit(rs_north->status, RSSFB_BASE_ENTRY));
      rs_north->east->Rebuild(rs_north);
      rs_north->west->Rebuild(rs_north);
    } else {
      /* Only we left, so simple update the length. */
      rs_north->east->length -= TILE_SIZE;
      rs_north->west->length -= TILE_SIZE;
    }
  } else if (south) {
    /* There is only something to the south. Hand over the base entry */
    SetBit(rs_south->status, RSSFB_BASE_ENTRY);
    rs_south->east->length -= TILE_SIZE;
    rs_south->west->length -= TILE_SIZE;
  } else {
    /* We were the last */
    delete this->east;
    delete this->west;
  }
 
  /* Make sure we don't get used for something 'incorrect' */
  ClrBit(this->status, RSSFB_BASE_ENTRY);
  this->east = nullptr;
  this->west = nullptr;
}
 
void RoadStop::Leave(RoadVehicle *rv)
{
  if (IsBayRoadStopTile(rv->tile)) {
    /* Vehicle is leaving a road stop tile, mark bay as free */
    this->FreeBay(HasBit(rv->state, RVS_USING_SECOND_BAY));
    this->SetEntranceBusy(false);
  } else {
    /* Otherwise just leave the drive through's entry cache. */
    this->GetEntry(DirToDiagDir(rv->direction))->Leave(rv);
  }
}
 
bool RoadStop::Enter(RoadVehicle *rv)
{
  if (IsBayRoadStopTile(this->xy)) {
    /* For normal (non drive-through) road stops
     * Check if station is busy or if there are no free bays or whether it is a articulated vehicle. */
    if (this->IsEntranceBusy() || !this->HasFreeBay() || rv->HasArticulatedPart()) return false;
 
    SetBit(rv->state, RVS_IN_ROAD_STOP);
 
    /* Allocate a bay and update the road state */
    uint bay_nr = this->AllocateBay();
    SB(rv->state, RVS_USING_SECOND_BAY, 1, bay_nr);
 
    /* Mark the station entrance as busy */
    this->SetEntranceBusy(true);
    return true;
  }
 
  /* Vehicles entering a drive-through stop from the 'normal' side use first bay (bay 0). */
  this->GetEntry(DirToDiagDir(rv->direction))->Enter(rv);
 
  /* Indicate a drive-through stop */
  SetBit(rv->state, RVS_IN_DT_ROAD_STOP);
  return true;
}
 
/* static */ RoadStop *RoadStop::GetByTile(TileIndex tile, RoadStopType type)
{
  const Station *st = Station::GetByTile(tile);
 
  for (RoadStop *rs = st->GetPrimaryRoadStop(type);; rs = rs->next) {
    if (rs->xy == tile) return rs;
    assert(rs->next != nullptr);
  }
}
 
void RoadStop::Entry::Leave(const RoadVehicle *rv)
{
  this->occupied -= rv->gcache.cached_total_length;
  assert(this->occupied >= 0);
}
 
void RoadStop::Entry::Enter(const RoadVehicle *rv)
{
  /* we cannot assert on this->occupied < this->length because of the
   * remote possibility that RVs are running through each other when
   * trying to prevention an infinite jam. */
  this->occupied += rv->gcache.cached_total_length;
}
 
/* static */ bool RoadStop::IsDriveThroughRoadStopContinuation(TileIndex rs, TileIndex next)
{
  return IsTileType(next, MP_STATION) &&
      GetStationIndex(next) == GetStationIndex(rs) &&
      GetStationType(next) == GetStationType(rs) &&
      IsDriveThroughStopTile(next) &&
      GetDriveThroughStopAxis(next) == GetDriveThroughStopAxis(rs);
}
 
typedef std::list<const RoadVehicle *> RVList; 
 
struct RoadStopEntryRebuilderHelper {
  RVList vehicles;   
  DiagDirection dir; 
};
 
Vehicle *FindVehiclesInRoadStop(Vehicle *v, void *data)
{
  RoadStopEntryRebuilderHelper *rserh = (RoadStopEntryRebuilderHelper*)data;
  /* Not a RV or not in the right direction or crashed :( */
  if (v->type != VEH_ROAD || DirToDiagDir(v->direction) != rserh->dir || !v->IsPrimaryVehicle() || (v->vehstatus & VS_CRASHED) != 0) return nullptr;
 
  RoadVehicle *rv = RoadVehicle::From(v);
  /* Don't add ones not in a road stop */
  if (rv->state < RVSB_IN_ROAD_STOP) return nullptr;
 
  /* Do not add duplicates! */
  for (const auto &it : rserh->vehicles) {
    if (rv == it) return nullptr;
  }
 
  rserh->vehicles.push_back(rv);
  return nullptr;
}
 
static DiagDirection GetEntryDirection(bool east, Axis axis)
{
  switch (axis) {
    case AXIS_X: return east ? DIAGDIR_NE : DIAGDIR_SW;
    case AXIS_Y: return east ? DIAGDIR_SE : DIAGDIR_NW;
    default: NOT_REACHED();
  }
}
 
void RoadStop::Entry::Rebuild(const RoadStop *rs, int side)
{
  assert(HasBit(rs->status, RSSFB_BASE_ENTRY));
 
  Axis axis = GetDriveThroughStopAxis(rs->xy);
  if (side == -1) side = (rs->east == this);
 
  RoadStopEntryRebuilderHelper rserh;
  rserh.dir = GetEntryDirection(side, axis);
 
  this->length = 0;
  TileIndexDiff offset = TileOffsByAxis(axis);
  for (TileIndex tile = rs->xy; IsDriveThroughRoadStopContinuation(rs->xy, tile); tile += offset) {
    this->length += TILE_SIZE;
    FindVehicleOnPos(tile, &rserh, FindVehiclesInRoadStop);
  }
 
  this->occupied = 0;
  for (const auto &it : rserh.vehicles) {
    this->occupied += it->gcache.cached_total_length;
  }
}
 
 
void RoadStop::Entry::CheckIntegrity(const RoadStop *rs) const
{
  if (!HasBit(rs->status, RSSFB_BASE_ENTRY)) return;
 
  /* The tile 'before' the road stop must not be part of this 'line' */
  assert(IsDriveThroughStopTile(rs->xy));
  assert(!IsDriveThroughRoadStopContinuation(rs->xy, rs->xy - TileOffsByAxis(GetDriveThroughStopAxis(rs->xy))));
 
  Entry temp;
  temp.Rebuild(rs, rs->east == this);
  if (temp.length != this->length || temp.occupied != this->occupied) NOT_REACHED();
}