refresh.cpp

/*
 * 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 "../core/bitmath_func.hpp"
#include "../station_func.h"
#include "../engine_base.h"
#include "../vehicle_func.h"
#include "refresh.h"
#include "linkgraph.h"
 
#include "../safeguards.h"
 
/* static */ void LinkRefresher::Run(Vehicle *v, bool allow_merge, bool is_full_loading)
{
  /* If there are no orders we can't predict anything.*/
  if (v->orders == nullptr) return;
 
  /* Make sure the first order is a useful order. */
  const Order *first = v->orders->GetNextDecisionNode(v->GetOrder(v->cur_implicit_order_index), 0);
  if (first == nullptr) return;
 
  HopSet seen_hops;
  LinkRefresher refresher(v, &seen_hops, allow_merge, is_full_loading);
 
  refresher.RefreshLinks(first, first, v->last_loading_station != StationID::Invalid() ? RefreshFlags{RefreshFlag::HasCargo} : RefreshFlags{});
}
 
LinkRefresher::LinkRefresher(Vehicle *vehicle, HopSet *seen_hops, bool allow_merge, bool is_full_loading) :
  vehicle(vehicle), seen_hops(seen_hops), cargo(INVALID_CARGO), allow_merge(allow_merge),
  is_full_loading(is_full_loading)
{
  /* Assemble list of capacities and set last loading stations to 0. */
  for (Vehicle *v = this->vehicle; v != nullptr; v = v->Next()) {
    this->refit_capacities.push_back(RefitDesc(v->cargo_type, v->cargo_cap, v->refit_cap));
    if (v->refit_cap > 0) {
      assert(v->cargo_type < NUM_CARGO);
      this->capacities[v->cargo_type] += v->refit_cap;
    }
  }
}
 
bool LinkRefresher::HandleRefit(CargoType refit_cargo)
{
  this->cargo = refit_cargo;
  RefitList::iterator refit_it = this->refit_capacities.begin();
  bool any_refit = false;
  for (Vehicle *v = this->vehicle; v != nullptr; v = v->Next()) {
    const Engine *e = Engine::Get(v->engine_type);
    if (!HasBit(e->info.refit_mask, this->cargo)) {
      ++refit_it;
      continue;
    }
    any_refit = true;
 
    /* Back up the vehicle's cargo type */
    CargoType temp_cargo_type = v->cargo_type;
    uint8_t temp_subtype = v->cargo_subtype;
    v->cargo_type = this->cargo;
    v->cargo_subtype = GetBestFittingSubType(v, v, this->cargo);
 
    uint16_t mail_capacity = 0;
    uint amount = e->DetermineCapacity(v, &mail_capacity);
 
    /* Restore the original cargo type */
    v->cargo_type = temp_cargo_type;
    v->cargo_subtype = temp_subtype;
 
    /* Skip on next refit. */
    if (this->cargo != refit_it->cargo && refit_it->remaining > 0) {
      this->capacities[refit_it->cargo] -= refit_it->remaining;
      refit_it->remaining = 0;
    } else if (amount < refit_it->remaining) {
      this->capacities[refit_it->cargo] -= refit_it->remaining - amount;
      refit_it->remaining = amount;
    }
    refit_it->capacity = amount;
    refit_it->cargo = this->cargo;
 
    ++refit_it;
 
    /* Special case for aircraft with mail. */
    if (v->type == VEH_AIRCRAFT) {
      if (mail_capacity < refit_it->remaining) {
        this->capacities[refit_it->cargo] -= refit_it->remaining - mail_capacity;
        refit_it->remaining = mail_capacity;
      }
      refit_it->capacity = mail_capacity;
      break; // aircraft have only one vehicle
    }
  }
  return any_refit;
}
 
void LinkRefresher::ResetRefit()
{
  for (auto &it : this->refit_capacities) {
    if (it.remaining == it.capacity) continue;
    this->capacities[it.cargo] += it.capacity - it.remaining;
    it.remaining = it.capacity;
  }
}
 
const Order *LinkRefresher::PredictNextOrder(const Order *cur, const Order *next, RefreshFlags flags, uint num_hops)
{
  /* next is good if it's either nullptr (then the caller will stop the
   * evaluation) or if it's not conditional and the caller allows it to be
   * chosen (by setting RefreshFlag::UseNext). */
  while (next != nullptr && (!flags.Test(RefreshFlag::UseNext) || next->IsType(OT_CONDITIONAL))) {
 
    /* After the first step any further non-conditional order is good,
     * regardless of previous RefreshFlag::UseNext settings. The case of cur and next or
     * their respective stations being equal is handled elsewhere. */
    flags.Set(RefreshFlag::UseNext);
 
    if (next->IsType(OT_CONDITIONAL)) {
      const Order *skip_to = this->vehicle->orders->GetNextDecisionNode(
          this->vehicle->orders->GetOrderAt(next->GetConditionSkipToOrder()), num_hops);
      if (skip_to != nullptr && num_hops < this->vehicle->orders->GetNumOrders()) {
        /* Make copies of capacity tracking lists. There is potential
         * for optimization here: If the vehicle never refits we don't
         * need to copy anything. Also, if we've seen the branched link
         * before we don't need to branch at all. */
        LinkRefresher branch(*this);
        branch.RefreshLinks(cur, skip_to, flags, num_hops + 1);
      }
    }
 
    /* Reassign next with the following stop. This can be a station or a
     * depot.*/
    next = this->vehicle->orders->GetNextDecisionNode(
        this->vehicle->orders->GetNext(next), num_hops++);
  }
  return next;
}
 
void LinkRefresher::RefreshStats(const Order *cur, const Order *next)
{
  StationID next_station = next->GetDestination().ToStationID();
  Station *st = Station::GetIfValid(cur->GetDestination().ToStationID());
  if (st != nullptr && next_station != StationID::Invalid() && next_station != st->index) {
    Station *st_to = Station::Get(next_station);
    for (CargoType cargo = 0; cargo < NUM_CARGO; ++cargo) {
      /* Refresh the link and give it a minimum capacity. */
 
      uint cargo_quantity = this->capacities[cargo];
      if (cargo_quantity == 0) continue;
 
      if (this->vehicle->GetDisplayMaxSpeed() == 0) continue;
 
      /* If not allowed to merge link graphs, make sure the stations are
       * already in the same link graph. */
      if (!this->allow_merge && st->goods[cargo].link_graph != st_to->goods[cargo].link_graph) {
        continue;
      }
 
      /* A link is at least partly restricted if a vehicle can't load at its source. */
      EdgeUpdateMode restricted_mode = (cur->GetLoadType() & OLFB_NO_LOAD) == 0 ?
            EdgeUpdateMode::Unrestricted : EdgeUpdateMode::Restricted;
      /* This estimates the travel time of the link as the time needed
       * to travel between the stations at half the max speed of the consist.
       * The result is in tiles/tick (= 2048 km-ish/h). */
      uint32_t time_estimate = DistanceManhattan(st->xy, st_to->xy) * 4096U / this->vehicle->GetDisplayMaxSpeed();
 
      /* If the vehicle is currently full loading, increase the capacities at the station
       * where it is loading by an estimate of what it would have transported if it wasn't
       * loading. Don't do that if the vehicle has been waiting for longer than the entire
       * order list is supposed to take, though. If that is the case the total duration is
       * probably far off and we'd greatly overestimate the capacity by increasing.*/
      if (this->is_full_loading && this->vehicle->orders != nullptr &&
          st->index == vehicle->last_station_visited &&
          this->vehicle->orders->GetTotalDuration() > this->vehicle->current_order_time) {
        uint effective_capacity = cargo_quantity * this->vehicle->load_unload_ticks;
        if (effective_capacity > (uint)this->vehicle->orders->GetTotalDuration()) {
          IncreaseStats(st, cargo, next_station, effective_capacity /
              this->vehicle->orders->GetTotalDuration(), 0, 0,
              {EdgeUpdateMode::Increase, restricted_mode});
        } else if (RandomRange(this->vehicle->orders->GetTotalDuration()) < effective_capacity) {
          IncreaseStats(st, cargo, next_station, 1, 0, 0, {EdgeUpdateMode::Increase, restricted_mode});
        } else {
          IncreaseStats(st, cargo, next_station, cargo_quantity, 0, time_estimate, {EdgeUpdateMode::Refresh, restricted_mode});
        }
      } else {
        IncreaseStats(st, cargo, next_station, cargo_quantity, 0, time_estimate, {EdgeUpdateMode::Refresh, restricted_mode});
      }
    }
  }
}
 
void LinkRefresher::RefreshLinks(const Order *cur, const Order *next, RefreshFlags flags, uint num_hops)
{
  while (next != nullptr) {
 
    if ((next->IsType(OT_GOTO_DEPOT) || next->IsType(OT_GOTO_STATION)) && next->IsRefit()) {
      flags.Set(RefreshFlag::WasRefit);
      if (!next->IsAutoRefit()) {
        this->HandleRefit(next->GetRefitCargo());
      } else if (!flags.Test(RefreshFlag::InAutorefit)) {
        flags.Set(RefreshFlag::InAutorefit);
        LinkRefresher backup(*this);
        for (CargoType cargo = 0; cargo != NUM_CARGO; ++cargo) {
          if (CargoSpec::Get(cargo)->IsValid() && this->HandleRefit(cargo)) {
            this->RefreshLinks(cur, next, flags, num_hops);
            *this = backup;
          }
        }
      }
    }
 
    /* Only reset the refit capacities if the "previous" next is a station,
     * meaning that either the vehicle was refit at the previous station or
     * it wasn't at all refit during the current hop. */
    if (flags.Test(RefreshFlag::WasRefit) && (next->IsType(OT_GOTO_STATION) || next->IsType(OT_IMPLICIT))) {
      flags.Set(RefreshFlag::ResetRefit);
    } else {
      flags.Reset(RefreshFlag::ResetRefit);
    }
 
    next = this->PredictNextOrder(cur, next, flags, num_hops);
    if (next == nullptr) break;
    Hop hop(cur->index, next->index, this->cargo);
    if (this->seen_hops->find(hop) != this->seen_hops->end()) {
      break;
    } else {
      this->seen_hops->insert(hop);
    }
 
    /* Don't use the same order again, but choose a new one in the next round. */
    flags.Reset(RefreshFlag::UseNext);
 
    /* Skip resetting and link refreshing if next order won't do anything with cargo. */
    if (!next->IsType(OT_GOTO_STATION) && !next->IsType(OT_IMPLICIT)) continue;
 
    if (flags.Test(RefreshFlag::ResetRefit)) {
      this->ResetRefit();
      flags.Reset({RefreshFlag::ResetRefit, RefreshFlag::WasRefit});
    }
 
    if (cur->IsType(OT_GOTO_STATION) || cur->IsType(OT_IMPLICIT)) {
      if (cur->CanLeaveWithCargo(flags.Test(RefreshFlag::HasCargo))) {
        flags.Set(RefreshFlag::HasCargo);
        this->RefreshStats(cur, next);
      } else {
        flags.Reset(RefreshFlag::HasCargo);
      }
    }
 
    /* "cur" is only assigned here if the stop is a station so that
     * whenever stats are to be increased two stations can be found. */
    cur = next;
  }
}