town_sl.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 <https://www.gnu.org/licenses/old-licenses/gpl-2.0>.
 */

 
#include "../stdafx.h"
 
#include "saveload.h"
#include "compat/town_sl_compat.h"
 
#include "newgrf_sl.h"
#include "../newgrf_house.h"
#include "../town.h"
#include "../landscape.h"
#include "../subsidy_func.h"
#include "../strings_func.h"
#include "../misc/history_func.hpp"
 
#include "../safeguards.h"

void RebuildTownCaches()
{
  InitializeBuildingCounts();
  RebuildTownKdtree();
 
  /* Reset town population and num_houses */
  for (Town *town : Town::Iterate()) {
    town->cache.population = 0;
    town->cache.num_houses = 0;
  }
 
  for (const auto t : Map::Iterate()) {
    if (!IsTileType(t, TileType::House)) continue;
 
    HouseID house_id = GetHouseType(t);
    Town *town = Town::GetByTile(t);
    IncreaseBuildingCount(town, house_id);
    if (IsHouseCompleted(t)) town->cache.population += HouseSpec::Get(house_id)->population;
 
    /* Increase the number of houses for every house, but only once. */
    if (GetHouseNorthPart(house_id) == TileDiffXY(0, 0)) town->cache.num_houses++;
  }
 
  /* Update the population and num_house dependent values */
  for (Town *town : Town::Iterate()) {
    UpdateTownRadius(town);
  }
}

void UpdateHousesAndTowns()
{
  for (const auto t : Map::Iterate()) {
    if (!IsTileType(t, TileType::House)) continue;
 
    HouseID house_id = GetCleanHouseType(t);
    if (!HouseSpec::Get(house_id)->enabled && house_id >= NEW_HOUSE_OFFSET) {
      /* The specs for this type of house are not available any more, so
       * replace it with the substitute original house type. */
      house_id = _house_mngr.GetSubstituteID(house_id);
      SetHouseType(t, house_id);
    }
  }
 
  /* Check for cases when a NewGRF has set a wrong house substitute type. */
  for (const TileIndex &t : Map::Iterate()) {
    if (!IsTileType(t, TileType::House)) continue;
 
    HouseID house_type = GetCleanHouseType(t);
    TileIndex north_tile = t + GetHouseNorthPart(house_type); // modifies 'house_type'!
    if (t == north_tile) {
      const HouseSpec *hs = HouseSpec::Get(house_type);
      bool valid_house = true;
      if (hs->building_flags.Test(BuildingFlag::Size2x1)) {
        TileIndex tile = t + TileDiffXY(1, 0);
        if (!IsTileType(tile, TileType::House) || GetCleanHouseType(tile) != house_type + 1) valid_house = false;
      } else if (hs->building_flags.Test(BuildingFlag::Size1x2)) {
        TileIndex tile = t + TileDiffXY(0, 1);
        if (!IsTileType(tile, TileType::House) || GetCleanHouseType(tile) != house_type + 1) valid_house = false;
      } else if (hs->building_flags.Test(BuildingFlag::Size2x2)) {
        TileIndex tile = t + TileDiffXY(0, 1);
        if (!IsTileType(tile, TileType::House) || GetCleanHouseType(tile) != house_type + 1) valid_house = false;
        tile = t + TileDiffXY(1, 0);
        if (!IsTileType(tile, TileType::House) || GetCleanHouseType(tile) != house_type + 2) valid_house = false;
        tile = t + TileDiffXY(1, 1);
        if (!IsTileType(tile, TileType::House) || GetCleanHouseType(tile) != house_type + 3) valid_house = false;
      }
      /* If not all tiles of this house are present remove the house.
       * The other tiles will get removed later in this loop because
       * their north tile is not the correct type anymore. */
      if (!valid_house) DoClearSquare(t);
    } else if (!IsTileType(north_tile, TileType::House) || GetCleanHouseType(north_tile) != house_type) {
      /* This tile should be part of a multi-tile building but the
       * north tile of this house isn't on the map. */
      DoClearSquare(t);
    }
  }
 
  RebuildTownCaches();
}
 
 
class SlTownOldSupplied : public DefaultSaveLoadHandler<SlTownOldSupplied, Town> {
public:
  static inline const SaveLoad description[] = {
    SLE_CONDVAR(TransportedCargoStat<uint32_t>, old_max, VarTypes::U32, SaveLoadVersion::ScriptTownGrowth, SaveLoadVersion::MaxVersion),
    SLE_CONDVAR(TransportedCargoStat<uint32_t>, new_max, VarTypes::U32, SaveLoadVersion::ScriptTownGrowth, SaveLoadVersion::MaxVersion),
    SLE_CONDVAR(TransportedCargoStat<uint32_t>, old_act, VarTypes::U32, SaveLoadVersion::ScriptTownGrowth, SaveLoadVersion::MaxVersion),
    SLE_CONDVAR(TransportedCargoStat<uint32_t>, new_act, VarTypes::U32, SaveLoadVersion::ScriptTownGrowth, SaveLoadVersion::MaxVersion),
  };
  static inline const SaveLoadCompatTable compat_description = _town_supplied_sl_compat;

  size_t GetNumCargo() const
  {
    if (IsSavegameVersionBefore(SaveLoadVersion::ExtendCargotypes)) return 32;
    if (IsSavegameVersionBefore(SaveLoadVersion::SaveloadListLength)) return NUM_CARGO;
    /* Read from the savegame how long the list is. */
    return SlGetStructListLength(NUM_CARGO);
  }
 
  void Load(Town *t) const override
  {
    size_t num_cargo = this->GetNumCargo();
    for (size_t i = 0; i < num_cargo; i++) {
      TransportedCargoStat<uint32_t> cargo_stat;
      SlObject(&cargo_stat, this->GetLoadDescription());
 
      /* Ignore empty statistics. */
      if (cargo_stat.new_act == 0 && cargo_stat.new_max == 0 && cargo_stat.old_act == 0 && cargo_stat.old_max == 0) continue;
 
      auto &s = t->supplied.emplace_back(static_cast<CargoType>(i));
      s.history[LAST_MONTH].production = cargo_stat.old_max;
      s.history[LAST_MONTH].transported = cargo_stat.old_act;
      s.history[THIS_MONTH].production = cargo_stat.new_max;
      s.history[THIS_MONTH].transported = cargo_stat.new_act;
    }
  }
};
 
class SlTownSuppliedHistory : public DefaultSaveLoadHandler<SlTownSuppliedHistory, Town::SuppliedCargo> {
public:
  static inline const SaveLoad description[] = {
     SLE_VAR(Town::SuppliedHistory, production, VarTypes::U32),
     SLE_VAR(Town::SuppliedHistory, transported, VarTypes::U32),
  };
  static inline const SaveLoadCompatTable compat_description = {};
 
  void Save(Town::SuppliedCargo *p) const override
  {
    SlSetStructListLength(p->history.size());
 
    for (auto &h : p->history) {
      SlObject(&h, this->GetDescription());
    }
  }
 
  void Load(Town::SuppliedCargo *p) const override
  {
    size_t len = SlGetStructListLength(p->history.size());
 
    for (auto &h : p->history) {
      if (--len > p->history.size()) break; // unsigned so wraps after hitting zero.
      SlObject(&h, this->GetLoadDescription());
    }
  }
};
 
class SlTownSupplied : public VectorSaveLoadHandler<SlTownSupplied, Town, Town::SuppliedCargo> {
public:
  inline static const SaveLoad description[] = {
    SLE_VAR(Town::SuppliedCargo, cargo, VarTypes::U8),
    SLEG_STRUCTLIST("history", SlTownSuppliedHistory),
  };
  inline const static SaveLoadCompatTable compat_description = {};
 
  std::vector<Town::SuppliedCargo> &GetVector(Town *t) const override { return t->supplied; }
};

class SlTownAcceptedHistory : public DefaultSaveLoadHandler<SlTownAcceptedHistory, Town::AcceptedCargo> {
public:
  static inline const SaveLoad description[] = {
     SLE_VAR(Town::AcceptedHistory, accepted, VarTypes::U32),
  };

  static inline const SaveLoadCompatTable compat_description = {};
 
  void Save(Town::AcceptedCargo *p) const override
  {
    SlSetStructListLength(p->history.size());
 
    for (auto &h : p->history) {
      SlObject(&h, this->GetDescription());
    }
  }
 
  void Load(Town::AcceptedCargo *p) const override
  {
    size_t len = SlGetStructListLength(p->history.size());
 
    for (auto &h : p->history) {
      if (--len > p->history.size()) break; // unsigned so wraps after hitting zero.
      SlObject(&h, this->GetLoadDescription());
    }
  }
};

class SlTownAccepted : public VectorSaveLoadHandler<SlTownAccepted, Town, Town::AcceptedCargo> {
public:
  inline static const SaveLoad description[] = {
    SLE_VAR(Town::AcceptedCargo, cargo, VarTypes::U8),
    SLEG_STRUCTLIST("history", SlTownAcceptedHistory),
  };

  inline const static SaveLoadCompatTable compat_description = {};
 
  std::vector<Town::AcceptedCargo> &GetVector(Town *t) const override { return t->accepted; }
};
 
class SlTownReceived : public DefaultSaveLoadHandler<SlTownReceived, Town> {
public:
  static inline const SaveLoad description[] = {
    SLE_CONDVAR(TransportedCargoStat<uint16_t>, old_max, VarTypes::U16, SaveLoadVersion::ScriptTownGrowth, SaveLoadVersion::MaxVersion),
    SLE_CONDVAR(TransportedCargoStat<uint16_t>, new_max, VarTypes::U16, SaveLoadVersion::ScriptTownGrowth, SaveLoadVersion::MaxVersion),
    SLE_CONDVAR(TransportedCargoStat<uint16_t>, old_act, VarTypes::U16, SaveLoadVersion::ScriptTownGrowth, SaveLoadVersion::MaxVersion),
    SLE_CONDVAR(TransportedCargoStat<uint16_t>, new_act, VarTypes::U16, SaveLoadVersion::ScriptTownGrowth, SaveLoadVersion::MaxVersion),
  };
  static inline const SaveLoadCompatTable compat_description = _town_received_sl_compat;
 
  void Save(Town *t) const override
  {
    SlSetStructListLength(std::size(t->received));
    for (auto &received : t->received) {
      SlObject(&received, this->GetDescription());
    }
  }
 
  void Load(Town *t) const override
  {
    size_t length = IsSavegameVersionBefore(SaveLoadVersion::SaveloadListLength) ? to_underlying(TownAcceptanceEffect::End) : SlGetStructListLength(to_underlying(TownAcceptanceEffect::End));
    for (size_t i = 0; i < length; i++) {
      SlObject(&t->received[static_cast<TownAcceptanceEffect>(i)], this->GetLoadDescription());
    }
  }
};
 
class SlTownAcceptanceMatrix : public DefaultSaveLoadHandler<SlTownAcceptanceMatrix, Town> {
private:
  struct AcceptanceMatrix {
    TileArea area;
    static const uint GRID = 4;
  };
public:
  static inline const SaveLoad description[] = {
    SLE_VAR(AcceptanceMatrix, area.tile, VarTypes::U32),
    SLE_VAR(AcceptanceMatrix, area.w,    VarTypes::U16),
    SLE_VAR(AcceptanceMatrix, area.h,    VarTypes::U16),
  };
  static inline const SaveLoadCompatTable compat_description = _town_acceptance_matrix_sl_compat;
 
  void Load(Town *) const override
  {
    /* Discard now unused acceptance matrix. */
    AcceptanceMatrix dummy;
    SlObject(&dummy, this->GetLoadDescription());
    if (dummy.area.w != 0) {
      uint arr_len = dummy.area.w / AcceptanceMatrix::GRID * dummy.area.h / AcceptanceMatrix::GRID;
      SlSkipBytes(4 * arr_len);
    }
  }
};
 
static std::array<Town::SuppliedHistory, 2> _old_pass_supplied{};
static std::array<Town::SuppliedHistory, 2> _old_mail_supplied{};
 
static const SaveLoad _town_desc[] = {
  SLE_CONDVAR(Town, xy, VarFileType::U16 | VarMemType::U32, SaveLoadVersion::MinVersion, SaveLoadVersion::MultipleRoadStops),
  SLE_CONDVAR(Town, xy, VarTypes::U32, SaveLoadVersion::MultipleRoadStops, SaveLoadVersion::MaxVersion),
 
  SLE_CONDVAR(Town, townnamegrfid, VarTypes::U32, SaveLoadVersion::NewGRFTownNames, SaveLoadVersion::MaxVersion),
      SLE_VAR(Town, townnametype,          VarTypes::U16),
      SLE_VAR(Town, townnameparts,         VarTypes::U32),
  SLE_CONDSSTR(Town, name, VarTypes::STR | StringValidationSetting::AllowControlCode, SaveLoadVersion::ReplaceCustomNameArray, SaveLoadVersion::MaxVersion),
 
      SLE_VAR(Town, flags,                 VarTypes::U8),
  SLE_CONDVAR(Town, statues, VarFileType::U8 | VarMemType::U16, SaveLoadVersion::MinVersion, SaveLoadVersion::MoreCompanies),
  SLE_CONDVAR(Town, statues, VarTypes::U16, SaveLoadVersion::MoreCompanies, SaveLoadVersion::MaxVersion),
 
  SLE_CONDVAR(Town, have_ratings, VarFileType::U8 | VarMemType::U16, SaveLoadVersion::MinVersion, SaveLoadVersion::MoreCompanies),
  SLE_CONDVAR(Town, have_ratings, VarTypes::U16, SaveLoadVersion::MoreCompanies, SaveLoadVersion::MaxVersion),
  SLE_CONDARR(Town, ratings, VarTypes::I16, 8, SaveLoadVersion::MinVersion, SaveLoadVersion::MoreCompanies),
  SLE_CONDARR(Town, ratings, VarTypes::I16, MAX_COMPANIES, SaveLoadVersion::MoreCompanies, SaveLoadVersion::MaxVersion),
  SLE_CONDARR(Town, unwanted, VarTypes::I8, 8, SaveLoadVersion::TownTolerancePauseMode, SaveLoadVersion::MoreCompanies),
  SLE_CONDARR(Town, unwanted, VarTypes::I8, MAX_COMPANIES, SaveLoadVersion::MoreCompanies, SaveLoadVersion::MaxVersion),
 
  /* Slots 0 and 2 are passengers and mail respectively for old saves. */
  SLEG_CONDVAR("supplied[CT_PASSENGERS].old_max", _old_pass_supplied[LAST_MONTH].production, VarFileType::U16 | VarMemType::U32, SaveLoadVersion::MinVersion, SaveLoadVersion::LargerTownCargoStatistics),
  SLEG_CONDVAR("supplied[CT_PASSENGERS].old_max", _old_pass_supplied[LAST_MONTH].production, VarTypes::U32, SaveLoadVersion::LargerTownCargoStatistics, SaveLoadVersion::ScriptTownGrowth),
  SLEG_CONDVAR( "supplied[CT_MAIL].old_max", _old_mail_supplied[LAST_MONTH].production, VarFileType::U16 | VarMemType::U32, SaveLoadVersion::MinVersion, SaveLoadVersion::LargerTownCargoStatistics),
  SLEG_CONDVAR( "supplied[CT_MAIL].old_max", _old_mail_supplied[LAST_MONTH].production, VarTypes::U32, SaveLoadVersion::LargerTownCargoStatistics, SaveLoadVersion::ScriptTownGrowth),
  SLEG_CONDVAR("supplied[CT_PASSENGERS].new_max", _old_pass_supplied[THIS_MONTH].production, VarFileType::U16 | VarMemType::U32, SaveLoadVersion::MinVersion, SaveLoadVersion::LargerTownCargoStatistics),
  SLEG_CONDVAR("supplied[CT_PASSENGERS].new_max", _old_pass_supplied[THIS_MONTH].production, VarTypes::U32, SaveLoadVersion::LargerTownCargoStatistics, SaveLoadVersion::ScriptTownGrowth),
  SLEG_CONDVAR( "supplied[CT_MAIL].new_max", _old_mail_supplied[THIS_MONTH].production, VarFileType::U16 | VarMemType::U32, SaveLoadVersion::MinVersion, SaveLoadVersion::LargerTownCargoStatistics),
  SLEG_CONDVAR( "supplied[CT_MAIL].new_max", _old_mail_supplied[THIS_MONTH].production, VarTypes::U32, SaveLoadVersion::LargerTownCargoStatistics, SaveLoadVersion::ScriptTownGrowth),
  SLEG_CONDVAR("supplied[CT_PASSENGERS].old_act", _old_pass_supplied[LAST_MONTH].transported, VarFileType::U16 | VarMemType::U32, SaveLoadVersion::MinVersion, SaveLoadVersion::LargerTownCargoStatistics),
  SLEG_CONDVAR("supplied[CT_PASSENGERS].old_act", _old_pass_supplied[LAST_MONTH].transported, VarTypes::U32, SaveLoadVersion::LargerTownCargoStatistics, SaveLoadVersion::ScriptTownGrowth),
  SLEG_CONDVAR( "supplied[CT_MAIL].old_act", _old_mail_supplied[LAST_MONTH].transported, VarFileType::U16 | VarMemType::U32, SaveLoadVersion::MinVersion, SaveLoadVersion::LargerTownCargoStatistics),
  SLEG_CONDVAR( "supplied[CT_MAIL].old_act", _old_mail_supplied[LAST_MONTH].transported, VarTypes::U32, SaveLoadVersion::LargerTownCargoStatistics, SaveLoadVersion::ScriptTownGrowth),
  SLEG_CONDVAR("supplied[CT_PASSENGERS].new_act", _old_pass_supplied[THIS_MONTH].transported, VarFileType::U16 | VarMemType::U32, SaveLoadVersion::MinVersion, SaveLoadVersion::LargerTownCargoStatistics),
  SLEG_CONDVAR("supplied[CT_PASSENGERS].new_act", _old_pass_supplied[THIS_MONTH].transported, VarTypes::U32, SaveLoadVersion::LargerTownCargoStatistics, SaveLoadVersion::ScriptTownGrowth),
  SLEG_CONDVAR( "supplied[CT_MAIL].new_act", _old_mail_supplied[THIS_MONTH].transported, VarFileType::U16 | VarMemType::U32, SaveLoadVersion::MinVersion, SaveLoadVersion::LargerTownCargoStatistics),
  SLEG_CONDVAR( "supplied[CT_MAIL].new_act", _old_mail_supplied[THIS_MONTH].transported, VarTypes::U32, SaveLoadVersion::LargerTownCargoStatistics, SaveLoadVersion::ScriptTownGrowth),
 
  SLE_CONDVARNAME(Town, received[TownAcceptanceEffect::Food].old_act, "received[TE_FOOD].old_act", VarTypes::U16, SaveLoadVersion::MinVersion, SaveLoadVersion::ScriptTownGrowth),
  SLE_CONDVARNAME(Town, received[TownAcceptanceEffect::Water].old_act, "received[TE_WATER].old_act", VarTypes::U16, SaveLoadVersion::MinVersion, SaveLoadVersion::ScriptTownGrowth),
  SLE_CONDVARNAME(Town, received[TownAcceptanceEffect::Food].new_act, "received[TE_FOOD].new_act", VarTypes::U16, SaveLoadVersion::MinVersion, SaveLoadVersion::ScriptTownGrowth),
  SLE_CONDVARNAME(Town, received[TownAcceptanceEffect::Water].new_act, "received[TE_WATER].new_act", VarTypes::U16, SaveLoadVersion::MinVersion, SaveLoadVersion::ScriptTownGrowth),
 
  SLE_CONDARR(Town, goal, VarTypes::U32, to_underlying(TownAcceptanceEffect::End), SaveLoadVersion::ScriptTownGrowth, SaveLoadVersion::MaxVersion),
 
  SLE_CONDSSTR(Town, text, VarTypes::STR | StringValidationSetting::AllowControlCode, SaveLoadVersion::ScriptTownText, SaveLoadVersion::MaxVersion),
 
  SLE_CONDVAR(Town, time_until_rebuild, VarFileType::U8 | VarMemType::U16, SaveLoadVersion::MinVersion, SaveLoadVersion::TownGrowthControl),
  SLE_CONDVAR(Town, time_until_rebuild, VarTypes::U16, SaveLoadVersion::TownGrowthControl, SaveLoadVersion::MaxVersion),
  SLE_CONDVAR(Town, grow_counter, VarFileType::U8 | VarMemType::U16, SaveLoadVersion::MinVersion, SaveLoadVersion::TownGrowthControl),
  SLE_CONDVAR(Town, grow_counter, VarTypes::U16, SaveLoadVersion::TownGrowthControl, SaveLoadVersion::MaxVersion),
  SLE_CONDVAR(Town, growth_rate, VarFileType::U8 | VarMemType::I16, SaveLoadVersion::MinVersion, SaveLoadVersion::TownGrowthControl),
  SLE_CONDVAR(Town, growth_rate, VarFileType::I16 | VarMemType::U16, SaveLoadVersion::TownGrowthControl, SaveLoadVersion::ScriptTownGrowth),
  SLE_CONDVAR(Town, growth_rate, VarTypes::U16, SaveLoadVersion::ScriptTownGrowth, SaveLoadVersion::MaxVersion),
 
      SLE_VAR(Town, fund_buildings_months, VarTypes::U8),
      SLE_VAR(Town, road_build_months,     VarTypes::U8),
 
  SLE_CONDVAR(Town, exclusivity, VarTypes::U8, SaveLoadVersion::VehicleCurrencyStationChanges, SaveLoadVersion::MaxVersion),
  SLE_CONDVAR(Town, exclusive_counter, VarTypes::U8, SaveLoadVersion::VehicleCurrencyStationChanges, SaveLoadVersion::MaxVersion),
 
  SLE_CONDVAR(Town, larger_town, VarTypes::BOOL, SaveLoadVersion::Cities, SaveLoadVersion::MaxVersion),
  SLE_CONDVAR(Town, layout, VarTypes::U8, SaveLoadVersion::RoadLayoutPerTown, SaveLoadVersion::MaxVersion),
  SLE_CONDVAR(Town, valid_history, VarTypes::U64, SaveLoadVersion::TownSupplyHistory, SaveLoadVersion::MaxVersion),
 
  SLE_CONDREFVECTOR(Town, psa_list, SLRefType::Storage, SaveLoadVersion::PersistentStoragePool, SaveLoadVersion::MaxVersion),
 
  SLEG_CONDSTRUCTLIST("supplied", SlTownOldSupplied, SaveLoadVersion::ScriptTownGrowth, SaveLoadVersion::TownSupplyHistory),
  SLEG_CONDSTRUCTLIST("supplied", SlTownSupplied, SaveLoadVersion::TownSupplyHistory, SaveLoadVersion::MaxVersion),
  SLEG_STRUCTLIST("accepted", SlTownAccepted),
  SLEG_CONDSTRUCTLIST("received", SlTownReceived, SaveLoadVersion::ScriptTownGrowth, SaveLoadVersion::MaxVersion),
  SLEG_CONDSTRUCTLIST("acceptance_matrix", SlTownAcceptanceMatrix, SaveLoadVersion::InfrastructureMaintenanceCosts, SaveLoadVersion::RemoveTownCargoCache),
};
 
struct HIDSChunkHandler : NewGRFMappingChunkHandler {
  HIDSChunkHandler() : NewGRFMappingChunkHandler('HIDS', _house_mngr) {}
};
 
struct CITYChunkHandler : ChunkHandler {
  CITYChunkHandler() : ChunkHandler('CITY', ChunkType::Table) {}
 
  void Save() const override
  {
    SlTableHeader(_town_desc);
 
    for (Town *t : Town::Iterate()) {
      SlSetArrayIndex(t->index);
      SlObject(t, _town_desc);
    }
  }
 
  void Load() const override
  {
    const std::vector<SaveLoad> slt = SlCompatTableHeader(_town_desc, _town_sl_compat);
 
    int index;
 
    while ((index = SlIterateArray()) != -1) {
      Town *t = Town::CreateAtIndex(TownID(index));
      SlObject(t, slt);
 
      if (IsSavegameVersionBefore(SaveLoadVersion::ScriptTownGrowth)) {
        /* Passengers and mail were always treated as slots 0 and 2 in older saves. */
        auto &pass = t->supplied.emplace_back(CargoType{0});
        pass.history[LAST_MONTH] = _old_pass_supplied[LAST_MONTH];
        pass.history[THIS_MONTH] = _old_pass_supplied[THIS_MONTH];
        auto &mail = t->supplied.emplace_back(CargoType{2});
        mail.history[LAST_MONTH] = _old_mail_supplied[LAST_MONTH];
        mail.history[THIS_MONTH] = _old_mail_supplied[THIS_MONTH];
      }
 
      if (IsSavegameVersionBefore(SaveLoadVersion::TownSupplyHistory)) {
        t->valid_history = 1U << LAST_MONTH;
      }
 
      if (t->townnamegrfid == 0 && !IsInsideMM(t->townnametype, SPECSTR_TOWNNAME_START, SPECSTR_TOWNNAME_END) && GetStringTab(t->townnametype) != TEXT_TAB_OLD_CUSTOM) {
        SlErrorCorrupt("Invalid town name generator");
      }
    }
  }
 
  void FixPointers() const override
  {
    if (IsSavegameVersionBefore(SaveLoadVersion::PersistentStoragePool)) return;
 
    for (Town *t : Town::Iterate()) {
      SlObject(t, _town_desc);
    }
  }
};
 
static const HIDSChunkHandler HIDS;
static const CITYChunkHandler CITY;
static const ChunkHandlerRef town_chunk_handlers[] = {
  HIDS,
  CITY,
};
 
extern const ChunkHandlerTable _town_chunk_handlers(town_chunk_handlers);