# ai_instance.cpp

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    00001 /* $Id: ai_instance.cpp 15708 2009-03-14 01:32:04Z yexo $ */
    00002
    00005 #include "../stdafx.h"
    00006 #include "../debug.h"
    00007 #include "../settings_type.h"
    00008 #include "../vehicle_base.h"
    00009 #include "../saveload/saveload.h"
    00010 #include "../gui.h"
    00011 #include "table/strings.h"
    00012
    00013 #include <squirrel.h>
    00014 #include "../script/squirrel.hpp"
    00015 #include "../script/squirrel_helper.hpp"
    00016 #include "../script/squirrel_class.hpp"
    00017 #include "../script/squirrel_std.hpp"
    00018
    00019 #define DEFINE_SCRIPT_FILES
    00020
    00021 #include "ai_info.hpp"
    00022 #include "ai_storage.hpp"
    00023 #include "ai_instance.hpp"
    00024 #include "ai_gui.hpp"
    00025
    00026 /* Convert all AI related classes to Squirrel data.
    00027  * Note: this line a marker in squirrel_export.sh. Do not change! */
    00028 #include "api/ai_abstractlist.hpp.sq"
    00029 #include "api/ai_accounting.hpp.sq"
    00030 #include "api/ai_airport.hpp.sq"
    00031 #include "api/ai_base.hpp.sq"
    00032 #include "api/ai_bridge.hpp.sq"
    00033 #include "api/ai_bridgelist.hpp.sq"
    00034 #include "api/ai_cargo.hpp.sq"
    00035 #include "api/ai_cargolist.hpp.sq"
    00036 #include "api/ai_company.hpp.sq"
    00037 #include "api/ai_controller.hpp.sq"
    00038 #include "api/ai_date.hpp.sq"
    00039 #include "api/ai_depotlist.hpp.sq"
    00040 #include "api/ai_engine.hpp.sq"
    00041 #include "api/ai_enginelist.hpp.sq"
    00042 #include "api/ai_error.hpp.sq"
    00043 #include "api/ai_event.hpp.sq"
    00044 #include "api/ai_event_types.hpp.sq"
    00045 #include "api/ai_execmode.hpp.sq"
    00046 #include "api/ai_gamesettings.hpp.sq"
    00047 #include "api/ai_group.hpp.sq"
    00048 #include "api/ai_grouplist.hpp.sq"
    00049 #include "api/ai_industry.hpp.sq"
    00050 #include "api/ai_industrylist.hpp.sq"
    00051 #include "api/ai_industrytype.hpp.sq"
    00052 #include "api/ai_industrytypelist.hpp.sq"
    00053 #include "api/ai_list.hpp.sq"
    00054 #include "api/ai_log.hpp.sq"
    00055 #include "api/ai_map.hpp.sq"
    00056 #include "api/ai_marine.hpp.sq"
    00057 #include "api/ai_order.hpp.sq"
    00058 #include "api/ai_rail.hpp.sq"
    00059 #include "api/ai_railtypelist.hpp.sq"
    00060 #include "api/ai_road.hpp.sq"
    00061 #include "api/ai_sign.hpp.sq"
    00062 #include "api/ai_station.hpp.sq"
    00063 #include "api/ai_stationlist.hpp.sq"
    00064 #include "api/ai_subsidy.hpp.sq"
    00065 #include "api/ai_subsidylist.hpp.sq"
    00066 #include "api/ai_testmode.hpp.sq"
    00067 #include "api/ai_tile.hpp.sq"
    00068 #include "api/ai_tilelist.hpp.sq"
    00069 #include "api/ai_town.hpp.sq"
    00070 #include "api/ai_townlist.hpp.sq"
    00071 #include "api/ai_tunnel.hpp.sq"
    00072 #include "api/ai_vehicle.hpp.sq"
    00073 #include "api/ai_vehiclelist.hpp.sq"
    00074 #include "api/ai_waypoint.hpp.sq"
    00075 #include "api/ai_waypointlist.hpp.sq"
    00076
    00077 #undef DEFINE_SCRIPT_FILES
    00078
    00079 /* static */ AIInstance *AIInstance::current_instance = NULL;
    00080
    00081 AIStorage::~AIStorage()
    00082 {
    00083   /* Free our pointers */
    00084   if (event_data != NULL) AIEventController::FreeEventPointer();
    00085   if (log_data != NULL) AILog::FreeLogPointer();
    00086 }
    00087
    00088 static void PrintFunc(bool error_msg, const SQChar *message)
    00089 {
    00090   /* Convert to OpenTTD internal capable string */
    00091   AIController::Print(error_msg, FS2OTTD(message));
    00092 }
    00093
    00094 AIInstance::AIInstance(AIInfo *info) :
    00095   controller(NULL),
    00096   storage(NULL),
    00097   engine(NULL),
    00098   instance(NULL),
    00099   is_started(false),
    00100   is_dead(false),
    00101   suspend(0),
    00102   callback(NULL)
    00103 {
    00104   /* Set the instance already, so we can use AIObject::Set commands */
    00105   GetCompany(_current_company)->ai_instance = this;
    00106   AIInstance::current_instance = this;
    00107
    00108   this->controller = new AIController();
    00109   this->storage    = new AIStorage();
    00110   this->engine     = new Squirrel();
    00111   this->engine->SetPrintFunction(&PrintFunc);
    00112
    00113   /* The import method is available at a very early stage */
    00114   this->engine->AddMethod("import", &AILibrary::Import, 4, ".ssi");
    00115
    00116   /* Register the AIController */
    00117   SQAIController_Register(this->engine);
    00118
    00119   /* Load and execute the script for this AI */
    00120   const char *main_script = info->GetMainScript();
    00121   if (strcmp(main_script, "%_dummy") == 0) {
    00122     extern void AI_CreateAIDummy(HSQUIRRELVM vm);
    00123     AI_CreateAIDummy(this->engine->GetVM());
    00124   } else if (!this->engine->LoadScript(main_script)) {
    00125     this->Died();
    00126     return;
    00127   }
    00128
    00129   /* Create the main-class */
    00130   this->instance = MallocT<SQObject>(1);
    00131   if (!this->engine->CreateClassInstance(info->GetInstanceName(), this->controller, this->instance)) {
    00132     this->Died();
    00133     return;
    00134   }
    00135
    00136   /* Register the API functions and classes */
    00137   this->RegisterAPI();
    00138
    00139   /* The topmost stack item is true if there is data from a savegame
    00140    * and false otherwise. */
    00141   sq_pushbool(this->engine->vm, false);
    00142 }
    00143
    00144 AIInstance::~AIInstance()
    00145 {
    00146   if (instance != NULL) this->engine->ReleaseObject(this->instance);
    00147   if (engine != NULL) delete this->engine;
    00148   delete this->storage;
    00149   delete this->controller;
    00150   free(this->instance);
    00151 }
    00152
    00153 void AIInstance::RegisterAPI()
    00154 {
    00155 /* Register all classes */
    00156   squirrel_register_std(this->engine);
    00157   SQAIAbstractList_Register(this->engine);
    00158   SQAIAccounting_Register(this->engine);
    00159   SQAIAirport_Register(this->engine);
    00160   SQAIBase_Register(this->engine);
    00161   SQAIBridge_Register(this->engine);
    00162   SQAIBridgeList_Register(this->engine);
    00163   SQAIBridgeList_Length_Register(this->engine);
    00164   SQAICargo_Register(this->engine);
    00165   SQAICargoList_Register(this->engine);
    00166   SQAICargoList_IndustryAccepting_Register(this->engine);
    00167   SQAICargoList_IndustryProducing_Register(this->engine);
    00168   SQAICompany_Register(this->engine);
    00169   SQAIDate_Register(this->engine);
    00170   SQAIDepotList_Register(this->engine);
    00171   SQAIEngine_Register(this->engine);
    00172   SQAIEngineList_Register(this->engine);
    00173   SQAIError_Register(this->engine);
    00174   SQAIEvent_Register(this->engine);
    00175   SQAIEventCompanyBankrupt_Register(this->engine);
    00176   SQAIEventCompanyInTrouble_Register(this->engine);
    00177   SQAIEventCompanyMerger_Register(this->engine);
    00178   SQAIEventCompanyNew_Register(this->engine);
    00179   SQAIEventController_Register(this->engine);
    00180   SQAIEventDisasterZeppelinerCleared_Register(this->engine);
    00181   SQAIEventDisasterZeppelinerCrashed_Register(this->engine);
    00182   SQAIEventEngineAvailable_Register(this->engine);
    00183   SQAIEventEnginePreview_Register(this->engine);
    00184   SQAIEventIndustryClose_Register(this->engine);
    00185   SQAIEventIndustryOpen_Register(this->engine);
    00186   SQAIEventStationFirstVehicle_Register(this->engine);
    00187   SQAIEventSubsidyAwarded_Register(this->engine);
    00188   SQAIEventSubsidyExpired_Register(this->engine);
    00189   SQAIEventSubsidyOffer_Register(this->engine);
    00190   SQAIEventSubsidyOfferExpired_Register(this->engine);
    00191   SQAIEventVehicleCrashed_Register(this->engine);
    00192   SQAIEventVehicleLost_Register(this->engine);
    00193   SQAIEventVehicleUnprofitable_Register(this->engine);
    00194   SQAIEventVehicleWaitingInDepot_Register(this->engine);
    00195   SQAIExecMode_Register(this->engine);
    00196   SQAIGameSettings_Register(this->engine);
    00197   SQAIGroup_Register(this->engine);
    00198   SQAIGroupList_Register(this->engine);
    00199   SQAIIndustry_Register(this->engine);
    00200   SQAIIndustryList_Register(this->engine);
    00201   SQAIIndustryList_CargoAccepting_Register(this->engine);
    00202   SQAIIndustryList_CargoProducing_Register(this->engine);
    00203   SQAIIndustryType_Register(this->engine);
    00204   SQAIIndustryTypeList_Register(this->engine);
    00205   SQAIList_Register(this->engine);
    00206   SQAILog_Register(this->engine);
    00207   SQAIMap_Register(this->engine);
    00208   SQAIMarine_Register(this->engine);
    00209   SQAIOrder_Register(this->engine);
    00210   SQAIRail_Register(this->engine);
    00211   SQAIRailTypeList_Register(this->engine);
    00212   SQAIRoad_Register(this->engine);
    00213   SQAISign_Register(this->engine);
    00214   SQAIStation_Register(this->engine);
    00215   SQAIStationList_Register(this->engine);
    00216   SQAIStationList_Vehicle_Register(this->engine);
    00217   SQAISubsidy_Register(this->engine);
    00218   SQAISubsidyList_Register(this->engine);
    00219   SQAITestMode_Register(this->engine);
    00220   SQAITile_Register(this->engine);
    00221   SQAITileList_Register(this->engine);
    00222   SQAITileList_IndustryAccepting_Register(this->engine);
    00223   SQAITileList_IndustryProducing_Register(this->engine);
    00224   SQAITileList_StationType_Register(this->engine);
    00225   SQAITown_Register(this->engine);
    00226   SQAITownList_Register(this->engine);
    00227   SQAITunnel_Register(this->engine);
    00228   SQAIVehicle_Register(this->engine);
    00229   SQAIVehicleList_Register(this->engine);
    00230   SQAIVehicleList_DefaultGroup_Register(this->engine);
    00231   SQAIVehicleList_Group_Register(this->engine);
    00232   SQAIVehicleList_SharedOrders_Register(this->engine);
    00233   SQAIVehicleList_Station_Register(this->engine);
    00234   SQAIWaypoint_Register(this->engine);
    00235   SQAIWaypointList_Register(this->engine);
    00236   SQAIWaypointList_Vehicle_Register(this->engine);
    00237
    00238   this->engine->SetGlobalPointer(this->engine);
    00239 }
    00240
    00241 void AIInstance::Continue()
    00242 {
    00243   assert(this->suspend < 0);
    00244   this->suspend = -this->suspend - 1;
    00245 }
    00246
    00247 void AIInstance::Died()
    00248 {
    00249   DEBUG(ai, 0, "The AI died unexpectedly.");
    00250   this->is_dead = true;
    00251
    00252   if (this->instance != NULL) this->engine->ReleaseObject(this->instance);
    00253   delete this->engine;
    00254   this->instance = NULL;
    00255   this->engine = NULL;
    00256
    00257   ShowAIDebugWindow(_current_company);
    00258   ShowErrorMessage(INVALID_STRING_ID, STR_AI_PLEASE_REPORT_CRASH, 0, 0);
    00259 }
    00260
    00261 void AIInstance::GameLoop()
    00262 {
    00263   if (this->is_dead) return;
    00264   if (this->engine->HasScriptCrashed()) {
    00265     /* The script crashed during saving, kill it here. */
    00266     this->Died();
    00267     return;
    00268   }
    00269   this->controller->ticks++;
    00270
    00271   if (this->suspend   < -1) this->suspend++; // Multiplayer suspend, increase up to -1.
    00272   if (this->suspend   < 0)  return;          // Multiplayer suspend, wait for Continue().
    00273   if (--this->suspend > 0)  return;          // Singleplayer suspend, decrease to 0.
    00274
    00275   /* If there is a callback to call, call that first */
    00276   if (this->callback != NULL) {
    00277     try {
    00278       this->callback(this);
    00279     } catch (AI_VMSuspend e) {
    00280       this->suspend  = e.GetSuspendTime();
    00281       this->callback = e.GetSuspendCallback();
    00282
    00283       return;
    00284     }
    00285   }
    00286
    00287   this->suspend  = 0;
    00288   this->callback = NULL;
    00289
    00290   if (!this->is_started) {
    00291     try {
    00292       AIObject::SetAllowDoCommand(false);
    00293       /* Run the constructor if it exists. Don't allow any DoCommands in it. */
    00294       if (this->engine->MethodExists(*this->instance, "constructor")) {
    00295         if (!this->engine->CallMethod(*this->instance, "constructor")) { this->Died(); return; }
    00296       }
    00297       if (!this->CallLoad()) { this->Died(); return; }
    00298       AIObject::SetAllowDoCommand(true);
    00299       /* Start the AI by calling Start() */
    00300       if (!this->engine->CallMethod(*this->instance, "Start",  _settings_game.ai.ai_max_opcode_till_suspend) || !this->engine->IsSuspended()) this->Died();
    00301     } catch (AI_VMSuspend e) {
    00302       this->suspend  = e.GetSuspendTime();
    00303       this->callback = e.GetSuspendCallback();
    00304     }
    00305
    00306     this->is_started = true;
    00307     return;
    00308   }
    00309
    00310   /* Continue the VM */
    00311   try {
    00312     if (!this->engine->Resume(_settings_game.ai.ai_max_opcode_till_suspend)) this->Died();
    00313   } catch (AI_VMSuspend e) {
    00314     this->suspend  = e.GetSuspendTime();
    00315     this->callback = e.GetSuspendCallback();
    00316   }
    00317 }
    00318
    00319 void AIInstance::CollectGarbage()
    00320 {
    00321   if (this->is_started && !this->is_dead) this->engine->CollectGarbage();
    00322 }
    00323
    00324 /* static */ void AIInstance::DoCommandReturn(AIInstance *instance)
    00325 {
    00326   instance->engine->InsertResult(AIObject::GetLastCommandRes());
    00327 }
    00328
    00329 /* static */ void AIInstance::DoCommandReturnVehicleID(AIInstance *instance)
    00330 {
    00331   instance->engine->InsertResult(AIObject::GetNewVehicleID());
    00332 }
    00333
    00334 /* static */ void AIInstance::DoCommandReturnSignID(AIInstance *instance)
    00335 {
    00336   instance->engine->InsertResult(AIObject::GetNewSignID());
    00337 }
    00338
    00339 /* static */ void AIInstance::DoCommandReturnGroupID(AIInstance *instance)
    00340 {
    00341   instance->engine->InsertResult(AIObject::GetNewGroupID());
    00342 }
    00343
    00344 /* static */ AIStorage *AIInstance::GetStorage()
    00345 {
    00346   assert(IsValidCompanyID(_current_company) && !IsHumanCompany(_current_company));
    00347   return GetCompany(_current_company)->ai_instance->storage;
    00348 }
    00349
    00350 /*
    00351  * All data is stored in the following format:
    00352  * First 1 byte indicating if there is a data blob at all.
    00353  * 1 byte indicating the type of data.
    00354  * The data itself, this differs per type:
    00355  *  - integer: a binary representation of the integer (int32).
    00356  *  - string:  First one byte with the string length, then a 0-terminated char
    00357  *             array. The string can't be longer then 255 bytes (including
    00358  *             terminating '\0').
    00359  *  - array:   All data-elements of the array are saved recursive in this
    00360  *             format, and ended with an element of the type
    00361  *             SQSL_ARRAY_TABLE_END.
    00362  *  - table:   All key/value pairs are saved in this format (first key 1, then
    00363  *             value 1, then key 2, etc.). All keys and values can have an
    00364  *             arbitrary type (as long as it is supported by the save function
    00365  *             of course). The table is ended with an element of the type
    00366  *             SQSL_ARRAY_TABLE_END.
    00367  *  - bool:    A single byte with value 1 representing true and 0 false.
    00368  *  - null:    No data.
    00369  */
    00370
    00372 enum SQSaveLoadType {
    00373   SQSL_INT             = 0x00,
    00374   SQSL_STRING          = 0x01,
    00375   SQSL_ARRAY           = 0x02,
    00376   SQSL_TABLE           = 0x03,
    00377   SQSL_BOOL            = 0x04,
    00378   SQSL_NULL            = 0x05,
    00379   SQSL_ARRAY_TABLE_END = 0xFF,
    00380 };
    00381
    00382 static byte _ai_sl_byte;
    00383
    00384 static const SaveLoad _ai_byte[] = {
    00385   SLEG_VAR(_ai_sl_byte, SLE_UINT8),
    00386   SLE_END()
    00387 };
    00388
    00389 enum {
    00390   AISAVE_MAX_DEPTH = 25,
    00391 };
    00392
    00393 /* static */ bool AIInstance::SaveObject(HSQUIRRELVM vm, SQInteger index, int max_depth, bool test)
    00394 {
    00395   if (max_depth == 0) {
    00396     AILog::Error("Savedata can only be nested to 25 deep. No data saved.");
    00397     return false;
    00398   }
    00399
    00400   switch (sq_gettype(vm, index)) {
    00401     case OT_INTEGER: {
    00402       if (!test) {
    00403         _ai_sl_byte = SQSL_INT;
    00404         SlObject(NULL, _ai_byte);
    00405       }
    00406       SQInteger res;
    00407       sq_getinteger(vm, index, &res);
    00408       if (!test) {
    00409         int value = (int)res;
    00410         SlArray(&value, 1, SLE_INT32);
    00411       }
    00412       return true;
    00413     }
    00414
    00415     case OT_STRING: {
    00416       if (!test) {
    00417         _ai_sl_byte = SQSL_STRING;
    00418         SlObject(NULL, _ai_byte);
    00419       }
    00420       const SQChar *res;
    00421       sq_getstring(vm, index, &res);
    00422       /* @bug if a string longer than 512 characters is given to FS2OTTD, the
    00423        *  internal buffer overflows. */
    00424       const char *buf = FS2OTTD(res);
    00425       size_t len = strlen(buf) + 1;
    00426       if (len >= 255) {
    00427         AILog::Error("Maximum string length is 254 chars. No data saved.");
    00428         return false;
    00429       }
    00430       if (!test) {
    00431         _ai_sl_byte = (byte)len;
    00432         SlObject(NULL, _ai_byte);
    00433         SlArray((void*)buf, len, SLE_CHAR);
    00434       }
    00435       return true;
    00436     }
    00437
    00438     case OT_ARRAY: {
    00439       if (!test) {
    00440         _ai_sl_byte = SQSL_ARRAY;
    00441         SlObject(NULL, _ai_byte);
    00442       }
    00443       sq_pushnull(vm);
    00444       while (SQ_SUCCEEDED(sq_next(vm, index - 1))) {
    00445         /* Store the value */
    00446         bool res = SaveObject(vm, -1, max_depth - 1, test);
    00447         sq_pop(vm, 2);
    00448         if (!res) {
    00449           sq_pop(vm, 1);
    00450           return false;
    00451         }
    00452       }
    00453       sq_pop(vm, 1);
    00454       if (!test) {
    00455         _ai_sl_byte = SQSL_ARRAY_TABLE_END;
    00456         SlObject(NULL, _ai_byte);
    00457       }
    00458       return true;
    00459     }
    00460
    00461     case OT_TABLE: {
    00462       if (!test) {
    00463         _ai_sl_byte = SQSL_TABLE;
    00464         SlObject(NULL, _ai_byte);
    00465       }
    00466       sq_pushnull(vm);
    00467       while (SQ_SUCCEEDED(sq_next(vm, index - 1))) {
    00468         /* Store the key + value */
    00469         bool res = SaveObject(vm, -2, max_depth - 1, test) && SaveObject(vm, -1, max_depth - 1, test);
    00470         sq_pop(vm, 2);
    00471         if (!res) {
    00472           sq_pop(vm, 1);
    00473           return false;
    00474         }
    00475       }
    00476       sq_pop(vm, 1);
    00477       if (!test) {
    00478         _ai_sl_byte = SQSL_ARRAY_TABLE_END;
    00479         SlObject(NULL, _ai_byte);
    00480       }
    00481       return true;
    00482     }
    00483
    00484     case OT_BOOL: {
    00485       if (!test) {
    00486         _ai_sl_byte = SQSL_BOOL;
    00487         SlObject(NULL, _ai_byte);
    00488       }
    00489       SQBool res;
    00490       sq_getbool(vm, index, &res);
    00491       if (!test) {
    00492         _ai_sl_byte = res ? 1 : 0;
    00493         SlObject(NULL, _ai_byte);
    00494       }
    00495       return true;
    00496     }
    00497
    00498     case OT_NULL: {
    00499       if (!test) {
    00500         _ai_sl_byte = SQSL_NULL;
    00501         SlObject(NULL, _ai_byte);
    00502       }
    00503       return true;
    00504     }
    00505
    00506     default:
    00507       AILog::Error("You tried to save an unsupported type. No data saved.");
    00508       return false;
    00509   }
    00510 }
    00511
    00512 /* static */ void AIInstance::SaveEmpty()
    00513 {
    00514   _ai_sl_byte = 0;
    00515   SlObject(NULL, _ai_byte);
    00516 }
    00517
    00518 void AIInstance::Save()
    00519 {
    00520   /* Don't save data if the AI didn't start yet or if it crashed. */
    00521   if (this->engine == NULL || this->engine->HasScriptCrashed()) {
    00522     SaveEmpty();
    00523     return;
    00524   }
    00525
    00526   HSQUIRRELVM vm = this->engine->GetVM();
    00527   if (!this->is_started) {
    00528     SQBool res;
    00529     sq_getbool(vm, -1, &res);
    00530     if (!res) {
    00531       SaveEmpty();
    00532       return;
    00533     }
    00534     /* Push the loaded savegame data to the top of the stack. */
    00535     sq_push(vm, -2);
    00536     _ai_sl_byte = 1;
    00537     SlObject(NULL, _ai_byte);
    00538     /* Save the data that was just loaded. */
    00539     SaveObject(vm, -1, AISAVE_MAX_DEPTH, false);
    00540     sq_poptop(vm);
    00541   } else if (this->engine->MethodExists(*this->instance, "Save")) {
    00542     HSQOBJECT savedata;
    00543     /* We don't want to be interrupted during the save function. */
    00544     bool backup_allow = AIObject::GetAllowDoCommand();
    00545     AIObject::SetAllowDoCommand(false);
    00546     if (!this->engine->CallMethod(*this->instance, "Save", &savedata)) {
    00547       /* The script crashed in the Save function. We can't kill
    00548        * it here, but do so in the next AI tick. */
    00549       SaveEmpty();
    00550       return;
    00551     }
    00552     AIObject::SetAllowDoCommand(backup_allow);
    00553
    00554     if (!sq_istable(savedata)) {
    00555       AILog::Error("Save function should return a table.");
    00556       SaveEmpty();
    00557       return;
    00558     }
    00559     sq_pushobject(vm, savedata);
    00560     if (SaveObject(vm, -1, AISAVE_MAX_DEPTH, true)) {
    00561       _ai_sl_byte = 1;
    00562       SlObject(NULL, _ai_byte);
    00563       SaveObject(vm, -1, AISAVE_MAX_DEPTH, false);
    00564     } else {
    00565       _ai_sl_byte = 0;
    00566       SlObject(NULL, _ai_byte);
    00567     }
    00568     sq_pop(vm, 1);
    00569   } else {
    00570     AILog::Warning("Save function is not implemented");
    00571     _ai_sl_byte = 0;
    00572     SlObject(NULL, _ai_byte);
    00573   }
    00574
    00575 }
    00576
    00577 /* static */ bool AIInstance::LoadObjects(HSQUIRRELVM vm)
    00578 {
    00579   SlObject(NULL, _ai_byte);
    00580   switch (_ai_sl_byte) {
    00581     case SQSL_INT: {
    00582       int value;
    00583       SlArray(&value, 1, SLE_INT32);
    00584       if (vm != NULL) sq_pushinteger(vm, (SQInteger)value);
    00585       return true;
    00586     }
    00587
    00588     case SQSL_STRING: {
    00589       SlObject(NULL, _ai_byte);
    00590       static char buf[256];
    00591       SlArray(buf, _ai_sl_byte, SLE_CHAR);
    00592       if (vm != NULL) sq_pushstring(vm, OTTD2FS(buf), -1);
    00593       return true;
    00594     }
    00595
    00596     case SQSL_ARRAY: {
    00597       if (vm != NULL) sq_newarray(vm, 0);
    00598       while (LoadObjects(vm)) {
    00599         if (vm != NULL) sq_arrayappend(vm, -2);
    00600         /* The value is popped from the stack by squirrel. */
    00601       }
    00602       return true;
    00603     }
    00604
    00605     case SQSL_TABLE: {
    00606       if (vm != NULL) sq_newtable(vm);
    00607       while (LoadObjects(vm)) {
    00608         LoadObjects(vm);
    00609         if (vm != NULL) sq_rawset(vm, -3);
    00610         /* The key (-2) and value (-1) are popped from the stack by squirrel. */
    00611       }
    00612       return true;
    00613     }
    00614
    00615     case SQSL_BOOL: {
    00616       SlObject(NULL, _ai_byte);
    00617       if (vm != NULL) sq_pushinteger(vm, (SQBool)(_ai_sl_byte != 0));
    00618       return true;
    00619     }
    00620
    00621     case SQSL_NULL: {
    00622       if (vm != NULL) sq_pushnull(vm);
    00623       return true;
    00624     }
    00625
    00626     case SQSL_ARRAY_TABLE_END: {
    00627       return false;
    00628     }
    00629
    00630     default: NOT_REACHED();
    00631   }
    00632 }
    00633
    00634 /* static */ void AIInstance::LoadEmpty()
    00635 {
    00636   SlObject(NULL, _ai_byte);
    00637   /* Check if there was anything saved at all. */
    00638   if (_ai_sl_byte == 0) return;
    00639
    00640   LoadObjects(NULL);
    00641 }
    00642
    00643 void AIInstance::Load(int version)
    00644 {
    00645   if (this->engine == NULL || version == -1) {
    00646     LoadEmpty();
    00647     return;
    00648   }
    00649   HSQUIRRELVM vm = this->engine->GetVM();
    00650
    00651   SlObject(NULL, _ai_byte);
    00652   /* Check if there was anything saved at all. */
    00653   if (_ai_sl_byte == 0) return;
    00654
    00655   /* First remove the value "false" since we have data to load. */
    00656   sq_poptop(vm);
    00657   sq_pushinteger(vm, version);
    00658   LoadObjects(vm);
    00659   sq_pushbool(vm, true);
    00660 }
    00661
    00662 bool AIInstance::CallLoad()
    00663 {
    00664   HSQUIRRELVM vm = this->engine->GetVM();
    00665   /* Is there save data that we should load? */
    00666   SQBool res;
    00667   sq_getbool(vm, -1, &res);
    00668   sq_poptop(vm);
    00669   if (!res) return true;
    00670
    00671   if (!this->engine->MethodExists(*this->instance, "Load")) {
    00672     AILog::Warning("Loading failed: there was data for the AI to load, but the AI does not have a Load() function.");
    00673
    00674     /* Pop the savegame data and version. */
    00675     sq_pop(vm, 2);
    00676     return true;
    00677   }
    00678
    00679   /* Go to the instance-root */
    00680   sq_pushobject(vm, *this->instance);
    00681   /* Find the function-name inside the script */
    00682   sq_pushstring(vm, OTTD2FS("Load"), -1);
    00683   /* Change the "Load" string in a function pointer */
    00684   sq_get(vm, -2);
    00685   /* Push the main instance as "this" object */
    00686   sq_pushobject(vm, *this->instance);
    00687   /* Push the version data and savegame data as arguments */
    00688   sq_push(vm, -5);
    00689   sq_push(vm, -5);
    00690
    00691   /* Call the AI load function. sq_call removes the arguments (but not the
    00692    * function pointer) from the stack. */
    00693   if (SQ_FAILED(sq_call(vm, 3, SQFalse, SQFalse))) return false;
    00694
    00695   /* Pop 1) The version, 2) the savegame data, 3) the object instance, 4) the function pointer. */
    00696   sq_pop(vm, 4);
    00697   return true;
    00698 }