(svn r3396) - Autoreplace changes:

  - Change fixed array per player to a single pool. This avoids future problems
    with vehicle numbers and decreases savegame size. Engine replacements from
    previous savegames will be lost.
  - Move engine replacement code from players.c to engine.c.
                                      (thanks to blathijs for rewriting this)

12 files changed, 360 insertions, 116 deletions

diff --git a/aircraft_cmd.c b/aircraft_cmd.c
index 710ca24d5..668174314 100644
--- a/aircraft_cmd.c
+++ b/aircraft_cmd.c
@@ -1450,7 +1450,7 @@ static void AircraftEventHandler_HeliTakeOff(Vehicle *v, const AirportFTAClass *
 
 	// check if the aircraft needs to be replaced or renewed and send it to a hangar if needed
 	if (v->owner == _local_player && (
-				EngineHasReplacement(p, v->engine_type) ||
+				EngineHasReplacementForPlayer(p, v->engine_type) ||
 				(p->engine_renew && v->age - v->max_age > p->engine_renew_months * 30)
 			)) {
 		_current_player = _local_player;
@@ -1514,7 +1514,7 @@ static void AircraftEventHandler_Landing(Vehicle *v, const AirportFTAClass *Airp
 	// check if the aircraft needs to be replaced or renewed and send it to a hangar if needed
 	if (v->current_order.type != OT_GOTO_DEPOT && v->owner == _local_player) {
 		// only the vehicle owner needs to calculate the rest (locally)
-		if (EngineHasReplacement(p, v->engine_type) ||
+		if (EngineHasReplacementForPlayer(p, v->engine_type) ||
 			(p->engine_renew && v->age - v->max_age > (p->engine_renew_months * 30))) {
 			// send the aircraft to the hangar at next airport (bit 17 set)
 			_current_player = _local_player;
diff --git a/engine.c b/engine.c
index a2e717f1e..56693a00c 100644
--- a/engine.c
+++ b/engine.c
@@ -1051,6 +1051,195 @@ int32 CmdRenameEngine(int x, int y, uint32 flags, uint32 p1, uint32 p2)
 }
 
 
+/*
+ * returns true if an engine is valid, of the specified type, and buildable by
+ * the current player, false otherwise
+ *
+ * engine = index of the engine to check
+ * type   = the type the engine should be of (VEH_xxx)
+ */
+bool IsEngineBuildable(uint engine, byte type)
+{
+	const Engine *e;
+
+	// check if it's an engine that is in the engine array
+	if (!IsEngineIndex(engine)) return false;
+
+	e = GetEngine(engine);
+
+	// check if it's an engine of specified type
+	if (e->type != type) return false;
+
+	// check if it's available
+	if (!HASBIT(e->player_avail, _current_player)) return false;
+
+	return true;
+}
+
+/************************************************************************
+ * Engine Replacement stuff
+ ************************************************************************/
+
+static void EngineRenewPoolNewBlock(uint start_item); /* Forward declare for initializer of _engine_renew_pool */
+enum {
+	ENGINE_RENEW_POOL_BLOCK_SIZE_BITS = 3,
+	ENGINE_RENEW_POOL_MAX_BLOCKS      = 8000,
+};
+
+MemoryPool _engine_renew_pool = { "EngineRe", ENGINE_RENEW_POOL_MAX_BLOCKS, ENGINE_RENEW_POOL_BLOCK_SIZE_BITS, sizeof(EngineRenew), &EngineRenewPoolNewBlock, 0, 0, NULL };
+
+static inline uint16 GetEngineRenewPoolSize(void)
+{
+	return _engine_renew_pool.total_items;
+}
+
+#define FOR_ALL_ENGINE_RENEWS_FROM(er, start) for (er = GetEngineRenew(start); er != NULL; er = (er->index + 1 < GetEngineRenewPoolSize()) ? GetEngineRenew(er->index + 1) : NULL)
+#define FOR_ALL_ENGINE_RENEWS(er) FOR_ALL_ENGINE_RENEWS_FROM(er, 0)
+
+static void EngineRenewPoolNewBlock(uint start_item)
+{
+	EngineRenew *er;
+
+	FOR_ALL_ENGINE_RENEWS_FROM(er, start_item) {
+		er->index = start_item++;
+		er->from = INVALID_ENGINE;
+	}
+}
+
+
+static EngineRenew *AllocateEngineRenew(void)
+{
+	EngineRenew *er;
+
+	FOR_ALL_ENGINE_RENEWS(er) {
+		if (er->from == INVALID_ENGINE) {
+			er->to = INVALID_ENGINE;
+			er->next = NULL;
+			return er;
+		}
+	}
+
+	/* Check if we can add a block to the pool */
+	if (AddBlockToPool(&_engine_renew_pool)) return AllocateEngineRenew();
+
+	return NULL;
+}
+
+/**
+ * Retrieves the EngineRenew that specifies the replacement of the given
+ * engine type from the given renewlist */
+static EngineRenew *GetEngineReplacement(EngineRenewList erl, EngineID engine)
+{
+	EngineRenew* er = (EngineRenew*)erl; /* Fetch first element */
+	while (er) {
+		if (er->from == engine) return er;
+		er = er->next;
+	}
+	return NULL;
+}
+
+void RemoveAllEngineReplacement(EngineRenewList* erl)
+{
+	EngineRenew* er = (EngineRenew*)(*erl); /* Fetch first element */
+	while (er) {
+		er->from = INVALID_ENGINE; /* "Deallocate" all elements */
+		er = er->next;
+	}
+	*erl = NULL; /* Empty list */
+}
+
+EngineID EngineReplacement(EngineRenewList erl, EngineID engine)
+{
+	const EngineRenew *er = GetEngineReplacement(erl, engine);
+	return er == NULL ? INVALID_ENGINE : er->to;
+}
+
+int32 AddEngineReplacement(EngineRenewList* erl, EngineID old_engine, EngineID new_engine, uint32 flags)
+{
+	EngineRenew *er;
+
+	// Check if the old vehicle is already in the list
+	er = GetEngineReplacement(*erl, old_engine);
+	if (er != NULL) {
+		if (flags & DC_EXEC) er->to = new_engine;
+		return 0;
+	}
+
+	er = AllocateEngineRenew();
+	if (er == NULL) return CMD_ERROR;
+
+	if (flags & DC_EXEC) {
+		er->from = old_engine;
+		er->to = new_engine;
+		er->next = (EngineRenew*)(*erl); /* Resolve the first element in the list */
+
+		*erl = (EngineRenewList)er; /* Insert before the first element */
+	}
+
+	return 0;
+}
+
+int32 RemoveEngineReplacement(EngineRenewList* erl, EngineID engine, uint32 flags)
+{
+	EngineRenew* er = (EngineRenew*)(*erl); /* Start at the first element */
+	EngineRenew* prev = NULL;
+
+	while (er)
+	{
+		if (er->from == engine) {
+			if (flags & DC_EXEC) {
+				if (prev == NULL) { /* First element */
+					(*erl) = (EngineRenewList)er->next; /* The second becomes the new first element */
+				} else {
+					prev->next = er->next; /* Cut this element out */
+				}
+				er->from = INVALID_ENGINE; /* Deallocate */
+			}
+			return 0;
+		}
+		prev = er;
+		er = er->next; /* Look at next element */
+	}
+
+	return CMD_ERROR; /* Not found? */
+}
+
+static const SaveLoad _engine_renew_desc[] = {
+	SLE_VAR(EngineRenew, from, SLE_UINT16),
+	SLE_VAR(EngineRenew, to,   SLE_UINT16),
+
+	SLE_REF(EngineRenew, next, REF_ENGINE_RENEWS),
+
+	SLE_END()
+};
+
+static void Save_ERNW(void)
+{
+	EngineRenew *er;
+
+	FOR_ALL_ENGINE_RENEWS(er) {
+		if (er->from != INVALID_ENGINE) {
+			SlSetArrayIndex(er->index);
+			SlObject(er, _engine_renew_desc);
+		}
+	}
+}
+
+static void Load_ERNW(void)
+{
+	int index;
+
+	while ((index = SlIterateArray()) != -1) {
+		EngineRenew *er;
+
+		if (!AddBlockIfNeeded(&_engine_renew_pool, index))
+			error("EngineRenews: failed loading savegame: too many EngineRenews");
+
+		er = GetEngineRenew(index);
+		SlObject(er, _engine_renew_desc);
+	}
+}
+
 static const SaveLoad _engine_desc[] = {
 	SLE_VAR(Engine,intro_date,						SLE_UINT16),
 	SLE_VAR(Engine,age,										SLE_UINT16),
@@ -1100,32 +1289,14 @@ static void LoadSave_ENGS(void)
 }
 
 const ChunkHandler _engine_chunk_handlers[] = {
-	{ 'ENGN', Save_ENGN, Load_ENGN, CH_ARRAY},
-	{ 'ENGS', LoadSave_ENGS, LoadSave_ENGS, CH_RIFF | CH_LAST},
+	{ 'ENGN', Save_ENGN,     Load_ENGN,     CH_ARRAY          },
+	{ 'ENGS', LoadSave_ENGS, LoadSave_ENGS, CH_RIFF           },
+	{ 'ERNW', Save_ERNW,     Load_ERNW,     CH_ARRAY | CH_LAST},
 };
 
-
-/*
- * returns true if an engine is valid, of the specified type, and buildable by
- * the current player, false otherwise
- *
- * engine = index of the engine to check
- * type   = the type the engine should be of (VEH_xxx)
- */
-bool IsEngineBuildable(uint engine, byte type)
+void InitializeEngines(void)
 {
-	const Engine *e;
-
-	// check if it's an engine that is in the engine array
-	if (!IsEngineIndex(engine)) return false;
-
-	e = GetEngine(engine);
-
-	// check if it's an engine of specified type
-	if (e->type != type) return false;
-
-	// check if it's available
-	if (!HASBIT(e->player_avail, _current_player)) return false;
-
-	return true;
+	/* Clean the engine renew pool and create 1 block in it */
+	CleanPool(&_engine_renew_pool);
+	AddBlockToPool(&_engine_renew_pool);
 }
diff --git a/engine.h b/engine.h
index be8e21aa7..7b32c96a5 100644
--- a/engine.h
+++ b/engine.h
@@ -7,6 +7,7 @@
   */
 
 #include "sprite.h"
+#include "pool.h"
 
 typedef struct RailVehicleInfo {
 	byte image_index;
@@ -102,6 +103,10 @@ enum {
 	NUM_VEHICLE_TYPES = 6
 };
 
+enum {
+	INVALID_ENGINE = 0xFFFF,
+};
+
 void AddTypeToEngines(void);
 void StartupEngines(void);
 
@@ -283,4 +288,80 @@ void UnloadWagonOverrides(void);
 void UnloadCustomEngineSprites(void);
 void UnloadCustomEngineNames(void);
 
+/************************************************************************
+ * Engine Replacement stuff
+ ************************************************************************/
+
+/**
+ * Struct to store engine replacements. DO NOT USE outside of engine.c. Is
+ * placed here so the only exception to this rule, the saveload code, can use
+ * it.
+ */
+struct EngineRenew {
+	uint16 index;
+	EngineID from;
+	EngineID to;
+	struct EngineRenew *next;
+};
+
+typedef struct EngineRenew EngineRenew;
+
+/**
+ * Memory pool for engine renew elements. DO NOT USE outside of engine.c. Is
+ * placed here so the only exception to this rule, the saveload code, can use
+ * it.
+ */
+extern MemoryPool _engine_renew_pool;
+
+/**
+ * DO NOT USE outside of engine.c. Is
+ * placed here so the only exception to this rule, the saveload code, can use
+ * it.
+ */
+static inline EngineRenew *GetEngineRenew(uint16 index)
+{
+	return (EngineRenew*)GetItemFromPool(&_engine_renew_pool, index);
+}
+
+
+/**
+ * A list to group EngineRenew directives together (such as per-player).
+ */
+typedef EngineRenew* EngineRenewList;
+
+/**
+ * Remove all engine replacement settings for the player.
+ * @param  er The renewlist for a given player.
+ * @return The new renewlist for the player.
+ */
+void RemoveAllEngineReplacement(EngineRenewList* erl);
+
+/**
+ * Retrieve the engine replacement in a given renewlist for an original engine type.
+ * @param  erl The renewlist to search in.
+ * @param  engine Engine type to be replaced.
+ * @return The engine type to replace with, or INVALID_ENGINE if no
+ * replacement is in the list.
+ */
+EngineID EngineReplacement(EngineRenewList erl, EngineID engine);
+
+/**
+ * Add an engine replacement to the given renewlist.
+ * @param erl The renewlist to add to.
+ * @param old_engine The original engine type.
+ * @param new_engine The replacement engine type.
+ * @param flags The calling command flags.
+ * @return 0 on success, CMD_ERROR on failure.
+ */
+int32 AddEngineReplacement(EngineRenewList* erl, EngineID old_engine, EngineID new_engine, uint32 flags);
+
+/**
+ * Remove an engine replacement from a given renewlist.
+ * @param erl The renewlist from which to remove the replacement
+ * @param engine The original engine type.
+ * @param flags The calling command flags.
+ * @return 0 on success, CMD_ERROR on failure.
+ */
+int32 RemoveEngineReplacement(EngineRenewList* erl, EngineID engine, uint32 flags);
+
 #endif /* ENGINE_H */
diff --git a/misc.c b/misc.c
index 8abbc5bf8..37256f115 100644
--- a/misc.c
+++ b/misc.c
@@ -89,6 +89,7 @@ void SetDate(uint date)
 void InitializeVehicles(void);
 void InitializeWaypoints(void);
 void InitializeDepot(void);
+void InitializeEngines(void);
 void InitializeOrders(void);
 void InitializeClearLand(void);
 void InitializeRail(void);
@@ -142,6 +143,7 @@ void InitializeGame(int mode, uint size_x, uint size_y)
 		SetDate(starting);
 	}
 
+	InitializeEngines();
 	InitializeVehicles();
 	InitializeWaypoints();
 	InitializeDepot();
diff --git a/openttd.c b/openttd.c
index 58bcb803a..d84e73b18 100644
--- a/openttd.c
+++ b/openttd.c
@@ -1257,7 +1257,7 @@ bool AfterLoadGame(void)
 	 *  of course, we do need to initialize them for older savegames. */
 	if (CheckSavegameVersion(16)) {
 		FOR_ALL_PLAYERS(p) {
-			InitialiseEngineReplacement(p);
+			p->engine_renew_list = NULL;
 			p->engine_renew = false;
 			p->engine_renew_months = -6;
 			p->engine_renew_money = 100000;
diff --git a/player.h b/player.h
index 071dcd2ad..001d17e31 100644
--- a/player.h
+++ b/player.h
@@ -3,6 +3,7 @@
 #ifndef PLAYER_H
 #define PLAYER_H
 
+#include "pool.h"
 #include "aystar.h"
 #include "rail.h"
 #include "engine.h"
@@ -188,7 +189,7 @@ typedef struct Player {
 	int64 yearly_expenses[3][13];
 	PlayerEconomyEntry cur_economy;
 	PlayerEconomyEntry old_economy[24];
-	EngineID engine_replacement[TOTAL_NUM_ENGINES];
+	EngineRenewList engine_renew_list; // Defined later
 	bool engine_renew;
 	bool renew_keep_length;
 	int16 engine_renew_months;
@@ -263,8 +264,48 @@ void LoadFromHighScore(void);
 int8 SaveHighScoreValue(const Player *p);
 int8 SaveHighScoreValueNetwork(void);
 
-void InitialiseEngineReplacement(Player *p);
-EngineID EngineReplacement(const Player *p, EngineID engine);
-bool EngineHasReplacement(const Player *p, EngineID engine);
+/* Engine Replacement Functions */
+
+/**
+ * Remove all engine replacement settings for the given player.
+ * @param p Player.
+ */
+static inline void RemoveAllEngineReplacementForPlayer(Player *p) { RemoveAllEngineReplacement(&p->engine_renew_list); }
+
+/**
+ * Retrieve the engine replacement for the given player and original engine type.
+ * @param p Player.
+ * @param engine Engine type.
+ * @return The engine type to replace with, or INVALID_ENGINE if no
+ * replacement is in the list.
+ */
+static inline EngineID EngineReplacementForPlayer(const Player *p, EngineID engine) { return EngineReplacement(p->engine_renew_list, engine); }
+
+/**
+ * Check if a player has a replacement set up for the given engine.
+ * @param p Player.
+ * @param  engine Engine type to be replaced.
+ * @return true if a replacement was set up, false otherwise.
+ */
+static inline bool EngineHasReplacementForPlayer(const Player *p, EngineID engine) { return EngineReplacementForPlayer(p, engine) != INVALID_ENGINE; }
+
+/**
+ * Add an engine replacement for the player.
+ * @param p Player.
+ * @param old_engine The original engine type.
+ * @param new_engine The replacement engine type.
+ * @param flags The calling command flags.
+ * @return 0 on success, CMD_ERROR on failure.
+ */
+static inline int32 AddEngineReplacementForPlayer(Player *p, EngineID old_engine, EngineID new_engine, uint32 flags) { return AddEngineReplacement(&p->engine_renew_list, old_engine, new_engine, flags); }
+
+/**
+ * Remove an engine replacement for the player.
+ * @param p Player.
+ * @param engine The original engine type.
+ * @param flags The calling command flags.
+ * @return 0 on success, CMD_ERROR on failure.
+ */
+static inline int32 RemoveEngineReplacementForPlayer(Player *p, EngineID engine, uint32 flags) {return RemoveEngineReplacement(&p->engine_renew_list, engine, flags); }
 
 #endif /* PLAYER_H */
diff --git a/players.c b/players.c
index 1b6b99c85..2ea429994 100644
--- a/players.c
+++ b/players.c
@@ -23,6 +23,7 @@
 #include "sound.h"
 #include "network.h"
 #include "variables.h"
+#include "engine.h"
 #include "ai/ai.h"
 
 static const SpriteID cheeks_table[4] = {
@@ -487,7 +488,7 @@ Player *DoStartupNewPlayer(bool is_ai)
 	p->face = Random();
 
 	/* Engine renewal settings */
-	InitialiseEngineReplacement(p);
+	p->engine_renew_list = NULL;
 	p->renew_keep_length = false;
 	p->engine_renew = false;
 	p->engine_renew_months = -6;
@@ -637,10 +638,6 @@ static void DeletePlayerStuff(PlayerID pi)
 	p->president_name_1 = 0;
 }
 
-
-static int32 AddEngineReplacement(Player* p, EngineID old_engine, EngineID new_engine, uint32 flags);
-static int32 RemoveEngineReplacement(Player* p, EngineID engine, uint32 flags);
-
 /** Change engine renewal parameters
  * @param x,y unused
  * @param p1 bits 0-3 command
@@ -734,9 +731,9 @@ int32 CmdReplaceVehicle(int x, int y, uint32 flags, uint32 p1, uint32 p2)
 				if (!HASBIT(GetEngine(new_engine_type)->player_avail, _current_player))
 					return CMD_ERROR;
 
-				cost = AddEngineReplacement(p, old_engine_type, new_engine_type, flags);
+				cost = AddEngineReplacementForPlayer(p, old_engine_type, new_engine_type, flags);
 			} else {
-				cost = RemoveEngineReplacement(p, old_engine_type, flags);
+				cost = RemoveEngineReplacementForPlayer(p, old_engine_type, flags);
 			}
 
 			if (IsLocalPlayer()) InvalidateWindow(WC_REPLACE_VEHICLE, GetEngine(old_engine_type)->type);
@@ -903,6 +900,8 @@ int32 CmdPlayerCtrl(int x, int y, uint32 flags, uint32 p1, uint32 p2)
 			p->money64 = p->player_money = 100000000; // XXX - wtf?
 			p->is_active = false;
 		}
+		RemoveAllEngineReplacementForPlayer(p);
+
 	} break;
 
 	case 3: { /* Merge a company (#1) into another company (#2), elimination company #1 */
@@ -1107,63 +1106,6 @@ void LoadFromHighScore(void)
 	 _patches.ending_date = 2051;
 }
 
-void InitialiseEngineReplacement(Player *p)
-{
-	EngineID engine;
-
-	for (engine = 0; engine < TOTAL_NUM_ENGINES; engine++)
-		p->engine_replacement[engine] = INVALID_ENGINE;
-}
-
-/**
- * Retrieve the engine replacement for the given player and original engine type.
- * @param p Player.
- * @param engine Engine type.
- * @return Assigned replacement engine.
- */
-EngineID EngineReplacement(const Player *p, EngineID engine)
-{
-	return p->engine_replacement[engine];
-}
-
-/**
- * Check if an engine has a replacement set up.
- * @param p Player.
- * @param engine Engine type.
- * @return True if there is a replacement for the original engine type.
- */
-bool EngineHasReplacement(const Player *p, EngineID engine)
-{
-	return EngineReplacement(p, engine) != INVALID_ENGINE;
-}
-
-/**
- * Add an engine replacement for the player.
- * @param p Player.
- * @param old_engine The original engine type.
- * @param new_engine The replacement engine type.
- * @param flags The calling command flags.
- * @return 0 on success, CMD_ERROR on failure.
- */
-static int32 AddEngineReplacement(Player* p, EngineID old_engine, EngineID new_engine, uint32 flags)
-{
-	if (flags & DC_EXEC) p->engine_replacement[old_engine] = new_engine;
-	return 0;
-}
-
-/**
- * Remove an engine replacement for the player.
- * @param p Player.
- * @param engine The original engine type.
- * @param flags The calling command flags.
- * @return 0 on success, CMD_ERROR on failure.
- */
-static int32 RemoveEngineReplacement(Player* p, EngineID engine, uint32 flags)
-{
-	if (flags & DC_EXEC) p->engine_replacement[engine] = INVALID_ENGINE;
-	return 0;
-}
-
 // Save/load of players
 static const SaveLoad _player_desc[] = {
 	SLE_VAR(Player,name_2,					SLE_UINT32),
@@ -1209,7 +1151,8 @@ static const SaveLoad _player_desc[] = {
 	SLE_CONDVAR(Player,is_active,	SLE_UINT8, 4, 255),
 
 	// Engine renewal settings
-	SLE_CONDARR(Player,engine_replacement,  SLE_UINT16, 256, 16, 255),
+	SLE_CONDARR(NullStruct,null,SLE_FILE_U16 | SLE_VAR_NULL, 256, 16, 18),
+	SLE_CONDREF(Player,engine_renew_list, REF_ENGINE_RENEWS, 19, 255),
 	SLE_CONDVAR(Player,engine_renew,         SLE_UINT8,      16, 255),
 	SLE_CONDVAR(Player,engine_renew_months,  SLE_INT16,      16, 255),
 	SLE_CONDVAR(Player,engine_renew_money,  SLE_UINT32,      16, 255),
diff --git a/saveload.c b/saveload.c
index 827abe697..fb141cc91 100644
--- a/saveload.c
+++ b/saveload.c
@@ -29,7 +29,7 @@
 #include <setjmp.h>
 
 enum {
-	SAVEGAME_VERSION = 18,
+	SAVEGAME_VERSION = 19,
 
 };
 
@@ -1051,6 +1051,7 @@ static void UninitWriteZlib(void)
 // these define the chunks
 extern const ChunkHandler _misc_chunk_handlers[];
 extern const ChunkHandler _player_chunk_handlers[];
+extern const ChunkHandler _engine_chunk_handlers[];
 extern const ChunkHandler _veh_chunk_handlers[];
 extern const ChunkHandler _waypoint_chunk_handlers[];
 extern const ChunkHandler _depot_chunk_handlers[];
@@ -1059,7 +1060,6 @@ extern const ChunkHandler _town_chunk_handlers[];
 extern const ChunkHandler _sign_chunk_handlers[];
 extern const ChunkHandler _station_chunk_handlers[];
 extern const ChunkHandler _industry_chunk_handlers[];
-extern const ChunkHandler _engine_chunk_handlers[];
 extern const ChunkHandler _economy_chunk_handlers[];
 extern const ChunkHandler _animated_tile_chunk_handlers[];
 
@@ -1107,6 +1107,7 @@ static uint ReferenceToInt(const void *obj, SLRefType rt)
 		case REF_TOWN:      return ((const     Town*)obj)->index + 1;
 		case REF_ORDER:     return ((const    Order*)obj)->index + 1;
 		case REF_ROADSTOPS: return ((const RoadStop*)obj)->index + 1;
+		case REF_ENGINE_RENEWS: return ((const EngineRenew*)obj)->index + 1;
 		default: NOT_REACHED();
 	}
 
@@ -1162,6 +1163,11 @@ static void *IntToReference(uint index, SLRefType rt)
 				error("RoadStops: failed loading savegame: too many RoadStops");
 			return GetRoadStop(index);
 		}
+		case REF_ENGINE_RENEWS: {
+			if (!AddBlockIfNeeded(&_engine_renew_pool, index))
+				error("EngineRenews: failed loading savegame: too many EngineRenews");
+			return GetEngineRenew(index);
+		}
 
 		case REF_VEHICLE_OLD: {
 			/* Old vehicles were saved differently:
diff --git a/saveload.h b/saveload.h
index 6a3d2e5e4..e5bd04b47 100644
--- a/saveload.h
+++ b/saveload.h
@@ -47,7 +47,8 @@ typedef enum SLRefType {
 	REF_STATION     = 2,
 	REF_TOWN        = 3,
 	REF_VEHICLE_OLD = 4,
-	REF_ROADSTOPS   = 5
+	REF_ROADSTOPS   = 5,
+	REF_ENGINE_RENEWS = 6,
 } SLRefType;
 
 
diff --git a/vehicle.c b/vehicle.c
index 45f7c6ee8..b7fa42aee 100644
--- a/vehicle.c
+++ b/vehicle.c
@@ -1618,7 +1618,7 @@ static int32 ReplaceVehicle(Vehicle **w, byte flags)
 	Vehicle *new_v = NULL;
 	char vehicle_name[32];
 
-	new_engine_type = EngineReplacement(p, old_v->engine_type);
+	new_engine_type = EngineReplacementForPlayer(p, old_v->engine_type);
 	if (new_engine_type == INVALID_ENGINE) new_engine_type = old_v->engine_type;
 
 	cost = DoCommand(old_v->x_pos, old_v->y_pos, new_engine_type, 1, flags, CMD_BUILD_VEH(old_v->type));
@@ -1739,7 +1739,7 @@ static void MaybeReplaceVehicle(Vehicle *v)
 			if (!p->engine_renew ||
 					w->age - w->max_age < (p->engine_renew_months * 30) || // replace if engine is too old
 					w->max_age == 0) { // rail cars got a max age of 0
-				if (!EngineHasReplacement(p, w->engine_type)) // updates to a new model
+				if (!EngineHasReplacementForPlayer(p, w->engine_type)) // updates to a new model
 					continue;
 			}
 
diff --git a/vehicle.h b/vehicle.h
index ea63de569..c00f0b8da 100644
--- a/vehicle.h
+++ b/vehicle.h
@@ -427,7 +427,6 @@ VARDEF uint16 _aircraft_refit_capacity;
 VARDEF byte _cmd_build_rail_veh_score;
 
 #define INVALID_VEHICLE 0xFFFF
-#define INVALID_ENGINE 0xFFFF
 
 /* A lot of code calls for the invalidation of the status bar, which is widget 5.
  * Best is to have a virtual value for it when it needs to change again */
diff --git a/vehicle_gui.c b/vehicle_gui.c
index 43fd33976..14a77130e 100644
--- a/vehicle_gui.c
+++ b/vehicle_gui.c
@@ -422,7 +422,7 @@ static void train_engine_drawing_loop(int *x, int *y, int *pos, int *sel, Engine
 		const RailVehicleInfo *rvi = RailVehInfo(i);
 		const EngineInfo *info = &_engine_info[i];
 
-		if (!EngineHasReplacement(p, i) && _player_num_engines[i] == 0 && show_outdated) continue;
+		if (!EngineHasReplacementForPlayer(p, i) && _player_num_engines[i] == 0 && show_outdated) continue;
 
 		if (rvi->power == 0 && !show_cars)   // disables display of cars (works since they do not have power)
 			continue;
@@ -481,7 +481,7 @@ static void SetupScrollStuffForReplaceWindow(Window *w)
 				const EngineInfo *info = &_engine_info[engine_id];
 
 				if (ENGINE_AVAILABLE && RailVehInfo(engine_id)->power && e->railtype == railtype) {
-					if (_player_num_engines[engine_id] > 0 || EngineHasReplacement(p, engine_id)) {
+					if (_player_num_engines[engine_id] > 0 || EngineHasReplacementForPlayer(p, engine_id)) {
 						if (sel[0] == 0) selected_id[0] = engine_id;
 						count++;
 						sel[0]--;
@@ -502,7 +502,7 @@ static void SetupScrollStuffForReplaceWindow(Window *w)
 			engine_id = ROAD_ENGINES_INDEX;
 
 			do {
-				if (_player_num_engines[engine_id] > 0 || EngineHasReplacement(p, engine_id)) {
+				if (_player_num_engines[engine_id] > 0 || EngineHasReplacementForPlayer(p, engine_id)) {
 					if (sel[0] == 0) selected_id[0] = engine_id;
 					count++;
 					sel[0]--;
@@ -533,7 +533,7 @@ static void SetupScrollStuffForReplaceWindow(Window *w)
 			engine_id = SHIP_ENGINES_INDEX;
 
 			do {
-				if (_player_num_engines[engine_id] > 0 || EngineHasReplacement(p, engine_id)) {
+				if (_player_num_engines[engine_id] > 0 || EngineHasReplacementForPlayer(p, engine_id)) {
 					if (sel[0] == 0) selected_id[0] = engine_id;
 					count++;
 					sel[0]--;
@@ -566,7 +566,7 @@ static void SetupScrollStuffForReplaceWindow(Window *w)
 			engine_id = AIRCRAFT_ENGINES_INDEX;
 
 			do {
-				if (_player_num_engines[engine_id] > 0 || EngineHasReplacement(p, engine_id)) {
+				if (_player_num_engines[engine_id] > 0 || EngineHasReplacementForPlayer(p, engine_id)) {
 					count++;
 					if (sel[0] == 0) selected_id[0] = engine_id;
 					sel[0]--;
@@ -643,7 +643,7 @@ static void DrawEngineArrayInReplaceWindow(Window *w, int x, int y, int x2, int
 				cargo = RoadVehInfo(selected_id[0])->cargo_type;
 
 				do {
-					if (_player_num_engines[engine_id] > 0 || EngineHasReplacement(p, engine_id)) {
+					if (_player_num_engines[engine_id] > 0 || EngineHasReplacementForPlayer(p, engine_id)) {
 						if (IS_INT_INSIDE(--pos, -w->vscroll.cap, 0)) {
 							DrawString(x+59, y+2, GetCustomEngineName(engine_id), sel[0]==0 ? 0xC : 0x10);
 							DrawRoadVehEngine(x+29, y+6, engine_id, _player_num_engines[engine_id] > 0 ? SPRITE_PALETTE(PLAYER_SPRITE_COLOR(_local_player)) : PALETTE_CRASH);
@@ -678,7 +678,7 @@ static void DrawEngineArrayInReplaceWindow(Window *w, int x, int y, int x2, int
 				refittable = ShipVehInfo(selected_id[0])->refittable;
 
 				do {
-					if (_player_num_engines[engine_id] > 0 || EngineHasReplacement(p, engine_id)) {
+					if (_player_num_engines[engine_id] > 0 || EngineHasReplacementForPlayer(p, engine_id)) {
 						if (IS_INT_INSIDE(--pos, -w->vscroll.cap, 0)) {
 							DrawString(x+75, y+7, GetCustomEngineName(engine_id), sel[0]==0 ? 0xC : 0x10);
 							DrawShipEngine(x+35, y+10, engine_id, _player_num_engines[engine_id] > 0 ? SPRITE_PALETTE(PLAYER_SPRITE_COLOR(_local_player)) : PALETTE_CRASH);
@@ -711,7 +711,7 @@ static void DrawEngineArrayInReplaceWindow(Window *w, int x, int y, int x2, int
 				byte subtype = AircraftVehInfo(selected_id[0])->subtype;
 
 				do {
-					if (_player_num_engines[engine_id] > 0 || EngineHasReplacement(p, engine_id)) {
+					if (_player_num_engines[engine_id] > 0 || EngineHasReplacementForPlayer(p, engine_id)) {
 						if (sel[0] == 0) selected_id[0] = engine_id;
 						if (IS_INT_INSIDE(--pos, -w->vscroll.cap, 0)) {
 							DrawString(x+62, y+7, GetCustomEngineName(engine_id), sel[0]==0 ? 0xC : 0x10);
@@ -825,8 +825,8 @@ static void ReplaceVehicleWndProc(Window *w, WindowEvent *e)
 				if (selected_id[0] == INVALID_ENGINE ||
 						selected_id[1] == INVALID_ENGINE ||
 						selected_id[0] == selected_id[1] ||
-						EngineReplacement(p, selected_id[1]) != INVALID_ENGINE ||
-						EngineReplacement(p, selected_id[0]) == selected_id[1]) {
+						EngineReplacementForPlayer(p, selected_id[1]) != INVALID_ENGINE ||
+						EngineReplacementForPlayer(p, selected_id[0]) == selected_id[1]) {
 					SETBIT(w->disabled_state, 4);
 				} else {
 					CLRBIT(w->disabled_state, 4);
@@ -836,7 +836,7 @@ static void ReplaceVehicleWndProc(Window *w, WindowEvent *e)
 				//    The left list (existing vehicle) is empty
 				// or The selected vehicle has no replacement set up
 				if (selected_id[0] == INVALID_ENGINE ||
-						!EngineHasReplacement(p, selected_id[0])) {
+						!EngineHasReplacementForPlayer(p, selected_id[0])) {
 					SETBIT(w->disabled_state, 6);
 				} else {
 					CLRBIT(w->disabled_state, 6);
@@ -854,10 +854,10 @@ static void ReplaceVehicleWndProc(Window *w, WindowEvent *e)
 
 				// sets up the string for the vehicle that is being replaced to
 				if (selected_id[0] != INVALID_ENGINE) {
-					if (!EngineHasReplacement(p, selected_id[0])) {
+					if (!EngineHasReplacementForPlayer(p, selected_id[0])) {
 						SetDParam(0, STR_NOT_REPLACING);
 					} else {
-						SetDParam(0, GetCustomEngineName(EngineReplacement(p, selected_id[0])));
+						SetDParam(0, GetCustomEngineName(EngineReplacementForPlayer(p, selected_id[0])));
 					}
 				} else {
 					SetDParam(0, STR_NOT_REPLACING_VEHICLE_SELECTED);