Change: prefix SL_ARR with the length of the array

This means that during loading we can validate that what is saved
is also that what is expected. Additionally, this makes all list
types similar to how they are stored on disk:
First a gamma to indicate length, followed by the data.
The size still depends on the type.

8 files changed, 112 insertions, 64 deletions

diff --git a/src/saveload/animated_tile_sl.cpp b/src/saveload/animated_tile_sl.cpp
index 2b3842104..89eb881b1 100644
--- a/src/saveload/animated_tile_sl.cpp
+++ b/src/saveload/animated_tile_sl.cpp
@@ -24,7 +24,7 @@ extern std::vector<TileIndex> _animated_tiles;
 static void Save_ANIT()
 {
 	SlSetLength(_animated_tiles.size() * sizeof(_animated_tiles.front()));
-	SlArray(_animated_tiles.data(), _animated_tiles.size(), SLE_UINT32);
+	SlCopy(_animated_tiles.data(), _animated_tiles.size(), SLE_UINT32);
 }
 
 /**
@@ -36,7 +36,7 @@ static void Load_ANIT()
 	if (IsSavegameVersionBefore(SLV_80)) {
 		/* In pre version 6, we has 16bit per tile, now we have 32bit per tile, convert it ;) */
 		TileIndex anim_list[256];
-		SlArray(anim_list, 256, IsSavegameVersionBefore(SLV_6) ? (SLE_FILE_U16 | SLE_VAR_U32) : SLE_UINT32);
+		SlCopy(anim_list, 256, IsSavegameVersionBefore(SLV_6) ? (SLE_FILE_U16 | SLE_VAR_U32) : SLE_UINT32);
 
 		for (int i = 0; i < 256; i++) {
 			if (anim_list[i] == 0) break;
@@ -48,7 +48,7 @@ static void Load_ANIT()
 	uint count = (uint)SlGetFieldLength() / sizeof(_animated_tiles.front());
 	_animated_tiles.clear();
 	_animated_tiles.resize(_animated_tiles.size() + count);
-	SlArray(_animated_tiles.data(), count, SLE_UINT32);
+	SlCopy(_animated_tiles.data(), count, SLE_UINT32);
 }
 
 /**
diff --git a/src/saveload/economy_sl.cpp b/src/saveload/economy_sl.cpp
index b51151c14..82e3014ad 100644
--- a/src/saveload/economy_sl.cpp
+++ b/src/saveload/economy_sl.cpp
@@ -20,8 +20,8 @@ static void Load_PRIC()
 {
 	/* Old games store 49 base prices, very old games store them as int32 */
 	int vt = IsSavegameVersionBefore(SLV_65) ? SLE_FILE_I32 : SLE_FILE_I64;
-	SlArray(nullptr, 49, vt | SLE_VAR_NULL);
-	SlArray(nullptr, 49, SLE_FILE_U16 | SLE_VAR_NULL);
+	SlCopy(nullptr, 49, vt | SLE_VAR_NULL);
+	SlCopy(nullptr, 49, SLE_FILE_U16 | SLE_VAR_NULL);
 }
 
 /** Cargo payment rates in pre 126 savegames */
@@ -29,8 +29,8 @@ static void Load_CAPR()
 {
 	uint num_cargo = IsSavegameVersionBefore(SLV_55) ? 12 : IsSavegameVersionBefore(SLV_EXTEND_CARGOTYPES) ? 32 : NUM_CARGO;
 	int vt = IsSavegameVersionBefore(SLV_65) ? SLE_FILE_I32 : SLE_FILE_I64;
-	SlArray(nullptr, num_cargo, vt | SLE_VAR_NULL);
-	SlArray(nullptr, num_cargo, SLE_FILE_U16 | SLE_VAR_NULL);
+	SlCopy(nullptr, num_cargo, vt | SLE_VAR_NULL);
+	SlCopy(nullptr, num_cargo, SLE_FILE_U16 | SLE_VAR_NULL);
 }
 
 static const SaveLoad _economy_desc[] = {
diff --git a/src/saveload/engine_sl.cpp b/src/saveload/engine_sl.cpp
index 430ae29d1..336c93282 100644
--- a/src/saveload/engine_sl.cpp
+++ b/src/saveload/engine_sl.cpp
@@ -156,7 +156,7 @@ static void Load_ENGS()
 	 * was always 256 entries. */
 	StringID names[256];
 
-	SlArray(names, lengthof(names), SLE_STRINGID);
+	SlCopy(names, lengthof(names), SLE_STRINGID);
 
 	/* Copy each string into the temporary engine array. */
 	for (EngineID engine = 0; engine < lengthof(names); engine++) {
diff --git a/src/saveload/map_sl.cpp b/src/saveload/map_sl.cpp
index d13900fc6..5924f4440 100644
--- a/src/saveload/map_sl.cpp
+++ b/src/saveload/map_sl.cpp
@@ -53,7 +53,7 @@ static void Load_MAPT()
 	TileIndex size = MapSize();
 
 	for (TileIndex i = 0; i != size;) {
-		SlArray(buf.data(), MAP_SL_BUF_SIZE, SLE_UINT8);
+		SlCopy(buf.data(), MAP_SL_BUF_SIZE, SLE_UINT8);
 		for (uint j = 0; j != MAP_SL_BUF_SIZE; j++) _m[i++].type = buf[j];
 	}
 }
@@ -66,7 +66,7 @@ static void Save_MAPT()
 	SlSetLength(size);
 	for (TileIndex i = 0; i != size;) {
 		for (uint j = 0; j != MAP_SL_BUF_SIZE; j++) buf[j] = _m[i++].type;
-		SlArray(buf.data(), MAP_SL_BUF_SIZE, SLE_UINT8);
+		SlCopy(buf.data(), MAP_SL_BUF_SIZE, SLE_UINT8);
 	}
 }
 
@@ -76,7 +76,7 @@ static void Load_MAPH()
 	TileIndex size = MapSize();
 
 	for (TileIndex i = 0; i != size;) {
-		SlArray(buf.data(), MAP_SL_BUF_SIZE, SLE_UINT8);
+		SlCopy(buf.data(), MAP_SL_BUF_SIZE, SLE_UINT8);
 		for (uint j = 0; j != MAP_SL_BUF_SIZE; j++) _m[i++].height = buf[j];
 	}
 }
@@ -89,7 +89,7 @@ static void Save_MAPH()
 	SlSetLength(size);
 	for (TileIndex i = 0; i != size;) {
 		for (uint j = 0; j != MAP_SL_BUF_SIZE; j++) buf[j] = _m[i++].height;
-		SlArray(buf.data(), MAP_SL_BUF_SIZE, SLE_UINT8);
+		SlCopy(buf.data(), MAP_SL_BUF_SIZE, SLE_UINT8);
 	}
 }
 
@@ -99,7 +99,7 @@ static void Load_MAP1()
 	TileIndex size = MapSize();
 
 	for (TileIndex i = 0; i != size;) {
-		SlArray(buf.data(), MAP_SL_BUF_SIZE, SLE_UINT8);
+		SlCopy(buf.data(), MAP_SL_BUF_SIZE, SLE_UINT8);
 		for (uint j = 0; j != MAP_SL_BUF_SIZE; j++) _m[i++].m1 = buf[j];
 	}
 }
@@ -112,7 +112,7 @@ static void Save_MAP1()
 	SlSetLength(size);
 	for (TileIndex i = 0; i != size;) {
 		for (uint j = 0; j != MAP_SL_BUF_SIZE; j++) buf[j] = _m[i++].m1;
-		SlArray(buf.data(), MAP_SL_BUF_SIZE, SLE_UINT8);
+		SlCopy(buf.data(), MAP_SL_BUF_SIZE, SLE_UINT8);
 	}
 }
 
@@ -122,7 +122,7 @@ static void Load_MAP2()
 	TileIndex size = MapSize();
 
 	for (TileIndex i = 0; i != size;) {
-		SlArray(buf.data(), MAP_SL_BUF_SIZE,
+		SlCopy(buf.data(), MAP_SL_BUF_SIZE,
 			/* In those versions the m2 was 8 bits */
 			IsSavegameVersionBefore(SLV_5) ? SLE_FILE_U8 | SLE_VAR_U16 : SLE_UINT16
 		);
@@ -138,7 +138,7 @@ static void Save_MAP2()
 	SlSetLength(size * sizeof(uint16));
 	for (TileIndex i = 0; i != size;) {
 		for (uint j = 0; j != MAP_SL_BUF_SIZE; j++) buf[j] = _m[i++].m2;
-		SlArray(buf.data(), MAP_SL_BUF_SIZE, SLE_UINT16);
+		SlCopy(buf.data(), MAP_SL_BUF_SIZE, SLE_UINT16);
 	}
 }
 
@@ -148,7 +148,7 @@ static void Load_MAP3()
 	TileIndex size = MapSize();
 
 	for (TileIndex i = 0; i != size;) {
-		SlArray(buf.data(), MAP_SL_BUF_SIZE, SLE_UINT8);
+		SlCopy(buf.data(), MAP_SL_BUF_SIZE, SLE_UINT8);
 		for (uint j = 0; j != MAP_SL_BUF_SIZE; j++) _m[i++].m3 = buf[j];
 	}
 }
@@ -161,7 +161,7 @@ static void Save_MAP3()
 	SlSetLength(size);
 	for (TileIndex i = 0; i != size;) {
 		for (uint j = 0; j != MAP_SL_BUF_SIZE; j++) buf[j] = _m[i++].m3;
-		SlArray(buf.data(), MAP_SL_BUF_SIZE, SLE_UINT8);
+		SlCopy(buf.data(), MAP_SL_BUF_SIZE, SLE_UINT8);
 	}
 }
 
@@ -171,7 +171,7 @@ static void Load_MAP4()
 	TileIndex size = MapSize();
 
 	for (TileIndex i = 0; i != size;) {
-		SlArray(buf.data(), MAP_SL_BUF_SIZE, SLE_UINT8);
+		SlCopy(buf.data(), MAP_SL_BUF_SIZE, SLE_UINT8);
 		for (uint j = 0; j != MAP_SL_BUF_SIZE; j++) _m[i++].m4 = buf[j];
 	}
 }
@@ -184,7 +184,7 @@ static void Save_MAP4()
 	SlSetLength(size);
 	for (TileIndex i = 0; i != size;) {
 		for (uint j = 0; j != MAP_SL_BUF_SIZE; j++) buf[j] = _m[i++].m4;
-		SlArray(buf.data(), MAP_SL_BUF_SIZE, SLE_UINT8);
+		SlCopy(buf.data(), MAP_SL_BUF_SIZE, SLE_UINT8);
 	}
 }
 
@@ -194,7 +194,7 @@ static void Load_MAP5()
 	TileIndex size = MapSize();
 
 	for (TileIndex i = 0; i != size;) {
-		SlArray(buf.data(), MAP_SL_BUF_SIZE, SLE_UINT8);
+		SlCopy(buf.data(), MAP_SL_BUF_SIZE, SLE_UINT8);
 		for (uint j = 0; j != MAP_SL_BUF_SIZE; j++) _m[i++].m5 = buf[j];
 	}
 }
@@ -207,7 +207,7 @@ static void Save_MAP5()
 	SlSetLength(size);
 	for (TileIndex i = 0; i != size;) {
 		for (uint j = 0; j != MAP_SL_BUF_SIZE; j++) buf[j] = _m[i++].m5;
-		SlArray(buf.data(), MAP_SL_BUF_SIZE, SLE_UINT8);
+		SlCopy(buf.data(), MAP_SL_BUF_SIZE, SLE_UINT8);
 	}
 }
 
@@ -219,7 +219,7 @@ static void Load_MAP6()
 	if (IsSavegameVersionBefore(SLV_42)) {
 		for (TileIndex i = 0; i != size;) {
 			/* 1024, otherwise we overflow on 64x64 maps! */
-			SlArray(buf.data(), 1024, SLE_UINT8);
+			SlCopy(buf.data(), 1024, SLE_UINT8);
 			for (uint j = 0; j != 1024; j++) {
 				_me[i++].m6 = GB(buf[j], 0, 2);
 				_me[i++].m6 = GB(buf[j], 2, 2);
@@ -229,7 +229,7 @@ static void Load_MAP6()
 		}
 	} else {
 		for (TileIndex i = 0; i != size;) {
-			SlArray(buf.data(), MAP_SL_BUF_SIZE, SLE_UINT8);
+			SlCopy(buf.data(), MAP_SL_BUF_SIZE, SLE_UINT8);
 			for (uint j = 0; j != MAP_SL_BUF_SIZE; j++) _me[i++].m6 = buf[j];
 		}
 	}
@@ -243,7 +243,7 @@ static void Save_MAP6()
 	SlSetLength(size);
 	for (TileIndex i = 0; i != size;) {
 		for (uint j = 0; j != MAP_SL_BUF_SIZE; j++) buf[j] = _me[i++].m6;
-		SlArray(buf.data(), MAP_SL_BUF_SIZE, SLE_UINT8);
+		SlCopy(buf.data(), MAP_SL_BUF_SIZE, SLE_UINT8);
 	}
 }
 
@@ -253,7 +253,7 @@ static void Load_MAP7()
 	TileIndex size = MapSize();
 
 	for (TileIndex i = 0; i != size;) {
-		SlArray(buf.data(), MAP_SL_BUF_SIZE, SLE_UINT8);
+		SlCopy(buf.data(), MAP_SL_BUF_SIZE, SLE_UINT8);
 		for (uint j = 0; j != MAP_SL_BUF_SIZE; j++) _me[i++].m7 = buf[j];
 	}
 }
@@ -266,7 +266,7 @@ static void Save_MAP7()
 	SlSetLength(size);
 	for (TileIndex i = 0; i != size;) {
 		for (uint j = 0; j != MAP_SL_BUF_SIZE; j++) buf[j] = _me[i++].m7;
-		SlArray(buf.data(), MAP_SL_BUF_SIZE, SLE_UINT8);
+		SlCopy(buf.data(), MAP_SL_BUF_SIZE, SLE_UINT8);
 	}
 }
 
@@ -276,7 +276,7 @@ static void Load_MAP8()
 	TileIndex size = MapSize();
 
 	for (TileIndex i = 0; i != size;) {
-		SlArray(buf.data(), MAP_SL_BUF_SIZE, SLE_UINT16);
+		SlCopy(buf.data(), MAP_SL_BUF_SIZE, SLE_UINT16);
 		for (uint j = 0; j != MAP_SL_BUF_SIZE; j++) _me[i++].m8 = buf[j];
 	}
 }
@@ -289,7 +289,7 @@ static void Save_MAP8()
 	SlSetLength(size * sizeof(uint16));
 	for (TileIndex i = 0; i != size;) {
 		for (uint j = 0; j != MAP_SL_BUF_SIZE; j++) buf[j] = _me[i++].m8;
-		SlArray(buf.data(), MAP_SL_BUF_SIZE, SLE_UINT16);
+		SlCopy(buf.data(), MAP_SL_BUF_SIZE, SLE_UINT16);
 	}
 }
 
diff --git a/src/saveload/order_sl.cpp b/src/saveload/order_sl.cpp
index 523a8b804..81e485606 100644
--- a/src/saveload/order_sl.cpp
+++ b/src/saveload/order_sl.cpp
@@ -141,7 +141,7 @@ static void Load_ORDR()
 			len /= sizeof(uint16);
 			uint16 *orders = MallocT<uint16>(len + 1);
 
-			SlArray(orders, len, SLE_UINT16);
+			SlCopy(orders, len, SLE_UINT16);
 
 			for (size_t i = 0; i < len; ++i) {
 				Order *o = new (i) Order();
@@ -153,7 +153,7 @@ static void Load_ORDR()
 			len /= sizeof(uint32);
 			uint32 *orders = MallocT<uint32>(len + 1);
 
-			SlArray(orders, len, SLE_UINT32);
+			SlCopy(orders, len, SLE_UINT32);
 
 			for (size_t i = 0; i < len; ++i) {
 				new (i) Order(orders[i]);
diff --git a/src/saveload/saveload.cpp b/src/saveload/saveload.cpp
index d4ca1b308..04002fd3f 100644
--- a/src/saveload/saveload.cpp
+++ b/src/saveload/saveload.cpp
@@ -1043,51 +1043,34 @@ static void SlStdString(void *ptr, VarType conv)
 }
 
 /**
- * Return the size in bytes of a certain type of atomic array
- * @param length The length of the array counted in elements
- * @param conv VarType type of the variable that is used in calculating the size
+ * Internal function to save/Load a list of SL_VARs.
+ * SlCopy() and SlArray() are very similar, with the exception of the header.
+ * This function represents the common part.
+ * @param object The object being manipulated.
+ * @param length The length of the object in elements
+ * @param conv VarType type of the items.
  */
-static inline size_t SlCalcArrayLen(size_t length, VarType conv)
+static void SlCopyInternal(void *object, size_t length, VarType conv)
 {
-	return SlCalcConvFileLen(conv) * length;
-}
-
-/**
- * Save/Load an array.
- * @param array The array being manipulated
- * @param length The length of the array in elements
- * @param conv VarType type of the atomic array (int, byte, uint64, etc.)
- */
-void SlArray(void *array, size_t length, VarType conv)
-{
-	if (_sl.action == SLA_PTRS || _sl.action == SLA_NULL) return;
-
-	/* Automatically calculate the length? */
-	if (_sl.need_length != NL_NONE) {
-		SlSetLength(SlCalcArrayLen(length, conv));
-		/* Determine length only? */
-		if (_sl.need_length == NL_CALCLENGTH) return;
-	}
-
 	if (GetVarMemType(conv) == SLE_VAR_NULL) {
 		assert(_sl.action != SLA_SAVE); // Use SL_NULL if you want to write null-bytes
-		SlSkipBytes(SlCalcArrayLen(length, conv));
+		SlSkipBytes(length * SlCalcConvFileLen(conv));
 		return;
 	}
 
 	/* NOTICE - handle some buggy stuff, in really old versions everything was saved
-	 * as a byte-type. So detect this, and adjust array size accordingly */
+	 * as a byte-type. So detect this, and adjust object size accordingly */
 	if (_sl.action != SLA_SAVE && _sl_version == 0) {
-		/* all arrays except difficulty settings */
+		/* all objects except difficulty settings */
 		if (conv == SLE_INT16 || conv == SLE_UINT16 || conv == SLE_STRINGID ||
 				conv == SLE_INT32 || conv == SLE_UINT32) {
-			SlCopyBytes(array, length * SlCalcConvFileLen(conv));
+			SlCopyBytes(object, length * SlCalcConvFileLen(conv));
 			return;
 		}
 		/* used for conversion of Money 32bit->64bit */
 		if (conv == (SLE_FILE_I32 | SLE_VAR_I64)) {
 			for (uint i = 0; i < length; i++) {
-				((int64*)array)[i] = (int32)BSWAP32(SlReadUint32());
+				((int64*)object)[i] = (int32)BSWAP32(SlReadUint32());
 			}
 			return;
 		}
@@ -1096,9 +1079,9 @@ void SlArray(void *array, size_t length, VarType conv)
 	/* If the size of elements is 1 byte both in file and memory, no special
 	 * conversion is needed, use specialized copy-copy function to speed up things */
 	if (conv == SLE_INT8 || conv == SLE_UINT8) {
-		SlCopyBytes(array, length);
+		SlCopyBytes(object, length);
 	} else {
-		byte *a = (byte*)array;
+		byte *a = (byte*)object;
 		byte mem_size = SlCalcConvMemLen(conv);
 
 		for (; length != 0; length --) {
@@ -1108,6 +1091,71 @@ void SlArray(void *array, size_t length, VarType conv)
 	}
 }
 
+/**
+ * Copy a list of SL_VARs to/from a savegame.
+ * These entries are copied as-is, and you as caller have to make sure things
+ * like length-fields are calculated correctly.
+ * @param object The object being manipulated.
+ * @param length The length of the object in elements
+ * @param conv VarType type of the items.
+ */
+void SlCopy(void *object, size_t length, VarType conv)
+{
+	if (_sl.action == SLA_PTRS || _sl.action == SLA_NULL) return;
+
+	/* Automatically calculate the length? */
+	if (_sl.need_length != NL_NONE) {
+		SlSetLength(length * SlCalcConvFileLen(conv));
+		/* Determine length only? */
+		if (_sl.need_length == NL_CALCLENGTH) return;
+	}
+
+	SlCopyInternal(object, length, conv);
+}
+
+/**
+ * Return the size in bytes of a certain type of atomic array
+ * @param length The length of the array counted in elements
+ * @param conv VarType type of the variable that is used in calculating the size
+ */
+static inline size_t SlCalcArrayLen(size_t length, VarType conv)
+{
+	return SlCalcConvFileLen(conv) * length + SlGetArrayLength(length);
+}
+
+/**
+ * Save/Load the length of the array followed by the array of SL_VAR elements.
+ * @param array The array being manipulated
+ * @param length The length of the array in elements
+ * @param conv VarType type of the atomic array (int, byte, uint64, etc.)
+ */
+static void SlArray(void *array, size_t length, VarType conv)
+{
+	switch (_sl.action) {
+		case SLA_SAVE:
+			SlWriteArrayLength(length);
+			SlCopyInternal(array, length, conv);
+			return;
+
+		case SLA_LOAD_CHECK:
+		case SLA_LOAD: {
+			if (!IsSavegameVersionBefore(SLV_SAVELOAD_LIST_LENGTH)) {
+				size_t sv_length = SlReadArrayLength();
+				if (sv_length != length) SlErrorCorrupt("Fixed-length array is of wrong length");
+			}
+
+			SlCopyInternal(array, length, conv);
+			return;
+		}
+
+		case SLA_PTRS:
+		case SLA_NULL:
+			return;
+
+		default:
+			NOT_REACHED();
+	}
+}
 
 /**
  * Pointers cannot be saved to a savegame, so this functions gets
diff --git a/src/saveload/saveload.h b/src/saveload/saveload.h
index c63740ae0..7ed76ff2d 100644
--- a/src/saveload/saveload.h
+++ b/src/saveload/saveload.h
@@ -1008,7 +1008,7 @@ byte SlReadByte();
 void SlWriteByte(byte b);
 
 void SlGlobList(const SaveLoadTable &slt);
-void SlArray(void *array, size_t length, VarType conv);
+void SlCopy(void *object, size_t length, VarType conv);
 void SlObject(void *object, const SaveLoadTable &slt);
 void NORETURN SlError(StringID string, const char *extra_msg = nullptr);
 void NORETURN SlErrorCorrupt(const char *msg);
diff --git a/src/saveload/strings_sl.cpp b/src/saveload/strings_sl.cpp
index 52f70b8d5..c4f56ed43 100644
--- a/src/saveload/strings_sl.cpp
+++ b/src/saveload/strings_sl.cpp
@@ -124,7 +124,7 @@ static void Load_NAME()
 		if (index >= NUM_OLD_STRINGS) SlErrorCorrupt("Invalid old name index");
 		if (SlGetFieldLength() > (uint)LEN_OLD_STRINGS) SlErrorCorrupt("Invalid old name length");
 
-		SlArray(&_old_name_array[LEN_OLD_STRINGS * index], SlGetFieldLength(), SLE_UINT8);
+		SlCopy(&_old_name_array[LEN_OLD_STRINGS * index], SlGetFieldLength(), SLE_UINT8);
 		/* Make sure the old name is null terminated */
 		_old_name_array[LEN_OLD_STRINGS * index + LEN_OLD_STRINGS - 1] = '\0';
 	}