Fix save serialization

scripts/loaders/save_loader.gd

@@ -47,7 +47,27 @@ func get_struct(buffer: StreamPeer, struct_name: String) -> Dictionary:
 		return {}
 	return struct_types[struct_name].get_value(buffer, [0, 0])
 
-func get_save_slot(sram: File, slot_id: int):
+func put_struct(buffer: StreamPeer, struct_name: String, data: Dictionary):
+	if not (struct_name in struct_types):
+		print_debug('Attempted to put undeclared struct: "%s"' % struct_name)
+		return
+	struct_types[struct_name].put_value(buffer, data, [0, 0])
+
+func deserialize_save_slot(bytes: PoolByteArray) -> Dictionary:
+	var buffer = StreamPeerBuffer.new()
+	buffer.data_array = bytes
+	return struct_types['Save_slot'].get_value(buffer, [0, 0])
+
+func serialize_save_slot(data: Dictionary) -> PoolByteArray:
+	var buffer = StreamPeerBuffer.new()
+	struct_types['Save_slot'].put_value(buffer, data, [0, 0])
+	var padding := PoolByteArray()
+	padding.resize(0x100)
+	padding.fill(0)
+	buffer.put_data(padding)
+	return buffer.data_array
+
+func get_save_slot(sram: File, slot_id: int) -> StreamPeerBuffer:
 	var buffer := StreamPeerBuffer.new()
 	sram.seek(0x700 * slot_id)
 	buffer.set_data_array(sram.get_buffer(0x700))

scripts/struct.gd

@@ -78,7 +78,7 @@ class UBits extends StructType:
 		return value
 
 	func put_value(buffer: StreamPeer, value, leftover_bits: Array):
-		leftover_bits[1] |= value << bits
+		leftover_bits[1] |= value << leftover_bits[0]
 		leftover_bits[0] += bits
 		while leftover_bits[0] >= 8:
 			buffer.put_8(leftover_bits[1] & 0xFF)

test/unit_tests.gd

@@ -2,6 +2,15 @@ extends Control
 
 var dir_user := Directory.new()
 const P_TESTDATA := 'user://test_data/'
+# Shared state between tests
+var save_slot_buffers = []
+var save_slot_dicts = []
+
+func test(label, input):
+	if input:
+		print('SUCCESS: ' + label)
+	else:
+		print('FAILURE: ' + label)
 
 func load_snes_savefile(filename: String = 'res://test.srm'):
 	var save_file := File.new()
@@ -11,17 +20,14 @@ func load_snes_savefile(filename: String = 'res://test.srm'):
 		var error:
 			print_debug('Failed to open test.srm for reading: %d' % error)
 			return
-	var save_slots = []
-	var save_slot_dicts = []
 	for i in 4:
-		save_slots.append(SaveLoader.get_save_slot(save_file, i))
-		save_slot_dicts.append(SaveLoader.get_struct(save_slots[i], 'Save_slot'))
+		self.save_slot_buffers.append(SaveLoader.get_save_slot(save_file, i))
+		self.save_slot_dicts.append(SaveLoader.deserialize_save_slot(self.save_slot_buffers[i].data_array))
 	print('Loaded test save file')
-	return save_slot_dicts
 
 func generate_known_good_results():
-	var save_slot_dicts = load_snes_savefile()
-	if not save_slot_dicts:
+	load_snes_savefile()
+	if not self.save_slot_dicts:
 		return
 	match dir_user.make_dir_recursive(P_TESTDATA):
 		OK:
@@ -30,7 +36,7 @@ func generate_known_good_results():
 			print_debug('Failed to create "%s" with error code %d' % [P_TESTDATA, error])
 			return
 	var filename := P_TESTDATA + 'test.srm.json'
-	match Common.save_json(filename, save_slot_dicts):
+	match Common.save_json(filename, self.save_slot_dicts):
 		OK:
 			pass
 		var error:
@@ -38,8 +44,8 @@ func generate_known_good_results():
 			return
 
 func test_save_loading() -> bool:
-	var save_slot_dicts = load_snes_savefile()
-	if not save_slot_dicts:
+	load_snes_savefile()
+	if not self.save_slot_dicts:
 		print_debug('Failed to load test savefile')
 		return false
 	var filename := P_TESTDATA + 'test.srm.json'
@@ -47,7 +53,7 @@ func test_save_loading() -> bool:
 	match typeof(known_good):
 		TYPE_ARRAY:
 			print_debug('Comparing known savefile results')
-			return Common.are_arrays_equal(save_slot_dicts, known_good)
+			return Common.are_arrays_equal(self.save_slot_dicts, known_good)
 		TYPE_DICTIONARY:
 			print_debug('Known savefile results "%s" is a dict instead of an array. Did we change formats?' % filename)
 			return false
@@ -55,6 +61,24 @@ func test_save_loading() -> bool:
 			print_debug('Failed to load known savefile results "%s"' % filename)
 			return false
 
+func test_save_serialization() -> bool:
+	if not self.save_slot_dicts:
+		print_debug('test savefile not loaded')
+		return false
+	for i in 4:
+		var bytes = SaveLoader.serialize_save_slot(self.save_slot_dicts[i])
+		if bytes != self.save_slot_buffers[i].data_array:
+			print_debug('Slot %d failed to serialize correctly, rescanning' % i)
+			for j in 0x700:
+				var b1: int = bytes[j]
+				var b2: int = self.save_slot_buffers[i].data_array[j]
+				if b1 != b2:
+					print_debug('Mismatch occurs at byte %d: %d vs %d' % [j, b1, b2])
+			return false
+	return true
+
+
+
 
 # Called when the node enters the scene tree for the first time.
 func _ready() -> void:
@@ -64,5 +88,6 @@ func _ready() -> void:
 		var error:
 			print_debug('Failed to open user directory')
 	# generate_known_good_results()  # Uncomment this to get your sample on first run
-	print(test_save_loading())
+	test('SNES save file loaded to array of dictionaries', test_save_loading())
+	test('SNES save file slots serialized from dictionaries', test_save_serialization())
 	get_tree().quit()