Help with ZIPReader and PackedByteArray

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1

Godot Version

Godot 4.4.1

Question

Hi,
I’m messing around with ZIPPacker and ZIPReader classes, and they use PackedByteArray for their file data. I don’t understand how to convert the data to and from PackedByteArray form.

The example in the documentation looks very easy:

writer.write_file("Hello World".to_utf8_buffer())

So it makes a string and converts it to utf8. Cool, I can convert my vector data data to string (JSON.stringify) and then to utf8. It works but feels stupid.

Then when loading it:

reader.read_file("somefile").get_string_from_utf8()

I can get the bytes and convert that to string and parse vector data from that… Soo many conversions.

What’s the correct way? My data is just an array of vectors.

2

Did this help you ?

Zip test 
extends Node2D

var ZipFileName = "user://archive.zip"

# Called when the node enters the scene tree for the first time.
func _ready():
	var vectorlist = [Vector2(1,2), Vector2(3,4), Vector2(5,6), Vector2(8,9)]
	
	var packed = PackedByteArray(PackedVector2Array(vectorlist).to_byte_array());
	
	write_zip_file("vectors.data", packed)
	var unpacked = read_zip_file("vectors.data")
	
	var newvectorlist = bytes_to_packed_vector2_array(unpacked)
		
	prints("Expected :", vectorlist)
	prints("Get      :", newvectorlist)

func bytes_to_packed_vector4_array(bytes: PackedByteArray) -> PackedVector4Array:
	if bytes.size() % 16 != 0:
		return []
	var result: PackedVector4Array = []
	var count: int = bytes.size() / 16
	result.resize(count)
	for i in count:
		result[i] = Vector4(bytes.decode_float(i * 16), bytes.decode_float(i * 16 + 4), bytes.decode_float(i * 16 + 8), bytes.decode_float(i * 16 + 12))
	return result

func bytes_to_packed_vector3_array(bytes: PackedByteArray) -> PackedVector3Array:
	if bytes.size() % 12 != 0:
		return []
	var result: PackedVector3Array = []
	var count: int = bytes.size() / 12
	result.resize(count)
	for i in count:
		result[i] = Vector3(bytes.decode_float(i * 12), bytes.decode_float(i * 12 + 4), bytes.decode_float(i * 12 + 8))
	return result

func bytes_to_packed_vector2_array(bytes: PackedByteArray) -> PackedVector2Array:
	if bytes.size() % 8 != 0:
		return []
	var result: PackedVector2Array = []
	var count: int = bytes.size() / 8
	result.resize(count)
	for i in count:
		result[i] = Vector2(bytes.decode_float(i * 8), bytes.decode_float(i * 8 + 4))
	return result

# You can take exemple here to load a regular Array
func bytes_to_vector2_array(bytes: PackedByteArray) -> Array[Vector2]:
	if bytes.size() % 8 != 0:
		return []
	var result: Array[Vector2] = []
	var count: int = bytes.size() / 8
	result.resize(count)
	for i in count:
		result[i] = Vector2(bytes.decode_float(i * 8), bytes.decode_float(i * 8 + 4))
	return result

func write_zip_file(file_name : String, packed : PackedByteArray) -> Error:
	var writer = ZIPPacker.new()
	var err = writer.open(ZipFileName)
	if err != OK:
		prints("error", err)
		return err
	writer.start_file(file_name)
	writer.write_file(packed)
	writer.close_file()
	# close zipfile
	writer.close()
	return OK

func read_zip_file(file_name : String)-> PackedByteArray:
	var reader = ZIPReader.new()
	var err = reader.open(ZipFileName)
	if err != OK:
		prints("error", err)
		return PackedByteArray()
	var res = reader.read_file(file_name)
	reader.close()
	return res
3

Yes! Thanks you very much :slight_smile:

But I do think they should just make it work similar to FileAccess. Now it’s pretty much up to the user to replicate those functions.