Gdunzip is a zip file browser/decompressor written entirely in a single GDScript file. You can use this in games you're building with the Godot game engine. This script is meant for modest zip decompressing purposes, since the inflate algorithm it contains isn't super fast and gdunzip doesn't do CRC checks of the uncompressed files. However, gdunzip works fine if you only need to decompress small files, or when your zip files contain precompressed files like png's.
In order to create gdunzip, I have made a GDScript port of Jørgen Ibsen's excellent tiny inflate library: tinf for decompressing the deflate streams. Since the original was written in C and used some nifty pointer arithmetic, I had to make some minor changes here and there to be able to translate it. However, I tried to stay as close to the original code as possible.
The zip file format parsing is all written from scratch and performs pretty well.
I'm working on a little sideproject in Godot: a memorize app. In this app I will allow the user to import an ODS-file: the spreadsheet file format used by LibreOffice and OpenOffice. ODS-files are actually zip files, containing a bunch of xml files and some other assets. I couldn't find a ready-made ODS library for Godot, so I set out creating one. It would have been faster to just use GDNative and hand all the work to a C++ library, but since this is a hobby project and I haven't got much GDScript experience, I thought it would be fun to create it myself. The first step was of course to get an unzipper up and running. I found out that Godot's PoolByteArray has a "decompress" function that supports deflate streams, however these were all in the Zlib format, so you can't use it with regular zip files (zlib uses an Adler-32 checksum to verify decompressed data, but zip files only contain a CRC-32 checksum).
A more sensible person might have just stepped back and pulled some pre-existing C++ library off the shelf, however I thought it would be fun to dive in and gdunzip is the result :-).
# Instance the gdunzip script
var gdunzip = load('res://addons/gdunzip/gdunzip.gd').new()
# Load a zip file
var loaded = gdunzip.load('res://test.zip')
# Uncompress a file, getting a PoolByteArray in return
# (or false if it failed uncompressing)
var uncompressed = gdunzip.uncompress('lorem.txt')
print('Failed uncompressing lorem.txt')
print('Failed loading zip file')
for f in gdunzip.files.values():
print('File name: ' + f['file_name'])
# "compression_method" will be either -1 for uncompressed data, or
# File.COMPRESSION_DEFLATE for deflate streams
print('Compression method: ' + str(f['compression_method']))
print('Compressed size: ' + str(f['compressed_size']))
print('Uncompressed size: ' + str(f['uncompressed_size']))
Tries to load a zip file with a given path. Returns false if it failed loading the zip, or true if it was successfull.
Try to uncompress the given file in the loaded zip. The file_name can include directories. This function returns false if the file can't be found, or if there's an error during uncompression.
Returns the compressed data for a given file name (or false if the file can't be found). Depending on the file compression it can be either uncompressed or a raw deflate stream. This function returns false if the file can't be found.
After you have loaded a file, the gdunzip instance will have a pre-filled "files" attribute. This is simply an dictionary containing the meta data for the files that reside in the zip. The dictionary is a mapping from file name (including directory) to another dictionary with the following keys: