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@Chase-san
Created September 5, 2021 22:08
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A tool for de/compressing No Man's Sky save files.
#!/usr/bin/python3
# Copyright 2021, Robert Maupin
# Copying and distribution of this file, with or without modification, are
# permitted in any medium without royalty, provided the copyright notice and
# this notice are preserved. This file is offered as-is, without any warranty.
import io
import os
import lz4.block
import math
import sys
from glob import glob
FILE_PATH = os.path.dirname(os.path.realpath(__file__))
def uint32(data: bytes) -> int:
"""Convert 4 bytes to a little endian unsigned integer."""
return int.from_bytes(data, byteorder='little', signed=False) & 0xffffffff
def byte4(data: int):
"""Convert unsigned 32 bit integer to 4 bytes."""
return data.to_bytes(4, byteorder='little', signed=False)
# The important part
def decompress(data):
"""Decompresses the given save bytes."""
size = len(data)
din = io.BytesIO(data)
out = bytearray()
while din.tell() < size:
magic = uint32(din.read(4))
if magic != 0xfeeda1e5:
print("Invalid Block, bad file")
return bytes() # some unsupported format
compressedSize = uint32(din.read(4))
uncompressedSize = uint32(din.read(4))
din.seek(4, 1) # skip 4 bytes
out += lz4.block.decompress(din.read(compressedSize), uncompressed_size=uncompressedSize)
return out
# The important part, part 2
def compress(data):
"""Compresses the given save bytes."""
size = len(data)
din = io.BytesIO(data)
out = bytearray()
while din.tell() < size:
uncompressedSize = min([0x80000, size - din.tell()])
block = lz4.block.compress(din.read(uncompressedSize), store_size=False)
out += byte4(0xfeeda1e5)
out += byte4(len(block))
out += byte4(uncompressedSize)
out += byte4(0)
out += block
return out
def readFile(path):
fin = open(path, "rb")
data = fin.read()
fin.close()
return data
def writeFile(path, data):
fout = open(path, "wb")
fout.write(data)
fout.close()
def findSaveGames():
"""Finds all saves on windows."""
return glob("C:\\Users\\*\\AppData\\Roaming\\HelloGames\\NMS\\*\\save*.hg")
def usage(name):
print("No Man's Sky Save Tool v0.1")
print("Copyright (c) 2021 Robert Maupin. Permissive License.")
print("Usage: %s compress <input> <output>" % os.path.basename(name))
print("Usage: %s decompress <input> <output>" % os.path.basename(name))
print("Usage: %s list" % os.path.basename(name))
print(" compress Decompress a given 'No Man's Sky' save file.")
print(" decompress Compress a given 'No Man's Sky' save file.")
print(" list Searchs for save files and outputs what files were found.")
def main():
args = sys.argv
if len(args) == 2:
if args[1] == "l" or args[1] == "list":
for file in findSaveGames():
print(file)
return
if len(args) == 4:
if args[1] == "c" or args[1] == "compress":
writeFile(args[3], compress(readFile(args[2])))
print("done")
return
if args[1] == "d" or args[1] == "decompress":
writeFile(args[3], decompress(readFile(args[2])))
print("done")
return
usage(args[0])
main()
@Chase-san
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Chase-san commented Sep 5, 2021

You will need python3 and to run pip install lz4 to use this script properly.

Specifically python3 nmssavetool.py decompress <input> <output>.

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