def __compress(self, compression: str, data: bytes) -> bytes:
"""
Given data and an optional compression scheme, compress the data.
Parameters:
compression - A string specifying the compression used. Should
be of the form 'l7zz' or 'none'. The python value
None will also be recognized as 'none'.
data - Binary string representing data to transform.
Returns:
binary string representing transformed data
"""
if data is None:
return None
if compression:
if compression is None or compression == 'none':
# This isn't compressed
return data
elif compression == 'lz77':
# This is a compressed new-style packet
lz = Lz77()
return lz.compress(data)
else:
raise EAmuseException(f'Unknown compression {compression}')
# No compression
return data
def test_huge_data_random(self) -> None:
lz77 = Lz77()
data = os.urandom(1 * 1024 * 1024)
compresseddata = lz77.compress(data)
self.assertNotEqual(data, compresseddata)
decompresseddata = lz77.decompress(compresseddata)
self.assertEqual(data, decompresseddata)
def test_large_data_random(self) -> None:
lz77 = Lz77()
data = bytes([random.randint(0, 255) for _ in range(100 * 1024)])
compresseddata = lz77.compress(data)
self.assertNotEqual(data, compresseddata)
decompresseddata = lz77.decompress(compresseddata)
self.assertEqual(data, decompresseddata)
def read_file(self, filename: str) -> bytes:
(fileoffset, uncompressedsize, compressedsize) = self.__files[filename]
if compressedsize == uncompressedsize:
# Just stored
return self.__data[fileoffset:(fileoffset + compressedsize)]
else:
# Compressed
lz77 = Lz77()
return lz77.decompress(self.__data[fileoffset:(fileoffset + compressedsize)])
def test_texture(self) -> None:
lz77 = Lz77()
data = get_fixture("rawdata")
compresseddata = lz77.compress(data)
self.assertNotEqual(data, compresseddata)
self.assertTrue(len(compresseddata) < len(data))
decompresseddata = lz77.decompress(compresseddata)
self.assertEqual(data, decompresseddata)
def test_lorem_ipsum(self) -> None:
lz77 = Lz77()
data = get_fixture("lorem.txt")
compresseddata = lz77.compress(data)
self.assertNotEqual(data, compresseddata)
self.assertTrue(len(compresseddata) < len(data))
decompresseddata = lz77.decompress(compresseddata)
self.assertEqual(data, decompresseddata)
def test_declaration(self) -> None:
lz77 = Lz77()
data = get_fixture("declaration.txt")
compresseddata = lz77.compress(data)
self.assertNotEqual(data, compresseddata)
self.assertTrue(len(compresseddata) < len(data))
decompresseddata = lz77.decompress(compresseddata)
self.assertEqual(data, decompresseddata)
def test_known_compression(self) -> None:
"""
Specifically tests for ability to compress an overlap,
verifies that we don't regress on known compressions.
"""
lz77 = Lz77()
data = b"abcabcabcabc"
compresseddata = lz77.compress(data)
self.assertEqual(b"\x07abc\x006\x00\x00", compresseddata)
decompresseddata = lz77.decompress(compresseddata)
self.assertEqual(data, decompresseddata)
def read_file(self, filename: str) -> bytes:
# If this is a texture folder, first we need to grab the texturelist.xml file
# to figure out if this is compressed or not.
decompress = False
texlist = self.__get_texlist_for_file(filename)
if texlist is not None and texlist.name == 'texturelist':
if texlist.attribute('compress') == 'avslz':
# We should decompress!
decompress = True
filedata = self.__files[filename]
if decompress:
uncompressed_size, compressed_size = struct.unpack(
'>II', filedata[0:8])
if len(filedata) == compressed_size + 8:
lz77 = Lz77()
filedata = lz77.decompress(filedata[8:])
else:
raise Exception('Unrecognized compression!')
if self.__decode_binxml and os.path.splitext(filename)[1] == '.xml':
benc = BinaryEncoding()
filexml = benc.decode(filedata)
if filexml is not None:
filedata = str(filexml).encode('utf-8')
if self.__decode_textures and filename in self.__mappings and filename in self.__sizes:
fmt = self.__mappings.get(filename)
wh = self.__sizes.get(filename)
if fmt == "argb8888rev":
if len(filedata) < (wh[0] * wh[1] * 4):
left = (wh[0] * wh[1] * 4) - len(filedata)
filedata = filedata + b'\x00' * left
img = Image.frombytes('RGBA', wh, filedata, 'raw', 'BGRA')
b = io.BytesIO()
img.save(b, format='PNG')
filedata = b.getvalue()
return filedata
