#!/usr/bin/python -u
#
# p7zr library
#
# Copyright (c) 2019,2020 Hiroshi Miura <miurahr@linux.com>
# Copyright (c) 2004-2015 by Joachim Bauch, mail@joachim-bauch.de
# 7-Zip Copyright (C) 1999-2010 Igor Pavlov
# LZMA SDK Copyright (C) 1999-2010 Igor Pavlov
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.
#
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
#
import bz2
import lzma
import struct
import zlib
from abc import ABC, abstractmethod
from enum import Enum
from typing import Any, Dict, List, Optional, Tuple, Union
from Crypto.Cipher import AES
from Crypto.Random import get_random_bytes
from py7zr.exceptions import PasswordRequired, UnsupportedCompressionMethodError
from py7zr.helpers import Buffer, calculate_crc32, calculate_key
from py7zr.properties import (FILTER_ARM, FILTER_ARMTHUMB, FILTER_BZIP2, FILTER_COPY, FILTER_CRYPTO_AES256_SHA256,
FILTER_DEFLATE, FILTER_DELTA, FILTER_IA64, FILTER_LZMA, FILTER_LZMA2, FILTER_POWERPC,
FILTER_SPARC, FILTER_X86, FILTER_ZSTD, MAGIC_7Z, READ_BLOCKSIZE, CompressionMethod)
try:
import zstandard as Zstd # type: ignore
except ImportError:
Zstd = None
[docs]class ISevenZipCompressor(ABC):
[docs] @abstractmethod
def compress(self, data: Union[bytes, bytearray, memoryview]) -> bytes:
'''
Compress data (interface)
:param data: input data
:return: output data
'''
pass
[docs] @abstractmethod
def flush(self) -> bytes:
'''
Flush output buffer(interface)
:return: output data
'''
pass
[docs]class ISevenZipDecompressor(ABC):
[docs] @abstractmethod
def decompress(self, data: Union[bytes, bytearray, memoryview], max_length: int = -1) -> bytes:
'''
Decompress data (interface)
:param data: input data
:param max_length: maximum length of output data when it can respect, otherwise ignore.
:return: output data
'''
pass
[docs]class AESCompressor(ISevenZipCompressor):
'''AES Compression(Encryption) class.
It accept pre-processing filter which may be a LZMA compression.'''
AES_CBC_BLOCKSIZE = 16
def __init__(self, password: str) -> None:
self.cycles = 19 # FIXME
self.iv = get_random_bytes(16)
self.salt = b''
self.method = CompressionMethod.CRYPT_AES256_SHA256
key = calculate_key(password.encode('utf-16LE'), self.cycles, self.salt, 'sha256')
self.iv += bytes(self.AES_CBC_BLOCKSIZE - len(self.iv)) # zero padding if iv < AES_CBC_BLOCKSIZE
self.cipher = AES.new(key, AES.MODE_CBC, self.iv)
self.flushed = False
self.buf = Buffer(size=READ_BLOCKSIZE + self.AES_CBC_BLOCKSIZE * 2)
def encode_filter_properties(self):
# cycles = secrets.SystemRandom().randint(1, 23)
saltsize = len(self.salt)
ivsize = len(self.iv)
ivfirst = 1 # FIXME: it should always 1
saltfirst = 1 if len(self.salt) > 0 else 0
firstbyte = (self.cycles + (ivfirst << 6) + (saltfirst << 7)).to_bytes(1, 'little')
secondbyte = (((ivsize - 1) & 0x0f) + (((saltsize - saltfirst) << 4) & 0xf0)).to_bytes(1, 'little')
properties = firstbyte + secondbyte + self.salt + self.iv
return properties
[docs] def compress(self, data):
'''Compression + AES encryption with 16byte alignment.'''
# The size is < 16 which should be only last chunk.
# From p7zip/CPP/7zip/common/FilterCoder.cpp
# /*
# AES filters need 16-bytes alignment for HARDWARE-AES instructions.
# So we call IFilter::Filter(, size), where (size != 16 * N) only for last data block.
# AES-CBC filters need data size aligned for 16-bytes.
# So the encoder can add zeros to the end of original stream.
# Some filters (BCJ and others) don't process data at the end of stream in some cases.
# So the encoder and decoder write such last bytes without change.
# */
currentlen = len(self.buf) + len(data)
# hopefully aligned and larger than block size.
if currentlen >= 16 and (currentlen & 0x0f) == 0:
self.buf.add(data)
res = self.cipher.encrypt(self.buf.view)
self.buf.reset()
elif currentlen > 16: # when not aligned
# nextpos = (currentlen // self.AES_CBC_BLOCKSIZE) * self.AES_CBC_BLOCKSIZE
nextpos = currentlen & ~0x0f
buflen = len(self.buf)
self.buf.add(data[:nextpos - buflen])
res = self.cipher.encrypt(self.buf.view)
self.buf.set(data[nextpos - buflen:])
else: # pragma: no-cover # smaller than block size, it will processed when flush()
self.buf.add(data)
res = b''
return res
[docs] def flush(self):
if len(self.buf) > 0:
padlen = -len(self.buf) & 15 # padlen = 16 - currentlen % 16 if currentlen % 16 > 0 else 0
self.buf.add(bytes(padlen))
res = self.cipher.encrypt(self.buf.view)
self.buf.reset()
else:
res = b''
return res
[docs]class AESDecompressor(ISevenZipDecompressor):
def __init__(self, aes_properties: bytes, password: str) -> None:
firstbyte = aes_properties[0]
numcyclespower = firstbyte & 0x3f
if firstbyte & 0xc0 != 0:
saltsize = (firstbyte >> 7) & 1
ivsize = (firstbyte >> 6) & 1
secondbyte = aes_properties[1]
saltsize += (secondbyte >> 4)
ivsize += (secondbyte & 0x0f)
assert len(aes_properties) == 2 + saltsize + ivsize
salt = aes_properties[2:2 + saltsize]
iv = aes_properties[2 + saltsize:2 + saltsize + ivsize]
assert len(salt) == saltsize
assert len(iv) == ivsize
assert numcyclespower <= 24
if ivsize < 16:
iv += bytes('\x00' * (16 - ivsize), 'ascii')
key = calculate_key(password.encode('utf-16LE'), numcyclespower, salt, 'sha256')
self.cipher = AES.new(key, AES.MODE_CBC, iv)
self.buf = Buffer(size=READ_BLOCKSIZE + 16)
else:
raise UnsupportedCompressionMethodError
[docs] def decompress(self, data: Union[bytes, bytearray, memoryview], max_length: int = -1) -> bytes:
currentlen = len(self.buf) + len(data)
# when aligned to 16 bytes(expected)
if len(data) > 0 and (currentlen & 0x0f) == 0:
self.buf.add(data)
temp = self.cipher.decrypt(self.buf.view)
self.buf.reset()
return temp
elif len(data) > 0: # pragma: no-cover
# nextpos = (currentlen // 16) * 16
nextpos = currentlen & ~0x0f
buflen = len(self.buf)
temp2 = data[nextpos - buflen:]
self.buf.add(data[:nextpos - buflen])
temp = self.cipher.decrypt(self.buf.view)
self.buf.set(temp2)
return temp
elif len(self.buf) == 0: # pragma: no-cover # action flush
return b''
else: # pragma: no-cover # action padding
# align = 16
# padlen = (align - offset % align) % align
# = (align - (offset & (align - 1))) & (align - 1)
# = -offset & (align -1)
# = -offset & (16 - 1) = -offset & 15
padlen = -len(self.buf) & 15
self.buf.add(bytes(padlen))
temp3 = self.cipher.decrypt(self.buf.view) # type: bytes
self.buf.reset()
return temp3
[docs]class DeflateCompressor(ISevenZipCompressor):
def __init__(self):
self._compressor = zlib.compressobj(wbits=-15)
[docs] def compress(self, data):
return self._compressor.compress(data)
[docs] def flush(self):
return self._compressor.flush()
[docs]class DeflateDecompressor(ISevenZipDecompressor):
def __init__(self):
self.flushed = False
self._decompressor = zlib.decompressobj(wbits=-15)
[docs] def decompress(self, data: Union[bytes, bytearray, memoryview], max_length: int = -1) -> bytes:
if len(data) == 0:
if self.flushed:
return b''
else:
self.flushed = True
return self._decompressor.flush()
return self._decompressor.decompress(data)
[docs]class CopyCompressor(ISevenZipCompressor):
[docs] def compress(self, data: Union[bytes, bytearray, memoryview]) -> bytes:
return bytes(data)
[docs] def flush(self):
return b''
[docs]class CopyDecompressor(ISevenZipDecompressor):
[docs] def decompress(self, data: Union[bytes, bytearray, memoryview], max_length: int = -1) -> bytes:
return bytes(data)
[docs]class ZstdDecompressor(ISevenZipDecompressor):
def __init__(self, properties):
if Zstd is None:
raise UnsupportedCompressionMethodError
if len(properties) == 3 or len(properties) == 5:
_major = properties[0]
_minor = properties[1]
_level = properties[2]
required_version = (_major, _minor, 0)
else:
raise UnsupportedCompressionMethodError
if Zstd.ZSTD_VERSION < required_version:
raise UnsupportedCompressionMethodError
if 0 < _level <= 22:
ctc = Zstd.ZstdDecompressor() # type: ignore
else:
raise UnsupportedCompressionMethodError
self.dobj = ctc.decompressobj() # type: ignore
[docs] def decompress(self, data: Union[bytes, bytearray, memoryview], max_length: int = -1) -> bytes:
return self.dobj.decompress(data)
[docs]class ZstdCompressor(ISevenZipCompressor):
def __init__(self):
if Zstd is None:
raise UnsupportedCompressionMethodError
self._ctc = Zstd.ZstdCompressor() # type: ignore
[docs] def compress(self, data: Union[bytes, bytearray, memoryview]) -> bytes:
return self._ctc.compress(data) # type: ignore
[docs] def flush(self):
return b''
class BCJFilter:
_mask_to_allowed_number = [0, 1, 2, 4, 8, 9, 10, 12]
_mask_to_bit_number = [0, 1, 2, 2, 3, 3, 3, 3]
def __init__(self, func, readahead: int, is_encoder: bool, stream_size: int = 0):
self.is_encoder = is_encoder # type: bool
#
self.prev_mask = 0 # type: int
self.prev_pos = -5 # type: int
self.current_position = 0 # type: int
self.stream_size = stream_size # type: int # should initialize in child class
self.buffer = bytearray()
#
self._method = func
self._readahead = readahead
def _sparc_code(self):
limit = len(self.buffer) - 4
i = 0
while i <= limit:
if (self.buffer[i], self.buffer[i + 1] & 0xC0) in [(0x40, 0x00), (0x7F, 0xC0)]:
src = struct.unpack('>L', self.buffer[i:i + 4])[0] << 2
distance = self.current_position + i
if self.is_encoder:
dest = (src + distance) >> 2
else:
dest = (src - distance) >> 2
dest = (((0 - ((dest >> 22) & 1)) << 22) & 0x3FFFFFFF) | (dest & 0x3FFFFF) | 0x40000000
self.buffer[i:i + 4] = struct.pack('>L', dest)
i += 4
self.current_position = i
return i
def _ppc_code(self):
limit = len(self.buffer) - 4
i = 0
while i <= limit:
# PowerPC branch 6(48) 24(Offset) 1(Abs) 1(Link)
distance = self.current_position + i
if self.buffer[i] & 0xFC == 0x48 and self.buffer[i + 3] & 0x03 == 1:
src = struct.unpack('>L', self.buffer[i:i + 4])[0] & 0x3FFFFFC
if self.is_encoder:
dest = src + distance
else:
dest = src - distance
# lsb = int(self.buffer[i + 3]) & 0x03 == 1
dest = (0x48 << 24) | (dest & 0x03FFFFFF) | 1
self.buffer[i:i + 4] = struct.pack('>L', dest)
i += 4
self.current_position = i
return i
def _unpack_thumb(self, b: Union[bytearray, bytes, memoryview]) -> int:
return ((b[1] & 0x07) << 19) | (b[0] << 11) | ((b[3] & 0x07) << 8) | b[2]
def _pack_thumb(self, val: int):
b = bytes([(val >> 11) & 0xFF, 0xF0 | ((val >> 19) & 0x07), val & 0xFF, 0xF8 | ((val >> 8) & 0x07)])
return b
def _armt_code(self) -> int:
limit = len(self.buffer) - 4
i = 0
while i <= limit:
if self.buffer[i + 1] & 0xF8 == 0xF0 and self.buffer[i + 3] & 0xF8 == 0xF8:
src = self._unpack_thumb(self.buffer[i:i + 4]) << 1
distance = self.current_position + i + 4
if self.is_encoder:
dest = src + distance
else:
dest = src - distance
dest >>= 1
self.buffer[i:i + 4] = self._pack_thumb(dest)
i += 2
i += 2
self.current_position += i
return i
def _arm_code(self) -> int:
limit = len(self.buffer) - 4
i = 0
while i <= limit:
if self.buffer[i + 3] == 0xEB:
src = struct.unpack('<L', self.buffer[i:i + 3] + b'\x00')[0] << 2
distance = self.current_position + i + 8
if self.is_encoder:
dest = (src + distance) >> 2
else:
dest = (src - distance) >> 2
self.buffer[i:i + 3] = struct.pack('<L', dest & 0xFFFFFF)[:3]
i += 4
self.current_position += i
return i
def _x86_code(self) -> int:
size = len(self.buffer)
if size < 5:
return 0
if self.current_position - self.prev_pos > 5:
self.prev_pos = self.current_position - 5
view = memoryview(self.buffer)
limit = size - 5
buffer_pos = 0
while buffer_pos <= limit:
if view[buffer_pos] not in [0xe8, 0xe9]:
buffer_pos += 1
continue
offset = self.current_position + buffer_pos - self.prev_pos
self.prev_pos = self.current_position + buffer_pos
if offset > 5:
self.prev_mask = 0
else:
for i in range(offset):
self.prev_mask &= 0x77
self.prev_mask <<= 1
# note:
# condition (self.prev_mask >> 1) in [0, 1, 2, 4, 8, 9, 10, 12]
# is as same as
# condition _mask_to_allowed_status[(self.prev_mask >> 1) & 0x7] and (self.prev_mask >> 1) < 0x10:
# when _mask_to_allowed_status = [True, True, True, False, True, False, False, False]
#
if view[buffer_pos + 4] in [0, 0xff] and (self.prev_mask >> 1) in self._mask_to_allowed_number:
jump_target = self.buffer[buffer_pos + 1:buffer_pos + 5]
src = struct.unpack('<L', jump_target)[0]
distance = self.current_position + buffer_pos + 5
idx = self._mask_to_bit_number[self.prev_mask >> 1]
while True:
if self.is_encoder:
dest = (src + distance) & 0xffffffff # uint32 behavior
else:
dest = (src - distance) & 0xffffffff
if self.prev_mask == 0:
break
b = 0xFF & (dest >> (24 - idx * 8))
if not (b == 0 or b == 0xFF):
break
src = dest ^ ((1 << (32 - idx * 8)) - 1) & 0xffffffff
write_view = view[buffer_pos + 1:buffer_pos + 5]
write_view[0:3] = (dest & 0xFFFFFF).to_bytes(3, 'little')
write_view[3:4] = [b'\x00', b'\xff'][(dest >> 24) & 1] # (~(((dest >> 24) & 1) - 1)) & 0xFF
buffer_pos += 5
self.prev_mask = 0
else:
buffer_pos += 1
self.prev_mask |= 1
self.current_position += buffer_pos
return buffer_pos
def _decompress(self, data: Union[bytes, bytearray, memoryview], max_length: int = -1) -> bytes:
self.buffer.extend(data)
pos = self._method()
if self.current_position > self.stream_size - self._readahead:
offset = self.stream_size - self.current_position
tmp = bytes(self.buffer[:pos + offset])
self.current_position = self.stream_size
self.buffer = bytearray()
else:
tmp = bytes(self.buffer[:pos])
self.buffer = self.buffer[pos:]
return tmp
def _compress(self, data: Union[bytes, bytearray, memoryview]) -> bytes:
self.buffer.extend(data)
pos = self._method()
tmp = bytes(self.buffer[:pos])
self.buffer = self.buffer[pos:]
return tmp
def _flush(self):
return bytes(self.buffer)
[docs]class BcjSparcDecoder(ISevenZipDecompressor, BCJFilter):
def __init__(self, size: int):
super().__init__(self._sparc_code, 4, False, size)
[docs] def decompress(self, data: Union[bytes, bytearray, memoryview], max_length: int = -1) -> bytes:
return self._decompress(data)
[docs]class BcjSparcEncoder(ISevenZipCompressor, BCJFilter):
def __init__(self):
super().__init__(self._sparc_code, 4, True)
[docs] def compress(self, data: Union[bytes, bytearray, memoryview]) -> bytes:
return self._compress(data)
[docs] def flush(self):
return self._flush()
[docs]class BcjPpcDecoder(ISevenZipDecompressor, BCJFilter):
def __init__(self, size: int):
super().__init__(self._ppc_code, 4, False, size)
[docs] def decompress(self, data: Union[bytes, bytearray, memoryview], max_length: int = -1) -> bytes:
return self._decompress(data)
[docs]class BcjPpcEncoder(ISevenZipCompressor, BCJFilter):
def __init__(self):
super().__init__(self._ppc_code, 4, True)
[docs] def compress(self, data: Union[bytes, bytearray, memoryview]) -> bytes:
return self._compress(data)
[docs] def flush(self):
return self._flush()
[docs]class BcjArmtDecoder(ISevenZipDecompressor, BCJFilter):
def __init__(self, size: int):
super().__init__(self._armt_code, 4, False, size)
[docs] def decompress(self, data: Union[bytes, bytearray, memoryview], max_length: int = -1) -> bytes:
return self._decompress(data)
[docs]class BcjArmtEncoder(ISevenZipCompressor, BCJFilter):
def __init__(self):
super().__init__(self._armt_code, 4, True)
[docs] def compress(self, data: Union[bytes, bytearray, memoryview]) -> bytes:
return self._compress(data)
[docs] def flush(self):
return self._flush()
[docs]class BcjArmDecoder(ISevenZipDecompressor, BCJFilter):
def __init__(self, size: int):
super().__init__(self._arm_code, 4, False, size)
[docs] def decompress(self, data: Union[bytes, bytearray, memoryview], max_length: int = -1) -> bytes:
return self._decompress(data)
[docs]class BcjArmEncoder(ISevenZipCompressor, BCJFilter):
def __init__(self):
super().__init__(self._arm_code, 4, True)
[docs] def compress(self, data: Union[bytes, bytearray, memoryview]) -> bytes:
return self._compress(data)
[docs] def flush(self):
return self._flush()
[docs]class BCJDecoder(ISevenZipDecompressor, BCJFilter):
def __init__(self, size: int):
super().__init__(self._x86_code, 5, False, size)
[docs] def decompress(self, data: Union[bytes, bytearray, memoryview], max_length: int = -1) -> bytes:
return self._decompress(data)
[docs]class BCJEncoder(ISevenZipCompressor, BCJFilter):
def __init__(self):
super().__init__(self._x86_code, 5, True)
[docs] def compress(self, data: Union[bytes, bytearray, memoryview]) -> bytes:
return self._compress(data)
[docs] def flush(self):
return self._flush()
algorithm_class_map = {
FILTER_ZSTD: (ZstdCompressor, ZstdDecompressor),
FILTER_BZIP2: (bz2.BZ2Compressor, bz2.BZ2Decompressor),
FILTER_COPY: (CopyCompressor, CopyDecompressor),
FILTER_DEFLATE: (DeflateCompressor, DeflateDecompressor),
FILTER_CRYPTO_AES256_SHA256: (AESCompressor, AESDecompressor),
FILTER_X86: (BCJEncoder, BCJDecoder),
FILTER_ARM: (BcjArmEncoder, BcjArmDecoder),
FILTER_ARMTHUMB: (BcjArmtEncoder, BcjArmtDecoder),
FILTER_POWERPC: (BcjPpcEncoder, BcjPpcDecoder),
FILTER_SPARC: (BcjSparcEncoder, BcjSparcDecoder),
} # type: Dict[int, Tuple[Any, Any]]
def get_alternative_compressor(filter, password=None):
filter_id = filter['id']
if filter_id not in algorithm_class_map:
raise UnsupportedCompressionMethodError
elif SupportedMethods.is_crypto_id(filter_id):
return algorithm_class_map[filter_id][0](password)
else:
return algorithm_class_map[filter_id][0]()
def get_alternative_decompressor(coder: Dict[str, Any], unpacksize=None, password=None) -> Union[bz2.BZ2Decompressor, lzma.LZMADecompressor, ISevenZipDecompressor]: # noqa
filter_id = SupportedMethods.get_filter_id(coder)
# Special treatment for BCJ filters
if filter_id in [FILTER_X86, FILTER_ARM, FILTER_ARMTHUMB, FILTER_POWERPC, FILTER_SPARC]:
return algorithm_class_map[filter_id][1](size=unpacksize)
# Check supported?
if SupportedMethods.is_native_coder(coder):
raise UnsupportedCompressionMethodError('Unknown method code:{}'.format(coder['method']))
if filter_id not in algorithm_class_map:
raise UnsupportedCompressionMethodError('Unknown method filter_id:{}'.format(filter_id))
#
if SupportedMethods.is_crypto_id(filter_id):
return algorithm_class_map[filter_id][1](coder['properties'], password)
elif SupportedMethods.need_property(filter_id):
return algorithm_class_map[filter_id][1](coder['properties'])
else:
return algorithm_class_map[filter_id][1]()
[docs]class LZMA1Decompressor(ISevenZipDecompressor):
def __init__(self, filters, unpacksize):
self._decompressor = lzma.LZMADecompressor(format=lzma.FORMAT_RAW, filters=filters)
self.unpacksize = unpacksize
[docs] def decompress(self, data, max_length):
return self._decompressor.decompress(data, max_length)
def get_lzma_decompressor(coders: List[Dict[str, Any]], unpacksize: int):
filters = [] # type: List[Dict[str, Any]]
lzma1 = False
for coder in coders:
if coder['numinstreams'] != 1 or coder['numoutstreams'] != 1:
raise UnsupportedCompressionMethodError('Only a simple compression method is currently supported.')
if not SupportedMethods.is_native_coder(coder):
raise UnsupportedCompressionMethodError
properties = coder.get('properties', None)
filter_id = SupportedMethods.get_filter_id(coder)
if filter_id == FILTER_LZMA:
lzma1 = True
if properties is not None:
filters[:0] = [lzma._decode_filter_properties(filter_id, properties)] # type: ignore
else:
filters[:0] = [{'id': filter_id}]
if lzma1:
return LZMA1Decompressor(filters, unpacksize)
else:
return lzma.LZMADecompressor(format=lzma.FORMAT_RAW, filters=filters)
[docs]class DecompressorChain:
"""decompressor filter chain"""
def __init__(self, methods_map, unpacksizes):
self.filters = [] # type: List[ISevenZipDecompressor]
self._unpacksizes = []
shift = 0
prev = False
for i, r in enumerate(methods_map):
shift += 1 if r and prev else 0
prev = r
self._unpacksizes.append(unpacksizes[i - shift])
self._unpacked = [0 for _ in range(len(self._unpacksizes))]
self._unused = bytearray()
self._buf = bytearray()
def add_filter(self, filter):
self.filters.append(filter)
def _decompress(self, data, max_length: int):
for i, decompressor in enumerate(self.filters):
if self._unpacked[i] < self._unpacksizes[i]:
if isinstance(decompressor, LZMA1Decompressor):
data = decompressor.decompress(data, max_length) # always give max_length for lzma1
else:
data = decompressor.decompress(data)
self._unpacked[i] += len(data)
elif len(data) == 0:
data = b''
else:
raise EOFError
return data
def decompress(self, data, max_length: int = -1) -> bytes:
if max_length < 0:
res = self._buf + self._decompress(self._unused + data, max_length)
self._buf = bytearray()
self._unused = bytearray()
else:
current_buf_len = len(self._buf)
if current_buf_len >= max_length:
self._unused.extend(data)
res = self._buf[:max_length]
self._buf = self._buf[max_length:]
else:
if len(self._unused) > 0:
tmp = self._decompress(self._unused + data, max_length)
self._unused = bytearray()
else:
tmp = self._decompress(data, max_length)
if current_buf_len + len(tmp) <= max_length:
res = self._buf + tmp
self._buf = bytearray()
else:
res = self._buf + tmp[:max_length - current_buf_len]
self._buf = bytearray(tmp[max_length - current_buf_len:])
return res
@property
def unused_size(self):
return len(self._unused)
[docs]class SevenZipDecompressor:
"""Main decompressor object which is properly configured and bind to each 7zip folder.
because 7zip folder can have a custom compression method"""
def __init__(self, coders: List[Dict[str, Any]], packsize: int, unpacksizes: List[int], crc: Optional[int],
password: Optional[str] = None) -> None:
self.input_size = packsize
self.unpacksizes = unpacksizes
self.consumed = 0 # type: int
self.crc = crc
self.digest = None # type: Optional[int]
if len(coders) > 4:
raise UnsupportedCompressionMethodError('Maximum cascade of filters is 4 but got {}.'.format(len(coders)))
self.methods_map = [SupportedMethods.is_native_coder(coder) for coder in coders] # type: List[bool]
# --------- Hack for special combinations
# hack for LZMA1+BCJ which should be native+alternative
_bcj_filters = [FILTER_X86, FILTER_ARM, FILTER_ARMTHUMB, FILTER_POWERPC, FILTER_SPARC]
if len(coders) >= 2:
target_compressor = False
has_bcj = False
bcj_index = -1
for i, coder in enumerate(coders):
filter_id = SupportedMethods.get_filter_id(coder)
if SupportedMethods.is_compressor_id(filter_id) and filter_id != FILTER_LZMA2:
target_compressor = True
if filter_id in _bcj_filters:
has_bcj = True
bcj_index = i
if target_compressor and has_bcj:
self.methods_map[bcj_index] = False
break
# Check if password given for encrypted archive
if SupportedMethods.is_crypto_id(filter_id) and password is None:
raise PasswordRequired("Password is required for extracting given archive.")
# --------- end of Hack for special combinations
self.cchain = DecompressorChain(self.methods_map, unpacksizes)
if all(self.methods_map):
decompressor = get_lzma_decompressor(coders, unpacksizes[-1])
self.cchain.add_filter(decompressor)
elif not any(self.methods_map):
for i in range(len(coders)):
self.cchain.add_filter(get_alternative_decompressor(coders[i], unpacksizes[i], password))
elif any(self.methods_map):
for i in range(len(coders)):
if (not any(self.methods_map[:i])) and all(self.methods_map[i:]):
for j in range(i):
self.cchain.add_filter(get_alternative_decompressor(coders[j], unpacksizes[j], password))
self.cchain.add_filter(get_lzma_decompressor(coders[i:], unpacksizes[i]))
break
else:
for i in range(len(coders)):
if self.methods_map[i]:
self.cchain.add_filter(get_lzma_decompressor([coders[i]], unpacksizes[i]))
else:
self.cchain.add_filter(get_alternative_decompressor(coders[i], unpacksizes[i], password))
else:
raise UnsupportedCompressionMethodError
def decompress(self, data: bytes, max_length: Optional[int] = None) -> bytes:
self.consumed += len(data)
if max_length is not None:
folder_data = self.cchain.decompress(data, max_length=max_length)
else:
folder_data = self.cchain.decompress(data)
# calculate CRC with uncompressed data
if self.digest:
self.digest = calculate_crc32(folder_data, self.digest)
else:
self.digest = calculate_crc32(folder_data)
return folder_data
def check_crc(self):
return self.crc == self.digest
@property
def unused_size(self):
return self.cchain.unused_size
[docs]class CompressorChain:
'''compressor filter chain'''
def __init__(self, methods_map):
self.filters = [] # type: List[ISevenZipCompressor]
self.digest = 0
self.packsize = 0
self._unpacksizes = []
self.methods_map = methods_map
def add_filter(self, filter):
self.filters.append(filter)
self._unpacksizes.append(0)
def compress(self, data):
for i, compressor in enumerate(self.filters):
self._unpacksizes[i] += len(data)
data = compressor.compress(data)
self.packsize += len(data)
self.digest = calculate_crc32(data, self.digest)
return data
def flush(self):
data = None
for i, compressor in enumerate(self.filters):
if data:
self._unpacksizes[i] += len(data)
data = compressor.compress(data)
data += compressor.flush()
else:
data = compressor.flush()
self.packsize += len(data)
self.digest = calculate_crc32(data, self.digest)
return data
@property
def unpacksizes(self):
result = []
shift = 0
prev = False
for i, r in enumerate(self.methods_map):
shift += 1 if r and prev else 0
prev = r
result.insert(0, self._unpacksizes[i - shift])
return result
[docs]class SevenZipCompressor:
"""Main compressor object to configured for each 7zip folder."""
__slots__ = ['filters', 'compressor', 'coders', 'cchain', 'methods_map']
def __init__(self, filters=None, password=None):
if filters is None:
self.filters = [{"id": lzma.FILTER_LZMA2, "preset": 7 | lzma.PRESET_EXTREME}]
else:
self.filters = filters
if len(self.filters) > 4:
raise UnsupportedCompressionMethodError('Maximum cascade of filters is 4 but got {}.'.format(len(self.filters)))
self.methods_map = [SupportedMethods.is_native_filter(filter) for filter in self.filters]
self.coders = []
if all(self.methods_map) and SupportedMethods.is_compressor(self.filters[-1]): # all native
self.cchain = CompressorChain(self.methods_map)
self._set_native_compressors_coders(self.filters)
return
#
for i, f in enumerate(self.filters):
if f['id'] == FILTER_X86:
self.methods_map[i] = False
#
self.cchain = CompressorChain(self.methods_map)
if not any(self.methods_map): # all alternative
for filter in filters:
self._set_alternate_compressors_coders(filter, password)
elif SupportedMethods.is_crypto(self.filters[-1]) and all(self.methods_map[:-1]): # Crypto + native compression
self._set_native_compressors_coders(self.filters[:-1])
self._set_alternate_compressors_coders(self.filters[-1], password)
else:
raise UnsupportedCompressionMethodError
def _set_native_compressors_coders(self, filters):
self.cchain.add_filter(lzma.LZMACompressor(format=lzma.FORMAT_RAW, filters=filters))
for filter in filters:
self.coders.insert(0, SupportedMethods.get_coder(filter))
def _set_alternate_compressors_coders(self, filter, password=None):
compressor = get_alternative_compressor(filter, password)
if SupportedMethods.is_crypto(filter):
properties = compressor.encode_filter_properties()
elif SupportedMethods.need_property(filter['id']):
if filter['id'] == FILTER_ZSTD:
level = 3
properties = struct.pack("BBBBB", Zstd.ZSTD_VERSION[0], Zstd.ZSTD_VERSION[1], level, 0, 0)
else:
properties = None
self.cchain.add_filter(compressor)
self.coders.insert(0, {'method': SupportedMethods.get_method_id(filter),
'properties': properties, 'numinstreams': 1, 'numoutstreams': 1})
def compress(self, data):
return self.cchain.compress(data)
def flush(self):
return self.cchain.flush()
@property
def digest(self):
return self.cchain.digest
@property
def unpacksizes(self):
return self.cchain.unpacksizes
@property
def packsize(self):
return self.cchain.packsize
[docs]class MethodsType(Enum):
compressor = 0
filter = 1
crypto = 2
[docs]class SupportedMethods:
"""Hold list of methods."""
formats = [{'name': "7z", 'magic': MAGIC_7Z}]
methods = [{'id': CompressionMethod.COPY, 'name': 'COPY', 'native': False, 'need_prop': False,
'filter_id': FILTER_COPY, 'type': MethodsType.compressor},
{'id': CompressionMethod.LZMA2, 'name': "LZMA2", 'native': True, 'need_prop': True,
'filter_id': FILTER_LZMA2, 'type': MethodsType.compressor},
{'id': CompressionMethod.DELTA, 'name': "DELTA", 'native': True, 'need_prop': True,
'filter_id': FILTER_DELTA, 'type': MethodsType.filter},
{'id': CompressionMethod.LZMA, 'name': "LZMA", 'native': True, 'need_prop': True,
'filter_id': FILTER_LZMA, 'type': MethodsType.compressor},
{'id': CompressionMethod.P7Z_BCJ, 'name': "BCJ", 'native': True, 'need_prop': False,
'filter_id': FILTER_X86, 'type': MethodsType.filter},
{'id': CompressionMethod.BCJ_PPC, 'name': 'PPC', 'native': True, 'need_prop': False,
'filter_id': FILTER_POWERPC, 'type': MethodsType.filter},
{'id': CompressionMethod.BCJ_IA64, 'name': 'IA64', 'native': True, 'need_prop': False,
'filter_id': FILTER_IA64, 'type': MethodsType.filter},
{'id': CompressionMethod.BCJ_ARM, 'name': "ARM", 'native': True, 'need_prop': False,
'filter_id': FILTER_ARM, 'type': MethodsType.filter},
{'id': CompressionMethod.BCJ_ARMT, 'name': "ARMT", 'native': True, 'need_prop': False,
'filter_id': FILTER_ARMTHUMB, 'type': MethodsType.filter},
{'id': CompressionMethod.BCJ_SPARC, 'name': 'SPARC', 'native': True, 'need_prop': False,
'filter_id': FILTER_SPARC, 'type': MethodsType.filter},
{'id': CompressionMethod.MISC_DEFLATE, 'name': 'DEFLATE', 'native': False, 'need_prop': False,
'filter_id': FILTER_DEFLATE, 'type': MethodsType.compressor},
{'id': CompressionMethod.MISC_BZIP2, 'name': 'BZip2', 'native': False, 'need_prop': False,
'filter_id': FILTER_BZIP2, 'type': MethodsType.compressor},
{'id': CompressionMethod.MISC_ZSTD, 'name': 'ZStandard', 'native': False, 'need_prop': True,
'filter_id': FILTER_ZSTD, 'type': MethodsType.compressor},
{'id': CompressionMethod.CRYPT_AES256_SHA256, 'name': '7zAES', 'native': False, 'need_prop': True,
'filter_id': FILTER_CRYPTO_AES256_SHA256, 'type': MethodsType.crypto},
]
@classmethod
def _find_method(cls, key_id, key_value):
return next((item for item in cls.methods if item[key_id] == key_value), None)
@classmethod
def get_filter_id(cls, coder):
return cls._find_method('id', coder['method'])['filter_id']
@classmethod
def is_native_filter(cls, filter) -> bool:
method = cls._find_method('filter_id', filter['id'])
if method is None:
raise UnsupportedCompressionMethodError
return method['native']
@classmethod
def is_compressor(cls, filter):
method = cls._find_method('filter_id', filter['id'])
return method['type'] == MethodsType.compressor
@classmethod
def is_compressor_id(cls, filter_id):
method = cls._find_method('filter_id', filter_id)
return method['type'] == MethodsType.compressor
@classmethod
def is_native_coder(cls, coder) -> bool:
method = cls._find_method('id', coder['method'])
if method is None:
raise UnsupportedCompressionMethodError
return method['native']
@classmethod
def is_crypto(cls, filter) -> bool:
method = cls._find_method('filter_id', filter['id'])
if method is None:
raise UnsupportedCompressionMethodError
return method['type'] == MethodsType.crypto
@classmethod
def need_property(cls, filter_id):
method = cls._find_method('filter_id', filter_id)
if method is None:
raise UnsupportedCompressionMethodError
return method['need_prop']
@classmethod
def is_crypto_id(cls, filter_id) -> bool:
method = cls._find_method('filter_id', filter_id)
if method is None:
raise UnsupportedCompressionMethodError
return method['type'] == MethodsType.crypto
@classmethod
def get_method_id(cls, filter) -> bytes:
method = cls._find_method('filter_id', filter['id'])
if method is None:
raise UnsupportedCompressionMethodError
return method['id']
@classmethod
def get_coder(cls, filter) -> Dict[str, Any]:
method = cls.get_method_id(filter)
if filter['id'] in [lzma.FILTER_LZMA1, lzma.FILTER_LZMA2, lzma.FILTER_DELTA]:
properties = lzma._encode_filter_properties(filter) # type: Optional[bytes] # type: ignore # noqa
else:
properties = None
return {'method': method, 'properties': properties, 'numinstreams': 1, 'numoutstreams': 1}
def get_methods_names_string(coders_lists: List[List[dict]]) -> str:
# list of known method names with a display priority order
methods_namelist = ['LZMA2', 'LZMA', 'BZip2', 'DEFLATE', 'DEFLATE64*', 'delta', 'COPY', 'ZStandard', 'LZ4*', 'BCJ2*',
'BCJ', 'ARM', 'ARMT', 'IA64', 'PPC', 'SPARC', '7zAES']
unsupported_methods = {CompressionMethod.P7Z_BCJ2: 'BCJ2*',
CompressionMethod.MISC_LZ4: 'LZ4*',
CompressionMethod.MISC_DEFLATE64: 'DEFLATE64*'}
methods_names = []
for coders in coders_lists:
for coder in coders:
for m in SupportedMethods.methods:
if coder['method'] == m['id']:
methods_names.append(m['name'])
if coder['method'] in unsupported_methods:
methods_names.append(unsupported_methods[coder['method']])
return ', '.join(filter(lambda x: x in methods_names, methods_namelist))
