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#!/usr/bin/python -u
#
# p7zr library
#
# Copyright (c) 2019 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 lzma
import zlib
from abc import ABC, abstractmethod
from typing import Any, Dict, List, Union
from py7zr import UnsupportedCompressionMethodError
from py7zr.helpers import Buffer, calculate_key
from py7zr.properties import READ_BLOCKSIZE, CompressionMethod
try:
import zstandard as Zstd # type: ignore
except ImportError:
Zstd = None
class ISevenZipCompressor(ABC):
@abstractmethod
def compress(self, data: Union[bytes, bytearray, memoryview]) -> bytes:
pass
@abstractmethod
def flush(self) -> bytes:
pass
class ISevenZipDecompressor(ABC):
@abstractmethod
def decompress(self, data: Union[bytes, bytearray, memoryview], max_length: int = -1) -> bytes:
pass
class DeflateDecompressor(ISevenZipDecompressor):
def __init__(self):
self.buf = b''
self._decompressor = zlib.decompressobj(-15)
def decompress(self, data: Union[bytes, bytearray, memoryview], max_length: int = -1):
if max_length < 0:
res = self.buf + self._decompressor.decompress(data)
self.buf = b''
else:
tmp = self.buf + self._decompressor.decompress(data)
res = tmp[:max_length]
self.buf = tmp[max_length:]
return res
class CopyDecompressor(ISevenZipDecompressor):
def __init__(self):
self._buf = bytes()
def decompress(self, data: Union[bytes, bytearray, memoryview], max_length: int = -1) -> bytes:
if max_length < 0:
length = len(data)
else:
length = min(len(data), max_length)
buflen = len(self._buf)
if length > buflen:
res = self._buf + data[:length - buflen]
self._buf = data[length - buflen:]
else:
res = self._buf[:length]
self._buf = self._buf[length:] + data
return res
class ZstdDecompressor(ISevenZipDecompressor):
def __init__(self):
if Zstd is None:
raise UnsupportedCompressionMethodError
self.buf = b'' # type: bytes
self._ctc = Zstd.ZstdDecompressor() # type: ignore
def decompress(self, data: Union[bytes, bytearray, memoryview], max_length: int = -1) -> bytes:
dobj = self._ctc.decompressobj() # type: ignore
if max_length < 0:
res = self.buf + dobj.decompress(data)
self.buf = b''
else:
tmp = self.buf + dobj.decompress(data)
res = tmp[:max_length]
self.buf = tmp[max_length:]
return res
class ZstdCompressor(ISevenZipCompressor):
def __init__(self):
if Zstd is None:
raise UnsupportedCompressionMethodError
self._ctc = Zstd.ZstdCompressor() # type: ignore
def compress(self, data: Union[bytes, bytearray, memoryview]) -> bytes:
return self._ctc.compress(data) # type: ignore
def flush(self):
pass
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