add encrption module

fix bug in zstd compression warp code
fix bug when showing compression inforamtion

testenc.py

@@ -0,0 +1,100 @@
+from game_backuper.compress import CompressConfig
+from game_backuper.enc import DecryptException, EncFile
+from os import urandom, remove
+from hashlib import sha512
+from zlib import crc32
+
+
+datalen = 4096
+data = urandom(datalen)
+a = sha512()
+a.update(data)
+with EncFile('a.txt', 'wb', a.digest()) as f:
+    f.write(data)
+    key = f.key
+    iv = f.iv
+    crc = f.crc32
+    print(crc)
+    crc2 = '{:08x}'.format(crc32(data[:1024]))
+    print(crc2)
+    assert crc == crc2
+with EncFile('a.txt', 'rb', a.digest(), key, iv, datalen, crc) as f:
+    d = f.read()
+    assert d == data
+with EncFile('a.txt', 'rb', b'', key, iv, datalen, crc) as f:
+    try:
+        d = f.read()
+        assert False
+    except DecryptException:
+        pass
+remove('a.txt')
+with EncFile('a.txt', 'wb', b'', compress=CompressConfig('gzip', 9)) as f:
+    f.write(data)
+    f.flush()
+    key = f.key
+    iv = f.iv
+le = f.tell()
+crc = f.crc32
+with EncFile('a.txt', 'rb', b'', key, iv, le, crc, compress=CompressConfig('gzip')) as f:  # noqa: E501
+    assert data == f.read()
+remove('a.txt')
+with EncFile('a.txt', 'wb', b'', compress=CompressConfig('bzip2', 1)) as f:
+    f.write(data)
+    f.flush()
+    key = f.key
+    iv = f.iv
+le = f.tell()
+crc = f.crc32
+with EncFile('a.txt', 'rb', b'', key, iv, le, crc, CompressConfig('bzip2', 1)) as f:  # noqa: E501
+    assert data == f.read()
+remove('a.txt')
+with EncFile('a.txt', 'wb', b'', compress=CompressConfig('lzma', 1)) as f:
+    f.write(data)
+    f.flush()
+    key = f.key
+    iv = f.iv
+le = f.tell()
+crc = f.crc32
+with EncFile('a.txt', 'rb', b'', key, iv, le, crc, CompressConfig('lzma', 1)) as f:  # noqa: E501
+    assert data == f.read()
+remove('a.txt')
+with EncFile('a.txt', 'wb', b'', compress=CompressConfig('lzip', 1)) as f:
+    f.write(data)
+    f.flush()
+    key = f.key
+    iv = f.iv
+le = f.tell()
+crc = f.crc32
+with EncFile('a.txt', 'rb', b'', key, iv, le, crc, CompressConfig('lzip', 1)) as f:  # noqa: E501
+    assert data == f.read()
+remove('a.txt')
+with EncFile('a.txt', 'wb', b'', compress=CompressConfig('zstd', 1)) as f:
+    f.write(data)
+    f.flush()
+    key = f.key
+    iv = f.iv
+le = f.tell()
+crc = f.crc32
+with EncFile('a.txt', 'rb', b'', key, iv, le, crc, CompressConfig('zstd', 1)) as f:  # noqa: E501
+    assert data == f.read()
+remove('a.txt')
+with EncFile('a.txt', 'wb', b'', compress=CompressConfig('snappy', 1)) as f:
+    f.write(data)
+    f.flush()
+    key = f.key
+    iv = f.iv
+le = f.tell()
+crc = f.crc32
+with EncFile('a.txt', 'rb', b'', key, iv, le, crc, CompressConfig('snappy', 1)) as f:  # noqa: E501
+    assert data == f.read()
+remove('a.txt')
+with EncFile('a.txt', 'wb', b'', compress=CompressConfig('brotli', 1)) as f:
+    f.write(data)
+    f.flush()
+    key = f.key
+    iv = f.iv
+le = f.tell()
+crc = f.crc32
+with EncFile('a.txt', 'rb', b'', key, iv, le, crc, CompressConfig('brotli', 1)) as f:  # noqa: E501
+    assert data == f.read()
+remove('a.txt')