How to use the apkutils.apkfile.BadZipFile function in apkutils

"ZIP_STORED", "ZIP_DEFLATED", "ZIP_BZIP2", "ZIP_LZMA",
           "is_zipfile", "ZipInfo", "ZipFile", "PyZipFile", "LargeZipFile"]


class BadZipFile(Exception):
    pass


class LargeZipFile(Exception):
    """
    Raised when writing a zipfile, the zipfile requires ZIP64 extensions
    and those extensions are disabled.
    """


error = BadZipfile = BadZipFile      # Pre-3.2 compatibility names


ZIP64_LIMIT = (1 << 31) - 1
ZIP_FILECOUNT_LIMIT = (1 << 16) - 1
ZIP_MAX_COMMENT = (1 << 16) - 1

# constants for Zip file compression methods
ZIP_STORED = 0
ZIP_DEFLATED = 8
ZIP_BZIP2 = 12
ZIP_LZMA = 14
# Other ZIP compression methods not supported

DEFAULT_VERSION = 20
ZIP64_VERSION = 45
BZIP2_VERSION = 46

try:
        fpin.seek(offset - sizeEndCentDir64Locator, 2)
    except OSError:
        # If the seek fails, the file is not large enough to contain a ZIP64
        # end-of-archive record, so just return the end record we were given.
        return endrec

    data = fpin.read(sizeEndCentDir64Locator)
    if len(data) != sizeEndCentDir64Locator:
        return endrec
    sig, diskno, reloff, disks = struct.unpack(structEndArchive64Locator, data)
    if sig != stringEndArchive64Locator:
        return endrec

    if diskno != 0 or disks != 1:
        raise BadZipFile("zipfiles that span multiple disks are not supported")

    # Assume no 'zip64 extensible data'
    fpin.seek(offset - sizeEndCentDir64Locator - sizeEndCentDir64, 2)
    data = fpin.read(sizeEndCentDir64)
    if len(data) != sizeEndCentDir64:
        return endrec
    sig, sz, create_version, read_version, disk_num, disk_dir, \
        dircount, dircount2, dirsize, diroffset = \
        struct.unpack(structEndArchive64, data)
    if sig != stringEndArchive64:
        return endrec

    # Update the original endrec using data from the ZIP64 record
    endrec[_ECD_SIGNATURE] = sig
    endrec[_ECD_DISK_NUMBER] = disk_num
    endrec[_ECD_DISK_START] = disk_dir

# Zip 2.7: compressed patched data
                raise NotImplementedError(
                    "compressed patched data (flag bit 5)")

            if zinfo.flag_bits & 0x40:
                # strong encryption
                raise NotImplementedError("strong encryption (flag bit 6)")

            if zinfo.flag_bits & 0x800:
                # UTF-8 filename
                fname_str = fname.decode("utf-8")
            else:
                fname_str = fname.decode("cp437")

            if fname_str != zinfo.orig_filename:
                raise BadZipFile(
                    'File name in directory %r and header %r differ.'
                    % (zinfo.orig_filename, fname))

            return ZipExtFile(zef_file, mode, zinfo, None, True)
        except Exception as ignore:
            zef_file.close()
            raise

zef_file = _SharedFile(
            self.fp, zinfo.header_offset, self._fpclose, self._lock)

        try:
            # Skip the file header:
            fheader = zef_file.read(sizeFileHeader)

            if len(fheader) != sizeFileHeader:
                raise BadZipFile("Truncated file header")

            fheader = struct.unpack(structFileHeader, fheader)
            # print(fheader)

            if fheader[_FH_SIGNATURE] != stringFileHeader:
                raise BadZipFile("Bad magic number for file header")

            # 注意：头部的文件长度可能会被修改
            len_fname = fheader[_FH_FILENAME_LENGTH]
            if len_fname > 256:
                # 自动修正文件名长度，但是，不能保证解压成功
                len_fname = len(zinfo.orig_filename)

            fname = zef_file.read(len_fname)

            if fheader[_FH_EXTRA_FIELD_LENGTH]:
                zef_file.read(fheader[_FH_EXTRA_FIELD_LENGTH])

            # zinfo.flag_bits ^= zinfo.flag_bits % 2

            if zinfo.flag_bits & 0x20:
                # Zip 2.7: compressed patched data

if self.debug > 2:
            inferred = concat + offset_cd
            print("given, inferred, offset", offset_cd, inferred, concat)
        # self.start_dir:  Position of start of central directory
        self.start_dir = offset_cd + concat
        fp.seek(self.start_dir, 0)
        data = fp.read(size_cd)
        fp = io.BytesIO(data)
        total = 0
        while total < size_cd:
            centdir = fp.read(sizeCentralDir)
            if len(centdir) != sizeCentralDir:
                raise BadZipFile("Truncated central directory")
            centdir = struct.unpack(structCentralDir, centdir)
            if centdir[_CD_SIGNATURE] != stringCentralDir:
                raise BadZipFile("Bad magic number for central directory")
            if self.debug > 2:
                print(centdir)
            filename = fp.read(centdir[_CD_FILENAME_LENGTH])
            flags = centdir[5]
            if flags & 0x800:
                # UTF-8 file names extension
                filename = filename.decode('utf-8')
            else:
                # Historical ZIP filename encoding
                filename = filename.decode('cp437')
            # Create ZipInfo instance to store file information
            x = ZipInfo(filename)
            x.extra = fp.read(centdir[_CD_EXTRA_FIELD_LENGTH])
            x.comment = fp.read(centdir[_CD_COMMENT_LENGTH])
            x.header_offset = centdir[_CD_LOCAL_HEADER_OFFSET]
            (x.create_version, x.create_system, x.extract_version, x.reserved,

zinfo = name
        else:
            # Get info object for name
            zinfo = self.getinfo(name)

        self._fileRefCnt += 1

        zef_file = _SharedFile(
            self.fp, zinfo.header_offset, self._fpclose, self._lock)

        try:
            # Skip the file header:
            fheader = zef_file.read(sizeFileHeader)

            if len(fheader) != sizeFileHeader:
                raise BadZipFile("Truncated file header")

            fheader = struct.unpack(structFileHeader, fheader)
            # print(fheader)

            if fheader[_FH_SIGNATURE] != stringFileHeader:
                raise BadZipFile("Bad magic number for file header")

            # 注意：头部的文件长度可能会被修改
            len_fname = fheader[_FH_FILENAME_LENGTH]
            if len_fname > 256:
                # 自动修正文件名长度，但是，不能保证解压成功
                len_fname = len(zinfo.orig_filename)

            fname = zef_file.read(len_fname)

            if fheader[_FH_EXTRA_FIELD_LENGTH]:

#     concat -= (sizeEndCentDir64 + sizeEndCentDir64Locator)
        concat = 0

        if self.debug > 2:
            inferred = concat + offset_cd
            print("given, inferred, offset", offset_cd, inferred, concat)
        # self.start_dir:  Position of start of central directory
        self.start_dir = offset_cd + concat
        fp.seek(self.start_dir, 0)
        data = fp.read(size_cd)
        fp = io.BytesIO(data)
        total = 0
        while total < size_cd:
            centdir = fp.read(sizeCentralDir)
            if len(centdir) != sizeCentralDir:
                raise BadZipFile("Truncated central directory")
            centdir = struct.unpack(structCentralDir, centdir)
            if centdir[_CD_SIGNATURE] != stringCentralDir:
                raise BadZipFile("Bad magic number for central directory")
            if self.debug > 2:
                print(centdir)
            filename = fp.read(centdir[_CD_FILENAME_LENGTH])
            flags = centdir[5]
            if flags & 0x800:
                # UTF-8 file names extension
                filename = filename.decode('utf-8')
            else:
                # Historical ZIP filename encoding
                filename = filename.decode('cp437')
            # Create ZipInfo instance to store file information
            x = ZipInfo(filename)
            x.extra = fp.read(centdir[_CD_EXTRA_FIELD_LENGTH])