pycatfilealt.py

   1 import os
   2 import sys
   3 import logging
   4 import tarfile
   5 import zlib
   6 import argparse
   7 from io import BytesIO
   8
   9 # Configure logging
  10 logging.basicConfig(level=logging.INFO)
  11 logger = logging.getLogger(__name__)
  12
  13 class CatFilePacker:
  14     def __init__(self, checksum_type='crc32'):
  15         self.checksum_type = checksum_type
  16
  17     def pack_from_tar(self, tar_path, catfile_path):
  18         try:
  19             with tarfile.open(tar_path, 'r') as tar, open(catfile_path, 'wb') as catfile:
  20                 for member in tar.getmembers():
  21                     if member.isfile():
  22                         file_data = tar.extractfile(member).read()
  23                         packed_data = self._pack_file_data(file_data, member)
  24                         catfile.write(packed_data)
  25             return True
  26         except tarfile.TarError as e:
  27             logger.error(f"Tar file error: {e}")
  28             return False
  29         except IOError as e:
  30             logger.error(f"I/O error: {e}")
  31             return False
  32         except Exception as e:
  33             logger.error(f"Unexpected error: {e}")
  34             return False
  35
  36     def _pack_file_data(self, data, member):
  37         metadata = self._create_metadata(member)
  38         checksum = self._calculate_checksum(data)
  39         metadata_length = len(metadata).to_bytes(4, byteorder='little')
  40         data_length = len(data).to_bytes(4, byteorder='little')
  41         packed_data = metadata_length + metadata + data_length + data + checksum
  42         return packed_data
  43
  44     def _create_metadata(self, member):
  45         name = member.name.encode('utf-8')
  46         size = member.size.to_bytes(8, byteorder='little')
  47         mtime = member.mtime.to_bytes(8, byteorder='little')
  48         mode = member.mode.to_bytes(4, byteorder='little')
  49         metadata = name + size + mtime + mode
  50         return metadata
  51
  52     def _calculate_checksum(self, data):
  53         if self.checksum_type == 'crc32':
  54             checksum = zlib.crc32(data).to_bytes(4, byteorder='little')
  55         else:
  56             checksum = b'\x00' * 4  # Placeholder for unsupported checksum types
  57         return checksum
  58
  59 if __name__ == "__main__":
  60     parser = argparse.ArgumentParser(description='Pack files from a TAR archive into a CAT file.')
  61     parser.add_argument('tar_path', help='Path to the TAR file to pack')
  62     parser.add_argument('catfile_path', help='Path to the CAT file to create')
  63     args = parser.parse_args()
  64
  65     packer = CatFilePacker(checksum_type='crc32')
  66     success = packer.pack_from_tar(args.tar_path, args.catfile_path)
  67     if success:
  68         logger.info("Packing completed successfully.")
  69     else:
  70         logger.error("Packing failed.")