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