Python bz2 uncompressed file size

Question

I am using Python 2.7. I have a .bz2 file, and I need to figure out the uncompressed file size of its component file without actually decompressing it. I have found ways to

Answer 1

I suspect this is impossible due to the nature of bz2 format and compressing techniques it uses. Here is a quite good description of the both format and the algorithms http://en.wikipedia.org/wiki/Bzip2#File_format

You will never know original data size until you decompress it.