It's really not that hard. You just check the magic number and if it's the new one, skip 4 words. No need to understand the internals of the header.
On Oct 3, 2017 08:06, "Barry Warsaw" <ba...@python.org> wrote: > Guido van Rossum wrote: > > There have been no further comments. PEP 552 is now accepted. > > > > Congrats, Benjamin! Go ahead and send your implementation for > review.Oops. > > Let me try that again. > > While I'm very glad PEP 552 has been accepted, it occurs to me that it > will now be more difficult to parse the various pyc file formats from > Python. E.g. I used to be able to just open the pyc in binary mode, > read all the bytes, and then lop off the first 8 bytes to get to the > code object. With the addition of the source file size, I now have to > (maybe, if I have to also read old-style pyc files) lop off the front 12 > bytes, but okay. > > With PEP 552, I have to do a lot more work to just get at the code > object. How many bytes at the front of the file do I need to skip past? > What about all the metadata at the front of the pyc, how do I interpret > that if I want to get at it from Python code? > > Should the PEP 552 implementation add an API, probably to > importlib.util, that would understand all current and future formats? > Something like this perhaps? > > class PycFileSpec: > magic_number: bytes > timestamp: Optional[bytes] # maybe an int? datetime? > source_size: Optional[bytes] > bit_field: Optional[bytes] > code_object: bytes > > def parse_pyc(path: str) -> PycFileSpec: > > Cheers, > -Barry > > _______________________________________________ > Python-Dev mailing list > Python-Dev@python.org > https://mail.python.org/mailman/listinfo/python-dev > Unsubscribe: https://mail.python.org/mailman/options/python-dev/ > guido%40python.org >
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