stream does not work properly on opened small files

[FelipeLema]

using the following image (icon-32.png)

the following code fails

import puremagic

with open(r"icon-32.png", "rb") as file:
    print(puremagic.magic_stream(file))

here's the error

Traceback (most recent call last):
  File "/home/…/./playing-with-puremagic", line 4, in <module>
    print(puremagic.magic_stream(file))
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/…/.venv/lib/python3.12/site-packages/puremagic/main.py", line 351, in magic_stream
    head, foot = _stream_details(stream)
                 ^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/…/.venv/lib/python3.12/site-packages/puremagic/main.py", line 229, in _stream_details
    stream.seek(-max_foot, os.SEEK_END)
OSError: [Errno 22] Invalid argument

not sure why, but maybe it's because it's trying to seek() to a position that's bigger than its size?

[NebularNerd]

I think this is related to my issue on #86

Converting your image to a .jpg works, converting it to a .webp produces the same errors. It seems to be an issue with certain formats, especially small file sizes. Doing a basic:

with open(r"icon-32.png", "rb") as file:
    print(file.read())

Shows the file can be read and displayed, so as you guessed it's like it keeps trying to read something not there.

JPG and WEBP.zip

EDIT
OK, this looks like an issue when calculating the footer, the .png is 198 bytes and the .webp is 280, while the .jpg is 815 bytes which is longer than the longest footer record of 516 bytes.

The culprit is an entry I added for MAC .dmg format in the footer which is 512 bytes, removing that (mostly) solves the problem. So, the footer calculator needs some better logic to handle short files. Time to break out the thinking grenades....

EDIT 2
I have a fix which should do the trick, PR incoming...

[cdgriffith]

Thanks for the fixes, addressed in 1.27!