libhpcalcs: portable (Windows / MacOS X / Linux) connectivity kit library

[debrouxl]

Hmm. This logging output shows that the data received by libhpcalcs is pure garbage:
* the "unknown marker at beginning of image" message;
* the last packet is entirely made of 0x00, which never happens with a valid screenshot;
* last but not least, the maximum expected size for a type 8 screenshot (320x240x16 bpp) is 153600 uncompressed bytes, i.e. quite a bit less than the 199395 bytes declared by the packet. I'm not aware that zlib compression has the property of blowing up the size of non-compressible output by as much as 20+%.
Type 8 screenshots are typically 18000-20000 bytes for a screenshot of the Apps screen, fewer bytes for other more homogeneous screens (typically 6000-7000 for an empty Home / Function screen).

Granted, some of the cleanups which I pushed this morning did change some code paths exercised by attempting to obtain a screenshot:
* "Extract function for computing the size of a Prime virtual packet, export it from the library." - but it can't be that one, the change is a no-op;
* "Make the "data" argument of cable receive functions a double pointer; use that to optimize several functions in prime_cmd." - both the rpkt and the link_prime_hid layers were changed.
However... the exact same relevant code paths were exercised when you received a file, which was a success !

To sum up: I don't know why this happens...

By chance, does the problem go away after simply rebooting your calculator ?