That function right there (and the vast majority of the rest of the file) is a straight decompiled version from Skype. You even use the register names and comment with addresses from the binary.
Having spent a lot of time reversing apps myself, this is a straight copyright violation. Your code is a directly derivative work from Skype.
At least 3/4 of those 4000 lines is directly copied from Skype, and that's just one file. I don't think that's small enough to not matter; anyway, if it really was so small, it should easily have been rewritten with original code.
No that's a simplistic approach. Both matter, for example one volume of the Encyclopedia Britannica is a very small portion of the overall work, but it cannot be freely copied. Likewise if you write a book a million pages long, copying entire chapters does not suddenly become ok.
It is my understanding that "the relevant copyrighted work" in the Encyclopedia Britannica example is likely to be the article rather than the entire encyclopedia.
Skype-open-source code here: https://github.com/skypeopensource/epycs
repo was closed because i host in download section deobfuscated skype5.5 binary, my fault.