Software is subject to copyright. Yes you can implement the same APIs, but when you get into the visual presentation, things can get copyright related even if the code isn’t being ripped off.
If you decompile rather than clone, well then the code is copyrighted even if transformed into plausible source code.
The way I unterstand it, at least in European practice, the code itself is copyrighted, as in, the actual text, not the concept behing it. Decompiled source is not the same as original source, it goes through rounds of compiler optimisations and the process of reversing that includes a lot of guesswork. So, in practice, decompiling and working on the decompiled source was at least tolerated, probably because it would have been a grey area at worst.
Well, depends.
Software is subject to copyright. Yes you can implement the same APIs, but when you get into the visual presentation, things can get copyright related even if the code isn’t being ripped off.
If you decompile rather than clone, well then the code is copyrighted even if transformed into plausible source code.
Of course then there are patents…
The way I unterstand it, at least in European practice, the code itself is copyrighted, as in, the actual text, not the concept behing it. Decompiled source is not the same as original source, it goes through rounds of compiler optimisations and the process of reversing that includes a lot of guesswork. So, in practice, decompiling and working on the decompiled source was at least tolerated, probably because it would have been a grey area at worst.