That's idiomatic C code. You're right that it's not particularly readable if you aren't a C programmer, but if you came to a job interview and couldn't grok it immediately, I'd write "facility with C: marginal" in my notes.
Missed this back closer to when you posted it - but it's less that I don't understand what's going on, and more that this code is more likely to go wrong & be harder to debug than more descriptive code.
Just the other day, I was trying to identify what was being done by someone's "idiomatic" code, and had to keep three vertical screen's worth of data up just to follow what was happening. All that code was wrong, but because they were using pointers "idiomatically", it took a long time to find their off-by-one error.
Granted, they had gone about 4 levels further with pointers than the given example in the article, but the premise is similar.
