If you use the naive algorithm at the top of the page but iterate over UTF-8 code points rather than bytes -- which is straightforward, BTW -- you will get some

If you use the naive algorithm at the top of the page but iterate over UTF-8 code points rather than bytes -- which is straightforward, BTW -- you will get some cleverness automatically in the compiler's implementation of the switch statement. I wrote a switch to handle the Unicode "is it space?" function, with the values from the table you linked, and compiled with "clang -Os". You know what it did? It generated a friggin' binary search tree! Some of the leaves were a sequence of straight-line comparisons, because that's more compact, but the higher levels were all a bunch of "if (c > 0x167F) { ... }" sort of code. At one point it subtracts 8192 from something and then compares with 12, and I think this is because the x86 instruction encoding is shorter and the compiler knows that the register won't be needed again along either of the code paths from that point. Compilers are amazing sometimes.