As a side note, the article and the simdjson paper don’t mention that it’s also possible to do an arbitrary set of bytes < 128 in two lookups (or one lookup and

As a side note, the article and the simdjson paper don’t mention that it’s also possible to do an arbitrary set of bytes < 128 in two lookups (or one lookup and one variable shift), by vectorizing !!(bitset[b >> 3] & oneshl[b & 7]), where bitset[i] has its jth bit set iff i*8+j is in the set, and oneshl[i] is 1<<i. (I don’t remember where I saw this first, unfortunately, a pull request to a Rust something or other.) If you’re on x86 and thus using PSHUFB for the lookup, making the first shift an arithmetic one will also see you reject bytes ≥ 128 automatically.