#![feature(stdsimd)]
use std::simd::*;

fn ascii(input: &[u8]) -> bool {
    let len = input.len();
    let amax = u8x16::splat(0x80);
    let mut err = u8x16::splat(0);

    let mut i = 0;

    // Doing this in faster:
    // input.simd_iter().simd_reduce(u8s(0), u8s(0), |acc, v| acc | v).ge(u8s(0x80)).
    while i + 15 < len {
        let n = u8x16::load_aligned(&input[i..i+15]);
        err |= n;
        i += 16;
    }

    let err: m8x16 = err.ge(amax);

    let mut tail_has_char: u8 = 0;
    while i < len {
        tail_has_char |= input[i];
        i += 1;
    }

    err.all() || tail_has_char & 0x80 == 0
}

fn main() {
    let bs = b"Hello\x99";

    println!("{:?}", ascii(bs));
}