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pub struct SmallCharSet {
pub bits: u64,
}
impl SmallCharSet {
#[inline]
fn contains(&self, n: u8) -> bool {
0 != (self.bits & (1 << (n as usize)))
}
pub fn nonmember_prefix_len(&self, buf: &str) -> u32 {
let mut n = 0;
for b in buf.bytes() {
if b >= 64 || !self.contains(b) {
n += 1;
} else {
break;
}
}
n
}
}
#[cfg(test)]
mod test {
use std::iter::repeat;
#[test]
fn nonmember_prefix() {
for &c in ['&', '\0'].iter() {
for x in 0 .. 48u32 {
for y in 0 .. 48u32 {
let mut s = repeat("x").take(x as usize).collect::<String>();
s.push(c);
s.push_str(&repeat("x").take(y as usize).collect::<String>());
let set = small_char_set!('&' '\0');
assert_eq!(x, set.nonmember_prefix_len(&s));
}
}
}
}
}