1use std::iter::FromIterator;
 2
 3pub fn simple_lowercase(c: char) -> char {
 4    c.to_lowercase().next().unwrap_or(c)
 5}
 6
 7#[derive(Copy, Clone, Debug, Default, PartialEq, Eq, Hash)]
 8pub struct CharBag(u64);
 9
10impl CharBag {
11    pub fn is_superset(self, other: CharBag) -> bool {
12        self.0 & other.0 == other.0
13    }
14
15    fn insert(&mut self, c: char) {
16        let c = simple_lowercase(c);
17        if c.is_ascii_lowercase() {
18            let mut count = self.0;
19            let idx = c as u8 - b'a';
20            count >>= idx * 2;
21            count = ((count << 1) | 1) & 3;
22            count <<= idx * 2;
23            self.0 |= count;
24        } else if c.is_ascii_digit() {
25            let idx = c as u8 - b'0';
26            self.0 |= 1 << (idx + 52);
27        } else if c == '-' {
28            self.0 |= 1 << 62;
29        }
30    }
31}
32
33impl Extend<char> for CharBag {
34    fn extend<T: IntoIterator<Item = char>>(&mut self, iter: T) {
35        for c in iter {
36            self.insert(c);
37        }
38    }
39}
40
41impl FromIterator<char> for CharBag {
42    fn from_iter<T: IntoIterator<Item = char>>(iter: T) -> Self {
43        let mut result = Self::default();
44        result.extend(iter);
45        result
46    }
47}
48
49impl From<&str> for CharBag {
50    fn from(s: &str) -> Self {
51        let mut bag = Self(0);
52        for c in s.chars() {
53            bag.insert(c);
54        }
55        bag
56    }
57}
58
59impl From<&[char]> for CharBag {
60    fn from(chars: &[char]) -> Self {
61        let mut bag = Self(0);
62        for c in chars {
63            bag.insert(*c);
64        }
65        bag
66    }
67}