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