1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137

use std::collections::btree_map;
use std::iter::Peekable;

use RoaringBitmap;
use RoaringTreemap;

struct Pairs<'a>(Peekable<btree_map::Iter<'a, u32, RoaringBitmap>>,
                 Peekable<btree_map::Iter<'a, u32, RoaringBitmap>>);

impl RoaringTreemap {
    fn pairs<'a>(&'a self, other: &'a RoaringTreemap) -> Pairs<'a> {
        Pairs(self.map.iter().peekable(), other.map.iter().peekable())
    }

    /// Returns true if the set has no elements in common with other. This is equivalent to
    /// checking for an empty intersection.
    ///
    /// # Examples
    ///
    /// ```rust
    /// use roaring::RoaringTreemap;
    ///
    /// let mut rb1 = RoaringTreemap::new();
    /// let mut rb2 = RoaringTreemap::new();
    ///
    /// rb1.insert(1);
    ///
    /// assert_eq!(rb1.is_disjoint(&rb2), true);
    ///
    /// rb2.insert(1);
    ///
    /// assert_eq!(rb1.is_disjoint(&rb2), false);
    ///
    /// ```
    pub fn is_disjoint(&self, other: &Self) -> bool {
        self.pairs(other)
            .filter(|&(c1, c2)| c1.is_some() && c2.is_some())
            .all(|(c1, c2)| c1.unwrap().is_disjoint(c2.unwrap()))
    }

    /// Returns `true` if this set is a subset of `other`.
    ///
    /// # Examples
    ///
    /// ```rust
    /// use roaring::RoaringTreemap;
    ///
    /// let mut rb1 = RoaringTreemap::new();
    /// let mut rb2 = RoaringTreemap::new();
    ///
    /// rb1.insert(1);
    ///
    /// assert_eq!(rb1.is_subset(&rb2), false);
    ///
    /// rb2.insert(1);
    ///
    /// assert_eq!(rb1.is_subset(&rb2), true);
    ///
    /// rb1.insert(2);
    ///
    /// assert_eq!(rb1.is_subset(&rb2), false);
    /// ```
    pub fn is_subset(&self, other: &Self) -> bool {
        for pair in self.pairs(other) {
            match pair {
                (None, _) => (),
                (_, None) => {
                    return false;
                }
                (Some(c1), Some(c2)) => {
                    if !c1.is_subset(c2) {
                        return false;
                    }
                }
            }
        }
        true
    }

    /// Returns `true` if this set is a superset of `other`.
    ///
    /// # Examples
    ///
    /// ```rust
    /// use roaring::RoaringTreemap;
    ///
    /// let mut rb1 = RoaringTreemap::new();
    /// let mut rb2 = RoaringTreemap::new();
    ///
    /// rb1.insert(1);
    ///
    /// assert_eq!(rb2.is_superset(&rb1), false);
    ///
    /// rb2.insert(1);
    ///
    /// assert_eq!(rb2.is_superset(&rb1), true);
    ///
    /// rb1.insert(2);
    ///
    /// assert_eq!(rb2.is_superset(&rb1), false);
    /// ```
    pub fn is_superset(&self, other: &Self) -> bool {
        other.is_subset(self)
    }
}

impl<'a> Iterator for Pairs<'a> {
    type Item = (Option<&'a RoaringBitmap>, Option<&'a RoaringBitmap>);

    fn next(&mut self) -> Option<Self::Item> {
        enum Which {
            Left,
            Right,
            Both,
            None,
        };
        let which = match (self.0.peek(), self.1.peek()) {
            (None, None) => Which::None,
            (Some(_), None) => Which::Left,
            (None, Some(_)) => Which::Right,
            (Some(c1), Some(c2)) => {
                match (c1.0, c2.0) {
                    (key1, key2) if key1 == key2 => Which::Both,
                    (key1, key2) if key1 < key2 => Which::Left,
                    (key1, key2) if key1 > key2 => Which::Right,
                    (_, _) => unreachable!(),
                }
            }
        };
        match which {
            Which::Left => Some((self.0.next().map(|e| e.1), None)),
            Which::Right => Some((None, self.1.next().map(|e| e.1))),
            Which::Both => Some((self.0.next().map(|e| e.1), self.1.next().map(|e| e.1))),
            Which::None => None,
        }
    }
}