croaring/bitmap/
lazy.rs

1use crate::Bitmap;
2
3/// A handle to lazily perform multiple bitwise operations on a bitmap
4pub struct LazyBitmap<'a> {
5    bitmap: &'a mut Bitmap,
6}
7
8impl<'a> LazyBitmap<'a> {
9    /// Modifies the bitmap this lazy bitmap is associated with to be the union of the two bitmaps.
10    ///
11    /// # Arguments
12    /// * `other` - The other bitmap to union with.
13    /// * `force_bitsets` - Whether to force conversions to bitsets when modifying containers
14    #[inline]
15    #[doc(alias = "roaring_bitmap_lazy_or_inplace")]
16    pub fn or_inplace(&mut self, other: &Bitmap, force_bitsets: bool) -> &mut Self {
17        unsafe {
18            // Because we have a mutable borrow of the bitmap, `other` cannot be == our bitmap,
19            // so this is always safe
20            ffi::roaring_bitmap_lazy_or_inplace(
21                &mut self.bitmap.bitmap,
22                &other.bitmap,
23                force_bitsets,
24            );
25        }
26        self
27    }
28
29    /// Modifies the bitmap this lazy bitmap is associated with to be the xor of the two bitmaps.
30    #[inline]
31    #[doc(alias = "roaring_bitmap_lazy_xor_inplace")]
32    pub fn xor_inplace(&mut self, other: &Bitmap) -> &mut Self {
33        unsafe {
34            // Because we have a mutable borrow of the bitmap, `other` cannot be == our bitmap,
35            // so this is always safe
36            ffi::roaring_bitmap_lazy_xor_inplace(&mut self.bitmap.bitmap, &other.bitmap);
37        }
38        self
39    }
40}
41
42impl<'a> core::ops::BitOrAssign<&Bitmap> for LazyBitmap<'a> {
43    #[inline]
44    fn bitor_assign(&mut self, other: &Bitmap) {
45        self.or_inplace(other, false);
46    }
47}
48
49impl<'a> core::ops::BitXorAssign<&Bitmap> for LazyBitmap<'a> {
50    #[inline]
51    fn bitxor_assign(&mut self, other: &Bitmap) {
52        self.xor_inplace(other);
53    }
54}
55
56impl Bitmap {
57    /// Perform multiple bitwise operations on a bitmap.
58    ///
59    /// The passed closure will be passed a handle which can be used to perform bitwise operations on the bitmap lazily.
60    ///
61    /// The result will be equivalent to doing the same operations on this bitmap directly, but because of reduced
62    /// bookkeeping in between operations, it should be faster
63    ///
64    /// # Examples
65    ///
66    /// ```
67    /// use croaring::Bitmap;
68    ///
69    /// // Perform a series of bitwise operations on a bitmap:
70    /// let mut bitmap = Bitmap::of(&[99]);
71    /// let bitmaps_to_or = [Bitmap::of(&[1, 2, 5, 10]), Bitmap::of(&[1, 30, 100])];
72    /// let bitmaps_to_xor = [Bitmap::of(&[5]), Bitmap::of(&[1, 1000, 1001])];
73    ///
74    /// bitmap.lazy_batch(|lazy| {
75    ///     for b in &bitmaps_to_or {
76    ///         *lazy |= b;
77    ///     }
78    ///     for b in &bitmaps_to_xor {
79    ///         *lazy ^= b;
80    ///     }
81    /// });
82    /// let mut bitmap2 = Bitmap::of(&[99]);
83    /// for b in &bitmaps_to_or {
84    ///     bitmap2 |= b;
85    /// }
86    /// for b in &bitmaps_to_xor {
87    ///     bitmap2 ^= b;
88    /// }
89    /// assert_eq!(bitmap, bitmap2);
90    /// assert_eq!(bitmap.iter().collect::<Vec<_>>(), [2, 10, 30, 99, 100, 1000, 1001]);
91    /// ```
92    ///
93    /// The result the passed closure is returned from `lazy_batch`
94    ///
95    /// ```
96    /// use croaring::Bitmap;
97    ///
98    /// let mut bitmap = Bitmap::new();
99    /// let bitmaps_to_or = [Bitmap::of(&[1, 2, 5, 10]), Bitmap::of(&[1, 30, 100])];
100    /// let total_added = bitmap.lazy_batch(|lazy| {
101    ///     let mut total = 0;
102    ///     for b in &bitmaps_to_or {
103    ///         lazy.or_inplace(b, true);
104    ///         total += b.cardinality();
105    ///     }
106    ///     total
107    /// });
108    /// assert_eq!(total_added, 7);
109    #[doc(alias = "roaring_bitmap_repair_after_lazy")]
110    pub fn lazy_batch<F, O>(&mut self, f: F) -> O
111    where
112        F: FnOnce(&mut LazyBitmap<'_>) -> O,
113    {
114        let mut lazy_bitmap = LazyBitmap { bitmap: self };
115        let result = f(&mut lazy_bitmap);
116        unsafe {
117            ffi::roaring_bitmap_repair_after_lazy(&mut self.bitmap);
118        }
119        result
120    }
121}
croaring/bitmap/lazy.rs

croaring/bitmap/
lazy.rs
