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
pub struct Bitmap {
bits: Vec<u8>
}
impl Bitmap {
pub fn new(n: usize) -> Self {
let r = n % 64;
let len = if r==0 { n } else { n + 64-r };
let mut v = Vec::with_capacity(len);
for _ in 0 .. len {
v.push(0);
}
Bitmap { bits: v }
}
pub fn len(&self) -> usize {
self.bits.len()
}
pub fn is_set(&self, i: usize) -> bool {
let byte_offset = i / 8;
self.bits[byte_offset] & (1_u8 << ((i % 8) as u8)) > 0
}
pub fn set(&mut self, i: usize) {
let byte_offset = i / 8;
self.bits[byte_offset] = self.bits[byte_offset] | (1_u8 << ((i % 8) as u8));
}
pub fn clear(&mut self, i: usize) {
let byte_offset = i / 8;
self.bits[byte_offset] = self.bits[byte_offset] ^ (1_u8 << ((i % 8) as u8));
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_bitmap_length() {
assert_eq!(64, Bitmap::new(63).len());
assert_eq!(64, Bitmap::new(64).len());
assert_eq!(128, Bitmap::new(65).len());
}
#[test]
fn test_set_bit() {
let mut b = Bitmap::new(64);
assert_eq!(false, b.is_set(12));
b.set(12);
assert_eq!(true, b.is_set(12));
}
#[test]
fn test_clear_bit() {
let mut b = Bitmap::new(64);
assert_eq!(false, b.is_set(12));
b.set(12);
assert_eq!(true, b.is_set(12));
b.clear(12);
assert_eq!(false, b.is_set(12));
}
}