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
#![no_std]
#[cfg(test)]
#[macro_use]
extern crate std;
#[cfg(test)]
extern crate rand;
#[cfg(test)]
extern crate rand_xorshift;
#[cfg(test)]
#[macro_use]
extern crate quickcheck;
#[cfg(test)]
#[macro_use]
extern crate proptest;
#[cold]
fn ceil_div_slow(n: usize, d: usize) -> usize {
n / d + (if n % d > 0 { 1 } else { 0 })
}
#[inline(always)]
pub(crate) fn ceil_div(n: usize, d: usize) -> usize {
let nb = n.wrapping_add(d - 1);
if nb < n {
return ceil_div_slow(n, d);
};
nb / d
}
#[cold]
fn ceil_div_u64_slow(n: u64, d: u64) -> u64 {
n / d + (if n % d > 0 { 1 } else { 0 })
}
#[inline(always)]
pub(crate) fn ceil_div_u64(n: u64, d: u64) -> u64 {
let nb = n.wrapping_add(d - 1);
if nb < n {
return ceil_div_u64_slow(n, d);
};
nb / d
}
mod ones_or_zeros;
mod word;
mod bytes;
pub mod bits_ref;
mod with_offset;
pub mod index_raw;
#[cfg(test)]
mod tests {
use super::*;
use proptest::prelude::*;
#[test]
fn check_max_bits_in_bytes() {
assert!(<u64>::max_value() / 8 <= <usize>::max_value() as u64);
}
#[test]
fn test_ceil_div_examples() {
assert_eq!(0, ceil_div(0, 4));
assert_eq!(1, ceil_div(1, 4));
assert_eq!(1, ceil_div(4, 4));
assert_eq!(2, ceil_div(5, 4));
assert_eq!(2, ceil_div(6, 4));
assert_eq!(2, ceil_div(7, 4));
assert_eq!(2, ceil_div(8, 4));
assert_eq!(ceil_div_slow(0, 43), ceil_div(0, 43));
assert_eq!(ceil_div_slow(1, 43), ceil_div(1, 43));
assert_eq!(
ceil_div_slow(usize::max_value(), 43),
ceil_div(usize::max_value(), 43)
);
}
#[test]
fn test_ceil_div_u64_examples() {
assert_eq!(0, ceil_div_u64(0, 4));
assert_eq!(1, ceil_div_u64(1, 4));
assert_eq!(1, ceil_div_u64(4, 4));
assert_eq!(2, ceil_div_u64(5, 4));
assert_eq!(2, ceil_div_u64(6, 4));
assert_eq!(2, ceil_div_u64(7, 4));
assert_eq!(2, ceil_div_u64(8, 4));
assert_eq!(ceil_div_u64_slow(0, 43), ceil_div_u64(0, 43));
assert_eq!(ceil_div_u64_slow(1, 43), ceil_div_u64(1, 43));
assert_eq!(
ceil_div_u64_slow(u64::max_value(), 43),
ceil_div_u64(u64::max_value(), 43)
);
}
proptest! {
#[test]
fn test_ceil_div(x in any::<usize>(), d in 1..999999usize) {
prop_assert_eq!(ceil_div_slow(x, d), ceil_div(x, d));
}
#[test]
fn test_ceil_div_64(x in any::<u64>(), d in 1..999999u64) {
prop_assert_eq!(ceil_div_u64_slow(x, d), ceil_div_u64(x, d));
}
}
}