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
use std::u64;
#[derive(Debug, Default, Clone)]
pub struct SizeHint {
lower: u64,
upper: Option<u64>,
}
impl SizeHint {
#[inline]
pub fn new() -> SizeHint {
SizeHint::default()
}
#[inline]
pub fn with_exact(value: u64) -> SizeHint {
SizeHint {
lower: value,
upper: Some(value),
}
}
#[inline]
pub fn lower(&self) -> u64 {
self.lower
}
#[inline]
pub fn set_lower(&mut self, value: u64) {
assert!(value <= self.upper.unwrap_or(u64::MAX));
self.lower = value;
}
#[inline]
pub fn upper(&self) -> Option<u64> {
self.upper
}
#[inline]
pub fn set_upper(&mut self, value: u64) {
assert!(value >= self.lower, "`value` is less than than `lower`");
self.upper = Some(value);
}
#[inline]
pub fn exact(&self) -> Option<u64> {
if Some(self.lower) == self.upper {
self.upper
} else {
None
}
}
#[inline]
pub fn set_exact(&mut self, value: u64) {
self.lower = value;
self.upper = Some(value);
}
}