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
|
#[cfg(feature = "arbitrary")]
use arbitrary::Arbitrary;
use std::num::NonZeroUsize;
/// A non-empty list which statically guarantees certain operations
/// cannot return zero, using [`std::num::NonZeroUsize`].
///
/// *Experimental*
///
#[repr(transparent)]
#[cfg_attr(feature = "arbitrary", derive(Arbitrary))]
#[derive(Clone, Debug, PartialEq, Eq, Hash, PartialOrd, Ord)]
pub struct NonEmpty<T>(super::NonEmpty<T>);
impl<T> NonEmpty<T> {
/// Get the length of the list.
pub fn len(&self) -> NonZeroUsize {
unsafe { NonZeroUsize::new_unchecked(self.0.tail.len() + 1) }
}
/// Get the capacity of the list.
pub fn capacity(&self) -> NonZeroUsize {
unsafe { NonZeroUsize::new_unchecked(self.0.tail.capacity() + 1) }
}
/// Truncate the list to a certain size.
pub fn truncate(&mut self, len: NonZeroUsize) {
self.tail.truncate(usize::from(len) - 1);
}
}
impl<T> From<super::NonEmpty<T>> for NonEmpty<T> {
fn from(other: super::NonEmpty<T>) -> NonEmpty<T> {
NonEmpty(other)
}
}
impl<T> std::ops::Deref for NonEmpty<T> {
type Target = super::NonEmpty<T>;
fn deref(&self) -> &Self::Target {
&self.0
}
}
impl<T> std::ops::DerefMut for NonEmpty<T> {
fn deref_mut(&mut self) -> &mut Self::Target {
&mut self.0
}
}
#[cfg(test)]
mod tests {
use crate::nonzero;
use crate::NonEmpty;
use std::convert::TryInto;
#[test]
fn test_nonzero() {
let nonempty: nonzero::NonEmpty<_> = NonEmpty::from((0, vec![1, 2, 3])).into();
assert_eq!(nonempty.len(), 4.try_into().unwrap());
assert_eq!(nonempty.capacity(), 4.try_into().unwrap());
}
#[cfg(feature = "arbitrary")]
mod arbitrary {
use crate::nonzero;
use arbitrary::{Arbitrary, Unstructured};
use std::convert::TryInto;
#[test]
fn test_nonzero_arbitrary_empty_tail() -> arbitrary::Result<()> {
let mut u = Unstructured::new(&[1, 2, 3, 4]);
let nonempty: nonzero::NonEmpty<_> = nonzero::NonEmpty::<i32>::arbitrary(&mut u)?;
assert_eq!(nonempty.len(), 1.try_into().unwrap());
assert_eq!(nonempty.capacity(), 1.try_into().unwrap());
Ok(())
}
#[test]
fn test_nonzero_arbitrary_with_tail() -> arbitrary::Result<()> {
let mut u = Unstructured::new(&[1, 2, 3, 4, 5, 6, 7, 8]);
let nonempty: nonzero::NonEmpty<_> = nonzero::NonEmpty::<i32>::arbitrary(&mut u)?;
assert_eq!(nonempty.len(), 2.try_into().unwrap());
assert_eq!(nonempty.capacity(), 5.try_into().unwrap());
Ok(())
}
}
}
|
