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
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
|
use core::iter::*;
use super::*;
#[test]
fn test_repeat() {
let mut it = repeat(42);
assert_eq!(it.next(), Some(42));
assert_eq!(it.next(), Some(42));
assert_eq!(it.next(), Some(42));
assert_eq!(repeat(42).size_hint(), (usize::MAX, None));
}
#[test]
fn test_repeat_take() {
let mut it = repeat(42).take(3);
assert_eq!(it.next(), Some(42));
assert_eq!(it.next(), Some(42));
assert_eq!(it.next(), Some(42));
assert_eq!(it.next(), None);
is_trusted_len(repeat(42).take(3));
assert_eq!(repeat(42).take(3).size_hint(), (3, Some(3)));
assert_eq!(repeat(42).take(0).size_hint(), (0, Some(0)));
assert_eq!(repeat(42).take(usize::MAX).size_hint(), (usize::MAX, Some(usize::MAX)));
}
#[test]
fn test_repeat_take_collect() {
let v: Vec<_> = repeat(42).take(3).collect();
assert_eq!(v, vec![42, 42, 42]);
}
#[test]
fn test_repeat_with() {
#[derive(PartialEq, Debug)]
struct NotClone(usize);
let mut it = repeat_with(|| NotClone(42));
assert_eq!(it.next(), Some(NotClone(42)));
assert_eq!(it.next(), Some(NotClone(42)));
assert_eq!(it.next(), Some(NotClone(42)));
assert_eq!(repeat_with(|| NotClone(42)).size_hint(), (usize::MAX, None));
}
#[test]
fn test_repeat_with_take() {
let mut it = repeat_with(|| 42).take(3);
assert_eq!(it.next(), Some(42));
assert_eq!(it.next(), Some(42));
assert_eq!(it.next(), Some(42));
assert_eq!(it.next(), None);
is_trusted_len(repeat_with(|| 42).take(3));
assert_eq!(repeat_with(|| 42).take(3).size_hint(), (3, Some(3)));
assert_eq!(repeat_with(|| 42).take(0).size_hint(), (0, Some(0)));
assert_eq!(repeat_with(|| 42).take(usize::MAX).size_hint(), (usize::MAX, Some(usize::MAX)));
}
#[test]
fn test_repeat_with_take_collect() {
let mut curr = 1;
let v: Vec<_> = repeat_with(|| {
let tmp = curr;
curr *= 2;
tmp
})
.take(5)
.collect();
assert_eq!(v, vec![1, 2, 4, 8, 16]);
}
#[test]
fn test_successors() {
let mut powers_of_10 = successors(Some(1_u16), |n| n.checked_mul(10));
assert_eq!(powers_of_10.by_ref().collect::<Vec<_>>(), &[1, 10, 100, 1_000, 10_000]);
assert_eq!(powers_of_10.next(), None);
let mut empty = successors(None::<u32>, |_| unimplemented!());
assert_eq!(empty.next(), None);
assert_eq!(empty.next(), None);
}
#[test]
fn test_once() {
let mut it = once(42);
assert_eq!(it.next(), Some(42));
assert_eq!(it.next(), None);
}
#[test]
fn test_once_with() {
let count = Cell::new(0);
let mut it = once_with(|| {
count.set(count.get() + 1);
42
});
assert_eq!(count.get(), 0);
assert_eq!(it.next(), Some(42));
assert_eq!(count.get(), 1);
assert_eq!(it.next(), None);
assert_eq!(count.get(), 1);
assert_eq!(it.next(), None);
assert_eq!(count.get(), 1);
}
#[test]
fn test_empty() {
let mut it = empty::<i32>();
assert_eq!(it.next(), None);
}
#[test]
fn test_repeat_n_drop() {
#[derive(Clone, Debug)]
struct DropCounter<'a>(&'a Cell<usize>);
impl Drop for DropCounter<'_> {
fn drop(&mut self) {
self.0.set(self.0.get() + 1);
}
}
// `repeat_n(x, 0)` drops `x` immediately
let count = Cell::new(0);
let item = DropCounter(&count);
let mut it = repeat_n(item, 0);
assert_eq!(count.get(), 1);
assert!(it.next().is_none());
assert_eq!(count.get(), 1);
drop(it);
assert_eq!(count.get(), 1);
// Dropping the iterator needs to drop the item if it's non-empty
let count = Cell::new(0);
let item = DropCounter(&count);
let it = repeat_n(item, 3);
assert_eq!(count.get(), 0);
drop(it);
assert_eq!(count.get(), 1);
// Dropping the iterator doesn't drop the item if it was exhausted
let count = Cell::new(0);
let item = DropCounter(&count);
let mut it = repeat_n(item, 3);
assert_eq!(count.get(), 0);
let x0 = it.next().unwrap();
assert_eq!(count.get(), 0);
let x1 = it.next().unwrap();
assert_eq!(count.get(), 0);
let x2 = it.next().unwrap();
assert_eq!(count.get(), 0);
assert!(it.next().is_none());
assert_eq!(count.get(), 0);
assert!(it.next().is_none());
assert_eq!(count.get(), 0);
drop(it);
assert_eq!(count.get(), 0);
drop((x0, x1, x2));
assert_eq!(count.get(), 3);
}
#[test]
fn test_repeat_n_soundness() {
let x = std::iter::repeat_n(String::from("use after free"), 0);
println!("{x:?}");
pub struct PanicOnClone;
impl Clone for PanicOnClone {
fn clone(&self) -> Self {
unreachable!()
}
}
// `repeat_n` should drop the element immediately if `count` is zero.
// `Clone` should then not try to clone the element.
let x = std::iter::repeat_n(PanicOnClone, 0);
let _ = x.clone();
let mut y = std::iter::repeat_n(Box::new(0), 1);
let x = y.next().unwrap();
let _z = y;
assert_eq!(0, *x);
}
|
