1 use core::array::{self, FixedSizeArray, IntoIter};
2 use core::convert::TryFrom;
5 fn fixed_size_array() {
6 let mut array = [0; 64];
7 let mut zero_sized = [(); 64];
8 let mut empty_array = [0; 0];
9 let mut empty_zero_sized = [(); 0];
11 assert_eq!(FixedSizeArray::as_slice(&array).len(), 64);
12 assert_eq!(FixedSizeArray::as_slice(&zero_sized).len(), 64);
13 assert_eq!(FixedSizeArray::as_slice(&empty_array).len(), 0);
14 assert_eq!(FixedSizeArray::as_slice(&empty_zero_sized).len(), 0);
16 assert_eq!(FixedSizeArray::as_mut_slice(&mut array).len(), 64);
17 assert_eq!(FixedSizeArray::as_mut_slice(&mut zero_sized).len(), 64);
18 assert_eq!(FixedSizeArray::as_mut_slice(&mut empty_array).len(), 0);
19 assert_eq!(FixedSizeArray::as_mut_slice(&mut empty_zero_sized).len(), 0);
24 let value: String = "Hello World!".into();
25 let arr: &[String; 1] = array::from_ref(&value);
26 assert_eq!(&[value.clone()], arr);
31 let mut value: String = "Hello World".into();
32 let arr: &mut [String; 1] = array::from_mut(&mut value);
34 assert_eq!(&value, "Hello World!");
42 type Array = [u8; $N];
43 let array: Array = [0; $N];
44 let slice: &[u8] = &array[..];
46 let result = <&Array>::try_from(slice);
47 assert_eq!(&array, result.unwrap());
53 10 11 12 13 14 15 16 17 18 19
54 20 21 22 23 24 25 26 27 28 29
60 fn iterator_collect() {
61 let arr = [0, 1, 2, 5, 9];
62 let v: Vec<_> = IntoIter::new(arr.clone()).collect();
63 assert_eq!(&arr[..], &v[..]);
67 fn iterator_rev_collect() {
68 let arr = [0, 1, 2, 5, 9];
69 let v: Vec<_> = IntoIter::new(arr.clone()).rev().collect();
70 assert_eq!(&v[..], &[9, 5, 2, 1, 0]);
75 let v = [0, 1, 2, 3, 4];
77 assert_eq!(IntoIter::new(v.clone()).nth(i).unwrap(), v[i]);
79 assert_eq!(IntoIter::new(v.clone()).nth(v.len()), None);
81 let mut iter = IntoIter::new(v);
82 assert_eq!(iter.nth(2).unwrap(), v[2]);
83 assert_eq!(iter.nth(1).unwrap(), v[4]);
88 let v = [0, 1, 2, 3, 4];
89 assert_eq!(IntoIter::new(v).last().unwrap(), 4);
90 assert_eq!(IntoIter::new([0]).last().unwrap(), 0);
92 let mut it = IntoIter::new([0, 9, 2, 4]);
93 assert_eq!(it.next_back(), Some(4));
94 assert_eq!(it.last(), Some(2));
99 let mut it = IntoIter::new([0, 2, 4, 6, 8]);
100 assert_eq!(it.next(), Some(0));
101 assert_eq!(it.next_back(), Some(8));
102 let mut clone = it.clone();
103 assert_eq!(it.next_back(), Some(6));
104 assert_eq!(clone.next_back(), Some(6));
105 assert_eq!(it.next_back(), Some(4));
106 assert_eq!(clone.next_back(), Some(4));
107 assert_eq!(it.next(), Some(2));
108 assert_eq!(clone.next(), Some(2));
112 fn iterator_fused() {
113 let mut it = IntoIter::new([0, 9, 2]);
114 assert_eq!(it.next(), Some(0));
115 assert_eq!(it.next(), Some(9));
116 assert_eq!(it.next(), Some(2));
117 assert_eq!(it.next(), None);
118 assert_eq!(it.next(), None);
119 assert_eq!(it.next(), None);
120 assert_eq!(it.next(), None);
121 assert_eq!(it.next(), None);
126 let mut it = IntoIter::new([0, 1, 2, 5, 9]);
127 assert_eq!(it.size_hint(), (5, Some(5)));
128 assert_eq!(it.len(), 5);
129 assert_eq!(it.is_empty(), false);
131 assert_eq!(it.next(), Some(0));
132 assert_eq!(it.size_hint(), (4, Some(4)));
133 assert_eq!(it.len(), 4);
134 assert_eq!(it.is_empty(), false);
136 assert_eq!(it.next_back(), Some(9));
137 assert_eq!(it.size_hint(), (3, Some(3)));
138 assert_eq!(it.len(), 3);
139 assert_eq!(it.is_empty(), false);
142 let it = IntoIter::new([] as [String; 0]);
143 assert_eq!(it.size_hint(), (0, Some(0)));
144 assert_eq!(it.len(), 0);
145 assert_eq!(it.is_empty(), true);
149 fn iterator_count() {
150 let v = [0, 1, 2, 3, 4];
151 assert_eq!(IntoIter::new(v.clone()).count(), 5);
153 let mut iter2 = IntoIter::new(v);
156 assert_eq!(iter2.count(), 3);
160 fn iterator_flat_map() {
161 assert!((0..5).flat_map(|i| IntoIter::new([2 * i, 2 * i + 1])).eq(0..10));
165 fn iterator_debug() {
166 let arr = [0, 1, 2, 5, 9];
167 assert_eq!(format!("{:?}", IntoIter::new(arr)), "IntoIter([0, 1, 2, 5, 9])",);
171 fn iterator_drops() {
172 use core::cell::Cell;
174 // This test makes sure the correct number of elements are dropped. The `R`
175 // type is just a reference to a `Cell` that is incremented when an `R` is
179 struct Foo<'a>(&'a Cell<usize>);
181 impl Drop for Foo<'_> {
183 self.0.set(self.0.get() + 1);
187 fn five(i: &Cell<usize>) -> [Foo<'_>; 5] {
188 // This is somewhat verbose because `Foo` does not implement `Copy`
189 // since it implements `Drop`. Consequently, we cannot write
191 [Foo(i), Foo(i), Foo(i), Foo(i), Foo(i)]
194 // Simple: drop new iterator.
195 let i = Cell::new(0);
197 IntoIter::new(five(&i));
199 assert_eq!(i.get(), 5);
201 // Call `next()` once.
202 let i = Cell::new(0);
204 let mut iter = IntoIter::new(five(&i));
205 let _x = iter.next();
206 assert_eq!(i.get(), 0);
207 assert_eq!(iter.count(), 4);
208 assert_eq!(i.get(), 4);
210 assert_eq!(i.get(), 5);
212 // Check `clone` and calling `next`/`next_back`.
213 let i = Cell::new(0);
215 let mut iter = IntoIter::new(five(&i));
217 assert_eq!(i.get(), 1);
219 assert_eq!(i.get(), 2);
221 let mut clone = iter.clone();
222 assert_eq!(i.get(), 2);
225 assert_eq!(i.get(), 3);
228 assert_eq!(i.get(), 4);
230 assert_eq!(clone.count(), 2);
231 assert_eq!(i.get(), 6);
233 assert_eq!(i.get(), 8);
236 let i = Cell::new(0);
238 let mut iter = IntoIter::new(five(&i));
239 let _x = iter.nth(2);
240 assert_eq!(i.get(), 2);
241 let _y = iter.last();
242 assert_eq!(i.get(), 3);
244 assert_eq!(i.get(), 5);
246 // Check every element.
247 let i = Cell::new(0);
248 for (index, _x) in IntoIter::new(five(&i)).enumerate() {
249 assert_eq!(i.get(), index);
251 assert_eq!(i.get(), 5);
253 let i = Cell::new(0);
254 for (index, _x) in IntoIter::new(five(&i)).rev().enumerate() {
255 assert_eq!(i.get(), index);
257 assert_eq!(i.get(), 5);
260 // This test does not work on targets without panic=unwind support.
261 // To work around this problem, test is marked is should_panic, so it will
262 // be automagically skipped on unsuitable targets, such as
263 // wasm32-unknown-unkown.
265 // It means that we use panic for indicating success.
267 #[should_panic(expected = "test succeeded")]
268 fn array_default_impl_avoids_leaks_on_panic() {
269 use core::sync::atomic::{AtomicUsize, Ordering::Relaxed};
270 static COUNTER: AtomicUsize = AtomicUsize::new(0);
274 impl Default for Bomb {
275 fn default() -> Bomb {
276 if COUNTER.load(Relaxed) == 3 {
277 panic!("bomb limit exceeded");
280 COUNTER.fetch_add(1, Relaxed);
281 Bomb(COUNTER.load(Relaxed))
287 COUNTER.fetch_sub(1, Relaxed);
291 let res = std::panic::catch_unwind(|| <[Bomb; 5]>::default());
292 let panic_msg = match res {
293 Ok(_) => unreachable!(),
294 Err(p) => p.downcast::<&'static str>().unwrap(),
296 assert_eq!(*panic_msg, "bomb limit exceeded");
297 // check that all bombs are successfully dropped
298 assert_eq!(COUNTER.load(Relaxed), 0);
299 panic!("test succeeded")
303 fn empty_array_is_always_default() {
304 struct DoesNotImplDefault;
306 let _arr = <[DoesNotImplDefault; 0]>::default();
312 let b = a.map(|v| v + 1);
313 assert_eq!(b, [2, 3, 4]);
316 let b = a.map(|v| v as u64);
317 assert_eq!(b, [1, 2, 3]);
320 // See note on above test for why `should_panic` is used.
322 #[should_panic(expected = "test succeeded")]
323 fn array_map_drop_safety() {
324 use core::sync::atomic::AtomicUsize;
325 use core::sync::atomic::Ordering;
326 static DROPPED: AtomicUsize = AtomicUsize::new(0);
328 impl Drop for DropCounter {
330 DROPPED.fetch_add(1, Ordering::SeqCst);
334 let num_to_create = 5;
335 let success = std::panic::catch_unwind(|| {
339 assert!(nth < num_to_create);
344 assert!(success.is_err());
345 assert_eq!(DROPPED.load(Ordering::SeqCst), num_to_create);
346 panic!("test succeeded")
350 fn cell_allows_array_cycle() {
351 use core::cell::Cell;
355 a: [Cell<Option<&'a B<'a>>>; 2],
360 B { a: [Cell::new(None), Cell::new(None)] }
368 b1.a[0].set(Some(&b2));
369 b1.a[1].set(Some(&b3));
371 b2.a[0].set(Some(&b2));
372 b2.a[1].set(Some(&b3));
374 b3.a[0].set(Some(&b1));
375 b3.a[1].set(Some(&b2));