1 // Copyright 2014 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
12 use core::{i8, i16, isize};
17 let empty: [isize; 0] = [];
21 assert!(!xs.iter().lt(ys.iter()));
22 assert!(!xs.iter().le(ys.iter()));
23 assert!( xs.iter().gt(ys.iter()));
24 assert!( xs.iter().ge(ys.iter()));
26 assert!( ys.iter().lt(xs.iter()));
27 assert!( ys.iter().le(xs.iter()));
28 assert!(!ys.iter().gt(xs.iter()));
29 assert!(!ys.iter().ge(xs.iter()));
31 assert!( empty.iter().lt(xs.iter()));
32 assert!( empty.iter().le(xs.iter()));
33 assert!(!empty.iter().gt(xs.iter()));
34 assert!(!empty.iter().ge(xs.iter()));
37 let u = [1.0f64, 2.0];
38 let v = [0.0f64/0.0, 3.0];
40 assert!(!u.iter().lt(v.iter()));
41 assert!(!u.iter().le(v.iter()));
42 assert!(!u.iter().gt(v.iter()));
43 assert!(!u.iter().ge(v.iter()));
49 assert!(a.iter().lt(b.iter()) == (a[0] < b[0]));
50 assert!(a.iter().le(b.iter()) == (a[0] <= b[0]));
51 assert!(a.iter().gt(b.iter()) == (a[0] > b[0]));
52 assert!(a.iter().ge(b.iter()) == (a[0] >= b[0]));
54 assert!(c.iter().lt(b.iter()) == (c[0] < b[0]));
55 assert!(c.iter().le(b.iter()) == (c[0] <= b[0]));
56 assert!(c.iter().gt(b.iter()) == (c[0] > b[0]));
57 assert!(c.iter().ge(b.iter()) == (c[0] >= b[0]));
61 fn test_multi_iter() {
64 assert!(xs.iter().eq(ys.iter().rev()));
65 assert!(xs.iter().lt(xs.iter().skip(2)));
69 fn test_counter_from_iter() {
70 let it = (0..).step_by(5).take(10);
71 let xs: Vec<isize> = FromIterator::from_iter(it);
72 assert_eq!(xs, [0, 5, 10, 15, 20, 25, 30, 35, 40, 45]);
76 fn test_iterator_chain() {
77 let xs = [0, 1, 2, 3, 4, 5];
78 let ys = [30, 40, 50, 60];
79 let expected = [0, 1, 2, 3, 4, 5, 30, 40, 50, 60];
80 let it = xs.iter().chain(&ys);
83 assert_eq!(x, expected[i]);
86 assert_eq!(i, expected.len());
88 let ys = (30..).step_by(10).take(4);
89 let it = xs.iter().cloned().chain(ys);
92 assert_eq!(x, expected[i]);
95 assert_eq!(i, expected.len());
99 fn test_iterator_chain_nth() {
100 let xs = [0, 1, 2, 3, 4, 5];
101 let ys = [30, 40, 50, 60];
103 let expected = [0, 1, 2, 3, 4, 5, 30, 40, 50, 60];
104 for (i, x) in expected.iter().enumerate() {
105 assert_eq!(Some(x), xs.iter().chain(&ys).nth(i));
107 assert_eq!(zs.iter().chain(&xs).nth(0), Some(&0));
109 let mut it = xs.iter().chain(&zs);
110 assert_eq!(it.nth(5), Some(&5));
111 assert_eq!(it.next(), None);
115 fn test_iterator_chain_last() {
116 let xs = [0, 1, 2, 3, 4, 5];
117 let ys = [30, 40, 50, 60];
119 assert_eq!(xs.iter().chain(&ys).last(), Some(&60));
120 assert_eq!(zs.iter().chain(&ys).last(), Some(&60));
121 assert_eq!(ys.iter().chain(&zs).last(), Some(&60));
122 assert_eq!(zs.iter().chain(&zs).last(), None);
126 fn test_iterator_chain_count() {
127 let xs = [0, 1, 2, 3, 4, 5];
128 let ys = [30, 40, 50, 60];
130 assert_eq!(xs.iter().chain(&ys).count(), 10);
131 assert_eq!(zs.iter().chain(&ys).count(), 4);
135 fn test_iterator_chain_find() {
136 let xs = [0, 1, 2, 3, 4, 5];
137 let ys = [30, 40, 50, 60];
138 let mut iter = xs.iter().chain(&ys);
139 assert_eq!(iter.find(|&&i| i == 4), Some(&4));
140 assert_eq!(iter.next(), Some(&5));
141 assert_eq!(iter.find(|&&i| i == 40), Some(&40));
142 assert_eq!(iter.next(), Some(&50));
143 assert_eq!(iter.find(|&&i| i == 100), None);
144 assert_eq!(iter.next(), None);
148 fn test_iterator_step_by() {
150 let mut it = (0..).step_by(1).take(3);
151 assert_eq!(it.next(), Some(0));
152 assert_eq!(it.next(), Some(1));
153 assert_eq!(it.next(), Some(2));
154 assert_eq!(it.next(), None);
156 let mut it = (0..).step_by(3).take(4);
157 assert_eq!(it.next(), Some(0));
158 assert_eq!(it.next(), Some(3));
159 assert_eq!(it.next(), Some(6));
160 assert_eq!(it.next(), Some(9));
161 assert_eq!(it.next(), None);
166 fn test_iterator_step_by_zero() {
167 let mut it = (0..).step_by(0);
172 fn test_iterator_step_by_size_hint() {
173 struct StubSizeHint(usize, Option<usize>);
174 impl Iterator for StubSizeHint {
176 fn next(&mut self) -> Option<()> {
178 if let Some(ref mut upper) = self.1 {
183 fn size_hint(&self) -> (usize, Option<usize>) {
188 // The two checks in each case are needed because the logic
189 // is different before the first call to `next()`.
191 let mut it = StubSizeHint(10, Some(10)).step_by(1);
192 assert_eq!(it.size_hint(), (10, Some(10)));
194 assert_eq!(it.size_hint(), (9, Some(9)));
197 let mut it = StubSizeHint(10, Some(10)).step_by(3);
198 assert_eq!(it.size_hint(), (4, Some(4)));
200 assert_eq!(it.size_hint(), (3, Some(3)));
202 // larger base range, but not enough to get another element
203 let mut it = StubSizeHint(12, Some(12)).step_by(3);
204 assert_eq!(it.size_hint(), (4, Some(4)));
206 assert_eq!(it.size_hint(), (3, Some(3)));
208 // smaller base range, so fewer resulting elements
209 let mut it = StubSizeHint(9, Some(9)).step_by(3);
210 assert_eq!(it.size_hint(), (3, Some(3)));
212 assert_eq!(it.size_hint(), (2, Some(2)));
214 // infinite upper bound
215 let mut it = StubSizeHint(usize::MAX, None).step_by(1);
216 assert_eq!(it.size_hint(), (usize::MAX, None));
218 assert_eq!(it.size_hint(), (usize::MAX-1, None));
220 // still infinite with larger step
221 let mut it = StubSizeHint(7, None).step_by(3);
222 assert_eq!(it.size_hint(), (3, None));
224 assert_eq!(it.size_hint(), (2, None));
226 // propagates ExactSizeIterator
228 let it = a.iter().step_by(2);
229 assert_eq!(it.len(), 3);
231 // Cannot be TrustedLen as a step greater than one makes an iterator
232 // with (usize::MAX, None) no longer meet the safety requirements
233 trait TrustedLenCheck { fn test(self) -> bool; }
234 impl<T:Iterator> TrustedLenCheck for T {
235 default fn test(self) -> bool { false }
237 impl<T:TrustedLen> TrustedLenCheck for T {
238 fn test(self) -> bool { true }
240 assert!(TrustedLenCheck::test(a.iter()));
241 assert!(!TrustedLenCheck::test(a.iter().step_by(1)));
245 fn test_filter_map() {
246 let it = (0..).step_by(1).take(10)
247 .filter_map(|x| if x % 2 == 0 { Some(x*x) } else { None });
248 assert_eq!(it.collect::<Vec<usize>>(), [0*0, 2*2, 4*4, 6*6, 8*8]);
252 fn test_iterator_enumerate() {
253 let xs = [0, 1, 2, 3, 4, 5];
254 let it = xs.iter().enumerate();
261 fn test_iterator_enumerate_nth() {
262 let xs = [0, 1, 2, 3, 4, 5];
263 for (i, &x) in xs.iter().enumerate() {
267 let mut it = xs.iter().enumerate();
268 while let Some((i, &x)) = it.nth(0) {
272 let mut it = xs.iter().enumerate();
273 while let Some((i, &x)) = it.nth(1) {
277 let (i, &x) = xs.iter().enumerate().nth(3).unwrap();
283 fn test_iterator_enumerate_count() {
284 let xs = [0, 1, 2, 3, 4, 5];
285 assert_eq!(xs.iter().count(), 6);
289 fn test_iterator_filter_count() {
290 let xs = [0, 1, 2, 3, 4, 5, 6, 7, 8];
291 assert_eq!(xs.iter().filter(|&&x| x % 2 == 0).count(), 5);
295 fn test_iterator_peekable() {
296 let xs = vec![0, 1, 2, 3, 4, 5];
297 let mut it = xs.iter().cloned().peekable();
299 assert_eq!(it.len(), 6);
300 assert_eq!(it.peek().unwrap(), &0);
301 assert_eq!(it.len(), 6);
302 assert_eq!(it.next().unwrap(), 0);
303 assert_eq!(it.len(), 5);
304 assert_eq!(it.next().unwrap(), 1);
305 assert_eq!(it.len(), 4);
306 assert_eq!(it.next().unwrap(), 2);
307 assert_eq!(it.len(), 3);
308 assert_eq!(it.peek().unwrap(), &3);
309 assert_eq!(it.len(), 3);
310 assert_eq!(it.peek().unwrap(), &3);
311 assert_eq!(it.len(), 3);
312 assert_eq!(it.next().unwrap(), 3);
313 assert_eq!(it.len(), 2);
314 assert_eq!(it.next().unwrap(), 4);
315 assert_eq!(it.len(), 1);
316 assert_eq!(it.peek().unwrap(), &5);
317 assert_eq!(it.len(), 1);
318 assert_eq!(it.next().unwrap(), 5);
319 assert_eq!(it.len(), 0);
320 assert!(it.peek().is_none());
321 assert_eq!(it.len(), 0);
322 assert!(it.next().is_none());
323 assert_eq!(it.len(), 0);
327 fn test_iterator_peekable_count() {
328 let xs = [0, 1, 2, 3, 4, 5];
330 let zs: [i32; 0] = [];
332 assert_eq!(xs.iter().peekable().count(), 6);
334 let mut it = xs.iter().peekable();
335 assert_eq!(it.peek(), Some(&&0));
336 assert_eq!(it.count(), 6);
338 assert_eq!(ys.iter().peekable().count(), 1);
340 let mut it = ys.iter().peekable();
341 assert_eq!(it.peek(), Some(&&10));
342 assert_eq!(it.count(), 1);
344 assert_eq!(zs.iter().peekable().count(), 0);
346 let mut it = zs.iter().peekable();
347 assert_eq!(it.peek(), None);
352 fn test_iterator_peekable_nth() {
353 let xs = [0, 1, 2, 3, 4, 5];
354 let mut it = xs.iter().peekable();
356 assert_eq!(it.peek(), Some(&&0));
357 assert_eq!(it.nth(0), Some(&0));
358 assert_eq!(it.peek(), Some(&&1));
359 assert_eq!(it.nth(1), Some(&2));
360 assert_eq!(it.peek(), Some(&&3));
361 assert_eq!(it.nth(2), Some(&5));
362 assert_eq!(it.next(), None);
366 fn test_iterator_peekable_last() {
367 let xs = [0, 1, 2, 3, 4, 5];
370 let mut it = xs.iter().peekable();
371 assert_eq!(it.peek(), Some(&&0));
372 assert_eq!(it.last(), Some(&5));
374 let mut it = ys.iter().peekable();
375 assert_eq!(it.peek(), Some(&&0));
376 assert_eq!(it.last(), Some(&0));
378 let mut it = ys.iter().peekable();
379 assert_eq!(it.next(), Some(&0));
380 assert_eq!(it.peek(), None);
381 assert_eq!(it.last(), None);
384 /// This is an iterator that follows the Iterator contract,
385 /// but it is not fused. After having returned None once, it will start
386 /// producing elements if .next() is called again.
387 pub struct CycleIter<'a, T: 'a> {
392 pub fn cycle<T>(data: &[T]) -> CycleIter<T> {
399 impl<'a, T> Iterator for CycleIter<'a, T> {
401 fn next(&mut self) -> Option<Self::Item> {
402 let elt = self.data.get(self.index);
404 self.index %= 1 + self.data.len();
410 fn test_iterator_peekable_remember_peek_none_1() {
411 // Check that the loop using .peek() terminates
412 let data = [1, 2, 3];
413 let mut iter = cycle(&data).peekable();
416 while let Some(_) = iter.next() {
417 let is_the_last = iter.peek().is_none();
418 assert_eq!(is_the_last, n == data.len() - 1);
420 if n > data.len() { break; }
422 assert_eq!(n, data.len());
426 fn test_iterator_peekable_remember_peek_none_2() {
428 let mut iter = cycle(&data).peekable();
430 assert_eq!(iter.peek(), None);
431 assert_eq!(iter.last(), None);
435 fn test_iterator_peekable_remember_peek_none_3() {
437 let mut iter = cycle(&data).peekable();
439 assert_eq!(iter.nth(0), Some(&0));
441 let mut iter = cycle(&data).peekable();
443 assert_eq!(iter.peek(), None);
444 assert_eq!(iter.nth(0), None);
448 fn test_iterator_take_while() {
449 let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19];
450 let ys = [0, 1, 2, 3, 5, 13];
451 let it = xs.iter().take_while(|&x| *x < 15);
454 assert_eq!(*x, ys[i]);
457 assert_eq!(i, ys.len());
461 fn test_iterator_skip_while() {
462 let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19];
463 let ys = [15, 16, 17, 19];
464 let it = xs.iter().skip_while(|&x| *x < 15);
467 assert_eq!(*x, ys[i]);
470 assert_eq!(i, ys.len());
474 fn test_iterator_skip() {
475 let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19, 20, 30];
476 let ys = [13, 15, 16, 17, 19, 20, 30];
477 let mut it = xs.iter().skip(5);
479 while let Some(&x) = it.next() {
480 assert_eq!(x, ys[i]);
482 assert_eq!(it.len(), xs.len()-5-i);
484 assert_eq!(i, ys.len());
485 assert_eq!(it.len(), 0);
489 fn test_iterator_skip_doubleended() {
490 let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19, 20, 30];
491 let mut it = xs.iter().rev().skip(5);
492 assert_eq!(it.next(), Some(&15));
493 assert_eq!(it.by_ref().rev().next(), Some(&0));
494 assert_eq!(it.next(), Some(&13));
495 assert_eq!(it.by_ref().rev().next(), Some(&1));
496 assert_eq!(it.next(), Some(&5));
497 assert_eq!(it.by_ref().rev().next(), Some(&2));
498 assert_eq!(it.next(), Some(&3));
499 assert_eq!(it.next(), None);
500 let mut it = xs.iter().rev().skip(5).rev();
501 assert_eq!(it.next(), Some(&0));
502 assert_eq!(it.rev().next(), Some(&15));
503 let mut it_base = xs.iter();
505 let mut it = it_base.by_ref().skip(5).rev();
506 assert_eq!(it.next(), Some(&30));
507 assert_eq!(it.next(), Some(&20));
508 assert_eq!(it.next(), Some(&19));
509 assert_eq!(it.next(), Some(&17));
510 assert_eq!(it.next(), Some(&16));
511 assert_eq!(it.next(), Some(&15));
512 assert_eq!(it.next(), Some(&13));
513 assert_eq!(it.next(), None);
515 // make sure the skipped parts have not been consumed
516 assert_eq!(it_base.next(), Some(&0));
517 assert_eq!(it_base.next(), Some(&1));
518 assert_eq!(it_base.next(), Some(&2));
519 assert_eq!(it_base.next(), Some(&3));
520 assert_eq!(it_base.next(), Some(&5));
521 assert_eq!(it_base.next(), None);
522 let it = xs.iter().skip(5).rev();
523 assert_eq!(it.last(), Some(&13));
527 fn test_iterator_skip_nth() {
528 let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19, 20, 30];
530 let mut it = xs.iter().skip(0);
531 assert_eq!(it.nth(0), Some(&0));
532 assert_eq!(it.nth(1), Some(&2));
534 let mut it = xs.iter().skip(5);
535 assert_eq!(it.nth(0), Some(&13));
536 assert_eq!(it.nth(1), Some(&16));
538 let mut it = xs.iter().skip(12);
539 assert_eq!(it.nth(0), None);
544 fn test_iterator_skip_count() {
545 let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19, 20, 30];
547 assert_eq!(xs.iter().skip(0).count(), 12);
548 assert_eq!(xs.iter().skip(1).count(), 11);
549 assert_eq!(xs.iter().skip(11).count(), 1);
550 assert_eq!(xs.iter().skip(12).count(), 0);
551 assert_eq!(xs.iter().skip(13).count(), 0);
555 fn test_iterator_skip_last() {
556 let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19, 20, 30];
558 assert_eq!(xs.iter().skip(0).last(), Some(&30));
559 assert_eq!(xs.iter().skip(1).last(), Some(&30));
560 assert_eq!(xs.iter().skip(11).last(), Some(&30));
561 assert_eq!(xs.iter().skip(12).last(), None);
562 assert_eq!(xs.iter().skip(13).last(), None);
564 let mut it = xs.iter().skip(5);
565 assert_eq!(it.next(), Some(&13));
566 assert_eq!(it.last(), Some(&30));
570 fn test_iterator_take() {
571 let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19];
572 let ys = [0, 1, 2, 3, 5];
573 let mut it = xs.iter().take(5);
575 assert_eq!(it.len(), 5);
576 while let Some(&x) = it.next() {
577 assert_eq!(x, ys[i]);
579 assert_eq!(it.len(), 5-i);
581 assert_eq!(i, ys.len());
582 assert_eq!(it.len(), 0);
586 fn test_iterator_take_nth() {
587 let xs = [0, 1, 2, 4, 5];
588 let mut it = xs.iter();
590 let mut take = it.by_ref().take(3);
592 while let Some(&x) = take.nth(0) {
597 assert_eq!(it.nth(1), Some(&5));
598 assert_eq!(it.nth(0), None);
600 let xs = [0, 1, 2, 3, 4];
601 let mut it = xs.iter().take(7);
603 while let Some(&x) = it.nth(1) {
610 fn test_iterator_take_short() {
611 let xs = [0, 1, 2, 3];
612 let ys = [0, 1, 2, 3];
613 let mut it = xs.iter().take(5);
615 assert_eq!(it.len(), 4);
616 while let Some(&x) = it.next() {
617 assert_eq!(x, ys[i]);
619 assert_eq!(it.len(), 4-i);
621 assert_eq!(i, ys.len());
622 assert_eq!(it.len(), 0);
626 fn test_iterator_scan() {
627 // test the type inference
628 fn add(old: &mut isize, new: &usize) -> Option<f64> {
629 *old += *new as isize;
632 let xs = [0, 1, 2, 3, 4];
633 let ys = [0f64, 1.0, 3.0, 6.0, 10.0];
635 let it = xs.iter().scan(0, add);
638 assert_eq!(x, ys[i]);
641 assert_eq!(i, ys.len());
645 fn test_iterator_flat_map() {
647 let ys = [0, 1, 2, 3, 4, 5, 6, 7, 8];
648 let it = xs.iter().flat_map(|&x| (x..).step_by(1).take(3));
651 assert_eq!(x, ys[i]);
654 assert_eq!(i, ys.len());
659 let xs = [1, 2, 3, 4];
665 .collect::<Vec<usize>>();
667 assert_eq!(n, xs.len());
668 assert_eq!(&xs[..], &ys[..]);
674 let it = (0..).step_by(1).take(cycle_len).cycle();
675 assert_eq!(it.size_hint(), (usize::MAX, None));
676 for (i, x) in it.take(100).enumerate() {
677 assert_eq!(i % cycle_len, x);
680 let mut it = (0..).step_by(1).take(0).cycle();
681 assert_eq!(it.size_hint(), (0, Some(0)));
682 assert_eq!(it.next(), None);
686 fn test_iterator_nth() {
687 let v: &[_] = &[0, 1, 2, 3, 4];
688 for i in 0..v.len() {
689 assert_eq!(v.iter().nth(i).unwrap(), &v[i]);
691 assert_eq!(v.iter().nth(v.len()), None);
695 fn test_iterator_last() {
696 let v: &[_] = &[0, 1, 2, 3, 4];
697 assert_eq!(v.iter().last().unwrap(), &4);
698 assert_eq!(v[..1].iter().last().unwrap(), &0);
702 fn test_iterator_len() {
703 let v: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
704 assert_eq!(v[..4].iter().count(), 4);
705 assert_eq!(v[..10].iter().count(), 10);
706 assert_eq!(v[..0].iter().count(), 0);
710 fn test_iterator_sum() {
711 let v: &[i32] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
712 assert_eq!(v[..4].iter().cloned().sum::<i32>(), 6);
713 assert_eq!(v.iter().cloned().sum::<i32>(), 55);
714 assert_eq!(v[..0].iter().cloned().sum::<i32>(), 0);
718 fn test_iterator_sum_result() {
719 let v: &[Result<i32, ()>] = &[Ok(1), Ok(2), Ok(3), Ok(4)];
720 assert_eq!(v.iter().cloned().sum::<Result<i32, _>>(), Ok(10));
721 let v: &[Result<i32, ()>] = &[Ok(1), Err(()), Ok(3), Ok(4)];
722 assert_eq!(v.iter().cloned().sum::<Result<i32, _>>(), Err(()));
726 fn test_iterator_product() {
727 let v: &[i32] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
728 assert_eq!(v[..4].iter().cloned().product::<i32>(), 0);
729 assert_eq!(v[1..5].iter().cloned().product::<i32>(), 24);
730 assert_eq!(v[..0].iter().cloned().product::<i32>(), 1);
734 fn test_iterator_product_result() {
735 let v: &[Result<i32, ()>] = &[Ok(1), Ok(2), Ok(3), Ok(4)];
736 assert_eq!(v.iter().cloned().product::<Result<i32, _>>(), Ok(24));
737 let v: &[Result<i32, ()>] = &[Ok(1), Err(()), Ok(3), Ok(4)];
738 assert_eq!(v.iter().cloned().product::<Result<i32, _>>(), Err(()));
742 fn test_iterator_max() {
743 let v: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
744 assert_eq!(v[..4].iter().cloned().max(), Some(3));
745 assert_eq!(v.iter().cloned().max(), Some(10));
746 assert_eq!(v[..0].iter().cloned().max(), None);
750 fn test_iterator_min() {
751 let v: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
752 assert_eq!(v[..4].iter().cloned().min(), Some(0));
753 assert_eq!(v.iter().cloned().min(), Some(0));
754 assert_eq!(v[..0].iter().cloned().min(), None);
758 fn test_iterator_size_hint() {
759 let c = (0..).step_by(1);
760 let v: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9];
761 let v2 = &[10, 11, 12];
764 assert_eq!((0..).size_hint(), (usize::MAX, None));
765 assert_eq!(c.size_hint(), (usize::MAX, None));
766 assert_eq!(vi.clone().size_hint(), (10, Some(10)));
768 assert_eq!(c.clone().take(5).size_hint(), (5, Some(5)));
769 assert_eq!(c.clone().skip(5).size_hint().1, None);
770 assert_eq!(c.clone().take_while(|_| false).size_hint(), (0, None));
771 assert_eq!(c.clone().skip_while(|_| false).size_hint(), (0, None));
772 assert_eq!(c.clone().enumerate().size_hint(), (usize::MAX, None));
773 assert_eq!(c.clone().chain(vi.clone().cloned()).size_hint(), (usize::MAX, None));
774 assert_eq!(c.clone().zip(vi.clone()).size_hint(), (10, Some(10)));
775 assert_eq!(c.clone().scan(0, |_,_| Some(0)).size_hint(), (0, None));
776 assert_eq!(c.clone().filter(|_| false).size_hint(), (0, None));
777 assert_eq!(c.clone().map(|_| 0).size_hint(), (usize::MAX, None));
778 assert_eq!(c.filter_map(|_| Some(0)).size_hint(), (0, None));
780 assert_eq!(vi.clone().take(5).size_hint(), (5, Some(5)));
781 assert_eq!(vi.clone().take(12).size_hint(), (10, Some(10)));
782 assert_eq!(vi.clone().skip(3).size_hint(), (7, Some(7)));
783 assert_eq!(vi.clone().skip(12).size_hint(), (0, Some(0)));
784 assert_eq!(vi.clone().take_while(|_| false).size_hint(), (0, Some(10)));
785 assert_eq!(vi.clone().skip_while(|_| false).size_hint(), (0, Some(10)));
786 assert_eq!(vi.clone().enumerate().size_hint(), (10, Some(10)));
787 assert_eq!(vi.clone().chain(v2).size_hint(), (13, Some(13)));
788 assert_eq!(vi.clone().zip(v2).size_hint(), (3, Some(3)));
789 assert_eq!(vi.clone().scan(0, |_,_| Some(0)).size_hint(), (0, Some(10)));
790 assert_eq!(vi.clone().filter(|_| false).size_hint(), (0, Some(10)));
791 assert_eq!(vi.clone().map(|&i| i+1).size_hint(), (10, Some(10)));
792 assert_eq!(vi.filter_map(|_| Some(0)).size_hint(), (0, Some(10)));
797 let a = vec![1, 2, 3, 4, 5];
798 let b: Vec<isize> = a.iter().cloned().collect();
804 let v: Box<[isize]> = Box::new([1, 2, 3, 4, 5]);
805 assert!(v.iter().all(|&x| x < 10));
806 assert!(!v.iter().all(|&x| x % 2 == 0));
807 assert!(!v.iter().all(|&x| x > 100));
808 assert!(v[..0].iter().all(|_| panic!()));
813 let v: Box<[isize]> = Box::new([1, 2, 3, 4, 5]);
814 assert!(v.iter().any(|&x| x < 10));
815 assert!(v.iter().any(|&x| x % 2 == 0));
816 assert!(!v.iter().any(|&x| x > 100));
817 assert!(!v[..0].iter().any(|_| panic!()));
822 let v: &[isize] = &[1, 3, 9, 27, 103, 14, 11];
823 assert_eq!(*v.iter().find(|&&x| x & 1 == 0).unwrap(), 14);
824 assert_eq!(*v.iter().find(|&&x| x % 3 == 0).unwrap(), 3);
825 assert!(v.iter().find(|&&x| x % 12 == 0).is_none());
830 let v = &[1, 3, 9, 27, 103, 14, 11];
831 assert_eq!(v.iter().position(|x| *x & 1 == 0).unwrap(), 5);
832 assert_eq!(v.iter().position(|x| *x % 3 == 0).unwrap(), 1);
833 assert!(v.iter().position(|x| *x % 12 == 0).is_none());
838 let xs = &[1, 2, 2, 1, 5, 9, 0, 2];
839 assert_eq!(xs.iter().filter(|x| **x == 2).count(), 3);
840 assert_eq!(xs.iter().filter(|x| **x == 5).count(), 1);
841 assert_eq!(xs.iter().filter(|x| **x == 95).count(), 0);
845 fn test_max_by_key() {
846 let xs: &[isize] = &[-3, 0, 1, 5, -10];
847 assert_eq!(*xs.iter().max_by_key(|x| x.abs()).unwrap(), -10);
852 let xs: &[isize] = &[-3, 0, 1, 5, -10];
853 assert_eq!(*xs.iter().max_by(|x, y| x.abs().cmp(&y.abs())).unwrap(), -10);
857 fn test_min_by_key() {
858 let xs: &[isize] = &[-3, 0, 1, 5, -10];
859 assert_eq!(*xs.iter().min_by_key(|x| x.abs()).unwrap(), 0);
864 let xs: &[isize] = &[-3, 0, 1, 5, -10];
865 assert_eq!(*xs.iter().min_by(|x, y| x.abs().cmp(&y.abs())).unwrap(), 0);
871 // sum the first five values
872 let partial_sum = xs.by_ref().take(5).fold(0, |a, b| a + b);
873 assert_eq!(partial_sum, 10);
874 assert_eq!(xs.next(), Some(5));
879 let xs = [2, 4, 6, 8, 10, 12, 14, 16];
880 let mut it = xs.iter();
883 assert!(it.rev().cloned().collect::<Vec<isize>>() ==
884 vec![16, 14, 12, 10, 8, 6]);
889 let xs = [2, 4, 6, 8];
891 let mut it = xs.iter().cloned();
892 assert_eq!(it.len(), 4);
893 assert_eq!(it.next(), Some(2));
894 assert_eq!(it.len(), 3);
895 assert_eq!(it.next(), Some(4));
896 assert_eq!(it.len(), 2);
897 assert_eq!(it.next_back(), Some(8));
898 assert_eq!(it.len(), 1);
899 assert_eq!(it.next_back(), Some(6));
900 assert_eq!(it.len(), 0);
901 assert_eq!(it.next_back(), None);
905 fn test_double_ended_map() {
906 let xs = [1, 2, 3, 4, 5, 6];
907 let mut it = xs.iter().map(|&x| x * -1);
908 assert_eq!(it.next(), Some(-1));
909 assert_eq!(it.next(), Some(-2));
910 assert_eq!(it.next_back(), Some(-6));
911 assert_eq!(it.next_back(), Some(-5));
912 assert_eq!(it.next(), Some(-3));
913 assert_eq!(it.next_back(), Some(-4));
914 assert_eq!(it.next(), None);
918 fn test_double_ended_enumerate() {
919 let xs = [1, 2, 3, 4, 5, 6];
920 let mut it = xs.iter().cloned().enumerate();
921 assert_eq!(it.next(), Some((0, 1)));
922 assert_eq!(it.next(), Some((1, 2)));
923 assert_eq!(it.next_back(), Some((5, 6)));
924 assert_eq!(it.next_back(), Some((4, 5)));
925 assert_eq!(it.next_back(), Some((3, 4)));
926 assert_eq!(it.next_back(), Some((2, 3)));
927 assert_eq!(it.next(), None);
931 fn test_double_ended_zip() {
932 let xs = [1, 2, 3, 4, 5, 6];
933 let ys = [1, 2, 3, 7];
934 let a = xs.iter().cloned();
935 let b = ys.iter().cloned();
936 let mut it = a.zip(b);
937 assert_eq!(it.next(), Some((1, 1)));
938 assert_eq!(it.next(), Some((2, 2)));
939 assert_eq!(it.next_back(), Some((4, 7)));
940 assert_eq!(it.next_back(), Some((3, 3)));
941 assert_eq!(it.next(), None);
945 fn test_double_ended_filter() {
946 let xs = [1, 2, 3, 4, 5, 6];
947 let mut it = xs.iter().filter(|&x| *x & 1 == 0);
948 assert_eq!(it.next_back().unwrap(), &6);
949 assert_eq!(it.next_back().unwrap(), &4);
950 assert_eq!(it.next().unwrap(), &2);
951 assert_eq!(it.next_back(), None);
955 fn test_double_ended_filter_map() {
956 let xs = [1, 2, 3, 4, 5, 6];
957 let mut it = xs.iter().filter_map(|&x| if x & 1 == 0 { Some(x * 2) } else { None });
958 assert_eq!(it.next_back().unwrap(), 12);
959 assert_eq!(it.next_back().unwrap(), 8);
960 assert_eq!(it.next().unwrap(), 4);
961 assert_eq!(it.next_back(), None);
965 fn test_double_ended_chain() {
966 let xs = [1, 2, 3, 4, 5];
968 let mut it = xs.iter().chain(&ys).rev();
969 assert_eq!(it.next().unwrap(), &11);
970 assert_eq!(it.next().unwrap(), &9);
971 assert_eq!(it.next_back().unwrap(), &1);
972 assert_eq!(it.next_back().unwrap(), &2);
973 assert_eq!(it.next_back().unwrap(), &3);
974 assert_eq!(it.next_back().unwrap(), &4);
975 assert_eq!(it.next_back().unwrap(), &5);
976 assert_eq!(it.next_back().unwrap(), &7);
977 assert_eq!(it.next_back(), None);
980 // test that .chain() is well behaved with an unfused iterator
981 struct CrazyIterator(bool);
982 impl CrazyIterator { fn new() -> CrazyIterator { CrazyIterator(false) } }
983 impl Iterator for CrazyIterator {
985 fn next(&mut self) -> Option<i32> {
986 if self.0 { Some(99) } else { self.0 = true; None }
990 impl DoubleEndedIterator for CrazyIterator {
991 fn next_back(&mut self) -> Option<i32> {
996 assert_eq!(CrazyIterator::new().chain(0..10).rev().last(), Some(0));
997 assert!((0..10).chain(CrazyIterator::new()).rev().any(|i| i == 0));
1001 fn test_rposition() {
1002 fn f(xy: &(isize, char)) -> bool { let (_x, y) = *xy; y == 'b' }
1003 fn g(xy: &(isize, char)) -> bool { let (_x, y) = *xy; y == 'd' }
1004 let v = [(0, 'a'), (1, 'b'), (2, 'c'), (3, 'b')];
1006 assert_eq!(v.iter().rposition(f), Some(3));
1007 assert!(v.iter().rposition(g).is_none());
1012 fn test_rposition_panic() {
1013 let v: [(Box<_>, Box<_>); 4] =
1014 [(box 0, box 0), (box 0, box 0),
1015 (box 0, box 0), (box 0, box 0)];
1017 v.iter().rposition(|_elt| {
1028 fn test_double_ended_flat_map() {
1031 let mut it = u.iter().flat_map(|x| &v[*x..v.len()]);
1032 assert_eq!(it.next_back().unwrap(), &8);
1033 assert_eq!(it.next().unwrap(), &5);
1034 assert_eq!(it.next_back().unwrap(), &7);
1035 assert_eq!(it.next_back().unwrap(), &6);
1036 assert_eq!(it.next_back().unwrap(), &8);
1037 assert_eq!(it.next().unwrap(), &6);
1038 assert_eq!(it.next_back().unwrap(), &7);
1039 assert_eq!(it.next_back(), None);
1040 assert_eq!(it.next(), None);
1041 assert_eq!(it.next_back(), None);
1045 fn test_double_ended_range() {
1046 assert_eq!((11..14).rev().collect::<Vec<_>>(), [13, 12, 11]);
1047 for _ in (10..0).rev() {
1048 panic!("unreachable");
1051 assert_eq!((11..14).rev().collect::<Vec<_>>(), [13, 12, 11]);
1052 for _ in (10..0).rev() {
1053 panic!("unreachable");
1059 assert_eq!((0..5).collect::<Vec<_>>(), [0, 1, 2, 3, 4]);
1060 assert_eq!((-10..-1).collect::<Vec<_>>(), [-10, -9, -8, -7, -6, -5, -4, -3, -2]);
1061 assert_eq!((0..5).rev().collect::<Vec<_>>(), [4, 3, 2, 1, 0]);
1062 assert_eq!((200..-5).count(), 0);
1063 assert_eq!((200..-5).rev().count(), 0);
1064 assert_eq!((200..200).count(), 0);
1065 assert_eq!((200..200).rev().count(), 0);
1067 assert_eq!((0..100).size_hint(), (100, Some(100)));
1068 // this test is only meaningful when sizeof usize < sizeof u64
1069 assert_eq!((usize::MAX - 1..usize::MAX).size_hint(), (1, Some(1)));
1070 assert_eq!((-10..-1).size_hint(), (9, Some(9)));
1071 assert_eq!((-1..-10).size_hint(), (0, Some(0)));
1073 assert_eq!((-70..58).size_hint(), (128, Some(128)));
1074 assert_eq!((-128..127).size_hint(), (255, Some(255)));
1075 assert_eq!((-2..isize::MAX).size_hint(),
1076 (isize::MAX as usize + 2, Some(isize::MAX as usize + 2)));
1080 fn test_range_inclusive_exhaustion() {
1081 let mut r = 10...10;
1082 assert_eq!(r.next(), Some(10));
1083 assert_eq!(r, 1...0);
1085 let mut r = 10...10;
1086 assert_eq!(r.next_back(), Some(10));
1087 assert_eq!(r, 1...0);
1089 let mut r = 10...12;
1090 assert_eq!(r.nth(2), Some(12));
1091 assert_eq!(r, 1...0);
1093 let mut r = 10...12;
1094 assert_eq!(r.nth(5), None);
1095 assert_eq!(r, 1...0);
1100 fn test_range_nth() {
1101 assert_eq!((10..15).nth(0), Some(10));
1102 assert_eq!((10..15).nth(1), Some(11));
1103 assert_eq!((10..15).nth(4), Some(14));
1104 assert_eq!((10..15).nth(5), None);
1107 assert_eq!(r.nth(2), Some(12));
1108 assert_eq!(r, 13..20);
1109 assert_eq!(r.nth(2), Some(15));
1110 assert_eq!(r, 16..20);
1111 assert_eq!(r.nth(10), None);
1112 assert_eq!(r, 20..20);
1116 fn test_range_from_nth() {
1117 assert_eq!((10..).nth(0), Some(10));
1118 assert_eq!((10..).nth(1), Some(11));
1119 assert_eq!((10..).nth(4), Some(14));
1122 assert_eq!(r.nth(2), Some(12));
1123 assert_eq!(r, 13..);
1124 assert_eq!(r.nth(2), Some(15));
1125 assert_eq!(r, 16..);
1126 assert_eq!(r.nth(10), Some(26));
1127 assert_eq!(r, 27..);
1131 fn test_range_inclusive_nth() {
1132 assert_eq!((10...15).nth(0), Some(10));
1133 assert_eq!((10...15).nth(1), Some(11));
1134 assert_eq!((10...15).nth(5), Some(15));
1135 assert_eq!((10...15).nth(6), None);
1137 let mut r = 10_u8...20;
1138 assert_eq!(r.nth(2), Some(12));
1139 assert_eq!(r, 13...20);
1140 assert_eq!(r.nth(2), Some(15));
1141 assert_eq!(r, 16...20);
1142 assert_eq!(r.is_empty(), false);
1143 assert_eq!(r.nth(10), None);
1144 assert_eq!(r.is_empty(), true);
1145 assert_eq!(r, 1...0); // We may not want to document/promise this detail
1149 fn test_range_step() {
1150 #![allow(deprecated)]
1152 assert_eq!((0..20).step_by(5).collect::<Vec<isize>>(), [0, 5, 10, 15]);
1153 assert_eq!((1..21).rev().step_by(5).collect::<Vec<isize>>(), [20, 15, 10, 5]);
1154 assert_eq!((1..21).rev().step_by(6).collect::<Vec<isize>>(), [20, 14, 8, 2]);
1155 assert_eq!((200..255).step_by(50).collect::<Vec<u8>>(), [200, 250]);
1156 assert_eq!((200..-5).step_by(1).collect::<Vec<isize>>(), []);
1157 assert_eq!((200..200).step_by(1).collect::<Vec<isize>>(), []);
1159 assert_eq!((0..20).step_by(1).size_hint(), (20, Some(20)));
1160 assert_eq!((0..20).step_by(21).size_hint(), (1, Some(1)));
1161 assert_eq!((0..20).step_by(5).size_hint(), (4, Some(4)));
1162 assert_eq!((1..21).rev().step_by(5).size_hint(), (4, Some(4)));
1163 assert_eq!((1..21).rev().step_by(6).size_hint(), (4, Some(4)));
1164 assert_eq!((20..-5).step_by(1).size_hint(), (0, Some(0)));
1165 assert_eq!((20..20).step_by(1).size_hint(), (0, Some(0)));
1166 assert_eq!((i8::MIN..i8::MAX).step_by(-(i8::MIN as i32) as usize).size_hint(), (2, Some(2)));
1167 assert_eq!((i16::MIN..i16::MAX).step_by(i16::MAX as usize).size_hint(), (3, Some(3)));
1168 assert_eq!((isize::MIN..isize::MAX).step_by(1).size_hint(), (usize::MAX, Some(usize::MAX)));
1173 let mut it = repeat(42);
1174 assert_eq!(it.next(), Some(42));
1175 assert_eq!(it.next(), Some(42));
1176 assert_eq!(it.next(), Some(42));
1182 assert_eq!(it.len(), 3);
1183 assert_eq!(it.next(), Some(0));
1184 assert_eq!(it.len(), 2);
1185 assert_eq!(it.next(), Some(1));
1186 assert_eq!(it.len(), 1);
1187 assert_eq!(it.next(), Some(2));
1188 assert_eq!(it.len(), 0);
1189 assert_eq!(it.next(), None);
1190 assert_eq!(it.len(), 0);
1191 assert_eq!(it.next(), None);
1192 assert_eq!(it.len(), 0);
1193 assert_eq!(it.next(), None);
1194 assert_eq!(it.len(), 0);
1198 fn test_fuse_nth() {
1200 let mut it = xs.iter();
1202 assert_eq!(it.len(), 3);
1203 assert_eq!(it.nth(2), Some(&2));
1204 assert_eq!(it.len(), 0);
1205 assert_eq!(it.nth(2), None);
1206 assert_eq!(it.len(), 0);
1210 fn test_fuse_last() {
1214 assert_eq!(it.len(), 3);
1215 assert_eq!(it.last(), Some(&2));
1219 fn test_fuse_count() {
1223 assert_eq!(it.len(), 3);
1224 assert_eq!(it.count(), 3);
1225 // Can't check len now because count consumes.
1230 let mut it = once(42);
1231 assert_eq!(it.next(), Some(42));
1232 assert_eq!(it.next(), None);
1237 let mut it = empty::<i32>();
1238 assert_eq!(it.next(), None);
1242 fn test_chain_fold() {
1246 let mut iter = xs.iter().chain(&ys);
1248 let mut result = Vec::new();
1249 iter.fold((), |(), &elt| result.push(elt));
1250 assert_eq!(&[2, 3, 1, 2, 0], &result[..]);
1254 fn test_step_replace_unsigned() {
1256 let y = x.replace_zero();
1261 let y = x.replace_one();
1267 fn test_step_replace_signed() {
1269 let y = x.replace_zero();
1274 let y = x.replace_one();
1280 fn test_step_replace_no_between() {
1282 let y = x.replace_zero();
1287 let y = x.replace_one();