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};
20 let empty: [isize; 0] = [];
24 assert!(!xs.iter().lt(ys.iter()));
25 assert!(!xs.iter().le(ys.iter()));
26 assert!( xs.iter().gt(ys.iter()));
27 assert!( xs.iter().ge(ys.iter()));
29 assert!( ys.iter().lt(xs.iter()));
30 assert!( ys.iter().le(xs.iter()));
31 assert!(!ys.iter().gt(xs.iter()));
32 assert!(!ys.iter().ge(xs.iter()));
34 assert!( empty.iter().lt(xs.iter()));
35 assert!( empty.iter().le(xs.iter()));
36 assert!(!empty.iter().gt(xs.iter()));
37 assert!(!empty.iter().ge(xs.iter()));
40 let u = [1.0f64, 2.0];
41 let v = [0.0f64/0.0, 3.0];
43 assert!(!u.iter().lt(v.iter()));
44 assert!(!u.iter().le(v.iter()));
45 assert!(!u.iter().gt(v.iter()));
46 assert!(!u.iter().ge(v.iter()));
52 assert!(a.iter().lt(b.iter()) == (a[0] < b[0]));
53 assert!(a.iter().le(b.iter()) == (a[0] <= b[0]));
54 assert!(a.iter().gt(b.iter()) == (a[0] > b[0]));
55 assert!(a.iter().ge(b.iter()) == (a[0] >= b[0]));
57 assert!(c.iter().lt(b.iter()) == (c[0] < b[0]));
58 assert!(c.iter().le(b.iter()) == (c[0] <= b[0]));
59 assert!(c.iter().gt(b.iter()) == (c[0] > b[0]));
60 assert!(c.iter().ge(b.iter()) == (c[0] >= b[0]));
64 fn test_multi_iter() {
67 assert!(xs.iter().eq(ys.iter().rev()));
68 assert!(xs.iter().lt(xs.iter().skip(2)));
72 fn test_counter_from_iter() {
73 let it = (0..).step_by(5).take(10);
74 let xs: Vec<isize> = FromIterator::from_iter(it);
75 assert_eq!(xs, [0, 5, 10, 15, 20, 25, 30, 35, 40, 45]);
79 fn test_iterator_chain() {
80 let xs = [0, 1, 2, 3, 4, 5];
81 let ys = [30, 40, 50, 60];
82 let expected = [0, 1, 2, 3, 4, 5, 30, 40, 50, 60];
83 let it = xs.iter().chain(&ys);
86 assert_eq!(x, expected[i]);
89 assert_eq!(i, expected.len());
91 let ys = (30..).step_by(10).take(4);
92 let it = xs.iter().cloned().chain(ys);
95 assert_eq!(x, expected[i]);
98 assert_eq!(i, expected.len());
102 fn test_iterator_chain_nth() {
103 let xs = [0, 1, 2, 3, 4, 5];
104 let ys = [30, 40, 50, 60];
106 let expected = [0, 1, 2, 3, 4, 5, 30, 40, 50, 60];
107 for (i, x) in expected.iter().enumerate() {
108 assert_eq!(Some(x), xs.iter().chain(&ys).nth(i));
110 assert_eq!(zs.iter().chain(&xs).nth(0), Some(&0));
112 let mut it = xs.iter().chain(&zs);
113 assert_eq!(it.nth(5), Some(&5));
114 assert_eq!(it.next(), None);
118 fn test_iterator_chain_last() {
119 let xs = [0, 1, 2, 3, 4, 5];
120 let ys = [30, 40, 50, 60];
122 assert_eq!(xs.iter().chain(&ys).last(), Some(&60));
123 assert_eq!(zs.iter().chain(&ys).last(), Some(&60));
124 assert_eq!(ys.iter().chain(&zs).last(), Some(&60));
125 assert_eq!(zs.iter().chain(&zs).last(), None);
129 fn test_iterator_chain_count() {
130 let xs = [0, 1, 2, 3, 4, 5];
131 let ys = [30, 40, 50, 60];
133 assert_eq!(xs.iter().chain(&ys).count(), 10);
134 assert_eq!(zs.iter().chain(&ys).count(), 4);
138 fn test_iterator_chain_find() {
139 let xs = [0, 1, 2, 3, 4, 5];
140 let ys = [30, 40, 50, 60];
141 let mut iter = xs.iter().chain(&ys);
142 assert_eq!(iter.find(|&&i| i == 4), Some(&4));
143 assert_eq!(iter.next(), Some(&5));
144 assert_eq!(iter.find(|&&i| i == 40), Some(&40));
145 assert_eq!(iter.next(), Some(&50));
146 assert_eq!(iter.find(|&&i| i == 100), None);
147 assert_eq!(iter.next(), None);
151 fn test_filter_map() {
152 let it = (0..).step_by(1).take(10)
153 .filter_map(|x| if x % 2 == 0 { Some(x*x) } else { None });
154 assert_eq!(it.collect::<Vec<usize>>(), [0*0, 2*2, 4*4, 6*6, 8*8]);
158 fn test_iterator_enumerate() {
159 let xs = [0, 1, 2, 3, 4, 5];
160 let it = xs.iter().enumerate();
167 fn test_iterator_enumerate_nth() {
168 let xs = [0, 1, 2, 3, 4, 5];
169 for (i, &x) in xs.iter().enumerate() {
173 let mut it = xs.iter().enumerate();
174 while let Some((i, &x)) = it.nth(0) {
178 let mut it = xs.iter().enumerate();
179 while let Some((i, &x)) = it.nth(1) {
183 let (i, &x) = xs.iter().enumerate().nth(3).unwrap();
189 fn test_iterator_enumerate_count() {
190 let xs = [0, 1, 2, 3, 4, 5];
191 assert_eq!(xs.iter().count(), 6);
195 fn test_iterator_peekable() {
196 let xs = vec![0, 1, 2, 3, 4, 5];
197 let mut it = xs.iter().cloned().peekable();
199 assert_eq!(it.len(), 6);
200 assert_eq!(it.peek().unwrap(), &0);
201 assert_eq!(it.len(), 6);
202 assert_eq!(it.next().unwrap(), 0);
203 assert_eq!(it.len(), 5);
204 assert_eq!(it.next().unwrap(), 1);
205 assert_eq!(it.len(), 4);
206 assert_eq!(it.next().unwrap(), 2);
207 assert_eq!(it.len(), 3);
208 assert_eq!(it.peek().unwrap(), &3);
209 assert_eq!(it.len(), 3);
210 assert_eq!(it.peek().unwrap(), &3);
211 assert_eq!(it.len(), 3);
212 assert_eq!(it.next().unwrap(), 3);
213 assert_eq!(it.len(), 2);
214 assert_eq!(it.next().unwrap(), 4);
215 assert_eq!(it.len(), 1);
216 assert_eq!(it.peek().unwrap(), &5);
217 assert_eq!(it.len(), 1);
218 assert_eq!(it.next().unwrap(), 5);
219 assert_eq!(it.len(), 0);
220 assert!(it.peek().is_none());
221 assert_eq!(it.len(), 0);
222 assert!(it.next().is_none());
223 assert_eq!(it.len(), 0);
227 fn test_iterator_peekable_count() {
228 let xs = [0, 1, 2, 3, 4, 5];
230 let zs: [i32; 0] = [];
232 assert_eq!(xs.iter().peekable().count(), 6);
234 let mut it = xs.iter().peekable();
235 assert_eq!(it.peek(), Some(&&0));
236 assert_eq!(it.count(), 6);
238 assert_eq!(ys.iter().peekable().count(), 1);
240 let mut it = ys.iter().peekable();
241 assert_eq!(it.peek(), Some(&&10));
242 assert_eq!(it.count(), 1);
244 assert_eq!(zs.iter().peekable().count(), 0);
246 let mut it = zs.iter().peekable();
247 assert_eq!(it.peek(), None);
252 fn test_iterator_peekable_nth() {
253 let xs = [0, 1, 2, 3, 4, 5];
254 let mut it = xs.iter().peekable();
256 assert_eq!(it.peek(), Some(&&0));
257 assert_eq!(it.nth(0), Some(&0));
258 assert_eq!(it.peek(), Some(&&1));
259 assert_eq!(it.nth(1), Some(&2));
260 assert_eq!(it.peek(), Some(&&3));
261 assert_eq!(it.nth(2), Some(&5));
262 assert_eq!(it.next(), None);
266 fn test_iterator_peekable_last() {
267 let xs = [0, 1, 2, 3, 4, 5];
270 let mut it = xs.iter().peekable();
271 assert_eq!(it.peek(), Some(&&0));
272 assert_eq!(it.last(), Some(&5));
274 let mut it = ys.iter().peekable();
275 assert_eq!(it.peek(), Some(&&0));
276 assert_eq!(it.last(), Some(&0));
280 fn test_iterator_take_while() {
281 let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19];
282 let ys = [0, 1, 2, 3, 5, 13];
283 let it = xs.iter().take_while(|&x| *x < 15);
286 assert_eq!(*x, ys[i]);
289 assert_eq!(i, ys.len());
293 fn test_iterator_skip_while() {
294 let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19];
295 let ys = [15, 16, 17, 19];
296 let it = xs.iter().skip_while(|&x| *x < 15);
299 assert_eq!(*x, ys[i]);
302 assert_eq!(i, ys.len());
306 fn test_iterator_skip() {
307 let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19, 20, 30];
308 let ys = [13, 15, 16, 17, 19, 20, 30];
309 let mut it = xs.iter().skip(5);
311 while let Some(&x) = it.next() {
312 assert_eq!(x, ys[i]);
314 assert_eq!(it.len(), xs.len()-5-i);
316 assert_eq!(i, ys.len());
317 assert_eq!(it.len(), 0);
321 fn test_iterator_skip_doubleended() {
322 let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19, 20, 30];
323 let mut it = xs.iter().rev().skip(5);
324 assert_eq!(it.next(), Some(&15));
325 assert_eq!(it.by_ref().rev().next(), Some(&0));
326 assert_eq!(it.next(), Some(&13));
327 assert_eq!(it.by_ref().rev().next(), Some(&1));
328 assert_eq!(it.next(), Some(&5));
329 assert_eq!(it.by_ref().rev().next(), Some(&2));
330 assert_eq!(it.next(), Some(&3));
331 assert_eq!(it.next(), None);
332 let mut it = xs.iter().rev().skip(5).rev();
333 assert_eq!(it.next(), Some(&0));
334 assert_eq!(it.rev().next(), Some(&15));
335 let mut it_base = xs.iter();
337 let mut it = it_base.by_ref().skip(5).rev();
338 assert_eq!(it.next(), Some(&30));
339 assert_eq!(it.next(), Some(&20));
340 assert_eq!(it.next(), Some(&19));
341 assert_eq!(it.next(), Some(&17));
342 assert_eq!(it.next(), Some(&16));
343 assert_eq!(it.next(), Some(&15));
344 assert_eq!(it.next(), Some(&13));
345 assert_eq!(it.next(), None);
347 // make sure the skipped parts have not been consumed
348 assert_eq!(it_base.next(), Some(&0));
349 assert_eq!(it_base.next(), Some(&1));
350 assert_eq!(it_base.next(), Some(&2));
351 assert_eq!(it_base.next(), Some(&3));
352 assert_eq!(it_base.next(), Some(&5));
353 assert_eq!(it_base.next(), None);
354 let it = xs.iter().skip(5).rev();
355 assert_eq!(it.last(), Some(&13));
359 fn test_iterator_skip_nth() {
360 let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19, 20, 30];
362 let mut it = xs.iter().skip(0);
363 assert_eq!(it.nth(0), Some(&0));
364 assert_eq!(it.nth(1), Some(&2));
366 let mut it = xs.iter().skip(5);
367 assert_eq!(it.nth(0), Some(&13));
368 assert_eq!(it.nth(1), Some(&16));
370 let mut it = xs.iter().skip(12);
371 assert_eq!(it.nth(0), None);
376 fn test_iterator_skip_count() {
377 let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19, 20, 30];
379 assert_eq!(xs.iter().skip(0).count(), 12);
380 assert_eq!(xs.iter().skip(1).count(), 11);
381 assert_eq!(xs.iter().skip(11).count(), 1);
382 assert_eq!(xs.iter().skip(12).count(), 0);
383 assert_eq!(xs.iter().skip(13).count(), 0);
387 fn test_iterator_skip_last() {
388 let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19, 20, 30];
390 assert_eq!(xs.iter().skip(0).last(), Some(&30));
391 assert_eq!(xs.iter().skip(1).last(), Some(&30));
392 assert_eq!(xs.iter().skip(11).last(), Some(&30));
393 assert_eq!(xs.iter().skip(12).last(), None);
394 assert_eq!(xs.iter().skip(13).last(), None);
396 let mut it = xs.iter().skip(5);
397 assert_eq!(it.next(), Some(&13));
398 assert_eq!(it.last(), Some(&30));
402 fn test_iterator_take() {
403 let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19];
404 let ys = [0, 1, 2, 3, 5];
405 let mut it = xs.iter().take(5);
407 assert_eq!(it.len(), 5);
408 while let Some(&x) = it.next() {
409 assert_eq!(x, ys[i]);
411 assert_eq!(it.len(), 5-i);
413 assert_eq!(i, ys.len());
414 assert_eq!(it.len(), 0);
418 fn test_iterator_take_nth() {
419 let xs = [0, 1, 2, 4, 5];
420 let mut it = xs.iter();
422 let mut take = it.by_ref().take(3);
424 while let Some(&x) = take.nth(0) {
429 assert_eq!(it.nth(1), Some(&5));
430 assert_eq!(it.nth(0), None);
432 let xs = [0, 1, 2, 3, 4];
433 let mut it = xs.iter().take(7);
435 while let Some(&x) = it.nth(1) {
442 fn test_iterator_take_short() {
443 let xs = [0, 1, 2, 3];
444 let ys = [0, 1, 2, 3];
445 let mut it = xs.iter().take(5);
447 assert_eq!(it.len(), 4);
448 while let Some(&x) = it.next() {
449 assert_eq!(x, ys[i]);
451 assert_eq!(it.len(), 4-i);
453 assert_eq!(i, ys.len());
454 assert_eq!(it.len(), 0);
458 fn test_iterator_scan() {
459 // test the type inference
460 fn add(old: &mut isize, new: &usize) -> Option<f64> {
461 *old += *new as isize;
464 let xs = [0, 1, 2, 3, 4];
465 let ys = [0f64, 1.0, 3.0, 6.0, 10.0];
467 let it = xs.iter().scan(0, add);
470 assert_eq!(x, ys[i]);
473 assert_eq!(i, ys.len());
477 fn test_iterator_flat_map() {
479 let ys = [0, 1, 2, 3, 4, 5, 6, 7, 8];
480 let it = xs.iter().flat_map(|&x| (x..).step_by(1).take(3));
483 assert_eq!(x, ys[i]);
486 assert_eq!(i, ys.len());
491 let xs = [1, 2, 3, 4];
497 .collect::<Vec<usize>>();
499 assert_eq!(n, xs.len());
500 assert_eq!(&xs[..], &ys[..]);
506 let it = (0..).step_by(1).take(cycle_len).cycle();
507 assert_eq!(it.size_hint(), (usize::MAX, None));
508 for (i, x) in it.take(100).enumerate() {
509 assert_eq!(i % cycle_len, x);
512 let mut it = (0..).step_by(1).take(0).cycle();
513 assert_eq!(it.size_hint(), (0, Some(0)));
514 assert_eq!(it.next(), None);
518 fn test_iterator_nth() {
519 let v: &[_] = &[0, 1, 2, 3, 4];
520 for i in 0..v.len() {
521 assert_eq!(v.iter().nth(i).unwrap(), &v[i]);
523 assert_eq!(v.iter().nth(v.len()), None);
527 fn test_iterator_last() {
528 let v: &[_] = &[0, 1, 2, 3, 4];
529 assert_eq!(v.iter().last().unwrap(), &4);
530 assert_eq!(v[..1].iter().last().unwrap(), &0);
534 fn test_iterator_len() {
535 let v: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
536 assert_eq!(v[..4].iter().count(), 4);
537 assert_eq!(v[..10].iter().count(), 10);
538 assert_eq!(v[..0].iter().count(), 0);
542 fn test_iterator_sum() {
543 let v: &[i32] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
544 assert_eq!(v[..4].iter().cloned().sum::<i32>(), 6);
545 assert_eq!(v.iter().cloned().sum::<i32>(), 55);
546 assert_eq!(v[..0].iter().cloned().sum::<i32>(), 0);
550 fn test_iterator_product() {
551 let v: &[i32] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
552 assert_eq!(v[..4].iter().cloned().product::<i32>(), 0);
553 assert_eq!(v[1..5].iter().cloned().product::<i32>(), 24);
554 assert_eq!(v[..0].iter().cloned().product::<i32>(), 1);
558 fn test_iterator_max() {
559 let v: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
560 assert_eq!(v[..4].iter().cloned().max(), Some(3));
561 assert_eq!(v.iter().cloned().max(), Some(10));
562 assert_eq!(v[..0].iter().cloned().max(), None);
566 fn test_iterator_min() {
567 let v: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
568 assert_eq!(v[..4].iter().cloned().min(), Some(0));
569 assert_eq!(v.iter().cloned().min(), Some(0));
570 assert_eq!(v[..0].iter().cloned().min(), None);
574 fn test_iterator_size_hint() {
575 let c = (0..).step_by(1);
576 let v: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9];
577 let v2 = &[10, 11, 12];
580 assert_eq!(c.size_hint(), (usize::MAX, None));
581 assert_eq!(vi.clone().size_hint(), (10, Some(10)));
583 assert_eq!(c.clone().take(5).size_hint(), (5, Some(5)));
584 assert_eq!(c.clone().skip(5).size_hint().1, None);
585 assert_eq!(c.clone().take_while(|_| false).size_hint(), (0, None));
586 assert_eq!(c.clone().skip_while(|_| false).size_hint(), (0, None));
587 assert_eq!(c.clone().enumerate().size_hint(), (usize::MAX, None));
588 assert_eq!(c.clone().chain(vi.clone().cloned()).size_hint(), (usize::MAX, None));
589 assert_eq!(c.clone().zip(vi.clone()).size_hint(), (10, Some(10)));
590 assert_eq!(c.clone().scan(0, |_,_| Some(0)).size_hint(), (0, None));
591 assert_eq!(c.clone().filter(|_| false).size_hint(), (0, None));
592 assert_eq!(c.clone().map(|_| 0).size_hint(), (usize::MAX, None));
593 assert_eq!(c.filter_map(|_| Some(0)).size_hint(), (0, None));
595 assert_eq!(vi.clone().take(5).size_hint(), (5, Some(5)));
596 assert_eq!(vi.clone().take(12).size_hint(), (10, Some(10)));
597 assert_eq!(vi.clone().skip(3).size_hint(), (7, Some(7)));
598 assert_eq!(vi.clone().skip(12).size_hint(), (0, Some(0)));
599 assert_eq!(vi.clone().take_while(|_| false).size_hint(), (0, Some(10)));
600 assert_eq!(vi.clone().skip_while(|_| false).size_hint(), (0, Some(10)));
601 assert_eq!(vi.clone().enumerate().size_hint(), (10, Some(10)));
602 assert_eq!(vi.clone().chain(v2).size_hint(), (13, Some(13)));
603 assert_eq!(vi.clone().zip(v2).size_hint(), (3, Some(3)));
604 assert_eq!(vi.clone().scan(0, |_,_| Some(0)).size_hint(), (0, Some(10)));
605 assert_eq!(vi.clone().filter(|_| false).size_hint(), (0, Some(10)));
606 assert_eq!(vi.clone().map(|&i| i+1).size_hint(), (10, Some(10)));
607 assert_eq!(vi.filter_map(|_| Some(0)).size_hint(), (0, Some(10)));
612 let a = vec![1, 2, 3, 4, 5];
613 let b: Vec<isize> = a.iter().cloned().collect();
619 // FIXME (#22405): Replace `Box::new` with `box` here when/if possible.
620 let v: Box<[isize]> = Box::new([1, 2, 3, 4, 5]);
621 assert!(v.iter().all(|&x| x < 10));
622 assert!(!v.iter().all(|&x| x % 2 == 0));
623 assert!(!v.iter().all(|&x| x > 100));
624 assert!(v[..0].iter().all(|_| panic!()));
629 // FIXME (#22405): Replace `Box::new` with `box` here when/if possible.
630 let v: Box<[isize]> = Box::new([1, 2, 3, 4, 5]);
631 assert!(v.iter().any(|&x| x < 10));
632 assert!(v.iter().any(|&x| x % 2 == 0));
633 assert!(!v.iter().any(|&x| x > 100));
634 assert!(!v[..0].iter().any(|_| panic!()));
639 let v: &[isize] = &[1, 3, 9, 27, 103, 14, 11];
640 assert_eq!(*v.iter().find(|&&x| x & 1 == 0).unwrap(), 14);
641 assert_eq!(*v.iter().find(|&&x| x % 3 == 0).unwrap(), 3);
642 assert!(v.iter().find(|&&x| x % 12 == 0).is_none());
647 let v = &[1, 3, 9, 27, 103, 14, 11];
648 assert_eq!(v.iter().position(|x| *x & 1 == 0).unwrap(), 5);
649 assert_eq!(v.iter().position(|x| *x % 3 == 0).unwrap(), 1);
650 assert!(v.iter().position(|x| *x % 12 == 0).is_none());
655 let xs = &[1, 2, 2, 1, 5, 9, 0, 2];
656 assert_eq!(xs.iter().filter(|x| **x == 2).count(), 3);
657 assert_eq!(xs.iter().filter(|x| **x == 5).count(), 1);
658 assert_eq!(xs.iter().filter(|x| **x == 95).count(), 0);
662 fn test_max_by_key() {
663 let xs: &[isize] = &[-3, 0, 1, 5, -10];
664 assert_eq!(*xs.iter().max_by_key(|x| x.abs()).unwrap(), -10);
669 let xs: &[isize] = &[-3, 0, 1, 5, -10];
670 assert_eq!(*xs.iter().max_by(|x, y| x.abs().cmp(&y.abs())).unwrap(), -10);
674 fn test_min_by_key() {
675 let xs: &[isize] = &[-3, 0, 1, 5, -10];
676 assert_eq!(*xs.iter().min_by_key(|x| x.abs()).unwrap(), 0);
681 let xs: &[isize] = &[-3, 0, 1, 5, -10];
682 assert_eq!(*xs.iter().min_by(|x, y| x.abs().cmp(&y.abs())).unwrap(), 0);
688 // sum the first five values
689 let partial_sum = xs.by_ref().take(5).fold(0, |a, b| a + b);
690 assert_eq!(partial_sum, 10);
691 assert_eq!(xs.next(), Some(5));
696 let xs = [2, 4, 6, 8, 10, 12, 14, 16];
697 let mut it = xs.iter();
700 assert!(it.rev().cloned().collect::<Vec<isize>>() ==
701 vec![16, 14, 12, 10, 8, 6]);
706 let xs = [2, 4, 6, 8];
708 let mut it = xs.iter().cloned();
709 assert_eq!(it.len(), 4);
710 assert_eq!(it.next(), Some(2));
711 assert_eq!(it.len(), 3);
712 assert_eq!(it.next(), Some(4));
713 assert_eq!(it.len(), 2);
714 assert_eq!(it.next_back(), Some(8));
715 assert_eq!(it.len(), 1);
716 assert_eq!(it.next_back(), Some(6));
717 assert_eq!(it.len(), 0);
718 assert_eq!(it.next_back(), None);
722 fn test_double_ended_map() {
723 let xs = [1, 2, 3, 4, 5, 6];
724 let mut it = xs.iter().map(|&x| x * -1);
725 assert_eq!(it.next(), Some(-1));
726 assert_eq!(it.next(), Some(-2));
727 assert_eq!(it.next_back(), Some(-6));
728 assert_eq!(it.next_back(), Some(-5));
729 assert_eq!(it.next(), Some(-3));
730 assert_eq!(it.next_back(), Some(-4));
731 assert_eq!(it.next(), None);
735 fn test_double_ended_enumerate() {
736 let xs = [1, 2, 3, 4, 5, 6];
737 let mut it = xs.iter().cloned().enumerate();
738 assert_eq!(it.next(), Some((0, 1)));
739 assert_eq!(it.next(), Some((1, 2)));
740 assert_eq!(it.next_back(), Some((5, 6)));
741 assert_eq!(it.next_back(), Some((4, 5)));
742 assert_eq!(it.next_back(), Some((3, 4)));
743 assert_eq!(it.next_back(), Some((2, 3)));
744 assert_eq!(it.next(), None);
748 fn test_double_ended_zip() {
749 let xs = [1, 2, 3, 4, 5, 6];
750 let ys = [1, 2, 3, 7];
751 let a = xs.iter().cloned();
752 let b = ys.iter().cloned();
753 let mut it = a.zip(b);
754 assert_eq!(it.next(), Some((1, 1)));
755 assert_eq!(it.next(), Some((2, 2)));
756 assert_eq!(it.next_back(), Some((4, 7)));
757 assert_eq!(it.next_back(), Some((3, 3)));
758 assert_eq!(it.next(), None);
762 fn test_double_ended_filter() {
763 let xs = [1, 2, 3, 4, 5, 6];
764 let mut it = xs.iter().filter(|&x| *x & 1 == 0);
765 assert_eq!(it.next_back().unwrap(), &6);
766 assert_eq!(it.next_back().unwrap(), &4);
767 assert_eq!(it.next().unwrap(), &2);
768 assert_eq!(it.next_back(), None);
772 fn test_double_ended_filter_map() {
773 let xs = [1, 2, 3, 4, 5, 6];
774 let mut it = xs.iter().filter_map(|&x| if x & 1 == 0 { Some(x * 2) } else { None });
775 assert_eq!(it.next_back().unwrap(), 12);
776 assert_eq!(it.next_back().unwrap(), 8);
777 assert_eq!(it.next().unwrap(), 4);
778 assert_eq!(it.next_back(), None);
782 fn test_double_ended_chain() {
783 let xs = [1, 2, 3, 4, 5];
785 let mut it = xs.iter().chain(&ys).rev();
786 assert_eq!(it.next().unwrap(), &11);
787 assert_eq!(it.next().unwrap(), &9);
788 assert_eq!(it.next_back().unwrap(), &1);
789 assert_eq!(it.next_back().unwrap(), &2);
790 assert_eq!(it.next_back().unwrap(), &3);
791 assert_eq!(it.next_back().unwrap(), &4);
792 assert_eq!(it.next_back().unwrap(), &5);
793 assert_eq!(it.next_back().unwrap(), &7);
794 assert_eq!(it.next_back(), None);
797 // test that .chain() is well behaved with an unfused iterator
798 struct CrazyIterator(bool);
799 impl CrazyIterator { fn new() -> CrazyIterator { CrazyIterator(false) } }
800 impl Iterator for CrazyIterator {
802 fn next(&mut self) -> Option<i32> {
803 if self.0 { Some(99) } else { self.0 = true; None }
807 impl DoubleEndedIterator for CrazyIterator {
808 fn next_back(&mut self) -> Option<i32> {
813 assert_eq!(CrazyIterator::new().chain(0..10).rev().last(), Some(0));
814 assert!((0..10).chain(CrazyIterator::new()).rev().any(|i| i == 0));
818 fn test_rposition() {
819 fn f(xy: &(isize, char)) -> bool { let (_x, y) = *xy; y == 'b' }
820 fn g(xy: &(isize, char)) -> bool { let (_x, y) = *xy; y == 'd' }
821 let v = [(0, 'a'), (1, 'b'), (2, 'c'), (3, 'b')];
823 assert_eq!(v.iter().rposition(f), Some(3));
824 assert!(v.iter().rposition(g).is_none());
829 fn test_rposition_panic() {
830 let v: [(Box<_>, Box<_>); 4] =
831 [(box 0, box 0), (box 0, box 0),
832 (box 0, box 0), (box 0, box 0)];
834 v.iter().rposition(|_elt| {
845 fn test_double_ended_flat_map() {
848 let mut it = u.iter().flat_map(|x| &v[*x..v.len()]);
849 assert_eq!(it.next_back().unwrap(), &8);
850 assert_eq!(it.next().unwrap(), &5);
851 assert_eq!(it.next_back().unwrap(), &7);
852 assert_eq!(it.next_back().unwrap(), &6);
853 assert_eq!(it.next_back().unwrap(), &8);
854 assert_eq!(it.next().unwrap(), &6);
855 assert_eq!(it.next_back().unwrap(), &7);
856 assert_eq!(it.next_back(), None);
857 assert_eq!(it.next(), None);
858 assert_eq!(it.next_back(), None);
862 fn test_double_ended_range() {
863 assert_eq!((11..14).rev().collect::<Vec<_>>(), [13, 12, 11]);
864 for _ in (10..0).rev() {
865 panic!("unreachable");
868 assert_eq!((11..14).rev().collect::<Vec<_>>(), [13, 12, 11]);
869 for _ in (10..0).rev() {
870 panic!("unreachable");
876 assert_eq!((0..5).collect::<Vec<_>>(), [0, 1, 2, 3, 4]);
877 assert_eq!((-10..-1).collect::<Vec<_>>(), [-10, -9, -8, -7, -6, -5, -4, -3, -2]);
878 assert_eq!((0..5).rev().collect::<Vec<_>>(), [4, 3, 2, 1, 0]);
879 assert_eq!((200..-5).count(), 0);
880 assert_eq!((200..-5).rev().count(), 0);
881 assert_eq!((200..200).count(), 0);
882 assert_eq!((200..200).rev().count(), 0);
884 assert_eq!((0..100).size_hint(), (100, Some(100)));
885 // this test is only meaningful when sizeof usize < sizeof u64
886 assert_eq!((usize::MAX - 1..usize::MAX).size_hint(), (1, Some(1)));
887 assert_eq!((-10..-1).size_hint(), (9, Some(9)));
888 assert_eq!((-1..-10).size_hint(), (0, Some(0)));
890 assert_eq!((-70..58).size_hint(), (128, Some(128)));
891 assert_eq!((-128..127).size_hint(), (255, Some(255)));
892 assert_eq!((-2..isize::MAX).size_hint(),
893 (isize::MAX as usize + 2, Some(isize::MAX as usize + 2)));
897 fn test_range_step() {
898 assert_eq!((0..20).step_by(5).collect::<Vec<isize>>(), [0, 5, 10, 15]);
899 assert_eq!((20..0).step_by(-5).collect::<Vec<isize>>(), [20, 15, 10, 5]);
900 assert_eq!((20..0).step_by(-6).collect::<Vec<isize>>(), [20, 14, 8, 2]);
901 assert_eq!((200..255).step_by(50).collect::<Vec<u8>>(), [200, 250]);
902 assert_eq!((200..-5).step_by(1).collect::<Vec<isize>>(), []);
903 assert_eq!((200..200).step_by(1).collect::<Vec<isize>>(), []);
905 assert_eq!((0..20).step_by(1).size_hint(), (20, Some(20)));
906 assert_eq!((0..20).step_by(21).size_hint(), (1, Some(1)));
907 assert_eq!((0..20).step_by(5).size_hint(), (4, Some(4)));
908 assert_eq!((20..0).step_by(-5).size_hint(), (4, Some(4)));
909 assert_eq!((20..0).step_by(-6).size_hint(), (4, Some(4)));
910 assert_eq!((20..-5).step_by(1).size_hint(), (0, Some(0)));
911 assert_eq!((20..20).step_by(1).size_hint(), (0, Some(0)));
912 assert_eq!((0..1).step_by(0).size_hint(), (0, None));
913 assert_eq!((i8::MAX..i8::MIN).step_by(i8::MIN).size_hint(), (2, Some(2)));
914 assert_eq!((i16::MIN..i16::MAX).step_by(i16::MAX).size_hint(), (3, Some(3)));
915 assert_eq!((isize::MIN..isize::MAX).step_by(1).size_hint(), (usize::MAX, Some(usize::MAX)));
920 let mut it = repeat(42);
921 assert_eq!(it.next(), Some(42));
922 assert_eq!(it.next(), Some(42));
923 assert_eq!(it.next(), Some(42));
929 assert_eq!(it.len(), 3);
930 assert_eq!(it.next(), Some(0));
931 assert_eq!(it.len(), 2);
932 assert_eq!(it.next(), Some(1));
933 assert_eq!(it.len(), 1);
934 assert_eq!(it.next(), Some(2));
935 assert_eq!(it.len(), 0);
936 assert_eq!(it.next(), None);
937 assert_eq!(it.len(), 0);
938 assert_eq!(it.next(), None);
939 assert_eq!(it.len(), 0);
940 assert_eq!(it.next(), None);
941 assert_eq!(it.len(), 0);
947 let mut it = xs.iter();
949 assert_eq!(it.len(), 3);
950 assert_eq!(it.nth(2), Some(&2));
951 assert_eq!(it.len(), 0);
952 assert_eq!(it.nth(2), None);
953 assert_eq!(it.len(), 0);
957 fn test_fuse_last() {
961 assert_eq!(it.len(), 3);
962 assert_eq!(it.last(), Some(&2));
966 fn test_fuse_count() {
970 assert_eq!(it.len(), 3);
971 assert_eq!(it.count(), 3);
972 // Can't check len now because count consumes.
977 let mut it = once(42);
978 assert_eq!(it.next(), Some(42));
979 assert_eq!(it.next(), None);
984 let mut it = empty::<i32>();
985 assert_eq!(it.next(), None);
989 fn bench_rposition(b: &mut Bencher) {
990 let it: Vec<usize> = (0..300).collect();
992 it.iter().rposition(|&x| x <= 150);
997 fn bench_skip_while(b: &mut Bencher) {
1001 it.skip_while(|&x| { sum += x; sum < 4000 }).all(|_| true);
1006 fn bench_multiple_take(b: &mut Bencher) {
1007 let mut it = (0..42).cycle();
1009 let n = it.next().unwrap();
1011 it.clone().take(it.next().unwrap()).all(|_| true);
1016 fn scatter(x: i32) -> i32 { (x * 31) % 127 }
1019 fn bench_max_by_key(b: &mut Bencher) {
1022 it.max_by_key(|&x| scatter(x))
1026 // http://www.reddit.com/r/rust/comments/31syce/using_iterators_to_find_the_index_of_the_min_or/
1028 fn bench_max_by_key2(b: &mut Bencher) {
1029 fn max_index_iter(array: &[i32]) -> usize {
1030 array.iter().enumerate().max_by_key(|&(_, item)| item).unwrap().0
1033 let mut data = vec![0; 1638];
1036 b.iter(|| max_index_iter(&data));
1040 fn bench_max(b: &mut Bencher) {
1043 it.map(scatter).max()
1047 pub fn copy_zip(xs: &[u8], ys: &mut [u8]) {
1048 for (a, b) in ys.iter_mut().zip(xs) {
1053 pub fn add_zip(xs: &[f32], ys: &mut [f32]) {
1054 for (a, b) in ys.iter_mut().zip(xs) {
1060 fn bench_zip_copy(b: &mut Bencher) {
1061 let source = vec![0u8; 16 * 1024];
1062 let mut dst = black_box(vec![0u8; 16 * 1024]);
1064 copy_zip(&source, &mut dst)
1069 fn bench_zip_add(b: &mut Bencher) {
1070 let source = vec![1.; 16 * 1024];
1071 let mut dst = vec![0.; 16 * 1024];
1073 add_zip(&source, &mut dst)