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1 ///////////////////////////////////////////////////////////////////////////////
2 //
3 // Copyright (c) 2015 Microsoft Corporation. All rights reserved.
4 //
5 // This code is licensed under the MIT License (MIT).
6 //
7 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
8 // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
9 // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
10 // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
11 // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
12 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
13 // THE SOFTWARE.
14 //
15 ///////////////////////////////////////////////////////////////////////////////
16 
17 #include <UnitTest++/UnitTest++.h>
18 #include <gsl/multi_span>
19 
20 #include <iostream>
21 #include <list>
22 #include <map>
23 #include <memory>
24 #include <string>
25 #include <vector>
26 
27 using namespace std;
28 using namespace gsl;
29 
30 namespace
31 {
32 struct BaseClass
33 {
34 };
35 struct DerivedClass : BaseClass
36 {
37 };
38 }
39 
SUITE(multi_span_tests)40 SUITE(multi_span_tests)
41 {
42 
43     TEST(default_constructor)
44     {
45         {
46             multi_span<int> s;
47             CHECK(s.length() == 0 && s.data() == nullptr);
48 
49             multi_span<const int> cs;
50             CHECK(cs.length() == 0 && cs.data() == nullptr);
51         }
52 
53         {
54             multi_span<int, 0> s;
55             CHECK(s.length() == 0 && s.data() == nullptr);
56 
57             multi_span<const int, 0> cs;
58             CHECK(cs.length() == 0 && cs.data() == nullptr);
59         }
60 
61         {
62 #ifdef CONFIRM_COMPILATION_ERRORS
63             multi_span<int, 1> s;
64             CHECK(s.length() == 1 && s.data() == nullptr); // explains why it can't compile
65 #endif
66         }
67 
68         {
69             multi_span<int> s{};
70             CHECK(s.length() == 0 && s.data() == nullptr);
71 
72             multi_span<const int> cs{};
73             CHECK(cs.length() == 0 && cs.data() == nullptr);
74         }
75     }
76 
77     TEST(from_nullptr_constructor)
78     {
79         {
80             multi_span<int> s = nullptr;
81             CHECK(s.length() == 0 && s.data() == nullptr);
82 
83             multi_span<const int> cs = nullptr;
84             CHECK(cs.length() == 0 && cs.data() == nullptr);
85         }
86 
87         {
88             multi_span<int, 0> s = nullptr;
89             CHECK(s.length() == 0 && s.data() == nullptr);
90 
91             multi_span<const int, 0> cs = nullptr;
92             CHECK(cs.length() == 0 && cs.data() == nullptr);
93         }
94 
95         {
96 #ifdef CONFIRM_COMPILATION_ERRORS
97             multi_span<int, 1> s = nullptr;
98             CHECK(s.length() == 1 && s.data() == nullptr); // explains why it can't compile
99 #endif
100         }
101 
102         {
103             multi_span<int> s{nullptr};
104             CHECK(s.length() == 0 && s.data() == nullptr);
105 
106             multi_span<const int> cs{nullptr};
107             CHECK(cs.length() == 0 && cs.data() == nullptr);
108         }
109 
110         {
111             multi_span<int*> s{nullptr};
112             CHECK(s.length() == 0 && s.data() == nullptr);
113 
114             multi_span<const int*> cs{nullptr};
115             CHECK(cs.length() == 0 && cs.data() == nullptr);
116         }
117     }
118 
119     TEST(from_nullptr_length_constructor)
120     {
121         {
122             multi_span<int> s{nullptr, 0};
123             CHECK(s.length() == 0 && s.data() == nullptr);
124 
125             multi_span<const int> cs{nullptr, 0};
126             CHECK(cs.length() == 0 && cs.data() == nullptr);
127         }
128 
129         {
130             multi_span<int, 0> s{nullptr, 0};
131             CHECK(s.length() == 0 && s.data() == nullptr);
132 
133             multi_span<const int, 0> cs{nullptr, 0};
134             CHECK(cs.length() == 0 && cs.data() == nullptr);
135         }
136 
137         {
138 #ifdef CONFIRM_COMPILATION_ERRORS
139             multi_span<int, 1> s{nullptr, 0};
140             CHECK(s.length() == 1 && s.data() == nullptr); // explains why it can't compile
141 #endif
142         }
143 
144         {
145             auto workaround_macro = []() { multi_span<int> s{nullptr, 1}; };
146             CHECK_THROW(workaround_macro(), fail_fast);
147 
148             auto const_workaround_macro = []() { multi_span<const int> cs{nullptr, 1}; };
149             CHECK_THROW(const_workaround_macro(), fail_fast);
150         }
151 
152         {
153             auto workaround_macro = []() { multi_span<int, 0> s{nullptr, 1}; };
154             CHECK_THROW(workaround_macro(), fail_fast);
155 
156             auto const_workaround_macro = []() { multi_span<const int, 0> s{nullptr, 1}; };
157             CHECK_THROW(const_workaround_macro(), fail_fast);
158         }
159 
160         {
161             multi_span<int*> s{nullptr, 0};
162             CHECK(s.length() == 0 && s.data() == nullptr);
163 
164             multi_span<const int*> cs{nullptr, 0};
165             CHECK(cs.length() == 0 && cs.data() == nullptr);
166         }
167     }
168 
169     TEST(from_element_constructor)
170     {
171         int i = 5;
172 
173         {
174             multi_span<int> s = i;
175             CHECK(s.length() == 1 && s.data() == &i);
176             CHECK(s[0] == 5);
177 
178             multi_span<const int> cs = i;
179             CHECK(cs.length() == 1 && cs.data() == &i);
180             CHECK(cs[0] == 5);
181         }
182 
183         {
184 #ifdef CONFIRM_COMPILATION_ERRORS
185             const j = 1;
186             multi_span<int, 0> s = j;
187 #endif
188         }
189 
190         {
191 #ifdef CONFIRM_COMPILATION_ERRORS
192             multi_span<int, 0> s = i;
193             CHECK(s.length() == 0 && s.data() == &i);
194 #endif
195         }
196 
197         {
198             multi_span<int, 1> s = i;
199             CHECK(s.length() == 1 && s.data() == &i);
200             CHECK(s[0] == 5);
201         }
202 
203         {
204 #ifdef CONFIRM_COMPILATION_ERRORS
205             multi_span<int, 2> s = i;
206             CHECK(s.length() == 2 && s.data() == &i);
207 #endif
208         }
209 
210         {
211 #ifdef CONFIRM_COMPILATION_ERRORS
212             auto get_a_temp = []() -> int { return 4; };
213             auto use_a_span = [](multi_span<int> s) { (void) s; };
214             use_a_span(get_a_temp());
215 #endif
216         }
217     }
218 
219     TEST(from_pointer_length_constructor)
220     {
221         int arr[4] = {1, 2, 3, 4};
222 
223         {
224             multi_span<int> s{&arr[0], 2};
225             CHECK(s.length() == 2 && s.data() == &arr[0]);
226             CHECK(s[0] == 1 && s[1] == 2);
227         }
228 
229         {
230             multi_span<int, 2> s{&arr[0], 2};
231             CHECK(s.length() == 2 && s.data() == &arr[0]);
232             CHECK(s[0] == 1 && s[1] == 2);
233         }
234 
235         {
236             int* p = nullptr;
237             multi_span<int> s{p, 0};
238             CHECK(s.length() == 0 && s.data() == nullptr);
239         }
240 
241         {
242             int* p = nullptr;
243             auto workaround_macro = [=]() { multi_span<int> s{p, 2}; };
244             CHECK_THROW(workaround_macro(), fail_fast);
245         }
246     }
247 
248     TEST(from_pointer_pointer_constructor)
249     {
250         int arr[4] = {1, 2, 3, 4};
251 
252         {
253             multi_span<int> s{&arr[0], &arr[2]};
254             CHECK(s.length() == 2 && s.data() == &arr[0]);
255             CHECK(s[0] == 1 && s[1] == 2);
256         }
257 
258         {
259             multi_span<int, 2> s{&arr[0], &arr[2]};
260             CHECK(s.length() == 2 && s.data() == &arr[0]);
261             CHECK(s[0] == 1 && s[1] == 2);
262         }
263 
264         {
265             multi_span<int> s{&arr[0], &arr[0]};
266             CHECK(s.length() == 0 && s.data() == &arr[0]);
267         }
268 
269         {
270             multi_span<int, 0> s{&arr[0], &arr[0]};
271             CHECK(s.length() == 0 && s.data() == &arr[0]);
272         }
273 
274         {
275             auto workaround_macro = [&]() { multi_span<int> s{&arr[1], &arr[0]}; };
276             CHECK_THROW(workaround_macro(), fail_fast);
277         }
278 
279         {
280             int* p = nullptr;
281             auto workaround_macro = [&]() { multi_span<int> s{&arr[0], p}; };
282             CHECK_THROW(workaround_macro(), fail_fast);
283         }
284 
285         {
286             int* p = nullptr;
287             auto workaround_macro = [&]() { multi_span<int> s{p, p}; };
288             CHECK_THROW(workaround_macro(), fail_fast);
289         }
290 
291         {
292             int* p = nullptr;
293             auto workaround_macro = [&]() { multi_span<int> s{&arr[0], p}; };
294             CHECK_THROW(workaround_macro(), fail_fast);
295         }
296     }
297 
298     TEST(from_array_constructor)
299     {
300         int arr[5] = {1, 2, 3, 4, 5};
301 
302         {
303             multi_span<int> s{arr};
304             CHECK(s.length() == 5 && s.data() == &arr[0]);
305         }
306 
307         {
308             multi_span<int, 5> s{arr};
309             CHECK(s.length() == 5 && s.data() == &arr[0]);
310         }
311 
312         {
313 #ifdef CONFIRM_COMPILATION_ERRORS
314             multi_span<int, 6> s{arr};
315 #endif
316         }
317 
318         {
319             multi_span<int, 0> s{arr};
320             CHECK(s.length() == 0 && s.data() == &arr[0]);
321         }
322 
323         int arr2d[2][3] = {1, 2, 3, 4, 5, 6};
324 
325         {
326             multi_span<int> s{arr2d};
327             CHECK(s.length() == 6 && s.data() == &arr2d[0][0]);
328             CHECK(s[0] == 1 && s[5] == 6);
329         }
330 
331         {
332             multi_span<int, 0> s{arr2d};
333             CHECK(s.length() == 0 && s.data() == &arr2d[0][0]);
334         }
335 
336         {
337 #ifdef CONFIRM_COMPILATION_ERRORS
338             multi_span<int, 5> s{arr2d};
339 #endif
340         }
341 
342         {
343             multi_span<int, 6> s{arr2d};
344             CHECK(s.length() == 6 && s.data() == &arr2d[0][0]);
345             CHECK(s[0] == 1 && s[5] == 6);
346         }
347 
348         {
349 #ifdef CONFIRM_COMPILATION_ERRORS
350             multi_span<int, 7> s{arr2d};
351 #endif
352         }
353 
354         {
355             multi_span<int[3]> s{arr2d[0]};
356             CHECK(s.length() == 1 && s.data() == &arr2d[0]);
357         }
358 
359         {
360             multi_span<int, 2, 3> s{arr2d};
361             CHECK(s.length() == 6 && s.data() == &arr2d[0][0]);
362             auto workaround_macro = [&]() { return s[{1, 2}] == 6; };
363             CHECK(workaround_macro());
364         }
365 
366         {
367 #ifdef CONFIRM_COMPILATION_ERRORS
368             multi_span<int, 3, 3> s{arr2d};
369 #endif
370         }
371 
372         int arr3d[2][3][2] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12};
373 
374         {
375             multi_span<int> s{arr3d};
376             CHECK(s.length() == 12 && s.data() == &arr3d[0][0][0]);
377             CHECK(s[0] == 1 && s[11] == 12);
378         }
379 
380         {
381             multi_span<int, 0> s{arr3d};
382             CHECK(s.length() == 0 && s.data() == &arr3d[0][0][0]);
383         }
384 
385         {
386 #ifdef CONFIRM_COMPILATION_ERRORS
387             multi_span<int, 11> s{arr3d};
388 #endif
389         }
390 
391         {
392             multi_span<int, 12> s{arr3d};
393             CHECK(s.length() == 12 && s.data() == &arr3d[0][0][0]);
394             CHECK(s[0] == 1 && s[5] == 6);
395         }
396 
397         {
398 #ifdef CONFIRM_COMPILATION_ERRORS
399             multi_span<int, 13> s{arr3d};
400 #endif
401         }
402 
403         {
404             multi_span<int[3][2]> s{arr3d[0]};
405             CHECK(s.length() == 1 && s.data() == &arr3d[0]);
406         }
407 
408         {
409             multi_span<int, 3, 2, 2> s{arr3d};
410             CHECK(s.length() == 12 && s.data() == &arr3d[0][0][0]);
411             auto workaround_macro = [&]() { return s[{2, 1, 0}] == 11; };
412             CHECK(workaround_macro());
413         }
414 
415         {
416 #ifdef CONFIRM_COMPILATION_ERRORS
417             multi_span<int, 3, 3, 3> s{arr3d};
418 #endif
419         }
420     }
421 
422     TEST(from_dynamic_array_constructor)
423     {
424         double(*arr)[3][4] = new double[100][3][4];
425 
426         {
427             multi_span<double, dynamic_range, 3, 4> s(arr, 10);
428             CHECK(s.length() == 120 && s.data() == &arr[0][0][0]);
429             CHECK_THROW(s[10][3][4], fail_fast);
430         }
431 
432         {
433             multi_span<double, dynamic_range, 4, 3> s(arr, 10);
434             CHECK(s.length() == 120 && s.data() == &arr[0][0][0]);
435         }
436 
437         {
438             multi_span<double> s(arr, 10);
439             CHECK(s.length() == 120 && s.data() == &arr[0][0][0]);
440         }
441 
442         {
443             multi_span<double, dynamic_range, 3, 4> s(arr, 0);
444             CHECK(s.length() == 0 && s.data() == &arr[0][0][0]);
445         }
446 
447         delete[] arr;
448     }
449 
450     TEST(from_std_array_constructor)
451     {
452         std::array<int, 4> arr = {1, 2, 3, 4};
453 
454         {
455             multi_span<int> s{arr};
456             CHECK(s.size() == narrow_cast<ptrdiff_t>(arr.size()) && s.data() == arr.data());
457 
458             multi_span<const int> cs{arr};
459             CHECK(cs.size() == narrow_cast<ptrdiff_t>(arr.size()) && cs.data() == arr.data());
460         }
461 
462         {
463             multi_span<int, 4> s{arr};
464             CHECK(s.size() == narrow_cast<ptrdiff_t>(arr.size()) && s.data() == arr.data());
465 
466             multi_span<const int, 4> cs{arr};
467             CHECK(cs.size() == narrow_cast<ptrdiff_t>(arr.size()) && cs.data() == arr.data());
468         }
469 
470         {
471             multi_span<int, 2> s{arr};
472             CHECK(s.size() == 2 && s.data() == arr.data());
473 
474             multi_span<const int, 2> cs{arr};
475             CHECK(cs.size() == 2 && cs.data() == arr.data());
476         }
477 
478         {
479             multi_span<int, 0> s{arr};
480             CHECK(s.size() == 0 && s.data() == arr.data());
481 
482             multi_span<const int, 0> cs{arr};
483             CHECK(cs.size() == 0 && cs.data() == arr.data());
484         }
485 
486         // TODO This is currently an unsupported scenario. We will come back to it as we revise
487         // the multidimensional interface and what transformations between dimensionality look like
488         //{
489         //    multi_span<int, 2, 2> s{arr};
490         //    CHECK(s.size() == narrow_cast<ptrdiff_t>(arr.size()) && s.data() == arr.data());
491         //}
492 
493         {
494 #ifdef CONFIRM_COMPILATION_ERRORS
495             multi_span<int, 5> s{arr};
496 #endif
497         }
498 
499         {
500 #ifdef CONFIRM_COMPILATION_ERRORS
501             auto get_an_array = []() { return std::array<int, 4>{1, 2, 3, 4}; };
502             auto take_a_span = [](multi_span<int> s) { (void) s; };
503             // try to take a temporary std::array
504             take_a_span(get_an_array());
505 #endif
506         }
507     }
508 
509     TEST(from_const_std_array_constructor)
510     {
511         const std::array<int, 4> arr = {1, 2, 3, 4};
512 
513         {
514             multi_span<const int> s{arr};
515             CHECK(s.size() == narrow_cast<ptrdiff_t>(arr.size()) && s.data() == arr.data());
516         }
517 
518         {
519             multi_span<const int, 4> s{arr};
520             CHECK(s.size() == narrow_cast<ptrdiff_t>(arr.size()) && s.data() == arr.data());
521         }
522 
523         {
524             multi_span<const int, 2> s{arr};
525             CHECK(s.size() == 2 && s.data() == arr.data());
526         }
527 
528         {
529             multi_span<const int, 0> s{arr};
530             CHECK(s.size() == 0 && s.data() == arr.data());
531         }
532 
533         // TODO This is currently an unsupported scenario. We will come back to it as we revise
534         // the multidimensional interface and what transformations between dimensionality look like
535         //{
536         //    multi_span<int, 2, 2> s{arr};
537         //    CHECK(s.size() == narrow_cast<ptrdiff_t>(arr.size()) && s.data() == arr.data());
538         //}
539 
540         {
541 #ifdef CONFIRM_COMPILATION_ERRORS
542             multi_span<const int, 5> s{arr};
543 #endif
544         }
545 
546         {
547 #ifdef CONFIRM_COMPILATION_ERRORS
548             auto get_an_array = []() -> const std::array<int, 4> { return {1, 2, 3, 4}; };
549             auto take_a_span = [](multi_span<const int> s) { (void) s; };
550             // try to take a temporary std::array
551             take_a_span(get_an_array());
552 #endif
553         }
554     }
555 
556     TEST(from_container_constructor)
557     {
558         std::vector<int> v = {1, 2, 3};
559         const std::vector<int> cv = v;
560 
561         {
562             multi_span<int> s{v};
563             CHECK(s.size() == narrow_cast<std::ptrdiff_t>(v.size()) && s.data() == v.data());
564 
565             multi_span<const int> cs{v};
566             CHECK(cs.size() == narrow_cast<std::ptrdiff_t>(v.size()) && cs.data() == v.data());
567         }
568 
569         std::string str = "hello";
570         const std::string cstr = "hello";
571 
572         {
573 #ifdef CONFIRM_COMPILATION_ERRORS
574             multi_span<char> s{str};
575             CHECK(s.size() == narrow_cast<std::ptrdiff_t>(str.size()) && s.data() == str.data());
576 #endif
577             multi_span<const char> cs{str};
578             CHECK(cs.size() == narrow_cast<std::ptrdiff_t>(str.size()) && cs.data() == str.data());
579         }
580 
581         {
582 #ifdef CONFIRM_COMPILATION_ERRORS
583             multi_span<char> s{cstr};
584 #endif
585             multi_span<const char> cs{cstr};
586             CHECK(cs.size() == narrow_cast<std::ptrdiff_t>(cstr.size()) &&
587                   cs.data() == cstr.data());
588         }
589 
590         {
591 #ifdef CONFIRM_COMPILATION_ERRORS
592             auto get_temp_vector = []() -> std::vector<int> { return {}; };
593             auto use_span = [](multi_span<int> s) { (void) s; };
594             use_span(get_temp_vector());
595 #endif
596         }
597 
598         {
599 #ifdef CONFIRM_COMPILATION_ERRORS
600             auto get_temp_string = []() -> std::string { return {}; };
601             auto use_span = [](multi_span<char> s) { (void) s; };
602             use_span(get_temp_string());
603 #endif
604         }
605 
606         {
607 #ifdef CONFIRM_COMPILATION_ERRORS
608             auto get_temp_vector = []() -> const std::vector<int> { return {}; };
609             auto use_span = [](multi_span<const char> s) { (void) s; };
610             use_span(get_temp_vector());
611 #endif
612         }
613 
614         {
615 #ifdef CONFIRM_COMPILATION_ERRORS
616             auto get_temp_string = []() -> const std::string { return {}; };
617             auto use_span = [](multi_span<const char> s) { (void) s; };
618             use_span(get_temp_string());
619 #endif
620         }
621 
622         {
623 #ifdef CONFIRM_COMPILATION_ERRORS
624             std::map<int, int> m;
625             multi_span<int> s{m};
626 #endif
627         }
628     }
629 
630     TEST(from_convertible_span_constructor)
631     {
632 #ifdef CONFIRM_COMPILATION_ERRORS
633         multi_span<int, 7, 4, 2> av1(nullptr, b1);
634 
635         auto f = [&]() { multi_span<int, 7, 4, 2> av1(nullptr); };
636         CHECK_THROW(f(), fail_fast);
637 #endif
638 
639 #ifdef CONFIRM_COMPILATION_ERRORS
640         static_bounds<size_t, 7, dynamic_range, 2> b12(b11);
641         b12 = b11;
642         b11 = b12;
643 
644         multi_span<int, dynamic_range> av1 = nullptr;
645         multi_span<int, 7, dynamic_range, 2> av2(av1);
646         multi_span<int, 7, 4, 2> av2(av1);
647 #endif
648 
649         multi_span<DerivedClass> avd;
650 #ifdef CONFIRM_COMPILATION_ERRORS
651         multi_span<BaseClass> avb = avd;
652 #endif
653         multi_span<const DerivedClass> avcd = avd;
654         (void) avcd;
655     }
656 
657     TEST(copy_move_and_assignment)
658     {
659         multi_span<int> s1;
660         CHECK(s1.empty());
661 
662         int arr[] = {3, 4, 5};
663 
664         multi_span<const int> s2 = arr;
665         CHECK(s2.length() == 3 && s2.data() == &arr[0]);
666 
667         s2 = s1;
668         CHECK(s2.empty());
669 
670         auto get_temp_span = [&]() -> multi_span<int> { return {&arr[1], 2}; };
671         auto use_span = [&](multi_span<const int> s) { CHECK(s.length() == 2 && s.data() == &arr[1]); };
672         use_span(get_temp_span());
673 
674         s1 = get_temp_span();
675         CHECK(s1.length() == 2 && s1.data() == &arr[1]);
676     }
677 
678     template <class Bounds>
679     void fn(const Bounds&)
680     {
681         static_assert(Bounds::static_size == 60, "static bounds is wrong size");
682     }
683     TEST(as_multi_span_reshape)
684     {
685         int a[3][4][5];
686         auto av = as_multi_span(a);
687         fn(av.bounds());
688         auto av2 = as_multi_span(av, dim<60>());
689         auto av3 = as_multi_span(av2, dim<3>(), dim<4>(), dim<5>());
690         auto av4 = as_multi_span(av3, dim<4>(), dim(3), dim<5>());
691         auto av5 = as_multi_span(av4, dim<3>(), dim<4>(), dim<5>());
692         auto av6 = as_multi_span(av5, dim<12>(), dim(5));
693 
694         fill(av6.begin(), av6.end(), 1);
695 
696         auto av7 = as_bytes(av6);
697 
698         auto av8 = as_multi_span<int>(av7);
699 
700         CHECK(av8.size() == av6.size());
701         for (auto i = 0; i < av8.size(); i++) {
702             CHECK(av8[i] == 1);
703         }
704     }
705 
706     TEST(first)
707     {
708         int arr[5] = {1, 2, 3, 4, 5};
709 
710         {
711             multi_span<int, 5> av = arr;
712             CHECK((av.first<2>().bounds() == static_bounds<2>()));
713             CHECK(av.first<2>().length() == 2);
714             CHECK(av.first(2).length() == 2);
715         }
716 
717         {
718             multi_span<int, 5> av = arr;
719             CHECK((av.first<0>().bounds() == static_bounds<0>()));
720             CHECK(av.first<0>().length() == 0);
721             CHECK(av.first(0).length() == 0);
722         }
723 
724         {
725             multi_span<int, 5> av = arr;
726             CHECK((av.first<5>().bounds() == static_bounds<5>()));
727             CHECK(av.first<5>().length() == 5);
728             CHECK(av.first(5).length() == 5);
729         }
730 
731         {
732             multi_span<int, 5> av = arr;
733 #ifdef CONFIRM_COMPILATION_ERRORS
734             CHECK(av.first<6>().bounds() == static_bounds<6>());
735             CHECK(av.first<6>().length() == 6);
736             CHECK(av.first<-1>().length() == -1);
737 #endif
738             CHECK_THROW(av.first(6).length(), fail_fast);
739         }
740 
741         {
742             multi_span<int, dynamic_range> av;
743             CHECK((av.first<0>().bounds() == static_bounds<0>()));
744             CHECK(av.first<0>().length() == 0);
745             CHECK(av.first(0).length() == 0);
746         }
747     }
748 
749     TEST(last)
750     {
751         int arr[5] = {1, 2, 3, 4, 5};
752 
753         {
754             multi_span<int, 5> av = arr;
755             CHECK((av.last<2>().bounds() == static_bounds<2>()));
756             CHECK(av.last<2>().length() == 2);
757             CHECK(av.last(2).length() == 2);
758         }
759 
760         {
761             multi_span<int, 5> av = arr;
762             CHECK((av.last<0>().bounds() == static_bounds<0>()));
763             CHECK(av.last<0>().length() == 0);
764             CHECK(av.last(0).length() == 0);
765         }
766 
767         {
768             multi_span<int, 5> av = arr;
769             CHECK((av.last<5>().bounds() == static_bounds<5>()));
770             CHECK(av.last<5>().length() == 5);
771             CHECK(av.last(5).length() == 5);
772         }
773 
774         {
775             multi_span<int, 5> av = arr;
776 #ifdef CONFIRM_COMPILATION_ERRORS
777             CHECK((av.last<6>().bounds() == static_bounds<6>()));
778             CHECK(av.last<6>().length() == 6);
779 #endif
780             CHECK_THROW(av.last(6).length(), fail_fast);
781         }
782 
783         {
784             multi_span<int, dynamic_range> av;
785             CHECK((av.last<0>().bounds() == static_bounds<0>()));
786             CHECK(av.last<0>().length() == 0);
787             CHECK(av.last(0).length() == 0);
788         }
789     }
790 
791     TEST(subspan)
792     {
793         int arr[5] = {1, 2, 3, 4, 5};
794 
795         {
796             multi_span<int, 5> av = arr;
797             CHECK((av.subspan<2, 2>().bounds() == static_bounds<2>()));
798             CHECK((av.subspan<2, 2>().length() == 2));
799             CHECK(av.subspan(2, 2).length() == 2);
800             CHECK(av.subspan(2, 3).length() == 3);
801         }
802 
803         {
804             multi_span<int, 5> av = arr;
805             CHECK((av.subspan<0, 0>().bounds() == static_bounds<0>()));
806             CHECK((av.subspan<0, 0>().length() == 0));
807             CHECK(av.subspan(0, 0).length() == 0);
808         }
809 
810         {
811             multi_span<int, 5> av = arr;
812             CHECK((av.subspan<0, 5>().bounds() == static_bounds<5>()));
813             CHECK((av.subspan<0, 5>().length() == 5));
814             CHECK(av.subspan(0, 5).length() == 5);
815             CHECK_THROW(av.subspan(0, 6).length(), fail_fast);
816             CHECK_THROW(av.subspan(1, 5).length(), fail_fast);
817         }
818 
819         {
820             multi_span<int, 5> av = arr;
821             CHECK((av.subspan<5, 0>().bounds() == static_bounds<0>()));
822             CHECK((av.subspan<5, 0>().length() == 0));
823             CHECK(av.subspan(5, 0).length() == 0);
824             CHECK_THROW(av.subspan(6, 0).length(), fail_fast);
825         }
826 
827         {
828             multi_span<int, dynamic_range> av;
829             CHECK((av.subspan<0, 0>().bounds() == static_bounds<0>()));
830             CHECK((av.subspan<0, 0>().length() == 0));
831             CHECK(av.subspan(0, 0).length() == 0);
832             CHECK_THROW((av.subspan<1, 0>().length()), fail_fast);
833         }
834 
835         {
836             multi_span<int> av;
837             CHECK(av.subspan(0).length() == 0);
838             CHECK_THROW(av.subspan(1).length(), fail_fast);
839         }
840 
841         {
842             multi_span<int> av = arr;
843             CHECK(av.subspan(0).length() == 5);
844             CHECK(av.subspan(1).length() == 4);
845             CHECK(av.subspan(4).length() == 1);
846             CHECK(av.subspan(5).length() == 0);
847             CHECK_THROW(av.subspan(6).length(), fail_fast);
848             auto av2 = av.subspan(1);
849             for (int i = 0; i < 4; ++i) CHECK(av2[i] == i + 2);
850         }
851 
852         {
853             multi_span<int, 5> av = arr;
854             CHECK(av.subspan(0).length() == 5);
855             CHECK(av.subspan(1).length() == 4);
856             CHECK(av.subspan(4).length() == 1);
857             CHECK(av.subspan(5).length() == 0);
858             CHECK_THROW(av.subspan(6).length(), fail_fast);
859             auto av2 = av.subspan(1);
860             for (int i = 0; i < 4; ++i) CHECK(av2[i] == i + 2);
861         }
862     }
863 
864     TEST(rank)
865     {
866         int arr[2] = {1, 2};
867 
868         {
869             multi_span<int> s;
870             CHECK(s.rank() == 1);
871         }
872 
873         {
874             multi_span<int, 2> s = arr;
875             CHECK(s.rank() == 1);
876         }
877 
878         int arr2d[1][1] = {};
879         {
880             multi_span<int, 1, 1> s = arr2d;
881             CHECK(s.rank() == 2);
882         }
883     }
884 
885     TEST(extent)
886     {
887         {
888             multi_span<int> s;
889             CHECK(s.extent() == 0);
890             CHECK(s.extent(0) == 0);
891             CHECK_THROW(s.extent(1), fail_fast);
892 #ifdef CONFIRM_COMPILATION_ERRORS
893             CHECK(s.extent<1>() == 0);
894 #endif
895         }
896 
897         {
898             multi_span<int, 0> s;
899             CHECK(s.extent() == 0);
900             CHECK(s.extent(0) == 0);
901             CHECK_THROW(s.extent(1), fail_fast);
902         }
903 
904         {
905             int arr2d[1][2] = {};
906 
907             multi_span<int, 1, 2> s = arr2d;
908             CHECK(s.extent() == 1);
909             CHECK(s.extent<0>() == 1);
910             CHECK(s.extent<1>() == 2);
911             CHECK(s.extent(0) == 1);
912             CHECK(s.extent(1) == 2);
913             CHECK_THROW(s.extent(3), fail_fast);
914         }
915 
916         {
917             int arr2d[1][2] = {};
918 
919             multi_span<int, 0, 2> s = arr2d;
920             CHECK(s.extent() == 0);
921             CHECK(s.extent<0>() == 0);
922             CHECK(s.extent<1>() == 2);
923             CHECK(s.extent(0) == 0);
924             CHECK(s.extent(1) == 2);
925             CHECK_THROW(s.extent(3), fail_fast);
926         }
927     }
928 
929     TEST(operator_function_call)
930     {
931         int arr[4] = {1, 2, 3, 4};
932 
933         {
934             multi_span<int> s = arr;
935             CHECK(s(0) == 1);
936             CHECK_THROW(s(5), fail_fast);
937         }
938 
939         int arr2d[2][3] = {1, 2, 3, 4, 5, 6};
940 
941         {
942             multi_span<int, 2, 3> s = arr2d;
943             CHECK(s(0, 0) == 1);
944             CHECK(s(1, 2) == 6);
945         }
946     }
947 
948     TEST(comparison_operators)
949     {
950         {
951             int arr[10][2];
952             auto s1 = as_multi_span(arr);
953             multi_span<const int, dynamic_range, 2> s2 = s1;
954 
955             CHECK(s1 == s2);
956 
957             multi_span<int, 20> s3 = as_multi_span(s1, dim(20));
958             CHECK(s3 == s2 && s3 == s1);
959         }
960 
961         {
962             multi_span<int> s1 = nullptr;
963             multi_span<int> s2 = nullptr;
964             CHECK(s1 == s2);
965             CHECK(!(s1 != s2));
966             CHECK(!(s1 < s2));
967             CHECK(s1 <= s2);
968             CHECK(!(s1 > s2));
969             CHECK(s1 >= s2);
970             CHECK(s2 == s1);
971             CHECK(!(s2 != s1));
972             CHECK(!(s2 < s1));
973             CHECK(s2 <= s1);
974             CHECK(!(s2 > s1));
975             CHECK(s2 >= s1);
976         }
977 
978         {
979             int arr[] = {2, 1}; // bigger
980 
981             multi_span<int> s1 = nullptr;
982             multi_span<int> s2 = arr;
983 
984             CHECK(s1 != s2);
985             CHECK(s2 != s1);
986             CHECK(!(s1 == s2));
987             CHECK(!(s2 == s1));
988             CHECK(s1 < s2);
989             CHECK(!(s2 < s1));
990             CHECK(s1 <= s2);
991             CHECK(!(s2 <= s1));
992             CHECK(s2 > s1);
993             CHECK(!(s1 > s2));
994             CHECK(s2 >= s1);
995             CHECK(!(s1 >= s2));
996         }
997 
998         {
999             int arr1[] = {1, 2};
1000             int arr2[] = {1, 2};
1001             multi_span<int> s1 = arr1;
1002             multi_span<int> s2 = arr2;
1003 
1004             CHECK(s1 == s2);
1005             CHECK(!(s1 != s2));
1006             CHECK(!(s1 < s2));
1007             CHECK(s1 <= s2);
1008             CHECK(!(s1 > s2));
1009             CHECK(s1 >= s2);
1010             CHECK(s2 == s1);
1011             CHECK(!(s2 != s1));
1012             CHECK(!(s2 < s1));
1013             CHECK(s2 <= s1);
1014             CHECK(!(s2 > s1));
1015             CHECK(s2 >= s1);
1016         }
1017 
1018         {
1019             int arr[] = {1, 2, 3};
1020 
1021             multi_span<int> s1 = {&arr[0], 2}; // shorter
1022             multi_span<int> s2 = arr; // longer
1023 
1024             CHECK(s1 != s2);
1025             CHECK(s2 != s1);
1026             CHECK(!(s1 == s2));
1027             CHECK(!(s2 == s1));
1028             CHECK(s1 < s2);
1029             CHECK(!(s2 < s1));
1030             CHECK(s1 <= s2);
1031             CHECK(!(s2 <= s1));
1032             CHECK(s2 > s1);
1033             CHECK(!(s1 > s2));
1034             CHECK(s2 >= s1);
1035             CHECK(!(s1 >= s2));
1036         }
1037 
1038         {
1039             int arr1[] = {1, 2}; // smaller
1040             int arr2[] = {2, 1}; // bigger
1041 
1042             multi_span<int> s1 = arr1;
1043             multi_span<int> s2 = arr2;
1044 
1045             CHECK(s1 != s2);
1046             CHECK(s2 != s1);
1047             CHECK(!(s1 == s2));
1048             CHECK(!(s2 == s1));
1049             CHECK(s1 < s2);
1050             CHECK(!(s2 < s1));
1051             CHECK(s1 <= s2);
1052             CHECK(!(s2 <= s1));
1053             CHECK(s2 > s1);
1054             CHECK(!(s1 > s2));
1055             CHECK(s2 >= s1);
1056             CHECK(!(s1 >= s2));
1057         }
1058     }
1059 
1060     TEST(basics)
1061     {
1062         auto ptr = as_multi_span(new int[10], 10);
1063         fill(ptr.begin(), ptr.end(), 99);
1064         for (int num : ptr) {
1065             CHECK(num == 99);
1066         }
1067 
1068         delete[] ptr.data();
1069     }
1070 
1071     TEST(bounds_checks)
1072     {
1073         int arr[10][2];
1074         auto av = as_multi_span(arr);
1075 
1076         fill(begin(av), end(av), 0);
1077 
1078         av[2][0] = 1;
1079         av[1][1] = 3;
1080 
1081         // out of bounds
1082         CHECK_THROW(av[1][3] = 3, fail_fast);
1083         CHECK_THROW((av[{1, 3}] = 3), fail_fast);
1084 
1085         CHECK_THROW(av[10][2], fail_fast);
1086         CHECK_THROW((av[{10, 2}]), fail_fast);
1087 
1088         CHECK_THROW(av[-1][0], fail_fast);
1089         CHECK_THROW((av[{-1, 0}]), fail_fast);
1090 
1091         CHECK_THROW(av[0][-1], fail_fast);
1092         CHECK_THROW((av[{0, -1}]), fail_fast);
1093     }
1094 
1095     void overloaded_func(multi_span<const int, dynamic_range, 3, 5> exp, int expected_value)
1096     {
1097         for (auto val : exp) {
1098             CHECK(val == expected_value);
1099         }
1100     }
1101 
1102     void overloaded_func(multi_span<const char, dynamic_range, 3, 5> exp, char expected_value)
1103     {
1104         for (auto val : exp) {
1105             CHECK(val == expected_value);
1106         }
1107     }
1108 
1109     void fixed_func(multi_span<int, 3, 3, 5> exp, int expected_value)
1110     {
1111         for (auto val : exp) {
1112             CHECK(val == expected_value);
1113         }
1114     }
1115 
1116     TEST(span_parameter_test)
1117     {
1118         auto data = new int[4][3][5];
1119 
1120         auto av = as_multi_span(data, 4);
1121 
1122         CHECK(av.size() == 60);
1123 
1124         fill(av.begin(), av.end(), 34);
1125 
1126         int count = 0;
1127         for_each(av.rbegin(), av.rend(), [&](int val) { count += val; });
1128         CHECK(count == 34 * 60);
1129         overloaded_func(av, 34);
1130 
1131         overloaded_func(as_multi_span(av, dim(4), dim(3), dim(5)), 34);
1132 
1133         // fixed_func(av, 34);
1134         delete[] data;
1135     }
1136 
1137     TEST(md_access)
1138     {
1139         auto width = 5, height = 20;
1140 
1141         auto imgSize = width * height;
1142         auto image_ptr = new int[imgSize][3];
1143 
1144         // size check will be done
1145         auto image_view =
1146             as_multi_span(as_multi_span(image_ptr, imgSize), dim(height), dim(width), dim<3>());
1147 
1148         iota(image_view.begin(), image_view.end(), 1);
1149 
1150         int expected = 0;
1151         for (auto i = 0; i < height; i++) {
1152             for (auto j = 0; j < width; j++) {
1153                 CHECK(expected + 1 == image_view[i][j][0]);
1154                 CHECK(expected + 2 == image_view[i][j][1]);
1155                 CHECK(expected + 3 == image_view[i][j][2]);
1156 
1157                 auto val = image_view[{i, j, 0}];
1158                 CHECK(expected + 1 == val);
1159                 val = image_view[{i, j, 1}];
1160                 CHECK(expected + 2 == val);
1161                 val = image_view[{i, j, 2}];
1162                 CHECK(expected + 3 == val);
1163 
1164                 expected += 3;
1165             }
1166         }
1167     }
1168 
1169     TEST(as_multi_span)
1170     {
1171         {
1172             int* arr = new int[150];
1173 
1174             auto av = as_multi_span(arr, dim<10>(), dim(3), dim<5>());
1175 
1176             fill(av.begin(), av.end(), 24);
1177             overloaded_func(av, 24);
1178 
1179             delete[] arr;
1180 
1181             array<int, 15> stdarr{0};
1182             auto av2 = as_multi_span(stdarr);
1183             overloaded_func(as_multi_span(av2, dim(1), dim<3>(), dim<5>()), 0);
1184 
1185             string str = "ttttttttttttttt"; // size = 15
1186             auto t = str.data();
1187             (void) t;
1188             auto av3 = as_multi_span(str);
1189             overloaded_func(as_multi_span(av3, dim(1), dim<3>(), dim<5>()), 't');
1190         }
1191 
1192         {
1193             string str;
1194             multi_span<char> strspan = as_multi_span(str);
1195             (void) strspan;
1196             const string cstr;
1197             multi_span<const char> cstrspan = as_multi_span(cstr);
1198             (void) cstrspan;
1199         }
1200 
1201         {
1202             int a[3][4][5];
1203             auto av = as_multi_span(a);
1204             const int(*b)[4][5];
1205             b = a;
1206             auto bv = as_multi_span(b, 3);
1207 
1208             CHECK(av == bv);
1209 
1210             const std::array<double, 3> arr = {0.0, 0.0, 0.0};
1211             auto cv = as_multi_span(arr);
1212             (void) cv;
1213 
1214             vector<float> vec(3);
1215             auto dv = as_multi_span(vec);
1216             (void) dv;
1217 
1218 #ifdef CONFIRM_COMPILATION_ERRORS
1219             auto dv2 = as_multi_span(std::move(vec));
1220 #endif
1221         }
1222     }
1223 
1224     TEST(empty_spans)
1225     {
1226         {
1227             multi_span<int, 0> empty_av(nullptr);
1228 
1229             CHECK(empty_av.bounds().index_bounds() == index<1>{0});
1230             CHECK_THROW(empty_av[0], fail_fast);
1231             CHECK_THROW(empty_av.begin()[0], fail_fast);
1232             CHECK_THROW(empty_av.cbegin()[0], fail_fast);
1233             for (auto& v : empty_av) {
1234                 (void) v;
1235                 CHECK(false);
1236             }
1237         }
1238 
1239         {
1240             multi_span<int> empty_av = {};
1241             CHECK(empty_av.bounds().index_bounds() == index<1>{0});
1242             CHECK_THROW(empty_av[0], fail_fast);
1243             CHECK_THROW(empty_av.begin()[0], fail_fast);
1244             CHECK_THROW(empty_av.cbegin()[0], fail_fast);
1245             for (auto& v : empty_av) {
1246                 (void) v;
1247                 CHECK(false);
1248             }
1249         }
1250     }
1251 
1252     TEST(index_constructor)
1253     {
1254         auto arr = new int[8];
1255         for (int i = 0; i < 4; ++i) {
1256             arr[2 * i] = 4 + i;
1257             arr[2 * i + 1] = i;
1258         }
1259 
1260         multi_span<int, dynamic_range> av(arr, 8);
1261 
1262         ptrdiff_t a[1] = {0};
1263         index<1> i = a;
1264 
1265         CHECK(av[i] == 4);
1266 
1267         auto av2 = as_multi_span(av, dim<4>(), dim(2));
1268         ptrdiff_t a2[2] = {0, 1};
1269         index<2> i2 = a2;
1270 
1271         CHECK(av2[i2] == 0);
1272         CHECK(av2[0][i] == 4);
1273 
1274         delete[] arr;
1275     }
1276 
1277     TEST(index_constructors)
1278     {
1279         {
1280             // components of the same type
1281             index<3> i1(0, 1, 2);
1282             CHECK(i1[0] == 0);
1283 
1284             // components of different types
1285             size_t c0 = 0;
1286             size_t c1 = 1;
1287             index<3> i2(c0, c1, 2);
1288             CHECK(i2[0] == 0);
1289 
1290             // from array
1291             index<3> i3 = {0, 1, 2};
1292             CHECK(i3[0] == 0);
1293 
1294             // from other index of the same size type
1295             index<3> i4 = i3;
1296             CHECK(i4[0] == 0);
1297 
1298             // default
1299             index<3> i7;
1300             CHECK(i7[0] == 0);
1301 
1302             // default
1303             index<3> i9 = {};
1304             CHECK(i9[0] == 0);
1305         }
1306 
1307         {
1308             // components of the same type
1309             index<1> i1(0);
1310             CHECK(i1[0] == 0);
1311 
1312             // components of different types
1313             size_t c0 = 0;
1314             index<1> i2(c0);
1315             CHECK(i2[0] == 0);
1316 
1317             // from array
1318             index<1> i3 = {0};
1319             CHECK(i3[0] == 0);
1320 
1321             // from int
1322             index<1> i4 = 0;
1323             CHECK(i4[0] == 0);
1324 
1325             // from other index of the same size type
1326             index<1> i5 = i3;
1327             CHECK(i5[0] == 0);
1328 
1329             // default
1330             index<1> i8;
1331             CHECK(i8[0] == 0);
1332 
1333             // default
1334             index<1> i9 = {};
1335             CHECK(i9[0] == 0);
1336         }
1337 
1338 #ifdef CONFIRM_COMPILATION_ERRORS
1339         {
1340             index<3> i1(0, 1);
1341             index<3> i2(0, 1, 2, 3);
1342             index<3> i3 = {0};
1343             index<3> i4 = {0, 1, 2, 3};
1344             index<1> i5 = {0, 1};
1345         }
1346 #endif
1347     }
1348 
1349     TEST(index_operations)
1350     {
1351         ptrdiff_t a[3] = {0, 1, 2};
1352         ptrdiff_t b[3] = {3, 4, 5};
1353         index<3> i = a;
1354         index<3> j = b;
1355 
1356         CHECK(i[0] == 0);
1357         CHECK(i[1] == 1);
1358         CHECK(i[2] == 2);
1359 
1360         {
1361             index<3> k = i + j;
1362 
1363             CHECK(i[0] == 0);
1364             CHECK(i[1] == 1);
1365             CHECK(i[2] == 2);
1366             CHECK(k[0] == 3);
1367             CHECK(k[1] == 5);
1368             CHECK(k[2] == 7);
1369         }
1370 
1371         {
1372             index<3> k = i * 3;
1373 
1374             CHECK(i[0] == 0);
1375             CHECK(i[1] == 1);
1376             CHECK(i[2] == 2);
1377             CHECK(k[0] == 0);
1378             CHECK(k[1] == 3);
1379             CHECK(k[2] == 6);
1380         }
1381 
1382         {
1383             index<3> k = 3 * i;
1384 
1385             CHECK(i[0] == 0);
1386             CHECK(i[1] == 1);
1387             CHECK(i[2] == 2);
1388             CHECK(k[0] == 0);
1389             CHECK(k[1] == 3);
1390             CHECK(k[2] == 6);
1391         }
1392 
1393         {
1394             index<2> k = details::shift_left(i);
1395 
1396             CHECK(i[0] == 0);
1397             CHECK(i[1] == 1);
1398             CHECK(i[2] == 2);
1399             CHECK(k[0] == 1);
1400             CHECK(k[1] == 2);
1401         }
1402     }
1403 
1404     void iterate_second_column(multi_span<int, dynamic_range, dynamic_range> av)
1405     {
1406         auto length = av.size() / 2;
1407 
1408         // view to the second column
1409         auto section = av.section({0, 1}, {length, 1});
1410 
1411         CHECK(section.size() == length);
1412         for (auto i = 0; i < section.size(); ++i) {
1413             CHECK(section[i][0] == av[i][1]);
1414         }
1415 
1416         for (auto i = 0; i < section.size(); ++i) {
1417             auto idx = index<2>{i, 0}; // avoid braces inside the CHECK macro
1418             CHECK(section[idx] == av[i][1]);
1419         }
1420 
1421         CHECK(section.bounds().index_bounds()[0] == length);
1422         CHECK(section.bounds().index_bounds()[1] == 1);
1423         for (auto i = 0; i < section.bounds().index_bounds()[0]; ++i) {
1424             for (auto j = 0; j < section.bounds().index_bounds()[1]; ++j) {
1425                 auto idx = index<2>{i, j}; // avoid braces inside the CHECK macro
1426                 CHECK(section[idx] == av[i][1]);
1427             }
1428         }
1429 
1430         size_t check_sum = 0;
1431         for (auto i = 0; i < length; ++i) {
1432             check_sum += av[i][1];
1433         }
1434 
1435         {
1436             auto idx = 0;
1437             size_t sum = 0;
1438             for (auto num : section) {
1439                 CHECK(num == av[idx][1]);
1440                 sum += num;
1441                 idx++;
1442             }
1443 
1444             CHECK(sum == check_sum);
1445         }
1446         {
1447             size_t idx = length - 1;
1448             size_t sum = 0;
1449             for (auto iter = section.rbegin(); iter != section.rend(); ++iter) {
1450                 CHECK(*iter == av[idx][1]);
1451                 sum += *iter;
1452                 idx--;
1453             }
1454 
1455             CHECK(sum == check_sum);
1456         }
1457     }
1458 
1459     TEST(span_section_iteration)
1460     {
1461         int arr[4][2] = {{4, 0}, {5, 1}, {6, 2}, {7, 3}};
1462 
1463         // static bounds
1464         {
1465             multi_span<int, 4, 2> av = arr;
1466             iterate_second_column(av);
1467         }
1468         // first bound is dynamic
1469         {
1470             multi_span<int, dynamic_range, 2> av = arr;
1471             iterate_second_column(av);
1472         }
1473         // second bound is dynamic
1474         {
1475             multi_span<int, 4, dynamic_range> av = arr;
1476             iterate_second_column(av);
1477         }
1478         // both bounds are dynamic
1479         {
1480             multi_span<int, dynamic_range, dynamic_range> av = arr;
1481             iterate_second_column(av);
1482         }
1483     }
1484 
1485     TEST(dynamic_span_section_iteration)
1486     {
1487         auto height = 4, width = 2;
1488         auto size = height * width;
1489 
1490         auto arr = new int[size];
1491         for (auto i = 0; i < size; ++i) {
1492             arr[i] = i;
1493         }
1494 
1495         auto av = as_multi_span(arr, size);
1496 
1497         // first bound is dynamic
1498         {
1499             multi_span<int, dynamic_range, 2> av2 = as_multi_span(av, dim(height), dim(width));
1500             iterate_second_column(av2);
1501         }
1502         // second bound is dynamic
1503         {
1504             multi_span<int, 4, dynamic_range> av2 = as_multi_span(av, dim(height), dim(width));
1505             iterate_second_column(av2);
1506         }
1507         // both bounds are dynamic
1508         {
1509             multi_span<int, dynamic_range, dynamic_range> av2 = as_multi_span(av, dim(height), dim(width));
1510             iterate_second_column(av2);
1511         }
1512 
1513         delete[] arr;
1514     }
1515 
1516     TEST(span_structure_size)
1517     {
1518         double(*arr)[3][4] = new double[100][3][4];
1519         multi_span<double, dynamic_range, 3, 4> av1(arr, 10);
1520 
1521         struct EffectiveStructure
1522         {
1523             double* v1;
1524             ptrdiff_t v2;
1525         };
1526         CHECK(sizeof(av1) == sizeof(EffectiveStructure));
1527 
1528         CHECK_THROW(av1[10][3][4], fail_fast);
1529 
1530         multi_span<const double, dynamic_range, 6, 4> av2 = as_multi_span(av1, dim(5), dim<6>(), dim<4>());
1531         (void) av2;
1532     }
1533 
1534     TEST(fixed_size_conversions)
1535     {
1536         int arr[] = {1, 2, 3, 4};
1537 
1538         // converting to an multi_span from an equal size array is ok
1539         multi_span<int, 4> av4 = arr;
1540         CHECK(av4.length() == 4);
1541 
1542         // converting to dynamic_range a_v is always ok
1543         {
1544             multi_span<int, dynamic_range> av = av4;
1545             (void) av;
1546         }
1547         {
1548             multi_span<int, dynamic_range> av = arr;
1549             (void) av;
1550         }
1551 
1552 // initialization or assignment to static multi_span that REDUCES size is NOT ok
1553 #ifdef CONFIRM_COMPILATION_ERRORS
1554         {
1555             multi_span<int, 2> av2 = arr;
1556         }
1557         {
1558             multi_span<int, 2> av2 = av4;
1559         }
1560 #endif
1561 
1562         {
1563             multi_span<int, dynamic_range> av = arr;
1564             multi_span<int, 2> av2 = av;
1565             (void) av2;
1566         }
1567 
1568 #ifdef CONFIRM_COMPILATION_ERRORS
1569         {
1570             multi_span<int, dynamic_range> av = arr;
1571             multi_span<int, 2, 1> av2 = av.as_multi_span(dim<2>(), dim<2>());
1572         }
1573 #endif
1574 
1575         {
1576             multi_span<int, dynamic_range> av = arr;
1577             multi_span<int, 2, 1> av2 = as_multi_span(av, dim(2), dim(2));
1578             auto workaround_macro = [&]() { return av2[{1, 0}] == 2; };
1579             CHECK(workaround_macro());
1580         }
1581 
1582         // but doing so explicitly is ok
1583 
1584         // you can convert statically
1585         {
1586             multi_span<int, 2> av2 = {arr, 2};
1587             (void) av2;
1588         }
1589         {
1590             multi_span<int, 1> av2 = av4.first<1>();
1591             (void) av2;
1592         }
1593 
1594         // ...or dynamically
1595         {
1596             // NB: implicit conversion to multi_span<int,2> from multi_span<int,dynamic_range>
1597             multi_span<int, 1> av2 = av4.first(1);
1598             (void) av2;
1599         }
1600 
1601         // initialization or assignment to static multi_span that requires size INCREASE is not ok.
1602         int arr2[2] = {1, 2};
1603 
1604 #ifdef CONFIRM_COMPILATION_ERRORS
1605         {
1606             multi_span<int, 4> av4 = arr2;
1607         }
1608         {
1609             multi_span<int, 2> av2 = arr2;
1610             multi_span<int, 4> av4 = av2;
1611         }
1612 #endif
1613         {
1614             auto f = [&]() {
1615                 multi_span<int, 4> av9 = {arr2, 2};
1616                 (void) av9;
1617             };
1618             CHECK_THROW(f(), fail_fast);
1619         }
1620 
1621         // this should fail - we are trying to assign a small dynamic a_v to a fixed_size larger one
1622         multi_span<int, dynamic_range> av = arr2;
1623         auto f = [&]() {
1624             multi_span<int, 4> av2 = av;
1625             (void) av2;
1626         };
1627         CHECK_THROW(f(), fail_fast);
1628     }
1629 
1630     TEST(as_writeable_bytes)
1631     {
1632         int a[] = {1, 2, 3, 4};
1633 
1634         {
1635 #ifdef CONFIRM_COMPILATION_ERRORS
1636             // you should not be able to get writeable bytes for const objects
1637             multi_span<const int, dynamic_range> av = a;
1638             auto wav = av.as_writeable_bytes();
1639 #endif
1640         }
1641 
1642         {
1643             multi_span<int, dynamic_range> av;
1644             auto wav = as_writeable_bytes(av);
1645             CHECK(wav.length() == av.length());
1646             CHECK(wav.length() == 0);
1647             CHECK(wav.size_bytes() == 0);
1648         }
1649 
1650         {
1651             multi_span<int, dynamic_range> av = a;
1652             auto wav = as_writeable_bytes(av);
1653             CHECK(wav.data() == (byte*) &a[0]);
1654             CHECK(wav.length() == sizeof(a));
1655         }
1656     }
1657 
1658     TEST(iterator)
1659     {
1660         int a[] = {1, 2, 3, 4};
1661 
1662         {
1663             multi_span<int, dynamic_range> av = a;
1664             auto wav = as_writeable_bytes(av);
1665             for (auto& b : wav) {
1666                 b = byte(0);
1667             }
1668             for (size_t i = 0; i < 4; ++i) {
1669                 CHECK(a[i] == 0);
1670             }
1671         }
1672 
1673         {
1674             multi_span<int, dynamic_range> av = a;
1675             for (auto& n : av) {
1676                 n = 1;
1677             }
1678             for (size_t i = 0; i < 4; ++i) {
1679                 CHECK(a[i] == 1);
1680             }
1681         }
1682     }
1683 }
1684 
main(int,const char * [])1685 int main(int, const char* []) { return UnitTest::RunAllTests(); }
1686