xref: /freebsd/contrib/llvm-project/libcxx/include/__pstl/backends/default.h (revision 0fca6ea1d4eea4c934cfff25ac9ee8ad6fe95583)
1 //===----------------------------------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #ifndef _LIBCPP___PSTL_BACKENDS_DEFAULT_H
10 #define _LIBCPP___PSTL_BACKENDS_DEFAULT_H
11 
12 #include <__algorithm/copy_n.h>
13 #include <__algorithm/equal.h>
14 #include <__algorithm/fill_n.h>
15 #include <__algorithm/for_each_n.h>
16 #include <__config>
17 #include <__functional/identity.h>
18 #include <__functional/not_fn.h>
19 #include <__functional/operations.h>
20 #include <__iterator/concepts.h>
21 #include <__iterator/iterator_traits.h>
22 #include <__pstl/backend_fwd.h>
23 #include <__pstl/dispatch.h>
24 #include <__utility/empty.h>
25 #include <__utility/forward.h>
26 #include <__utility/move.h>
27 #include <optional>
28 
29 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
30 #  pragma GCC system_header
31 #endif
32 
33 _LIBCPP_PUSH_MACROS
34 #include <__undef_macros>
35 
36 _LIBCPP_BEGIN_NAMESPACE_STD
37 namespace __pstl {
38 
39 //
40 // This file provides an incomplete PSTL backend that implements all of the PSTL algorithms
41 // based on a smaller set of basis operations.
42 //
43 // It is intended as a building block for other PSTL backends that implement some operations more
44 // efficiently but may not want to define the full set of PSTL algorithms.
45 //
46 // This backend implements all the PSTL algorithms based on the following basis operations:
47 //
48 // find_if family
49 // --------------
50 // - find
51 // - find_if_not
52 // - any_of
53 // - all_of
54 // - none_of
55 // - is_partitioned
56 //
57 // for_each family
58 // ---------------
59 // - for_each_n
60 // - fill
61 // - fill_n
62 // - replace
63 // - replace_if
64 // - generate
65 // - generate_n
66 //
67 // merge family
68 // ------------
69 // No other algorithms based on merge
70 //
71 // stable_sort family
72 // ------------------
73 // - sort
74 //
75 // transform_reduce and transform_reduce_binary family
76 // ---------------------------------------------------
77 // - count_if
78 // - count
79 // - equal(3 legs)
80 // - equal
81 // - reduce
82 //
83 // transform and transform_binary family
84 // -------------------------------------
85 // - replace_copy_if
86 // - replace_copy
87 // - move
88 // - copy
89 // - copy_n
90 // - rotate_copy
91 //
92 
93 //////////////////////////////////////////////////////////////
94 // find_if family
95 //////////////////////////////////////////////////////////////
96 template <class _ExecutionPolicy>
97 struct __find<__default_backend_tag, _ExecutionPolicy> {
98   template <class _Policy, class _ForwardIterator, class _Tp>
99   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI optional<_ForwardIterator>
100   operator()(_Policy&& __policy, _ForwardIterator __first, _ForwardIterator __last, const _Tp& __value) const noexcept {
101     using _FindIf = __dispatch<__find_if, __current_configuration, _ExecutionPolicy>;
102     return _FindIf()(
103         __policy, std::move(__first), std::move(__last), [&](__iter_reference<_ForwardIterator> __element) {
104           return __element == __value;
105         });
106   }
107 };
108 
109 template <class _ExecutionPolicy>
110 struct __find_if_not<__default_backend_tag, _ExecutionPolicy> {
111   template <class _Policy, class _ForwardIterator, class _Pred>
112   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI optional<_ForwardIterator>
113   operator()(_Policy&& __policy, _ForwardIterator __first, _ForwardIterator __last, _Pred&& __pred) const noexcept {
114     using _FindIf = __dispatch<__find_if, __current_configuration, _ExecutionPolicy>;
115     return _FindIf()(__policy, __first, __last, std::not_fn(std::forward<_Pred>(__pred)));
116   }
117 };
118 
119 template <class _ExecutionPolicy>
120 struct __any_of<__default_backend_tag, _ExecutionPolicy> {
121   template <class _Policy, class _ForwardIterator, class _Pred>
122   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI optional<bool>
123   operator()(_Policy&& __policy, _ForwardIterator __first, _ForwardIterator __last, _Pred&& __pred) const noexcept {
124     using _FindIf = __dispatch<__find_if, __current_configuration, _ExecutionPolicy>;
125     auto __res    = _FindIf()(__policy, __first, __last, std::forward<_Pred>(__pred));
126     if (!__res)
127       return nullopt;
128     return *__res != __last;
129   }
130 };
131 
132 template <class _ExecutionPolicy>
133 struct __all_of<__default_backend_tag, _ExecutionPolicy> {
134   template <class _Policy, class _ForwardIterator, class _Pred>
135   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI optional<bool>
136   operator()(_Policy&& __policy, _ForwardIterator __first, _ForwardIterator __last, _Pred&& __pred) const noexcept {
137     using _AnyOf = __dispatch<__any_of, __current_configuration, _ExecutionPolicy>;
138     auto __res   = _AnyOf()(__policy, __first, __last, [&](__iter_reference<_ForwardIterator> __value) {
139       return !__pred(__value);
140     });
141     if (!__res)
142       return nullopt;
143     return !*__res;
144   }
145 };
146 
147 template <class _ExecutionPolicy>
148 struct __none_of<__default_backend_tag, _ExecutionPolicy> {
149   template <class _Policy, class _ForwardIterator, class _Pred>
150   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI optional<bool>
151   operator()(_Policy&& __policy, _ForwardIterator __first, _ForwardIterator __last, _Pred&& __pred) const noexcept {
152     using _AnyOf = __dispatch<__any_of, __current_configuration, _ExecutionPolicy>;
153     auto __res   = _AnyOf()(__policy, __first, __last, std::forward<_Pred>(__pred));
154     if (!__res)
155       return nullopt;
156     return !*__res;
157   }
158 };
159 
160 template <class _ExecutionPolicy>
161 struct __is_partitioned<__default_backend_tag, _ExecutionPolicy> {
162   template <class _Policy, class _ForwardIterator, class _Pred>
163   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI optional<bool>
164   operator()(_Policy&& __policy, _ForwardIterator __first, _ForwardIterator __last, _Pred&& __pred) const noexcept {
165     using _FindIfNot   = __dispatch<__find_if_not, __current_configuration, _ExecutionPolicy>;
166     auto __maybe_first = _FindIfNot()(__policy, std::move(__first), std::move(__last), __pred);
167     if (__maybe_first == nullopt)
168       return nullopt;
169 
170     __first = *__maybe_first;
171     if (__first == __last)
172       return true;
173     ++__first;
174     using _NoneOf = __dispatch<__none_of, __current_configuration, _ExecutionPolicy>;
175     return _NoneOf()(__policy, std::move(__first), std::move(__last), __pred);
176   }
177 };
178 
179 //////////////////////////////////////////////////////////////
180 // for_each family
181 //////////////////////////////////////////////////////////////
182 template <class _ExecutionPolicy>
183 struct __for_each_n<__default_backend_tag, _ExecutionPolicy> {
184   template <class _Policy, class _ForwardIterator, class _Size, class _Function>
185   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI optional<__empty>
186   operator()(_Policy&& __policy, _ForwardIterator __first, _Size __size, _Function __func) const noexcept {
187     if constexpr (__has_random_access_iterator_category_or_concept<_ForwardIterator>::value) {
188       using _ForEach          = __dispatch<__for_each, __current_configuration, _ExecutionPolicy>;
189       _ForwardIterator __last = __first + __size;
190       return _ForEach()(__policy, std::move(__first), std::move(__last), std::move(__func));
191     } else {
192       // Otherwise, use the serial algorithm to avoid doing two passes over the input
193       std::for_each_n(std::move(__first), __size, std::move(__func));
194       return __empty{};
195     }
196   }
197 };
198 
199 template <class _ExecutionPolicy>
200 struct __fill<__default_backend_tag, _ExecutionPolicy> {
201   template <class _Policy, class _ForwardIterator, class _Tp>
202   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI optional<__empty>
203   operator()(_Policy&& __policy, _ForwardIterator __first, _ForwardIterator __last, _Tp const& __value) const noexcept {
204     using _ForEach = __dispatch<__for_each, __current_configuration, _ExecutionPolicy>;
205     using _Ref     = __iter_reference<_ForwardIterator>;
206     return _ForEach()(__policy, std::move(__first), std::move(__last), [&](_Ref __element) { __element = __value; });
207   }
208 };
209 
210 template <class _ExecutionPolicy>
211 struct __fill_n<__default_backend_tag, _ExecutionPolicy> {
212   template <class _Policy, class _ForwardIterator, class _Size, class _Tp>
213   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI optional<__empty>
214   operator()(_Policy&& __policy, _ForwardIterator __first, _Size __n, _Tp const& __value) const noexcept {
215     if constexpr (__has_random_access_iterator_category_or_concept<_ForwardIterator>::value) {
216       using _Fill             = __dispatch<__fill, __current_configuration, _ExecutionPolicy>;
217       _ForwardIterator __last = __first + __n;
218       return _Fill()(__policy, std::move(__first), std::move(__last), __value);
219     } else {
220       // Otherwise, use the serial algorithm to avoid doing two passes over the input
221       std::fill_n(std::move(__first), __n, __value);
222       return optional<__empty>{__empty{}};
223     }
224   }
225 };
226 
227 template <class _ExecutionPolicy>
228 struct __replace<__default_backend_tag, _ExecutionPolicy> {
229   template <class _Policy, class _ForwardIterator, class _Tp>
230   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI optional<__empty>
231   operator()(_Policy&& __policy, _ForwardIterator __first, _ForwardIterator __last, _Tp const& __old, _Tp const& __new)
232       const noexcept {
233     using _ReplaceIf = __dispatch<__replace_if, __current_configuration, _ExecutionPolicy>;
234     using _Ref       = __iter_reference<_ForwardIterator>;
235     return _ReplaceIf()(
236         __policy, std::move(__first), std::move(__last), [&](_Ref __element) { return __element == __old; }, __new);
237   }
238 };
239 
240 template <class _ExecutionPolicy>
241 struct __replace_if<__default_backend_tag, _ExecutionPolicy> {
242   template <class _Policy, class _ForwardIterator, class _Pred, class _Tp>
243   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI optional<__empty> operator()(
244       _Policy&& __policy, _ForwardIterator __first, _ForwardIterator __last, _Pred&& __pred, _Tp const& __new_value)
245       const noexcept {
246     using _ForEach = __dispatch<__for_each, __current_configuration, _ExecutionPolicy>;
247     using _Ref     = __iter_reference<_ForwardIterator>;
248     return _ForEach()(__policy, std::move(__first), std::move(__last), [&](_Ref __element) {
249       if (__pred(__element))
250         __element = __new_value;
251     });
252   }
253 };
254 
255 template <class _ExecutionPolicy>
256 struct __generate<__default_backend_tag, _ExecutionPolicy> {
257   template <class _Policy, class _ForwardIterator, class _Generator>
258   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI optional<__empty>
259   operator()(_Policy&& __policy, _ForwardIterator __first, _ForwardIterator __last, _Generator&& __gen) const noexcept {
260     using _ForEach = __dispatch<__for_each, __current_configuration, _ExecutionPolicy>;
261     using _Ref     = __iter_reference<_ForwardIterator>;
262     return _ForEach()(__policy, std::move(__first), std::move(__last), [&](_Ref __element) { __element = __gen(); });
263   }
264 };
265 
266 template <class _ExecutionPolicy>
267 struct __generate_n<__default_backend_tag, _ExecutionPolicy> {
268   template <class _Policy, class _ForwardIterator, class _Size, class _Generator>
269   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI optional<__empty>
270   operator()(_Policy&& __policy, _ForwardIterator __first, _Size __n, _Generator&& __gen) const noexcept {
271     using _ForEachN = __dispatch<__for_each_n, __current_configuration, _ExecutionPolicy>;
272     using _Ref      = __iter_reference<_ForwardIterator>;
273     return _ForEachN()(__policy, std::move(__first), __n, [&](_Ref __element) { __element = __gen(); });
274   }
275 };
276 
277 //////////////////////////////////////////////////////////////
278 // stable_sort family
279 //////////////////////////////////////////////////////////////
280 template <class _ExecutionPolicy>
281 struct __sort<__default_backend_tag, _ExecutionPolicy> {
282   template <class _Policy, class _RandomAccessIterator, class _Comp>
283   _LIBCPP_HIDE_FROM_ABI optional<__empty> operator()(
284       _Policy&& __policy, _RandomAccessIterator __first, _RandomAccessIterator __last, _Comp&& __comp) const noexcept {
285     using _StableSort = __dispatch<__stable_sort, __current_configuration, _ExecutionPolicy>;
286     return _StableSort()(__policy, std::move(__first), std::move(__last), std::forward<_Comp>(__comp));
287   }
288 };
289 
290 //////////////////////////////////////////////////////////////
291 // transform_reduce family
292 //////////////////////////////////////////////////////////////
293 template <class _ExecutionPolicy>
294 struct __count_if<__default_backend_tag, _ExecutionPolicy> {
295   template <class _Policy, class _ForwardIterator, class _Predicate>
296   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI optional<__iter_diff_t<_ForwardIterator>> operator()(
297       _Policy&& __policy, _ForwardIterator __first, _ForwardIterator __last, _Predicate&& __pred) const noexcept {
298     using _TransformReduce = __dispatch<__transform_reduce, __current_configuration, _ExecutionPolicy>;
299     using _DiffT           = __iter_diff_t<_ForwardIterator>;
300     using _Ref             = __iter_reference<_ForwardIterator>;
301     return _TransformReduce()(
302         __policy, std::move(__first), std::move(__last), _DiffT{}, std::plus{}, [&](_Ref __element) -> _DiffT {
303           return __pred(__element) ? _DiffT(1) : _DiffT(0);
304         });
305   }
306 };
307 
308 template <class _ExecutionPolicy>
309 struct __count<__default_backend_tag, _ExecutionPolicy> {
310   template <class _Policy, class _ForwardIterator, class _Tp>
311   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI optional<__iter_diff_t<_ForwardIterator>>
312   operator()(_Policy&& __policy, _ForwardIterator __first, _ForwardIterator __last, _Tp const& __value) const noexcept {
313     using _CountIf = __dispatch<__count_if, __current_configuration, _ExecutionPolicy>;
314     using _Ref     = __iter_reference<_ForwardIterator>;
315     return _CountIf()(__policy, std::move(__first), std::move(__last), [&](_Ref __element) -> bool {
316       return __element == __value;
317     });
318   }
319 };
320 
321 template <class _ExecutionPolicy>
322 struct __equal_3leg<__default_backend_tag, _ExecutionPolicy> {
323   template <class _Policy, class _ForwardIterator1, class _ForwardIterator2, class _Predicate>
324   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI optional<bool>
325   operator()(_Policy&& __policy,
326              _ForwardIterator1 __first1,
327              _ForwardIterator1 __last1,
328              _ForwardIterator2 __first2,
329              _Predicate&& __pred) const noexcept {
330     using _TransformReduce = __dispatch<__transform_reduce_binary, __current_configuration, _ExecutionPolicy>;
331     return _TransformReduce()(
332         __policy,
333         std::move(__first1),
334         std::move(__last1),
335         std::move(__first2),
336         true,
337         std::logical_and{},
338         std::forward<_Predicate>(__pred));
339   }
340 };
341 
342 template <class _ExecutionPolicy>
343 struct __equal<__default_backend_tag, _ExecutionPolicy> {
344   template <class _Policy, class _ForwardIterator1, class _ForwardIterator2, class _Predicate>
345   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI optional<bool>
346   operator()(_Policy&& __policy,
347              _ForwardIterator1 __first1,
348              _ForwardIterator1 __last1,
349              _ForwardIterator2 __first2,
350              _ForwardIterator2 __last2,
351              _Predicate&& __pred) const noexcept {
352     if constexpr (__has_random_access_iterator_category<_ForwardIterator1>::value &&
353                   __has_random_access_iterator_category<_ForwardIterator2>::value) {
354       if (__last1 - __first1 != __last2 - __first2)
355         return false;
356       // Fall back to the 3 legged algorithm
357       using _Equal3Leg = __dispatch<__equal_3leg, __current_configuration, _ExecutionPolicy>;
358       return _Equal3Leg()(
359           __policy, std::move(__first1), std::move(__last1), std::move(__first2), std::forward<_Predicate>(__pred));
360     } else {
361       // If we don't have random access, fall back to the serial algorithm cause we can't do much
362       return std::equal(
363           std::move(__first1),
364           std::move(__last1),
365           std::move(__first2),
366           std::move(__last2),
367           std::forward<_Predicate>(__pred));
368     }
369   }
370 };
371 
372 template <class _ExecutionPolicy>
373 struct __reduce<__default_backend_tag, _ExecutionPolicy> {
374   template <class _Policy, class _ForwardIterator, class _Tp, class _BinaryOperation>
375   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI optional<_Tp>
376   operator()(_Policy&& __policy, _ForwardIterator __first, _ForwardIterator __last, _Tp __init, _BinaryOperation&& __op)
377       const noexcept {
378     using _TransformReduce = __dispatch<__transform_reduce, __current_configuration, _ExecutionPolicy>;
379     return _TransformReduce()(
380         __policy,
381         std::move(__first),
382         std::move(__last),
383         std::move(__init),
384         std::forward<_BinaryOperation>(__op),
385         __identity{});
386   }
387 };
388 
389 //////////////////////////////////////////////////////////////
390 // transform family
391 //////////////////////////////////////////////////////////////
392 template <class _ExecutionPolicy>
393 struct __replace_copy_if<__default_backend_tag, _ExecutionPolicy> {
394   template <class _Policy, class _ForwardIterator, class _ForwardOutIterator, class _Pred, class _Tp>
395   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI optional<__empty>
396   operator()(_Policy&& __policy,
397              _ForwardIterator __first,
398              _ForwardIterator __last,
399              _ForwardOutIterator __out_it,
400              _Pred&& __pred,
401              _Tp const& __new_value) const noexcept {
402     using _Transform = __dispatch<__transform, __current_configuration, _ExecutionPolicy>;
403     using _Ref       = __iter_reference<_ForwardIterator>;
404     auto __res =
405         _Transform()(__policy, std::move(__first), std::move(__last), std::move(__out_it), [&](_Ref __element) {
406           return __pred(__element) ? __new_value : __element;
407         });
408     if (__res == nullopt)
409       return nullopt;
410     return __empty{};
411   }
412 };
413 
414 template <class _ExecutionPolicy>
415 struct __replace_copy<__default_backend_tag, _ExecutionPolicy> {
416   template <class _Policy, class _ForwardIterator, class _ForwardOutIterator, class _Tp>
417   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI optional<__empty>
418   operator()(_Policy&& __policy,
419              _ForwardIterator __first,
420              _ForwardIterator __last,
421              _ForwardOutIterator __out_it,
422              _Tp const& __old_value,
423              _Tp const& __new_value) const noexcept {
424     using _ReplaceCopyIf = __dispatch<__replace_copy_if, __current_configuration, _ExecutionPolicy>;
425     using _Ref           = __iter_reference<_ForwardIterator>;
426     return _ReplaceCopyIf()(
427         __policy,
428         std::move(__first),
429         std::move(__last),
430         std::move(__out_it),
431         [&](_Ref __element) { return __element == __old_value; },
432         __new_value);
433   }
434 };
435 
436 // TODO: Use the std::copy/move shenanigans to forward to std::memmove
437 //       Investigate whether we want to still forward to std::transform(policy)
438 //       in that case for the execution::par part, or whether we actually want
439 //       to run everything serially in that case.
440 template <class _ExecutionPolicy>
441 struct __move<__default_backend_tag, _ExecutionPolicy> {
442   template <class _Policy, class _ForwardIterator, class _ForwardOutIterator>
443   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI optional<_ForwardOutIterator>
444   operator()(_Policy&& __policy, _ForwardIterator __first, _ForwardIterator __last, _ForwardOutIterator __out_it)
445       const noexcept {
446     using _Transform = __dispatch<__transform, __current_configuration, _ExecutionPolicy>;
447     return _Transform()(__policy, std::move(__first), std::move(__last), std::move(__out_it), [&](auto&& __element) {
448       return std::move(__element);
449     });
450   }
451 };
452 
453 // TODO: Use the std::copy/move shenanigans to forward to std::memmove
454 template <class _ExecutionPolicy>
455 struct __copy<__default_backend_tag, _ExecutionPolicy> {
456   template <class _Policy, class _ForwardIterator, class _ForwardOutIterator>
457   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI optional<_ForwardOutIterator>
458   operator()(_Policy&& __policy, _ForwardIterator __first, _ForwardIterator __last, _ForwardOutIterator __out_it)
459       const noexcept {
460     using _Transform = __dispatch<__transform, __current_configuration, _ExecutionPolicy>;
461     return _Transform()(__policy, std::move(__first), std::move(__last), std::move(__out_it), __identity());
462   }
463 };
464 
465 template <class _ExecutionPolicy>
466 struct __copy_n<__default_backend_tag, _ExecutionPolicy> {
467   template <class _Policy, class _ForwardIterator, class _Size, class _ForwardOutIterator>
468   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI optional<_ForwardOutIterator>
469   operator()(_Policy&& __policy, _ForwardIterator __first, _Size __n, _ForwardOutIterator __out_it) const noexcept {
470     if constexpr (__has_random_access_iterator_category_or_concept<_ForwardIterator>::value) {
471       using _Copy             = __dispatch<__copy, __current_configuration, _ExecutionPolicy>;
472       _ForwardIterator __last = __first + __n;
473       return _Copy()(__policy, std::move(__first), std::move(__last), std::move(__out_it));
474     } else {
475       // Otherwise, use the serial algorithm to avoid doing two passes over the input
476       return std::copy_n(std::move(__first), __n, std::move(__out_it));
477     }
478   }
479 };
480 
481 template <class _ExecutionPolicy>
482 struct __rotate_copy<__default_backend_tag, _ExecutionPolicy> {
483   template <class _Policy, class _ForwardIterator, class _ForwardOutIterator>
484   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI optional<_ForwardOutIterator>
485   operator()(_Policy&& __policy,
486              _ForwardIterator __first,
487              _ForwardIterator __middle,
488              _ForwardIterator __last,
489              _ForwardOutIterator __out_it) const noexcept {
490     using _Copy       = __dispatch<__copy, __current_configuration, _ExecutionPolicy>;
491     auto __result_mid = _Copy()(__policy, __middle, std::move(__last), std::move(__out_it));
492     if (__result_mid == nullopt)
493       return nullopt;
494     return _Copy()(__policy, std::move(__first), std::move(__middle), *std::move(__result_mid));
495   }
496 };
497 
498 } // namespace __pstl
499 _LIBCPP_END_NAMESPACE_STD
500 
501 _LIBCPP_POP_MACROS
502 
503 #endif // _LIBCPP___PSTL_BACKENDS_DEFAULT_H
504