1 // Core algorithmic facilities -*- C++ -*-
3 // Copyright (C) 2020-2024 Free Software Foundation, Inc.
5 // This file is part of the GNU ISO C++ Library. This library is free
6 // software; you can redistribute it and/or modify it under the
7 // terms of the GNU General Public License as published by the
8 // Free Software Foundation; either version 3, or (at your option)
11 // This library is distributed in the hope that it will be useful,
12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 // GNU General Public License for more details.
16 // Under Section 7 of GPL version 3, you are granted additional
17 // permissions described in the GCC Runtime Library Exception, version
18 // 3.1, as published by the Free Software Foundation.
20 // You should have received a copy of the GNU General Public License and
21 // a copy of the GCC Runtime Library Exception along with this program;
22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23 // <http://www.gnu.org/licenses/>.
25 /** @file bits/ranges_algobase.h
26 * This is an internal header file, included by other library headers.
27 * Do not attempt to use it directly. @headername{algorithm}
30 #ifndef _RANGES_ALGOBASE_H
31 #define _RANGES_ALGOBASE_H 1
33 #if __cplusplus > 201703L
36 #include <bits/stl_iterator_base_funcs.h>
37 #include <bits/stl_iterator.h>
38 #include <bits/ranges_base.h> // ranges::begin, ranges::range etc.
39 #include <bits/invoke.h> // __invoke
40 #include <bits/cpp_type_traits.h> // __is_byte
42 #if __cpp_lib_concepts
43 namespace std
_GLIBCXX_VISIBILITY(default)
45 _GLIBCXX_BEGIN_NAMESPACE_VERSION
50 template<typename _Tp
>
51 constexpr inline bool __is_normal_iterator
= false;
53 template<typename _Iterator
, typename _Container
>
55 __is_normal_iterator
<__gnu_cxx::__normal_iterator
<_Iterator
,
58 template<typename _Tp
>
59 constexpr inline bool __is_reverse_iterator
= false;
61 template<typename _Iterator
>
63 __is_reverse_iterator
<reverse_iterator
<_Iterator
>> = true;
65 template<typename _Tp
>
66 constexpr inline bool __is_move_iterator
= false;
68 template<typename _Iterator
>
70 __is_move_iterator
<move_iterator
<_Iterator
>> = true;
71 } // namespace __detail
75 template<input_iterator _Iter1
, sentinel_for
<_Iter1
> _Sent1
,
76 input_iterator _Iter2
, sentinel_for
<_Iter2
> _Sent2
,
77 typename _Pred
= ranges::equal_to
,
78 typename _Proj1
= identity
, typename _Proj2
= identity
>
79 requires indirectly_comparable
<_Iter1
, _Iter2
, _Pred
, _Proj1
, _Proj2
>
81 operator()(_Iter1 __first1
, _Sent1 __last1
,
82 _Iter2 __first2
, _Sent2 __last2
, _Pred __pred
= {},
83 _Proj1 __proj1
= {}, _Proj2 __proj2
= {}) const
85 // TODO: implement more specializations to at least have parity with
87 if constexpr (__detail::__is_normal_iterator
<_Iter1
>
88 && same_as
<_Iter1
, _Sent1
>)
89 return (*this)(__first1
.base(), __last1
.base(),
90 std::move(__first2
), std::move(__last2
),
92 std::move(__proj1
), std::move(__proj2
));
93 else if constexpr (__detail::__is_normal_iterator
<_Iter2
>
94 && same_as
<_Iter2
, _Sent2
>)
95 return (*this)(std::move(__first1
), std::move(__last1
),
96 __first2
.base(), __last2
.base(),
98 std::move(__proj1
), std::move(__proj2
));
99 else if constexpr (sized_sentinel_for
<_Sent1
, _Iter1
>
100 && sized_sentinel_for
<_Sent2
, _Iter2
>)
102 auto __d1
= ranges::distance(__first1
, __last1
);
103 auto __d2
= ranges::distance(__first2
, __last2
);
107 using _ValueType1
= iter_value_t
<_Iter1
>;
108 constexpr bool __use_memcmp
109 = ((is_integral_v
<_ValueType1
> || is_pointer_v
<_ValueType1
>)
110 && __memcmpable
<_Iter1
, _Iter2
>::__value
111 && is_same_v
<_Pred
, ranges::equal_to
>
112 && is_same_v
<_Proj1
, identity
>
113 && is_same_v
<_Proj2
, identity
>);
114 if constexpr (__use_memcmp
)
116 if (const size_t __len
= (__last1
- __first1
))
117 return !std::__memcmp(__first1
, __first2
, __len
);
122 for (; __first1
!= __last1
; ++__first1
, (void)++__first2
)
123 if (!(bool)std::__invoke(__pred
,
124 std::__invoke(__proj1
, *__first1
),
125 std::__invoke(__proj2
, *__first2
)))
132 for (; __first1
!= __last1
&& __first2
!= __last2
;
133 ++__first1
, (void)++__first2
)
134 if (!(bool)std::__invoke(__pred
,
135 std::__invoke(__proj1
, *__first1
),
136 std::__invoke(__proj2
, *__first2
)))
138 return __first1
== __last1
&& __first2
== __last2
;
142 template<input_range _Range1
, input_range _Range2
,
143 typename _Pred
= ranges::equal_to
,
144 typename _Proj1
= identity
, typename _Proj2
= identity
>
145 requires indirectly_comparable
<iterator_t
<_Range1
>, iterator_t
<_Range2
>,
146 _Pred
, _Proj1
, _Proj2
>
148 operator()(_Range1
&& __r1
, _Range2
&& __r2
, _Pred __pred
= {},
149 _Proj1 __proj1
= {}, _Proj2 __proj2
= {}) const
151 return (*this)(ranges::begin(__r1
), ranges::end(__r1
),
152 ranges::begin(__r2
), ranges::end(__r2
),
154 std::move(__proj1
), std::move(__proj2
));
158 inline constexpr __equal_fn equal
{};
160 template<typename _Iter
, typename _Out
>
163 [[no_unique_address
]] _Iter in
;
164 [[no_unique_address
]] _Out out
;
166 template<typename _Iter2
, typename _Out2
>
167 requires convertible_to
<const _Iter
&, _Iter2
>
168 && convertible_to
<const _Out
&, _Out2
>
170 operator in_out_result
<_Iter2
, _Out2
>() const &
171 { return {in
, out
}; }
173 template<typename _Iter2
, typename _Out2
>
174 requires convertible_to
<_Iter
, _Iter2
>
175 && convertible_to
<_Out
, _Out2
>
177 operator in_out_result
<_Iter2
, _Out2
>() &&
178 { return {std::move(in
), std::move(out
)}; }
181 template<typename _Iter
, typename _Out
>
182 using copy_result
= in_out_result
<_Iter
, _Out
>;
184 template<typename _Iter
, typename _Out
>
185 using move_result
= in_out_result
<_Iter
, _Out
>;
187 template<typename _Iter1
, typename _Iter2
>
188 using move_backward_result
= in_out_result
<_Iter1
, _Iter2
>;
190 template<typename _Iter1
, typename _Iter2
>
191 using copy_backward_result
= in_out_result
<_Iter1
, _Iter2
>;
193 template<bool _IsMove
,
194 bidirectional_iterator _Iter
, sentinel_for
<_Iter
> _Sent
,
195 bidirectional_iterator _Out
>
197 ? indirectly_movable
<_Iter
, _Out
>
198 : indirectly_copyable
<_Iter
, _Out
>)
199 constexpr __conditional_t
<_IsMove
,
200 move_backward_result
<_Iter
, _Out
>,
201 copy_backward_result
<_Iter
, _Out
>>
202 __copy_or_move_backward(_Iter __first
, _Sent __last
, _Out __result
);
204 template<bool _IsMove
,
205 input_iterator _Iter
, sentinel_for
<_Iter
> _Sent
,
206 weakly_incrementable _Out
>
208 ? indirectly_movable
<_Iter
, _Out
>
209 : indirectly_copyable
<_Iter
, _Out
>)
210 constexpr __conditional_t
<_IsMove
,
211 move_result
<_Iter
, _Out
>,
212 copy_result
<_Iter
, _Out
>>
213 __copy_or_move(_Iter __first
, _Sent __last
, _Out __result
)
215 // TODO: implement more specializations to be at least on par with
216 // std::copy/std::move.
217 using __detail::__is_move_iterator
;
218 using __detail::__is_reverse_iterator
;
219 using __detail::__is_normal_iterator
;
220 if constexpr (__is_move_iterator
<_Iter
> && same_as
<_Iter
, _Sent
>)
223 = ranges::__copy_or_move
<true>(std::move(__first
).base(),
224 std::move(__last
).base(),
225 std::move(__result
));
226 return {move_iterator
{std::move(__in
)}, std::move(__out
)};
228 else if constexpr (__is_reverse_iterator
<_Iter
> && same_as
<_Iter
, _Sent
>
229 && __is_reverse_iterator
<_Out
>)
232 = ranges::__copy_or_move_backward
<_IsMove
>(std::move(__last
).base(),
233 std::move(__first
).base(),
234 std::move(__result
).base());
235 return {reverse_iterator
{std::move(__in
)},
236 reverse_iterator
{std::move(__out
)}};
238 else if constexpr (__is_normal_iterator
<_Iter
> && same_as
<_Iter
, _Sent
>)
241 = ranges::__copy_or_move
<_IsMove
>(__first
.base(), __last
.base(),
242 std::move(__result
));
243 return {decltype(__first
){__in
}, std::move(__out
)};
245 else if constexpr (__is_normal_iterator
<_Out
>)
248 = ranges::__copy_or_move
<_IsMove
>(std::move(__first
), __last
, __result
.base());
249 return {std::move(__in
), decltype(__result
){__out
}};
251 else if constexpr (sized_sentinel_for
<_Sent
, _Iter
>)
253 if (!std::__is_constant_evaluated())
255 if constexpr (__memcpyable
<_Iter
, _Out
>::__value
)
257 using _ValueTypeI
= iter_value_t
<_Iter
>;
258 static_assert(_IsMove
259 ? is_move_assignable_v
<_ValueTypeI
>
260 : is_copy_assignable_v
<_ValueTypeI
>);
261 auto __num
= __last
- __first
;
263 __builtin_memmove(__result
, __first
,
264 sizeof(_ValueTypeI
) * __num
);
265 return {__first
+ __num
, __result
+ __num
};
269 for (auto __n
= __last
- __first
; __n
> 0; --__n
)
271 if constexpr (_IsMove
)
272 *__result
= std::move(*__first
);
274 *__result
= *__first
;
278 return {std::move(__first
), std::move(__result
)};
282 while (__first
!= __last
)
284 if constexpr (_IsMove
)
285 *__result
= std::move(*__first
);
287 *__result
= *__first
;
291 return {std::move(__first
), std::move(__result
)};
297 template<input_iterator _Iter
, sentinel_for
<_Iter
> _Sent
,
298 weakly_incrementable _Out
>
299 requires indirectly_copyable
<_Iter
, _Out
>
300 constexpr copy_result
<_Iter
, _Out
>
301 operator()(_Iter __first
, _Sent __last
, _Out __result
) const
303 return ranges::__copy_or_move
<false>(std::move(__first
),
305 std::move(__result
));
308 template<input_range _Range
, weakly_incrementable _Out
>
309 requires indirectly_copyable
<iterator_t
<_Range
>, _Out
>
310 constexpr copy_result
<borrowed_iterator_t
<_Range
>, _Out
>
311 operator()(_Range
&& __r
, _Out __result
) const
313 return (*this)(ranges::begin(__r
), ranges::end(__r
),
314 std::move(__result
));
318 inline constexpr __copy_fn copy
{};
322 template<input_iterator _Iter
, sentinel_for
<_Iter
> _Sent
,
323 weakly_incrementable _Out
>
324 requires indirectly_movable
<_Iter
, _Out
>
325 constexpr move_result
<_Iter
, _Out
>
326 operator()(_Iter __first
, _Sent __last
, _Out __result
) const
328 return ranges::__copy_or_move
<true>(std::move(__first
),
330 std::move(__result
));
333 template<input_range _Range
, weakly_incrementable _Out
>
334 requires indirectly_movable
<iterator_t
<_Range
>, _Out
>
335 constexpr move_result
<borrowed_iterator_t
<_Range
>, _Out
>
336 operator()(_Range
&& __r
, _Out __result
) const
338 return (*this)(ranges::begin(__r
), ranges::end(__r
),
339 std::move(__result
));
343 inline constexpr __move_fn move
{};
345 template<bool _IsMove
,
346 bidirectional_iterator _Iter
, sentinel_for
<_Iter
> _Sent
,
347 bidirectional_iterator _Out
>
349 ? indirectly_movable
<_Iter
, _Out
>
350 : indirectly_copyable
<_Iter
, _Out
>)
351 constexpr __conditional_t
<_IsMove
,
352 move_backward_result
<_Iter
, _Out
>,
353 copy_backward_result
<_Iter
, _Out
>>
354 __copy_or_move_backward(_Iter __first
, _Sent __last
, _Out __result
)
356 // TODO: implement more specializations to be at least on par with
357 // std::copy_backward/std::move_backward.
358 using __detail::__is_reverse_iterator
;
359 using __detail::__is_normal_iterator
;
360 if constexpr (__is_reverse_iterator
<_Iter
> && same_as
<_Iter
, _Sent
>
361 && __is_reverse_iterator
<_Out
>)
364 = ranges::__copy_or_move
<_IsMove
>(std::move(__last
).base(),
365 std::move(__first
).base(),
366 std::move(__result
).base());
367 return {reverse_iterator
{std::move(__in
)},
368 reverse_iterator
{std::move(__out
)}};
370 else if constexpr (__is_normal_iterator
<_Iter
> && same_as
<_Iter
, _Sent
>)
373 = ranges::__copy_or_move_backward
<_IsMove
>(__first
.base(),
375 std::move(__result
));
376 return {decltype(__first
){__in
}, std::move(__out
)};
378 else if constexpr (__is_normal_iterator
<_Out
>)
381 = ranges::__copy_or_move_backward
<_IsMove
>(std::move(__first
),
384 return {std::move(__in
), decltype(__result
){__out
}};
386 else if constexpr (sized_sentinel_for
<_Sent
, _Iter
>)
388 if (!std::__is_constant_evaluated())
390 if constexpr (__memcpyable
<_Out
, _Iter
>::__value
)
392 using _ValueTypeI
= iter_value_t
<_Iter
>;
393 static_assert(_IsMove
394 ? is_move_assignable_v
<_ValueTypeI
>
395 : is_copy_assignable_v
<_ValueTypeI
>);
396 auto __num
= __last
- __first
;
398 __builtin_memmove(__result
- __num
, __first
,
399 sizeof(_ValueTypeI
) * __num
);
400 return {__first
+ __num
, __result
- __num
};
404 auto __lasti
= ranges::next(__first
, __last
);
405 auto __tail
= __lasti
;
407 for (auto __n
= __last
- __first
; __n
> 0; --__n
)
411 if constexpr (_IsMove
)
412 *__result
= std::move(*__tail
);
416 return {std::move(__lasti
), std::move(__result
)};
420 auto __lasti
= ranges::next(__first
, __last
);
421 auto __tail
= __lasti
;
423 while (__first
!= __tail
)
427 if constexpr (_IsMove
)
428 *__result
= std::move(*__tail
);
432 return {std::move(__lasti
), std::move(__result
)};
436 struct __copy_backward_fn
438 template<bidirectional_iterator _Iter1
, sentinel_for
<_Iter1
> _Sent1
,
439 bidirectional_iterator _Iter2
>
440 requires indirectly_copyable
<_Iter1
, _Iter2
>
441 constexpr copy_backward_result
<_Iter1
, _Iter2
>
442 operator()(_Iter1 __first
, _Sent1 __last
, _Iter2 __result
) const
444 return ranges::__copy_or_move_backward
<false>(std::move(__first
),
446 std::move(__result
));
449 template<bidirectional_range _Range
, bidirectional_iterator _Iter
>
450 requires indirectly_copyable
<iterator_t
<_Range
>, _Iter
>
451 constexpr copy_backward_result
<borrowed_iterator_t
<_Range
>, _Iter
>
452 operator()(_Range
&& __r
, _Iter __result
) const
454 return (*this)(ranges::begin(__r
), ranges::end(__r
),
455 std::move(__result
));
459 inline constexpr __copy_backward_fn copy_backward
{};
461 struct __move_backward_fn
463 template<bidirectional_iterator _Iter1
, sentinel_for
<_Iter1
> _Sent1
,
464 bidirectional_iterator _Iter2
>
465 requires indirectly_movable
<_Iter1
, _Iter2
>
466 constexpr move_backward_result
<_Iter1
, _Iter2
>
467 operator()(_Iter1 __first
, _Sent1 __last
, _Iter2 __result
) const
469 return ranges::__copy_or_move_backward
<true>(std::move(__first
),
471 std::move(__result
));
474 template<bidirectional_range _Range
, bidirectional_iterator _Iter
>
475 requires indirectly_movable
<iterator_t
<_Range
>, _Iter
>
476 constexpr move_backward_result
<borrowed_iterator_t
<_Range
>, _Iter
>
477 operator()(_Range
&& __r
, _Iter __result
) const
479 return (*this)(ranges::begin(__r
), ranges::end(__r
),
480 std::move(__result
));
484 inline constexpr __move_backward_fn move_backward
{};
486 template<typename _Iter
, typename _Out
>
487 using copy_n_result
= in_out_result
<_Iter
, _Out
>;
491 template<input_iterator _Iter
, weakly_incrementable _Out
>
492 requires indirectly_copyable
<_Iter
, _Out
>
493 constexpr copy_n_result
<_Iter
, _Out
>
494 operator()(_Iter __first
, iter_difference_t
<_Iter
> __n
,
497 if constexpr (random_access_iterator
<_Iter
>)
500 return ranges::copy(__first
, __first
+ __n
, std::move(__result
));
504 for (; __n
> 0; --__n
, (void)++__result
, (void)++__first
)
505 *__result
= *__first
;
507 return {std::move(__first
), std::move(__result
)};
511 inline constexpr __copy_n_fn copy_n
{};
515 template<typename _Tp
, output_iterator
<const _Tp
&> _Out
>
517 operator()(_Out __first
, iter_difference_t
<_Out
> __n
,
518 const _Tp
& __value
) const
520 // TODO: implement more specializations to be at least on par with
525 if constexpr (is_scalar_v
<_Tp
>)
527 // TODO: Generalize this optimization to contiguous iterators.
528 if constexpr (is_pointer_v
<_Out
>
529 // Note that __is_byte already implies !is_volatile.
530 && __is_byte
<remove_pointer_t
<_Out
>>::__value
533 if (!std::__is_constant_evaluated())
535 __builtin_memset(__first
,
536 static_cast<unsigned char>(__value
),
538 return __first
+ __n
;
542 const auto __tmp
= __value
;
543 for (; __n
> 0; --__n
, (void)++__first
)
549 for (; __n
> 0; --__n
, (void)++__first
)
556 inline constexpr __fill_n_fn fill_n
{};
560 template<typename _Tp
,
561 output_iterator
<const _Tp
&> _Out
, sentinel_for
<_Out
> _Sent
>
563 operator()(_Out __first
, _Sent __last
, const _Tp
& __value
) const
565 // TODO: implement more specializations to be at least on par with
567 if constexpr (sized_sentinel_for
<_Sent
, _Out
>)
569 const auto __len
= __last
- __first
;
570 return ranges::fill_n(__first
, __len
, __value
);
572 else if constexpr (is_scalar_v
<_Tp
>)
574 const auto __tmp
= __value
;
575 for (; __first
!= __last
; ++__first
)
581 for (; __first
!= __last
; ++__first
)
587 template<typename _Tp
, output_range
<const _Tp
&> _Range
>
588 constexpr borrowed_iterator_t
<_Range
>
589 operator()(_Range
&& __r
, const _Tp
& __value
) const
591 return (*this)(ranges::begin(__r
), ranges::end(__r
), __value
);
595 inline constexpr __fill_fn fill
{};
597 _GLIBCXX_END_NAMESPACE_VERSION
601 #endif // _RANGES_ALGOBASE_H