1 // Core algorithmic facilities -*- C++ -*-
3 // Copyright (C) 2020-2021 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
37 #include <bits/ranges_base.h> // ranges::begin, ranges::range etc.
38 #include <bits/invoke.h> // __invoke
39 #include <bits/cpp_type_traits.h> // __is_byte
41 #if __cpp_lib_concepts
42 namespace std
_GLIBCXX_VISIBILITY(default)
44 _GLIBCXX_BEGIN_NAMESPACE_VERSION
49 template<typename _Tp
>
50 constexpr inline bool __is_normal_iterator
= false;
52 template<typename _Iterator
, typename _Container
>
54 __is_normal_iterator
<__gnu_cxx::__normal_iterator
<_Iterator
,
57 template<typename _Tp
>
58 constexpr inline bool __is_reverse_iterator
= false;
60 template<typename _Iterator
>
62 __is_reverse_iterator
<reverse_iterator
<_Iterator
>> = true;
64 template<typename _Tp
>
65 constexpr inline bool __is_move_iterator
= false;
67 template<typename _Iterator
>
69 __is_move_iterator
<move_iterator
<_Iterator
>> = true;
70 } // namespace __detail
74 template<input_iterator _Iter1
, sentinel_for
<_Iter1
> _Sent1
,
75 input_iterator _Iter2
, sentinel_for
<_Iter2
> _Sent2
,
76 typename _Pred
= ranges::equal_to
,
77 typename _Proj1
= identity
, typename _Proj2
= identity
>
78 requires indirectly_comparable
<_Iter1
, _Iter2
, _Pred
, _Proj1
, _Proj2
>
80 operator()(_Iter1 __first1
, _Sent1 __last1
,
81 _Iter2 __first2
, _Sent2 __last2
, _Pred __pred
= {},
82 _Proj1 __proj1
= {}, _Proj2 __proj2
= {}) const
84 // TODO: implement more specializations to at least have parity with
86 if constexpr (__detail::__is_normal_iterator
<_Iter1
>
87 && same_as
<_Iter1
, _Sent1
>)
88 return (*this)(__first1
.base(), __last1
.base(),
89 std::move(__first2
), std::move(__last2
),
91 std::move(__proj1
), std::move(__proj2
));
92 else if constexpr (__detail::__is_normal_iterator
<_Iter2
>
93 && same_as
<_Iter2
, _Sent2
>)
94 return (*this)(std::move(__first1
), std::move(__last1
),
95 __first2
.base(), __last2
.base(),
97 std::move(__proj1
), std::move(__proj2
));
98 else if constexpr (sized_sentinel_for
<_Sent1
, _Iter1
>
99 && sized_sentinel_for
<_Sent2
, _Iter2
>)
101 auto __d1
= ranges::distance(__first1
, __last1
);
102 auto __d2
= ranges::distance(__first2
, __last2
);
106 using _ValueType1
= iter_value_t
<_Iter1
>;
107 constexpr bool __use_memcmp
108 = ((is_integral_v
<_ValueType1
> || is_pointer_v
<_ValueType1
>)
109 && __memcmpable
<_Iter1
, _Iter2
>::__value
110 && is_same_v
<_Pred
, ranges::equal_to
>
111 && is_same_v
<_Proj1
, identity
>
112 && is_same_v
<_Proj2
, identity
>);
113 if constexpr (__use_memcmp
)
115 if (const size_t __len
= (__last1
- __first1
))
116 return !std::__memcmp(__first1
, __first2
, __len
);
121 for (; __first1
!= __last1
; ++__first1
, (void)++__first2
)
122 if (!(bool)std::__invoke(__pred
,
123 std::__invoke(__proj1
, *__first1
),
124 std::__invoke(__proj2
, *__first2
)))
131 for (; __first1
!= __last1
&& __first2
!= __last2
;
132 ++__first1
, (void)++__first2
)
133 if (!(bool)std::__invoke(__pred
,
134 std::__invoke(__proj1
, *__first1
),
135 std::__invoke(__proj2
, *__first2
)))
137 return __first1
== __last1
&& __first2
== __last2
;
141 template<input_range _Range1
, input_range _Range2
,
142 typename _Pred
= ranges::equal_to
,
143 typename _Proj1
= identity
, typename _Proj2
= identity
>
144 requires indirectly_comparable
<iterator_t
<_Range1
>, iterator_t
<_Range2
>,
145 _Pred
, _Proj1
, _Proj2
>
147 operator()(_Range1
&& __r1
, _Range2
&& __r2
, _Pred __pred
= {},
148 _Proj1 __proj1
= {}, _Proj2 __proj2
= {}) const
150 return (*this)(ranges::begin(__r1
), ranges::end(__r1
),
151 ranges::begin(__r2
), ranges::end(__r2
),
153 std::move(__proj1
), std::move(__proj2
));
157 inline constexpr __equal_fn equal
{};
159 template<typename _Iter
, typename _Out
>
162 [[no_unique_address
]] _Iter in
;
163 [[no_unique_address
]] _Out out
;
165 template<typename _Iter2
, typename _Out2
>
166 requires convertible_to
<const _Iter
&, _Iter2
>
167 && convertible_to
<const _Out
&, _Out2
>
169 operator in_out_result
<_Iter2
, _Out2
>() const &
170 { return {in
, out
}; }
172 template<typename _Iter2
, typename _Out2
>
173 requires convertible_to
<_Iter
, _Iter2
>
174 && convertible_to
<_Out
, _Out2
>
176 operator in_out_result
<_Iter2
, _Out2
>() &&
177 { return {std::move(in
), std::move(out
)}; }
180 template<typename _Iter
, typename _Out
>
181 using copy_result
= in_out_result
<_Iter
, _Out
>;
183 template<typename _Iter
, typename _Out
>
184 using move_result
= in_out_result
<_Iter
, _Out
>;
186 template<typename _Iter1
, typename _Iter2
>
187 using move_backward_result
= in_out_result
<_Iter1
, _Iter2
>;
189 template<typename _Iter1
, typename _Iter2
>
190 using copy_backward_result
= in_out_result
<_Iter1
, _Iter2
>;
192 template<bool _IsMove
,
193 bidirectional_iterator _Iter
, sentinel_for
<_Iter
> _Sent
,
194 bidirectional_iterator _Out
>
196 ? indirectly_movable
<_Iter
, _Out
>
197 : indirectly_copyable
<_Iter
, _Out
>)
198 constexpr conditional_t
<_IsMove
,
199 move_backward_result
<_Iter
, _Out
>,
200 copy_backward_result
<_Iter
, _Out
>>
201 __copy_or_move_backward(_Iter __first
, _Sent __last
, _Out __result
);
203 template<bool _IsMove
,
204 input_iterator _Iter
, sentinel_for
<_Iter
> _Sent
,
205 weakly_incrementable _Out
>
207 ? indirectly_movable
<_Iter
, _Out
>
208 : indirectly_copyable
<_Iter
, _Out
>)
209 constexpr conditional_t
<_IsMove
,
210 move_result
<_Iter
, _Out
>,
211 copy_result
<_Iter
, _Out
>>
212 __copy_or_move(_Iter __first
, _Sent __last
, _Out __result
)
214 // TODO: implement more specializations to be at least on par with
215 // std::copy/std::move.
216 using __detail::__is_move_iterator
;
217 using __detail::__is_reverse_iterator
;
218 using __detail::__is_normal_iterator
;
219 if constexpr (__is_move_iterator
<_Iter
> && same_as
<_Iter
, _Sent
>)
222 = ranges::__copy_or_move
<true>(std::move(__first
).base(),
223 std::move(__last
).base(),
224 std::move(__result
));
225 return {move_iterator
{std::move(__in
)}, std::move(__out
)};
227 else if constexpr (__is_reverse_iterator
<_Iter
> && same_as
<_Iter
, _Sent
>
228 && __is_reverse_iterator
<_Out
>)
231 = ranges::__copy_or_move_backward
<_IsMove
>(std::move(__last
).base(),
232 std::move(__first
).base(),
233 std::move(__result
).base());
234 return {reverse_iterator
{std::move(__in
)},
235 reverse_iterator
{std::move(__out
)}};
237 else if constexpr (__is_normal_iterator
<_Iter
> && same_as
<_Iter
, _Sent
>)
240 = ranges::__copy_or_move
<_IsMove
>(__first
.base(), __last
.base(),
242 return {decltype(__first
){__in
}, std::move(__out
)};
244 else if constexpr (__is_normal_iterator
<_Out
>)
247 = ranges::__copy_or_move
<_IsMove
>(__first
, __last
, __result
.base());
248 return {std::move(__in
), decltype(__result
){__out
}};
250 else if constexpr (sized_sentinel_for
<_Sent
, _Iter
>)
252 #ifdef __cpp_lib_is_constant_evaluated
253 if (!std::is_constant_evaluated())
256 if constexpr (__memcpyable
<_Iter
, _Out
>::__value
)
258 using _ValueTypeI
= iter_value_t
<_Iter
>;
259 static_assert(_IsMove
260 ? is_move_assignable_v
<_ValueTypeI
>
261 : is_copy_assignable_v
<_ValueTypeI
>);
262 auto __num
= __last
- __first
;
264 __builtin_memmove(__result
, __first
,
265 sizeof(_ValueTypeI
) * __num
);
266 return {__first
+ __num
, __result
+ __num
};
270 for (auto __n
= __last
- __first
; __n
> 0; --__n
)
272 if constexpr (_IsMove
)
273 *__result
= std::move(*__first
);
275 *__result
= *__first
;
279 return {std::move(__first
), std::move(__result
)};
283 while (__first
!= __last
)
285 if constexpr (_IsMove
)
286 *__result
= std::move(*__first
);
288 *__result
= *__first
;
292 return {std::move(__first
), std::move(__result
)};
298 template<input_iterator _Iter
, sentinel_for
<_Iter
> _Sent
,
299 weakly_incrementable _Out
>
300 requires indirectly_copyable
<_Iter
, _Out
>
301 constexpr copy_result
<_Iter
, _Out
>
302 operator()(_Iter __first
, _Sent __last
, _Out __result
) const
304 return ranges::__copy_or_move
<false>(std::move(__first
),
306 std::move(__result
));
309 template<input_range _Range
, weakly_incrementable _Out
>
310 requires indirectly_copyable
<iterator_t
<_Range
>, _Out
>
311 constexpr copy_result
<borrowed_iterator_t
<_Range
>, _Out
>
312 operator()(_Range
&& __r
, _Out __result
) const
314 return (*this)(ranges::begin(__r
), ranges::end(__r
),
315 std::move(__result
));
319 inline constexpr __copy_fn copy
{};
323 template<input_iterator _Iter
, sentinel_for
<_Iter
> _Sent
,
324 weakly_incrementable _Out
>
325 requires indirectly_movable
<_Iter
, _Out
>
326 constexpr move_result
<_Iter
, _Out
>
327 operator()(_Iter __first
, _Sent __last
, _Out __result
) const
329 return ranges::__copy_or_move
<true>(std::move(__first
),
331 std::move(__result
));
334 template<input_range _Range
, weakly_incrementable _Out
>
335 requires indirectly_movable
<iterator_t
<_Range
>, _Out
>
336 constexpr move_result
<borrowed_iterator_t
<_Range
>, _Out
>
337 operator()(_Range
&& __r
, _Out __result
) const
339 return (*this)(ranges::begin(__r
), ranges::end(__r
),
340 std::move(__result
));
344 inline constexpr __move_fn move
{};
346 template<bool _IsMove
,
347 bidirectional_iterator _Iter
, sentinel_for
<_Iter
> _Sent
,
348 bidirectional_iterator _Out
>
350 ? indirectly_movable
<_Iter
, _Out
>
351 : indirectly_copyable
<_Iter
, _Out
>)
352 constexpr conditional_t
<_IsMove
,
353 move_backward_result
<_Iter
, _Out
>,
354 copy_backward_result
<_Iter
, _Out
>>
355 __copy_or_move_backward(_Iter __first
, _Sent __last
, _Out __result
)
357 // TODO: implement more specializations to be at least on par with
358 // std::copy_backward/std::move_backward.
359 using __detail::__is_reverse_iterator
;
360 using __detail::__is_normal_iterator
;
361 if constexpr (__is_reverse_iterator
<_Iter
> && same_as
<_Iter
, _Sent
>
362 && __is_reverse_iterator
<_Out
>)
365 = ranges::__copy_or_move
<_IsMove
>(std::move(__last
).base(),
366 std::move(__first
).base(),
367 std::move(__result
).base());
368 return {reverse_iterator
{std::move(__in
)},
369 reverse_iterator
{std::move(__out
)}};
371 else if constexpr (__is_normal_iterator
<_Iter
> && same_as
<_Iter
, _Sent
>)
374 = ranges::__copy_or_move_backward
<_IsMove
>(__first
.base(),
376 std::move(__result
));
377 return {decltype(__first
){__in
}, std::move(__out
)};
379 else if constexpr (__is_normal_iterator
<_Out
>)
382 = ranges::__copy_or_move_backward
<_IsMove
>(std::move(__first
),
385 return {std::move(__in
), decltype(__result
){__out
}};
387 else if constexpr (sized_sentinel_for
<_Sent
, _Iter
>)
389 #ifdef __cpp_lib_is_constant_evaluated
390 if (!std::is_constant_evaluated())
393 if constexpr (__memcpyable
<_Out
, _Iter
>::__value
)
395 using _ValueTypeI
= iter_value_t
<_Iter
>;
396 static_assert(_IsMove
397 ? is_move_assignable_v
<_ValueTypeI
>
398 : is_copy_assignable_v
<_ValueTypeI
>);
399 auto __num
= __last
- __first
;
401 __builtin_memmove(__result
- __num
, __first
,
402 sizeof(_ValueTypeI
) * __num
);
403 return {__first
+ __num
, __result
- __num
};
407 auto __lasti
= ranges::next(__first
, __last
);
408 auto __tail
= __lasti
;
410 for (auto __n
= __last
- __first
; __n
> 0; --__n
)
414 if constexpr (_IsMove
)
415 *__result
= std::move(*__tail
);
419 return {std::move(__lasti
), std::move(__result
)};
423 auto __lasti
= ranges::next(__first
, __last
);
424 auto __tail
= __lasti
;
426 while (__first
!= __tail
)
430 if constexpr (_IsMove
)
431 *__result
= std::move(*__tail
);
435 return {std::move(__lasti
), std::move(__result
)};
439 struct __copy_backward_fn
441 template<bidirectional_iterator _Iter1
, sentinel_for
<_Iter1
> _Sent1
,
442 bidirectional_iterator _Iter2
>
443 requires indirectly_copyable
<_Iter1
, _Iter2
>
444 constexpr copy_backward_result
<_Iter1
, _Iter2
>
445 operator()(_Iter1 __first
, _Sent1 __last
, _Iter2 __result
) const
447 return ranges::__copy_or_move_backward
<false>(std::move(__first
),
449 std::move(__result
));
452 template<bidirectional_range _Range
, bidirectional_iterator _Iter
>
453 requires indirectly_copyable
<iterator_t
<_Range
>, _Iter
>
454 constexpr copy_backward_result
<borrowed_iterator_t
<_Range
>, _Iter
>
455 operator()(_Range
&& __r
, _Iter __result
) const
457 return (*this)(ranges::begin(__r
), ranges::end(__r
),
458 std::move(__result
));
462 inline constexpr __copy_backward_fn copy_backward
{};
464 struct __move_backward_fn
466 template<bidirectional_iterator _Iter1
, sentinel_for
<_Iter1
> _Sent1
,
467 bidirectional_iterator _Iter2
>
468 requires indirectly_movable
<_Iter1
, _Iter2
>
469 constexpr move_backward_result
<_Iter1
, _Iter2
>
470 operator()(_Iter1 __first
, _Sent1 __last
, _Iter2 __result
) const
472 return ranges::__copy_or_move_backward
<true>(std::move(__first
),
474 std::move(__result
));
477 template<bidirectional_range _Range
, bidirectional_iterator _Iter
>
478 requires indirectly_movable
<iterator_t
<_Range
>, _Iter
>
479 constexpr move_backward_result
<borrowed_iterator_t
<_Range
>, _Iter
>
480 operator()(_Range
&& __r
, _Iter __result
) const
482 return (*this)(ranges::begin(__r
), ranges::end(__r
),
483 std::move(__result
));
487 inline constexpr __move_backward_fn move_backward
{};
489 template<typename _Iter
, typename _Out
>
490 using copy_n_result
= in_out_result
<_Iter
, _Out
>;
494 template<input_iterator _Iter
, weakly_incrementable _Out
>
495 requires indirectly_copyable
<_Iter
, _Out
>
496 constexpr copy_n_result
<_Iter
, _Out
>
497 operator()(_Iter __first
, iter_difference_t
<_Iter
> __n
,
500 if constexpr (random_access_iterator
<_Iter
>)
503 return ranges::copy(__first
, __first
+ __n
, std::move(__result
));
507 for (; __n
> 0; --__n
, (void)++__result
, (void)++__first
)
508 *__result
= *__first
;
510 return {std::move(__first
), std::move(__result
)};
514 inline constexpr __copy_n_fn copy_n
{};
518 template<typename _Tp
, output_iterator
<const _Tp
&> _Out
>
520 operator()(_Out __first
, iter_difference_t
<_Out
> __n
,
521 const _Tp
& __value
) const
523 // TODO: implement more specializations to be at least on par with
528 // TODO: Generalize this optimization to contiguous iterators.
529 if constexpr (is_pointer_v
<_Out
>
530 // Note that __is_byte already implies !is_volatile.
531 && __is_byte
<remove_pointer_t
<_Out
>>::__value
534 __builtin_memset(__first
, static_cast<unsigned char>(__value
), __n
);
535 return __first
+ __n
;
537 else if constexpr (is_scalar_v
<_Tp
>)
539 const auto __tmp
= __value
;
540 for (; __n
> 0; --__n
, (void)++__first
)
546 for (; __n
> 0; --__n
, (void)++__first
)
553 inline constexpr __fill_n_fn fill_n
{};
557 template<typename _Tp
,
558 output_iterator
<const _Tp
&> _Out
, sentinel_for
<_Out
> _Sent
>
560 operator()(_Out __first
, _Sent __last
, const _Tp
& __value
) const
562 // TODO: implement more specializations to be at least on par with
564 if constexpr (sized_sentinel_for
<_Sent
, _Out
>)
566 const auto __len
= __last
- __first
;
567 return ranges::fill_n(__first
, __len
, __value
);
569 else if constexpr (is_scalar_v
<_Tp
>)
571 const auto __tmp
= __value
;
572 for (; __first
!= __last
; ++__first
)
578 for (; __first
!= __last
; ++__first
)
584 template<typename _Tp
, output_range
<const _Tp
&> _Range
>
585 constexpr borrowed_iterator_t
<_Range
>
586 operator()(_Range
&& __r
, const _Tp
& __value
) const
588 return (*this)(ranges::begin(__r
), ranges::end(__r
), __value
);
592 inline constexpr __fill_fn fill
{};
594 _GLIBCXX_END_NAMESPACE_VERSION
598 #endif // _RANGES_ALGOBASE_H