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1 | // Algorithm extensions -*- C++ -*- | |
2 | ||
3 | // Copyright (C) 2001-2023 Free Software Foundation, Inc. | |
4 | // | |
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) | |
9 | // any later version. | |
10 | ||
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. | |
15 | ||
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. | |
19 | ||
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/>. | |
24 | ||
25 | /* | |
26 | * | |
27 | * Copyright (c) 1994 | |
28 | * Hewlett-Packard Company | |
29 | * | |
30 | * Permission to use, copy, modify, distribute and sell this software | |
31 | * and its documentation for any purpose is hereby granted without fee, | |
32 | * provided that the above copyright notice appear in all copies and | |
33 | * that both that copyright notice and this permission notice appear | |
34 | * in supporting documentation. Hewlett-Packard Company makes no | |
35 | * representations about the suitability of this software for any | |
36 | * purpose. It is provided "as is" without express or implied warranty. | |
37 | * | |
38 | * | |
39 | * Copyright (c) 1996 | |
40 | * Silicon Graphics Computer Systems, Inc. | |
41 | * | |
42 | * Permission to use, copy, modify, distribute and sell this software | |
43 | * and its documentation for any purpose is hereby granted without fee, | |
44 | * provided that the above copyright notice appear in all copies and | |
45 | * that both that copyright notice and this permission notice appear | |
46 | * in supporting documentation. Silicon Graphics makes no | |
47 | * representations about the suitability of this software for any | |
48 | * purpose. It is provided "as is" without express or implied warranty. | |
49 | */ | |
50 | ||
51 | /** @file ext/algorithm | |
52 | * This file is a GNU extension to the Standard C++ Library (possibly | |
53 | * containing extensions from the HP/SGI STL subset). | |
54 | */ | |
55 | ||
56 | #ifndef _EXT_ALGORITHM | |
57 | #define _EXT_ALGORITHM 1 | |
58 | ||
59 | #pragma GCC system_header | |
60 | ||
61 | #include <bits/requires_hosted.h> // GNU extensions are currently omitted | |
62 | ||
63 | #include <algorithm> | |
64 | ||
65 | namespace __gnu_cxx _GLIBCXX_VISIBILITY(default) | |
66 | { | |
67 | _GLIBCXX_BEGIN_NAMESPACE_VERSION | |
68 | ||
69 | //-------------------------------------------------- | |
70 | // copy_n (not part of the C++ standard) | |
71 | ||
72 | template<typename _InputIterator, typename _Size, typename _OutputIterator> | |
73 | std::pair<_InputIterator, _OutputIterator> | |
74 | __copy_n(_InputIterator __first, _Size __count, | |
75 | _OutputIterator __result, | |
76 | std::input_iterator_tag) | |
77 | { | |
78 | for ( ; __count > 0; --__count) | |
79 | { | |
80 | *__result = *__first; | |
81 | ++__first; | |
82 | ++__result; | |
83 | } | |
84 | return std::pair<_InputIterator, _OutputIterator>(__first, __result); | |
85 | } | |
86 | ||
87 | template<typename _RAIterator, typename _Size, typename _OutputIterator> | |
88 | inline std::pair<_RAIterator, _OutputIterator> | |
89 | __copy_n(_RAIterator __first, _Size __count, | |
90 | _OutputIterator __result, | |
91 | std::random_access_iterator_tag) | |
92 | { | |
93 | _RAIterator __last = __first + __count; | |
94 | return std::pair<_RAIterator, _OutputIterator>(__last, std::copy(__first, | |
95 | __last, | |
96 | __result)); | |
97 | } | |
98 | ||
99 | /** | |
100 | * @brief Copies the range [first,first+count) into [result,result+count). | |
101 | * @param __first An input iterator. | |
102 | * @param __count The number of elements to copy. | |
103 | * @param __result An output iterator. | |
104 | * @return A std::pair composed of first+count and result+count. | |
105 | * | |
106 | * This is an SGI extension. | |
107 | * This inline function will boil down to a call to @c memmove whenever | |
108 | * possible. Failing that, if random access iterators are passed, then the | |
109 | * loop count will be known (and therefore a candidate for compiler | |
110 | * optimizations such as unrolling). | |
111 | * @ingroup SGIextensions | |
112 | */ | |
113 | template<typename _InputIterator, typename _Size, typename _OutputIterator> | |
114 | inline std::pair<_InputIterator, _OutputIterator> | |
115 | copy_n(_InputIterator __first, _Size __count, _OutputIterator __result) | |
116 | { | |
117 | // concept requirements | |
118 | __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>) | |
119 | __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator, | |
120 | typename std::iterator_traits<_InputIterator>::value_type>) | |
121 | ||
122 | return __gnu_cxx::__copy_n(__first, __count, __result, | |
123 | std::__iterator_category(__first)); | |
124 | } | |
125 | ||
126 | template<typename _InputIterator1, typename _InputIterator2> | |
127 | int | |
128 | __lexicographical_compare_3way(_InputIterator1 __first1, | |
129 | _InputIterator1 __last1, | |
130 | _InputIterator2 __first2, | |
131 | _InputIterator2 __last2) | |
132 | { | |
133 | while (__first1 != __last1 && __first2 != __last2) | |
134 | { | |
135 | if (*__first1 < *__first2) | |
136 | return -1; | |
137 | if (*__first2 < *__first1) | |
138 | return 1; | |
139 | ++__first1; | |
140 | ++__first2; | |
141 | } | |
142 | if (__first2 == __last2) | |
143 | return !(__first1 == __last1); | |
144 | else | |
145 | return -1; | |
146 | } | |
147 | ||
148 | inline int | |
149 | __lexicographical_compare_3way(const unsigned char* __first1, | |
150 | const unsigned char* __last1, | |
151 | const unsigned char* __first2, | |
152 | const unsigned char* __last2) | |
153 | { | |
154 | const std::ptrdiff_t __len1 = __last1 - __first1; | |
155 | const std::ptrdiff_t __len2 = __last2 - __first2; | |
156 | const int __result = __builtin_memcmp(__first1, __first2, | |
157 | (std::min)(__len1, __len2)); | |
158 | return __result != 0 ? __result | |
159 | : (__len1 == __len2 ? 0 : (__len1 < __len2 ? -1 : 1)); | |
160 | } | |
161 | ||
162 | inline int | |
163 | __lexicographical_compare_3way(const char* __first1, const char* __last1, | |
164 | const char* __first2, const char* __last2) | |
165 | { | |
166 | #if CHAR_MAX == SCHAR_MAX | |
167 | return __lexicographical_compare_3way((const signed char*) __first1, | |
168 | (const signed char*) __last1, | |
169 | (const signed char*) __first2, | |
170 | (const signed char*) __last2); | |
171 | #else | |
172 | return __lexicographical_compare_3way((const unsigned char*) __first1, | |
173 | (const unsigned char*) __last1, | |
174 | (const unsigned char*) __first2, | |
175 | (const unsigned char*) __last2); | |
176 | #endif | |
177 | } | |
178 | ||
179 | /** | |
180 | * @brief @c memcmp on steroids. | |
181 | * @param __first1 An input iterator. | |
182 | * @param __last1 An input iterator. | |
183 | * @param __first2 An input iterator. | |
184 | * @param __last2 An input iterator. | |
185 | * @return An int, as with @c memcmp. | |
186 | * | |
187 | * The return value will be less than zero if the first range is | |
188 | * <em>lexigraphically less than</em> the second, greater than zero | |
189 | * if the second range is <em>lexigraphically less than</em> the | |
190 | * first, and zero otherwise. | |
191 | * This is an SGI extension. | |
192 | * @ingroup SGIextensions | |
193 | */ | |
194 | template<typename _InputIterator1, typename _InputIterator2> | |
195 | int | |
196 | lexicographical_compare_3way(_InputIterator1 __first1, | |
197 | _InputIterator1 __last1, | |
198 | _InputIterator2 __first2, | |
199 | _InputIterator2 __last2) | |
200 | { | |
201 | // concept requirements | |
202 | __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>) | |
203 | __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>) | |
204 | __glibcxx_function_requires(_LessThanComparableConcept< | |
205 | typename std::iterator_traits<_InputIterator1>::value_type>) | |
206 | __glibcxx_function_requires(_LessThanComparableConcept< | |
207 | typename std::iterator_traits<_InputIterator2>::value_type>) | |
208 | __glibcxx_requires_valid_range(__first1, __last1); | |
209 | __glibcxx_requires_valid_range(__first2, __last2); | |
210 | ||
211 | return __lexicographical_compare_3way(__first1, __last1, __first2, | |
212 | __last2); | |
213 | } | |
214 | ||
215 | // count and count_if: this version, whose return type is void, was present | |
216 | // in the HP STL, and is retained as an extension for backward compatibility. | |
217 | template<typename _InputIterator, typename _Tp, typename _Size> | |
218 | void | |
219 | count(_InputIterator __first, _InputIterator __last, | |
220 | const _Tp& __value, | |
221 | _Size& __n) | |
222 | { | |
223 | // concept requirements | |
224 | __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>) | |
225 | __glibcxx_function_requires(_EqualityComparableConcept< | |
226 | typename std::iterator_traits<_InputIterator>::value_type >) | |
227 | __glibcxx_function_requires(_EqualityComparableConcept<_Tp>) | |
228 | __glibcxx_requires_valid_range(__first, __last); | |
229 | ||
230 | for ( ; __first != __last; ++__first) | |
231 | if (*__first == __value) | |
232 | ++__n; | |
233 | } | |
234 | ||
235 | template<typename _InputIterator, typename _Predicate, typename _Size> | |
236 | void | |
237 | count_if(_InputIterator __first, _InputIterator __last, | |
238 | _Predicate __pred, | |
239 | _Size& __n) | |
240 | { | |
241 | // concept requirements | |
242 | __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>) | |
243 | __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate, | |
244 | typename std::iterator_traits<_InputIterator>::value_type>) | |
245 | __glibcxx_requires_valid_range(__first, __last); | |
246 | ||
247 | for ( ; __first != __last; ++__first) | |
248 | if (__pred(*__first)) | |
249 | ++__n; | |
250 | } | |
251 | ||
252 | // random_sample and random_sample_n (extensions, not part of the standard). | |
253 | ||
254 | /** | |
255 | * This is an SGI extension. | |
256 | * @ingroup SGIextensions | |
257 | * @doctodo | |
258 | */ | |
259 | template<typename _ForwardIterator, typename _OutputIterator, | |
260 | typename _Distance> | |
261 | _OutputIterator | |
262 | random_sample_n(_ForwardIterator __first, _ForwardIterator __last, | |
263 | _OutputIterator __out, const _Distance __n) | |
264 | { | |
265 | // concept requirements | |
266 | __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>) | |
267 | __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator, | |
268 | typename std::iterator_traits<_ForwardIterator>::value_type>) | |
269 | __glibcxx_requires_valid_range(__first, __last); | |
270 | ||
271 | _Distance __remaining = std::distance(__first, __last); | |
272 | _Distance __m = (std::min)(__n, __remaining); | |
273 | ||
274 | while (__m > 0) | |
275 | { | |
276 | if ((std::rand() % __remaining) < __m) | |
277 | { | |
278 | *__out = *__first; | |
279 | ++__out; | |
280 | --__m; | |
281 | } | |
282 | --__remaining; | |
283 | ++__first; | |
284 | } | |
285 | return __out; | |
286 | } | |
287 | ||
288 | /** | |
289 | * This is an SGI extension. | |
290 | * @ingroup SGIextensions | |
291 | * @doctodo | |
292 | */ | |
293 | template<typename _ForwardIterator, typename _OutputIterator, | |
294 | typename _Distance, typename _RandomNumberGenerator> | |
295 | _OutputIterator | |
296 | random_sample_n(_ForwardIterator __first, _ForwardIterator __last, | |
297 | _OutputIterator __out, const _Distance __n, | |
298 | _RandomNumberGenerator& __rand) | |
299 | { | |
300 | // concept requirements | |
301 | __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>) | |
302 | __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator, | |
303 | typename std::iterator_traits<_ForwardIterator>::value_type>) | |
304 | __glibcxx_function_requires(_UnaryFunctionConcept< | |
305 | _RandomNumberGenerator, _Distance, _Distance>) | |
306 | __glibcxx_requires_valid_range(__first, __last); | |
307 | ||
308 | _Distance __remaining = std::distance(__first, __last); | |
309 | _Distance __m = (std::min)(__n, __remaining); | |
310 | ||
311 | while (__m > 0) | |
312 | { | |
313 | if (__rand(__remaining) < __m) | |
314 | { | |
315 | *__out = *__first; | |
316 | ++__out; | |
317 | --__m; | |
318 | } | |
319 | --__remaining; | |
320 | ++__first; | |
321 | } | |
322 | return __out; | |
323 | } | |
324 | ||
325 | template<typename _InputIterator, typename _RandomAccessIterator, | |
326 | typename _Distance> | |
327 | _RandomAccessIterator | |
328 | __random_sample(_InputIterator __first, _InputIterator __last, | |
329 | _RandomAccessIterator __out, | |
330 | const _Distance __n) | |
331 | { | |
332 | _Distance __m = 0; | |
333 | _Distance __t = __n; | |
334 | for ( ; __first != __last && __m < __n; ++__m, ++__first) | |
335 | __out[__m] = *__first; | |
336 | ||
337 | while (__first != __last) | |
338 | { | |
339 | ++__t; | |
340 | _Distance __M = std::rand() % (__t); | |
341 | if (__M < __n) | |
342 | __out[__M] = *__first; | |
343 | ++__first; | |
344 | } | |
345 | return __out + __m; | |
346 | } | |
347 | ||
348 | template<typename _InputIterator, typename _RandomAccessIterator, | |
349 | typename _RandomNumberGenerator, typename _Distance> | |
350 | _RandomAccessIterator | |
351 | __random_sample(_InputIterator __first, _InputIterator __last, | |
352 | _RandomAccessIterator __out, | |
353 | _RandomNumberGenerator& __rand, | |
354 | const _Distance __n) | |
355 | { | |
356 | // concept requirements | |
357 | __glibcxx_function_requires(_UnaryFunctionConcept< | |
358 | _RandomNumberGenerator, _Distance, _Distance>) | |
359 | ||
360 | _Distance __m = 0; | |
361 | _Distance __t = __n; | |
362 | for ( ; __first != __last && __m < __n; ++__m, ++__first) | |
363 | __out[__m] = *__first; | |
364 | ||
365 | while (__first != __last) | |
366 | { | |
367 | ++__t; | |
368 | _Distance __M = __rand(__t); | |
369 | if (__M < __n) | |
370 | __out[__M] = *__first; | |
371 | ++__first; | |
372 | } | |
373 | return __out + __m; | |
374 | } | |
375 | ||
376 | /** | |
377 | * This is an SGI extension. | |
378 | * @ingroup SGIextensions | |
379 | * @doctodo | |
380 | */ | |
381 | template<typename _InputIterator, typename _RandomAccessIterator> | |
382 | inline _RandomAccessIterator | |
383 | random_sample(_InputIterator __first, _InputIterator __last, | |
384 | _RandomAccessIterator __out_first, | |
385 | _RandomAccessIterator __out_last) | |
386 | { | |
387 | // concept requirements | |
388 | __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>) | |
389 | __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept< | |
390 | _RandomAccessIterator>) | |
391 | __glibcxx_requires_valid_range(__first, __last); | |
392 | __glibcxx_requires_valid_range(__out_first, __out_last); | |
393 | ||
394 | return __random_sample(__first, __last, | |
395 | __out_first, __out_last - __out_first); | |
396 | } | |
397 | ||
398 | /** | |
399 | * This is an SGI extension. | |
400 | * @ingroup SGIextensions | |
401 | * @doctodo | |
402 | */ | |
403 | template<typename _InputIterator, typename _RandomAccessIterator, | |
404 | typename _RandomNumberGenerator> | |
405 | inline _RandomAccessIterator | |
406 | random_sample(_InputIterator __first, _InputIterator __last, | |
407 | _RandomAccessIterator __out_first, | |
408 | _RandomAccessIterator __out_last, | |
409 | _RandomNumberGenerator& __rand) | |
410 | { | |
411 | // concept requirements | |
412 | __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>) | |
413 | __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept< | |
414 | _RandomAccessIterator>) | |
415 | __glibcxx_requires_valid_range(__first, __last); | |
416 | __glibcxx_requires_valid_range(__out_first, __out_last); | |
417 | ||
418 | return __random_sample(__first, __last, | |
419 | __out_first, __rand, | |
420 | __out_last - __out_first); | |
421 | } | |
422 | ||
423 | #if __cplusplus >= 201103L | |
424 | using std::is_heap; | |
425 | #else | |
426 | /** | |
427 | * This is an SGI extension. | |
428 | * @ingroup SGIextensions | |
429 | * @doctodo | |
430 | */ | |
431 | template<typename _RandomAccessIterator> | |
432 | inline bool | |
433 | is_heap(_RandomAccessIterator __first, _RandomAccessIterator __last) | |
434 | { | |
435 | // concept requirements | |
436 | __glibcxx_function_requires(_RandomAccessIteratorConcept< | |
437 | _RandomAccessIterator>) | |
438 | __glibcxx_function_requires(_LessThanComparableConcept< | |
439 | typename std::iterator_traits<_RandomAccessIterator>::value_type>) | |
440 | __glibcxx_requires_valid_range(__first, __last); | |
441 | ||
442 | return std::__is_heap(__first, __last - __first); | |
443 | } | |
444 | ||
445 | /** | |
446 | * This is an SGI extension. | |
447 | * @ingroup SGIextensions | |
448 | * @doctodo | |
449 | */ | |
450 | template<typename _RandomAccessIterator, typename _StrictWeakOrdering> | |
451 | inline bool | |
452 | is_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, | |
453 | _StrictWeakOrdering __comp) | |
454 | { | |
455 | // concept requirements | |
456 | __glibcxx_function_requires(_RandomAccessIteratorConcept< | |
457 | _RandomAccessIterator>) | |
458 | __glibcxx_function_requires(_BinaryPredicateConcept<_StrictWeakOrdering, | |
459 | typename std::iterator_traits<_RandomAccessIterator>::value_type, | |
460 | typename std::iterator_traits<_RandomAccessIterator>::value_type>) | |
461 | __glibcxx_requires_valid_range(__first, __last); | |
462 | ||
463 | return std::__is_heap(__first, __comp, __last - __first); | |
464 | } | |
465 | #endif | |
466 | ||
467 | #if __cplusplus >= 201103L | |
468 | using std::is_sorted; | |
469 | #else | |
470 | // is_sorted, a predicated testing whether a range is sorted in | |
471 | // nondescending order. This is an extension, not part of the C++ | |
472 | // standard. | |
473 | ||
474 | /** | |
475 | * This is an SGI extension. | |
476 | * @ingroup SGIextensions | |
477 | * @doctodo | |
478 | */ | |
479 | template<typename _ForwardIterator> | |
480 | bool | |
481 | is_sorted(_ForwardIterator __first, _ForwardIterator __last) | |
482 | { | |
483 | // concept requirements | |
484 | __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>) | |
485 | __glibcxx_function_requires(_LessThanComparableConcept< | |
486 | typename std::iterator_traits<_ForwardIterator>::value_type>) | |
487 | __glibcxx_requires_valid_range(__first, __last); | |
488 | ||
489 | if (__first == __last) | |
490 | return true; | |
491 | ||
492 | _ForwardIterator __next = __first; | |
493 | for (++__next; __next != __last; __first = __next, ++__next) | |
494 | if (*__next < *__first) | |
495 | return false; | |
496 | return true; | |
497 | } | |
498 | ||
499 | /** | |
500 | * This is an SGI extension. | |
501 | * @ingroup SGIextensions | |
502 | * @doctodo | |
503 | */ | |
504 | template<typename _ForwardIterator, typename _StrictWeakOrdering> | |
505 | bool | |
506 | is_sorted(_ForwardIterator __first, _ForwardIterator __last, | |
507 | _StrictWeakOrdering __comp) | |
508 | { | |
509 | // concept requirements | |
510 | __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>) | |
511 | __glibcxx_function_requires(_BinaryPredicateConcept<_StrictWeakOrdering, | |
512 | typename std::iterator_traits<_ForwardIterator>::value_type, | |
513 | typename std::iterator_traits<_ForwardIterator>::value_type>) | |
514 | __glibcxx_requires_valid_range(__first, __last); | |
515 | ||
516 | if (__first == __last) | |
517 | return true; | |
518 | ||
519 | _ForwardIterator __next = __first; | |
520 | for (++__next; __next != __last; __first = __next, ++__next) | |
521 | if (__comp(*__next, *__first)) | |
522 | return false; | |
523 | return true; | |
524 | } | |
525 | #endif // C++11 | |
526 | ||
527 | /** | |
528 | * @brief Find the median of three values. | |
529 | * @param __a A value. | |
530 | * @param __b A value. | |
531 | * @param __c A value. | |
532 | * @return One of @p a, @p b or @p c. | |
533 | * | |
534 | * If @c {l,m,n} is some convolution of @p {a,b,c} such that @c l<=m<=n | |
535 | * then the value returned will be @c m. | |
536 | * This is an SGI extension. | |
537 | * @ingroup SGIextensions | |
538 | */ | |
539 | template<typename _Tp> | |
540 | const _Tp& | |
541 | __median(const _Tp& __a, const _Tp& __b, const _Tp& __c) | |
542 | { | |
543 | // concept requirements | |
544 | __glibcxx_function_requires(_LessThanComparableConcept<_Tp>) | |
545 | if (__a < __b) | |
546 | if (__b < __c) | |
547 | return __b; | |
548 | else if (__a < __c) | |
549 | return __c; | |
550 | else | |
551 | return __a; | |
552 | else if (__a < __c) | |
553 | return __a; | |
554 | else if (__b < __c) | |
555 | return __c; | |
556 | else | |
557 | return __b; | |
558 | } | |
559 | ||
560 | /** | |
561 | * @brief Find the median of three values using a predicate for comparison. | |
562 | * @param __a A value. | |
563 | * @param __b A value. | |
564 | * @param __c A value. | |
565 | * @param __comp A binary predicate. | |
566 | * @return One of @p a, @p b or @p c. | |
567 | * | |
568 | * If @c {l,m,n} is some convolution of @p {a,b,c} such that @p comp(l,m) | |
569 | * and @p comp(m,n) are both true then the value returned will be @c m. | |
570 | * This is an SGI extension. | |
571 | * @ingroup SGIextensions | |
572 | */ | |
573 | template<typename _Tp, typename _Compare> | |
574 | const _Tp& | |
575 | __median(const _Tp& __a, const _Tp& __b, const _Tp& __c, _Compare __comp) | |
576 | { | |
577 | // concept requirements | |
578 | __glibcxx_function_requires(_BinaryFunctionConcept<_Compare, bool, | |
579 | _Tp, _Tp>) | |
580 | if (__comp(__a, __b)) | |
581 | if (__comp(__b, __c)) | |
582 | return __b; | |
583 | else if (__comp(__a, __c)) | |
584 | return __c; | |
585 | else | |
586 | return __a; | |
587 | else if (__comp(__a, __c)) | |
588 | return __a; | |
589 | else if (__comp(__b, __c)) | |
590 | return __c; | |
591 | else | |
592 | return __b; | |
593 | } | |
594 | ||
595 | _GLIBCXX_END_NAMESPACE_VERSION | |
596 | } // namespace | |
597 | ||
598 | #endif /* _EXT_ALGORITHM */ |