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1 | // Algorithm extensions -*- C++ -*- |
2 | ||
3 | // Copyright (C) 2001 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 2, 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 | // You should have received a copy of the GNU General Public License along | |
17 | // with this library; see the file COPYING. If not, write to the Free | |
18 | // Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, | |
19 | // USA. | |
20 | ||
21 | // As a special exception, you may use this file as part of a free software | |
22 | // library without restriction. Specifically, if other files instantiate | |
23 | // templates or use macros or inline functions from this file, or you compile | |
24 | // this file and link it with other files to produce an executable, this | |
25 | // file does not by itself cause the resulting executable to be covered by | |
26 | // the GNU General Public License. This exception does not however | |
27 | // invalidate any other reasons why the executable file might be covered by | |
28 | // the GNU General Public License. | |
29 | ||
30 | /* | |
31 | * | |
32 | * Copyright (c) 1994 | |
33 | * Hewlett-Packard Company | |
34 | * | |
35 | * Permission to use, copy, modify, distribute and sell this software | |
36 | * and its documentation for any purpose is hereby granted without fee, | |
37 | * provided that the above copyright notice appear in all copies and | |
38 | * that both that copyright notice and this permission notice appear | |
39 | * in supporting documentation. Hewlett-Packard Company makes no | |
40 | * representations about the suitability of this software for any | |
41 | * purpose. It is provided "as is" without express or implied warranty. | |
42 | * | |
43 | * | |
44 | * Copyright (c) 1996 | |
45 | * Silicon Graphics Computer Systems, Inc. | |
46 | * | |
47 | * Permission to use, copy, modify, distribute and sell this software | |
48 | * and its documentation for any purpose is hereby granted without fee, | |
49 | * provided that the above copyright notice appear in all copies and | |
50 | * that both that copyright notice and this permission notice appear | |
51 | * in supporting documentation. Silicon Graphics makes no | |
52 | * representations about the suitability of this software for any | |
53 | * purpose. It is provided "as is" without express or implied warranty. | |
54 | */ | |
55 | ||
56 | #ifndef _EXT_ALGORITHM | |
57 | #define _EXT_ALGORITHM | |
58 | ||
36955a95 | 59 | #pragma GCC system_header |
54c1bf78 | 60 | #include <algorithm> |
2c1bc4eb PC |
61 | |
62 | namespace __gnu_cxx | |
63 | { | |
f53d0ff1 PC |
64 | using std::ptrdiff_t; |
65 | using std::min; | |
66 | using std::pair; | |
67 | using std::input_iterator_tag; | |
68 | using std::random_access_iterator_tag; | |
69 | using std::iterator_traits; | |
70 | ||
71 | //-------------------------------------------------- | |
72 | // copy_n (not part of the C++ standard) | |
73 | ||
74 | template<typename _InputIter, typename _Size, typename _OutputIter> | |
75 | pair<_InputIter, _OutputIter> | |
76 | __copy_n(_InputIter __first, _Size __count, | |
77 | _OutputIter __result, | |
78 | input_iterator_tag) | |
79 | { | |
80 | for ( ; __count > 0; --__count) { | |
81 | *__result = *__first; | |
82 | ++__first; | |
83 | ++__result; | |
84 | } | |
85 | return pair<_InputIter, _OutputIter>(__first, __result); | |
86 | } | |
87 | ||
88 | template<typename _RAIter, typename _Size, typename _OutputIter> | |
89 | inline pair<_RAIter, _OutputIter> | |
90 | __copy_n(_RAIter __first, _Size __count, | |
91 | _OutputIter __result, | |
92 | random_access_iterator_tag) | |
93 | { | |
94 | _RAIter __last = __first + __count; | |
95 | return pair<_RAIter, _OutputIter>(__last, | |
96 | std::copy(__first, __last, __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 _InputIter, typename _Size, typename _OutputIter> | |
114 | inline pair<_InputIter, _OutputIter> | |
115 | copy_n(_InputIter __first, _Size __count, _OutputIter __result) | |
116 | { | |
117 | // concept requirements | |
118 | __glibcpp_function_requires(_InputIteratorConcept<_InputIter>) | |
119 | __glibcpp_function_requires(_OutputIteratorConcept<_OutputIter, | |
120 | typename iterator_traits<_InputIter>::value_type>) | |
121 | ||
122 | return __copy_n(__first, __count, __result, | |
123 | std::__iterator_category(__first)); | |
124 | } | |
125 | ||
126 | template<typename _InputIter1, typename _InputIter2> | |
127 | int | |
128 | __lexicographical_compare_3way(_InputIter1 __first1, _InputIter1 __last1, | |
129 | _InputIter2 __first2, _InputIter2 __last2) | |
130 | { | |
131 | while (__first1 != __last1 && __first2 != __last2) { | |
132 | if (*__first1 < *__first2) | |
133 | return -1; | |
134 | if (*__first2 < *__first1) | |
135 | return 1; | |
136 | ++__first1; | |
137 | ++__first2; | |
138 | } | |
139 | if (__first2 == __last2) { | |
140 | return !(__first1 == __last1); | |
141 | } | |
142 | else { | |
143 | return -1; | |
144 | } | |
145 | } | |
146 | ||
147 | inline int | |
148 | __lexicographical_compare_3way(const unsigned char* __first1, | |
149 | const unsigned char* __last1, | |
150 | const unsigned char* __first2, | |
151 | const unsigned char* __last2) | |
152 | { | |
153 | const ptrdiff_t __len1 = __last1 - __first1; | |
154 | const ptrdiff_t __len2 = __last2 - __first2; | |
155 | const int __result = std::memcmp(__first1, __first2, min(__len1, __len2)); | |
156 | return __result != 0 ? __result | |
157 | : (__len1 == __len2 ? 0 : (__len1 < __len2 ? -1 : 1)); | |
158 | } | |
159 | ||
160 | inline int | |
161 | __lexicographical_compare_3way(const char* __first1, const char* __last1, | |
162 | const char* __first2, const char* __last2) | |
163 | { | |
164 | #if CHAR_MAX == SCHAR_MAX | |
165 | return __lexicographical_compare_3way( | |
166 | (const signed char*) __first1, | |
167 | (const signed char*) __last1, | |
168 | (const signed char*) __first2, | |
169 | (const signed char*) __last2); | |
170 | #else | |
171 | return __lexicographical_compare_3way((const unsigned char*) __first1, | |
172 | (const unsigned char*) __last1, | |
173 | (const unsigned char*) __first2, | |
174 | (const unsigned char*) __last2); | |
175 | #endif | |
176 | } | |
177 | ||
178 | /** | |
179 | * @brief @c memcmp on steroids. | |
180 | * @param first1 An input iterator. | |
181 | * @param last1 An input iterator. | |
182 | * @param first2 An input iterator. | |
183 | * @param last2 An input iterator. | |
184 | * @return An int, as with @c memcmp. | |
185 | * | |
186 | * The return value will be less than zero if the first range is | |
187 | * "lexigraphically less than" the second, greater than zero if the second | |
188 | * range is "lexigraphically less than" the first, and zero otherwise. | |
189 | * This is an SGI extension. | |
190 | * @ingroup SGIextensions | |
191 | */ | |
192 | template<typename _InputIter1, typename _InputIter2> | |
193 | int | |
194 | lexicographical_compare_3way(_InputIter1 __first1, _InputIter1 __last1, | |
195 | _InputIter2 __first2, _InputIter2 __last2) | |
196 | { | |
197 | // concept requirements | |
198 | __glibcpp_function_requires(_InputIteratorConcept<_InputIter1>) | |
199 | __glibcpp_function_requires(_InputIteratorConcept<_InputIter2>) | |
200 | __glibcpp_function_requires(_LessThanComparableConcept< | |
201 | typename iterator_traits<_InputIter1>::value_type>) | |
202 | __glibcpp_function_requires(_LessThanComparableConcept< | |
203 | typename iterator_traits<_InputIter2>::value_type>) | |
204 | ||
205 | return __lexicographical_compare_3way(__first1, __last1, __first2, __last2); | |
206 | } | |
207 | ||
2c1bc4eb PC |
208 | // count and count_if: this version, whose return type is void, was present |
209 | // in the HP STL, and is retained as an extension for backward compatibility. | |
210 | ||
211 | template<typename _InputIter, typename _Tp, typename _Size> | |
212 | void | |
213 | count(_InputIter __first, _InputIter __last, | |
214 | const _Tp& __value, | |
215 | _Size& __n) | |
216 | { | |
217 | // concept requirements | |
218 | __glibcpp_function_requires(_InputIteratorConcept<_InputIter>) | |
219 | __glibcpp_function_requires(_EqualityComparableConcept< | |
f53d0ff1 | 220 | typename iterator_traits<_InputIter>::value_type >) |
2c1bc4eb PC |
221 | __glibcpp_function_requires(_EqualityComparableConcept<_Tp>) |
222 | for ( ; __first != __last; ++__first) | |
223 | if (*__first == __value) | |
224 | ++__n; | |
225 | } | |
226 | ||
227 | template<typename _InputIter, typename _Predicate, typename _Size> | |
228 | void | |
229 | count_if(_InputIter __first, _InputIter __last, | |
230 | _Predicate __pred, | |
231 | _Size& __n) | |
232 | { | |
233 | // concept requirements | |
234 | __glibcpp_function_requires(_InputIteratorConcept<_InputIter>) | |
235 | __glibcpp_function_requires(_UnaryPredicateConcept<_Predicate, | |
f53d0ff1 | 236 | typename iterator_traits<_InputIter>::value_type>) |
2c1bc4eb PC |
237 | for ( ; __first != __last; ++__first) |
238 | if (__pred(*__first)) | |
239 | ++__n; | |
240 | } | |
241 | ||
242 | // random_sample and random_sample_n (extensions, not part of the standard). | |
243 | ||
244 | template<typename _ForwardIter, typename _OutputIter, typename _Distance> | |
245 | _OutputIter | |
246 | random_sample_n(_ForwardIter __first, _ForwardIter __last, | |
247 | _OutputIter __out, const _Distance __n) | |
248 | { | |
249 | // concept requirements | |
250 | __glibcpp_function_requires(_ForwardIteratorConcept<_ForwardIter>) | |
251 | __glibcpp_function_requires(_OutputIteratorConcept<_OutputIter, | |
f53d0ff1 | 252 | typename iterator_traits<_ForwardIter>::value_type>) |
2c1bc4eb PC |
253 | |
254 | _Distance __remaining = std::distance(__first, __last); | |
f53d0ff1 | 255 | _Distance __m = min(__n, __remaining); |
2c1bc4eb PC |
256 | |
257 | while (__m > 0) { | |
258 | if (std::__random_number(__remaining) < __m) { | |
259 | *__out = *__first; | |
260 | ++__out; | |
261 | --__m; | |
262 | } | |
263 | ||
264 | --__remaining; | |
265 | ++__first; | |
266 | } | |
267 | return __out; | |
268 | } | |
269 | ||
270 | template<typename _ForwardIter, typename _OutputIter, typename _Distance, | |
271 | typename _RandomNumberGenerator> | |
272 | _OutputIter | |
273 | random_sample_n(_ForwardIter __first, _ForwardIter __last, | |
274 | _OutputIter __out, const _Distance __n, | |
275 | _RandomNumberGenerator& __rand) | |
276 | { | |
277 | // concept requirements | |
278 | __glibcpp_function_requires(_ForwardIteratorConcept<_ForwardIter>) | |
279 | __glibcpp_function_requires(_OutputIteratorConcept<_OutputIter, | |
f53d0ff1 | 280 | typename iterator_traits<_ForwardIter>::value_type>) |
2c1bc4eb PC |
281 | __glibcpp_function_requires(_UnaryFunctionConcept< |
282 | _RandomNumberGenerator, _Distance, _Distance>) | |
283 | ||
284 | _Distance __remaining = std::distance(__first, __last); | |
f53d0ff1 | 285 | _Distance __m = min(__n, __remaining); |
2c1bc4eb PC |
286 | |
287 | while (__m > 0) { | |
288 | if (__rand(__remaining) < __m) { | |
289 | *__out = *__first; | |
290 | ++__out; | |
291 | --__m; | |
292 | } | |
293 | ||
294 | --__remaining; | |
295 | ++__first; | |
296 | } | |
297 | return __out; | |
298 | } | |
299 | ||
300 | template<typename _InputIter, typename _RandomAccessIter, typename _Distance> | |
301 | _RandomAccessIter | |
302 | __random_sample(_InputIter __first, _InputIter __last, | |
303 | _RandomAccessIter __out, | |
304 | const _Distance __n) | |
305 | { | |
306 | _Distance __m = 0; | |
307 | _Distance __t = __n; | |
308 | for ( ; __first != __last && __m < __n; ++__m, ++__first) | |
309 | __out[__m] = *__first; | |
310 | ||
311 | while (__first != __last) { | |
312 | ++__t; | |
313 | _Distance __M = std::__random_number(__t); | |
314 | if (__M < __n) | |
315 | __out[__M] = *__first; | |
316 | ++__first; | |
317 | } | |
318 | ||
319 | return __out + __m; | |
320 | } | |
321 | ||
322 | template<typename _InputIter, typename _RandomAccessIter, | |
323 | typename _RandomNumberGenerator, typename _Distance> | |
324 | _RandomAccessIter | |
325 | __random_sample(_InputIter __first, _InputIter __last, | |
326 | _RandomAccessIter __out, | |
327 | _RandomNumberGenerator& __rand, | |
328 | const _Distance __n) | |
329 | { | |
330 | // concept requirements | |
331 | __glibcpp_function_requires(_UnaryFunctionConcept< | |
332 | _RandomNumberGenerator, _Distance, _Distance>) | |
333 | ||
334 | _Distance __m = 0; | |
335 | _Distance __t = __n; | |
336 | for ( ; __first != __last && __m < __n; ++__m, ++__first) | |
337 | __out[__m] = *__first; | |
338 | ||
339 | while (__first != __last) { | |
340 | ++__t; | |
341 | _Distance __M = __rand(__t); | |
342 | if (__M < __n) | |
343 | __out[__M] = *__first; | |
344 | ++__first; | |
345 | } | |
346 | ||
347 | return __out + __m; | |
348 | } | |
349 | ||
350 | template<typename _InputIter, typename _RandomAccessIter> | |
351 | inline _RandomAccessIter | |
352 | random_sample(_InputIter __first, _InputIter __last, | |
353 | _RandomAccessIter __out_first, _RandomAccessIter __out_last) | |
354 | { | |
355 | // concept requirements | |
356 | __glibcpp_function_requires(_InputIteratorConcept<_InputIter>) | |
357 | __glibcpp_function_requires(_Mutable_RandomAccessIteratorConcept< | |
358 | _RandomAccessIter>) | |
359 | ||
360 | return __random_sample(__first, __last, | |
361 | __out_first, __out_last - __out_first); | |
362 | } | |
363 | ||
364 | template<typename _InputIter, typename _RandomAccessIter, | |
365 | typename _RandomNumberGenerator> | |
366 | inline _RandomAccessIter | |
367 | random_sample(_InputIter __first, _InputIter __last, | |
368 | _RandomAccessIter __out_first, _RandomAccessIter __out_last, | |
369 | _RandomNumberGenerator& __rand) | |
370 | { | |
371 | // concept requirements | |
372 | __glibcpp_function_requires(_InputIteratorConcept<_InputIter>) | |
373 | __glibcpp_function_requires(_Mutable_RandomAccessIteratorConcept< | |
374 | _RandomAccessIter>) | |
375 | ||
376 | return __random_sample(__first, __last, | |
377 | __out_first, __rand, | |
378 | __out_last - __out_first); | |
379 | } | |
380 | ||
381 | // is_heap, a predicate testing whether or not a range is | |
382 | // a heap. This function is an extension, not part of the C++ | |
383 | // standard. | |
384 | ||
385 | template<typename _RandomAccessIter, typename _Distance> | |
386 | bool | |
387 | __is_heap(_RandomAccessIter __first, _Distance __n) | |
388 | { | |
389 | _Distance __parent = 0; | |
390 | for (_Distance __child = 1; __child < __n; ++__child) { | |
391 | if (__first[__parent] < __first[__child]) | |
392 | return false; | |
393 | if ((__child & 1) == 0) | |
394 | ++__parent; | |
395 | } | |
396 | return true; | |
397 | } | |
398 | ||
399 | template<typename _RandomAccessIter, typename _Distance, | |
400 | typename _StrictWeakOrdering> | |
401 | bool | |
402 | __is_heap(_RandomAccessIter __first, _StrictWeakOrdering __comp, | |
403 | _Distance __n) | |
404 | { | |
405 | _Distance __parent = 0; | |
406 | for (_Distance __child = 1; __child < __n; ++__child) { | |
407 | if (__comp(__first[__parent], __first[__child])) | |
408 | return false; | |
409 | if ((__child & 1) == 0) | |
410 | ++__parent; | |
411 | } | |
412 | return true; | |
413 | } | |
414 | ||
415 | template<typename _RandomAccessIter> | |
416 | inline bool | |
417 | is_heap(_RandomAccessIter __first, _RandomAccessIter __last) | |
418 | { | |
419 | // concept requirements | |
420 | __glibcpp_function_requires(_RandomAccessIteratorConcept<_RandomAccessIter>) | |
421 | __glibcpp_function_requires(_LessThanComparableConcept< | |
f53d0ff1 | 422 | typename iterator_traits<_RandomAccessIter>::value_type>) |
2c1bc4eb PC |
423 | |
424 | return __is_heap(__first, __last - __first); | |
425 | } | |
426 | ||
427 | template<typename _RandomAccessIter, typename _StrictWeakOrdering> | |
428 | inline bool | |
429 | is_heap(_RandomAccessIter __first, _RandomAccessIter __last, | |
430 | _StrictWeakOrdering __comp) | |
431 | { | |
432 | // concept requirements | |
433 | __glibcpp_function_requires(_RandomAccessIteratorConcept<_RandomAccessIter>) | |
434 | __glibcpp_function_requires(_BinaryPredicateConcept<_StrictWeakOrdering, | |
f53d0ff1 PC |
435 | typename iterator_traits<_RandomAccessIter>::value_type, |
436 | typename iterator_traits<_RandomAccessIter>::value_type>) | |
2c1bc4eb PC |
437 | |
438 | return __is_heap(__first, __comp, __last - __first); | |
439 | } | |
440 | ||
441 | // is_sorted, a predicated testing whether a range is sorted in | |
442 | // nondescending order. This is an extension, not part of the C++ | |
443 | // standard. | |
444 | ||
445 | template<typename _ForwardIter> | |
446 | bool | |
447 | is_sorted(_ForwardIter __first, _ForwardIter __last) | |
448 | { | |
449 | // concept requirements | |
450 | __glibcpp_function_requires(_ForwardIteratorConcept<_ForwardIter>) | |
451 | __glibcpp_function_requires(_LessThanComparableConcept< | |
f53d0ff1 | 452 | typename iterator_traits<_ForwardIter>::value_type>) |
2c1bc4eb PC |
453 | |
454 | if (__first == __last) | |
455 | return true; | |
456 | ||
457 | _ForwardIter __next = __first; | |
458 | for (++__next; __next != __last; __first = __next, ++__next) { | |
459 | if (*__next < *__first) | |
460 | return false; | |
461 | } | |
462 | ||
463 | return true; | |
464 | } | |
465 | ||
466 | template<typename _ForwardIter, typename _StrictWeakOrdering> | |
467 | bool | |
468 | is_sorted(_ForwardIter __first, _ForwardIter __last, _StrictWeakOrdering __comp) | |
469 | { | |
470 | // concept requirements | |
471 | __glibcpp_function_requires(_ForwardIteratorConcept<_ForwardIter>) | |
472 | __glibcpp_function_requires(_BinaryPredicateConcept<_StrictWeakOrdering, | |
f53d0ff1 PC |
473 | typename iterator_traits<_ForwardIter>::value_type, |
474 | typename iterator_traits<_ForwardIter>::value_type>) | |
2c1bc4eb PC |
475 | |
476 | if (__first == __last) | |
477 | return true; | |
478 | ||
479 | _ForwardIter __next = __first; | |
480 | for (++__next; __next != __last; __first = __next, ++__next) { | |
481 | if (__comp(*__next, *__first)) | |
482 | return false; | |
483 | } | |
484 | ||
485 | return true; | |
486 | } | |
487 | ||
488 | } // namespace __gnu_cxx | |
489 | ||
490 | #endif /* _EXT_ALGORITHM */ |