1 // Algorithm extensions -*- C++ -*-
3 // Copyright (C) 2001 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 2, 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 // 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,
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.
33 * Hewlett-Packard Company
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
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40 * representations about the suitability of this software for any
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45 * Silicon Graphics Computer Systems, Inc.
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
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53 * purpose. It is provided "as is" without express or implied warranty.
56 #ifndef _EXT_ALGORITHM
57 #define _EXT_ALGORITHM
59 #pragma GCC system_header
67 using std::input_iterator_tag;
68 using std::random_access_iterator_tag;
69 using std::iterator_traits;
71 //--------------------------------------------------
72 // copy_n (not part of the C++ standard)
74 template<typename _InputIter, typename _Size, typename _OutputIter>
75 pair<_InputIter, _OutputIter>
76 __copy_n(_InputIter __first, _Size __count,
80 for ( ; __count > 0; --__count) {
85 return pair<_InputIter, _OutputIter>(__first, __result);
88 template<typename _RAIter, typename _Size, typename _OutputIter>
89 inline pair<_RAIter, _OutputIter>
90 __copy_n(_RAIter __first, _Size __count,
92 random_access_iterator_tag)
94 _RAIter __last = __first + __count;
95 return pair<_RAIter, _OutputIter>(__last,
96 std::copy(__first, __last, __result));
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.
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
113 template<typename _InputIter, typename _Size, typename _OutputIter>
114 inline pair<_InputIter, _OutputIter>
115 copy_n(_InputIter __first, _Size __count, _OutputIter __result)
117 // concept requirements
118 __glibcpp_function_requires(_InputIteratorConcept<_InputIter>)
119 __glibcpp_function_requires(_OutputIteratorConcept<_OutputIter,
120 typename iterator_traits<_InputIter>::value_type>)
122 return __copy_n(__first, __count, __result,
123 std::__iterator_category(__first));
126 template<typename _InputIter1, typename _InputIter2>
128 __lexicographical_compare_3way(_InputIter1 __first1, _InputIter1 __last1,
129 _InputIter2 __first2, _InputIter2 __last2)
131 while (__first1 != __last1 && __first2 != __last2) {
132 if (*__first1 < *__first2)
134 if (*__first2 < *__first1)
139 if (__first2 == __last2) {
140 return !(__first1 == __last1);
148 __lexicographical_compare_3way(const unsigned char* __first1,
149 const unsigned char* __last1,
150 const unsigned char* __first2,
151 const unsigned char* __last2)
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));
161 __lexicographical_compare_3way(const char* __first1, const char* __last1,
162 const char* __first2, const char* __last2)
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);
171 return __lexicographical_compare_3way((const unsigned char*) __first1,
172 (const unsigned char*) __last1,
173 (const unsigned char*) __first2,
174 (const unsigned char*) __last2);
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.
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
192 template<typename _InputIter1, typename _InputIter2>
194 lexicographical_compare_3way(_InputIter1 __first1, _InputIter1 __last1,
195 _InputIter2 __first2, _InputIter2 __last2)
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>)
205 return __lexicographical_compare_3way(__first1, __last1, __first2, __last2);
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.
211 template<typename _InputIter, typename _Tp, typename _Size>
213 count(_InputIter __first, _InputIter __last,
217 // concept requirements
218 __glibcpp_function_requires(_InputIteratorConcept<_InputIter>)
219 __glibcpp_function_requires(_EqualityComparableConcept<
220 typename iterator_traits<_InputIter>::value_type >)
221 __glibcpp_function_requires(_EqualityComparableConcept<_Tp>)
222 for ( ; __first != __last; ++__first)
223 if (*__first == __value)
227 template<typename _InputIter, typename _Predicate, typename _Size>
229 count_if(_InputIter __first, _InputIter __last,
233 // concept requirements
234 __glibcpp_function_requires(_InputIteratorConcept<_InputIter>)
235 __glibcpp_function_requires(_UnaryPredicateConcept<_Predicate,
236 typename iterator_traits<_InputIter>::value_type>)
237 for ( ; __first != __last; ++__first)
238 if (__pred(*__first))
242 // random_sample and random_sample_n (extensions, not part of the standard).
244 template<typename _ForwardIter, typename _OutputIter, typename _Distance>
246 random_sample_n(_ForwardIter __first, _ForwardIter __last,
247 _OutputIter __out, const _Distance __n)
249 // concept requirements
250 __glibcpp_function_requires(_ForwardIteratorConcept<_ForwardIter>)
251 __glibcpp_function_requires(_OutputIteratorConcept<_OutputIter,
252 typename iterator_traits<_ForwardIter>::value_type>)
254 _Distance __remaining = std::distance(__first, __last);
255 _Distance __m = min(__n, __remaining);
258 if (std::__random_number(__remaining) < __m) {
270 template<typename _ForwardIter, typename _OutputIter, typename _Distance,
271 typename _RandomNumberGenerator>
273 random_sample_n(_ForwardIter __first, _ForwardIter __last,
274 _OutputIter __out, const _Distance __n,
275 _RandomNumberGenerator& __rand)
277 // concept requirements
278 __glibcpp_function_requires(_ForwardIteratorConcept<_ForwardIter>)
279 __glibcpp_function_requires(_OutputIteratorConcept<_OutputIter,
280 typename iterator_traits<_ForwardIter>::value_type>)
281 __glibcpp_function_requires(_UnaryFunctionConcept<
282 _RandomNumberGenerator, _Distance, _Distance>)
284 _Distance __remaining = std::distance(__first, __last);
285 _Distance __m = min(__n, __remaining);
288 if (__rand(__remaining) < __m) {
300 template<typename _InputIter, typename _RandomAccessIter, typename _Distance>
302 __random_sample(_InputIter __first, _InputIter __last,
303 _RandomAccessIter __out,
308 for ( ; __first != __last && __m < __n; ++__m, ++__first)
309 __out[__m] = *__first;
311 while (__first != __last) {
313 _Distance __M = std::__random_number(__t);
315 __out[__M] = *__first;
322 template<typename _InputIter, typename _RandomAccessIter,
323 typename _RandomNumberGenerator, typename _Distance>
325 __random_sample(_InputIter __first, _InputIter __last,
326 _RandomAccessIter __out,
327 _RandomNumberGenerator& __rand,
330 // concept requirements
331 __glibcpp_function_requires(_UnaryFunctionConcept<
332 _RandomNumberGenerator, _Distance, _Distance>)
336 for ( ; __first != __last && __m < __n; ++__m, ++__first)
337 __out[__m] = *__first;
339 while (__first != __last) {
341 _Distance __M = __rand(__t);
343 __out[__M] = *__first;
350 template<typename _InputIter, typename _RandomAccessIter>
351 inline _RandomAccessIter
352 random_sample(_InputIter __first, _InputIter __last,
353 _RandomAccessIter __out_first, _RandomAccessIter __out_last)
355 // concept requirements
356 __glibcpp_function_requires(_InputIteratorConcept<_InputIter>)
357 __glibcpp_function_requires(_Mutable_RandomAccessIteratorConcept<
360 return __random_sample(__first, __last,
361 __out_first, __out_last - __out_first);
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)
371 // concept requirements
372 __glibcpp_function_requires(_InputIteratorConcept<_InputIter>)
373 __glibcpp_function_requires(_Mutable_RandomAccessIteratorConcept<
376 return __random_sample(__first, __last,
378 __out_last - __out_first);
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++
385 template<typename _RandomAccessIter, typename _Distance>
387 __is_heap(_RandomAccessIter __first, _Distance __n)
389 _Distance __parent = 0;
390 for (_Distance __child = 1; __child < __n; ++__child) {
391 if (__first[__parent] < __first[__child])
393 if ((__child & 1) == 0)
399 template<typename _RandomAccessIter, typename _Distance,
400 typename _StrictWeakOrdering>
402 __is_heap(_RandomAccessIter __first, _StrictWeakOrdering __comp,
405 _Distance __parent = 0;
406 for (_Distance __child = 1; __child < __n; ++__child) {
407 if (__comp(__first[__parent], __first[__child]))
409 if ((__child & 1) == 0)
415 template<typename _RandomAccessIter>
417 is_heap(_RandomAccessIter __first, _RandomAccessIter __last)
419 // concept requirements
420 __glibcpp_function_requires(_RandomAccessIteratorConcept<_RandomAccessIter>)
421 __glibcpp_function_requires(_LessThanComparableConcept<
422 typename iterator_traits<_RandomAccessIter>::value_type>)
424 return __is_heap(__first, __last - __first);
427 template<typename _RandomAccessIter, typename _StrictWeakOrdering>
429 is_heap(_RandomAccessIter __first, _RandomAccessIter __last,
430 _StrictWeakOrdering __comp)
432 // concept requirements
433 __glibcpp_function_requires(_RandomAccessIteratorConcept<_RandomAccessIter>)
434 __glibcpp_function_requires(_BinaryPredicateConcept<_StrictWeakOrdering,
435 typename iterator_traits<_RandomAccessIter>::value_type,
436 typename iterator_traits<_RandomAccessIter>::value_type>)
438 return __is_heap(__first, __comp, __last - __first);
441 // is_sorted, a predicated testing whether a range is sorted in
442 // nondescending order. This is an extension, not part of the C++
445 template<typename _ForwardIter>
447 is_sorted(_ForwardIter __first, _ForwardIter __last)
449 // concept requirements
450 __glibcpp_function_requires(_ForwardIteratorConcept<_ForwardIter>)
451 __glibcpp_function_requires(_LessThanComparableConcept<
452 typename iterator_traits<_ForwardIter>::value_type>)
454 if (__first == __last)
457 _ForwardIter __next = __first;
458 for (++__next; __next != __last; __first = __next, ++__next) {
459 if (*__next < *__first)
466 template<typename _ForwardIter, typename _StrictWeakOrdering>
468 is_sorted(_ForwardIter __first, _ForwardIter __last, _StrictWeakOrdering __comp)
470 // concept requirements
471 __glibcpp_function_requires(_ForwardIteratorConcept<_ForwardIter>)
472 __glibcpp_function_requires(_BinaryPredicateConcept<_StrictWeakOrdering,
473 typename iterator_traits<_ForwardIter>::value_type,
474 typename iterator_traits<_ForwardIter>::value_type>)
476 if (__first == __last)
479 _ForwardIter __next = __first;
480 for (++__next; __next != __last; __first = __next, ++__next) {
481 if (__comp(*__next, *__first))
488 } // namespace __gnu_cxx
490 #endif /* _EXT_ALGORITHM */