604 lines
19 KiB
C++
604 lines
19 KiB
C++
// Algorithm extensions -*- C++ -*-
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// Copyright (C) 2001-2017 Free Software Foundation, Inc.
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//
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// This file is part of the GNU ISO C++ Library. This library is free
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// software; you can redistribute it and/or modify it under the
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// terms of the GNU General Public License as published by the
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// Free Software Foundation; either version 3, or (at your option)
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// any later version.
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// Under Section 7 of GPL version 3, you are granted additional
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// permissions described in the GCC Runtime Library Exception, version
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// 3.1, as published by the Free Software Foundation.
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// You should have received a copy of the GNU General Public License and
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// a copy of the GCC Runtime Library Exception along with this program;
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// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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// <http://www.gnu.org/licenses/>.
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/*
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*
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* Copyright (c) 1994
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* Hewlett-Packard Company
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*
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* Permission to use, copy, modify, distribute and sell this software
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* and its documentation for any purpose is hereby granted without fee,
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* provided that the above copyright notice appear in all copies and
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* that both that copyright notice and this permission notice appear
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* in supporting documentation. Hewlett-Packard Company makes no
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* representations about the suitability of this software for any
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* purpose. It is provided "as is" without express or implied warranty.
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*
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*
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* Copyright (c) 1996
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* Silicon Graphics Computer Systems, Inc.
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*
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* Permission to use, copy, modify, distribute and sell this software
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* and its documentation for any purpose is hereby granted without fee,
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* provided that the above copyright notice appear in all copies and
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* that both that copyright notice and this permission notice appear
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* in supporting documentation. Silicon Graphics makes no
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* representations about the suitability of this software for any
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* purpose. It is provided "as is" without express or implied warranty.
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*/
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/** @file ext/algorithm
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* This file is a GNU extension to the Standard C++ Library (possibly
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* containing extensions from the HP/SGI STL subset).
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*/
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#ifndef _EXT_ALGORITHM
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#define _EXT_ALGORITHM 1
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#pragma GCC system_header
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#include <algorithm>
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namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
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{
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_GLIBCXX_BEGIN_NAMESPACE_VERSION
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using std::ptrdiff_t;
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using std::min;
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using std::pair;
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using std::input_iterator_tag;
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using std::random_access_iterator_tag;
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using std::iterator_traits;
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//--------------------------------------------------
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// copy_n (not part of the C++ standard)
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template<typename _InputIterator, typename _Size, typename _OutputIterator>
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pair<_InputIterator, _OutputIterator>
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__copy_n(_InputIterator __first, _Size __count,
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_OutputIterator __result,
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input_iterator_tag)
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{
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for ( ; __count > 0; --__count)
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{
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*__result = *__first;
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++__first;
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++__result;
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}
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return pair<_InputIterator, _OutputIterator>(__first, __result);
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}
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template<typename _RAIterator, typename _Size, typename _OutputIterator>
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inline pair<_RAIterator, _OutputIterator>
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__copy_n(_RAIterator __first, _Size __count,
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_OutputIterator __result,
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random_access_iterator_tag)
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{
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_RAIterator __last = __first + __count;
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return pair<_RAIterator, _OutputIterator>(__last, std::copy(__first,
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__last,
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__result));
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}
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/**
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* @brief Copies the range [first,first+count) into [result,result+count).
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* @param __first An input iterator.
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* @param __count The number of elements to copy.
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* @param __result An output iterator.
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* @return A std::pair composed of first+count and result+count.
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*
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* This is an SGI extension.
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* This inline function will boil down to a call to @c memmove whenever
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* possible. Failing that, if random access iterators are passed, then the
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* loop count will be known (and therefore a candidate for compiler
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* optimizations such as unrolling).
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* @ingroup SGIextensions
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*/
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template<typename _InputIterator, typename _Size, typename _OutputIterator>
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inline pair<_InputIterator, _OutputIterator>
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copy_n(_InputIterator __first, _Size __count, _OutputIterator __result)
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{
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// concept requirements
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__glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
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__glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
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typename iterator_traits<_InputIterator>::value_type>)
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return __gnu_cxx::__copy_n(__first, __count, __result,
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std::__iterator_category(__first));
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}
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template<typename _InputIterator1, typename _InputIterator2>
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int
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__lexicographical_compare_3way(_InputIterator1 __first1,
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_InputIterator1 __last1,
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_InputIterator2 __first2,
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_InputIterator2 __last2)
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{
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while (__first1 != __last1 && __first2 != __last2)
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{
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if (*__first1 < *__first2)
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return -1;
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if (*__first2 < *__first1)
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return 1;
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++__first1;
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++__first2;
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}
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if (__first2 == __last2)
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return !(__first1 == __last1);
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else
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return -1;
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}
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inline int
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__lexicographical_compare_3way(const unsigned char* __first1,
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const unsigned char* __last1,
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const unsigned char* __first2,
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const unsigned char* __last2)
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{
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const ptrdiff_t __len1 = __last1 - __first1;
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const ptrdiff_t __len2 = __last2 - __first2;
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const int __result = __builtin_memcmp(__first1, __first2,
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min(__len1, __len2));
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return __result != 0 ? __result
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: (__len1 == __len2 ? 0 : (__len1 < __len2 ? -1 : 1));
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}
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inline int
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__lexicographical_compare_3way(const char* __first1, const char* __last1,
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const char* __first2, const char* __last2)
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{
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#if CHAR_MAX == SCHAR_MAX
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return __lexicographical_compare_3way((const signed char*) __first1,
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(const signed char*) __last1,
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(const signed char*) __first2,
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(const signed char*) __last2);
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#else
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return __lexicographical_compare_3way((const unsigned char*) __first1,
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(const unsigned char*) __last1,
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(const unsigned char*) __first2,
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(const unsigned char*) __last2);
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#endif
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}
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/**
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* @brief @c memcmp on steroids.
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* @param __first1 An input iterator.
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* @param __last1 An input iterator.
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* @param __first2 An input iterator.
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* @param __last2 An input iterator.
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* @return An int, as with @c memcmp.
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*
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* The return value will be less than zero if the first range is
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* <em>lexigraphically less than</em> the second, greater than zero
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* if the second range is <em>lexigraphically less than</em> the
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* first, and zero otherwise.
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* This is an SGI extension.
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* @ingroup SGIextensions
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*/
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template<typename _InputIterator1, typename _InputIterator2>
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int
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lexicographical_compare_3way(_InputIterator1 __first1,
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_InputIterator1 __last1,
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_InputIterator2 __first2,
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_InputIterator2 __last2)
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{
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// concept requirements
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__glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
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__glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
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__glibcxx_function_requires(_LessThanComparableConcept<
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typename iterator_traits<_InputIterator1>::value_type>)
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__glibcxx_function_requires(_LessThanComparableConcept<
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typename iterator_traits<_InputIterator2>::value_type>)
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__glibcxx_requires_valid_range(__first1, __last1);
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__glibcxx_requires_valid_range(__first2, __last2);
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return __lexicographical_compare_3way(__first1, __last1, __first2,
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__last2);
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}
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// count and count_if: this version, whose return type is void, was present
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// in the HP STL, and is retained as an extension for backward compatibility.
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template<typename _InputIterator, typename _Tp, typename _Size>
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void
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count(_InputIterator __first, _InputIterator __last,
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const _Tp& __value,
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_Size& __n)
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{
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// concept requirements
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__glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
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__glibcxx_function_requires(_EqualityComparableConcept<
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typename iterator_traits<_InputIterator>::value_type >)
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__glibcxx_function_requires(_EqualityComparableConcept<_Tp>)
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__glibcxx_requires_valid_range(__first, __last);
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for ( ; __first != __last; ++__first)
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if (*__first == __value)
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++__n;
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}
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template<typename _InputIterator, typename _Predicate, typename _Size>
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void
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count_if(_InputIterator __first, _InputIterator __last,
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_Predicate __pred,
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_Size& __n)
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{
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// concept requirements
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__glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
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__glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,
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typename iterator_traits<_InputIterator>::value_type>)
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__glibcxx_requires_valid_range(__first, __last);
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for ( ; __first != __last; ++__first)
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if (__pred(*__first))
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++__n;
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}
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// random_sample and random_sample_n (extensions, not part of the standard).
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/**
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* This is an SGI extension.
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* @ingroup SGIextensions
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* @doctodo
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*/
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template<typename _ForwardIterator, typename _OutputIterator,
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typename _Distance>
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_OutputIterator
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random_sample_n(_ForwardIterator __first, _ForwardIterator __last,
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_OutputIterator __out, const _Distance __n)
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{
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// concept requirements
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__glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
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__glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
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typename iterator_traits<_ForwardIterator>::value_type>)
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__glibcxx_requires_valid_range(__first, __last);
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_Distance __remaining = std::distance(__first, __last);
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_Distance __m = min(__n, __remaining);
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while (__m > 0)
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{
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if ((std::rand() % __remaining) < __m)
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{
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*__out = *__first;
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++__out;
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--__m;
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}
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--__remaining;
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++__first;
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}
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return __out;
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}
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/**
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* This is an SGI extension.
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* @ingroup SGIextensions
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* @doctodo
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*/
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template<typename _ForwardIterator, typename _OutputIterator,
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typename _Distance, typename _RandomNumberGenerator>
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_OutputIterator
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random_sample_n(_ForwardIterator __first, _ForwardIterator __last,
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_OutputIterator __out, const _Distance __n,
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_RandomNumberGenerator& __rand)
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{
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// concept requirements
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__glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
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__glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
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typename iterator_traits<_ForwardIterator>::value_type>)
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__glibcxx_function_requires(_UnaryFunctionConcept<
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_RandomNumberGenerator, _Distance, _Distance>)
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__glibcxx_requires_valid_range(__first, __last);
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_Distance __remaining = std::distance(__first, __last);
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_Distance __m = min(__n, __remaining);
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while (__m > 0)
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{
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if (__rand(__remaining) < __m)
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{
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*__out = *__first;
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++__out;
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--__m;
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}
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--__remaining;
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++__first;
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}
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return __out;
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}
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template<typename _InputIterator, typename _RandomAccessIterator,
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typename _Distance>
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_RandomAccessIterator
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__random_sample(_InputIterator __first, _InputIterator __last,
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_RandomAccessIterator __out,
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const _Distance __n)
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{
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_Distance __m = 0;
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_Distance __t = __n;
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for ( ; __first != __last && __m < __n; ++__m, ++__first)
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__out[__m] = *__first;
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while (__first != __last)
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{
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++__t;
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_Distance __M = std::rand() % (__t);
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if (__M < __n)
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__out[__M] = *__first;
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++__first;
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}
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return __out + __m;
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}
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template<typename _InputIterator, typename _RandomAccessIterator,
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typename _RandomNumberGenerator, typename _Distance>
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_RandomAccessIterator
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__random_sample(_InputIterator __first, _InputIterator __last,
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_RandomAccessIterator __out,
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_RandomNumberGenerator& __rand,
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const _Distance __n)
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{
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// concept requirements
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__glibcxx_function_requires(_UnaryFunctionConcept<
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_RandomNumberGenerator, _Distance, _Distance>)
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_Distance __m = 0;
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_Distance __t = __n;
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for ( ; __first != __last && __m < __n; ++__m, ++__first)
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__out[__m] = *__first;
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while (__first != __last)
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{
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++__t;
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_Distance __M = __rand(__t);
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if (__M < __n)
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__out[__M] = *__first;
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++__first;
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}
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return __out + __m;
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}
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/**
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* This is an SGI extension.
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* @ingroup SGIextensions
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* @doctodo
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*/
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template<typename _InputIterator, typename _RandomAccessIterator>
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inline _RandomAccessIterator
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random_sample(_InputIterator __first, _InputIterator __last,
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_RandomAccessIterator __out_first,
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_RandomAccessIterator __out_last)
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{
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// concept requirements
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__glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
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__glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
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_RandomAccessIterator>)
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__glibcxx_requires_valid_range(__first, __last);
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__glibcxx_requires_valid_range(__out_first, __out_last);
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return __random_sample(__first, __last,
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__out_first, __out_last - __out_first);
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}
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/**
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* This is an SGI extension.
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* @ingroup SGIextensions
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* @doctodo
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*/
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template<typename _InputIterator, typename _RandomAccessIterator,
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typename _RandomNumberGenerator>
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inline _RandomAccessIterator
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random_sample(_InputIterator __first, _InputIterator __last,
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_RandomAccessIterator __out_first,
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_RandomAccessIterator __out_last,
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_RandomNumberGenerator& __rand)
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{
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// concept requirements
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__glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
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__glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
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_RandomAccessIterator>)
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__glibcxx_requires_valid_range(__first, __last);
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__glibcxx_requires_valid_range(__out_first, __out_last);
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return __random_sample(__first, __last,
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__out_first, __rand,
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__out_last - __out_first);
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}
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#if __cplusplus >= 201103L
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using std::is_heap;
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#else
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/**
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* This is an SGI extension.
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* @ingroup SGIextensions
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* @doctodo
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*/
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template<typename _RandomAccessIterator>
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inline bool
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is_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
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{
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// concept requirements
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__glibcxx_function_requires(_RandomAccessIteratorConcept<
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_RandomAccessIterator>)
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__glibcxx_function_requires(_LessThanComparableConcept<
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typename iterator_traits<_RandomAccessIterator>::value_type>)
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__glibcxx_requires_valid_range(__first, __last);
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return std::__is_heap(__first, __last - __first);
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}
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/**
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* This is an SGI extension.
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* @ingroup SGIextensions
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* @doctodo
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*/
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template<typename _RandomAccessIterator, typename _StrictWeakOrdering>
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inline bool
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is_heap(_RandomAccessIterator __first, _RandomAccessIterator __last,
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_StrictWeakOrdering __comp)
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{
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// concept requirements
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__glibcxx_function_requires(_RandomAccessIteratorConcept<
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_RandomAccessIterator>)
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__glibcxx_function_requires(_BinaryPredicateConcept<_StrictWeakOrdering,
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typename iterator_traits<_RandomAccessIterator>::value_type,
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typename iterator_traits<_RandomAccessIterator>::value_type>)
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__glibcxx_requires_valid_range(__first, __last);
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return std::__is_heap(__first, __comp, __last - __first);
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}
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#endif
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#if __cplusplus >= 201103L
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using std::is_sorted;
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#else
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// is_sorted, a predicated testing whether a range is sorted in
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// nondescending order. This is an extension, not part of the C++
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// standard.
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/**
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* This is an SGI extension.
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* @ingroup SGIextensions
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* @doctodo
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*/
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template<typename _ForwardIterator>
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bool
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is_sorted(_ForwardIterator __first, _ForwardIterator __last)
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{
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// concept requirements
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__glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
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__glibcxx_function_requires(_LessThanComparableConcept<
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typename iterator_traits<_ForwardIterator>::value_type>)
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__glibcxx_requires_valid_range(__first, __last);
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if (__first == __last)
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return true;
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_ForwardIterator __next = __first;
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for (++__next; __next != __last; __first = __next, ++__next)
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if (*__next < *__first)
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return false;
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return true;
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}
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/**
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* This is an SGI extension.
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* @ingroup SGIextensions
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* @doctodo
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*/
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template<typename _ForwardIterator, typename _StrictWeakOrdering>
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bool
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is_sorted(_ForwardIterator __first, _ForwardIterator __last,
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_StrictWeakOrdering __comp)
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{
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// concept requirements
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__glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)
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__glibcxx_function_requires(_BinaryPredicateConcept<_StrictWeakOrdering,
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typename iterator_traits<_ForwardIterator>::value_type,
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typename iterator_traits<_ForwardIterator>::value_type>)
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__glibcxx_requires_valid_range(__first, __last);
|
|
|
|
if (__first == __last)
|
|
return true;
|
|
|
|
_ForwardIterator __next = __first;
|
|
for (++__next; __next != __last; __first = __next, ++__next)
|
|
if (__comp(*__next, *__first))
|
|
return false;
|
|
return true;
|
|
}
|
|
#endif // C++11
|
|
|
|
/**
|
|
* @brief Find the median of three values.
|
|
* @param __a A value.
|
|
* @param __b A value.
|
|
* @param __c A value.
|
|
* @return One of @p a, @p b or @p c.
|
|
*
|
|
* If @c {l,m,n} is some convolution of @p {a,b,c} such that @c l<=m<=n
|
|
* then the value returned will be @c m.
|
|
* This is an SGI extension.
|
|
* @ingroup SGIextensions
|
|
*/
|
|
template<typename _Tp>
|
|
const _Tp&
|
|
__median(const _Tp& __a, const _Tp& __b, const _Tp& __c)
|
|
{
|
|
// concept requirements
|
|
__glibcxx_function_requires(_LessThanComparableConcept<_Tp>)
|
|
if (__a < __b)
|
|
if (__b < __c)
|
|
return __b;
|
|
else if (__a < __c)
|
|
return __c;
|
|
else
|
|
return __a;
|
|
else if (__a < __c)
|
|
return __a;
|
|
else if (__b < __c)
|
|
return __c;
|
|
else
|
|
return __b;
|
|
}
|
|
|
|
/**
|
|
* @brief Find the median of three values using a predicate for comparison.
|
|
* @param __a A value.
|
|
* @param __b A value.
|
|
* @param __c A value.
|
|
* @param __comp A binary predicate.
|
|
* @return One of @p a, @p b or @p c.
|
|
*
|
|
* If @c {l,m,n} is some convolution of @p {a,b,c} such that @p comp(l,m)
|
|
* and @p comp(m,n) are both true then the value returned will be @c m.
|
|
* This is an SGI extension.
|
|
* @ingroup SGIextensions
|
|
*/
|
|
template<typename _Tp, typename _Compare>
|
|
const _Tp&
|
|
__median(const _Tp& __a, const _Tp& __b, const _Tp& __c, _Compare __comp)
|
|
{
|
|
// concept requirements
|
|
__glibcxx_function_requires(_BinaryFunctionConcept<_Compare, bool,
|
|
_Tp, _Tp>)
|
|
if (__comp(__a, __b))
|
|
if (__comp(__b, __c))
|
|
return __b;
|
|
else if (__comp(__a, __c))
|
|
return __c;
|
|
else
|
|
return __a;
|
|
else if (__comp(__a, __c))
|
|
return __a;
|
|
else if (__comp(__b, __c))
|
|
return __c;
|
|
else
|
|
return __b;
|
|
}
|
|
|
|
_GLIBCXX_END_NAMESPACE_VERSION
|
|
} // namespace
|
|
|
|
#endif /* _EXT_ALGORITHM */
|