// Algorithm extensions -*- C++ -*- // Copyright (C) 2001-2020 Free Software Foundation, Inc. // // This file is part of the GNU ISO C++ Library. This library is free // software; you can redistribute it and/or modify it under the // terms of the GNU General Public License as published by the // Free Software Foundation; either version 3, or (at your option) // any later version. // This library is distributed in the hope that it will be useful, // but WITHOUT ANY WARRANTY; without even the implied warranty of // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the // GNU General Public License for more details. // Under Section 7 of GPL version 3, you are granted additional // permissions described in the GCC Runtime Library Exception, version // 3.1, as published by the Free Software Foundation. // You should have received a copy of the GNU General Public License and // a copy of the GCC Runtime Library Exception along with this program; // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see // <http://www.gnu.org/licenses/>. /* * * Copyright (c) 1994 * Hewlett-Packard Company * * Permission to use, copy, modify, distribute and sell this software * and its documentation for any purpose is hereby granted without fee, * provided that the above copyright notice appear in all copies and * that both that copyright notice and this permission notice appear * in supporting documentation. Hewlett-Packard Company makes no * representations about the suitability of this software for any * purpose. It is provided "as is" without express or implied warranty. * * * Copyright (c) 1996 * Silicon Graphics Computer Systems, Inc. * * Permission to use, copy, modify, distribute and sell this software * and its documentation for any purpose is hereby granted without fee, * provided that the above copyright notice appear in all copies and * that both that copyright notice and this permission notice appear * in supporting documentation. Silicon Graphics makes no * representations about the suitability of this software for any * purpose. It is provided "as is" without express or implied warranty. */ /** @file ext/algorithm * This file is a GNU extension to the Standard C++ Library (possibly * containing extensions from the HP/SGI STL subset). */ #ifndef _EXT_ALGORITHM #define _EXT_ALGORITHM 1 #pragma GCC system_header #include <algorithm> namespace __gnu_cxx _GLIBCXX_VISIBILITY(default) { _GLIBCXX_BEGIN_NAMESPACE_VERSION //-------------------------------------------------- // copy_n (not part of the C++ standard) template<typename _InputIterator, typename _Size, typename _OutputIterator> std::pair<_InputIterator, _OutputIterator> __copy_n(_InputIterator __first, _Size __count, _OutputIterator __result, std::input_iterator_tag) { for ( ; __count > 0; --__count) { *__result = *__first; ++__first; ++__result; } return std::pair<_InputIterator, _OutputIterator>(__first, __result); } template<typename _RAIterator, typename _Size, typename _OutputIterator> inline std::pair<_RAIterator, _OutputIterator> __copy_n(_RAIterator __first, _Size __count, _OutputIterator __result, std::random_access_iterator_tag) { _RAIterator __last = __first + __count; return std::pair<_RAIterator, _OutputIterator>(__last, std::copy(__first, __last, __result)); } /** * @brief Copies the range [first,first+count) into [result,result+count). * @param __first An input iterator. * @param __count The number of elements to copy. * @param __result An output iterator. * @return A std::pair composed of first+count and result+count. * * This is an SGI extension. * This inline function will boil down to a call to @c memmove whenever * possible. Failing that, if random access iterators are passed, then the * loop count will be known (and therefore a candidate for compiler * optimizations such as unrolling). * @ingroup SGIextensions */ template<typename _InputIterator, typename _Size, typename _OutputIterator> inline std::pair<_InputIterator, _OutputIterator> copy_n(_InputIterator __first, _Size __count, _OutputIterator __result) { // concept requirements __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>) __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator, typename std::iterator_traits<_InputIterator>::value_type>) return __gnu_cxx::__copy_n(__first, __count, __result, std::__iterator_category(__first)); } template<typename _InputIterator1, typename _InputIterator2> int __lexicographical_compare_3way(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2) { while (__first1 != __last1 && __first2 != __last2) { if (*__first1 < *__first2) return -1; if (*__first2 < *__first1) return 1; ++__first1; ++__first2; } if (__first2 == __last2) return !(__first1 == __last1); else return -1; } inline int __lexicographical_compare_3way(const unsigned char* __first1, const unsigned char* __last1, const unsigned char* __first2, const unsigned char* __last2) { const std::ptrdiff_t __len1 = __last1 - __first1; const std::ptrdiff_t __len2 = __last2 - __first2; const int __result = __builtin_memcmp(__first1, __first2, (std::min)(__len1, __len2)); return __result != 0 ? __result : (__len1 == __len2 ? 0 : (__len1 < __len2 ? -1 : 1)); } inline int __lexicographical_compare_3way(const char* __first1, const char* __last1, const char* __first2, const char* __last2) { #if CHAR_MAX == SCHAR_MAX return __lexicographical_compare_3way((const signed char*) __first1, (const signed char*) __last1, (const signed char*) __first2, (const signed char*) __last2); #else return __lexicographical_compare_3way((const unsigned char*) __first1, (const unsigned char*) __last1, (const unsigned char*) __first2, (const unsigned char*) __last2); #endif } /** * @brief @c memcmp on steroids. * @param __first1 An input iterator. * @param __last1 An input iterator. * @param __first2 An input iterator. * @param __last2 An input iterator. * @return An int, as with @c memcmp. * * The return value will be less than zero if the first range is * <em>lexigraphically less than</em> the second, greater than zero * if the second range is <em>lexigraphically less than</em> the * first, and zero otherwise. * This is an SGI extension. * @ingroup SGIextensions */ template<typename _InputIterator1, typename _InputIterator2> int lexicographical_compare_3way(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2) { // concept requirements __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>) __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>) __glibcxx_function_requires(_LessThanComparableConcept< typename std::iterator_traits<_InputIterator1>::value_type>) __glibcxx_function_requires(_LessThanComparableConcept< typename std::iterator_traits<_InputIterator2>::value_type>) __glibcxx_requires_valid_range(__first1, __last1); __glibcxx_requires_valid_range(__first2, __last2); return __lexicographical_compare_3way(__first1, __last1, __first2, __last2); } // count and count_if: this version, whose return type is void, was present // in the HP STL, and is retained as an extension for backward compatibility. template<typename _InputIterator, typename _Tp, typename _Size> void count(_InputIterator __first, _InputIterator __last, const _Tp& __value, _Size& __n) { // concept requirements __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>) __glibcxx_function_requires(_EqualityComparableConcept< typename std::iterator_traits<_InputIterator>::value_type >) __glibcxx_function_requires(_EqualityComparableConcept<_Tp>) __glibcxx_requires_valid_range(__first, __last); for ( ; __first != __last; ++__first) if (*__first == __value) ++__n; } template<typename _InputIterator, typename _Predicate, typename _Size> void count_if(_InputIterator __first, _InputIterator __last, _Predicate __pred, _Size& __n) { // concept requirements __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>) __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate, typename std::iterator_traits<_InputIterator>::value_type>) __glibcxx_requires_valid_range(__first, __last); for ( ; __first != __last; ++__first) if (__pred(*__first)) ++__n; } // random_sample and random_sample_n (extensions, not part of the standard). /** * This is an SGI extension. * @ingroup SGIextensions * @doctodo */ template<typename _ForwardIterator, typename _OutputIterator, typename _Distance> _OutputIterator random_sample_n(_ForwardIterator __first, _ForwardIterator __last, _OutputIterator __out, const _Distance __n) { // concept requirements __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>) __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator, typename std::iterator_traits<_ForwardIterator>::value_type>) __glibcxx_requires_valid_range(__first, __last); _Distance __remaining = std::distance(__first, __last); _Distance __m = (std::min)(__n, __remaining); while (__m > 0) { if ((std::rand() % __remaining) < __m) { *__out = *__first; ++__out; --__m; } --__remaining; ++__first; } return __out; } /** * This is an SGI extension. * @ingroup SGIextensions * @doctodo */ template<typename _ForwardIterator, typename _OutputIterator, typename _Distance, typename _RandomNumberGenerator> _OutputIterator random_sample_n(_ForwardIterator __first, _ForwardIterator __last, _OutputIterator __out, const _Distance __n, _RandomNumberGenerator& __rand) { // concept requirements __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>) __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator, typename std::iterator_traits<_ForwardIterator>::value_type>) __glibcxx_function_requires(_UnaryFunctionConcept< _RandomNumberGenerator, _Distance, _Distance>) __glibcxx_requires_valid_range(__first, __last); _Distance __remaining = std::distance(__first, __last); _Distance __m = (std::min)(__n, __remaining); while (__m > 0) { if (__rand(__remaining) < __m) { *__out = *__first; ++__out; --__m; } --__remaining; ++__first; } return __out; } template<typename _InputIterator, typename _RandomAccessIterator, typename _Distance> _RandomAccessIterator __random_sample(_InputIterator __first, _InputIterator __last, _RandomAccessIterator __out, const _Distance __n) { _Distance __m = 0; _Distance __t = __n; for ( ; __first != __last && __m < __n; ++__m, ++__first) __out[__m] = *__first; while (__first != __last) { ++__t; _Distance __M = std::rand() % (__t); if (__M < __n) __out[__M] = *__first; ++__first; } return __out + __m; } template<typename _InputIterator, typename _RandomAccessIterator, typename _RandomNumberGenerator, typename _Distance> _RandomAccessIterator __random_sample(_InputIterator __first, _InputIterator __last, _RandomAccessIterator __out, _RandomNumberGenerator& __rand, const _Distance __n) { // concept requirements __glibcxx_function_requires(_UnaryFunctionConcept< _RandomNumberGenerator, _Distance, _Distance>) _Distance __m = 0; _Distance __t = __n; for ( ; __first != __last && __m < __n; ++__m, ++__first) __out[__m] = *__first; while (__first != __last) { ++__t; _Distance __M = __rand(__t); if (__M < __n) __out[__M] = *__first; ++__first; } return __out + __m; } /** * This is an SGI extension. * @ingroup SGIextensions * @doctodo */ template<typename _InputIterator, typename _RandomAccessIterator> inline _RandomAccessIterator random_sample(_InputIterator __first, _InputIterator __last, _RandomAccessIterator __out_first, _RandomAccessIterator __out_last) { // concept requirements __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>) __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept< _RandomAccessIterator>) __glibcxx_requires_valid_range(__first, __last); __glibcxx_requires_valid_range(__out_first, __out_last); return __random_sample(__first, __last, __out_first, __out_last - __out_first); } /** * This is an SGI extension. * @ingroup SGIextensions * @doctodo */ template<typename _InputIterator, typename _RandomAccessIterator, typename _RandomNumberGenerator> inline _RandomAccessIterator random_sample(_InputIterator __first, _InputIterator __last, _RandomAccessIterator __out_first, _RandomAccessIterator __out_last, _RandomNumberGenerator& __rand) { // concept requirements __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>) __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept< _RandomAccessIterator>) __glibcxx_requires_valid_range(__first, __last); __glibcxx_requires_valid_range(__out_first, __out_last); return __random_sample(__first, __last, __out_first, __rand, __out_last - __out_first); } #if __cplusplus >= 201103L using std::is_heap; #else /** * This is an SGI extension. * @ingroup SGIextensions * @doctodo */ template<typename _RandomAccessIterator> inline bool is_heap(_RandomAccessIterator __first, _RandomAccessIterator __last) { // concept requirements __glibcxx_function_requires(_RandomAccessIteratorConcept< _RandomAccessIterator>) __glibcxx_function_requires(_LessThanComparableConcept< typename std::iterator_traits<_RandomAccessIterator>::value_type>) __glibcxx_requires_valid_range(__first, __last); return std::__is_heap(__first, __last - __first); } /** * This is an SGI extension. * @ingroup SGIextensions * @doctodo */ template<typename _RandomAccessIterator, typename _StrictWeakOrdering> inline bool is_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _StrictWeakOrdering __comp) { // concept requirements __glibcxx_function_requires(_RandomAccessIteratorConcept< _RandomAccessIterator>) __glibcxx_function_requires(_BinaryPredicateConcept<_StrictWeakOrdering, typename std::iterator_traits<_RandomAccessIterator>::value_type, typename std::iterator_traits<_RandomAccessIterator>::value_type>) __glibcxx_requires_valid_range(__first, __last); return std::__is_heap(__first, __comp, __last - __first); } #endif #if __cplusplus >= 201103L using std::is_sorted; #else // is_sorted, a predicated testing whether a range is sorted in // nondescending order. This is an extension, not part of the C++ // standard. /** * This is an SGI extension. * @ingroup SGIextensions * @doctodo */ template<typename _ForwardIterator> bool is_sorted(_ForwardIterator __first, _ForwardIterator __last) { // concept requirements __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>) __glibcxx_function_requires(_LessThanComparableConcept< typename std::iterator_traits<_ForwardIterator>::value_type>) __glibcxx_requires_valid_range(__first, __last); if (__first == __last) return true; _ForwardIterator __next = __first; for (++__next; __next != __last; __first = __next, ++__next) if (*__next < *__first) return false; return true; } /** * This is an SGI extension. * @ingroup SGIextensions * @doctodo */ template<typename _ForwardIterator, typename _StrictWeakOrdering> bool is_sorted(_ForwardIterator __first, _ForwardIterator __last, _StrictWeakOrdering __comp) { // concept requirements __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>) __glibcxx_function_requires(_BinaryPredicateConcept<_StrictWeakOrdering, typename std::iterator_traits<_ForwardIterator>::value_type, typename std::iterator_traits<_ForwardIterator>::value_type>) __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 */