| // 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 */ |