537 lines
17 KiB
C++
537 lines
17 KiB
C++
// Algorithm extensions -*- C++ -*-
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// Copyright (C) 2001, 2002 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 2, 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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// You should have received a copy of the GNU General Public License along
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// with this library; see the file COPYING. If not, write to the Free
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// Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
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// USA.
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// As a special exception, you may use this file as part of a free software
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// library without restriction. Specifically, if other files instantiate
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// templates or use macros or inline functions from this file, or you compile
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// this file and link it with other files to produce an executable, this
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// file does not by itself cause the resulting executable to be covered by
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// the GNU General Public License. This exception does not however
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// invalidate any other reasons why the executable file might be covered by
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// the GNU General Public License.
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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). You should only
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* include this header if you are using GCC 3 or later.
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*/
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#ifndef _EXT_ALGORITHM
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#define _EXT_ALGORITHM
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#pragma GCC system_header
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#include <algorithm>
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namespace __gnu_cxx
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{
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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 _InputIter, typename _Size, typename _OutputIter>
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pair<_InputIter, _OutputIter>
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__copy_n(_InputIter __first, _Size __count,
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_OutputIter __result,
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input_iterator_tag)
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{
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for ( ; __count > 0; --__count) {
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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<_InputIter, _OutputIter>(__first, __result);
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}
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template<typename _RAIter, typename _Size, typename _OutputIter>
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inline pair<_RAIter, _OutputIter>
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__copy_n(_RAIter __first, _Size __count,
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_OutputIter __result,
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random_access_iterator_tag)
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{
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_RAIter __last = __first + __count;
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return pair<_RAIter, _OutputIter>(__last,
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std::copy(__first, __last, __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 _InputIter, typename _Size, typename _OutputIter>
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inline pair<_InputIter, _OutputIter>
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copy_n(_InputIter __first, _Size __count, _OutputIter __result)
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{
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// concept requirements
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__glibcpp_function_requires(_InputIteratorConcept<_InputIter>)
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__glibcpp_function_requires(_OutputIteratorConcept<_OutputIter,
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typename iterator_traits<_InputIter>::value_type>)
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return __copy_n(__first, __count, __result,
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std::__iterator_category(__first));
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}
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template<typename _InputIter1, typename _InputIter2>
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int
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__lexicographical_compare_3way(_InputIter1 __first1, _InputIter1 __last1,
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_InputIter2 __first2, _InputIter2 __last2)
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{
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while (__first1 != __last1 && __first2 != __last2) {
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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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}
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else {
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return -1;
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}
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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 = std::memcmp(__first1, __first2, 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(
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(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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* "lexigraphically less than" the second, greater than zero if the second
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* range is "lexigraphically less than" the 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 _InputIter1, typename _InputIter2>
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int
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lexicographical_compare_3way(_InputIter1 __first1, _InputIter1 __last1,
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_InputIter2 __first2, _InputIter2 __last2)
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{
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// concept requirements
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__glibcpp_function_requires(_InputIteratorConcept<_InputIter1>)
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__glibcpp_function_requires(_InputIteratorConcept<_InputIter2>)
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__glibcpp_function_requires(_LessThanComparableConcept<
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typename iterator_traits<_InputIter1>::value_type>)
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__glibcpp_function_requires(_LessThanComparableConcept<
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typename iterator_traits<_InputIter2>::value_type>)
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return __lexicographical_compare_3way(__first1, __last1, __first2, __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 _InputIter, typename _Tp, typename _Size>
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void
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count(_InputIter __first, _InputIter __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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__glibcpp_function_requires(_InputIteratorConcept<_InputIter>)
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__glibcpp_function_requires(_EqualityComparableConcept<
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typename iterator_traits<_InputIter>::value_type >)
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__glibcpp_function_requires(_EqualityComparableConcept<_Tp>)
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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 _InputIter, typename _Predicate, typename _Size>
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void
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count_if(_InputIter __first, _InputIter __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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__glibcpp_function_requires(_InputIteratorConcept<_InputIter>)
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__glibcpp_function_requires(_UnaryPredicateConcept<_Predicate,
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typename iterator_traits<_InputIter>::value_type>)
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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 _ForwardIter, typename _OutputIter, typename _Distance>
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_OutputIter
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random_sample_n(_ForwardIter __first, _ForwardIter __last,
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_OutputIter __out, const _Distance __n)
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{
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// concept requirements
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__glibcpp_function_requires(_ForwardIteratorConcept<_ForwardIter>)
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__glibcpp_function_requires(_OutputIteratorConcept<_OutputIter,
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typename iterator_traits<_ForwardIter>::value_type>)
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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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if (std::__random_number(__remaining) < __m) {
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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 _ForwardIter, typename _OutputIter, typename _Distance,
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typename _RandomNumberGenerator>
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_OutputIter
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random_sample_n(_ForwardIter __first, _ForwardIter __last,
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_OutputIter __out, const _Distance __n,
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_RandomNumberGenerator& __rand)
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{
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// concept requirements
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__glibcpp_function_requires(_ForwardIteratorConcept<_ForwardIter>)
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__glibcpp_function_requires(_OutputIteratorConcept<_OutputIter,
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typename iterator_traits<_ForwardIter>::value_type>)
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__glibcpp_function_requires(_UnaryFunctionConcept<
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_RandomNumberGenerator, _Distance, _Distance>)
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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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if (__rand(__remaining) < __m) {
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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 _InputIter, typename _RandomAccessIter, typename _Distance>
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_RandomAccessIter
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__random_sample(_InputIter __first, _InputIter __last,
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_RandomAccessIter __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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++__t;
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_Distance __M = std::__random_number(__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 _InputIter, typename _RandomAccessIter,
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typename _RandomNumberGenerator, typename _Distance>
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_RandomAccessIter
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__random_sample(_InputIter __first, _InputIter __last,
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_RandomAccessIter __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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__glibcpp_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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++__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 _InputIter, typename _RandomAccessIter>
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inline _RandomAccessIter
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random_sample(_InputIter __first, _InputIter __last,
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_RandomAccessIter __out_first, _RandomAccessIter __out_last)
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{
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// concept requirements
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__glibcpp_function_requires(_InputIteratorConcept<_InputIter>)
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__glibcpp_function_requires(_Mutable_RandomAccessIteratorConcept<
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_RandomAccessIter>)
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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 _InputIter, typename _RandomAccessIter,
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typename _RandomNumberGenerator>
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inline _RandomAccessIter
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random_sample(_InputIter __first, _InputIter __last,
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_RandomAccessIter __out_first, _RandomAccessIter __out_last,
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_RandomNumberGenerator& __rand)
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{
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// concept requirements
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__glibcpp_function_requires(_InputIteratorConcept<_InputIter>)
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__glibcpp_function_requires(_Mutable_RandomAccessIteratorConcept<
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_RandomAccessIter>)
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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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// is_heap, a predicate testing whether or not a range is
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// a heap. This function is an extension, not part of the C++
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// standard.
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template<typename _RandomAccessIter, typename _Distance>
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bool
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__is_heap(_RandomAccessIter __first, _Distance __n)
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{
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_Distance __parent = 0;
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for (_Distance __child = 1; __child < __n; ++__child) {
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if (__first[__parent] < __first[__child])
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return false;
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if ((__child & 1) == 0)
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++__parent;
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}
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return true;
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}
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template<typename _RandomAccessIter, typename _Distance,
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typename _StrictWeakOrdering>
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bool
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__is_heap(_RandomAccessIter __first, _StrictWeakOrdering __comp,
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_Distance __n)
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{
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_Distance __parent = 0;
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for (_Distance __child = 1; __child < __n; ++__child) {
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if (__comp(__first[__parent], __first[__child]))
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return false;
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if ((__child & 1) == 0)
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++__parent;
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}
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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 _RandomAccessIter>
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inline bool
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is_heap(_RandomAccessIter __first, _RandomAccessIter __last)
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{
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// concept requirements
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__glibcpp_function_requires(_RandomAccessIteratorConcept<_RandomAccessIter>)
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__glibcpp_function_requires(_LessThanComparableConcept<
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typename iterator_traits<_RandomAccessIter>::value_type>)
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return __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 _RandomAccessIter, typename _StrictWeakOrdering>
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inline bool
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is_heap(_RandomAccessIter __first, _RandomAccessIter __last,
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_StrictWeakOrdering __comp)
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{
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// concept requirements
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__glibcpp_function_requires(_RandomAccessIteratorConcept<_RandomAccessIter>)
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__glibcpp_function_requires(_BinaryPredicateConcept<_StrictWeakOrdering,
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typename iterator_traits<_RandomAccessIter>::value_type,
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typename iterator_traits<_RandomAccessIter>::value_type>)
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return __is_heap(__first, __comp, __last - __first);
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}
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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 _ForwardIter>
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bool
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is_sorted(_ForwardIter __first, _ForwardIter __last)
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{
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// concept requirements
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__glibcpp_function_requires(_ForwardIteratorConcept<_ForwardIter>)
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__glibcpp_function_requires(_LessThanComparableConcept<
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typename iterator_traits<_ForwardIter>::value_type>)
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if (__first == __last)
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return true;
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_ForwardIter __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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}
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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 _ForwardIter, typename _StrictWeakOrdering>
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bool
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is_sorted(_ForwardIter __first, _ForwardIter __last, _StrictWeakOrdering __comp)
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{
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// concept requirements
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__glibcpp_function_requires(_ForwardIteratorConcept<_ForwardIter>)
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__glibcpp_function_requires(_BinaryPredicateConcept<_StrictWeakOrdering,
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typename iterator_traits<_ForwardIter>::value_type,
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typename iterator_traits<_ForwardIter>::value_type>)
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if (__first == __last)
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return true;
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_ForwardIter __next = __first;
|
|
for (++__next; __next != __last; __first = __next, ++__next) {
|
|
if (__comp(*__next, *__first))
|
|
return false;
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
} // namespace __gnu_cxx
|
|
|
|
#endif /* _EXT_ALGORITHM */
|