530 lines
14 KiB
C++
530 lines
14 KiB
C++
// -*- C++ -*-
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// Copyright (C) 2007-2019 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 terms
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// of the GNU General Public License as published by the Free Software
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// Foundation; either version 3, or (at your option) any later
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// version.
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// This library is distributed in the hope that it will be useful, but
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// WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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// 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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* @file parallel/set_operations.h
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* @brief Parallel implementations of set operations for random-access
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* iterators.
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* This file is a GNU parallel extension to the Standard C++ Library.
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*/
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// Written by Marius Elvert and Felix Bondarenko.
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#ifndef _GLIBCXX_PARALLEL_SET_OPERATIONS_H
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#define _GLIBCXX_PARALLEL_SET_OPERATIONS_H 1
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#include <omp.h>
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#include <parallel/settings.h>
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#include <parallel/multiseq_selection.h>
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namespace __gnu_parallel
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{
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template<typename _IIter, typename _OutputIterator>
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_OutputIterator
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__copy_tail(std::pair<_IIter, _IIter> __b,
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std::pair<_IIter, _IIter> __e, _OutputIterator __r)
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{
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if (__b.first != __e.first)
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{
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do
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{
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*__r++ = *__b.first++;
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}
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while (__b.first != __e.first);
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}
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else
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{
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while (__b.second != __e.second)
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*__r++ = *__b.second++;
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}
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return __r;
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}
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template<typename _IIter,
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typename _OutputIterator,
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typename _Compare>
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struct __symmetric_difference_func
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{
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typedef std::iterator_traits<_IIter> _TraitsType;
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typedef typename _TraitsType::difference_type _DifferenceType;
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typedef typename std::pair<_IIter, _IIter> _IteratorPair;
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__symmetric_difference_func(_Compare __comp) : _M_comp(__comp) {}
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_Compare _M_comp;
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_OutputIterator
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_M_invoke(_IIter __a, _IIter __b, _IIter __c, _IIter __d,
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_OutputIterator __r) const
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{
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while (__a != __b && __c != __d)
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{
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if (_M_comp(*__a, *__c))
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{
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*__r = *__a;
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++__a;
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++__r;
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}
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else if (_M_comp(*__c, *__a))
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{
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*__r = *__c;
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++__c;
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++__r;
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}
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else
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{
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++__a;
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++__c;
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}
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}
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return std::copy(__c, __d, std::copy(__a, __b, __r));
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}
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_DifferenceType
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__count(_IIter __a, _IIter __b, _IIter __c, _IIter __d) const
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{
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_DifferenceType __counter = 0;
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while (__a != __b && __c != __d)
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{
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if (_M_comp(*__a, *__c))
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{
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++__a;
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++__counter;
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}
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else if (_M_comp(*__c, *__a))
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{
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++__c;
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++__counter;
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}
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else
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{
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++__a;
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++__c;
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}
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}
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return __counter + (__b - __a) + (__d - __c);
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}
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_OutputIterator
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__first_empty(_IIter __c, _IIter __d, _OutputIterator __out) const
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{ return std::copy(__c, __d, __out); }
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_OutputIterator
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__second_empty(_IIter __a, _IIter __b, _OutputIterator __out) const
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{ return std::copy(__a, __b, __out); }
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};
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template<typename _IIter,
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typename _OutputIterator,
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typename _Compare>
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struct __difference_func
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{
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typedef std::iterator_traits<_IIter> _TraitsType;
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typedef typename _TraitsType::difference_type _DifferenceType;
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typedef typename std::pair<_IIter, _IIter> _IteratorPair;
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__difference_func(_Compare __comp) : _M_comp(__comp) {}
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_Compare _M_comp;
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_OutputIterator
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_M_invoke(_IIter __a, _IIter __b, _IIter __c, _IIter __d,
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_OutputIterator __r) const
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{
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while (__a != __b && __c != __d)
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{
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if (_M_comp(*__a, *__c))
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{
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*__r = *__a;
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++__a;
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++__r;
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}
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else if (_M_comp(*__c, *__a))
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{ ++__c; }
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else
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{
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++__a;
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++__c;
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}
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}
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return std::copy(__a, __b, __r);
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}
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_DifferenceType
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__count(_IIter __a, _IIter __b,
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_IIter __c, _IIter __d) const
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{
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_DifferenceType __counter = 0;
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while (__a != __b && __c != __d)
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{
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if (_M_comp(*__a, *__c))
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{
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++__a;
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++__counter;
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}
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else if (_M_comp(*__c, *__a))
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{ ++__c; }
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else
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{ ++__a; ++__c; }
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}
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return __counter + (__b - __a);
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}
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_OutputIterator
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__first_empty(_IIter, _IIter, _OutputIterator __out) const
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{ return __out; }
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_OutputIterator
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__second_empty(_IIter __a, _IIter __b, _OutputIterator __out) const
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{ return std::copy(__a, __b, __out); }
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};
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template<typename _IIter,
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typename _OutputIterator,
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typename _Compare>
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struct __intersection_func
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{
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typedef std::iterator_traits<_IIter> _TraitsType;
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typedef typename _TraitsType::difference_type _DifferenceType;
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typedef typename std::pair<_IIter, _IIter> _IteratorPair;
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__intersection_func(_Compare __comp) : _M_comp(__comp) {}
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_Compare _M_comp;
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_OutputIterator
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_M_invoke(_IIter __a, _IIter __b, _IIter __c, _IIter __d,
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_OutputIterator __r) const
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{
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while (__a != __b && __c != __d)
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{
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if (_M_comp(*__a, *__c))
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{ ++__a; }
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else if (_M_comp(*__c, *__a))
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{ ++__c; }
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else
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{
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*__r = *__a;
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++__a;
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++__c;
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++__r;
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}
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}
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return __r;
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}
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_DifferenceType
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__count(_IIter __a, _IIter __b, _IIter __c, _IIter __d) const
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{
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_DifferenceType __counter = 0;
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while (__a != __b && __c != __d)
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{
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if (_M_comp(*__a, *__c))
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{ ++__a; }
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else if (_M_comp(*__c, *__a))
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{ ++__c; }
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else
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{
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++__a;
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++__c;
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++__counter;
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}
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}
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return __counter;
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}
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_OutputIterator
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__first_empty(_IIter, _IIter, _OutputIterator __out) const
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{ return __out; }
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_OutputIterator
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__second_empty(_IIter, _IIter, _OutputIterator __out) const
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{ return __out; }
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};
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template<class _IIter, class _OutputIterator, class _Compare>
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struct __union_func
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{
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typedef typename std::iterator_traits<_IIter>::difference_type
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_DifferenceType;
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__union_func(_Compare __comp) : _M_comp(__comp) {}
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_Compare _M_comp;
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_OutputIterator
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_M_invoke(_IIter __a, const _IIter __b, _IIter __c,
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const _IIter __d, _OutputIterator __r) const
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{
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while (__a != __b && __c != __d)
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{
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if (_M_comp(*__a, *__c))
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{
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*__r = *__a;
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++__a;
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}
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else if (_M_comp(*__c, *__a))
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{
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*__r = *__c;
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++__c;
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}
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else
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{
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*__r = *__a;
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++__a;
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++__c;
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}
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++__r;
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}
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return std::copy(__c, __d, std::copy(__a, __b, __r));
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}
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_DifferenceType
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__count(_IIter __a, _IIter __b, _IIter __c, _IIter __d) const
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{
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_DifferenceType __counter = 0;
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while (__a != __b && __c != __d)
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{
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if (_M_comp(*__a, *__c))
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{ ++__a; }
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else if (_M_comp(*__c, *__a))
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{ ++__c; }
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else
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{
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++__a;
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++__c;
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}
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++__counter;
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}
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__counter += (__b - __a);
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__counter += (__d - __c);
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return __counter;
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}
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_OutputIterator
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__first_empty(_IIter __c, _IIter __d, _OutputIterator __out) const
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{ return std::copy(__c, __d, __out); }
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_OutputIterator
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__second_empty(_IIter __a, _IIter __b, _OutputIterator __out) const
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{ return std::copy(__a, __b, __out); }
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};
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template<typename _IIter,
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typename _OutputIterator,
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typename _Operation>
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_OutputIterator
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__parallel_set_operation(_IIter __begin1, _IIter __end1,
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_IIter __begin2, _IIter __end2,
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_OutputIterator __result, _Operation __op)
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{
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_GLIBCXX_CALL((__end1 - __begin1) + (__end2 - __begin2))
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typedef std::iterator_traits<_IIter> _TraitsType;
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typedef typename _TraitsType::difference_type _DifferenceType;
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typedef typename std::pair<_IIter, _IIter> _IteratorPair;
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if (__begin1 == __end1)
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return __op.__first_empty(__begin2, __end2, __result);
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if (__begin2 == __end2)
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return __op.__second_empty(__begin1, __end1, __result);
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const _DifferenceType __size = (__end1 - __begin1) + (__end2 - __begin2);
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const _IteratorPair __sequence[2] = { std::make_pair(__begin1, __end1),
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std::make_pair(__begin2, __end2) };
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_OutputIterator __return_value = __result;
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_DifferenceType *__borders;
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_IteratorPair *__block_begins;
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_DifferenceType* __lengths;
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_ThreadIndex __num_threads =
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std::min<_DifferenceType>(__get_max_threads(),
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std::min(__end1 - __begin1, __end2 - __begin2));
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# pragma omp parallel num_threads(__num_threads)
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{
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# pragma omp single
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{
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__num_threads = omp_get_num_threads();
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__borders = new _DifferenceType[__num_threads + 2];
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__equally_split(__size, __num_threads + 1, __borders);
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__block_begins = new _IteratorPair[__num_threads + 1];
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// Very __start.
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__block_begins[0] = std::make_pair(__begin1, __begin2);
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__lengths = new _DifferenceType[__num_threads];
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} //single
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_ThreadIndex __iam = omp_get_thread_num();
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// _Result from multiseq_partition.
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_IIter __offset[2];
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const _DifferenceType __rank = __borders[__iam + 1];
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multiseq_partition(__sequence, __sequence + 2,
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__rank, __offset, __op._M_comp);
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// allowed to read?
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// together
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// *(__offset[ 0 ] - 1) == *__offset[ 1 ]
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if (__offset[ 0 ] != __begin1 && __offset[1] != __end2
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&& !__op._M_comp(*(__offset[0] - 1), *__offset[1])
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&& !__op._M_comp(*__offset[1], *(__offset[0] - 1)))
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{
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// Avoid split between globally equal elements: move one to
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// front in first sequence.
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--__offset[0];
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}
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_IteratorPair __block_end = __block_begins[__iam + 1] =
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_IteratorPair(__offset[0], __offset[1]);
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// Make sure all threads have their block_begin result written out.
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# pragma omp barrier
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_IteratorPair __block_begin = __block_begins[__iam];
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// Begin working for the first block, while the others except
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// the last start to count.
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if (__iam == 0)
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{
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// The first thread can copy already.
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__lengths[ __iam ] =
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__op._M_invoke(__block_begin.first, __block_end.first,
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__block_begin.second, __block_end.second,
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__result) - __result;
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}
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else
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{
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__lengths[ __iam ] =
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__op.__count(__block_begin.first, __block_end.first,
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__block_begin.second, __block_end.second);
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}
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// Make sure everyone wrote their lengths.
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# pragma omp barrier
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_OutputIterator __r = __result;
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if (__iam == 0)
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{
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// Do the last block.
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for (_ThreadIndex __i = 0; __i < __num_threads; ++__i)
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__r += __lengths[__i];
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__block_begin = __block_begins[__num_threads];
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// Return the result iterator of the last block.
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__return_value =
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__op._M_invoke(__block_begin.first, __end1,
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__block_begin.second, __end2, __r);
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}
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else
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{
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for (_ThreadIndex __i = 0; __i < __iam; ++__i)
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__r += __lengths[ __i ];
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// Reset begins for copy pass.
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__op._M_invoke(__block_begin.first, __block_end.first,
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__block_begin.second, __block_end.second, __r);
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}
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}
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return __return_value;
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}
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template<typename _IIter,
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typename _OutputIterator,
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typename _Compare>
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inline _OutputIterator
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__parallel_set_union(_IIter __begin1, _IIter __end1,
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_IIter __begin2, _IIter __end2,
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_OutputIterator __result, _Compare __comp)
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{
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return __parallel_set_operation(__begin1, __end1, __begin2, __end2,
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__result,
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__union_func< _IIter, _OutputIterator,
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_Compare>(__comp));
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}
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template<typename _IIter,
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typename _OutputIterator,
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typename _Compare>
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inline _OutputIterator
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__parallel_set_intersection(_IIter __begin1, _IIter __end1,
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_IIter __begin2, _IIter __end2,
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_OutputIterator __result, _Compare __comp)
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{
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return __parallel_set_operation(__begin1, __end1, __begin2, __end2,
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__result,
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__intersection_func<_IIter,
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_OutputIterator, _Compare>(__comp));
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}
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template<typename _IIter,
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typename _OutputIterator,
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typename _Compare>
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inline _OutputIterator
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__parallel_set_difference(_IIter __begin1, _IIter __end1,
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_IIter __begin2, _IIter __end2,
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_OutputIterator __result, _Compare __comp)
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{
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return __parallel_set_operation(__begin1, __end1, __begin2, __end2,
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__result,
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__difference_func<_IIter,
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_OutputIterator, _Compare>(__comp));
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}
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template<typename _IIter,
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typename _OutputIterator,
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typename _Compare>
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inline _OutputIterator
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__parallel_set_symmetric_difference(_IIter __begin1, _IIter __end1,
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_IIter __begin2, _IIter __end2,
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_OutputIterator __result,
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_Compare __comp)
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{
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return __parallel_set_operation(__begin1, __end1, __begin2, __end2,
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__result,
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__symmetric_difference_func<_IIter,
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_OutputIterator, _Compare>(__comp));
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}
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}
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#endif /* _GLIBCXX_PARALLEL_SET_OPERATIONS_H */
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