2065 lines
68 KiB
C++
2065 lines
68 KiB
C++
// -*- C++ -*-
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// Copyright (C) 2007, 2008, 2009, 2010 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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/** @file parallel/multiway_merge.h
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* @brief Implementation of sequential and parallel multiway merge.
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*
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* Explanations on the high-speed merging routines in the appendix of
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*
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* P. Sanders.
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* Fast priority queues for cached memory.
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* ACM Journal of Experimental Algorithmics, 5, 2000.
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*
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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 Johannes Singler and Manuel Holtgrewe.
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#ifndef _GLIBCXX_PARALLEL_MULTIWAY_MERGE_H
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#define _GLIBCXX_PARALLEL_MULTIWAY_MERGE_H
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#include <vector>
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#include <bits/stl_algo.h>
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#include <parallel/features.h>
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#include <parallel/parallel.h>
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#include <parallel/losertree.h>
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#if _GLIBCXX_ASSERTIONS
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#include <parallel/checkers.h>
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#endif
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/** @brief Length of a sequence described by a pair of iterators. */
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#define _GLIBCXX_PARALLEL_LENGTH(__s) ((__s).second - (__s).first)
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namespace __gnu_parallel
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{
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/** @brief _Iterator wrapper supporting an implicit supremum at the end
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* of the sequence, dominating all comparisons.
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*
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* The implicit supremum comes with a performance cost.
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*
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* Deriving from _RAIter is not possible since
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* _RAIter need not be a class.
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*/
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template<typename _RAIter, typename _Compare>
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class _GuardedIterator
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{
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private:
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/** @brief Current iterator __position. */
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_RAIter _M_current;
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/** @brief End iterator of the sequence. */
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_RAIter _M_end;
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/** @brief _Compare. */
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_Compare& __comp;
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public:
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/** @brief Constructor. Sets iterator to beginning of sequence.
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* @param __begin Begin iterator of sequence.
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* @param __end End iterator of sequence.
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* @param __comp Comparator provided for associated overloaded
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* compare operators. */
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_GuardedIterator(_RAIter __begin, _RAIter __end, _Compare& __comp)
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: _M_current(__begin), _M_end(__end), __comp(__comp)
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{ }
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/** @brief Pre-increment operator.
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* @return This. */
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_GuardedIterator<_RAIter, _Compare>&
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operator++()
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{
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++_M_current;
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return *this;
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}
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/** @brief Dereference operator.
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* @return Referenced element. */
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typename std::iterator_traits<_RAIter>::value_type&
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operator*()
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{ return *_M_current; }
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/** @brief Convert to wrapped iterator.
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* @return Wrapped iterator. */
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operator _RAIter()
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{ return _M_current; }
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/** @brief Compare two elements referenced by guarded iterators.
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* @param __bi1 First iterator.
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* @param __bi2 Second iterator.
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* @return @c true if less. */
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friend bool
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operator<(_GuardedIterator<_RAIter, _Compare>& __bi1,
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_GuardedIterator<_RAIter, _Compare>& __bi2)
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{
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if (__bi1._M_current == __bi1._M_end) // __bi1 is sup
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return __bi2._M_current == __bi2._M_end; // __bi2 is not sup
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if (__bi2._M_current == __bi2._M_end) // __bi2 is sup
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return true;
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return (__bi1.__comp)(*__bi1, *__bi2); // normal compare
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}
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/** @brief Compare two elements referenced by guarded iterators.
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* @param __bi1 First iterator.
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* @param __bi2 Second iterator.
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* @return @c True if less equal. */
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friend bool
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operator<=(_GuardedIterator<_RAIter, _Compare>& __bi1,
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_GuardedIterator<_RAIter, _Compare>& __bi2)
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{
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if (__bi2._M_current == __bi2._M_end) // __bi1 is sup
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return __bi1._M_current != __bi1._M_end; // __bi2 is not sup
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if (__bi1._M_current == __bi1._M_end) // __bi2 is sup
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return false;
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return !(__bi1.__comp)(*__bi2, *__bi1); // normal compare
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}
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};
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template<typename _RAIter, typename _Compare>
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class _UnguardedIterator
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{
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private:
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/** @brief Current iterator __position. */
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_RAIter _M_current;
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/** @brief _Compare. */
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mutable _Compare& __comp;
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public:
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/** @brief Constructor. Sets iterator to beginning of sequence.
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* @param __begin Begin iterator of sequence.
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* @param __end Unused, only for compatibility.
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* @param __comp Unused, only for compatibility. */
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_UnguardedIterator(_RAIter __begin,
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_RAIter /* __end */, _Compare& __comp)
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: _M_current(__begin), __comp(__comp)
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{ }
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/** @brief Pre-increment operator.
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* @return This. */
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_UnguardedIterator<_RAIter, _Compare>&
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operator++()
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{
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++_M_current;
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return *this;
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}
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/** @brief Dereference operator.
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* @return Referenced element. */
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typename std::iterator_traits<_RAIter>::value_type&
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operator*()
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{ return *_M_current; }
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/** @brief Convert to wrapped iterator.
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* @return Wrapped iterator. */
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operator _RAIter()
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{ return _M_current; }
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/** @brief Compare two elements referenced by unguarded iterators.
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* @param __bi1 First iterator.
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* @param __bi2 Second iterator.
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* @return @c true if less. */
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friend bool
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operator<(_UnguardedIterator<_RAIter, _Compare>& __bi1,
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_UnguardedIterator<_RAIter, _Compare>& __bi2)
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{
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// Normal compare.
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return (__bi1.__comp)(*__bi1, *__bi2);
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}
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/** @brief Compare two elements referenced by unguarded iterators.
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* @param __bi1 First iterator.
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* @param __bi2 Second iterator.
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* @return @c True if less equal. */
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friend bool
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operator<=(_UnguardedIterator<_RAIter, _Compare>& __bi1,
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_UnguardedIterator<_RAIter, _Compare>& __bi2)
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{
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// Normal compare.
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return !(__bi1.__comp)(*__bi2, *__bi1);
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}
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};
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/** @brief Highly efficient 3-way merging procedure.
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*
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* Merging is done with the algorithm implementation described by Peter
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* Sanders. Basically, the idea is to minimize the number of necessary
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* comparison after merging an element. The implementation trick
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* that makes this fast is that the order of the sequences is stored
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* in the instruction pointer (translated into labels in C++).
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*
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* This works well for merging up to 4 sequences.
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*
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* Note that making the merging stable does @a not come at a
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* performance hit.
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*
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* Whether the merging is done guarded or unguarded is selected by the
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* used iterator class.
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*
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* @param __seqs_begin Begin iterator of iterator pair input sequence.
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* @param __seqs_end End iterator of iterator pair input sequence.
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* @param __target Begin iterator of output sequence.
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* @param __comp Comparator.
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* @param __length Maximum length to merge, less equal than the
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* total number of elements available.
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*
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* @return End iterator of output sequence.
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*/
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template<template<typename RAI, typename C> class iterator,
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typename _RAIterIterator,
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typename _RAIter3,
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typename _DifferenceTp,
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typename _Compare>
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_RAIter3
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multiway_merge_3_variant(_RAIterIterator __seqs_begin,
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_RAIterIterator __seqs_end,
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_RAIter3 __target,
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_DifferenceTp __length, _Compare __comp)
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{
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_GLIBCXX_CALL(__length);
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typedef _DifferenceTp _DifferenceType;
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typedef typename std::iterator_traits<_RAIterIterator>
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::value_type::first_type
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_RAIter1;
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typedef typename std::iterator_traits<_RAIter1>::value_type
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_ValueType;
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if (__length == 0)
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return __target;
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#if _GLIBCXX_ASSERTIONS
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_DifferenceTp __orig_length = __length;
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#endif
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iterator<_RAIter1, _Compare>
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__seq0(__seqs_begin[0].first, __seqs_begin[0].second, __comp),
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__seq1(__seqs_begin[1].first, __seqs_begin[1].second, __comp),
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__seq2(__seqs_begin[2].first, __seqs_begin[2].second, __comp);
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if (__seq0 <= __seq1)
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{
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if (__seq1 <= __seq2)
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goto __s012;
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else
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if (__seq2 < __seq0)
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goto __s201;
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else
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goto __s021;
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}
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else
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{
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if (__seq1 <= __seq2)
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{
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if (__seq0 <= __seq2)
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goto __s102;
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else
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goto __s120;
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}
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else
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goto __s210;
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}
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#define _GLIBCXX_PARALLEL_MERGE_3_CASE(__a, __b, __c, __c0, __c1) \
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__s ## __a ## __b ## __c : \
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*__target = *__seq ## __a; \
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++__target; \
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--__length; \
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++__seq ## __a; \
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if (__length == 0) goto __finish; \
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if (__seq ## __a __c0 __seq ## __b) goto __s ## __a ## __b ## __c; \
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if (__seq ## __a __c1 __seq ## __c) goto __s ## __b ## __a ## __c; \
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goto __s ## __b ## __c ## __a;
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_GLIBCXX_PARALLEL_MERGE_3_CASE(0, 1, 2, <=, <=);
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_GLIBCXX_PARALLEL_MERGE_3_CASE(1, 2, 0, <=, < );
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_GLIBCXX_PARALLEL_MERGE_3_CASE(2, 0, 1, < , < );
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_GLIBCXX_PARALLEL_MERGE_3_CASE(1, 0, 2, < , <=);
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_GLIBCXX_PARALLEL_MERGE_3_CASE(0, 2, 1, <=, <=);
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_GLIBCXX_PARALLEL_MERGE_3_CASE(2, 1, 0, < , < );
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#undef _GLIBCXX_PARALLEL_MERGE_3_CASE
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__finish:
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;
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#if _GLIBCXX_ASSERTIONS
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_GLIBCXX_PARALLEL_ASSERT(
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((_RAIter1)__seq0 - __seqs_begin[0].first) +
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((_RAIter1)__seq1 - __seqs_begin[1].first) +
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((_RAIter1)__seq2 - __seqs_begin[2].first)
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== __orig_length);
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#endif
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__seqs_begin[0].first = __seq0;
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__seqs_begin[1].first = __seq1;
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__seqs_begin[2].first = __seq2;
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return __target;
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}
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/**
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* @brief Highly efficient 4-way merging procedure.
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*
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* Merging is done with the algorithm implementation described by Peter
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* Sanders. Basically, the idea is to minimize the number of necessary
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* comparison after merging an element. The implementation trick
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|
* that makes this fast is that the order of the sequences is stored
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* in the instruction pointer (translated into goto labels in C++).
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*
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* This works well for merging up to 4 sequences.
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*
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* Note that making the merging stable does @a not come at a
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* performance hit.
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|
*
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* Whether the merging is done guarded or unguarded is selected by the
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* used iterator class.
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*
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* @param __seqs_begin Begin iterator of iterator pair input sequence.
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* @param __seqs_end End iterator of iterator pair input sequence.
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* @param __target Begin iterator of output sequence.
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* @param __comp Comparator.
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* @param __length Maximum length to merge, less equal than the
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* total number of elements available.
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*
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* @return End iterator of output sequence.
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*/
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template<template<typename RAI, typename C> class iterator,
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typename _RAIterIterator,
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typename _RAIter3,
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typename _DifferenceTp,
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typename _Compare>
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_RAIter3
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multiway_merge_4_variant(_RAIterIterator __seqs_begin,
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_RAIterIterator __seqs_end,
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_RAIter3 __target,
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_DifferenceTp __length, _Compare __comp)
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{
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_GLIBCXX_CALL(__length);
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typedef _DifferenceTp _DifferenceType;
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typedef typename std::iterator_traits<_RAIterIterator>
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::value_type::first_type
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_RAIter1;
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typedef typename std::iterator_traits<_RAIter1>::value_type
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_ValueType;
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iterator<_RAIter1, _Compare>
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__seq0(__seqs_begin[0].first, __seqs_begin[0].second, __comp),
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__seq1(__seqs_begin[1].first, __seqs_begin[1].second, __comp),
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__seq2(__seqs_begin[2].first, __seqs_begin[2].second, __comp),
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__seq3(__seqs_begin[3].first, __seqs_begin[3].second, __comp);
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#define _GLIBCXX_PARALLEL_DECISION(__a, __b, __c, __d) { \
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if (__seq ## __d < __seq ## __a) \
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goto __s ## __d ## __a ## __b ## __c; \
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if (__seq ## __d < __seq ## __b) \
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goto __s ## __a ## __d ## __b ## __c; \
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if (__seq ## __d < __seq ## __c) \
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goto __s ## __a ## __b ## __d ## __c; \
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goto __s ## __a ## __b ## __c ## __d; }
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if (__seq0 <= __seq1)
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{
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if (__seq1 <= __seq2)
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_GLIBCXX_PARALLEL_DECISION(0,1,2,3)
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else
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if (__seq2 < __seq0)
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_GLIBCXX_PARALLEL_DECISION(2,0,1,3)
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else
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_GLIBCXX_PARALLEL_DECISION(0,2,1,3)
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}
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else
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{
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if (__seq1 <= __seq2)
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{
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if (__seq0 <= __seq2)
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_GLIBCXX_PARALLEL_DECISION(1,0,2,3)
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else
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_GLIBCXX_PARALLEL_DECISION(1,2,0,3)
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}
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else
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_GLIBCXX_PARALLEL_DECISION(2,1,0,3)
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}
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#define _GLIBCXX_PARALLEL_MERGE_4_CASE(__a, __b, __c, __d, \
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__c0, __c1, __c2) \
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__s ## __a ## __b ## __c ## __d: \
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if (__length == 0) goto __finish; \
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|
*__target = *__seq ## __a; \
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++__target; \
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--__length; \
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++__seq ## __a; \
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if (__seq ## __a __c0 __seq ## __b) \
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goto __s ## __a ## __b ## __c ## __d; \
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if (__seq ## __a __c1 __seq ## __c) \
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goto __s ## __b ## __a ## __c ## __d; \
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if (__seq ## __a __c2 __seq ## __d) \
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goto __s ## __b ## __c ## __a ## __d; \
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goto __s ## __b ## __c ## __d ## __a;
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_GLIBCXX_PARALLEL_MERGE_4_CASE(0, 1, 2, 3, <=, <=, <=);
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_GLIBCXX_PARALLEL_MERGE_4_CASE(0, 1, 3, 2, <=, <=, <=);
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_GLIBCXX_PARALLEL_MERGE_4_CASE(0, 2, 1, 3, <=, <=, <=);
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_GLIBCXX_PARALLEL_MERGE_4_CASE(0, 2, 3, 1, <=, <=, <=);
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_GLIBCXX_PARALLEL_MERGE_4_CASE(0, 3, 1, 2, <=, <=, <=);
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_GLIBCXX_PARALLEL_MERGE_4_CASE(0, 3, 2, 1, <=, <=, <=);
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_GLIBCXX_PARALLEL_MERGE_4_CASE(1, 0, 2, 3, < , <=, <=);
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_GLIBCXX_PARALLEL_MERGE_4_CASE(1, 0, 3, 2, < , <=, <=);
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_GLIBCXX_PARALLEL_MERGE_4_CASE(1, 2, 0, 3, <=, < , <=);
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_GLIBCXX_PARALLEL_MERGE_4_CASE(1, 2, 3, 0, <=, <=, < );
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_GLIBCXX_PARALLEL_MERGE_4_CASE(1, 3, 0, 2, <=, < , <=);
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_GLIBCXX_PARALLEL_MERGE_4_CASE(1, 3, 2, 0, <=, <=, < );
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_GLIBCXX_PARALLEL_MERGE_4_CASE(2, 0, 1, 3, < , < , <=);
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_GLIBCXX_PARALLEL_MERGE_4_CASE(2, 0, 3, 1, < , <=, < );
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_GLIBCXX_PARALLEL_MERGE_4_CASE(2, 1, 0, 3, < , < , <=);
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_GLIBCXX_PARALLEL_MERGE_4_CASE(2, 1, 3, 0, < , <=, < );
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_GLIBCXX_PARALLEL_MERGE_4_CASE(2, 3, 0, 1, <=, < , < );
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_GLIBCXX_PARALLEL_MERGE_4_CASE(2, 3, 1, 0, <=, < , < );
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_GLIBCXX_PARALLEL_MERGE_4_CASE(3, 0, 1, 2, < , < , < );
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_GLIBCXX_PARALLEL_MERGE_4_CASE(3, 0, 2, 1, < , < , < );
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_GLIBCXX_PARALLEL_MERGE_4_CASE(3, 1, 0, 2, < , < , < );
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_GLIBCXX_PARALLEL_MERGE_4_CASE(3, 1, 2, 0, < , < , < );
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_GLIBCXX_PARALLEL_MERGE_4_CASE(3, 2, 0, 1, < , < , < );
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_GLIBCXX_PARALLEL_MERGE_4_CASE(3, 2, 1, 0, < , < , < );
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#undef _GLIBCXX_PARALLEL_MERGE_4_CASE
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#undef _GLIBCXX_PARALLEL_DECISION
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|
|
__finish:
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;
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__seqs_begin[0].first = __seq0;
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|
__seqs_begin[1].first = __seq1;
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|
__seqs_begin[2].first = __seq2;
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|
__seqs_begin[3].first = __seq3;
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|
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return __target;
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}
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|
|
/** @brief Multi-way merging procedure for a high branching factor,
|
|
* guarded case.
|
|
*
|
|
* This merging variant uses a LoserTree class as selected by <tt>_LT</tt>.
|
|
*
|
|
* Stability is selected through the used LoserTree class <tt>_LT</tt>.
|
|
*
|
|
* At least one non-empty sequence is required.
|
|
*
|
|
* @param __seqs_begin Begin iterator of iterator pair input sequence.
|
|
* @param __seqs_end End iterator of iterator pair input sequence.
|
|
* @param __target Begin iterator of output sequence.
|
|
* @param __comp Comparator.
|
|
* @param __length Maximum length to merge, less equal than the
|
|
* total number of elements available.
|
|
*
|
|
* @return End iterator of output sequence.
|
|
*/
|
|
template<typename _LT,
|
|
typename _RAIterIterator,
|
|
typename _RAIter3,
|
|
typename _DifferenceTp,
|
|
typename _Compare>
|
|
_RAIter3
|
|
multiway_merge_loser_tree(_RAIterIterator __seqs_begin,
|
|
_RAIterIterator __seqs_end,
|
|
_RAIter3 __target,
|
|
_DifferenceTp __length, _Compare __comp)
|
|
{
|
|
_GLIBCXX_CALL(__length)
|
|
|
|
typedef _DifferenceTp _DifferenceType;
|
|
typedef typename std::iterator_traits<_RAIterIterator>
|
|
::difference_type _SeqNumber;
|
|
typedef typename std::iterator_traits<_RAIterIterator>
|
|
::value_type::first_type
|
|
_RAIter1;
|
|
typedef typename std::iterator_traits<_RAIter1>::value_type
|
|
_ValueType;
|
|
|
|
_SeqNumber __k = static_cast<_SeqNumber>(__seqs_end - __seqs_begin);
|
|
|
|
_LT __lt(__k, __comp);
|
|
|
|
// Default value for potentially non-default-constructible types.
|
|
_ValueType* __arbitrary_element = 0;
|
|
|
|
for (_SeqNumber __t = 0; __t < __k; ++__t)
|
|
{
|
|
if(!__arbitrary_element
|
|
&& _GLIBCXX_PARALLEL_LENGTH(__seqs_begin[__t]) > 0)
|
|
__arbitrary_element = &(*__seqs_begin[__t].first);
|
|
}
|
|
|
|
for (_SeqNumber __t = 0; __t < __k; ++__t)
|
|
{
|
|
if (__seqs_begin[__t].first == __seqs_begin[__t].second)
|
|
__lt.__insert_start(*__arbitrary_element, __t, true);
|
|
else
|
|
__lt.__insert_start(*__seqs_begin[__t].first, __t, false);
|
|
}
|
|
|
|
__lt.__init();
|
|
|
|
_SeqNumber __source;
|
|
|
|
for (_DifferenceType __i = 0; __i < __length; ++__i)
|
|
{
|
|
//take out
|
|
__source = __lt.__get_min_source();
|
|
|
|
*(__target++) = *(__seqs_begin[__source].first++);
|
|
|
|
// Feed.
|
|
if (__seqs_begin[__source].first == __seqs_begin[__source].second)
|
|
__lt.__delete_min_insert(*__arbitrary_element, true);
|
|
else
|
|
// Replace from same __source.
|
|
__lt.__delete_min_insert(*__seqs_begin[__source].first, false);
|
|
}
|
|
|
|
return __target;
|
|
}
|
|
|
|
/** @brief Multi-way merging procedure for a high branching factor,
|
|
* unguarded case.
|
|
*
|
|
* Merging is done using the LoserTree class <tt>_LT</tt>.
|
|
*
|
|
* Stability is selected by the used LoserTrees.
|
|
*
|
|
* @pre No input will run out of elements during the merge.
|
|
*
|
|
* @param __seqs_begin Begin iterator of iterator pair input sequence.
|
|
* @param __seqs_end End iterator of iterator pair input sequence.
|
|
* @param __target Begin iterator of output sequence.
|
|
* @param __comp Comparator.
|
|
* @param __length Maximum length to merge, less equal than the
|
|
* total number of elements available.
|
|
*
|
|
* @return End iterator of output sequence.
|
|
*/
|
|
template<typename _LT,
|
|
typename _RAIterIterator,
|
|
typename _RAIter3,
|
|
typename _DifferenceTp, typename _Compare>
|
|
_RAIter3
|
|
multiway_merge_loser_tree_unguarded(_RAIterIterator __seqs_begin,
|
|
_RAIterIterator __seqs_end,
|
|
_RAIter3 __target,
|
|
const typename std::iterator_traits<typename std::iterator_traits<
|
|
_RAIterIterator>::value_type::first_type>::value_type&
|
|
__sentinel,
|
|
_DifferenceTp __length,
|
|
_Compare __comp)
|
|
{
|
|
_GLIBCXX_CALL(__length)
|
|
typedef _DifferenceTp _DifferenceType;
|
|
|
|
typedef typename std::iterator_traits<_RAIterIterator>
|
|
::difference_type _SeqNumber;
|
|
typedef typename std::iterator_traits<_RAIterIterator>
|
|
::value_type::first_type
|
|
_RAIter1;
|
|
typedef typename std::iterator_traits<_RAIter1>::value_type
|
|
_ValueType;
|
|
|
|
_SeqNumber __k = __seqs_end - __seqs_begin;
|
|
|
|
_LT __lt(__k, __sentinel, __comp);
|
|
|
|
for (_SeqNumber __t = 0; __t < __k; ++__t)
|
|
{
|
|
#if _GLIBCXX_ASSERTIONS
|
|
_GLIBCXX_PARALLEL_ASSERT(__seqs_begin[__t].first
|
|
!= __seqs_begin[__t].second);
|
|
#endif
|
|
__lt.__insert_start(*__seqs_begin[__t].first, __t, false);
|
|
}
|
|
|
|
__lt.__init();
|
|
|
|
_SeqNumber __source;
|
|
|
|
#if _GLIBCXX_ASSERTIONS
|
|
_DifferenceType __i = 0;
|
|
#endif
|
|
|
|
_RAIter3 __target_end = __target + __length;
|
|
while (__target < __target_end)
|
|
{
|
|
// Take out.
|
|
__source = __lt.__get_min_source();
|
|
|
|
#if _GLIBCXX_ASSERTIONS
|
|
_GLIBCXX_PARALLEL_ASSERT(0 <= __source && __source < __k);
|
|
_GLIBCXX_PARALLEL_ASSERT(__i == 0
|
|
|| !__comp(*(__seqs_begin[__source].first), *(__target - 1)));
|
|
#endif
|
|
|
|
// Feed.
|
|
*(__target++) = *(__seqs_begin[__source].first++);
|
|
|
|
#if _GLIBCXX_ASSERTIONS
|
|
++__i;
|
|
#endif
|
|
// Replace from same __source.
|
|
__lt.__delete_min_insert(*__seqs_begin[__source].first, false);
|
|
}
|
|
|
|
return __target;
|
|
}
|
|
|
|
|
|
/** @brief Multi-way merging procedure for a high branching factor,
|
|
* requiring sentinels to exist.
|
|
*
|
|
* @param __stable The value must the same as for the used LoserTrees.
|
|
* @param UnguardedLoserTree _Loser Tree variant to use for the unguarded
|
|
* merging.
|
|
* @param GuardedLoserTree _Loser Tree variant to use for the guarded
|
|
* merging.
|
|
*
|
|
* @param __seqs_begin Begin iterator of iterator pair input sequence.
|
|
* @param __seqs_end End iterator of iterator pair input sequence.
|
|
* @param __target Begin iterator of output sequence.
|
|
* @param __comp Comparator.
|
|
* @param __length Maximum length to merge, less equal than the
|
|
* total number of elements available.
|
|
*
|
|
* @return End iterator of output sequence.
|
|
*/
|
|
template<typename UnguardedLoserTree,
|
|
typename _RAIterIterator,
|
|
typename _RAIter3,
|
|
typename _DifferenceTp,
|
|
typename _Compare>
|
|
_RAIter3
|
|
multiway_merge_loser_tree_sentinel(_RAIterIterator __seqs_begin,
|
|
_RAIterIterator __seqs_end,
|
|
_RAIter3 __target,
|
|
const typename std::iterator_traits<typename std::iterator_traits<
|
|
_RAIterIterator>::value_type::first_type>::value_type&
|
|
__sentinel,
|
|
_DifferenceTp __length,
|
|
_Compare __comp)
|
|
{
|
|
_GLIBCXX_CALL(__length)
|
|
|
|
typedef _DifferenceTp _DifferenceType;
|
|
typedef std::iterator_traits<_RAIterIterator> _TraitsType;
|
|
typedef typename std::iterator_traits<_RAIterIterator>
|
|
::value_type::first_type
|
|
_RAIter1;
|
|
typedef typename std::iterator_traits<_RAIter1>::value_type
|
|
_ValueType;
|
|
|
|
_RAIter3 __target_end;
|
|
|
|
for (_RAIterIterator __s = __seqs_begin; __s != __seqs_end; ++__s)
|
|
// Move the sequence ends to the sentinel. This has the
|
|
// effect that the sentinel appears to be within the sequence. Then,
|
|
// we can use the unguarded variant if we merge out as many
|
|
// non-sentinel elements as we have.
|
|
++((*__s).second);
|
|
|
|
__target_end = multiway_merge_loser_tree_unguarded<UnguardedLoserTree>
|
|
(__seqs_begin, __seqs_end, __target, __sentinel, __length, __comp);
|
|
|
|
#if _GLIBCXX_ASSERTIONS
|
|
_GLIBCXX_PARALLEL_ASSERT(__target_end == __target + __length);
|
|
_GLIBCXX_PARALLEL_ASSERT(__is_sorted(__target, __target_end, __comp));
|
|
#endif
|
|
|
|
// Restore the sequence ends so the sentinels are not contained in the
|
|
// sequence any more (see comment in loop above).
|
|
for (_RAIterIterator __s = __seqs_begin; __s != __seqs_end; ++__s)
|
|
--((*__s).second);
|
|
|
|
return __target_end;
|
|
}
|
|
|
|
/**
|
|
* @brief Traits for determining whether the loser tree should
|
|
* use pointers or copies.
|
|
*
|
|
* The field "_M_use_pointer" is used to determine whether to use pointers
|
|
* in he loser trees or whether to copy the values into the loser tree.
|
|
*
|
|
* The default behavior is to use pointers if the data type is 4 times as
|
|
* big as the pointer to it.
|
|
*
|
|
* Specialize for your data type to customize the behavior.
|
|
*
|
|
* Example:
|
|
*
|
|
* template<>
|
|
* struct _LoserTreeTraits<int>
|
|
* { static const bool _M_use_pointer = false; };
|
|
*
|
|
* template<>
|
|
* struct _LoserTreeTraits<heavyweight_type>
|
|
* { static const bool _M_use_pointer = true; };
|
|
*
|
|
* @param _Tp type to give the loser tree traits for.
|
|
*/
|
|
template <typename _Tp>
|
|
struct _LoserTreeTraits
|
|
{
|
|
/**
|
|
* @brief True iff to use pointers instead of values in loser trees.
|
|
*
|
|
* The default behavior is to use pointers if the data type is four
|
|
* times as big as the pointer to it.
|
|
*/
|
|
static const bool _M_use_pointer = (sizeof(_Tp) > 4 * sizeof(_Tp*));
|
|
};
|
|
|
|
/**
|
|
* @brief Switch for 3-way merging with __sentinels turned off.
|
|
*
|
|
* Note that 3-way merging is always stable!
|
|
*/
|
|
template<bool __sentinels /*default == false*/,
|
|
typename _RAIterIterator,
|
|
typename _RAIter3,
|
|
typename _DifferenceTp,
|
|
typename _Compare>
|
|
struct __multiway_merge_3_variant_sentinel_switch
|
|
{
|
|
_RAIter3
|
|
operator()(_RAIterIterator __seqs_begin,
|
|
_RAIterIterator __seqs_end,
|
|
_RAIter3 __target,
|
|
_DifferenceTp __length, _Compare __comp)
|
|
{ return multiway_merge_3_variant<_GuardedIterator>
|
|
(__seqs_begin, __seqs_end, __target, __length, __comp); }
|
|
};
|
|
|
|
/**
|
|
* @brief Switch for 3-way merging with __sentinels turned on.
|
|
*
|
|
* Note that 3-way merging is always stable!
|
|
*/
|
|
template<typename _RAIterIterator,
|
|
typename _RAIter3,
|
|
typename _DifferenceTp,
|
|
typename _Compare>
|
|
struct __multiway_merge_3_variant_sentinel_switch<true, _RAIterIterator,
|
|
_RAIter3, _DifferenceTp,
|
|
_Compare>
|
|
{
|
|
_RAIter3
|
|
operator()(_RAIterIterator __seqs_begin,
|
|
_RAIterIterator __seqs_end,
|
|
_RAIter3 __target,
|
|
_DifferenceTp __length, _Compare __comp)
|
|
{ return multiway_merge_3_variant<_UnguardedIterator>
|
|
(__seqs_begin, __seqs_end, __target, __length, __comp); }
|
|
};
|
|
|
|
/**
|
|
* @brief Switch for 4-way merging with __sentinels turned off.
|
|
*
|
|
* Note that 4-way merging is always stable!
|
|
*/
|
|
template<bool __sentinels /*default == false*/,
|
|
typename _RAIterIterator,
|
|
typename _RAIter3,
|
|
typename _DifferenceTp,
|
|
typename _Compare>
|
|
struct __multiway_merge_4_variant_sentinel_switch
|
|
{
|
|
_RAIter3
|
|
operator()(_RAIterIterator __seqs_begin,
|
|
_RAIterIterator __seqs_end,
|
|
_RAIter3 __target,
|
|
_DifferenceTp __length, _Compare __comp)
|
|
{ return multiway_merge_4_variant<_GuardedIterator>
|
|
(__seqs_begin, __seqs_end, __target, __length, __comp); }
|
|
};
|
|
|
|
/**
|
|
* @brief Switch for 4-way merging with __sentinels turned on.
|
|
*
|
|
* Note that 4-way merging is always stable!
|
|
*/
|
|
template<typename _RAIterIterator,
|
|
typename _RAIter3,
|
|
typename _DifferenceTp,
|
|
typename _Compare>
|
|
struct __multiway_merge_4_variant_sentinel_switch<true, _RAIterIterator,
|
|
_RAIter3, _DifferenceTp,
|
|
_Compare>
|
|
{
|
|
_RAIter3
|
|
operator()(_RAIterIterator __seqs_begin,
|
|
_RAIterIterator __seqs_end,
|
|
_RAIter3 __target,
|
|
_DifferenceTp __length, _Compare __comp)
|
|
{ return multiway_merge_4_variant<_UnguardedIterator>
|
|
(__seqs_begin, __seqs_end, __target, __length, __comp); }
|
|
};
|
|
|
|
/**
|
|
* @brief Switch for k-way merging with __sentinels turned on.
|
|
*/
|
|
template<bool __sentinels,
|
|
bool __stable,
|
|
typename _RAIterIterator,
|
|
typename _RAIter3,
|
|
typename _DifferenceTp,
|
|
typename _Compare>
|
|
struct __multiway_merge_k_variant_sentinel_switch
|
|
{
|
|
_RAIter3
|
|
operator()(_RAIterIterator __seqs_begin,
|
|
_RAIterIterator __seqs_end,
|
|
_RAIter3 __target,
|
|
const typename std::iterator_traits<typename std::iterator_traits<
|
|
_RAIterIterator>::value_type::first_type>::value_type&
|
|
__sentinel,
|
|
_DifferenceTp __length, _Compare __comp)
|
|
{
|
|
typedef typename std::iterator_traits<_RAIterIterator>
|
|
::value_type::first_type
|
|
_RAIter1;
|
|
typedef typename std::iterator_traits<_RAIter1>::value_type
|
|
_ValueType;
|
|
|
|
return multiway_merge_loser_tree_sentinel<
|
|
typename __gnu_cxx::__conditional_type<
|
|
_LoserTreeTraits<_ValueType>::_M_use_pointer,
|
|
_LoserTreePointerUnguarded<__stable, _ValueType, _Compare>,
|
|
_LoserTreeUnguarded<__stable, _ValueType, _Compare>
|
|
>::__type>
|
|
(__seqs_begin, __seqs_end, __target, __sentinel, __length, __comp);
|
|
}
|
|
};
|
|
|
|
/**
|
|
* @brief Switch for k-way merging with __sentinels turned off.
|
|
*/
|
|
template<bool __stable,
|
|
typename _RAIterIterator,
|
|
typename _RAIter3,
|
|
typename _DifferenceTp,
|
|
typename _Compare>
|
|
struct __multiway_merge_k_variant_sentinel_switch<false, __stable,
|
|
_RAIterIterator,
|
|
_RAIter3, _DifferenceTp,
|
|
_Compare>
|
|
{
|
|
_RAIter3
|
|
operator()(_RAIterIterator __seqs_begin,
|
|
_RAIterIterator __seqs_end,
|
|
_RAIter3 __target,
|
|
const typename std::iterator_traits<typename std::iterator_traits<
|
|
_RAIterIterator>::value_type::first_type>::value_type&
|
|
__sentinel,
|
|
_DifferenceTp __length, _Compare __comp)
|
|
{
|
|
typedef typename std::iterator_traits<_RAIterIterator>
|
|
::value_type::first_type
|
|
_RAIter1;
|
|
typedef typename std::iterator_traits<_RAIter1>::value_type
|
|
_ValueType;
|
|
|
|
return multiway_merge_loser_tree<
|
|
typename __gnu_cxx::__conditional_type<
|
|
_LoserTreeTraits<_ValueType>::_M_use_pointer,
|
|
_LoserTreePointer<__stable, _ValueType, _Compare>,
|
|
_LoserTree<__stable, _ValueType, _Compare>
|
|
>::__type >(__seqs_begin, __seqs_end, __target, __length, __comp);
|
|
}
|
|
};
|
|
|
|
/** @brief Sequential multi-way merging switch.
|
|
*
|
|
* The _GLIBCXX_PARALLEL_DECISION is based on the branching factor and
|
|
* runtime settings.
|
|
* @param __seqs_begin Begin iterator of iterator pair input sequence.
|
|
* @param __seqs_end End iterator of iterator pair input sequence.
|
|
* @param __target Begin iterator of output sequence.
|
|
* @param __comp Comparator.
|
|
* @param __length Maximum length to merge, possibly larger than the
|
|
* number of elements available.
|
|
* @param __stable Stable merging incurs a performance penalty.
|
|
* @param __sentinel The sequences have __a __sentinel element.
|
|
* @return End iterator of output sequence. */
|
|
template<bool __stable,
|
|
bool __sentinels,
|
|
typename _RAIterIterator,
|
|
typename _RAIter3,
|
|
typename _DifferenceTp,
|
|
typename _Compare>
|
|
_RAIter3
|
|
__sequential_multiway_merge(_RAIterIterator __seqs_begin,
|
|
_RAIterIterator __seqs_end,
|
|
_RAIter3 __target,
|
|
const typename std::iterator_traits<typename std::iterator_traits<
|
|
_RAIterIterator>::value_type::first_type>::value_type&
|
|
__sentinel,
|
|
_DifferenceTp __length, _Compare __comp)
|
|
{
|
|
_GLIBCXX_CALL(__length)
|
|
|
|
typedef _DifferenceTp _DifferenceType;
|
|
typedef typename std::iterator_traits<_RAIterIterator>
|
|
::difference_type _SeqNumber;
|
|
typedef typename std::iterator_traits<_RAIterIterator>
|
|
::value_type::first_type
|
|
_RAIter1;
|
|
typedef typename std::iterator_traits<_RAIter1>::value_type
|
|
_ValueType;
|
|
|
|
#if _GLIBCXX_ASSERTIONS
|
|
for (_RAIterIterator __s = __seqs_begin; __s != __seqs_end; ++__s)
|
|
{
|
|
_GLIBCXX_PARALLEL_ASSERT(__is_sorted((*__s).first,
|
|
(*__s).second, __comp));
|
|
}
|
|
#endif
|
|
|
|
_DifferenceTp __total_length = 0;
|
|
for (_RAIterIterator __s = __seqs_begin; __s != __seqs_end; ++__s)
|
|
__total_length += _GLIBCXX_PARALLEL_LENGTH(*__s);
|
|
|
|
__length = std::min<_DifferenceTp>(__length, __total_length);
|
|
|
|
if(__length == 0)
|
|
return __target;
|
|
|
|
_RAIter3 __return_target = __target;
|
|
_SeqNumber __k = static_cast<_SeqNumber>(__seqs_end - __seqs_begin);
|
|
|
|
switch (__k)
|
|
{
|
|
case 0:
|
|
break;
|
|
case 1:
|
|
__return_target = std::copy(__seqs_begin[0].first,
|
|
__seqs_begin[0].first + __length,
|
|
__target);
|
|
__seqs_begin[0].first += __length;
|
|
break;
|
|
case 2:
|
|
__return_target = __merge_advance(__seqs_begin[0].first,
|
|
__seqs_begin[0].second,
|
|
__seqs_begin[1].first,
|
|
__seqs_begin[1].second,
|
|
__target, __length, __comp);
|
|
break;
|
|
case 3:
|
|
__return_target = __multiway_merge_3_variant_sentinel_switch
|
|
<__sentinels, _RAIterIterator, _RAIter3, _DifferenceTp, _Compare>()
|
|
(__seqs_begin, __seqs_end, __target, __length, __comp);
|
|
break;
|
|
case 4:
|
|
__return_target = __multiway_merge_4_variant_sentinel_switch
|
|
<__sentinels, _RAIterIterator, _RAIter3, _DifferenceTp, _Compare>()
|
|
(__seqs_begin, __seqs_end, __target, __length, __comp);
|
|
break;
|
|
default:
|
|
__return_target = __multiway_merge_k_variant_sentinel_switch
|
|
<__sentinels, __stable, _RAIterIterator, _RAIter3, _DifferenceTp,
|
|
_Compare>()
|
|
(__seqs_begin, __seqs_end, __target, __sentinel, __length, __comp);
|
|
break;
|
|
}
|
|
#if _GLIBCXX_ASSERTIONS
|
|
_GLIBCXX_PARALLEL_ASSERT(
|
|
__is_sorted(__target, __target + __length, __comp));
|
|
#endif
|
|
|
|
return __return_target;
|
|
}
|
|
|
|
/**
|
|
* @brief Stable sorting functor.
|
|
*
|
|
* Used to reduce code instanciation in multiway_merge_sampling_splitting.
|
|
*/
|
|
template<bool __stable, class _RAIter, class _StrictWeakOrdering>
|
|
struct _SamplingSorter
|
|
{
|
|
void
|
|
operator()(_RAIter __first, _RAIter __last, _StrictWeakOrdering __comp)
|
|
{ __gnu_sequential::stable_sort(__first, __last, __comp); }
|
|
};
|
|
|
|
/**
|
|
* @brief Non-__stable sorting functor.
|
|
*
|
|
* Used to reduce code instantiation in multiway_merge_sampling_splitting.
|
|
*/
|
|
template<class _RAIter, class _StrictWeakOrdering>
|
|
struct _SamplingSorter<false, _RAIter, _StrictWeakOrdering>
|
|
{
|
|
void
|
|
operator()(_RAIter __first, _RAIter __last, _StrictWeakOrdering __comp)
|
|
{ __gnu_sequential::sort(__first, __last, __comp); }
|
|
};
|
|
|
|
/**
|
|
* @brief Sampling based splitting for parallel multiway-merge routine.
|
|
*/
|
|
template<bool __stable,
|
|
typename _RAIterIterator,
|
|
typename _Compare,
|
|
typename _DifferenceType>
|
|
void
|
|
multiway_merge_sampling_splitting(_RAIterIterator __seqs_begin,
|
|
_RAIterIterator __seqs_end,
|
|
_DifferenceType __length,
|
|
_DifferenceType __total_length,
|
|
_Compare __comp,
|
|
std::vector<std::pair<_DifferenceType, _DifferenceType> > *__pieces)
|
|
{
|
|
typedef typename std::iterator_traits<_RAIterIterator>
|
|
::difference_type _SeqNumber;
|
|
typedef typename std::iterator_traits<_RAIterIterator>
|
|
::value_type::first_type
|
|
_RAIter1;
|
|
typedef typename std::iterator_traits<_RAIter1>::value_type
|
|
_ValueType;
|
|
|
|
// __k sequences.
|
|
_SeqNumber __k = static_cast<_SeqNumber>(__seqs_end - __seqs_begin);
|
|
|
|
_ThreadIndex __num_threads = omp_get_num_threads();
|
|
|
|
_DifferenceType __num_samples =
|
|
__gnu_parallel::_Settings::get().merge_oversampling * __num_threads;
|
|
|
|
_ValueType* __samples = static_cast<_ValueType*>
|
|
(::operator new(sizeof(_ValueType) * __k * __num_samples));
|
|
// Sample.
|
|
for (_SeqNumber __s = 0; __s < __k; ++__s)
|
|
for (_DifferenceType __i = 0; __i < __num_samples; ++__i)
|
|
{
|
|
_DifferenceType sample_index = static_cast<_DifferenceType>
|
|
(_GLIBCXX_PARALLEL_LENGTH(__seqs_begin[__s])
|
|
* (double(__i + 1) / (__num_samples + 1))
|
|
* (double(__length) / __total_length));
|
|
new(&(__samples[__s * __num_samples + __i]))
|
|
_ValueType(__seqs_begin[__s].first[sample_index]);
|
|
}
|
|
|
|
// Sort stable or non-stable, depending on value of template parameter
|
|
// "__stable".
|
|
_SamplingSorter<__stable, _ValueType*, _Compare>()
|
|
(__samples, __samples + (__num_samples * __k), __comp);
|
|
|
|
for (_ThreadIndex __slab = 0; __slab < __num_threads; ++__slab)
|
|
// For each slab / processor.
|
|
for (_SeqNumber __seq = 0; __seq < __k; ++__seq)
|
|
{
|
|
// For each sequence.
|
|
if (__slab > 0)
|
|
__pieces[__slab][__seq].first = std::upper_bound
|
|
(__seqs_begin[__seq].first, __seqs_begin[__seq].second,
|
|
__samples[__num_samples * __k * __slab / __num_threads],
|
|
__comp)
|
|
- __seqs_begin[__seq].first;
|
|
else
|
|
// Absolute beginning.
|
|
__pieces[__slab][__seq].first = 0;
|
|
if ((__slab + 1) < __num_threads)
|
|
__pieces[__slab][__seq].second = std::upper_bound
|
|
(__seqs_begin[__seq].first, __seqs_begin[__seq].second,
|
|
__samples[__num_samples * __k * (__slab + 1) / __num_threads],
|
|
__comp)
|
|
- __seqs_begin[__seq].first;
|
|
else
|
|
// Absolute end.
|
|
__pieces[__slab][__seq].second =
|
|
_GLIBCXX_PARALLEL_LENGTH(__seqs_begin[__seq]);
|
|
}
|
|
::operator delete(__samples);
|
|
}
|
|
|
|
/**
|
|
* @brief Exact splitting for parallel multiway-merge routine.
|
|
*
|
|
* None of the passed sequences may be empty.
|
|
*/
|
|
template<bool __stable,
|
|
typename _RAIterIterator,
|
|
typename _Compare,
|
|
typename _DifferenceType>
|
|
void
|
|
multiway_merge_exact_splitting(_RAIterIterator __seqs_begin,
|
|
_RAIterIterator __seqs_end,
|
|
_DifferenceType __length,
|
|
_DifferenceType __total_length,
|
|
_Compare __comp,
|
|
std::vector<std::pair<_DifferenceType, _DifferenceType> > *__pieces)
|
|
{
|
|
typedef typename std::iterator_traits<_RAIterIterator>
|
|
::difference_type _SeqNumber;
|
|
typedef typename std::iterator_traits<_RAIterIterator>
|
|
::value_type::first_type
|
|
_RAIter1;
|
|
|
|
const bool __tight = (__total_length == __length);
|
|
|
|
// __k sequences.
|
|
const _SeqNumber __k = __seqs_end - __seqs_begin;
|
|
|
|
const _ThreadIndex __num_threads = omp_get_num_threads();
|
|
|
|
// (Settings::multiway_merge_splitting
|
|
// == __gnu_parallel::_Settings::EXACT).
|
|
std::vector<_RAIter1>* __offsets =
|
|
new std::vector<_RAIter1>[__num_threads];
|
|
std::vector<std::pair<_RAIter1, _RAIter1> > __se(__k);
|
|
|
|
copy(__seqs_begin, __seqs_end, __se.begin());
|
|
|
|
_DifferenceType* __borders =
|
|
new _DifferenceType[__num_threads + 1];
|
|
equally_split(__length, __num_threads, __borders);
|
|
|
|
for (_ThreadIndex __s = 0; __s < (__num_threads - 1); ++__s)
|
|
{
|
|
__offsets[__s].resize(__k);
|
|
multiseq_partition(__se.begin(), __se.end(), __borders[__s + 1],
|
|
__offsets[__s].begin(), __comp);
|
|
|
|
// Last one also needed and available.
|
|
if (!__tight)
|
|
{
|
|
__offsets[__num_threads - 1].resize(__k);
|
|
multiseq_partition(__se.begin(), __se.end(),
|
|
_DifferenceType(__length),
|
|
__offsets[__num_threads - 1].begin(),
|
|
__comp);
|
|
}
|
|
}
|
|
delete[] __borders;
|
|
|
|
for (_ThreadIndex __slab = 0; __slab < __num_threads; ++__slab)
|
|
{
|
|
// For each slab / processor.
|
|
for (_SeqNumber __seq = 0; __seq < __k; ++__seq)
|
|
{
|
|
// For each sequence.
|
|
if (__slab == 0)
|
|
{
|
|
// Absolute beginning.
|
|
__pieces[__slab][__seq].first = 0;
|
|
}
|
|
else
|
|
__pieces[__slab][__seq].first =
|
|
__pieces[__slab - 1][__seq].second;
|
|
if (!__tight || __slab < (__num_threads - 1))
|
|
__pieces[__slab][__seq].second =
|
|
__offsets[__slab][__seq] - __seqs_begin[__seq].first;
|
|
else
|
|
{
|
|
// __slab == __num_threads - 1
|
|
__pieces[__slab][__seq].second =
|
|
_GLIBCXX_PARALLEL_LENGTH(__seqs_begin[__seq]);
|
|
}
|
|
}
|
|
}
|
|
delete[] __offsets;
|
|
}
|
|
|
|
/** @brief Parallel multi-way merge routine.
|
|
*
|
|
* The _GLIBCXX_PARALLEL_DECISION is based on the branching factor
|
|
* and runtime settings.
|
|
*
|
|
* Must not be called if the number of sequences is 1.
|
|
*
|
|
* @param _Splitter functor to split input (either __exact or sampling based)
|
|
*
|
|
* @param __seqs_begin Begin iterator of iterator pair input sequence.
|
|
* @param __seqs_end End iterator of iterator pair input sequence.
|
|
* @param __target Begin iterator of output sequence.
|
|
* @param __comp Comparator.
|
|
* @param __length Maximum length to merge, possibly larger than the
|
|
* number of elements available.
|
|
* @param __stable Stable merging incurs a performance penalty.
|
|
* @param __sentinel Ignored.
|
|
* @return End iterator of output sequence.
|
|
*/
|
|
template<bool __stable,
|
|
bool __sentinels,
|
|
typename _RAIterIterator,
|
|
typename _RAIter3,
|
|
typename _DifferenceTp,
|
|
typename _Splitter,
|
|
typename _Compare>
|
|
_RAIter3
|
|
parallel_multiway_merge(_RAIterIterator __seqs_begin,
|
|
_RAIterIterator __seqs_end,
|
|
_RAIter3 __target,
|
|
_Splitter __splitter,
|
|
_DifferenceTp __length,
|
|
_Compare __comp,
|
|
_ThreadIndex __num_threads)
|
|
{
|
|
#if _GLIBCXX_ASSERTIONS
|
|
_GLIBCXX_PARALLEL_ASSERT(__seqs_end - __seqs_begin > 1);
|
|
#endif
|
|
|
|
_GLIBCXX_CALL(__length)
|
|
|
|
typedef _DifferenceTp _DifferenceType;
|
|
typedef typename std::iterator_traits<_RAIterIterator>
|
|
::difference_type _SeqNumber;
|
|
typedef typename std::iterator_traits<_RAIterIterator>
|
|
::value_type::first_type
|
|
_RAIter1;
|
|
typedef typename
|
|
std::iterator_traits<_RAIter1>::value_type _ValueType;
|
|
|
|
// Leave only non-empty sequences.
|
|
typedef std::pair<_RAIter1, _RAIter1> seq_type;
|
|
seq_type* __ne_seqs = new seq_type[__seqs_end - __seqs_begin];
|
|
_SeqNumber __k = 0;
|
|
_DifferenceType __total_length = 0;
|
|
for (_RAIterIterator __raii = __seqs_begin;
|
|
__raii != __seqs_end; ++__raii)
|
|
{
|
|
_DifferenceTp __seq_length = _GLIBCXX_PARALLEL_LENGTH(*__raii);
|
|
if(__seq_length > 0)
|
|
{
|
|
__total_length += __seq_length;
|
|
__ne_seqs[__k++] = *__raii;
|
|
}
|
|
}
|
|
|
|
_GLIBCXX_CALL(__total_length)
|
|
|
|
__length = std::min<_DifferenceTp>(__length, __total_length);
|
|
|
|
if (__total_length == 0 || __k == 0)
|
|
{
|
|
delete[] __ne_seqs;
|
|
return __target;
|
|
}
|
|
|
|
std::vector<std::pair<_DifferenceType, _DifferenceType> >* __pieces;
|
|
|
|
__num_threads = static_cast<_ThreadIndex>
|
|
(std::min<_DifferenceType>(__num_threads, __total_length));
|
|
|
|
# pragma omp parallel num_threads (__num_threads)
|
|
{
|
|
# pragma omp single
|
|
{
|
|
__num_threads = omp_get_num_threads();
|
|
// Thread __t will have to merge pieces[__iam][0..__k - 1]
|
|
__pieces = new std::vector<
|
|
std::pair<_DifferenceType, _DifferenceType> >[__num_threads];
|
|
for (_ThreadIndex __s = 0; __s < __num_threads; ++__s)
|
|
__pieces[__s].resize(__k);
|
|
|
|
_DifferenceType __num_samples =
|
|
__gnu_parallel::_Settings::get().merge_oversampling
|
|
* __num_threads;
|
|
|
|
__splitter(__ne_seqs, __ne_seqs + __k, __length, __total_length,
|
|
__comp, __pieces);
|
|
} //single
|
|
|
|
_ThreadIndex __iam = omp_get_thread_num();
|
|
|
|
_DifferenceType __target_position = 0;
|
|
|
|
for (_SeqNumber __c = 0; __c < __k; ++__c)
|
|
__target_position += __pieces[__iam][__c].first;
|
|
|
|
seq_type* __chunks = new seq_type[__k];
|
|
|
|
for (_SeqNumber __s = 0; __s < __k; ++__s)
|
|
__chunks[__s] = std::make_pair(__ne_seqs[__s].first
|
|
+ __pieces[__iam][__s].first,
|
|
__ne_seqs[__s].first
|
|
+ __pieces[__iam][__s].second);
|
|
|
|
if(__length > __target_position)
|
|
__sequential_multiway_merge<__stable, __sentinels>
|
|
(__chunks, __chunks + __k, __target + __target_position,
|
|
*(__seqs_begin->second), __length - __target_position, __comp);
|
|
|
|
delete[] __chunks;
|
|
} // parallel
|
|
|
|
#if _GLIBCXX_ASSERTIONS
|
|
_GLIBCXX_PARALLEL_ASSERT(
|
|
__is_sorted(__target, __target + __length, __comp));
|
|
#endif
|
|
|
|
__k = 0;
|
|
// Update ends of sequences.
|
|
for (_RAIterIterator __raii = __seqs_begin;
|
|
__raii != __seqs_end; ++__raii)
|
|
{
|
|
_DifferenceTp __length = _GLIBCXX_PARALLEL_LENGTH(*__raii);
|
|
if(__length > 0)
|
|
(*__raii).first += __pieces[__num_threads - 1][__k++].second;
|
|
}
|
|
|
|
delete[] __pieces;
|
|
delete[] __ne_seqs;
|
|
|
|
return __target + __length;
|
|
}
|
|
|
|
/**
|
|
* @brief Multiway Merge Frontend.
|
|
*
|
|
* Merge the sequences specified by seqs_begin and __seqs_end into
|
|
* __target. __seqs_begin and __seqs_end must point to a sequence of
|
|
* pairs. These pairs must contain an iterator to the beginning
|
|
* of a sequence in their first entry and an iterator the _M_end of
|
|
* the same sequence in their second entry.
|
|
*
|
|
* Ties are broken arbitrarily. See stable_multiway_merge for a variant
|
|
* that breaks ties by sequence number but is slower.
|
|
*
|
|
* The first entries of the pairs (i.e. the begin iterators) will be moved
|
|
* forward.
|
|
*
|
|
* The output sequence has to provide enough space for all elements
|
|
* that are written to it.
|
|
*
|
|
* This function will merge the input sequences:
|
|
*
|
|
* - not stable
|
|
* - parallel, depending on the input size and Settings
|
|
* - using sampling for splitting
|
|
* - not using sentinels
|
|
*
|
|
* Example:
|
|
*
|
|
* <pre>
|
|
* int sequences[10][10];
|
|
* for (int __i = 0; __i < 10; ++__i)
|
|
* for (int __j = 0; __i < 10; ++__j)
|
|
* sequences[__i][__j] = __j;
|
|
*
|
|
* int __out[33];
|
|
* std::vector<std::pair<int*> > seqs;
|
|
* for (int __i = 0; __i < 10; ++__i)
|
|
* { seqs.push(std::make_pair<int*>(sequences[__i],
|
|
* sequences[__i] + 10)) }
|
|
*
|
|
* multiway_merge(seqs.begin(), seqs.end(), __target, std::less<int>(), 33);
|
|
* </pre>
|
|
*
|
|
* @see stable_multiway_merge
|
|
*
|
|
* @pre All input sequences must be sorted.
|
|
* @pre Target must provide enough space to merge out length elements or
|
|
* the number of elements in all sequences, whichever is smaller.
|
|
*
|
|
* @post [__target, return __value) contains merged __elements from the
|
|
* input sequences.
|
|
* @post return __value - __target = min(__length, number of elements in all
|
|
* sequences).
|
|
*
|
|
* @param _RAIterPairIterator iterator over sequence
|
|
* of pairs of iterators
|
|
* @param _RAIterOut iterator over target sequence
|
|
* @param _DifferenceTp difference type for the sequence
|
|
* @param _Compare strict weak ordering type to compare elements
|
|
* in sequences
|
|
*
|
|
* @param __seqs_begin __begin of sequence __sequence
|
|
* @param __seqs_end _M_end of sequence __sequence
|
|
* @param __target target sequence to merge to.
|
|
* @param __comp strict weak ordering to use for element comparison.
|
|
* @param __length Maximum length to merge, possibly larger than the
|
|
* number of elements available.
|
|
*
|
|
* @return _M_end iterator of output sequence
|
|
*/
|
|
// multiway_merge
|
|
// public interface
|
|
template<typename _RAIterPairIterator,
|
|
typename _RAIterOut,
|
|
typename _DifferenceTp,
|
|
typename _Compare>
|
|
_RAIterOut
|
|
multiway_merge(_RAIterPairIterator __seqs_begin,
|
|
_RAIterPairIterator __seqs_end,
|
|
_RAIterOut __target,
|
|
_DifferenceTp __length, _Compare __comp,
|
|
__gnu_parallel::sequential_tag)
|
|
{
|
|
typedef _DifferenceTp _DifferenceType;
|
|
_GLIBCXX_CALL(__seqs_end - __seqs_begin)
|
|
|
|
// catch special case: no sequences
|
|
if (__seqs_begin == __seqs_end)
|
|
return __target;
|
|
|
|
// Execute multiway merge *sequentially*.
|
|
return __sequential_multiway_merge
|
|
</* __stable = */ false, /* __sentinels = */ false>
|
|
(__seqs_begin, __seqs_end, __target,
|
|
*(__seqs_begin->second), __length, __comp);
|
|
}
|
|
|
|
// public interface
|
|
template<typename _RAIterPairIterator,
|
|
typename _RAIterOut,
|
|
typename _DifferenceTp,
|
|
typename _Compare>
|
|
_RAIterOut
|
|
multiway_merge(_RAIterPairIterator __seqs_begin,
|
|
_RAIterPairIterator __seqs_end,
|
|
_RAIterOut __target,
|
|
_DifferenceTp __length, _Compare __comp,
|
|
__gnu_parallel::exact_tag __tag)
|
|
{
|
|
typedef _DifferenceTp _DifferenceType;
|
|
_GLIBCXX_CALL(__seqs_end - __seqs_begin)
|
|
|
|
// catch special case: no sequences
|
|
if (__seqs_begin == __seqs_end)
|
|
return __target;
|
|
|
|
// Execute merge; maybe parallel, depending on the number of merged
|
|
// elements and the number of sequences and global thresholds in
|
|
// Settings.
|
|
if ((__seqs_end - __seqs_begin > 1)
|
|
&& _GLIBCXX_PARALLEL_CONDITION(
|
|
((__seqs_end - __seqs_begin) >=
|
|
__gnu_parallel::_Settings::get().multiway_merge_minimal_k)
|
|
&& ((_SequenceIndex)__length >=
|
|
__gnu_parallel::_Settings::get().multiway_merge_minimal_n)))
|
|
return parallel_multiway_merge
|
|
</* __stable = */ false, /* __sentinels = */ false>
|
|
(__seqs_begin, __seqs_end, __target,
|
|
multiway_merge_exact_splitting</* __stable = */ false,
|
|
typename std::iterator_traits<_RAIterPairIterator>
|
|
::value_type*, _Compare, _DifferenceTp>,
|
|
static_cast<_DifferenceType>(__length), __comp,
|
|
__tag.__get_num_threads());
|
|
else
|
|
return __sequential_multiway_merge
|
|
</* __stable = */ false, /* __sentinels = */ false>
|
|
(__seqs_begin, __seqs_end, __target,
|
|
*(__seqs_begin->second), __length, __comp);
|
|
}
|
|
|
|
// public interface
|
|
template<typename _RAIterPairIterator,
|
|
typename _RAIterOut,
|
|
typename _DifferenceTp,
|
|
typename _Compare>
|
|
_RAIterOut
|
|
multiway_merge(_RAIterPairIterator __seqs_begin,
|
|
_RAIterPairIterator __seqs_end,
|
|
_RAIterOut __target,
|
|
_DifferenceTp __length, _Compare __comp,
|
|
__gnu_parallel::sampling_tag __tag)
|
|
{
|
|
typedef _DifferenceTp _DifferenceType;
|
|
_GLIBCXX_CALL(__seqs_end - __seqs_begin)
|
|
|
|
// catch special case: no sequences
|
|
if (__seqs_begin == __seqs_end)
|
|
return __target;
|
|
|
|
// Execute merge; maybe parallel, depending on the number of merged
|
|
// elements and the number of sequences and global thresholds in
|
|
// Settings.
|
|
if ((__seqs_end - __seqs_begin > 1)
|
|
&& _GLIBCXX_PARALLEL_CONDITION(
|
|
((__seqs_end - __seqs_begin) >=
|
|
__gnu_parallel::_Settings::get().multiway_merge_minimal_k)
|
|
&& ((_SequenceIndex)__length >=
|
|
__gnu_parallel::_Settings::get().multiway_merge_minimal_n)))
|
|
return parallel_multiway_merge
|
|
</* __stable = */ false, /* __sentinels = */ false>
|
|
(__seqs_begin, __seqs_end, __target,
|
|
multiway_merge_exact_splitting</* __stable = */ false,
|
|
typename std::iterator_traits<_RAIterPairIterator>
|
|
::value_type*, _Compare, _DifferenceTp>,
|
|
static_cast<_DifferenceType>(__length), __comp,
|
|
__tag.__get_num_threads());
|
|
else
|
|
return __sequential_multiway_merge
|
|
</* __stable = */ false, /* __sentinels = */ false>
|
|
(__seqs_begin, __seqs_end, __target,
|
|
*(__seqs_begin->second), __length, __comp);
|
|
}
|
|
|
|
// public interface
|
|
template<typename _RAIterPairIterator,
|
|
typename _RAIterOut,
|
|
typename _DifferenceTp,
|
|
typename _Compare>
|
|
_RAIterOut
|
|
multiway_merge(_RAIterPairIterator __seqs_begin,
|
|
_RAIterPairIterator __seqs_end,
|
|
_RAIterOut __target,
|
|
_DifferenceTp __length, _Compare __comp,
|
|
parallel_tag __tag = parallel_tag(0))
|
|
{ return multiway_merge(__seqs_begin, __seqs_end, __target, __length,
|
|
__comp, exact_tag(__tag.__get_num_threads())); }
|
|
|
|
// public interface
|
|
template<typename _RAIterPairIterator,
|
|
typename _RAIterOut,
|
|
typename _DifferenceTp,
|
|
typename _Compare>
|
|
_RAIterOut
|
|
multiway_merge(_RAIterPairIterator __seqs_begin,
|
|
_RAIterPairIterator __seqs_end,
|
|
_RAIterOut __target,
|
|
_DifferenceTp __length, _Compare __comp,
|
|
default_parallel_tag __tag)
|
|
{ return multiway_merge(__seqs_begin, __seqs_end, __target, __length,
|
|
__comp, exact_tag(__tag.__get_num_threads())); }
|
|
|
|
// stable_multiway_merge
|
|
// public interface
|
|
template<typename _RAIterPairIterator,
|
|
typename _RAIterOut,
|
|
typename _DifferenceTp,
|
|
typename _Compare>
|
|
_RAIterOut
|
|
stable_multiway_merge(_RAIterPairIterator __seqs_begin,
|
|
_RAIterPairIterator __seqs_end,
|
|
_RAIterOut __target,
|
|
_DifferenceTp __length, _Compare __comp,
|
|
__gnu_parallel::sequential_tag)
|
|
{
|
|
typedef _DifferenceTp _DifferenceType;
|
|
_GLIBCXX_CALL(__seqs_end - __seqs_begin)
|
|
|
|
// catch special case: no sequences
|
|
if (__seqs_begin == __seqs_end)
|
|
return __target;
|
|
|
|
// Execute multiway merge *sequentially*.
|
|
return __sequential_multiway_merge
|
|
</* __stable = */ true, /* __sentinels = */ false>
|
|
(__seqs_begin, __seqs_end, __target,
|
|
*(__seqs_begin->second), __length, __comp);
|
|
}
|
|
|
|
// public interface
|
|
template<typename _RAIterPairIterator,
|
|
typename _RAIterOut,
|
|
typename _DifferenceTp,
|
|
typename _Compare>
|
|
_RAIterOut
|
|
stable_multiway_merge(_RAIterPairIterator __seqs_begin,
|
|
_RAIterPairIterator __seqs_end,
|
|
_RAIterOut __target,
|
|
_DifferenceTp __length, _Compare __comp,
|
|
__gnu_parallel::exact_tag __tag)
|
|
{
|
|
typedef _DifferenceTp _DifferenceType;
|
|
_GLIBCXX_CALL(__seqs_end - __seqs_begin)
|
|
|
|
// catch special case: no sequences
|
|
if (__seqs_begin == __seqs_end)
|
|
return __target;
|
|
|
|
// Execute merge; maybe parallel, depending on the number of merged
|
|
// elements and the number of sequences and global thresholds in
|
|
// Settings.
|
|
if ((__seqs_end - __seqs_begin > 1)
|
|
&& _GLIBCXX_PARALLEL_CONDITION(
|
|
((__seqs_end - __seqs_begin) >=
|
|
__gnu_parallel::_Settings::get().multiway_merge_minimal_k)
|
|
&& ((_SequenceIndex)__length >=
|
|
__gnu_parallel::_Settings::get().multiway_merge_minimal_n)))
|
|
return parallel_multiway_merge
|
|
</* __stable = */ true, /* __sentinels = */ false>
|
|
(__seqs_begin, __seqs_end, __target,
|
|
multiway_merge_exact_splitting</* __stable = */ true,
|
|
typename std::iterator_traits<_RAIterPairIterator>
|
|
::value_type*, _Compare, _DifferenceTp>,
|
|
static_cast<_DifferenceType>(__length), __comp,
|
|
__tag.__get_num_threads());
|
|
else
|
|
return __sequential_multiway_merge
|
|
</* __stable = */ true, /* __sentinels = */ false>
|
|
(__seqs_begin, __seqs_end, __target,
|
|
*(__seqs_begin->second), __length, __comp);
|
|
}
|
|
|
|
// public interface
|
|
template<typename _RAIterPairIterator,
|
|
typename _RAIterOut,
|
|
typename _DifferenceTp,
|
|
typename _Compare>
|
|
_RAIterOut
|
|
stable_multiway_merge(_RAIterPairIterator __seqs_begin,
|
|
_RAIterPairIterator __seqs_end,
|
|
_RAIterOut __target,
|
|
_DifferenceTp __length, _Compare __comp,
|
|
sampling_tag __tag)
|
|
{
|
|
typedef _DifferenceTp _DifferenceType;
|
|
_GLIBCXX_CALL(__seqs_end - __seqs_begin)
|
|
|
|
// catch special case: no sequences
|
|
if (__seqs_begin == __seqs_end)
|
|
return __target;
|
|
|
|
// Execute merge; maybe parallel, depending on the number of merged
|
|
// elements and the number of sequences and global thresholds in
|
|
// Settings.
|
|
if ((__seqs_end - __seqs_begin > 1)
|
|
&& _GLIBCXX_PARALLEL_CONDITION(
|
|
((__seqs_end - __seqs_begin) >=
|
|
__gnu_parallel::_Settings::get().multiway_merge_minimal_k)
|
|
&& ((_SequenceIndex)__length >=
|
|
__gnu_parallel::_Settings::get().multiway_merge_minimal_n)))
|
|
return parallel_multiway_merge
|
|
</* __stable = */ true, /* __sentinels = */ false>
|
|
(__seqs_begin, __seqs_end, __target,
|
|
multiway_merge_sampling_splitting</* __stable = */ true,
|
|
typename std::iterator_traits<_RAIterPairIterator>
|
|
::value_type*, _Compare, _DifferenceTp>,
|
|
static_cast<_DifferenceType>(__length), __comp,
|
|
__tag.__get_num_threads());
|
|
else
|
|
return __sequential_multiway_merge
|
|
</* __stable = */ true, /* __sentinels = */ false>
|
|
(__seqs_begin, __seqs_end, __target,
|
|
*(__seqs_begin->second), __length, __comp);
|
|
}
|
|
|
|
// public interface
|
|
template<typename _RAIterPairIterator,
|
|
typename _RAIterOut,
|
|
typename _DifferenceTp,
|
|
typename _Compare>
|
|
_RAIterOut
|
|
stable_multiway_merge(_RAIterPairIterator __seqs_begin,
|
|
_RAIterPairIterator __seqs_end,
|
|
_RAIterOut __target,
|
|
_DifferenceTp __length, _Compare __comp,
|
|
parallel_tag __tag = parallel_tag(0))
|
|
{
|
|
return stable_multiway_merge
|
|
(__seqs_begin, __seqs_end, __target, __length, __comp,
|
|
exact_tag(__tag.__get_num_threads()));
|
|
}
|
|
|
|
// public interface
|
|
template<typename _RAIterPairIterator,
|
|
typename _RAIterOut,
|
|
typename _DifferenceTp,
|
|
typename _Compare>
|
|
_RAIterOut
|
|
stable_multiway_merge(_RAIterPairIterator __seqs_begin,
|
|
_RAIterPairIterator __seqs_end,
|
|
_RAIterOut __target,
|
|
_DifferenceTp __length, _Compare __comp,
|
|
default_parallel_tag __tag)
|
|
{
|
|
return stable_multiway_merge
|
|
(__seqs_begin, __seqs_end, __target, __length, __comp,
|
|
exact_tag(__tag.__get_num_threads()));
|
|
}
|
|
|
|
/**
|
|
* @brief Multiway Merge Frontend.
|
|
*
|
|
* Merge the sequences specified by seqs_begin and __seqs_end into
|
|
* __target. __seqs_begin and __seqs_end must point to a sequence of
|
|
* pairs. These pairs must contain an iterator to the beginning
|
|
* of a sequence in their first entry and an iterator the _M_end of
|
|
* the same sequence in their second entry.
|
|
*
|
|
* Ties are broken arbitrarily. See stable_multiway_merge for a variant
|
|
* that breaks ties by sequence number but is slower.
|
|
*
|
|
* The first entries of the pairs (i.e. the begin iterators) will be moved
|
|
* forward accordingly.
|
|
*
|
|
* The output sequence has to provide enough space for all elements
|
|
* that are written to it.
|
|
*
|
|
* This function will merge the input sequences:
|
|
*
|
|
* - not stable
|
|
* - parallel, depending on the input size and Settings
|
|
* - using sampling for splitting
|
|
* - using sentinels
|
|
*
|
|
* You have to take care that the element the _M_end iterator points to is
|
|
* readable and contains a value that is greater than any other non-sentinel
|
|
* value in all sequences.
|
|
*
|
|
* Example:
|
|
*
|
|
* <pre>
|
|
* int sequences[10][11];
|
|
* for (int __i = 0; __i < 10; ++__i)
|
|
* for (int __j = 0; __i < 11; ++__j)
|
|
* sequences[__i][__j] = __j; // __last one is sentinel!
|
|
*
|
|
* int __out[33];
|
|
* std::vector<std::pair<int*> > seqs;
|
|
* for (int __i = 0; __i < 10; ++__i)
|
|
* { seqs.push(std::make_pair<int*>(sequences[__i],
|
|
* sequences[__i] + 10)) }
|
|
*
|
|
* multiway_merge(seqs.begin(), seqs.end(), __target, std::less<int>(), 33);
|
|
* </pre>
|
|
*
|
|
* @pre All input sequences must be sorted.
|
|
* @pre Target must provide enough space to merge out length elements or
|
|
* the number of elements in all sequences, whichever is smaller.
|
|
* @pre For each @c __i, @c __seqs_begin[__i].second must be the end
|
|
* marker of the sequence, but also reference the one more __sentinel
|
|
* element.
|
|
*
|
|
* @post [__target, return __value) contains merged __elements from the
|
|
* input sequences.
|
|
* @post return __value - __target = min(__length, number of elements in all
|
|
* sequences).
|
|
*
|
|
* @see stable_multiway_merge_sentinels
|
|
*
|
|
* @param _RAIterPairIterator iterator over sequence
|
|
* of pairs of iterators
|
|
* @param _RAIterOut iterator over target sequence
|
|
* @param _DifferenceTp difference type for the sequence
|
|
* @param _Compare strict weak ordering type to compare elements
|
|
* in sequences
|
|
*
|
|
* @param __seqs_begin __begin of sequence __sequence
|
|
* @param __seqs_end _M_end of sequence __sequence
|
|
* @param __target target sequence to merge to.
|
|
* @param __comp strict weak ordering to use for element comparison.
|
|
* @param __length Maximum length to merge, possibly larger than the
|
|
* number of elements available.
|
|
*
|
|
* @return _M_end iterator of output sequence
|
|
*/
|
|
// multiway_merge_sentinels
|
|
// public interface
|
|
template<typename _RAIterPairIterator,
|
|
typename _RAIterOut,
|
|
typename _DifferenceTp,
|
|
typename _Compare>
|
|
_RAIterOut
|
|
multiway_merge_sentinels(_RAIterPairIterator __seqs_begin,
|
|
_RAIterPairIterator __seqs_end,
|
|
_RAIterOut __target,
|
|
_DifferenceTp __length, _Compare __comp,
|
|
__gnu_parallel::sequential_tag)
|
|
{
|
|
typedef _DifferenceTp _DifferenceType;
|
|
_GLIBCXX_CALL(__seqs_end - __seqs_begin)
|
|
|
|
// catch special case: no sequences
|
|
if (__seqs_begin == __seqs_end)
|
|
return __target;
|
|
|
|
// Execute multiway merge *sequentially*.
|
|
return __sequential_multiway_merge
|
|
</* __stable = */ false, /* __sentinels = */ true>
|
|
(__seqs_begin, __seqs_end,
|
|
__target, *(__seqs_begin->second), __length, __comp);
|
|
}
|
|
|
|
// public interface
|
|
template<typename _RAIterPairIterator,
|
|
typename _RAIterOut,
|
|
typename _DifferenceTp,
|
|
typename _Compare>
|
|
_RAIterOut
|
|
multiway_merge_sentinels(_RAIterPairIterator __seqs_begin,
|
|
_RAIterPairIterator __seqs_end,
|
|
_RAIterOut __target,
|
|
_DifferenceTp __length, _Compare __comp,
|
|
__gnu_parallel::exact_tag __tag)
|
|
{
|
|
typedef _DifferenceTp _DifferenceType;
|
|
_GLIBCXX_CALL(__seqs_end - __seqs_begin)
|
|
|
|
// catch special case: no sequences
|
|
if (__seqs_begin == __seqs_end)
|
|
return __target;
|
|
|
|
// Execute merge; maybe parallel, depending on the number of merged
|
|
// elements and the number of sequences and global thresholds in
|
|
// Settings.
|
|
if ((__seqs_end - __seqs_begin > 1)
|
|
&& _GLIBCXX_PARALLEL_CONDITION(
|
|
((__seqs_end - __seqs_begin) >=
|
|
__gnu_parallel::_Settings::get().multiway_merge_minimal_k)
|
|
&& ((_SequenceIndex)__length >=
|
|
__gnu_parallel::_Settings::get().multiway_merge_minimal_n)))
|
|
return parallel_multiway_merge
|
|
</* __stable = */ false, /* __sentinels = */ true>
|
|
(__seqs_begin, __seqs_end, __target,
|
|
multiway_merge_exact_splitting</* __stable = */ false,
|
|
typename std::iterator_traits<_RAIterPairIterator>
|
|
::value_type*, _Compare, _DifferenceTp>,
|
|
static_cast<_DifferenceType>(__length), __comp,
|
|
__tag.__get_num_threads());
|
|
else
|
|
return __sequential_multiway_merge
|
|
</* __stable = */ false, /* __sentinels = */ true>
|
|
(__seqs_begin, __seqs_end, __target,
|
|
*(__seqs_begin->second), __length, __comp);
|
|
}
|
|
|
|
// public interface
|
|
template<typename _RAIterPairIterator,
|
|
typename _RAIterOut,
|
|
typename _DifferenceTp,
|
|
typename _Compare>
|
|
_RAIterOut
|
|
multiway_merge_sentinels(_RAIterPairIterator __seqs_begin,
|
|
_RAIterPairIterator __seqs_end,
|
|
_RAIterOut __target,
|
|
_DifferenceTp __length, _Compare __comp,
|
|
sampling_tag __tag)
|
|
{
|
|
typedef _DifferenceTp _DifferenceType;
|
|
_GLIBCXX_CALL(__seqs_end - __seqs_begin)
|
|
|
|
// catch special case: no sequences
|
|
if (__seqs_begin == __seqs_end)
|
|
return __target;
|
|
|
|
// Execute merge; maybe parallel, depending on the number of merged
|
|
// elements and the number of sequences and global thresholds in
|
|
// Settings.
|
|
if ((__seqs_end - __seqs_begin > 1)
|
|
&& _GLIBCXX_PARALLEL_CONDITION(
|
|
((__seqs_end - __seqs_begin) >=
|
|
__gnu_parallel::_Settings::get().multiway_merge_minimal_k)
|
|
&& ((_SequenceIndex)__length >=
|
|
__gnu_parallel::_Settings::get().multiway_merge_minimal_n)))
|
|
return parallel_multiway_merge
|
|
</* __stable = */ false, /* __sentinels = */ true>
|
|
(__seqs_begin, __seqs_end, __target,
|
|
multiway_merge_sampling_splitting</* __stable = */ false,
|
|
typename std::iterator_traits<_RAIterPairIterator>
|
|
::value_type*, _Compare, _DifferenceTp>,
|
|
static_cast<_DifferenceType>(__length), __comp,
|
|
__tag.__get_num_threads());
|
|
else
|
|
return __sequential_multiway_merge
|
|
</* __stable = */false, /* __sentinels = */ true>(
|
|
__seqs_begin, __seqs_end, __target,
|
|
*(__seqs_begin->second), __length, __comp);
|
|
}
|
|
|
|
// public interface
|
|
template<typename _RAIterPairIterator,
|
|
typename _RAIterOut,
|
|
typename _DifferenceTp,
|
|
typename _Compare>
|
|
_RAIterOut
|
|
multiway_merge_sentinels(_RAIterPairIterator __seqs_begin,
|
|
_RAIterPairIterator __seqs_end,
|
|
_RAIterOut __target,
|
|
_DifferenceTp __length, _Compare __comp,
|
|
parallel_tag __tag = parallel_tag(0))
|
|
{
|
|
return multiway_merge_sentinels
|
|
(__seqs_begin, __seqs_end, __target, __length, __comp,
|
|
exact_tag(__tag.__get_num_threads()));
|
|
}
|
|
|
|
// public interface
|
|
template<typename _RAIterPairIterator,
|
|
typename _RAIterOut,
|
|
typename _DifferenceTp,
|
|
typename _Compare>
|
|
_RAIterOut
|
|
multiway_merge_sentinels(_RAIterPairIterator __seqs_begin,
|
|
_RAIterPairIterator __seqs_end,
|
|
_RAIterOut __target,
|
|
_DifferenceTp __length, _Compare __comp,
|
|
default_parallel_tag __tag)
|
|
{
|
|
return multiway_merge_sentinels
|
|
(__seqs_begin, __seqs_end, __target, __length, __comp,
|
|
exact_tag(__tag.__get_num_threads()));
|
|
}
|
|
|
|
// stable_multiway_merge_sentinels
|
|
// public interface
|
|
template<typename _RAIterPairIterator,
|
|
typename _RAIterOut,
|
|
typename _DifferenceTp,
|
|
typename _Compare>
|
|
_RAIterOut
|
|
stable_multiway_merge_sentinels(_RAIterPairIterator __seqs_begin,
|
|
_RAIterPairIterator __seqs_end,
|
|
_RAIterOut __target,
|
|
_DifferenceTp __length, _Compare __comp,
|
|
__gnu_parallel::sequential_tag)
|
|
{
|
|
typedef _DifferenceTp _DifferenceType;
|
|
_GLIBCXX_CALL(__seqs_end - __seqs_begin)
|
|
|
|
// catch special case: no sequences
|
|
if (__seqs_begin == __seqs_end)
|
|
return __target;
|
|
|
|
// Execute multiway merge *sequentially*.
|
|
return __sequential_multiway_merge
|
|
</* __stable = */ true, /* __sentinels = */ true>
|
|
(__seqs_begin, __seqs_end, __target,
|
|
*(__seqs_begin->second), __length, __comp);
|
|
}
|
|
|
|
// public interface
|
|
template<typename _RAIterPairIterator,
|
|
typename _RAIterOut,
|
|
typename _DifferenceTp,
|
|
typename _Compare>
|
|
_RAIterOut
|
|
stable_multiway_merge_sentinels(_RAIterPairIterator __seqs_begin,
|
|
_RAIterPairIterator __seqs_end,
|
|
_RAIterOut __target,
|
|
_DifferenceTp __length, _Compare __comp,
|
|
__gnu_parallel::exact_tag __tag)
|
|
{
|
|
typedef _DifferenceTp _DifferenceType;
|
|
_GLIBCXX_CALL(__seqs_end - __seqs_begin)
|
|
|
|
// catch special case: no sequences
|
|
if (__seqs_begin == __seqs_end)
|
|
return __target;
|
|
|
|
// Execute merge; maybe parallel, depending on the number of merged
|
|
// elements and the number of sequences and global thresholds in
|
|
// Settings.
|
|
if ((__seqs_end - __seqs_begin > 1)
|
|
&& _GLIBCXX_PARALLEL_CONDITION(
|
|
((__seqs_end - __seqs_begin) >=
|
|
__gnu_parallel::_Settings::get().multiway_merge_minimal_k)
|
|
&& ((_SequenceIndex)__length >=
|
|
__gnu_parallel::_Settings::get().multiway_merge_minimal_n)))
|
|
return parallel_multiway_merge
|
|
</* __stable = */ true, /* __sentinels = */ true>
|
|
(__seqs_begin, __seqs_end, __target,
|
|
multiway_merge_exact_splitting</* __stable = */ true,
|
|
typename std::iterator_traits<_RAIterPairIterator>
|
|
::value_type*, _Compare, _DifferenceTp>,
|
|
static_cast<_DifferenceType>(__length), __comp,
|
|
__tag.__get_num_threads());
|
|
else
|
|
return __sequential_multiway_merge
|
|
</* __stable = */ true, /* __sentinels = */ true>
|
|
(__seqs_begin, __seqs_end, __target,
|
|
*(__seqs_begin->second), __length, __comp);
|
|
}
|
|
|
|
// public interface
|
|
template<typename _RAIterPairIterator,
|
|
typename _RAIterOut,
|
|
typename _DifferenceTp,
|
|
typename _Compare>
|
|
_RAIterOut
|
|
stable_multiway_merge_sentinels(_RAIterPairIterator __seqs_begin,
|
|
_RAIterPairIterator __seqs_end,
|
|
_RAIterOut __target,
|
|
_DifferenceTp __length,
|
|
_Compare __comp,
|
|
sampling_tag __tag)
|
|
{
|
|
typedef _DifferenceTp _DifferenceType;
|
|
_GLIBCXX_CALL(__seqs_end - __seqs_begin)
|
|
|
|
// catch special case: no sequences
|
|
if (__seqs_begin == __seqs_end)
|
|
return __target;
|
|
|
|
// Execute merge; maybe parallel, depending on the number of merged
|
|
// elements and the number of sequences and global thresholds in
|
|
// Settings.
|
|
if ((__seqs_end - __seqs_begin > 1)
|
|
&& _GLIBCXX_PARALLEL_CONDITION(
|
|
((__seqs_end - __seqs_begin) >=
|
|
__gnu_parallel::_Settings::get().multiway_merge_minimal_k)
|
|
&& ((_SequenceIndex)__length >=
|
|
__gnu_parallel::_Settings::get().multiway_merge_minimal_n)))
|
|
return parallel_multiway_merge
|
|
</* __stable = */ true, /* __sentinels = */ true>
|
|
(__seqs_begin, __seqs_end, __target,
|
|
multiway_merge_sampling_splitting</* __stable = */ true,
|
|
typename std::iterator_traits<_RAIterPairIterator>
|
|
::value_type*, _Compare, _DifferenceTp>,
|
|
static_cast<_DifferenceType>(__length), __comp,
|
|
__tag.__get_num_threads());
|
|
else
|
|
return __sequential_multiway_merge
|
|
</* __stable = */ true, /* __sentinels = */ true>
|
|
(__seqs_begin, __seqs_end, __target,
|
|
*(__seqs_begin->second), __length, __comp);
|
|
}
|
|
|
|
// public interface
|
|
template<typename _RAIterPairIterator,
|
|
typename _RAIterOut,
|
|
typename _DifferenceTp,
|
|
typename _Compare>
|
|
_RAIterOut
|
|
stable_multiway_merge_sentinels(_RAIterPairIterator __seqs_begin,
|
|
_RAIterPairIterator __seqs_end,
|
|
_RAIterOut __target,
|
|
_DifferenceTp __length,
|
|
_Compare __comp,
|
|
parallel_tag __tag = parallel_tag(0))
|
|
{
|
|
return stable_multiway_merge_sentinels
|
|
(__seqs_begin, __seqs_end, __target, __length, __comp,
|
|
exact_tag(__tag.__get_num_threads()));
|
|
}
|
|
|
|
// public interface
|
|
template<typename _RAIterPairIterator,
|
|
typename _RAIterOut,
|
|
typename _DifferenceTp,
|
|
typename _Compare>
|
|
_RAIterOut
|
|
stable_multiway_merge_sentinels(_RAIterPairIterator __seqs_begin,
|
|
_RAIterPairIterator __seqs_end,
|
|
_RAIterOut __target,
|
|
_DifferenceTp __length, _Compare __comp,
|
|
default_parallel_tag __tag)
|
|
{
|
|
return stable_multiway_merge_sentinels
|
|
(__seqs_begin, __seqs_end, __target, __length, __comp,
|
|
exact_tag(__tag.__get_num_threads()));
|
|
}
|
|
}; // namespace __gnu_parallel
|
|
|
|
#endif /* _GLIBCXX_PARALLEL_MULTIWAY_MERGE_H */
|