--- /dev/null
+// -*- C++ -*-
+
+// Copyright (C) 2007, 2008, 2009 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library. This library is free
+// software; you can redistribute it and/or modify it under the terms
+// of the GNU General Public License as published by the Free Software
+// Foundation; either version 3, or (at your option) any later
+// version.
+
+// This library is distributed in the hope that it will be useful, but
+// WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+// General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
+// <http://www.gnu.org/licenses/>.
+
+/**
+ * @file parallel/set_operations.h
+ * @brief Parallel implementations of set operations for random-access
+ * iterators.
+ * This file is a GNU parallel extension to the Standard C++ Library.
+ */
+
+// Written by Marius Elvert and Felix Bondarenko.
+
+#ifndef _GLIBCXX_PARALLEL_SET_OPERATIONS_H
+#define _GLIBCXX_PARALLEL_SET_OPERATIONS_H 1
+
+#include <omp.h>
+
+#include <parallel/settings.h>
+#include <parallel/multiseq_selection.h>
+
+namespace __gnu_parallel
+{
+template<typename InputIterator, typename OutputIterator>
+ OutputIterator
+ copy_tail(std::pair<InputIterator, InputIterator> b,
+ std::pair<InputIterator, InputIterator> e, OutputIterator r)
+ {
+ if (b.first != e.first)
+ {
+ do
+ {
+ *r++ = *b.first++;
+ }
+ while (b.first != e.first);
+ }
+ else
+ {
+ while (b.second != e.second)
+ *r++ = *b.second++;
+ }
+ return r;
+ }
+
+template<typename InputIterator,
+ typename OutputIterator,
+ typename Comparator>
+ struct symmetric_difference_func
+ {
+ typedef std::iterator_traits<InputIterator> traits_type;
+ typedef typename traits_type::difference_type difference_type;
+ typedef typename std::pair<InputIterator, InputIterator> iterator_pair;
+
+ symmetric_difference_func(Comparator c) : comp(c) {}
+
+ Comparator comp;
+
+ OutputIterator
+ invoke(InputIterator a, InputIterator b,
+ InputIterator c, InputIterator d,
+ OutputIterator r) const
+ {
+ while (a != b && c != d)
+ {
+ if (comp(*a, *c))
+ {
+ *r = *a;
+ ++a;
+ ++r;
+ }
+ else if (comp(*c, *a))
+ {
+ *r = *c;
+ ++c;
+ ++r;
+ }
+ else
+ {
+ ++a;
+ ++c;
+ }
+ }
+ return std::copy(c, d, std::copy(a, b, r));
+ }
+
+ difference_type
+ count(InputIterator a, InputIterator b,
+ InputIterator c, InputIterator d) const
+ {
+ difference_type counter = 0;
+
+ while (a != b && c != d)
+ {
+ if (comp(*a, *c))
+ {
+ ++a;
+ ++counter;
+ }
+ else if (comp(*c, *a))
+ {
+ ++c;
+ ++counter;
+ }
+ else
+ {
+ ++a;
+ ++c;
+ }
+ }
+
+ return counter + (b - a) + (d - c);
+ }
+
+ OutputIterator
+ first_empty(InputIterator c, InputIterator d, OutputIterator out) const
+ { return std::copy(c, d, out); }
+
+ OutputIterator
+ second_empty(InputIterator a, InputIterator b, OutputIterator out) const
+ { return std::copy(a, b, out); }
+ };
+
+
+template<typename InputIterator,
+ typename OutputIterator,
+ typename Comparator>
+ struct difference_func
+ {
+ typedef std::iterator_traits<InputIterator> traits_type;
+ typedef typename traits_type::difference_type difference_type;
+ typedef typename std::pair<InputIterator, InputIterator> iterator_pair;
+
+ difference_func(Comparator c) : comp(c) {}
+
+ Comparator comp;
+
+ OutputIterator
+ invoke(InputIterator a, InputIterator b, InputIterator c, InputIterator d,
+ OutputIterator r) const
+ {
+ while (a != b && c != d)
+ {
+ if (comp(*a, *c))
+ {
+ *r = *a;
+ ++a;
+ ++r;
+ }
+ else if (comp(*c, *a))
+ { ++c; }
+ else
+ {
+ ++a;
+ ++c;
+ }
+ }
+ return std::copy(a, b, r);
+ }
+
+ difference_type
+ count(InputIterator a, InputIterator b,
+ InputIterator c, InputIterator d) const
+ {
+ difference_type counter = 0;
+
+ while (a != b && c != d)
+ {
+ if (comp(*a, *c))
+ {
+ ++a;
+ ++counter;
+ }
+ else if (comp(*c, *a))
+ { ++c; }
+ else
+ { ++a; ++c; }
+ }
+
+ return counter + (b - a);
+ }
+
+ inline OutputIterator
+ first_empty(InputIterator c, InputIterator d, OutputIterator out) const
+ { return out; }
+
+ inline OutputIterator
+ second_empty(InputIterator a, InputIterator b, OutputIterator out) const
+ { return std::copy(a, b, out); }
+ };
+
+
+template<typename InputIterator,
+ typename OutputIterator,
+ typename Comparator>
+ struct intersection_func
+ {
+ typedef std::iterator_traits<InputIterator> traits_type;
+ typedef typename traits_type::difference_type difference_type;
+ typedef typename std::pair<InputIterator, InputIterator> iterator_pair;
+
+ intersection_func(Comparator c) : comp(c) {}
+
+ Comparator comp;
+
+ OutputIterator
+ invoke(InputIterator a, InputIterator b, InputIterator c, InputIterator d,
+ OutputIterator r) const
+ {
+ while (a != b && c != d)
+ {
+ if (comp(*a, *c))
+ { ++a; }
+ else if (comp(*c, *a))
+ { ++c; }
+ else
+ {
+ *r = *a;
+ ++a;
+ ++c;
+ ++r;
+ }
+ }
+
+ return r;
+ }
+
+ difference_type
+ count(InputIterator a, InputIterator b,
+ InputIterator c, InputIterator d) const
+ {
+ difference_type counter = 0;
+
+ while (a != b && c != d)
+ {
+ if (comp(*a, *c))
+ { ++a; }
+ else if (comp(*c, *a))
+ { ++c; }
+ else
+ {
+ ++a;
+ ++c;
+ ++counter;
+ }
+ }
+
+ return counter;
+ }
+
+ inline OutputIterator
+ first_empty(InputIterator c, InputIterator d, OutputIterator out) const
+ { return out; }
+
+ inline OutputIterator
+ second_empty(InputIterator a, InputIterator b, OutputIterator out) const
+ { return out; }
+ };
+
+template<class InputIterator, class OutputIterator, class Comparator>
+ struct union_func
+ {
+ typedef typename std::iterator_traits<InputIterator>::difference_type
+ difference_type;
+
+ union_func(Comparator c) : comp(c) {}
+
+ Comparator comp;
+
+ OutputIterator
+ invoke(InputIterator a, const InputIterator b, InputIterator c,
+ const InputIterator d, OutputIterator r) const
+ {
+ while (a != b && c != d)
+ {
+ if (comp(*a, *c))
+ {
+ *r = *a;
+ ++a;
+ }
+ else if (comp(*c, *a))
+ {
+ *r = *c;
+ ++c;
+ }
+ else
+ {
+ *r = *a;
+ ++a;
+ ++c;
+ }
+ ++r;
+ }
+ return std::copy(c, d, std::copy(a, b, r));
+ }
+
+ difference_type
+ count(InputIterator a, InputIterator b,
+ InputIterator c, InputIterator d) const
+ {
+ difference_type counter = 0;
+
+ while (a != b && c != d)
+ {
+ if (comp(*a, *c))
+ { ++a; }
+ else if (comp(*c, *a))
+ { ++c; }
+ else
+ {
+ ++a;
+ ++c;
+ }
+ ++counter;
+ }
+
+ counter += (b - a);
+ counter += (d - c);
+ return counter;
+ }
+
+ inline OutputIterator
+ first_empty(InputIterator c, InputIterator d, OutputIterator out) const
+ { return std::copy(c, d, out); }
+
+ inline OutputIterator
+ second_empty(InputIterator a, InputIterator b, OutputIterator out) const
+ { return std::copy(a, b, out); }
+ };
+
+template<typename InputIterator,
+ typename OutputIterator,
+ typename Operation>
+ OutputIterator
+ parallel_set_operation(InputIterator begin1, InputIterator end1,
+ InputIterator begin2, InputIterator end2,
+ OutputIterator result, Operation op)
+ {
+ _GLIBCXX_CALL((end1 - begin1) + (end2 - begin2))
+
+ typedef std::iterator_traits<InputIterator> traits_type;
+ typedef typename traits_type::difference_type difference_type;
+ typedef typename std::pair<InputIterator, InputIterator> iterator_pair;
+
+ if (begin1 == end1)
+ return op.first_empty(begin2, end2, result);
+
+ if (begin2 == end2)
+ return op.second_empty(begin1, end1, result);
+
+ const difference_type size = (end1 - begin1) + (end2 - begin2);
+
+ const iterator_pair sequence[ 2 ] =
+ { std::make_pair(begin1, end1), std::make_pair(begin2, end2) } ;
+ OutputIterator return_value = result;
+ difference_type *borders;
+ iterator_pair *block_begins;
+ difference_type* lengths;
+
+ thread_index_t num_threads =
+ std::min<difference_type>(get_max_threads(),
+ std::min(end1 - begin1, end2 - begin2));
+
+# pragma omp parallel num_threads(num_threads)
+ {
+# pragma omp single
+ {
+ num_threads = omp_get_num_threads();
+
+ borders = new difference_type[num_threads + 2];
+ equally_split(size, num_threads + 1, borders);
+ block_begins = new iterator_pair[num_threads + 1];
+ // Very start.
+ block_begins[0] = std::make_pair(begin1, begin2);
+ lengths = new difference_type[num_threads];
+ } //single
+
+ thread_index_t iam = omp_get_thread_num();
+
+ // Result from multiseq_partition.
+ InputIterator offset[2];
+ const difference_type rank = borders[iam + 1];
+
+ multiseq_partition(sequence, sequence + 2, rank, offset, op.comp);
+
+ // allowed to read?
+ // together
+ // *(offset[ 0 ] - 1) == *offset[ 1 ]
+ if (offset[ 0 ] != begin1 && offset[ 1 ] != end2
+ && !op.comp(*(offset[ 0 ] - 1), *offset[ 1 ])
+ && !op.comp(*offset[ 1 ], *(offset[ 0 ] - 1)))
+ {
+ // Avoid split between globally equal elements: move one to
+ // front in first sequence.
+ --offset[ 0 ];
+ }
+
+ iterator_pair block_end = block_begins[ iam + 1 ] =
+ iterator_pair(offset[ 0 ], offset[ 1 ]);
+
+ // Make sure all threads have their block_begin result written out.
+# pragma omp barrier
+
+ iterator_pair block_begin = block_begins[ iam ];
+
+ // Begin working for the first block, while the others except
+ // the last start to count.
+ if (iam == 0)
+ {
+ // The first thread can copy already.
+ lengths[ iam ] = op.invoke(block_begin.first, block_end.first,
+ block_begin.second, block_end.second,
+ result)
+ - result;
+ }
+ else
+ {
+ lengths[ iam ] = op.count(block_begin.first, block_end.first,
+ block_begin.second, block_end.second);
+ }
+
+ // Make sure everyone wrote their lengths.
+# pragma omp barrier
+
+ OutputIterator r = result;
+
+ if (iam == 0)
+ {
+ // Do the last block.
+ for (int i = 0; i < num_threads; ++i)
+ r += lengths[i];
+
+ block_begin = block_begins[num_threads];
+
+ // Return the result iterator of the last block.
+ return_value = op.invoke(
+ block_begin.first, end1, block_begin.second, end2, r);
+
+ }
+ else
+ {
+ for (int i = 0; i < iam; ++i)
+ r += lengths[ i ];
+
+ // Reset begins for copy pass.
+ op.invoke(block_begin.first, block_end.first,
+ block_begin.second, block_end.second, r);
+ }
+ }
+ return return_value;
+ }
+
+
+template<typename InputIterator,
+ typename OutputIterator,
+ typename Comparator>
+ inline OutputIterator
+ parallel_set_union(InputIterator begin1, InputIterator end1,
+ InputIterator begin2, InputIterator end2,
+ OutputIterator result, Comparator comp)
+ {
+ return parallel_set_operation(begin1, end1, begin2, end2, result,
+ union_func< InputIterator, OutputIterator, Comparator>(comp));
+ }
+
+template<typename InputIterator,
+ typename OutputIterator,
+ typename Comparator>
+ inline OutputIterator
+ parallel_set_intersection(InputIterator begin1, InputIterator end1,
+ InputIterator begin2, InputIterator end2,
+ OutputIterator result, Comparator comp)
+ {
+ return parallel_set_operation(begin1, end1, begin2, end2, result,
+ intersection_func<InputIterator, OutputIterator, Comparator>(comp));
+ }
+
+template<typename InputIterator,
+ typename OutputIterator,
+ typename Comparator>
+ inline OutputIterator
+ parallel_set_difference(InputIterator begin1, InputIterator end1,
+ InputIterator begin2, InputIterator end2,
+ OutputIterator result, Comparator comp)
+ {
+ return parallel_set_operation(begin1, end1, begin2, end2, result,
+ difference_func<InputIterator, OutputIterator, Comparator>(comp));
+ }
+
+template<typename InputIterator,
+ typename OutputIterator,
+ typename Comparator>
+ inline OutputIterator
+ parallel_set_symmetric_difference(InputIterator begin1, InputIterator end1,
+ InputIterator begin2, InputIterator end2,
+ OutputIterator result, Comparator comp)
+ {
+ return parallel_set_operation(begin1, end1, begin2, end2, result,
+ symmetric_difference_func<InputIterator, OutputIterator, Comparator>
+ (comp));
+ }
+
+}
+
+#endif /* _GLIBCXX_PARALLEL_SET_OPERATIONS_H */
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