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//usr/include/c++/8/parallel/unique_copy.h

// -*- C++ -*-

// Copyright (C) 2007-2018 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/unique_copy.h
 *  @brief Parallel implementations of std::unique_copy().
 *  This file is a GNU parallel extension to the Standard C++ Library.
 */

// Written by Robert Geisberger and Robin Dapp.

#ifndef _GLIBCXX_PARALLEL_UNIQUE_COPY_H
#define _GLIBCXX_PARALLEL_UNIQUE_COPY_H 1

#include <parallel/parallel.h>
#include <parallel/multiseq_selection.h>

namespace __gnu_parallel
{
  /** @brief Parallel std::unique_copy(), w/__o explicit equality predicate.
    *  @param __first Begin iterator of input sequence.
    *  @param __last End iterator of input sequence.
    *  @param __result Begin iterator of result __sequence.
    *  @param __binary_pred Equality predicate.
    *  @return End iterator of result __sequence. */
  template<typename _IIter,
           class _OutputIterator,
           class _BinaryPredicate>
    _OutputIterator
    __parallel_unique_copy(_IIter __first, _IIter __last,
			   _OutputIterator __result,
			   _BinaryPredicate __binary_pred)
    {
      _GLIBCXX_CALL(__last - __first)

      typedef std::iterator_traits<_IIter> _TraitsType;
      typedef typename _TraitsType::value_type _ValueType;
      typedef typename _TraitsType::difference_type _DifferenceType;

      _DifferenceType __size = __last - __first;

      if (__size == 0)
	return __result;

      // Let the first thread process two parts.
      _DifferenceType *__counter;
      _DifferenceType *__borders;

      _ThreadIndex __num_threads = __get_max_threads();
      // First part contains at least one element.
#     pragma omp parallel num_threads(__num_threads)
      {
#       pragma omp single
	{
	  __num_threads = omp_get_num_threads();
	  __borders = new _DifferenceType[__num_threads + 2];
	  __equally_split(__size, __num_threads + 1, __borders);
	  __counter = new _DifferenceType[__num_threads + 1];
	}

	_ThreadIndex __iam = omp_get_thread_num();

	_DifferenceType __begin, __end;

	// Check for length without duplicates
	// Needed for position in output
	_DifferenceType __i = 0;
	_OutputIterator __out = __result;

	if (__iam == 0)
          {
            __begin = __borders[0] + 1;   // == 1
            __end = __borders[__iam + 1];

            ++__i;
            *__out++ = *__first;

            for (_IIter __iter = __first + __begin; __iter < __first + __end;
		 ++__iter)
              {
        	if (!__binary_pred(*__iter, *(__iter - 1)))
                  {
                    ++__i;
                    *__out++ = *__iter;
                  }
              }
          }
	else
          {
            __begin = __borders[__iam]; //one part
            __end = __borders[__iam + 1];

            for (_IIter __iter = __first + __begin; __iter < __first + __end;
		 ++__iter)
              {
        	if (!__binary_pred(*__iter, *(__iter - 1)))
                  ++__i;
              }
          }
	__counter[__iam] = __i;

	// Last part still untouched.
	_DifferenceType __begin_output;

#       pragma omp barrier

	// Store result in output on calculated positions.
	__begin_output = 0;

	if (__iam == 0)
          {
            for (_ThreadIndex __t = 0; __t < __num_threads; ++__t)
              __begin_output += __counter[__t];

            __i = 0;

            _OutputIterator __iter_out = __result + __begin_output;

            __begin = __borders[__num_threads];
            __end = __size;

            for (_IIter __iter = __first + __begin; __iter < __first + __end;
		 ++__iter)
              {
        	if (__iter == __first
		    || !__binary_pred(*__iter, *(__iter - 1)))
                  {
                    ++__i;
                    *__iter_out++ = *__iter;
                  }
              }

            __counter[__num_threads] = __i;
          }
	else
          {
            for (_ThreadIndex __t = 0; __t < __iam; __t++)
              __begin_output += __counter[__t];

            _OutputIterator __iter_out = __result + __begin_output;
            for (_IIter __iter = __first + __begin; __iter < __first + __end;
		 ++__iter)
              {
        	if (!__binary_pred(*__iter, *(__iter - 1)))
                  *__iter_out++ = *__iter;
              }
          }
      }

      _DifferenceType __end_output = 0;
      for (_ThreadIndex __t = 0; __t < __num_threads + 1; __t++)
	__end_output += __counter[__t];

      delete[] __borders;

      return __result + __end_output;
    }

  /** @brief Parallel std::unique_copy(), without explicit equality predicate
    *  @param __first Begin iterator of input sequence.
    *  @param __last End iterator of input sequence.
    *  @param __result Begin iterator of result __sequence.
    *  @return End iterator of result __sequence. */
  template<typename _IIter, class _OutputIterator>
    inline _OutputIterator
    __parallel_unique_copy(_IIter __first, _IIter __last,
			   _OutputIterator __result)
    {
      typedef typename std::iterator_traits<_IIter>::value_type
	_ValueType;
      return __parallel_unique_copy(__first, __last, __result,
				    std::equal_to<_ValueType>());
    }

}//namespace __gnu_parallel

#endif /* _GLIBCXX_PARALLEL_UNIQUE_COPY_H */

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algo.h	78.15 KB	lrw-r--r--	2025-08-26 09:45:05	Edit Download recursive recursive
algobase.h	16.75 KB	lrw-r--r--	2025-08-26 09:45:05	Edit Download recursive recursive
algorithm	1.35 KB	lrw-r--r--	2025-08-26 09:45:05	Edit Download recursive recursive
algorithmfwd.h	31.45 KB	lrw-r--r--	2025-08-26 09:45:05	Edit Download recursive recursive
balanced_quicksort.h	16.55 KB	lrw-r--r--	2025-08-26 09:45:05	Edit Download recursive recursive
base.h	12.08 KB	lrw-r--r--	2025-08-26 09:45:05	Edit Download recursive recursive
basic_iterator.h	1.55 KB	lrw-r--r--	2025-08-26 09:45:05	Edit Download recursive recursive
checkers.h	2.25 KB	lrw-r--r--	2025-08-26 09:45:05	Edit Download recursive recursive
compatibility.h	3.70 KB	lrw-r--r--	2025-08-26 09:45:05	Edit Download recursive recursive
compiletime_settings.h	2.80 KB	lrw-r--r--	2025-08-26 09:45:05	Edit Download recursive recursive
equally_split.h	3.28 KB	lrw-r--r--	2025-08-26 09:45:05	Edit Download recursive recursive
features.h	3.46 KB	lrw-r--r--	2025-08-26 09:45:05	Edit Download recursive recursive
find.h	13.27 KB	lrw-r--r--	2025-08-26 09:45:05	Edit Download recursive recursive
find_selectors.h	6.83 KB	lrw-r--r--	2025-08-26 09:45:05	Edit Download recursive recursive
for_each.h	3.85 KB	lrw-r--r--	2025-08-26 09:45:05	Edit Download recursive recursive
for_each_selectors.h	10.32 KB	lrw-r--r--	2025-08-26 09:45:05	Edit Download recursive recursive
iterator.h	5.54 KB	lrw-r--r--	2025-08-26 09:45:05	Edit Download recursive recursive
list_partition.h	6.39 KB	lrw-r--r--	2025-08-26 09:45:05	Edit Download recursive recursive
losertree.h	27.92 KB	lrw-r--r--	2025-08-26 09:45:05	Edit Download recursive recursive
merge.h	9.35 KB	lrw-r--r--	2025-08-26 09:45:05	Edit Download recursive recursive
multiseq_selection.h	21.56 KB	lrw-r--r--	2025-08-26 09:45:05	Edit Download recursive recursive
multiway_merge.h	68.88 KB	lrw-r--r--	2025-08-26 09:45:05	Edit Download recursive recursive
multiway_mergesort.h	14.91 KB	lrw-r--r--	2025-08-26 09:45:05	Edit Download recursive recursive
numeric	20.23 KB	lrw-r--r--	2025-08-26 09:45:05	Edit Download recursive recursive
numericfwd.h	7.32 KB	lrw-r--r--	2025-08-26 09:45:05	Edit Download recursive recursive
omp_loop.h	3.94 KB	lrw-r--r--	2025-08-26 09:45:05	Edit Download recursive recursive
omp_loop_static.h	4.01 KB	lrw-r--r--	2025-08-26 09:45:05	Edit Download recursive recursive
parallel.h	1.54 KB	lrw-r--r--	2025-08-26 09:45:05	Edit Download recursive recursive
partial_sum.h	7.30 KB	lrw-r--r--	2025-08-26 09:45:05	Edit Download recursive recursive
partition.h	14.61 KB	lrw-r--r--	2025-08-26 09:45:05	Edit Download recursive recursive
par_loop.h	4.45 KB	lrw-r--r--	2025-08-26 09:45:05	Edit Download recursive recursive
queue.h	5.41 KB	lrw-r--r--	2025-08-26 09:45:05	Edit Download recursive recursive
quicksort.h	5.98 KB	lrw-r--r--	2025-08-26 09:45:05	Edit Download recursive recursive
random_number.h	4.13 KB	lrw-r--r--	2025-08-26 09:45:05	Edit Download recursive recursive
random_shuffle.h	18.24 KB	lrw-r--r--	2025-08-26 09:45:05	Edit Download recursive recursive
search.h	5.26 KB	lrw-r--r--	2025-08-26 09:45:05	Edit Download recursive recursive
settings.h	12.17 KB	lrw-r--r--	2025-08-26 09:45:05	Edit Download recursive recursive
set_operations.h	14.25 KB	lrw-r--r--	2025-08-26 09:45:05	Edit Download recursive recursive
sort.h	7.53 KB	lrw-r--r--	2025-08-26 09:45:05	Edit Download recursive recursive
tags.h	5.84 KB	lrw-r--r--	2025-08-26 09:45:05	Edit Download recursive recursive
types.h	3.63 KB	lrw-r--r--	2025-08-26 09:45:05	Edit Download recursive recursive
unique_copy.h	6.02 KB	lrw-r--r--	2025-08-26 09:45:05	Edit Download recursive recursive
workstealing.h	9.39 KB	lrw-r--r--	2025-08-26 09:45:05	Edit Download recursive recursive