11.2.0/parallel/unique_copy.h

// -*- C++ -*-

// Copyright (C) 2007-2021 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 */
Revision:	1166
Committed:	Tue Oct 26 14:22:36 2021 UTC (4 years ago) by rossy
Content type:	text/x-chdr
File size:	6165 byte(s)
Log Message:	Daodan: Replace MinGW build env with an up-to-date MSYS2 env
#	Content
1	// -- C++ --
2
3	// Copyright (C) 2007-2021 Free Software Foundation, Inc.
4	//
5	// This file is part of the GNU ISO C++ Library. This library is free
6	// software; you can redistribute it and/or modify it under the terms
7	// of the GNU General Public License as published by the Free Software
8	// Foundation; either version 3, or (at your option) any later
9	// version.
10
11	// This library is distributed in the hope that it will be useful, but
12	// WITHOUT ANY WARRANTY; without even the implied warranty of
13	// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14	// General Public License for more details.
15
16	// Under Section 7 of GPL version 3, you are granted additional
17	// permissions described in the GCC Runtime Library Exception, version
18	// 3.1, as published by the Free Software Foundation.
19
20	// You should have received a copy of the GNU General Public License and
21	// a copy of the GCC Runtime Library Exception along with this program;
22	// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23	// <http://www.gnu.org/licenses/>.
24
25	/** @file parallel/unique_copy.h
26	* @brief Parallel implementations of std::unique_copy().
27	* This file is a GNU parallel extension to the Standard C++ Library.
28	*/
29
30	// Written by Robert Geisberger and Robin Dapp.
31
32	#ifndef _GLIBCXX_PARALLEL_UNIQUE_COPY_H
33	#define _GLIBCXX_PARALLEL_UNIQUE_COPY_H 1
34
35	#include <parallel/parallel.h>
36	#include <parallel/multiseq_selection.h>
37
38	namespace __gnu_parallel
39	{
40	/** @brief Parallel std::unique_copy(), w/__o explicit equality predicate.
41	* @param __first Begin iterator of input sequence.
42	* @param __last End iterator of input sequence.
43	* @param __result Begin iterator of result __sequence.
44	* @param __binary_pred Equality predicate.
45	* @return End iterator of result __sequence. */
46	template<typename _IIter,
47	class _OutputIterator,
48	class _BinaryPredicate>
49	_OutputIterator
50	__parallel_unique_copy(_IIter __first, _IIter __last,
51	_OutputIterator __result,
52	_BinaryPredicate __binary_pred)
53	{
54	_GLIBCXX_CALL(__last - __first)
55
56	typedef std::iterator_traits<_IIter> _TraitsType;
57	typedef typename _TraitsType::value_type _ValueType;
58	typedef typename _TraitsType::difference_type _DifferenceType;
59
60	_DifferenceType __size = __last - __first;
61
62	if (__size == 0)
63	return __result;
64
65	// Let the first thread process two parts.
66	_DifferenceType *__counter;
67	_DifferenceType *__borders;
68
69	_ThreadIndex __num_threads = __get_max_threads();
70	// First part contains at least one element.
71	# pragma omp parallel num_threads(__num_threads)
72	{
73	# pragma omp single
74	{
75	__num_threads = omp_get_num_threads();
76	__borders = new _DifferenceType[__num_threads + 2];
77	__equally_split(__size, __num_threads + 1, __borders);
78	__counter = new _DifferenceType[__num_threads + 1];
79	}
80
81	_ThreadIndex __iam = omp_get_thread_num();
82
83	_DifferenceType __begin, __end;
84
85	// Check for length without duplicates
86	// Needed for position in output
87	_DifferenceType __i = 0;
88	_OutputIterator __out = __result;
89
90	if (__iam == 0)
91	{
92	__begin = __borders[0] + 1; // == 1
93	__end = __borders[__iam + 1];
94
95	++__i;
96	__out++ = __first;
97
98	for (_IIter __iter = __first + __begin; __iter < __first + __end;
99	++__iter)
100	{
101	if (!__binary_pred(__iter, (__iter - 1)))
102	{
103	++__i;
104	__out++ = __iter;
105	}
106	}
107	}
108	else
109	{
110	__begin = __borders[__iam]; //one part
111	__end = __borders[__iam + 1];
112
113	for (_IIter __iter = __first + __begin; __iter < __first + __end;
114	++__iter)
115	{
116	if (!__binary_pred(__iter, (__iter - 1)))
117	++__i;
118	}
119	}
120	__counter[__iam] = __i;
121
122	// Last part still untouched.
123	_DifferenceType __begin_output;
124
125	# pragma omp barrier
126
127	// Store result in output on calculated positions.
128	__begin_output = 0;
129
130	if (__iam == 0)
131	{
132	for (_ThreadIndex __t = 0; __t < __num_threads; ++__t)
133	__begin_output += __counter[__t];
134
135	__i = 0;
136
137	_OutputIterator __iter_out = __result + __begin_output;
138
139	__begin = __borders[__num_threads];
140	__end = __size;
141
142	for (_IIter __iter = __first + __begin; __iter < __first + __end;
143	++__iter)
144	{
145	if (__iter == __first
146	\|\| !__binary_pred(__iter, (__iter - 1)))
147	{
148	++__i;
149	__iter_out++ = __iter;
150	}
151	}
152
153	__counter[__num_threads] = __i;
154	}
155	else
156	{
157	for (_ThreadIndex __t = 0; __t < __iam; __t++)
158	__begin_output += __counter[__t];
159
160	_OutputIterator __iter_out = __result + __begin_output;
161	for (_IIter __iter = __first + __begin; __iter < __first + __end;
162	++__iter)
163	{
164	if (!__binary_pred(__iter, (__iter - 1)))
165	__iter_out++ = __iter;
166	}
167	}
168	}
169
170	_DifferenceType __end_output = 0;
171	for (_ThreadIndex __t = 0; __t < __num_threads + 1; __t++)
172	__end_output += __counter[__t];
173
174	delete[] __borders;
175
176	return __result + __end_output;
177	}
178
179	/** @brief Parallel std::unique_copy(), without explicit equality predicate
180	* @param __first Begin iterator of input sequence.
181	* @param __last End iterator of input sequence.
182	* @param __result Begin iterator of result __sequence.
183	* @return End iterator of result __sequence. */
184	template<typename _IIter, class _OutputIterator>
185	inline _OutputIterator
186	__parallel_unique_copy(_IIter __first, _IIter __last,
187	_OutputIterator __result)
188	{
189	typedef typename std::iterator_traits<_IIter>::value_type
190	_ValueType;
191	return __parallel_unique_copy(__first, __last, __result,
192	std::equal_to<_ValueType>());
193	}
194
195	}//namespace __gnu_parallel
196
197	#endif /* _GLIBCXX_PARALLEL_UNIQUE_COPY_H */