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Diffstat (limited to 'gcc-4.4.3/libstdc++-v3/include/parallel/unique_copy.h')
| -rw-r--r-- | gcc-4.4.3/libstdc++-v3/include/parallel/unique_copy.h | 192 |
1 files changed, 192 insertions, 0 deletions
diff --git a/gcc-4.4.3/libstdc++-v3/include/parallel/unique_copy.h b/gcc-4.4.3/libstdc++-v3/include/parallel/unique_copy.h new file mode 100644 index 000000000..a83c2c0c5 --- /dev/null +++ b/gcc-4.4.3/libstdc++-v3/include/parallel/unique_copy.h @@ -0,0 +1,192 @@ +// -*- 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/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 InputIterator, + class OutputIterator, + class BinaryPredicate> + OutputIterator + parallel_unique_copy(InputIterator first, InputIterator last, + OutputIterator result, BinaryPredicate binary_pred) + { + _GLIBCXX_CALL(last - first) + + typedef std::iterator_traits<InputIterator> traits_type; + typedef typename traits_type::value_type value_type; + typedef typename traits_type::difference_type difference_type; + + difference_type size = last - first; + + if (size == 0) + return result; + + // Let the first thread process two parts. + difference_type *counter; + difference_type *borders; + + thread_index_t 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 difference_type[num_threads + 2]; + equally_split(size, num_threads + 1, borders); + counter = new difference_type[num_threads + 1]; + } + + thread_index_t iam = omp_get_thread_num(); + + difference_type begin, end; + + // Check for length without duplicates + // Needed for position in output + difference_type i = 0; + OutputIterator out = result; + + if (iam == 0) + { + begin = borders[0] + 1; // == 1 + end = borders[iam + 1]; + + ++i; + *out++ = *first; + + for (InputIterator 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 (InputIterator iter = first + begin; iter < first + end; ++iter) + { + if (!binary_pred(*iter, *(iter - 1))) + ++i; + } + } + counter[iam] = i; + + // Last part still untouched. + difference_type begin_output; + +# pragma omp barrier + + // Store result in output on calculated positions. + begin_output = 0; + + if (iam == 0) + { + for (int 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 (InputIterator 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 (int t = 0; t < iam; t++) + begin_output += counter[t]; + + OutputIterator iter_out = result + begin_output; + for (InputIterator iter = first + begin; iter < first + end; ++iter) + { + if (!binary_pred(*iter, *(iter-1))) + *iter_out++ = *iter; + } + } + } + + difference_type end_output = 0; + for (int 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 InputIterator, class OutputIterator> + inline OutputIterator + parallel_unique_copy(InputIterator first, InputIterator last, + OutputIterator result) + { + typedef typename std::iterator_traits<InputIterator>::value_type + value_type; + return parallel_unique_copy(first, last, result, + std::equal_to<value_type>()); + } + +}//namespace __gnu_parallel + +#endif /* _GLIBCXX_PARALLEL_UNIQUE_COPY_H */ |