Edit: for_each_selectors.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/for_each_selectors.h * @brief Functors representing different tasks to be plugged into the * generic parallelization methods for embarrassingly parallel functions. * This file is a GNU parallel extension to the Standard C++ Library. */ // Written by Felix Putze. #ifndef _GLIBCXX_PARALLEL_FOR_EACH_SELECTORS_H #define _GLIBCXX_PARALLEL_FOR_EACH_SELECTORS_H 1 #include <parallel/basic_iterator.h> namespace __gnu_parallel { /** @brief Generic __selector for embarrassingly parallel functions. */ template<typename _It> struct __generic_for_each_selector { /** @brief _Iterator on last element processed; needed for some * algorithms (e. g. std::transform()). */ _It _M_finish_iterator; }; /** @brief std::for_each() selector. */ template<typename _It> struct __for_each_selector : public __generic_for_each_selector<_It> { /** @brief Functor execution. * @param __o Operator. * @param __i iterator referencing object. */ template<typename _Op> bool operator()(_Op& __o, _It __i) { __o(*__i); return true; } }; /** @brief std::generate() selector. */ template<typename _It> struct __generate_selector : public __generic_for_each_selector<_It> { /** @brief Functor execution. * @param __o Operator. * @param __i iterator referencing object. */ template<typename _Op> bool operator()(_Op& __o, _It __i) { *__i = __o(); return true; } }; /** @brief std::fill() selector. */ template<typename _It> struct __fill_selector : public __generic_for_each_selector<_It> { /** @brief Functor execution. * @param __v Current value. * @param __i iterator referencing object. */ template<typename _ValueType> bool operator()(_ValueType& __v, _It __i) { *__i = __v; return true; } }; /** @brief std::transform() __selector, one input sequence variant. */ template<typename _It> struct __transform1_selector : public __generic_for_each_selector<_It> { /** @brief Functor execution. * @param __o Operator. * @param __i iterator referencing object. */ template<typename _Op> bool operator()(_Op& __o, _It __i) { *__i.second = __o(*__i.first); return true; } }; /** @brief std::transform() __selector, two input sequences variant. */ template<typename _It> struct __transform2_selector : public __generic_for_each_selector<_It> { /** @brief Functor execution. * @param __o Operator. * @param __i iterator referencing object. */ template<typename _Op> bool operator()(_Op& __o, _It __i) { *__i._M_third = __o(*__i._M_first, *__i._M_second); return true; } }; /** @brief std::replace() selector. */ template<typename _It, typename _Tp> struct __replace_selector : public __generic_for_each_selector<_It> { /** @brief Value to replace with. */ const _Tp& __new_val; /** @brief Constructor * @param __new_val Value to replace with. */ explicit __replace_selector(const _Tp &__new_val) : __new_val(__new_val) {} /** @brief Functor execution. * @param __v Current value. * @param __i iterator referencing object. */ bool operator()(_Tp& __v, _It __i) { if (*__i == __v) *__i = __new_val; return true; } }; /** @brief std::replace() selector. */ template<typename _It, typename _Op, typename _Tp> struct __replace_if_selector : public __generic_for_each_selector<_It> { /** @brief Value to replace with. */ const _Tp& __new_val; /** @brief Constructor. * @param __new_val Value to replace with. */ explicit __replace_if_selector(const _Tp &__new_val) : __new_val(__new_val) { } /** @brief Functor execution. * @param __o Operator. * @param __i iterator referencing object. */ bool operator()(_Op& __o, _It __i) { if (__o(*__i)) *__i = __new_val; return true; } }; /** @brief std::count() selector. */ template<typename _It, typename _Diff> struct __count_selector : public __generic_for_each_selector<_It> { /** @brief Functor execution. * @param __v Current value. * @param __i iterator referencing object. * @return 1 if count, 0 if does not count. */ template<typename _ValueType> _Diff operator()(_ValueType& __v, _It __i) { return (__v == *__i) ? 1 : 0; } }; /** @brief std::count_if () selector. */ template<typename _It, typename _Diff> struct __count_if_selector : public __generic_for_each_selector<_It> { /** @brief Functor execution. * @param __o Operator. * @param __i iterator referencing object. * @return 1 if count, 0 if does not count. */ template<typename _Op> _Diff operator()(_Op& __o, _It __i) { return (__o(*__i)) ? 1 : 0; } }; /** @brief std::accumulate() selector. */ template<typename _It> struct __accumulate_selector : public __generic_for_each_selector<_It> { /** @brief Functor execution. * @param __o Operator (unused). * @param __i iterator referencing object. * @return The current value. */ template<typename _Op> typename std::iterator_traits<_It>::value_type operator()(_Op __o, _It __i) { return *__i; } }; /** @brief std::inner_product() selector. */ template<typename _It, typename _It2, typename _Tp> struct __inner_product_selector : public __generic_for_each_selector<_It> { /** @brief Begin iterator of first sequence. */ _It __begin1_iterator; /** @brief Begin iterator of second sequence. */ _It2 __begin2_iterator; /** @brief Constructor. * @param __b1 Begin iterator of first sequence. * @param __b2 Begin iterator of second sequence. */ explicit __inner_product_selector(_It __b1, _It2 __b2) : __begin1_iterator(__b1), __begin2_iterator(__b2) { } /** @brief Functor execution. * @param __mult Multiplication functor. * @param __current iterator referencing object. * @return Inner product elemental __result. */ template<typename _Op> _Tp operator()(_Op __mult, _It __current) { typename std::iterator_traits<_It>::difference_type __position = __current - __begin1_iterator; return __mult(*__current, *(__begin2_iterator + __position)); } }; /** @brief Selector that just returns the passed iterator. */ template<typename _It> struct __identity_selector : public __generic_for_each_selector<_It> { /** @brief Functor execution. * @param __o Operator (unused). * @param __i iterator referencing object. * @return Passed iterator. */ template<typename _Op> _It operator()(_Op __o, _It __i) { return __i; } }; /** @brief Selector that returns the difference between two adjacent * __elements. */ template<typename _It> struct __adjacent_difference_selector : public __generic_for_each_selector<_It> { template<typename _Op> bool operator()(_Op& __o, _It __i) { typename _It::first_type __go_back_one = __i.first; --__go_back_one; *__i.second = __o(*__i.first, *__go_back_one); return true; } }; /** @brief Functor doing nothing * * For some __reduction tasks (this is not a function object, but is * passed as __selector __dummy parameter. */ struct _Nothing { /** @brief Functor execution. * @param __i iterator referencing object. */ template<typename _It> void operator()(_It __i) { } }; /** @brief Reduction function doing nothing. */ struct _DummyReduct { bool operator()(bool, bool) const { return true; } }; /** @brief Reduction for finding the maximum element, using a comparator. */ template<typename _Compare, typename _It> struct __min_element_reduct { _Compare& __comp; explicit __min_element_reduct(_Compare &__c) : __comp(__c) { } _It operator()(_It __x, _It __y) { return (__comp(*__x, *__y)) ? __x : __y; } }; /** @brief Reduction for finding the maximum element, using a comparator. */ template<typename _Compare, typename _It> struct __max_element_reduct { _Compare& __comp; explicit __max_element_reduct(_Compare& __c) : __comp(__c) { } _It operator()(_It __x, _It __y) { return (__comp(*__x, *__y)) ? __y : __x; } }; /** @brief General reduction, using a binary operator. */ template<typename _BinOp> struct __accumulate_binop_reduct { _BinOp& __binop; explicit __accumulate_binop_reduct(_BinOp& __b) : __binop(__b) { } template<typename _Result, typename _Addend> _Result operator()(const _Result& __x, const _Addend& __y) { return __binop(__x, __y); } }; } #endif /* _GLIBCXX_PARALLEL_FOR_EACH_SELECTORS_H */
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