--- /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/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 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 Val>
+ bool
+ operator()(Val& 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.third = o(*i.first, *i.second);
+ return true;
+ }
+ };
+
+ /** @brief std::replace() selector. */
+ template<typename It, typename T>
+ struct replace_selector : public generic_for_each_selector<It>
+ {
+ /** @brief Value to replace with. */
+ const T& new_val;
+
+ /** @brief Constructor
+ * @param new_val Value to replace with. */
+ explicit
+ replace_selector(const T &new_val) : new_val(new_val) {}
+
+ /** @brief Functor execution.
+ * @param v Current value.
+ * @param i Iterator referencing object. */
+ bool
+ operator()(T& v, It i)
+ {
+ if (*i == v)
+ *i = new_val;
+ return true;
+ }
+ };
+
+ /** @brief std::replace() selector. */
+ template<typename It, typename Op, typename T>
+ struct replace_if_selector : public generic_for_each_selector<It>
+ {
+ /** @brief Value to replace with. */
+ const T& new_val;
+
+ /** @brief Constructor.
+ * @param new_val Value to replace with. */
+ explicit
+ replace_if_selector(const T &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 Val>
+ Diff
+ operator()(Val& 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 T>
+ 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>
+ T
+ 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;
+ }
+ };
+
+ // XXX move into type_traits?
+ /** @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 dummy_reduct
+ {
+ bool
+ operator()(bool /*x*/, bool /*y*/) const
+ { return true; }
+ };
+
+ /** @brief Reduction for finding the maximum element, using a comparator. */
+ template<typename Comp, typename It>
+ struct min_element_reduct
+ {
+ Comp& comp;
+
+ explicit
+ min_element_reduct(Comp &c) : comp(c) { }
+
+ It
+ operator()(It x, It y)
+ {
+ if (comp(*x, *y))
+ return x;
+ else
+ return y;
+ }
+ };
+
+ /** @brief Reduction for finding the maximum element, using a comparator. */
+ template<typename Comp, typename It>
+ struct max_element_reduct
+ {
+ Comp& comp;
+
+ explicit
+ max_element_reduct(Comp& c) : comp(c) { }
+
+ It
+ operator()(It x, It y)
+ {
+ if (comp(*x, *y))
+ return y;
+ else
+ return 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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