projects / ceph.git / blame
| Commit | Line | Data |
|---|---|---|
| 7c673cae FG |
1 | //---------------------------------------------------------------------------// |
| 2 | // Copyright (c) 2013 Kyle Lutz <kyle.r.lutz@gmail.com> | |
| 3 | // | |
| 4 | // Distributed under the Boost Software License, Version 1.0 | |
| 5 | // See accompanying file LICENSE_1_0.txt or copy at | |
| 6 | // http://www.boost.org/LICENSE_1_0.txt | |
| 7 | // | |
| 8 | // See http://boostorg.github.com/compute for more information. | |
| 9 | //---------------------------------------------------------------------------// | |
| 10 | ||
| 11 | #ifndef BOOST_COMPUTE_ALGORITHM_DETAIL_COUNT_IF_WITH_REDUCE_HPP | |
| 12 | #define BOOST_COMPUTE_ALGORITHM_DETAIL_COUNT_IF_WITH_REDUCE_HPP | |
| 13 | ||
| 14 | #include <boost/compute/algorithm/reduce.hpp> | |
| 15 | #include <boost/compute/iterator/transform_iterator.hpp> | |
| 16 | #include <boost/compute/types/fundamental.hpp> | |
| 17 | ||
| 18 | namespace boost { | |
| 19 | namespace compute { | |
| 20 | namespace detail { | |
| 21 | ||
| 22 | template<class Predicate, class Arg> | |
| 23 | struct invoked_countable_predicate | |
| 24 | { | |
| 25 | invoked_countable_predicate(Predicate p, Arg a) | |
| 26 | : predicate(p), arg(a) | |
| 27 | { | |
| 28 | } | |
| 29 | ||
| 30 | Predicate predicate; | |
| 31 | Arg arg; | |
| 32 | }; | |
| 33 | ||
| 34 | template<class Predicate, class Arg> | |
| 35 | inline meta_kernel& operator<<(meta_kernel &kernel, | |
| 36 | const invoked_countable_predicate<Predicate, Arg> &expr) | |
| 37 | { | |
| 38 | return kernel << "(" << expr.predicate(expr.arg) << " ? 1 : 0)"; | |
| 39 | } | |
| 40 | ||
| 41 | // the countable_predicate wraps Predicate and converts its result from | |
| 42 | // bool to ulong so that it can be used with reduce() | |
| 43 | template<class Predicate> | |
| 44 | struct countable_predicate | |
| 45 | { | |
| 46 | typedef ulong_ result_type; | |
| 47 | ||
| 48 | countable_predicate(Predicate predicate) | |
| 49 | : m_predicate(predicate) | |
| 50 | { | |
| 51 | } | |
| 52 | ||
| 53 | template<class Arg> | |
| 54 | invoked_countable_predicate<Predicate, Arg> operator()(const Arg &arg) const | |
| 55 | { | |
| 56 | return invoked_countable_predicate<Predicate, Arg>(m_predicate, arg); | |
| 57 | } | |
| 58 | ||
| 59 | Predicate m_predicate; | |
| 60 | }; | |
| 61 | ||
| 62 | // counts the number of elements matching predicate using reduce() | |
| 63 | template<class InputIterator, class Predicate> | |
| 64 | inline size_t count_if_with_reduce(InputIterator first, | |
| 65 | InputIterator last, | |
| 66 | Predicate predicate, | |
| 67 | command_queue &queue) | |
| 68 | { | |
| 69 | countable_predicate<Predicate> reduce_predicate(predicate); | |
| 70 | ||
| 71 | ulong_ count = 0; | |
| 72 | ::boost::compute::reduce( | |
| 73 | ::boost::compute::make_transform_iterator(first, reduce_predicate), | |
| 74 | ::boost::compute::make_transform_iterator(last, reduce_predicate), | |
| 75 | &count, | |
| 76 | ::boost::compute::plus<ulong_>(), | |
| 77 | queue | |
| 78 | ); | |
| 79 | ||
| 80 | return static_cast<size_t>(count); | |
| 81 | } | |
| 82 | ||
| 83 | } // end detail namespace | |
| 84 | } // end compute namespace | |
| 85 | } // end boost namespace | |
| 86 | ||
| 87 | #endif // BOOST_COMPUTE_ALGORITHM_DETAIL_COUNT_IF_WITH_REDUCE_HPP |