110 lines
4.9 KiB
C++
110 lines
4.9 KiB
C++
// Copyright (c) 2015 Amanieu d'Antras
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//
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the "Software"), to deal
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// in the Software without restriction, including without limitation the rights
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// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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// copies of the Software, and to permit persons to whom the Software is
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// furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in
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// all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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// THE SOFTWARE.
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#ifndef ASYNCXX_H_
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# error "Do not include this header directly, include <async++.h> instead."
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#endif
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namespace async {
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namespace detail {
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// Default map function which simply passes its parameter through unmodified
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struct default_map {
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template<typename T>
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T&& operator()(T&& x) const
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{
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return std::forward<T>(x);
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}
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};
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// Internal implementation of parallel_map_reduce that only accepts a
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// partitioner argument.
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template<typename Sched, typename Partitioner, typename Result, typename MapFunc, typename ReduceFunc>
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Result internal_parallel_map_reduce(Sched& sched, Partitioner partitioner, Result init, const MapFunc& map, const ReduceFunc& reduce)
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{
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// Split the partition, run inline if no more splits are possible
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auto subpart = partitioner.split();
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if (subpart.begin() == subpart.end()) {
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Result out = init;
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for (auto&& i: partitioner)
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out = reduce(std::move(out), map(std::forward<decltype(i)>(i)));
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return out;
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}
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// Run the function over each half in parallel
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auto&& t = async::local_spawn(sched, [&sched, &subpart, init, &map, &reduce] {
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return detail::internal_parallel_map_reduce(sched, std::move(subpart), init, map, reduce);
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});
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Result out = detail::internal_parallel_map_reduce(sched, std::move(partitioner), init, map, reduce);
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return reduce(std::move(out), t.get());
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}
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} // namespace detail
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// Run a function for each element in a range and then reduce the results of that function to a single value
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template<typename Sched, typename Range, typename Result, typename MapFunc, typename ReduceFunc>
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Result parallel_map_reduce(Sched& sched, Range&& range, Result init, const MapFunc& map, const ReduceFunc& reduce)
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{
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return detail::internal_parallel_map_reduce(sched, async::to_partitioner(std::forward<Range>(range)), init, map, reduce);
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}
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// Overload with default scheduler
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template<typename Range, typename Result, typename MapFunc, typename ReduceFunc>
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Result parallel_map_reduce(Range&& range, Result init, const MapFunc& map, const ReduceFunc& reduce)
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{
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return async::parallel_map_reduce(::async::default_scheduler(), range, init, map, reduce);
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}
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// Overloads with std::initializer_list
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template<typename Sched, typename T, typename Result, typename MapFunc, typename ReduceFunc>
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Result parallel_map_reduce(Sched& sched, std::initializer_list<T> range, Result init, const MapFunc& map, const ReduceFunc& reduce)
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{
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return async::parallel_map_reduce(sched, async::make_range(range.begin(), range.end()), init, map, reduce);
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}
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template<typename T, typename Result, typename MapFunc, typename ReduceFunc>
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Result parallel_map_reduce(std::initializer_list<T> range, Result init, const MapFunc& map, const ReduceFunc& reduce)
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{
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return async::parallel_map_reduce(async::make_range(range.begin(), range.end()), init, map, reduce);
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}
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// Variant with identity map operation
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template<typename Sched, typename Range, typename Result, typename ReduceFunc>
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Result parallel_reduce(Sched& sched, Range&& range, Result init, const ReduceFunc& reduce)
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{
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return async::parallel_map_reduce(sched, range, init, detail::default_map(), reduce);
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}
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template<typename Range, typename Result, typename ReduceFunc>
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Result parallel_reduce(Range&& range, Result init, const ReduceFunc& reduce)
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{
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return async::parallel_reduce(::async::default_scheduler(), range, init, reduce);
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}
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template<typename Sched, typename T, typename Result, typename ReduceFunc>
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Result parallel_reduce(Sched& sched, std::initializer_list<T> range, Result init, const ReduceFunc& reduce)
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{
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return async::parallel_reduce(sched, async::make_range(range.begin(), range.end()), init, reduce);
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}
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template<typename T, typename Result, typename ReduceFunc>
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Result parallel_reduce(std::initializer_list<T> range, Result init, const ReduceFunc& reduce)
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{
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return async::parallel_reduce(async::make_range(range.begin(), range.end()), init, reduce);
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}
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} // namespace async
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