//---------------------------------------------------------------------------//
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// Copyright (c) 2013 Kyle Lutz <kyle.r.lutz@gmail.com>
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//
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// Distributed under the Boost Software License, Version 1.0
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// See accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt
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//
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// See http://boostorg.github.com/compute for more information.
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//---------------------------------------------------------------------------//
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#ifndef BOOST_COMPUTE_ALGORITHM_INPLACE_MERGE_HPP
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#define BOOST_COMPUTE_ALGORITHM_INPLACE_MERGE_HPP
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#include <iterator>
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#include <boost/static_assert.hpp>
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#include <boost/compute/system.hpp>
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#include <boost/compute/command_queue.hpp>
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#include <boost/compute/algorithm/merge.hpp>
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#include <boost/compute/container/vector.hpp>
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#include <boost/compute/type_traits/is_device_iterator.hpp>
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namespace boost {
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namespace compute {
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/// Merges the sorted values in the range [\p first, \p middle) with
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/// the sorted values in the range [\p middle, \p last) in-place.
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///
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/// Space complexity: \Omega(n)
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template<class Iterator>
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inline void inplace_merge(Iterator first,
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Iterator middle,
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Iterator last,
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command_queue &queue = system::default_queue())
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{
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BOOST_STATIC_ASSERT(is_device_iterator<Iterator>::value);
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BOOST_ASSERT(first < middle && middle < last);
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typedef typename std::iterator_traits<Iterator>::value_type T;
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const context &context = queue.get_context();
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ptrdiff_t left_size = std::distance(first, middle);
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ptrdiff_t right_size = std::distance(middle, last);
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vector<T> left(left_size, context);
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vector<T> right(right_size, context);
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copy(first, middle, left.begin(), queue);
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copy(middle, last, right.begin(), queue);
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::boost::compute::merge(
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left.begin(),
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left.end(),
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right.begin(),
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right.end(),
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first,
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queue
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);
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}
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} // end compute namespace
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} // end boost namespace
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#endif // BOOST_COMPUTE_ALGORITHM_INPLACE_MERGE_HPP
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