98 lines
3.5 KiB
Plaintext
98 lines
3.5 KiB
Plaintext
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//---------------------------------------------------------------------------//
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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_SERIAL_MERGE_HPP
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#define BOOST_COMPUTE_ALGORITHM_SERIAL_MERGE_HPP
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#include <iterator>
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#include <boost/compute/command_queue.hpp>
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#include <boost/compute/detail/meta_kernel.hpp>
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#include <boost/compute/detail/iterator_range_size.hpp>
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namespace boost {
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namespace compute {
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namespace detail {
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template<class InputIterator1,
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class InputIterator2,
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class OutputIterator,
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class Compare>
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inline OutputIterator serial_merge(InputIterator1 first1,
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InputIterator1 last1,
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InputIterator2 first2,
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InputIterator2 last2,
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OutputIterator result,
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Compare comp,
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command_queue &queue)
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{
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typedef typename
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std::iterator_traits<InputIterator1>::value_type
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input_type1;
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typedef typename
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std::iterator_traits<InputIterator2>::value_type
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input_type2;
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typedef typename
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std::iterator_traits<OutputIterator>::difference_type
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result_difference_type;
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std::ptrdiff_t size1 = std::distance(first1, last1);
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std::ptrdiff_t size2 = std::distance(first2, last2);
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meta_kernel k("serial_merge");
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k.add_set_arg<uint_>("size1", static_cast<uint_>(size1));
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k.add_set_arg<uint_>("size2", static_cast<uint_>(size2));
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k <<
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"uint i = 0;\n" << // index in result range
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"uint j = 0;\n" << // index in first input range
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"uint k = 0;\n" << // index in second input range
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// fetch initial values from each range
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k.decl<input_type1>("j_value") << " = " << first1[0] << ";\n" <<
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k.decl<input_type2>("k_value") << " = " << first2[0] << ";\n" <<
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// merge values from both input ranges to the result range
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"while(j < size1 && k < size2){\n" <<
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" if(" << comp(k.var<input_type1>("j_value"),
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k.var<input_type2>("k_value")) << "){\n" <<
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" " << result[k.var<uint_>("i++")] << " = j_value;\n" <<
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" j_value = " << first1[k.var<uint_>("++j")] << ";\n" <<
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" }\n" <<
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" else{\n"
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" " << result[k.var<uint_>("i++")] << " = k_value;\n"
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" k_value = " << first2[k.var<uint_>("++k")] << ";\n" <<
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" }\n"
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"}\n"
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// copy any remaining values from first range
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"while(j < size1){\n" <<
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result[k.var<uint_>("i++")] << " = " <<
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first1[k.var<uint_>("j++")] << ";\n" <<
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"}\n"
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// copy any remaining values from second range
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"while(k < size2){\n" <<
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result[k.var<uint_>("i++")] << " = " <<
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first2[k.var<uint_>("k++")] << ";\n" <<
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"}\n";
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// run kernel
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k.exec(queue);
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return result + static_cast<result_difference_type>(size1 + size2);
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}
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} // end detail namespace
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} // end compute namespace
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} // end boost namespace
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#endif // BOOST_COMPUTE_ALGORITHM_SERIAL_MERGE_HPP
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