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/*
* Copyright 2008-2013 NVIDIA Corporation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#pragma once
#include <thrust/detail/config.h>
#include <thrust/detail/function.h>
#include <thrust/system/tbb/detail/copy_if.h>
#include <thrust/iterator/iterator_traits.h>
#include <thrust/distance.h>
#include <tbb/blocked_range.h>
#include <tbb/parallel_scan.h>
THRUST_NAMESPACE_BEGIN
namespace system
{
namespace tbb
{
namespace detail
{
namespace copy_if_detail
{
template<typename InputIterator1,
typename InputIterator2,
typename OutputIterator,
typename Predicate,
typename Size>
struct body
{
InputIterator1 first;
InputIterator2 stencil;
OutputIterator result;
thrust::detail::wrapped_function<Predicate,bool> pred;
Size sum;
body(InputIterator1 first, InputIterator2 stencil, OutputIterator result, Predicate pred)
: first(first), stencil(stencil), result(result), pred(pred), sum(0)
{}
body(body& b, ::tbb::split)
: first(b.first), stencil(b.stencil), result(b.result), pred(b.pred), sum(0)
{}
void operator()(const ::tbb::blocked_range<Size>& r, ::tbb::pre_scan_tag)
{
InputIterator2 iter = stencil + r.begin();
for (Size i = r.begin(); i != r.end(); ++i, ++iter)
{
if (pred(*iter))
++sum;
}
}
void operator()(const ::tbb::blocked_range<Size>& r, ::tbb::final_scan_tag)
{
InputIterator1 iter1 = first + r.begin();
InputIterator2 iter2 = stencil + r.begin();
OutputIterator iter3 = result + sum;
for (Size i = r.begin(); i != r.end(); ++i, ++iter1, ++iter2)
{
if (pred(*iter2))
{
*iter3 = *iter1;
++sum;
++iter3;
}
}
}
void reverse_join(body& b)
{
sum = b.sum + sum;
}
void assign(body& b)
{
sum = b.sum;
}
}; // end body
} // end copy_if_detail
template<typename InputIterator1,
typename InputIterator2,
typename OutputIterator,
typename Predicate>
OutputIterator copy_if(tag,
InputIterator1 first,
InputIterator1 last,
InputIterator2 stencil,
OutputIterator result,
Predicate pred)
{
typedef typename thrust::iterator_difference<InputIterator1>::type Size;
typedef typename copy_if_detail::body<InputIterator1,InputIterator2,OutputIterator,Predicate,Size> Body;
Size n = thrust::distance(first, last);
if (n != 0)
{
Body body(first, stencil, result, pred);
::tbb::parallel_scan(::tbb::blocked_range<Size>(0,n), body);
thrust::advance(result, body.sum);
}
return result;
} // end copy_if()
} // end detail
} // end tbb
} // end system
THRUST_NAMESPACE_END
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