boost/compute/algorithm/rotate.hpp
//---------------------------------------------------------------------------//
// Copyright (c) 2014 Roshan <thisisroshansmail@gmail.com>
//
// Distributed under the Boost Software License, Version 1.0
// See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt
//
// See http://boostorg.github.com/compute for more information.
//---------------------------------------------------------------------------//
#ifndef BOOST_COMPUTE_ALGORITHM_ROTATE_HPP
#define BOOST_COMPUTE_ALGORITHM_ROTATE_HPP
#include <boost/compute/system.hpp>
#include <boost/compute/algorithm/copy.hpp>
#include <boost/compute/container/vector.hpp>
namespace boost {
namespace compute {
/// Performs left rotation such that element at \p n_first comes to the
/// beginning.
///
/// Space complexity: \Omega(distance(\p first, \p last))
///
/// \see rotate_copy()
template<class InputIterator>
inline void rotate(InputIterator first,
InputIterator n_first,
InputIterator last,
command_queue &queue = system::default_queue())
{
//Handle trivial cases
if (n_first==first || n_first==last)
{
return;
}
//Handle others
typedef typename std::iterator_traits<InputIterator>::value_type T;
size_t count = detail::iterator_range_size(first, n_first);
size_t count2 = detail::iterator_range_size(first, last);
const context &context = queue.get_context();
vector<T> temp(count2, context);
::boost::compute::copy(first, last, temp.begin(), queue);
::boost::compute::copy(temp.begin()+count, temp.end(), first, queue);
::boost::compute::copy(temp.begin(), temp.begin()+count, last-count, queue);
}
} //end compute namespace
} //end boost namespace
#endif // BOOST_COMPUTE_ALGORITHM_ROTATE_HPP