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//---------------------------------------------------------------------------//
// 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_SEARCH_HPP
#define BOOST_COMPUTE_ALGORITHM_SEARCH_HPP
#include <boost/compute/algorithm/detail/search_all.hpp>
#include <boost/compute/algorithm/find.hpp>
#include <boost/compute/container/vector.hpp>
#include <boost/compute/detail/iterator_range_size.hpp>
#include <boost/compute/detail/meta_kernel.hpp>
#include <boost/compute/system.hpp>
namespace boost {
namespace compute {
///
/// \brief Substring matching algorithm
///
/// Searches for the first match of the pattern [p_first, p_last)
/// in text [t_first, t_last).
/// \return Iterator pointing to beginning of first occurrence
///
/// \param t_first Iterator pointing to start of text
/// \param t_last Iterator pointing to end of text
/// \param p_first Iterator pointing to start of pattern
/// \param p_last Iterator pointing to end of pattern
/// \param queue Queue on which to execute
///
template<class TextIterator, class PatternIterator>
inline TextIterator search(TextIterator t_first,
TextIterator t_last,
PatternIterator p_first,
PatternIterator p_last,
command_queue &queue = system::default_queue())
{
// there is no need to check if pattern starts at last n - 1 indices
vector<uint_> matching_indices(
detail::iterator_range_size(t_first, t_last)
- detail::iterator_range_size(p_first, p_last) + 1,
queue.get_context()
);
// search_kernel puts value 1 at every index in vector where pattern starts at
detail::search_kernel<PatternIterator,
TextIterator,
vector<uint_>::iterator> kernel;
kernel.set_range(p_first, p_last, t_first, t_last, matching_indices.begin());
kernel.exec(queue);
vector<uint_>::iterator index = ::boost::compute::find(
matching_indices.begin(), matching_indices.end(), uint_(1), queue
);
// pattern was not found
if(index == matching_indices.end())
return t_last;
return t_first + detail::iterator_range_size(matching_indices.begin(), index);
}
} //end compute namespace
} //end boost namespace
#endif // BOOST_COMPUTE_ALGORITHM_SEARCH_HPP
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