//---------------------------------------------------------------------------//

// Copyright (c) 2013-2014 Kyle Lutz <kyle.r.lutz@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_IS_SORTED_HPP

#define BOOST_COMPUTE_ALGORITHM_IS_SORTED_HPP

#include <boost/static_assert.hpp>

#include <boost/compute/command_queue.hpp>

#include <boost/compute/system.hpp>

#include <boost/compute/functional/bind.hpp>

#include <boost/compute/functional/operator.hpp>

#include <boost/compute/algorithm/adjacent_find.hpp>

#include <boost/compute/type_traits/is_device_iterator.hpp>

namespace boost {

namespace compute {

/// Returns \c true if the values in the range [\p first, \p last)

/// are in sorted order.

///

/// \param first first element in the range to check

/// \param last last element in the range to check

/// \param compare comparison function (by default \c less)

/// \param queue command queue to perform the operation

///

/// \return \c true if the range [\p first, \p last) is sorted

///

/// Space complexity: \Omega(1)

///

/// \see sort()

template<class InputIterator, class Compare>

inline bool is_sorted(InputIterator first,

InputIterator last,

Compare compare,

command_queue &queue = system::default_queue())

{

BOOST_STATIC_ASSERT(is_device_iterator<InputIterator>::value);

using ::boost::compute::placeholders::_1;

using ::boost::compute::placeholders::_2;

return ::boost::compute::adjacent_find(

first, last, ::boost::compute::bind(compare, _2, _1), queue

) == last;

}

/// \overload

template<class InputIterator>

inline bool is_sorted(InputIterator first,

InputIterator last,

command_queue &queue = system::default_queue())

{

BOOST_STATIC_ASSERT(is_device_iterator<InputIterator>::value);

typedef typename std::iterator_traits<InputIterator>::value_type value_type;

return ::boost::compute::is_sorted(

first, last, ::boost::compute::less<value_type>(), queue

);

}

} // end compute namespace

} // end boost namespace

#endif // BOOST_COMPUTE_ALGORITHM_IS_SORTED_HPP