ceph/src/boost/boost/compute/algorithm/mismatch.hpp

   1 //---------------------------------------------------------------------------//
   2 // Copyright (c) 2013 Kyle Lutz <kyle.r.lutz@gmail.com>
   3 //
   4 // Distributed under the Boost Software License, Version 1.0
   5 // See accompanying file LICENSE_1_0.txt or copy at
   6 // http://www.boost.org/LICENSE_1_0.txt
   7 //
   8 // See http://boostorg.github.com/compute for more information.
   9 //---------------------------------------------------------------------------//
  10
  11 #ifndef BOOST_COMPUTE_ALGORITHM_MISMATCH_HPP
  12 #define BOOST_COMPUTE_ALGORITHM_MISMATCH_HPP
  13
  14 #include <iterator>
  15 #include <utility>
  16
  17 #include <boost/compute/system.hpp>
  18 #include <boost/compute/functional.hpp>
  19 #include <boost/compute/command_queue.hpp>
  20 #include <boost/compute/algorithm/find.hpp>
  21 #include <boost/compute/iterator/transform_iterator.hpp>
  22 #include <boost/compute/iterator/zip_iterator.hpp>
  23 #include <boost/compute/functional/detail/unpack.hpp>
  24
  25 namespace boost {
  26 namespace compute {
  27
  28 /// Returns a pair of iterators pointing to the first position where the
  29 /// range [\p first1, \p last1) and the range starting at \p first2
  30 /// differ.
  31 ///
  32 /// Space complexity: \Omega(1)
  33 template<class InputIterator1, class InputIterator2>
  34 inline std::pair<InputIterator1, InputIterator2>
  35 mismatch(InputIterator1 first1,
  36          InputIterator1 last1,
  37          InputIterator2 first2,
  38          command_queue &queue = system::default_queue())
  39 {
  40     typedef typename std::iterator_traits<InputIterator1>::value_type value_type;
  41
  42     ::boost::compute::equal_to<value_type> op;
  43
  44     InputIterator2 last2 = first2 + std::distance(first1, last1);
  45
  46     InputIterator1 iter =
  47         boost::get<0>(
  48             ::boost::compute::find(
  49                 ::boost::compute::make_transform_iterator(
  50                     ::boost::compute::make_zip_iterator(
  51                         boost::make_tuple(first1, first2)
  52                     ),
  53                     detail::unpack(op)
  54                 ),
  55                 ::boost::compute::make_transform_iterator(
  56                     ::boost::compute::make_zip_iterator(
  57                         boost::make_tuple(last1, last2)
  58                     ),
  59                     detail::unpack(op)
  60                 ),
  61                 false,
  62                 queue
  63             ).base().get_iterator_tuple()
  64         );
  65
  66     return std::make_pair(iter, first2 + std::distance(first1, iter));
  67 }
  68
  69 /// \overload
  70 template<class InputIterator1, class InputIterator2>
  71 inline std::pair<InputIterator1, InputIterator2>
  72 mismatch(InputIterator1 first1,
  73          InputIterator1 last1,
  74          InputIterator2 first2,
  75          InputIterator2 last2,
  76          command_queue &queue = system::default_queue())
  77 {
  78     if(std::distance(first1, last1) < std::distance(first2, last2)){
  79         return ::boost::compute::mismatch(first1, last1, first2, queue);
  80     }
  81     else {
  82         return ::boost::compute::mismatch(
  83             first1, first1 + std::distance(first2, last2), first2, queue
  84         );
  85     }
  86 }
  87
  88 } // end compute namespace
  89 } // end boost namespace
  90
  91 #endif // BOOST_COMPUTE_ALGORITHM_MISMATCH_HPP