ceph/src/boost/libs/compute/include/boost/compute/detail/iterator_plus_distance.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_DETAIL_ITERATOR_PLUS_DISTANCE_HPP
  12 #define BOOST_COMPUTE_DETAIL_ITERATOR_PLUS_DISTANCE_HPP
  13
  14 #include <iterator>
  15
  16 namespace boost {
  17 namespace compute {
  18 namespace detail {
  19
  20 template<class Iterator, class Distance, class Tag>
  21 inline Iterator iterator_plus_distance(Iterator i, Distance n, Tag)
  22 {
  23     while(n--){ i++; }
  24
  25     return i;
  26 }
  27
  28 template<class Iterator, class Distance>
  29 inline Iterator iterator_plus_distance(Iterator i,
  30                                        Distance n,
  31                                        std::random_access_iterator_tag)
  32 {
  33     typedef typename
  34         std::iterator_traits<Iterator>::difference_type difference_type;
  35
  36     return i + static_cast<difference_type>(n);
  37 }
  38
  39 // similar to std::advance() except returns the advanced iterator and
  40 // also works with iterators that don't define difference_type
  41 template<class Iterator, class Distance>
  42 inline Iterator iterator_plus_distance(Iterator i, Distance n)
  43 {
  44     typedef typename std::iterator_traits<Iterator>::iterator_category tag;
  45
  46     return iterator_plus_distance(i, n, tag());
  47 }
  48
  49 } // end detail namespace
  50 } // end compute namespace
  51 } // end boost namespace
  52
  53 #endif // BOOST_COMPUTE_DETAIL_ITERATOR_PLUS_DISTANCE_HPP