ceph/src/boost/boost/iterator/advance.hpp

   1 // Copyright (C) 2017 Michel Morin.
   2 //
   3 // Distributed under the Boost Software License, Version 1.0.
   4 // (See accompanying file LICENSE_1_0.txt or copy at
   5 // http://www.boost.org/LICENSE_1_0.txt)
   6
   7 #ifndef BOOST_ITERATOR_ADVANCE_HPP
   8 #define BOOST_ITERATOR_ADVANCE_HPP
   9
  10 #include <boost/config.hpp>
  11 #include <boost/detail/workaround.hpp>
  12 #include <boost/iterator/iterator_categories.hpp>
  13
  14 namespace boost {
  15 namespace iterators {
  16
  17     namespace detail {
  18         template <typename InputIterator, typename Distance>
  19         inline BOOST_CXX14_CONSTEXPR void
  20         advance_impl(
  21             InputIterator& it
  22           , Distance n
  23           , incrementable_traversal_tag
  24         )
  25         {
  26             while (n > 0) {
  27                 ++it;
  28                 --n;
  29             }
  30         }
  31
  32 #if BOOST_WORKAROUND(BOOST_GCC_VERSION, >= 40600)
  33 // type-limits warning issued below when n is an unsigned integral
  34 #pragma GCC diagnostic push
  35 #pragma GCC diagnostic ignored "-Wtype-limits"
  36 #endif
  37
  38         template <typename BidirectionalIterator, typename Distance>
  39         inline BOOST_CXX14_CONSTEXPR void
  40         advance_impl(
  41             BidirectionalIterator& it
  42           , Distance n
  43           , bidirectional_traversal_tag
  44         )
  45         {
  46             if (n >= 0) {
  47                 while (n > 0) {
  48                     ++it;
  49                     --n;
  50                 }
  51             }
  52             else {
  53                 while (n < 0) {
  54                     --it;
  55                     ++n;
  56                 }
  57             }
  58         }
  59
  60 #if BOOST_WORKAROUND(BOOST_GCC_VERSION, >= 40600)
  61 #pragma GCC diagnostic pop
  62 #endif
  63
  64         template <typename RandomAccessIterator, typename Distance>
  65         inline BOOST_CXX14_CONSTEXPR void
  66         advance_impl(
  67             RandomAccessIterator& it
  68           , Distance n
  69           , random_access_traversal_tag
  70         )
  71         {
  72             it += n;
  73         }
  74     }
  75
  76     namespace advance_adl_barrier {
  77         template <typename InputIterator, typename Distance>
  78         inline BOOST_CXX14_CONSTEXPR void
  79         advance(InputIterator& it, Distance n)
  80         {
  81             detail::advance_impl(
  82                 it, n, typename iterator_traversal<InputIterator>::type()
  83             );
  84         }
  85     }
  86
  87     using namespace advance_adl_barrier;
  88
  89 } // namespace iterators
  90
  91 using namespace iterators::advance_adl_barrier;
  92
  93 } // namespace boost
  94
  95 #endif