iterator_concepts.hpp 7.59 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284
// (C) Copyright Jeremy Siek 2002.
// 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)

#ifndef BOOST_ITERATOR_CONCEPTS_HPP
#define BOOST_ITERATOR_CONCEPTS_HPP

#include <boost/concept_check.hpp>
#include <boost/iterator/iterator_categories.hpp>

// Use boost::detail::iterator_traits to work around some MSVC/Dinkumware problems.
#include <boost/detail/iterator.hpp>

#include <boost/type_traits/is_same.hpp>
#include <boost/type_traits/is_integral.hpp>

#include <boost/mpl/bool.hpp>
#include <boost/mpl/if.hpp>
#include <boost/mpl/and.hpp>
#include <boost/mpl/or.hpp>

#include <boost/static_assert.hpp>

// Use boost/limits to work around missing limits headers on some compilers
#include <boost/limits.hpp>
#include <boost/config.hpp>

#include <algorithm>

#include <boost/concept/detail/concept_def.hpp>

namespace boost_concepts
{
  // Used a different namespace here (instead of "boost") so that the
  // concept descriptions do not take for granted the names in
  // namespace boost.

  //===========================================================================
  // Iterator Access Concepts

  BOOST_concept(ReadableIterator,(Iterator))
    : boost::Assignable<Iterator>
    , boost::CopyConstructible<Iterator>

  {
      typedef BOOST_DEDUCED_TYPENAME boost::detail::iterator_traits<Iterator>::value_type value_type;
      typedef BOOST_DEDUCED_TYPENAME boost::detail::iterator_traits<Iterator>::reference reference;

      BOOST_CONCEPT_USAGE(ReadableIterator)
      {

          value_type v = *i;
          boost::ignore_unused_variable_warning(v);
      }
  private:
      Iterator i;
  };
  
  template <
      typename Iterator
    , typename ValueType = BOOST_DEDUCED_TYPENAME boost::detail::iterator_traits<Iterator>::value_type
  >
  struct WritableIterator
    : boost::CopyConstructible<Iterator>
  {
      BOOST_CONCEPT_USAGE(WritableIterator)
      {
          *i = v;
      }
  private:
      ValueType v;
      Iterator i;
  };

  template <
      typename Iterator
    , typename ValueType = BOOST_DEDUCED_TYPENAME boost::detail::iterator_traits<Iterator>::value_type
  >
  struct WritableIteratorConcept : WritableIterator<Iterator,ValueType> {};
  
  BOOST_concept(SwappableIterator,(Iterator))
  {
      BOOST_CONCEPT_USAGE(SwappableIterator)
      {
          std::iter_swap(i1, i2);
      }
  private:
      Iterator i1;
      Iterator i2;
  };

  BOOST_concept(LvalueIterator,(Iterator))
  {
      typedef typename boost::detail::iterator_traits<Iterator>::value_type value_type;
      
      BOOST_CONCEPT_USAGE(LvalueIterator)
      {
        value_type& r = const_cast<value_type&>(*i);
        boost::ignore_unused_variable_warning(r);
      }
  private:
      Iterator i;
  };

  
  //===========================================================================
  // Iterator Traversal Concepts

  BOOST_concept(IncrementableIterator,(Iterator))
    : boost::Assignable<Iterator>
    , boost::CopyConstructible<Iterator>
  {
      typedef typename boost::iterator_traversal<Iterator>::type traversal_category;

      BOOST_CONCEPT_ASSERT((
        boost::Convertible<
            traversal_category
          , boost::incrementable_traversal_tag
        >));

      BOOST_CONCEPT_USAGE(IncrementableIterator)
      {
          ++i;
          (void)i++;
      }
  private:
      Iterator i;
  };

  BOOST_concept(SinglePassIterator,(Iterator))
    : IncrementableIterator<Iterator>
    , boost::EqualityComparable<Iterator>

  {
      BOOST_CONCEPT_ASSERT((
          boost::Convertible<
             BOOST_DEDUCED_TYPENAME SinglePassIterator::traversal_category
           , boost::single_pass_traversal_tag
          > ));
  };

  BOOST_concept(ForwardTraversal,(Iterator))
    : SinglePassIterator<Iterator>
    , boost::DefaultConstructible<Iterator>
  {
      typedef typename boost::detail::iterator_traits<Iterator>::difference_type difference_type;
      
      BOOST_MPL_ASSERT((boost::is_integral<difference_type>));
      BOOST_MPL_ASSERT_RELATION(std::numeric_limits<difference_type>::is_signed, ==, true);

      BOOST_CONCEPT_ASSERT((
          boost::Convertible<
             BOOST_DEDUCED_TYPENAME ForwardTraversal::traversal_category
           , boost::forward_traversal_tag
          > ));
  };
  
  BOOST_concept(BidirectionalTraversal,(Iterator))
    : ForwardTraversal<Iterator>
  {
      BOOST_CONCEPT_ASSERT((
          boost::Convertible<
             BOOST_DEDUCED_TYPENAME BidirectionalTraversal::traversal_category
           , boost::bidirectional_traversal_tag
          > ));

      BOOST_CONCEPT_USAGE(BidirectionalTraversal)
      {
          --i;
          (void)i--;
      }
   private:
      Iterator i;
  };

  BOOST_concept(RandomAccessTraversal,(Iterator))
    : BidirectionalTraversal<Iterator>
  {
      BOOST_CONCEPT_ASSERT((
          boost::Convertible<
             BOOST_DEDUCED_TYPENAME RandomAccessTraversal::traversal_category
           , boost::random_access_traversal_tag
          > ));

      BOOST_CONCEPT_USAGE(RandomAccessTraversal)
      {
          i += n;
          i = i + n;
          i = n + i;
          i -= n;
          i = i - n;
          n = i - j;
      }
      
   private:
      typename BidirectionalTraversal<Iterator>::difference_type n;
      Iterator i, j;
  };

  //===========================================================================
  // Iterator Interoperability 

  namespace detail
  {
    template <typename Iterator1, typename Iterator2>
    void interop_single_pass_constraints(Iterator1 const& i1, Iterator2 const& i2)
    {
        bool b;
        b = i1 == i2;
        b = i1 != i2;

        b = i2 == i1;
        b = i2 != i1;
        boost::ignore_unused_variable_warning(b);
    }

    template <typename Iterator1, typename Iterator2>
    void interop_rand_access_constraints(
        Iterator1 const& i1, Iterator2 const& i2,
        boost::random_access_traversal_tag, boost::random_access_traversal_tag)
    {
        bool b;
        typename boost::detail::iterator_traits<Iterator2>::difference_type n;
        b = i1 <  i2;
        b = i1 <= i2;
        b = i1 >  i2;
        b = i1 >= i2;
        n = i1 -  i2;

        b = i2 <  i1;
        b = i2 <= i1;
        b = i2 >  i1;
        b = i2 >= i1;
        n = i2 -  i1;
        boost::ignore_unused_variable_warning(b);
        boost::ignore_unused_variable_warning(n);
    }

    template <typename Iterator1, typename Iterator2>
    void interop_rand_access_constraints(
        Iterator1 const&, Iterator2 const&,
        boost::single_pass_traversal_tag, boost::single_pass_traversal_tag)
    { }

  } // namespace detail

  BOOST_concept(InteroperableIterator,(Iterator)(ConstIterator))
  {
   private:
      typedef typename boost::detail::pure_traversal_tag<
          typename boost::iterator_traversal<
              Iterator
          >::type
      >::type traversal_category;

      typedef typename boost::detail::pure_traversal_tag<
          typename boost::iterator_traversal<
              ConstIterator
          >::type
      >::type const_traversal_category;
      
  public:
      BOOST_CONCEPT_ASSERT((SinglePassIterator<Iterator>));
      BOOST_CONCEPT_ASSERT((SinglePassIterator<ConstIterator>));

      BOOST_CONCEPT_USAGE(InteroperableIterator)
      {
          detail::interop_single_pass_constraints(i, ci);
          detail::interop_rand_access_constraints(i, ci, traversal_category(), const_traversal_category());

          ci = i;
      }
      
   private:
      Iterator      i;
      ConstIterator ci;
  };

} // namespace boost_concepts

#include <boost/concept/detail/concept_undef.hpp>

#endif // BOOST_ITERATOR_CONCEPTS_HPP