boost/iterator/reverse_iterator.hpp

   1 // (C) Copyright David Abrahams 2002.
   2 // (C) Copyright Jeremy Siek    2002.
   3 // (C) Copyright Thomas Witt    2002.
   4 // Distributed under the Boost Software License, Version 1.0. (See
   5 // accompanying file LICENSE_1_0.txt or copy at
   6 // http://www.boost.org/LICENSE_1_0.txt)
   7 #ifndef BOOST_REVERSE_ITERATOR_23022003THW_HPP
   8 #define BOOST_REVERSE_ITERATOR_23022003THW_HPP
   9
  10 #include <boost/next_prior.hpp>
  11 #include <boost/iterator.hpp>
  12 #include <boost/iterator/iterator_adaptor.hpp>
  13
  14 namespace boost
  15 {
  16
  17   //
  18   //
  19   //
  20   template <class Iterator>
  21   class reverse_iterator
  22       : public iterator_adaptor< reverse_iterator<Iterator>, Iterator >
  23   {
  24       typedef iterator_adaptor< reverse_iterator<Iterator>, Iterator > super_t;
  25
  26       friend class iterator_core_access;
  27
  28    public:
  29       reverse_iterator() {}
  30
  31       explicit reverse_iterator(Iterator x)
  32           : super_t(x) {}
  33
  34       template<class OtherIterator>
  35       reverse_iterator(
  36           reverse_iterator<OtherIterator> const& r
  37           , typename enable_if_convertible<OtherIterator, Iterator>::type* = 0
  38           )
  39           : super_t(r.base())
  40       {}
  41
  42    private:
  43       typename super_t::reference dereference() const { return *boost::prior(this->base()); }
  44
  45       void increment() { --this->base_reference(); }
  46       void decrement() { ++this->base_reference(); }
  47
  48       void advance(typename super_t::difference_type n)
  49       {
  50           this->base_reference() += -n;
  51       }
  52
  53       template <class OtherIterator>
  54       typename super_t::difference_type
  55       distance_to(reverse_iterator<OtherIterator> const& y) const
  56       {
  57           return this->base_reference() - y.base();
  58       }
  59   };
  60
  61   template <class BidirectionalIterator>
  62   reverse_iterator<BidirectionalIterator> make_reverse_iterator(BidirectionalIterator x)
  63   {
  64       return reverse_iterator<BidirectionalIterator>(x);
  65   }
  66
  67 } // namespace boost
  68
  69 #endif // BOOST_REVERSE_ITERATOR_23022003THW_HPP