ceph/src/boost/libs/iterator/include/boost/generator_iterator.hpp

   1 // (C) Copyright Jens Maurer 2001.
   2 // Distributed under the Boost Software License, Version 1.0. (See
   3 // accompanying file LICENSE_1_0.txt or copy at
   4 // http://www.boost.org/LICENSE_1_0.txt)
   5 //
   6 // Revision History:
   7
   8 // 15 Nov 2001   Jens Maurer
   9 //      created.
  10
  11 //  See http://www.boost.org/libs/utility/iterator_adaptors.htm for documentation.
  12
  13 #ifndef BOOST_ITERATOR_ADAPTOR_GENERATOR_ITERATOR_HPP
  14 #define BOOST_ITERATOR_ADAPTOR_GENERATOR_ITERATOR_HPP
  15
  16 #include <boost/iterator/iterator_facade.hpp>
  17 #include <boost/ref.hpp>
  18
  19 namespace boost {
  20 namespace iterators {
  21
  22 template<class Generator>
  23 class generator_iterator
  24   : public iterator_facade<
  25         generator_iterator<Generator>
  26       , typename Generator::result_type
  27       , single_pass_traversal_tag
  28       , typename Generator::result_type const&
  29     >
  30 {
  31     typedef iterator_facade<
  32         generator_iterator<Generator>
  33       , typename Generator::result_type
  34       , single_pass_traversal_tag
  35       , typename Generator::result_type const&
  36     > super_t;
  37
  38  public:
  39     generator_iterator() {}
  40     generator_iterator(Generator* g) : m_g(g), m_value((*m_g)()) {}
  41
  42     void increment()
  43     {
  44         m_value = (*m_g)();
  45     }
  46
  47     const typename Generator::result_type&
  48     dereference() const
  49     {
  50         return m_value;
  51     }
  52
  53     bool equal(generator_iterator const& y) const
  54     {
  55         return this->m_g == y.m_g && this->m_value == y.m_value;
  56     }
  57
  58  private:
  59     Generator* m_g;
  60     typename Generator::result_type m_value;
  61 };
  62
  63 template<class Generator>
  64 struct generator_iterator_generator
  65 {
  66   typedef generator_iterator<Generator> type;
  67 };
  68
  69 template <class Generator>
  70 inline generator_iterator<Generator>
  71 make_generator_iterator(Generator & gen)
  72 {
  73   typedef generator_iterator<Generator> result_t;
  74   return result_t(&gen);
  75 }
  76
  77 } // namespace iterators
  78
  79 using iterators::generator_iterator;
  80 using iterators::generator_iterator_generator;
  81 using iterators::make_generator_iterator;
  82
  83 } // namespace boost
  84
  85 #endif // BOOST_ITERATOR_ADAPTOR_GENERATOR_ITERATOR_HPP