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
  21 template<class Generator>
  22 class generator_iterator
  23   : public iterator_facade<
  24         generator_iterator<Generator>
  25       , typename Generator::result_type
  26       , single_pass_traversal_tag
  27       , typename Generator::result_type const&
  28     >
  29 {
  30     typedef iterator_facade<
  31         generator_iterator<Generator>
  32       , typename Generator::result_type
  33       , single_pass_traversal_tag
  34       , typename Generator::result_type const&
  35     > super_t;
  36
  37  public:
  38     generator_iterator() {}
  39     generator_iterator(Generator* g) : m_g(g), m_value((*m_g)()) {}
  40
  41     void increment()
  42     {
  43         m_value = (*m_g)();
  44     }
  45
  46     const typename Generator::result_type&
  47     dereference() const
  48     {
  49         return m_value;
  50     }
  51
  52     bool equal(generator_iterator const& y) const
  53     {
  54         return this->m_g == y.m_g && this->m_value == y.m_value;
  55     }
  56
  57  private:
  58     Generator* m_g;
  59     typename Generator::result_type m_value;
  60 };
  61
  62 template<class Generator>
  63 struct generator_iterator_generator
  64 {
  65   typedef generator_iterator<Generator> type;
  66 };
  67
  68 template <class Generator>
  69 inline generator_iterator<Generator>
  70 make_generator_iterator(Generator & gen)
  71 {
  72   typedef generator_iterator<Generator> result_t;
  73   return result_t(&gen);
  74 }
  75
  76 } // namespace boost
  77
  78
  79 #endif // BOOST_ITERATOR_ADAPTOR_GENERATOR_ITERATOR_HPP
  80