/Src/Dependencies/Boost/boost/spirit/home/support/iterators/detail/input_iterator_policy.hpp

  1//  Copyright (c) 2001 Daniel C. Nuffer
  2//  Copyright (c) 2001-2011 Hartmut Kaiser
  3// 
  4//  Distributed under the Boost Software License, Version 1.0. (See accompanying
  5//  file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
  6
  7#if !defined(BOOST_SPIRIT_ITERATOR_INPUT_ITERATOR_POLICY_MAR_16_2007_1156AM)
  8#define BOOST_SPIRIT_ITERATOR_INPUT_ITERATOR_POLICY_MAR_16_2007_1156AM
  9
 10#include <boost/spirit/home/support/iterators/multi_pass_fwd.hpp>
 11#include <boost/spirit/home/support/iterators/detail/multi_pass.hpp>
 12#include <boost/detail/iterator.hpp> // for boost::detail::iterator_traits
 13#include <boost/assert.hpp>
 14
 15namespace boost { namespace spirit { namespace iterator_policies
 16{
 17    namespace input_iterator_is_valid_test_
 18    {
 19        ///////////////////////////////////////////////////////////////////////
 20        template <typename Token>
 21        inline bool token_is_valid(Token const& c)
 22        {
 23            return c ? true : false;
 24        }
 25    }
 26
 27    ///////////////////////////////////////////////////////////////////////////
 28    //  class input_iterator
 29    //  Implementation of the InputPolicy used by multi_pass
 30    // 
 31    //  The input_iterator encapsulates an input iterator of type T
 32    ///////////////////////////////////////////////////////////////////////////
 33    struct input_iterator
 34    {
 35        ///////////////////////////////////////////////////////////////////////
 36        template <typename T>
 37        class unique // : public detail::default_input_policy
 38        {
 39        private:
 40            typedef
 41                typename boost::detail::iterator_traits<T>::value_type
 42            result_type;
 43
 44        public:
 45            typedef
 46                typename boost::detail::iterator_traits<T>::difference_type
 47            difference_type;
 48            typedef
 49                typename boost::detail::iterator_traits<T>::difference_type
 50            distance_type;
 51            typedef
 52                typename boost::detail::iterator_traits<T>::pointer
 53            pointer;
 54            typedef
 55                typename boost::detail::iterator_traits<T>::reference
 56            reference;
 57            typedef result_type value_type;
 58
 59        protected:
 60            unique() {}
 61            explicit unique(T x) {}
 62
 63            void swap(unique&) {}
 64
 65        public:
 66            template <typename MultiPass>
 67            static void destroy(MultiPass&) {}
 68
 69            template <typename MultiPass>
 70            static typename MultiPass::reference get_input(MultiPass& mp)
 71            {
 72                return *mp.shared()->input_;
 73            }
 74
 75            template <typename MultiPass>
 76            static void advance_input(MultiPass& mp)
 77            {
 78                ++mp.shared()->input_;
 79            }
 80
 81            // test, whether we reached the end of the underlying stream
 82            template <typename MultiPass>
 83            static bool input_at_eof(MultiPass const& mp) 
 84            {
 85                static T const end_iter;
 86                return mp.shared()->input_ == end_iter;
 87            }
 88
 89            template <typename MultiPass>
 90            static bool input_is_valid(MultiPass const& mp, value_type const& t) 
 91            {
 92                using namespace input_iterator_is_valid_test_;
 93                return token_is_valid(t);
 94            }
 95
 96            // no unique data elements
 97        };
 98
 99        ///////////////////////////////////////////////////////////////////////
100        template <typename T>
101        struct shared
102        {
103            explicit shared(T const& input) : input_(input) {}
104
105            T input_;
106        };
107    };
108
109}}}
110
111#endif