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- // Copyright (c) 2001 Daniel C. Nuffer
- // Copyright (c) 2001-2011 Hartmut Kaiser
- //
- // 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)
- #if !defined(BOOST_SPIRIT_BUFFERING_ITERATOR_INPUT_ITERATOR_POLICY_MAR_04_2010_1224AM)
- #define BOOST_SPIRIT_BUFFERING_ITERATOR_INPUT_ITERATOR_POLICY_MAR_04_2010_1224AM
- #include <boost/spirit/home/support/iterators/multi_pass_fwd.hpp>
- #include <boost/spirit/home/support/iterators/detail/multi_pass.hpp>
- #include <boost/spirit/home/support/iterators/detail/input_iterator_policy.hpp>
- #include <boost/assert.hpp>
- #include <iterator> // for std::iterator_traits
- namespace boost { namespace spirit { namespace iterator_policies
- {
- ///////////////////////////////////////////////////////////////////////////
- // class input_iterator
- //
- // Implementation of the InputPolicy used by multi_pass, this is different
- // from the input_iterator policy only as it is buffering the last input
- // character to allow returning it by reference. This is needed for
- // wrapping iterators not buffering the last item (such as the
- // std::istreambuf_iterator). Unfortunately there is no way to
- // automatically figure this out at compile time.
- //
- // The buffering_input_iterator encapsulates an input iterator of type T
- ///////////////////////////////////////////////////////////////////////////
- struct buffering_input_iterator
- {
- ///////////////////////////////////////////////////////////////////////
- template <typename T>
- class unique // : public detail::default_input_policy
- {
- private:
- typedef
- typename std::iterator_traits<T>::value_type
- result_type;
- public:
- typedef
- typename std::iterator_traits<T>::difference_type
- difference_type;
- typedef
- typename std::iterator_traits<T>::difference_type
- distance_type;
- typedef
- typename std::iterator_traits<T>::pointer
- pointer;
- typedef result_type& reference;
- typedef result_type value_type;
- protected:
- unique() {}
- explicit unique(T x) {}
- void swap(unique&) {}
- public:
- template <typename MultiPass>
- static void destroy(MultiPass&) {}
- template <typename MultiPass>
- static typename MultiPass::reference get_input(MultiPass& mp)
- {
- return mp.shared()->get_input();
- }
- template <typename MultiPass>
- static void advance_input(MultiPass& mp)
- {
- BOOST_ASSERT(0 != mp.shared());
- mp.shared()->advance_input();
- }
- // test, whether we reached the end of the underlying stream
- template <typename MultiPass>
- static bool input_at_eof(MultiPass const& mp)
- {
- static T const end_iter;
- return mp.shared()->input_ == end_iter;
- }
- template <typename MultiPass>
- static bool input_is_valid(MultiPass const& mp, value_type const& t)
- {
- return mp.shared()->input_is_valid_;
- }
- // no unique data elements
- };
- ///////////////////////////////////////////////////////////////////////
- template <typename T>
- struct shared
- {
- typedef
- typename std::iterator_traits<T>::value_type
- result_type;
- explicit shared(T const& input)
- : input_(input), curtok_(0), input_is_valid_(false) {}
- void advance_input()
- {
- ++input_;
- input_is_valid_ = false;
- }
- result_type& get_input()
- {
- if (!input_is_valid_) {
- curtok_ = *input_;
- input_is_valid_ = true;
- }
- return curtok_;
- }
- T input_;
- result_type curtok_;
- bool input_is_valid_;
- };
- };
- }}}
- #endif
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