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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_ITERATOR_LEX_INPUT_POLICY_MAR_16_2007_1205PM)
- #define BOOST_SPIRIT_ITERATOR_LEX_INPUT_POLICY_MAR_16_2007_1205PM
- #include <boost/spirit/home/support/iterators/multi_pass_fwd.hpp>
- #include <boost/spirit/home/support/iterators/detail/multi_pass.hpp>
- namespace boost { namespace spirit { namespace iterator_policies
- {
- ///////////////////////////////////////////////////////////////////////////////
- // class lex_input
- // Implementation of the InputPolicy used by multi_pass
- //
- // The lex_input class gets tokens (integers) from yylex()
- ///////////////////////////////////////////////////////////////////////////
- struct lex_input
- {
- typedef int value_type;
- ///////////////////////////////////////////////////////////////////////
- template <typename T>
- class unique : public detail::default_input_policy
- {
- public:
- typedef std::ptrdiff_t difference_type;
- typedef std::ptrdiff_t distance_type;
- typedef int* pointer;
- typedef int& reference;
- protected:
- unique() {}
- explicit unique(T) {}
- public:
- template <typename MultiPass>
- static typename MultiPass::reference get_input(MultiPass& mp)
- {
- value_type& curtok = mp.shared()->curtok;
- if (-1 == curtok)
- {
- extern int yylex();
- curtok = yylex();
- }
- return curtok;
- }
- template <typename MultiPass>
- static void advance_input(MultiPass& mp)
- {
- extern int yylex();
- mp.shared()->curtok = yylex();
- }
- // test, whether we reached the end of the underlying stream
- template <typename MultiPass>
- static bool input_at_eof(MultiPass const& mp)
- {
- return mp.shared()->curtok == 0;
- }
- template <typename MultiPass>
- static bool input_is_valid(MultiPass const&, value_type const& t)
- {
- return -1 != t;
- }
- };
- ///////////////////////////////////////////////////////////////////////
- template <typename T>
- struct shared
- {
- explicit shared(T) : curtok(-1) {}
- value_type curtok;
- };
- };
- }}}
- #endif
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