108 lines
2.5 KiB
C++
108 lines
2.5 KiB
C++
// Copyright (c) 2010 Larry Evans
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//
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// Distributed under the Boost Software License, Version 1.0. (See accompanying
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// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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//Purpose:
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// Demonstrate error in non-classic multi_pass iterator compilation.
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//
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#include <boost/spirit/home/qi.hpp>
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#include <boost/spirit/home/support.hpp>
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#include <boost/spirit/home/support/multi_pass.hpp>
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#include <boost/spirit/home/support/iterators/detail/functor_input_policy.hpp>
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#include <fstream>
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//[iterate_a2m:
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// copied from:
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// http://www.boost.org/doc/libs/1_41_0/libs/spirit/doc/html/spirit/support/multi_pass.html
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// define the function object
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template<typename CharT=char>
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class istreambuf_functor
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{
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public:
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typedef
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std::istreambuf_iterator<CharT>
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buf_iterator_type;
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typedef
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typename buf_iterator_type::int_type
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result_type;
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static
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result_type
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eof;
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istreambuf_functor(void)
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: current_chr(eof)
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{}
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istreambuf_functor(std::ifstream& input)
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: my_first(input)
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, current_chr(eof)
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{}
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result_type operator()()
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{
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buf_iterator_type last;
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if (my_first == last)
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{
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return eof;
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}
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current_chr=*my_first;
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++my_first;
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return current_chr;
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}
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private:
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buf_iterator_type my_first;
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result_type current_chr;
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};
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template<typename CharT>
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typename istreambuf_functor<CharT>::result_type
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istreambuf_functor<CharT>::
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eof
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( istreambuf_functor<CharT>::buf_iterator_type::traits_type::eof()
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)
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;
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//]iterate_a2m:
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typedef istreambuf_functor<char> base_iterator_type;
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typedef
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boost::spirit::multi_pass
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< base_iterator_type
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, boost::spirit::iterator_policies::default_policy
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< boost::spirit::iterator_policies::first_owner
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, boost::spirit::iterator_policies::no_check
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, boost::spirit::iterator_policies::functor_input
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, boost::spirit::iterator_policies::split_std_deque
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>
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>
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chr_iterator_type;
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// ======================================================================
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// Main
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int main()
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{
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std::ifstream in("multi_pass.txt");
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unsigned num_toks=0;
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unsigned const max_toks=10;
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base_iterator_type base_first(in);
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chr_iterator_type chr_first(base_first);
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chr_iterator_type chr_last;
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for
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(
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; (chr_first != chr_last && ++num_toks < max_toks)
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; ++chr_first
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)
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{
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std::cout<<":num_toks="<<num_toks<<":chr="<<*chr_first<<"\n";
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}
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return 0;
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}
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