111 lines
3.5 KiB
C++
111 lines
3.5 KiB
C++
// Copyright (c) 2011 Aaron Graham
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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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// The purpose of this example is to demonstrate the use of the advance parser.
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//[qi_advance_includes
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#include <boost/spirit/include/qi.hpp>
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#include <boost/spirit/include/phoenix_operator.hpp>
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#include <boost/spirit/repository/include/qi_advance.hpp>
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//]
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#include <list>
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#include <string>
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//[qi_advance_namespaces
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namespace qi = boost::spirit::qi;
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using boost::spirit::repository::qi::advance;
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//]
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namespace client
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{
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//[qi_advance_grammar
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template <typename Iterator>
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struct advance_grammar : qi::grammar<Iterator, qi::locals<int> >
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{
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advance_grammar() : advance_grammar::base_type(start)
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{
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using qi::byte_;
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using qi::eoi;
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using namespace qi::labels;
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start
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= byte_ [_a = _1]
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>> advance(_a)
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>> "boost"
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>> byte_ [_a = _1]
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>> (advance(_a) | "qi") // note alternative when advance fails
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>> eoi
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;
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}
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qi::rule<Iterator, qi::locals<int> > start;
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};
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//]
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}
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int main()
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{
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// This parser is tested with both random access iterators (std::string)
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// and bidirectional iterators (std::list).
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char const* result;
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//[qi_advance_example1
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unsigned char const alt1[] =
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{
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5, // number of bytes to advance
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1, 2, 3, 4, 5, // data to advance through
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'b', 'o', 'o', 's', 't', // word to parse
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2, // number of bytes to advance
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11, 12 // more data to advance through
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// eoi
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};
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std::string const alt1_string(alt1, alt1 + sizeof alt1);
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std::list<unsigned char> const alt1_list(alt1, alt1 + sizeof alt1);
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result =
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qi::parse(alt1_string.begin(), alt1_string.end()
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, client::advance_grammar<std::string::const_iterator>())
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? "succeeded" : "failed";
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std::cout << "Parsing alt1 using random access iterator " << result << std::endl;
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result =
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qi::parse(alt1_list.begin(), alt1_list.end()
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, client::advance_grammar<std::list<unsigned char>::const_iterator>())
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? "succeeded" : "failed";
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std::cout << "Parsing alt1 using bidirectional iterator " << result << std::endl;
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//]
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//[qi_advance_example2
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unsigned char const alt2[] =
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{
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2, // number of bytes to advance
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1, 2, // data to advance through
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'b', 'o', 'o', 's', 't', // word to parse
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4, // number of bytes to advance
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'q', 'i' // alternative (advance won't work)
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// eoi
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};
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std::string const alt2_string(alt2, alt2 + sizeof alt2);
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std::list<unsigned char> const alt2_list(alt2, alt2 + sizeof alt2);
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result =
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qi::parse(alt2_string.begin(), alt2_string.end()
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, client::advance_grammar<std::string::const_iterator>())
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? "succeeded" : "failed";
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std::cout << "Parsing alt2 using random access iterator " << result << std::endl;
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result =
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qi::parse(alt2_list.begin(), alt2_list.end()
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, client::advance_grammar<std::list<unsigned char>::const_iterator>())
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? "succeeded" : "failed";
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std::cout << "Parsing alt2 using bidirectional iterator " << result << std::endl;
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//]
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return 0;
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}
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