| 1 | #ifndef BOOST_IOSTREAMS_GREP_HPP_INCLUDED
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| 2 | #define BOOST_IOSTREAMS_GREP_HPP_INCLUDED
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| 3 |
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| 4 | #include <string>
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| 5 | #include <boost/regex.hpp>
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| 6 | #include <boost/iostreams/categories.hpp>
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| 7 | #include <boost/iostreams/operations.hpp>
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| 8 |
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| 9 | namespace boost { namespace iostreams {
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| 10 |
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| 11 | template <typename Ch>
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| 12 | struct basic_grep_filter
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| 13 | {
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| 14 | typedef Ch char_type;
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| 15 | struct category: dual_use, filter_tag { };
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| 16 |
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| 17 | typedef char_traits<char_type> traits_type;
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| 18 | typedef std::basic_string<char_type> string_type;
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| 19 | typedef boost::basic_regex<char_type> regex_type;
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| 20 |
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| 21 | explicit basic_grep_filter(const char* expr)
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| 22 | : expr_(expr), eof_(false), iter_(line_.end())
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| 23 | {
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| 24 | };
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| 25 |
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| 26 | template <typename Source>
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| 27 | typename traits_type::int_type get(Source& src)
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| 28 | {
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| 29 | if (eof_ && iter_ == line_.end())
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| 30 | return EOF;
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| 31 |
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| 32 | if (iter_ != line_.end())
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| 33 | return next();
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| 34 |
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| 35 | for (;;)
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| 36 | {
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| 37 | typename traits_type::int_type c = iostreams::get(src);
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| 38 |
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| 39 | if (c == traits_type::would_block())
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| 40 | return c;
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| 41 |
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| 42 | line_ += c;
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| 43 |
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| 44 | if (traits_type::is_eof(c))
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| 45 | {
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| 46 | eof_ = true;
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| 47 | if (boost::regex_search(line_, expr_))
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| 48 | {
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| 49 | iter_ = line_.begin();
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| 50 | return next();
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| 51 | }
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| 52 |
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| 53 | iter_ = line_.end();
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| 54 | return c;
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| 55 | }
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| 56 |
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| 57 | if (c == traits_type::newline())
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| 58 | {
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| 59 | if (boost::regex_search(line_, expr_))
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| 60 | {
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| 61 | iter_ = line_.begin();
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| 62 | return next();
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| 63 | }
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| 64 |
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| 65 | line_.erase();
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| 66 | iter_ = line_.end();
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| 67 | }
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| 68 | }
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| 69 | }
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| 70 |
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| 71 | template <typename Sink>
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| 72 | bool put(Sink& snk, char_type c)
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| 73 | {
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| 74 | if (!traits_type::is_eof(c))
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| 75 | line_ += c;
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| 76 |
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| 77 | if (traits_type::is_eof(c) || (c == traits_type::newline()))
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| 78 | {
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| 79 | if (boost::regex_search(line_, expr_))
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| 80 | std::for_each(line_.begin(), line_.end(), writer<Sink>(snk));
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| 81 |
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| 82 | if (traits_type::is_eof(c))
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| 83 | iostreams::put(snk, c);
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| 84 |
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| 85 | line_.erase();
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| 86 | }
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| 87 |
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| 88 | return true;
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| 89 | }
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| 90 |
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| 91 | private:
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| 92 | char_type next()
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| 93 | {
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| 94 | char_type c = *iter_;
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| 95 | ++iter_;
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| 96 | if (iter_ == line_.end())
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| 97 | {
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| 98 | line_.erase();
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| 99 | iter_ = line_.end();
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| 100 | }
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| 101 | return c;
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| 102 | }
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| 103 |
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| 104 | template <typename Sink>
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| 105 | struct writer
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| 106 | {
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| 107 | writer(Sink& snk): snk_(snk) { }
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| 108 |
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| 109 | void operator()(const char_type& c)
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| 110 | {
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| 111 | iostreams::put(snk_, c);
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| 112 | }
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| 113 |
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| 114 | private:
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| 115 | Sink& snk_;
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| 116 | };
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| 117 |
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| 118 | private:
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| 119 | regex_type expr_;
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| 120 | bool eof_;
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| 121 | string_type line_;
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| 122 | typename string_type::const_iterator iter_;
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| 123 | };
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| 124 |
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| 125 | typedef basic_grep_filter<char> grep_filter;
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| 126 | typedef basic_grep_filter<wchar_t> wgrep_filter;
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| 127 |
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| 128 | } } // End namespaces iostreams, boost.
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| 129 |
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| 130 | #endif //#ifndef BOOST_IOSTREAMS_GREP_HPP_INCLUDED
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