1 /*
2 * Distributed under the Boost Software License, Version 1.0.(See accompanying
3 * file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt.)
4 *
5 * See http://www.boost.org/libs/iostreams for documentation.
6
7 * File: boost/iostreams/filter/grep.hpp
8 * Date: Mon May 26 17:48:45 MDT 2008
9 * Copyright: 2008 CodeRage, LLC
10 * Author: Jonathan Turkanis
11 * Contact: turkanis at coderage dot com
12 *
13 * Defines the class template basic_grep_filter and its specializations
14 * grep_filter and wgrep_filter.
15 */
16
17 #ifndef BOOST_IOSTREAMS_GREP_FILTER_HPP_INCLUDED
18 #define BOOST_IOSTREAMS_GREP_FILTER_HPP_INCLUDED
19
20 #if defined(_MSC_VER)
21 # pragma once
22 #endif
23
24 #include <iostream>
25
26 #include <memory> // allocator.
27 #include <boost/iostreams/char_traits.hpp>
28 #include <boost/iostreams/filter/line.hpp>
29 #include <boost/iostreams/pipeline.hpp>
30 #include <boost/regex.hpp>
31
32 namespace boost { namespace iostreams {
33
34 namespace grep {
35
36 const int invert = 1;
37 const int whole_line = invert << 1;
38
39 } // End namespace grep.
40
41 template< typename Ch,
42 typename Tr = regex_traits<Ch>,
43 typename Alloc = std::allocator<Ch> >
44 class basic_grep_filter : public basic_line_filter<Ch, Alloc> {
45 private:
46 typedef basic_line_filter<Ch, Alloc> base_type;
47 public:
48 typedef typename base_type::char_type char_type;
49 typedef typename base_type::category category;
50 typedef char_traits<char_type> traits_type;
51 typedef typename base_type::string_type string_type;
52 typedef basic_regex<Ch, Tr> regex_type;
53 typedef regex_constants::match_flag_type match_flag_type;
54 basic_grep_filter( const regex_type& re,
55 match_flag_type match_flags =
56 regex_constants::match_default,
57 int options = 0 );
count() const58 int count() const { return count_; }
59
60 template<typename Sink>
close(Sink & snk,BOOST_IOS::openmode which)61 void close(Sink& snk, BOOST_IOS::openmode which)
62 {
63 base_type::close(snk, which);
64 options_ &= ~f_initialized;
65 }
66 private:
do_filter(const string_type & line)67 virtual string_type do_filter(const string_type& line)
68 {
69 if ((options_ & f_initialized) == 0) {
70 options_ |= f_initialized;
71 count_ = 0;
72 }
73 bool matches = (options_ & grep::whole_line) ?
74 regex_match(line, re_, match_flags_) :
75 regex_search(line, re_, match_flags_);
76 if (options_ & grep::invert)
77 matches = !matches;
78 if (matches)
79 ++count_;
80 return matches ? line + traits_type::newline() : string_type();
81 }
82
83 // Private flags bitwise OR'd with constants from namespace grep
84 enum flags_ {
85 f_initialized = 65536
86 };
87
88 regex_type re_;
89 match_flag_type match_flags_;
90 int options_;
91 int count_;
92 };
93 BOOST_IOSTREAMS_PIPABLE(basic_grep_filter, 3)
94
95 typedef basic_grep_filter<char> grep_filter;
96 typedef basic_grep_filter<wchar_t> wgrep_filter;
97
98 //------------------Implementation of basic_grep_filter-----------------------//
99
100 template<typename Ch, typename Tr, typename Alloc>
basic_grep_filter(const regex_type & re,match_flag_type match_flags,int options)101 basic_grep_filter<Ch, Tr, Alloc>::basic_grep_filter
102 (const regex_type& re, match_flag_type match_flags, int options)
103 : base_type(true), re_(re), match_flags_(match_flags),
104 options_(options), count_(0)
105 { }
106
107 } } // End namespaces iostreams, boost.
108
109 #endif // #ifndef BOOST_IOSTREAMS_REGEX_FILTER_HPP_INCLUDED
110