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1 /*=============================================================================
2     Boost.Wave: A Standard compliant C++ preprocessor library
3     Example demonstrating how to preprocess the token stream generated by a
4     #pragma directive
5 
6     http://www.boost.org/
7 
8     Copyright (c) 2001-2010 Hartmut Kaiser. Distributed under the Boost
9     Software License, Version 1.0. (See accompanying file
10     LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
11 =============================================================================*/
12 
13 #include <iostream>
14 #include <fstream>
15 #include <string>
16 #include <vector>
17 
18 ///////////////////////////////////////////////////////////////////////////////
19 //  Include Wave itself
20 #include <boost/wave.hpp>
21 
22 ///////////////////////////////////////////////////////////////////////////////
23 // Include the lexer stuff
24 #include <boost/wave/cpplexer/cpp_lex_token.hpp>    // token class
25 #include <boost/wave/cpplexer/cpp_lex_iterator.hpp> // lexer class
26 
27 ///////////////////////////////////////////////////////////////////////////////
28 // Include special preprocessing hooks
29 #include "preprocess_pragma_output.hpp"
30 
31 ///////////////////////////////////////////////////////////////////////////////
32 // main entry point
main(int argc,char * argv[])33 int main(int argc, char *argv[])
34 {
35     if (2 != argc) {
36         std::cerr << "Usage: preprocess_pragma_output infile" << std::endl;
37         return -1;
38     }
39 
40 // current file position is saved for exception handling
41 boost::wave::util::file_position_type current_position;
42 
43     try {
44     //  Open and read in the specified input file.
45     std::ifstream instream(argv[1]);
46     std::string instring;
47 
48         if (!instream.is_open()) {
49             std::cerr << "Could not open input file: " << argv[1] << std::endl;
50             return -2;
51         }
52         instream.unsetf(std::ios::skipws);
53         instring = std::string(std::istreambuf_iterator<char>(instream.rdbuf()),
54                                 std::istreambuf_iterator<char>());
55 
56     //  The template boost::wave::cpplexer::lex_token<> is the token type to be
57     //  used by the Wave library.
58         typedef boost::wave::cpplexer::lex_token<> token_type;
59 
60     //  The template boost::wave::cpplexer::lex_iterator<> is the lexer type to
61     //  be used by the Wave library.
62         typedef boost::wave::cpplexer::lex_iterator<token_type> lex_iterator_type;
63 
64     //  This is the resulting context type to use.
65         typedef boost::wave::context<
66             std::string::iterator, lex_iterator_type,
67             boost::wave::iteration_context_policies::load_file_to_string,
68             preprocess_pragma_output_hooks>
69         context_type;
70 
71     // The preprocessor iterator shouldn't be constructed directly. It is
72     // to be generated through a wave::context<> object. This wave:context<>
73     // object is to be used additionally to initialize and define different
74     // parameters of the actual preprocessing (not done here).
75     //
76     // The preprocessing of the input stream is done on the fly behind the
77     // scenes during iteration over the context_type::iterator_type stream.
78     context_type ctx (instring.begin(), instring.end(), argv[1]);
79 
80     // analyze the input file
81     context_type::iterator_type first = ctx.begin();
82     context_type::iterator_type last = ctx.end();
83 
84         while (first != last) {
85             current_position = (*first).get_position();
86             std::cout << (*first).get_value();
87             ++first;
88         }
89     }
90     catch (boost::wave::cpp_exception const& e) {
91     // some preprocessing error
92         std::cerr
93             << e.file_name() << "(" << e.line_no() << "): "
94             << e.description() << std::endl;
95         return 2;
96     }
97     catch (std::exception const& e) {
98     // use last recognized token to retrieve the error position
99         std::cerr
100             << current_position.get_file()
101             << "(" << current_position.get_line() << "): "
102             << "exception caught: " << e.what()
103             << std::endl;
104         return 3;
105     }
106     catch (...) {
107     // use last recognized token to retrieve the error position
108         std::cerr
109             << current_position.get_file()
110             << "(" << current_position.get_line() << "): "
111             << "unexpected exception caught." << std::endl;
112         return 4;
113     }
114     return 0;
115 }
116