Click here to Skip to main content
15,860,859 members
Articles / Programming Languages / C++

Wave: a Standard conformant C++ preprocessor library

Rate me:
Please Sign up or sign in to vote.
4.96/5 (58 votes)
10 Jan 200413 min read 392.1K   4.4K   81  
Describes a free and fully Standard conformant C++ preprocessor library
 /*=============================================================================
    Wave: A Standard compliant C++ preprocessor

    Copyright (c) 2001-2003 Hartmut Kaiser
    http://spirit.sourceforge.net/

    Permission to copy, use, modify, sell and distribute this software
    is granted provided this copyright notice appears in all copies.
    This software is provided "as is" without express or implied
    warranty, and with no claim as to its suitability for any purpose.

    See Copyright.txt for full copyright notices and acknowledgements.
=============================================================================*/

#if !defined(TIME_CONVERSION_HELPER_HPP_DA97E389_1797_43BA_82AE_B071064B3EF4_INCLUDED)
#define TIME_CONVERSION_HELPER_HPP_DA97E389_1797_43BA_82AE_B071064B3EF4_INCLUDED

#include <ctime>
#include <boost/spirit/core.hpp>
#include <boost/spirit/symbols.hpp>

///////////////////////////////////////////////////////////////////////////////
namespace wave {
namespace util {

namespace time_conversion {

    using namespace std;    // some systems have std::tm etc. in namespace std
    
///////////////////////////////////////////////////////////////////////////////
//  define, whether the rule's should generate some debug output
#define TRACE_CPP_TIME_CONVERSION \
    (BOOST_SPIRIT_DEBUG_FLAGS_CPP & BOOST_SPIRIT_DEBUG_FLAGS_TIME_CONVERSION) \
    /**/

///////////////////////////////////////////////////////////////////////////////
//  Grammar for parsing a date/time string generated by the C++ compiler from
//  __DATE__ and __TIME__ 
    class time_conversion_grammar :
        public boost::spirit::grammar<time_conversion_grammar>
    {
    public:
        time_conversion_grammar() : fYearIsCorrected(false)
        {
            memset (&time_stamp, 0, sizeof(tm));
            BOOST_SPIRIT_DEBUG_TRACE_RULE_NAME(*this, "time_conversion_grammar",
                TRACE_CPP_TIME_CONVERSION);
        }
        
        template <typename ScannerT>
        struct definition {
        
            definition(time_conversion_grammar const &self)
            {
                using boost::spirit::int_p;
                using boost::spirit::add;
                
            char const *m[] = {
                    "Jan", "Feb", "Mar", "Apr", "May", "Jun", 
                    "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
                };

                for (int i = 0; i < 12; ++i)
                    add (month, m[i], i);

                time_rule       // expected format is 'Dec 29 2001 11:23:59'
                    =   month[boost::spirit::assign(self.time_stamp.tm_mon)]  
                    >>  int_p[boost::spirit::assign(self.time_stamp.tm_mday)]    
                    >>  int_p[boost::spirit::assign(self.time_stamp.tm_year)]
                    >>  int_p[boost::spirit::assign(self.time_stamp.tm_hour)]  
                    >>  int_p[boost::spirit::assign(self.time_stamp.tm_min)]
                    >>  int_p[boost::spirit::assign(self.time_stamp.tm_sec)]
                    ;
                    
                BOOST_SPIRIT_DEBUG_TRACE_RULE(time_rule, TRACE_CPP_TIME_CONVERSION);
            }
            
            boost::spirit::rule<ScannerT> time_rule;
            boost::spirit::symbols<> month;

            boost::spirit::rule<ScannerT> const&
            start() const { return time_rule; }
        };
    
        void correct_year() 
        { 
            if (!fYearIsCorrected) {
                time_stamp.tm_year -= 1900;
                fYearIsCorrected = true;
            }
        }

        mutable tm time_stamp;
        bool fYearIsCorrected;
    };
    
///////////////////////////////////////////////////////////////////////////////
// calculate the time of the compilation as a std::time_t to ensure correctness 
// of the saved dfa table 
    class time_conversion_helper
    {
    public:
        time_conversion_helper(char const *act_time) : compile_time(0)
        {
            using namespace boost::spirit;
            
        time_conversion_grammar g;

            if (parse (act_time, g, space_p | ch_p(':')).full) {
                g.correct_year();
                compile_time = mktime(&g.time_stamp);
            }
            BOOST_ASSERT(0 != compile_time);        
        }

        time_t get_time() const { return compile_time; }
        
    private:
        time_t compile_time; 
    };

///////////////////////////////////////////////////////////////////////////////
#undef TRACE_CPP_TIME_CONVERSION
}   // namespace time_conversion 

// import time_conversion into the wave::util namespace
using namespace time_conversion;

///////////////////////////////////////////////////////////////////////////////
}   // namespace util
}   // namespace wave

#endif // !defined(TIME_CONVERSION_HELPER_HPP_DA97E389_1797_43BA_82AE_B071064B3EF4_INCLUDED)

By viewing downloads associated with this article you agree to the Terms of Service and the article's licence.

If a file you wish to view isn't highlighted, and is a text file (not binary), please let us know and we'll add colourisation support for it.

License

This article has no explicit license attached to it but may contain usage terms in the article text or the download files themselves. If in doubt please contact the author via the discussion board below.

A list of licenses authors might use can be found here


Written By
United States United States
Actively involved in Boost and the development of the Spirit parser construction framework.

Comments and Discussions