timeformat.cpp

#include <iostream>
#include <time.h>
#include <stdio.h>
#include <string.h>

class TimeFormat
{
    struct {
        time_t abs_ts;
        time_t loc_ts;
        time_t gmt_ts;
        struct tm loc_time_info;
        struct tm gmt_time_info;
    } m_times;
public:

    TimeFormat()
    {
        memset(&m_times, 0, sizeof(m_times));
    }

    template<typename T=time_t>
    void convert(const T t)
    {
        localtime_r(&t,&m_times.loc_time_info);
        gmtime_r(&t,&m_times.gmt_time_info);
        m_times.loc_ts=mktime(&m_times.loc_time_info);
        m_times.gmt_ts=mktime(&m_times.gmt_time_info);

        /*summer time. Get rid of it:*/
            if(m_times.gmt_time_info.tm_isdst==1)
                m_times.gmt_ts-=3600;
    }


    void now()
    {
        time_t t;
         time(&t);
         localtime_r(&t,&m_times.loc_time_info);
         gmtime_r(&t,&m_times.gmt_time_info);

         m_times.loc_ts=mktime(&m_times.loc_time_info);
         m_times.gmt_ts=mktime(&m_times.gmt_time_info);

         /*summer time. Get rid of it:*/
             if(m_times.gmt_time_info.tm_isdst==1)
                 m_times.gmt_ts-=3600;
    }


    operator char* ()
    {


        static char data[256] ;
        snprintf(data, sizeof(data), "Y-%d:M-%d:D-%d:H-%d:M-%d:S-%d", m_times.gmt_time_info.tm_year+1900,
                 m_times.gmt_time_info.tm_mon+1,
                 m_times.gmt_time_info.tm_mday,
                 m_times.gmt_time_info.tm_hour,
                 m_times.gmt_time_info.tm_min,
                 m_times.gmt_time_info.tm_sec);
        return  data;
    }


};


int main(void)
{

    TimeFormat tf;
    time_t t = (time_t)1604337454;
    tf.convert(t);
    char* d = (char*)tf;
    std::cout << d << "\r\n";
    return 0;
}