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Annotation of linux/kernel/mktime.c, revision 1.1.1.1

1.1       root        1: #include <time.h>
                      2: 
                      3: /*
                      4:  * This isn't the library routine, it is only used in the kernel.
                      5:  * as such, we don't care about years<1970 etc, but assume everything
                      6:  * is ok. Similarly, TZ etc is happily ignored. We just do everything
                      7:  * as easily as possible. Let's find something public for the library
                      8:  * routines (although I think minix times is public).
                      9:  */
                     10: /*
                     11:  * PS. I hate whoever though up the year 1970 - couldn't they have gotten
                     12:  * a leap-year instead? I also hate Gregorius, pope or no. I'm grumpy.
                     13:  */
                     14: #define MINUTE 60
                     15: #define HOUR (60*MINUTE)
                     16: #define DAY (24*HOUR)
                     17: #define YEAR (365*DAY)
                     18: 
                     19: /* interestingly, we assume leap-years */
                     20: static int month[12] = {
                     21:        0,
                     22:        DAY*(31),
                     23:        DAY*(31+29),
                     24:        DAY*(31+29+31),
                     25:        DAY*(31+29+31+30),
                     26:        DAY*(31+29+31+30+31),
                     27:        DAY*(31+29+31+30+31+30),
                     28:        DAY*(31+29+31+30+31+30+31),
                     29:        DAY*(31+29+31+30+31+30+31+31),
                     30:        DAY*(31+29+31+30+31+30+31+31+30),
                     31:        DAY*(31+29+31+30+31+30+31+31+30+31),
                     32:        DAY*(31+29+31+30+31+30+31+31+30+31+30)
                     33: };
                     34: 
                     35: long kernel_mktime(struct tm * tm)
                     36: {
                     37:        long res;
                     38:        int year;
                     39: 
                     40:        year = tm->tm_year - 70;
                     41: /* magic offsets (y+1) needed to get leapyears right.*/
                     42:        res = YEAR*year + DAY*((year+1)/4);
                     43:        res += month[tm->tm_mon];
                     44: /* and (y+2) here. If it wasn't a leap-year, we have to adjust */
                     45:        if (tm->tm_mon>1 && ((year+2)%4))
                     46:                res -= DAY;
                     47:        res += DAY*(tm->tm_mday-1);
                     48:        res += HOUR*tm->tm_hour;
                     49:        res += MINUTE*tm->tm_min;
                     50:        res += tm->tm_sec;
                     51:        return res;
                     52: }

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