学步园

/*<br /> * linux/kernel/mktime.c<br /> *<br /> * (C) 1991 Linus Torvalds<br /> */<br /> #include <time.h><br /> /*<br /> * This isn't the library routine, it is only used in the kernel.<br /> * as such, we don't care about years<1970 etc, but assume everything<br /> * is ok. Similarly, TZ etc is happily ignored. We just do everything<br /> * as easily as possible. Let's find something public for the library<br /> * routines (although I think minix times is public).<br /> */<br /> /*<br /> * PS. I hate whoever though up the year 1970 - couldn't they have gotten<br /> * a leap-year instead? I also hate Gregorius, pope or no. I'm grumpy.<br /> */<br /> #define MINUTE 60<br /> #define HOUR (60*MINUTE)<br /> #define DAY (24*HOUR)<br /> #define YEAR (365*DAY)<br /> /* interestingly, we assume leap-years */<br /> static int month[12] = {<br /> 0,<br /> DAY*(31),<br /> DAY*(31+29),<br /> DAY*(31+29+31),<br /> DAY*(31+29+31+30),<br /> DAY*(31+29+31+30+31),<br /> DAY*(31+29+31+30+31+30),<br /> DAY*(31+29+31+30+31+30+31),<br /> DAY*(31+29+31+30+31+30+31+31),<br /> DAY*(31+29+31+30+31+30+31+31+30),<br /> DAY*(31+29+31+30+31+30+31+31+30+31),<br /> DAY*(31+29+31+30+31+30+31+31+30+31+30)<br /> };<br /> long kernel_mktime(struct tm * tm)<br /> {<br /> long res;<br /> int year;<br /> year = tm->tm_year - 70;<br /> /* magic offsets (y+1) needed to get leapyears right.*/<br /> res = YEAR*year + DAY*((year+1)/4);<br /> res += month[tm->tm_mon];<br /> /* and (y+2) here. If it wasn't a leap-year, we have to adjust */<br /> if (tm->tm_mon>1 && ((year+2)%4))<br /> res -= DAY;<br /> res += DAY*(tm->tm_mday-1);<br /> res += HOUR*tm->tm_hour;<br /> res += MINUTE*tm->tm_min;<br /> res += tm->tm_sec;<br /> return res;<br /> }<br />