rockbox/apps/plugins/lua/gmtime.c
Maurus Cuelenaere b2581e143d Lua: add support for os library
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@21106 a1c6a512-1295-4272-9138-f99709370657
2009-05-27 22:48:50 +00:00

58 lines
1.3 KiB
C

#include <time.h>
/* seconds per day */
#define SPD 24*60*60
/* days per month -- nonleap! */
const short __spm[13] =
{ 0,
(31),
(31+28),
(31+28+31),
(31+28+31+30),
(31+28+31+30+31),
(31+28+31+30+31+30),
(31+28+31+30+31+30+31),
(31+28+31+30+31+30+31+31),
(31+28+31+30+31+30+31+31+30),
(31+28+31+30+31+30+31+31+30+31),
(31+28+31+30+31+30+31+31+30+31+30),
(31+28+31+30+31+30+31+31+30+31+30+31),
};
int __isleap(int year) {
/* every fourth year is a leap year except for century years that are
* not divisible by 400. */
/* return (year % 4 == 0 && (year % 100 != 0 || year % 400 == 0)); */
return (!(year%4) && ((year%100) || !(year%400)));
}
struct tm *gmtime(const time_t *timep) {
static struct tm r;
time_t i;
register time_t work=*timep%(SPD);
r.tm_sec=work%60; work/=60;
r.tm_min=work%60; r.tm_hour=work/60;
work=*timep/(SPD);
r.tm_wday=(4+work)%7;
for (i=1970; ; ++i) {
register time_t k=__isleap(i)?366:365;
if (work>=k)
work-=k;
else
break;
}
r.tm_year=i-1900;
r.tm_yday=work;
r.tm_mday=1;
if (__isleap(i) && (work>58)) {
if (work==59) r.tm_mday=2; /* 29.2. */
work-=1;
}
for (i=11; i && (__spm[i]>work); --i) ;
r.tm_mon=i;
r.tm_mday+=work-__spm[i];
return &r;
}