trampoline/lib/lib9/tm2sec.c

111 lines
1.9 KiB
C

#include <u.h>
#include <libc.h>
#include "zoneinfo.h"
#define SEC2MIN 60L
#define SEC2HOUR (60L*SEC2MIN)
#define SEC2DAY (24L*SEC2HOUR)
/*
* days per month plus days/year
*/
static int dmsize[] =
{
365, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
};
static int ldmsize[] =
{
366, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
};
/*
* return the days/month for the given year
*/
static int *
yrsize(int y)
{
if((y%4) == 0 && ((y%100) != 0 || (y%400) == 0))
return ldmsize;
else
return dmsize;
}
/*
* compute seconds since Jan 1 1970 GMT
* and convert to our timezone.
*/
long
tm2sec(Tm *tm)
{
Tinfo ti0, ti1, *ti;
long secs;
int i, yday, year, *d2m;
secs = 0;
/*
* seconds per year
*/
year = tm->year + 1900;
for(i = 1970; i < year; i++){
d2m = yrsize(i);
secs += d2m[0] * SEC2DAY;
}
/*
* if mday is set, use mon and mday to compute yday
*/
if(tm->mday){
yday = 0;
d2m = yrsize(year);
for(i=0; i<tm->mon; i++)
yday += d2m[i+1];
yday += tm->mday-1;
}else{
yday = tm->yday;
}
secs += yday * SEC2DAY;
/*
* hours, minutes, seconds
*/
secs += tm->hour * SEC2HOUR;
secs += tm->min * SEC2MIN;
secs += tm->sec;
/*
* Assume the local time zone if zone is not GMT
*/
if(strcmp(tm->zone, "GMT") != 0) {
i = zonelookuptinfo(&ti0, secs);
ti = &ti0;
if (i != -1)
if (ti->tzoff!=0) {
/*
* to what local time period `secs' belongs?
*/
if (ti->tzoff>0) {
/*
* east of GMT; check previous local time transition
*/
if (ti->t+ti->tzoff > secs)
if (zonetinfo(&ti1, i-1)!=-1)
ti = &ti1;
} else
/*
* west of GMT; check next local time transition
*/
if (zonetinfo(&ti1, i+1))
if (ti1.t+ti->tzoff < secs)
ti = &ti1;
// fprint(2, "tt: %ld+%d %ld\n", (long)ti->t, ti->tzoff, (long)secs);
secs -= ti->tzoff;
}
}
if(secs < 0)
secs = 0;
return secs;
}