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/* This is adapted from glibc */
/* Copyright (C) 1991, 1993 Free Software Foundation, Inc */
#define SECS_PER_HOUR 3600L
#define SECS_PER_DAY 86400L
#include <features.h>
#include <time.h>
#include <sys/types.h>
/* This structure contains all the information about a
timezone given in the POSIX standard TZ envariable. */
typedef struct
{
const char *name;
/* When to change. */
enum { J0, J1, M } type; /* Interpretation of: */
unsigned short int m, n, d; /* Month, week, day. */
unsigned int secs; /* Time of day. */
long int offset; /* Seconds east of GMT (west if < 0). */
/* We cache the computed time of change for a
given year so we don't have to recompute it. */
time_t change; /* When to change to this zone. */
int computed_for; /* Year above is computed for. */
} tz_rule;
/* tz_rules[0] is standard, tz_rules[1] is daylight. */
static tz_rule tz_rules[2];
/* Warning -- this function is a stub andd always does UTC
* no matter what it is given */
void tzset (void)
{
tz_rules[0].name = tz_rules[1].name = "UTC";
tz_rules[0].type = tz_rules[1].type = J0;
tz_rules[0].m = tz_rules[0].n = tz_rules[0].d = 0;
tz_rules[1].m = tz_rules[1].n = tz_rules[1].d = 0;
tz_rules[0].secs = tz_rules[1].secs = 0;
tz_rules[0].offset = tz_rules[1].offset = 0L;
tz_rules[0].change = tz_rules[1].change = (time_t) -1;
tz_rules[0].computed_for = tz_rules[1].computed_for = 0;
}
static const unsigned short int __mon_lengths[2][12] = {
/* Normal years. */
{31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},
/* Leap years. */
{31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}
};
void __tm_conv(struct tm *tmbuf, time_t *t, time_t offset)
{
int isdst;
long days, rem;
register int y;
register const unsigned short int *ip;
timezone = -offset;
days = *t / SECS_PER_DAY;
rem = *t % SECS_PER_DAY;
rem += offset;
while (rem < 0) {
rem += SECS_PER_DAY;
--days;
}
while (rem >= SECS_PER_DAY) {
rem -= SECS_PER_DAY;
++days;
}
tmbuf->tm_hour = rem / SECS_PER_HOUR;
rem %= SECS_PER_HOUR;
tmbuf->tm_min = rem / 60;
tmbuf->tm_sec = rem % 60;
/* January 1, 1970 was a Thursday. */
tmbuf->tm_wday = (4 + days) % 7;
if (tmbuf->tm_wday < 0)
tmbuf->tm_wday += 7;
y = 1970;
while (days >= (rem = __isleap(y) ? 366 : 365)) {
++y;
days -= rem;
}
while (days < 0) {
--y;
days += __isleap(y) ? 366 : 365;
}
tmbuf->tm_year = y - 1900;
tmbuf->tm_yday = days;
ip = __mon_lengths[__isleap(y)];
for (y = 0; days >= ip[y]; ++y)
days -= ip[y];
tmbuf->tm_mon = y;
tmbuf->tm_mday = days + 1;
isdst = (*t >= tz_rules[0].change && *t < tz_rules[1].change);
tmbuf->tm_isdst = isdst;
tmbuf->tm_zone = tzname[isdst];
}
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