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#include <time.h>
#include <ctype.h>
#include <limits.h>
#include <stdlib.h>
#include <string.h>
#include "libc.h"
#include "__time.h"
long __timezone = 0;
int __daylight = 0;
char *__tzname[2] = { 0, 0 };
int __dst_offset = 0;
weak_alias(__timezone, timezone);
weak_alias(__daylight, daylight);
weak_alias(__tzname, tzname);
static char std_name[TZNAME_MAX+1];
static char dst_name[TZNAME_MAX+1];
/* all elements are zero-based */
static struct rule {
char month;
char week;
short day;
int time;
} __dst_start, __dst_end;
static void zname(char *d, char **s)
{
int i;
for (i=0; i<TZNAME_MAX && isalpha(d[i]=**s); i++, (*s)++);
d[i] = 0;
}
static int hhmmss(char **s)
{
int ofs = strtol(*s, s, 10)*3600;
if (ofs >= 0) {
if (**s == ':') ofs += strtol(*s+1, s, 10)*60;
if (**s == ':') ofs += strtol(*s+1, s, 10);
} else {
if (**s == ':') ofs -= strtol(*s+1, s, 10)*60;
if (**s == ':') ofs -= strtol(*s+1, s, 10);
}
return ofs;
}
static int dstrule(struct rule *rule, char **s)
{
if (**s != ',') return -1;
switch (*++*s) {
case 'J':
rule->month = 'J';
rule->day = strtol(*s+1, s, 10)-1;
break;
case 'M':
rule->month = strtol(*s+1, s, 10)-1;
if (**s != '.' || rule->month < 0 || rule->month > 11)
return -1;
rule->week = strtol(*s+1, s, 10)-1;
if (**s != '.' || rule->week < 0 || rule->week > 4)
return -1;
rule->day = strtol(*s+1, s, 10);
if (rule->day < 0 || rule->day > 6)
return -1;
break;
default:
rule->month = 'L';
rule->day = strtol(*s+1, s, 10);
break;
}
if (**s == '/') {
(*s)++;
rule->time = hhmmss(s);
} else rule->time = 7200;
return 0;
}
void tzset(void)
{
char *z, *a;
strcpy(std_name, "GMT");
strcpy(dst_name, "GMT");
__tzname[0] = std_name;
__tzname[1] = dst_name;
__timezone = 0;
__daylight = 0;
if (!(z = getenv("TZ")) || !isalpha(*z)) return;
zname(std_name, &z);
__timezone = hhmmss(&z);
zname(dst_name, &z);
if (dst_name[0]) __daylight=1;
a = z;
__dst_offset = hhmmss(&z) - __timezone;
if (z==a) __dst_offset = -3600;
if (dstrule(&__dst_start, &z) || dstrule(&__dst_end, &z))
__daylight = 0;
}
void __tzset(void)
{
static int lock, init;
if (init) return;
LOCK(&lock);
if (!init) tzset();
init=1;
UNLOCK(&lock);
}
static int is_leap(int year)
{
year -= 100;
return !(year&3) && ((year%100) || !(year%400));
}
static int cutoff_yday(struct tm *tm, struct rule *rule)
{
static const char days_in_month[] = {31,28,31,30,31,30,31,31,30,31,30,31};
static const int first_day[] = {0,31,59,90,120,151,181,212,243,273,304,335};
int yday, mday, leap;
switch (rule->month) {
case 'J':
return rule->day + (tm->tm_mon > 1 && is_leap(tm->tm_year));
case 'L':
return rule->day;
default:
yday = first_day[rule->month];
leap = is_leap(tm->tm_year);
if (rule->month > 1 && leap) yday++;
mday = (rule->day - (yday + tm->tm_wday - tm->tm_yday) + 1400)%7 + 7*rule->week;
if (mday >= days_in_month[rule->month] + (leap && rule->month == 1))
mday -= 7;
return mday + yday;
}
}
struct tm *__dst_adjust(struct tm *tm)
{
time_t t;
int start, end, secs;
int after_start, before_end;
if (tm->tm_isdst >= 0) return tm;
if (!__daylight) {
tm->tm_isdst = 0;
return tm;
}
secs = tm->tm_hour*3600 + tm->tm_min*60 + tm->tm_sec;
start = cutoff_yday(tm, &__dst_start);
end = cutoff_yday(tm, &__dst_end);
after_start = (tm->tm_yday > start || (tm->tm_yday == start && secs >= __dst_start.time));
before_end = (tm->tm_yday < end || (tm->tm_yday == end && secs < __dst_end.time));
if ((after_start && before_end) || ((end < start) && (after_start || before_end))) {
tm->tm_sec -= __dst_offset;
tm->tm_isdst = 1;
t = __tm_to_time(tm);
return __time_to_tm(t, tm);
} else tm->tm_isdst = 0;
return tm;
}
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