rt-thread-official/libc/minilibc/time.c

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#include <time.h>
/* 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),
};
static long int timezone;
static const char days[] = "Sun Mon Tue Wed Thu Fri Sat ";
static const char months[] = "Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec ";
/* seconds per day */
#define SPD 24*60*60
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_r(const time_t *timep, 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;
}
struct tm* localtime_r(const time_t* t, struct tm* r) {
time_t tmp;
struct timezone tz;
gettimeofday(0, &tz);
timezone=tz.tz_minuteswest*60L;
tmp=*t+timezone;
return gmtime_r(&tmp,r);
}
struct tm* localtime(const time_t* t) {
static struct tm tmp;
return localtime_r(t,&tmp);
}
time_t timegm(struct tm *const t) {
register time_t day;
register time_t i;
register time_t years = t->tm_year - 70;
if (t->tm_sec>60) { t->tm_min += t->tm_sec/60; t->tm_sec%=60; }
if (t->tm_min>60) { t->tm_hour += t->tm_min/60; t->tm_min%=60; }
if (t->tm_hour>60) { t->tm_mday += t->tm_hour/60; t->tm_hour%=60; }
if (t->tm_mon>12) { t->tm_year += t->tm_mon/12; t->tm_mon%=12; }
while (t->tm_mday>__spm[1+t->tm_mon]) {
if (t->tm_mon==1 && __isleap(t->tm_year+1900)) {
if (t->tm_mon==31+29) break;
--t->tm_mday;
}
t->tm_mday-=__spm[t->tm_mon];
++t->tm_mon;
if (t->tm_mon>11) { t->tm_mon=0; ++t->tm_year; }
}
if (t->tm_year < 70)
return (time_t) -1;
/* Days since 1970 is 365 * number of years + number of leap years since 1970 */
day = years * 365 + (years + 1) / 4;
/* After 2100 we have to substract 3 leap years for every 400 years
This is not intuitive. Most mktime implementations do not support
dates after 2059, anyway, so we might leave this out for it's
bloat. */
if ((years -= 131) >= 0) {
years /= 100;
day -= (years >> 2) * 3 + 1;
if ((years &= 3) == 3) years--;
day -= years;
}
day += t->tm_yday = __spm [t->tm_mon] + t->tm_mday-1 + ( __isleap (t->tm_year+1900) & (t->tm_mon > 1) );
/* day is now the number of days since 'Jan 1 1970' */
i = 7;
t->tm_wday = (day + 4) % i; /* Sunday=0, Monday=1, ..., Saturday=6 */
i = 24;
day *= i;
i = 60;
return ((day + t->tm_hour) * i + t->tm_min) * i + t->tm_sec;
}
time_t mktime(register struct tm* const t) {
time_t x=timegm(t);
struct timezone tz;
gettimeofday(0, &tz);
timezone=tz.tz_minuteswest*60L;
x+=timezone;
return x;
}
static void num2str(char *c,int i) {
c[0]=i/10+'0';
c[1]=i%10+'0';
}
char *asctime_r(const struct tm *t, char *buf) {
/* "Wed Jun 30 21:49:08 1993\n" */
*(int*)buf=*(int*)(days+(t->tm_wday<<2));
*(int*)(buf+4)=*(int*)(months+(t->tm_mon<<2));
num2str(buf+8,t->tm_mday);
if (buf[8]=='0') buf[8]=' ';
buf[10]=' ';
num2str(buf+11,t->tm_hour);
buf[13]=':';
num2str(buf+14,t->tm_min);
buf[16]=':';
num2str(buf+17,t->tm_sec);
buf[19]=' ';
num2str(buf+20,(t->tm_year+1900)/100);
num2str(buf+22,(t->tm_year+1900)%100);
buf[24]='\n';
return buf;
}
char *asctime(const struct tm *timeptr) {
static char buf[25];
return asctime_r(timeptr,buf);
}
char *ctime(const time_t *timep) {
return asctime(localtime(timep));
}
int gettimeofday (struct timeval *tp, void *ignore)
{
time_t t;
t = time(NULL);
tp->tv_sec = t;
tp->tv_usec = 0;
return 0;
}