forked from KolibriOS/kolibrios
b5b499b8c8
Move to folder with tcc. Part 1 git-svn-id: svn://kolibrios.org@8793 a494cfbc-eb01-0410-851d-a64ba20cac60
109 lines
2.4 KiB
C
109 lines
2.4 KiB
C
#include <time.h>
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#include <sys/ksys.h>
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#include <ctype.h>
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#include <errno.h>
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#include <limits.h>
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#define LEAPOCH (946684800LL + 86400*(31+29))
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#define DAYS_PER_400Y (365*400 + 97)
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#define DAYS_PER_100Y (365*100 + 24)
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#define DAYS_PER_4Y (365*4 + 1)
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static int __secs_to_tm(long long t, struct tm *tm)
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{
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long long days, secs, years;
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int remdays, remsecs, remyears;
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int qc_cycles, c_cycles, q_cycles;
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int months;
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int wday, yday, leap;
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static const char days_in_month[] = {31,30,31,30,31,31,30,31,30,31,31,29};
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// Reject time_t values whose year would overflow int
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if (t < INT_MIN * 31622400LL || t > INT_MAX * 31622400LL)
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return -1;
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secs = t - LEAPOCH;
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days = secs / 86400;
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remsecs = secs % 86400;
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if (remsecs < 0) {
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remsecs += 86400;
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days--;
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}
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wday = (3+days)%7;
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if (wday < 0) wday += 7;
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qc_cycles = days / DAYS_PER_400Y;
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remdays = days % DAYS_PER_400Y;
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if (remdays < 0) {
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remdays += DAYS_PER_400Y;
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qc_cycles--;
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}
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c_cycles = remdays / DAYS_PER_100Y;
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if (c_cycles == 4) c_cycles--;
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remdays -= c_cycles * DAYS_PER_100Y;
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q_cycles = remdays / DAYS_PER_4Y;
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if (q_cycles == 25) q_cycles--;
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remdays -= q_cycles * DAYS_PER_4Y;
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remyears = remdays / 365;
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if (remyears == 4) remyears--;
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remdays -= remyears * 365;
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leap = !remyears && (q_cycles || !c_cycles);
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yday = remdays + 31 + 28 + leap;
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if (yday >= 365+leap) yday -= 365+leap;
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years = remyears + 4*q_cycles + 100*c_cycles + 400LL*qc_cycles;
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for (months=0; days_in_month[months] <= remdays; months++)
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remdays -= days_in_month[months];
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if (months >= 10) {
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months -= 12;
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years++;
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}
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if (years+100 > INT_MAX || years+100 < INT_MIN)
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return -1;
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tm->tm_year = years + 100;
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tm->tm_mon = months + 2;
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tm->tm_mday = remdays + 1;
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tm->tm_wday = wday;
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tm->tm_yday = yday;
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tm->tm_hour = remsecs / 3600;
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tm->tm_min = remsecs / 60 % 60;
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tm->tm_sec = remsecs % 60;
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return 0;
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}
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struct tm *__localtime_r(const time_t *restrict t, struct tm *restrict tm)
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{
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// Reject time_t values whose year would overflow int because
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// __secs_to_zone cannot safely handle them.
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if (*t < INT_MIN * 31622400LL || *t > INT_MAX * 31622400LL) {
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errno = EOVERFLOW;
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return NULL;
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}
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//__secs_to_zone(*t, 0, &tm->tm_isdst, &tm->__tm_gmtoff, 0, &tm->__tm_zone);
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if (__secs_to_tm((long long)*t,tm) < 0) {
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errno = EOVERFLOW;
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return NULL;
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}
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return tm;
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}
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struct tm * localtime (const time_t * timer)
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{
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static struct tm tm;
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return __localtime_r(timer, &tm);
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}
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