4 /* 2000-03-01 (mod 400 year, immediately after feb29 */
5 #define LEAPOCH (946684800LL + 86400*(31+29))
7 #define DAYS_PER_400Y (365*400 + 97)
8 #define DAYS_PER_100Y (365*100 + 24)
9 #define DAYS_PER_4Y (365*4 + 1)
11 int __secs_to_tm(long long t, struct tm *tm)
14 int remdays, remsecs, remyears;
15 int qc_cycles, c_cycles, q_cycles;
18 static const char days_in_month[] = {31,30,31,30,31,31,30,31,30,31,31,29};
20 /* Reject time_t values whose year would overflow int */
21 if (t < INT_MIN * 31622400LL || t > INT_MAX * 31622400LL)
26 remsecs = secs % 86400;
33 if (wday < 0) wday += 7;
35 qc_cycles = days / DAYS_PER_400Y;
36 remdays = days % DAYS_PER_400Y;
38 remdays += DAYS_PER_400Y;
42 c_cycles = remdays / DAYS_PER_100Y;
43 if (c_cycles == 4) c_cycles--;
44 remdays -= c_cycles * DAYS_PER_100Y;
46 q_cycles = remdays / DAYS_PER_4Y;
47 if (q_cycles == 25) q_cycles--;
48 remdays -= q_cycles * DAYS_PER_4Y;
50 remyears = remdays / 365;
51 if (remyears == 4) remyears--;
52 remdays -= remyears * 365;
54 leap = !remyears && (q_cycles || !c_cycles);
55 yday = remdays + 31 + 28 + leap;
56 if (yday >= 365+leap) yday -= 365+leap;
58 years = remyears + 4*q_cycles + 100*c_cycles + 400*qc_cycles;
60 for (months=0; days_in_month[months] <= remdays; months++)
61 remdays -= days_in_month[months];
63 if (years+100 > INT_MAX || years+100 < INT_MIN)
66 tm->tm_year = years + 100;
67 tm->tm_mon = months + 2;
68 if (tm->tm_mon >= 12) {
72 tm->tm_mday = remdays + 1;
76 tm->tm_hour = remsecs / 3600;
77 tm->tm_min = remsecs / 60 % 60;
78 tm->tm_sec = remsecs % 60;