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1 #include "time_impl.h" | 1 #include "time_impl.h" |
2 #include <limits.h> | 2 #include <limits.h> |
3 | 3 |
4 /* 2000-03-01 (mod 400 year, immediately after feb29 */ | 4 /* 2000-03-01 (mod 400 year, immediately after feb29 */ |
5 #define LEAPOCH (946684800LL + 86400*(31+29)) | 5 #define LEAPOCH (946684800LL + 86400 * (31 + 29)) |
6 | 6 |
7 #define DAYS_PER_400Y (365*400 + 97) | 7 #define DAYS_PER_400Y (365 * 400 + 97) |
8 #define DAYS_PER_100Y (365*100 + 24) | 8 #define DAYS_PER_100Y (365 * 100 + 24) |
9 #define DAYS_PER_4Y (365*4 + 1) | 9 #define DAYS_PER_4Y (365 * 4 + 1) |
10 | 10 |
11 int __secs_to_tm(long long t, struct tm *tm) | 11 int __secs_to_tm(long long t, struct tm* tm) { |
12 { | 12 long long days, secs, years; |
13 » long long days, secs, years; | 13 int remdays, remsecs, remyears; |
14 » int remdays, remsecs, remyears; | 14 int qc_cycles, c_cycles, q_cycles; |
15 » int qc_cycles, c_cycles, q_cycles; | 15 int months; |
16 » int months; | 16 int wday, yday, leap; |
17 » int wday, yday, leap; | 17 static const char days_in_month[] = {31, 30, 31, 30, 31, 31, |
18 » static const char days_in_month[] = {31,30,31,30,31,31,30,31,30,31,31,29
}; | 18 30, 31, 30, 31, 31, 29}; |
19 | 19 |
20 » /* Reject time_t values whose year would overflow int */ | 20 /* Reject time_t values whose year would overflow int */ |
21 » if (t < INT_MIN * 31622400LL || t > INT_MAX * 31622400LL) | 21 if (t < INT_MIN * 31622400LL || t > INT_MAX * 31622400LL) |
22 » » return -1; | 22 return -1; |
23 | 23 |
24 » secs = t - LEAPOCH; | 24 secs = t - LEAPOCH; |
25 » days = secs / 86400; | 25 days = secs / 86400; |
26 » remsecs = secs % 86400; | 26 remsecs = secs % 86400; |
27 » if (remsecs < 0) { | 27 if (remsecs < 0) { |
28 » » remsecs += 86400; | 28 remsecs += 86400; |
29 » » days--; | 29 days--; |
30 » } | 30 } |
31 | 31 |
32 » wday = (3+days)%7; | 32 wday = (3 + days) % 7; |
33 » if (wday < 0) wday += 7; | 33 if (wday < 0) |
| 34 wday += 7; |
34 | 35 |
35 » qc_cycles = days / DAYS_PER_400Y; | 36 qc_cycles = days / DAYS_PER_400Y; |
36 » remdays = days % DAYS_PER_400Y; | 37 remdays = days % DAYS_PER_400Y; |
37 » if (remdays < 0) { | 38 if (remdays < 0) { |
38 » » remdays += DAYS_PER_400Y; | 39 remdays += DAYS_PER_400Y; |
39 » » qc_cycles--; | 40 qc_cycles--; |
40 » } | 41 } |
41 | 42 |
42 » c_cycles = remdays / DAYS_PER_100Y; | 43 c_cycles = remdays / DAYS_PER_100Y; |
43 » if (c_cycles == 4) c_cycles--; | 44 if (c_cycles == 4) |
44 » remdays -= c_cycles * DAYS_PER_100Y; | 45 c_cycles--; |
| 46 remdays -= c_cycles * DAYS_PER_100Y; |
45 | 47 |
46 » q_cycles = remdays / DAYS_PER_4Y; | 48 q_cycles = remdays / DAYS_PER_4Y; |
47 » if (q_cycles == 25) q_cycles--; | 49 if (q_cycles == 25) |
48 » remdays -= q_cycles * DAYS_PER_4Y; | 50 q_cycles--; |
| 51 remdays -= q_cycles * DAYS_PER_4Y; |
49 | 52 |
50 » remyears = remdays / 365; | 53 remyears = remdays / 365; |
51 » if (remyears == 4) remyears--; | 54 if (remyears == 4) |
52 » remdays -= remyears * 365; | 55 remyears--; |
| 56 remdays -= remyears * 365; |
53 | 57 |
54 » leap = !remyears && (q_cycles || !c_cycles); | 58 leap = !remyears && (q_cycles || !c_cycles); |
55 » yday = remdays + 31 + 28 + leap; | 59 yday = remdays + 31 + 28 + leap; |
56 » if (yday >= 365+leap) yday -= 365+leap; | 60 if (yday >= 365 + leap) |
| 61 yday -= 365 + leap; |
57 | 62 |
58 » years = remyears + 4*q_cycles + 100*c_cycles + 400LL*qc_cycles; | 63 years = remyears + 4 * q_cycles + 100 * c_cycles + 400LL * qc_cycles; |
59 | 64 |
60 » for (months=0; days_in_month[months] <= remdays; months++) | 65 for (months = 0; days_in_month[months] <= remdays; months++) |
61 » » remdays -= days_in_month[months]; | 66 remdays -= days_in_month[months]; |
62 | 67 |
63 » if (years+100 > INT_MAX || years+100 < INT_MIN) | 68 if (years + 100 > INT_MAX || years + 100 < INT_MIN) |
64 » » return -1; | 69 return -1; |
65 | 70 |
66 » tm->tm_year = years + 100; | 71 tm->tm_year = years + 100; |
67 » tm->tm_mon = months + 2; | 72 tm->tm_mon = months + 2; |
68 » if (tm->tm_mon >= 12) { | 73 if (tm->tm_mon >= 12) { |
69 » » tm->tm_mon -=12; | 74 tm->tm_mon -= 12; |
70 » » tm->tm_year++; | 75 tm->tm_year++; |
71 » } | 76 } |
72 » tm->tm_mday = remdays + 1; | 77 tm->tm_mday = remdays + 1; |
73 » tm->tm_wday = wday; | 78 tm->tm_wday = wday; |
74 » tm->tm_yday = yday; | 79 tm->tm_yday = yday; |
75 | 80 |
76 » tm->tm_hour = remsecs / 3600; | 81 tm->tm_hour = remsecs / 3600; |
77 » tm->tm_min = remsecs / 60 % 60; | 82 tm->tm_min = remsecs / 60 % 60; |
78 » tm->tm_sec = remsecs % 60; | 83 tm->tm_sec = remsecs % 60; |
79 | 84 |
80 » return 0; | 85 return 0; |
81 } | 86 } |
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