Sinipelto
/
banan-os
forked from Bananymous/banan-os
1
0
Fork 0
Code Pull Requests Activity

LibC: Implement mktime

This commit is contained in:
Bananymous 2024-12-05 06:15:36 +02:00
parent 8fa443879c
commit c1a32a4041
1 changed files with 65 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

68
userspace/libraries/LibC/time.cpp
View File

@ -2,6 +2,7 @@
#include <BAN/Math.h>
#include <ctype.h>
#include <errno.h>
#include <string.h>
#include <sys/syscall.h>
#include <time.h>
@ -64,11 +65,8 @@ char* ctime(const time_t* clock)
return ctime_r(clock, buf);
}
struct tm* gmtime_r(const time_t* timer, struct tm* __restrict result)
static constexpr bool is_leap_year(uint64_t year)
{
constexpr auto is_leap_year =
[](time_t year) -> bool
{
if (year % 400 == 0)
return true;
if (year % 100 == 0)
@ -76,8 +74,63 @@ struct tm* gmtime_r(const time_t* timer, struct tm* __restrict result)
if (year % 4 == 0)
return true;
return false;
};
}
time_t mktime(struct tm* tm)
{
if (tm->tm_year < 70)
{
errno = EOVERFLOW;
return -1;
}
tm->tm_min += tm->tm_sec / 60;
tm->tm_sec %= 60;
tm->tm_hour += tm->tm_min / 60;
tm->tm_min %= 60;
tm->tm_mday += tm->tm_hour / 24;
tm->tm_hour %= 24;
static constexpr int month_days[] { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
for (;;)
{
int days_in_month = month_days[tm->tm_mon];
if (tm->tm_mon == 1 && is_leap_year(tm->tm_year))
days_in_month++;
if (tm->tm_mday <= days_in_month)
break;
tm->tm_mday -= days_in_month;
tm->tm_mon++;
}
tm->tm_year += tm->tm_mon / 12;
tm->tm_mon %= 12;
tm->tm_yday = tm->tm_mday - 1;
if (tm->tm_mon > 0)
tm->tm_yday += month_days[tm->tm_mon - 1];
const time_t num_febs = (tm->tm_mon > 1) ? tm->tm_year + 1 : tm->tm_year;
const time_t leap_years = (num_febs - 69) / 4 - (num_febs - 1) / 100 + (num_febs + 299) / 400;
const time_t years = tm->tm_year - 70;
const time_t days = years * 365 + leap_years + tm->tm_yday;
const time_t hours = days * 24 + tm->tm_hour;
const time_t minutes = hours * 60 + tm->tm_min;
const time_t seconds = minutes * 60 + tm->tm_sec;
tm->tm_wday = (days + 4) % 7;
return seconds;
}
struct tm* gmtime_r(const time_t* timer, struct tm* __restrict result)
{
constexpr uint64_t month_days[] { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 };
time_t time = *timer;
@ -483,8 +536,3 @@ void tzset()
{
ASSERT_NOT_REACHED();
}
time_t mktime(struct tm*)
{
ASSERT_NOT_REACHED();
}