feat(userspace/libc): implement <time.h> header

Not tested enough!

Signed-off-by: EnderIce2 <enderice2@protonmail.com>

Userspace/libc/include/time.h

@@ -59,7 +59,7 @@ extern "C"
 
 	extern int daylight;
 	extern long timezone;
-	extern char *tzname[];
+	extern char *tzname[2];
 
 	char *asctime(const struct tm *);
 	clock_t clock(void);
@@ -71,11 +71,12 @@ extern "C"
 	char *ctime(const time_t *);
 	double difftime(time_t, time_t);
 	struct tm *getdate(const char *);
-	struct tm *gmtime(const time_t *);
+
-	struct tm *gmtime_r(const time_t *restrict, struct tm *restrict);
+	struct tm *gmtime(const time_t *timer);
-	struct tm *localtime(const time_t *);
+	struct tm *gmtime_r(const time_t *restrict timer, struct tm *restrict result);
-	struct tm *localtime_r(const time_t *restrict, struct tm *restrict);
+	struct tm *localtime(const time_t *timer);
-	time_t mktime(struct tm *);
+	struct tm *localtime_r(const time_t *restrict timer, struct tm *restrict result);
+	time_t mktime(struct tm *timeptr);
 	int nanosleep(const struct timespec *, struct timespec *);
 	size_t strftime(char *restrict, size_t, const char *restrict, const struct tm *restrict);
 	size_t strftime_l(char *restrict, size_t, const char *restrict, const struct tm *restrict, locale_t);

Userspace/libc/src/std/time.c

@@ -0,0 +1,199 @@
+/*
+	This file is part of Fennix C Library.
+
+	Fennix C Library is free software: you can redistribute it and/or
+	modify it under the terms of the GNU General Public License as
+	published by the Free Software Foundation, either version 3 of
+	the License, or (at your option) any later version.
+
+	Fennix C Library is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+	GNU General Public License for more details.
+
+	You should have received a copy of the GNU General Public License
+	along with Fennix C Library. If not, see <https://www.gnu.org/licenses/>.
+*/
+
+#include <time.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+
+export int daylight;
+export long timezone;
+export char *tzname[2];
+
+export char *asctime(const struct tm *);
+export clock_t clock(void);
+export int clock_getcpuclockid(pid_t, clockid_t *);
+export int clock_getres(clockid_t, struct timespec *);
+export int clock_gettime(clockid_t, struct timespec *);
+export int clock_nanosleep(clockid_t, int, const struct timespec *, struct timespec *);
+export int clock_settime(clockid_t, const struct timespec *);
+export char *ctime(const time_t *);
+export double difftime(time_t, time_t);
+export struct tm *getdate(const char *);
+
+export struct tm *gmtime(const time_t *timer)
+{
+	static struct tm result;
+	return gmtime_r(timer, &result);
+}
+
+export struct tm *gmtime_r(const time_t *restrict timer, struct tm *restrict result)
+{
+	if (timer == NULL || result == NULL)
+	{
+		errno = EINVAL;
+		return NULL;
+	}
+
+	time_t t = *timer;
+	struct tm *res = localtime(&t);
+	if (res == NULL)
+		return NULL;
+
+	*result = *res;
+	result->tm_gmtoff = 0;
+	result->tm_zone = "UTC";
+	return result;
+}
+
+export struct tm *localtime(const time_t *timer)
+{
+	static struct tm result;
+	return localtime_r(timer, &result);
+}
+
+export struct tm *localtime_r(const time_t *restrict timer, struct tm *restrict result)
+{
+	if (timer == NULL || result == NULL)
+	{
+		errno = EINVAL;
+		return NULL;
+	}
+
+	tzset();
+	time_t t = *timer;
+	struct tm *gmt = gmtime(&t);
+	if (gmt == NULL)
+		return NULL;
+
+	*result = *gmt;
+	result->tm_isdst = -1;
+	time_t local_time = mktime(result);
+	if (local_time == (time_t)-1)
+		return NULL;
+
+	*result = *localtime(&local_time);
+	return result;
+}
+
+export time_t mktime(struct tm *timeptr)
+{
+	time_t result;
+	struct tm temp;
+	tzset();
+
+	temp = *timeptr;
+	temp.tm_sec += temp.tm_min * 60 + temp.tm_hour * 3600 + temp.tm_mday * 86400;
+	temp.tm_min = 0;
+	temp.tm_hour = 0;
+	temp.tm_mday = 1;
+	temp.tm_mon = 0;
+	temp.tm_year = 70;
+	temp.tm_isdst = -1;
+
+	result = mktime(&temp);
+	if (result == (time_t)-1)
+		return (time_t)-1;
+
+	result += timeptr->tm_sec + timeptr->tm_min * 60 + timeptr->tm_hour * 3600;
+	result += (timeptr->tm_mday - 1) * 86400;
+	result += (timeptr->tm_mon) * 2629743;
+	result += (timeptr->tm_year - 70) * 31556926;
+
+	struct tm *local_time = localtime(&result);
+	if (local_time == NULL)
+		return (time_t)-1;
+	*timeptr = *local_time;
+
+	return result;
+}
+
+export int nanosleep(const struct timespec *, struct timespec *);
+export size_t strftime(char *restrict, size_t, const char *restrict, const struct tm *restrict);
+export size_t strftime_l(char *restrict, size_t, const char *restrict, const struct tm *restrict, locale_t);
+export char *strptime(const char *restrict, const char *restrict, struct tm *restrict);
+export time_t time(time_t *);
+export int timer_create(clockid_t, struct sigevent *restrict, timer_t *restrict);
+export int timer_delete(timer_t);
+export int timer_getoverrun(timer_t);
+export int timer_gettime(timer_t, struct itimerspec *);
+export int timer_settime(timer_t, int, const struct itimerspec *restrict, struct itimerspec *restrict);
+export int timespec_get(struct timespec *, int);
+
+export void tzset(void)
+{
+	char *tz = getenv("TZ");
+	if (tz == NULL)
+	{
+		tzname[0] = "UTC";
+		tzname[1] = "UTC";
+		daylight = 0;
+		timezone = 0;
+	}
+	else
+	{
+		if (strcmp(tz, "EST5EDT") == 0)
+		{
+			tzname[0] = "EST";
+			tzname[1] = "EDT";
+			daylight = 1;
+			timezone = 5 * 3600;
+		}
+		else if (strcmp(tz, "GMT0") == 0)
+		{
+			tzname[0] = "GMT";
+			tzname[1] = "GMT";
+			daylight = 0;
+			timezone = 0;
+		}
+		else if (strcmp(tz, "JST-9") == 0)
+		{
+			tzname[0] = "JST";
+			tzname[1] = "JST";
+			daylight = 0;
+			timezone = -9 * 3600;
+		}
+		else if (strcmp(tz, "MET-1MEST") == 0)
+		{
+			tzname[0] = "MET";
+			tzname[1] = "MEST";
+			daylight = 1;
+			timezone = -1 * 3600;
+		}
+		else if (strcmp(tz, "MST7MDT") == 0)
+		{
+			tzname[0] = "MST";
+			tzname[1] = "MDT";
+			daylight = 1;
+			timezone = 7 * 3600;
+		}
+		else if (strcmp(tz, "PST8PDT") == 0)
+		{
+			tzname[0] = "PST";
+			tzname[1] = "PDT";
+			daylight = 1;
+			timezone = 8 * 3600;
+		}
+		else
+		{
+			tzname[0] = "UTC";
+			tzname[1] = "UTC";
+			daylight = 0;
+			timezone = 0;
+		}
+	}
+}