Merge branch 'master' of github.com:jtsiomb/pcboot

[bootcensus] / src / libc / time.c

diff --git a/src/libc/time.c b/src/libc/time.c
new file mode 100644 (file)
index 0000000..ecff673
--- /dev/null
+++ b/src/libc/time.c
@@ -0,0 +1,165 @@
+/*
+pcboot - bootable PC demo/game kernel
+Copyright (C) 2018-2019  John Tsiombikas <nuclear@member.fsf.org>
+
+This program 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.
+
+This program 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 this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
+#include <stdio.h>
+#include "time.h"
+#include "rtc.h"
+#include "timer.h"
+#include "config.h"
+
+#define MINSEC         60
+#define HOURSEC                (60 * MINSEC)
+#define DAYSEC         (24 * HOURSEC)
+#define YEARDAYS(x)    (is_leap_year(x) ? 366 : 365)
+
+/* 1-1-1970 was a thursday */
+#define EPOCH_WDAY     4
+
+static int is_leap_year(int yr);
+
+static int mdays[2][12] = {
+       {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},
+       {31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}
+};
+
+static char *wday[] = {
+       "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
+};
+static char *mon[] = {
+       "Jan", "Feb", "Mar", "Apr", "May", "Jun",
+       "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
+};
+
+
+time_t time(time_t *tp)
+{
+       time_t res = start_time + nticks / TICK_FREQ_HZ;
+
+       if(tp) *tp = res;
+       return res;
+}
+
+char *asctime(struct tm *tm)
+{
+       static char buf[64];
+       return asctime_r(tm, buf);
+}
+
+char *asctime_r(struct tm *tm, char *buf)
+{
+       sprintf(buf, "%s %s %d %02d:%02d:%02d %d\n", wday[tm->tm_wday],
+                       mon[tm->tm_mon], tm->tm_mday, tm->tm_hour, tm->tm_min,
+                       tm->tm_sec, tm->tm_year + 1900);
+       return buf;
+}
+
+time_t mktime(struct tm *tm)
+{
+       int i, num_years = tm->tm_year - 70;
+       int year = 1970;
+       int days = day_of_year(tm->tm_year + 1900, tm->tm_mon, tm->tm_mday - 1);
+
+       /* set correct yearday */
+       tm->tm_yday = days;
+
+       for(i=0; i<num_years; i++) {
+               days += YEARDAYS(year++);
+       }
+
+       /* set wday correctly */
+       tm->tm_wday = (days + EPOCH_WDAY) % 7;
+
+       return (time_t)days * DAYSEC + tm->tm_hour * HOURSEC +
+               tm->tm_min * MINSEC + tm->tm_sec;
+}
+
+struct tm *gmtime(time_t *tp)
+{
+       static struct tm tm;
+       return gmtime_r(tp, &tm);
+}
+
+struct tm *gmtime_r(time_t *tp, struct tm *tm)
+{
+       int year, days, leap, yrdays;
+       time_t t;
+
+       year = 1970;
+       days = *tp / DAYSEC;
+       t = *tp % DAYSEC;
+
+       tm->tm_wday = (days + EPOCH_WDAY) % 7;
+
+       while(days >= (yrdays = YEARDAYS(year))) {
+               days -= yrdays;
+               year++;
+       }
+       tm->tm_year = year - 1900;
+       tm->tm_yday = days;
+
+       leap = is_leap_year(year);
+       tm->tm_mon = 0;
+       while(days >= mdays[leap][tm->tm_mon]) {
+               days -= mdays[leap][tm->tm_mon++];
+       }
+
+       tm->tm_mday = days + 1;
+
+       tm->tm_hour = t / HOURSEC;
+       t %= HOURSEC;
+       tm->tm_min = t / MINSEC;
+       tm->tm_sec = t % MINSEC;
+       return tm;
+}
+
+struct tm *localtime(time_t *tp)
+{
+       static struct tm tm;
+       return localtime_r(tp, &tm);
+}
+
+struct tm *localtime_r(time_t *tp, struct tm *tm)
+{
+       time_t t = *tp + timezone;
+       return gmtime_r(&t, tm);
+}
+
+int day_of_year(int year, int mon, int day)
+{
+       int i, yday, leap;
+
+       leap = is_leap_year(year) ? 1 : 0;
+       yday = day;
+
+       for(i=0; i<mon; i++) {
+               yday += mdays[leap][i];
+       }
+       return yday;
+}
+
+static int is_leap_year(int yr)
+{
+       /* exceptions first */
+       if(yr % 400 == 0) {
+               return 1;
+       }
+       if(yr % 100 == 0) {
+               return 0;
+       }
+       /* standard case */
+       return yr % 4 == 0;
+}