Check in BASIC date/time functions

include/libsys/datetime.c

@@ -0,0 +1,62 @@
+//
+// date/time functions
+//
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <time.h>
+#include <sys/time.h>
+
+// get the date in the form YYYY-MM-DD
+char *_basic_date() {
+    char *buf = _gc_alloc(16);
+    time_t now = time(NULL);
+    struct tm *nowtm = localtime(&now);
+
+    strftime(buf, 15, "%F", nowtm);
+    return buf;
+}
+
+// get the time in 24 hour format
+char *_basic_time() {
+    char *buf = _gc_alloc(16);
+    time_t now = time(NULL);
+    struct tm *nowtm = localtime(&now);
+
+    strftime(buf, 15, "%T", nowtm);
+    return buf;
+}
+
+// set both date and time
+time_t _basic_settime(const char *timestr) {
+    struct tm nowtm;
+    int year, month, day;
+    int hour, minute, second;
+    time_t newtime;
+
+    sscanf(timestr, "%d-%d-%d %i:%i:%i", &year, &month, &day, &hour, &minute, &second);
+
+//    __builtin_printf("settime(%s): read year=%d month=%d\n", timestr, year, month);
+
+    // make year relative to 1900
+    if (year > 100) {
+        year = year - 1900;
+    } else {
+        year = year + 100;
+    }
+    nowtm.tm_sec = second;
+    nowtm.tm_min = minute;
+    nowtm.tm_hour = hour;
+    nowtm.tm_mday = day;
+    nowtm.tm_mon = month-1;
+    nowtm.tm_year = year;
+
+    newtime = mktime(&nowtm);
+
+    struct timeval tv;
+
+    tv.tv_sec = newtime;
+    tv.tv_usec = 0;
+
+    settimeofday(&tv, 0);
+}