commit d9de09f797e53933d3e77323311ec3a89f0b965b
parent e5dca185c3eb30748b6a54b2d7e0981d1714a814
Author: Roberto E. Vargas Caballero <k0ga@shike2.net>
Date: Thu, 30 Apr 2026 11:53:54 +0200
tests/libc: Add 0078-time
Co-authored-by: Hiltjo Posthuma <hiltjo@codemadness.org>
Diffstat:
3 files changed, 163 insertions(+), 0 deletions(-)
diff --git a/tests/libc/execute/.gitignore b/tests/libc/execute/.gitignore
@@ -76,3 +76,4 @@ test.log
0075-strftime
0076-localeconv
0077-setlocale
+0078-time
diff --git a/tests/libc/execute/0078-time.c b/tests/libc/execute/0078-time.c
@@ -0,0 +1,161 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+
+/*
+output:
+testing
+50592 dates compared, all OK
+done
+end:
+*/
+
+
+#ifndef __unix__
+#define putenv(x) (x)
+/*
+ * Ok, this is by definition undefined behaviour because
+ * we are using the name of a library function. The reallity
+ * is that if you use a static linker then this would
+ * overload the libc getenv and it will work as expected,
+ * but if you use a dynamic linker then the internal
+ * references will be tied to the internal getenv function
+ * and this would not work. For our main use case that is
+ * testing scc libc this is good enough, and with the
+ * fallback to putenv and unsetenv this will work in
+ * the systems we are interested on
+ */
+char *
+getenv(const char *name)
+{
+ if (strcmp(name, "TZ") != 0)
+ return NULL;
+ return "UTC";
+}
+#endif
+
+static long long
+datetounix(long long year, int mon, int day, int hour, int min, int sec)
+{
+ /* seconds in a month in a regular (non-leap) year */
+ static const long secs_through_month[] = {
+ 0, 31 * 86400, 59 * 86400, 90 * 86400,
+ 120 * 86400, 151 * 86400, 181 * 86400, 212 * 86400,
+ 243 * 86400, 273 * 86400, 304 * 86400, 334 * 86400 };
+ int is_leap = 0, cycles, centuries = 0, leaps = 0, rem;
+ long long t;
+
+ /* optimization: handle common range year 1902 up to and including 2038 */
+ if (year - 2ULL < 136) {
+ /* amount of leap days relative to 1970: every 4 years */
+ leaps = (year - 68) >> 2;
+ if (!((year - 68) & 3)) {
+ leaps--;
+ is_leap = 1;
+ } else {
+ is_leap = 0;
+ }
+ t = 31536000 * (year - 70) + (86400 * leaps); /* 365 * 86400 = 31536000 */
+ } else {
+ /* general leap year calculation:
+ leap years occur mostly every 4 years but every 100 years
+ a leap year is skipped unless the year is divisible by 400 */
+ cycles = (year - 100) / 400;
+ rem = (year - 100) % 400;
+ if (rem < 0) {
+ cycles--;
+ rem += 400;
+ }
+ if (!rem) {
+ is_leap = 1;
+ } else {
+ if (rem >= 300) {
+ centuries = 3;
+ rem -= 300;
+ } else if (rem >= 200) {
+ centuries = 2;
+ rem -= 200;
+ } else if (rem >= 100) {
+ centuries = 1;
+ rem -= 100;
+ }
+ if (rem) {
+ leaps = rem / 4U;
+ rem %= 4U;
+ is_leap = !rem;
+ }
+ }
+ leaps += (97 * cycles) + (24 * centuries) - is_leap;
+
+ /* adjust 8 leap days from 1970 up to and including 2000:
+ ((30 * 365) + 8) * 86400 = 946771200 */
+ t = ((year - 100) * 31536000LL) + (leaps * 86400LL) + 946771200LL;
+ }
+ t += secs_through_month[mon];
+ if (is_leap && mon >= 2)
+ t += 86400;
+ t += 86400LL * (day - 1);
+ t += 3600LL * hour;
+ t += 60LL * min;
+ t += sec;
+
+ return t;
+}
+
+void
+testtm(struct tm *tm)
+{
+ time_t t1, t2; /* assume time_t is signed 64-bit */
+ long long ll;
+
+ t1 = mktime(tm);
+ if (t1 == (time_t)-1) {
+ printf("timegm failed for %d, %d, %d, %d, %d, %d\n",
+ tm->tm_year, tm->tm_mon, tm->tm_mday, tm->tm_hour, tm->tm_min, tm->tm_sec);
+ }
+
+ ll = datetounix(tm->tm_year, tm->tm_mon, tm->tm_mday, tm->tm_hour, tm->tm_min, tm->tm_sec);
+ t2 = (time_t)ll;
+
+ if (t1 != t2) {
+ printf("result: %lld != %lld\n", (long long)t1, (long long)t2);
+ printf("for: %d, %d, %d, %d, %d, %d\n",
+ tm->tm_year, tm->tm_mon, tm->tm_mday, tm->tm_hour, tm->tm_min, tm->tm_sec);
+ exit(1);
+ }
+}
+
+int
+main(void)
+{
+ struct tm tm;
+ int y, mon, d;
+ unsigned counter = 0;
+
+ puts("testing");
+ putenv("TZ=UTC");
+
+ for (y = 1902; y < 2038; y++) {
+ for (mon = 0; mon < 12; mon++) {
+ for (d = 1; d <= 31; d++) {
+
+ memset(&tm, 0, sizeof(tm));
+ tm.tm_year = y - 1900;
+ tm.tm_mon = mon - 1;
+ tm.tm_mday = d;
+ tm.tm_hour = 0;
+ tm.tm_min = 0;
+ tm.tm_sec = 0;
+ tm.tm_isdst = -1;
+
+ testtm(&tm);
+ counter++;
+ }
+ }
+ }
+ printf("%u dates compared, all OK\n", counter);
+ puts("done");
+
+ return 0;
+}
diff --git a/tests/libc/execute/libc-tests.lst b/tests/libc/execute/libc-tests.lst
@@ -74,3 +74,4 @@
0075-strftime
0076-localeconv
0077-setlocale
+0078-time
