1 files changed, 100 insertions, 0 deletions
diff --git a/grub-core/normal/datetime.c b/grub-core/normal/datetime.c
new file mode 100644
index 0000000..44791e1
--- /dev/null
+++ b/grub-core/normal/datetime.c
@@ -0,0 +1,100 @@
+/* datetime.c - Module for common datetime function.  */
+/*
+ *  GRUB  --  GRand Unified Bootloader
+ *  Copyright (C) 2008  Free Software Foundation, Inc.
+ *
+ *  GRUB 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.
+ *
+ *  GRUB 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 GRUB.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <grub/datetime.h>
+
+static char *grub_weekday_names[] =
+{
+  "Sunday",
+  "Monday",
+  "Tuesday",
+  "Wednesday",
+  "Thursday",
+  "Friday",
+  "Saturday",
+};
+
+int
+grub_get_weekday (struct grub_datetime *datetime)
+{
+  int a, y, m;
+
+  a = (14 - datetime->month) / 12;
+  y = datetime->year - a;
+  m = datetime->month + 12 * a - 2;
+
+  return (datetime->day + y + y / 4 - y / 100 + y / 400 + (31 * m / 12)) % 7;
+}
+
+char *
+grub_get_weekday_name (struct grub_datetime *datetime)
+{
+  return grub_weekday_names[grub_get_weekday (datetime)];
+}
+
+#define SECPERMIN 60
+#define SECPERHOUR (60*SECPERMIN)
+#define SECPERDAY (24*SECPERHOUR)
+#define SECPERYEAR (365*SECPERDAY)
+#define SECPER4YEARS (4*SECPERYEAR+SECPERDAY)
+
+
+void
+grub_unixtime2datetime (grub_int32_t nix, struct grub_datetime *datetime)
+{
+  int i;
+  int div;
+  grub_uint8_t months[12] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
+  /* In the period of validity of unixtime all years divisible by 4
+     are bissextile*/
+  /* Convenience: let's have 3 consecutive non-bissextile years
+     at the beginning of the epoch. So count from 1973 instead of 1970 */
+  nix -= 3*SECPERYEAR + SECPERDAY;
+  /* Transform C divisions and modulos to mathematical ones */
+  div = nix / SECPER4YEARS;
+  if (nix < 0)
+    div--;
+  datetime->year = 1973 + 4 * div;
+  nix -= div * SECPER4YEARS;
+
+  /* On 31st December of bissextile years 365 days from the beginning
+     of the year elapsed but year isn't finished yet */
+  if (nix / SECPERYEAR == 4)
+    {
+      datetime->year += 3;
+      nix -= 3*SECPERYEAR;
+    }
+  else
+    {
+      datetime->year += nix / SECPERYEAR;
+      nix %= SECPERYEAR;
+    }
+  for (i = 0; i < 12
+	 && nix >= ((grub_int32_t) (i==1 && datetime->year % 4 == 0
+				    ? 29 : months[i]))*SECPERDAY; i++)
+    nix -= ((grub_int32_t) (i==1 && datetime->year % 4 == 0
+			    ? 29 : months[i]))*SECPERDAY;
+  datetime->month = i + 1;
+  datetime->day = 1 + (nix / SECPERDAY);
+  nix %= SECPERDAY;
+  datetime->hour = (nix / SECPERHOUR);
+  nix %= SECPERHOUR;
+  datetime->minute = nix / SECPERMIN;
+  datetime->second = nix % SECPERMIN;
+}