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-rw-r--r--src/mktime.c71
1 files changed, 71 insertions, 0 deletions
diff --git a/src/mktime.c b/src/mktime.c
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+/*
+ * mktime.c -- converts a struct tm into a time_t
+ *
+ * Copyright (C) 1997 Free Software Foundation, Inc.
+ *
+ * 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 2, 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, write to the Free Software Foundation, Inc., 59
+ * Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+
+/* Written by Philippe De Muyter <phdm@macqel.be>. */
+
+#include <time.h>
+
+static time_t mkgmtime(register struct tm *t)
+{
+ register short month, year;
+ register time_t result;
+ static int m_to_d[12] =
+ {0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334};
+
+ month = t->tm_mon;
+ year = t->tm_year + month / 12 + 1900;
+ month %= 12;
+ if (month < 0) {
+ year -= 1;
+ month += 12;
+ }
+ result = (year - 1970) * 365 + m_to_d[month];
+ if (month <= 1)
+ year -= 1;
+ result += (year - 1968) / 4;
+ result -= (year - 1900) / 100;
+ result += (year - 1600) / 400;
+ result += t->tm_mday;
+ result -= 1;
+ result *= 24;
+ result += t->tm_hour;
+ result *= 60;
+ result += t->tm_min;
+ result *= 60;
+ result += t->tm_sec;
+ return (result);
+}
+
+/*
+ * mktime -- convert tm struct to time_t
+ * if tm_isdst >= 0 use it, else compute it
+ */
+
+time_t mktime(struct tm * t)
+{
+ time_t result;
+
+ tzset();
+ result = mkgmtime(t) + timezone;
+ if (t->tm_isdst > 0
+ || (t->tm_isdst < 0 && localtime(&result)->tm_isdst))
+ result -= 3600;
+ return (result);
+}