Move mktime_utc() from tvbuff.c to wsutil/time_util.c

Also do little cleanup in mktime_utc (one big #ifndef)

Change-Id: I8f721ba76cad856cfef0a2d78e7f98686f8e4e3f
Reviewed-on: https://code.wireshark.org/review/1327
Reviewed-by: Anders Broman <a.broman58@gmail.com>

1 files changed, 63 insertions, 0 deletions

diff --git a/wsutil/time_util.c b/wsutil/time_util.c
new file mode 100644
index 0000000000..5a7a832923
--- /dev/null
+++ b/wsutil/time_util.c
@@ -0,0 +1,63 @@
+/* time_util.c
+ *
+ * Wireshark - Network traffic analyzer
+ * By Gerald Combs <gerald@wireshark.org>
+ * Copyright 1998 Gerald Combs
+ *
+ * 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
+ * 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, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+
+
+#include "config.h"
+
+#include "time_util.h"
+
+/* converts a broken down date representation, relative to UTC,
+ * to a timestamp; it uses timegm() if it's available.
+ * Copied from Glib source gtimer.c
+ */
+time_t
+mktime_utc(struct tm *tm)
+{
+#ifndef HAVE_TIMEGM
+	time_t retval;
+
+	static const int days_before[] =
+		{
+			0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334
+		};
+
+	int yr;
+
+	if (tm->tm_mon < 0 || tm->tm_mon > 11)
+		return (time_t) -1;
+
+	retval = (tm->tm_year - 70) * 365;
+
+	/* count number of leap years */
+	yr  = tm->tm_year + 1900;
+	if (tm->tm_mon + 1 < 3 && (yr % 4) == 0 && ((yr % 100) != 0 || (yr % 400) == 0))
+		yr--;
+	retval += (((yr / 4) - (yr / 100) + (yr / 400)) - 477); /* 477 = ((1970 / 4) - (1970 / 100) + (1970 / 400)) */
+
+	retval += days_before[tm->tm_mon] + tm->tm_mday - 1;
+
+	retval = ((((retval * 24) + tm->tm_hour) * 60) + tm->tm_min) * 60 + tm->tm_sec;
+
+	return retval;
+#else
+	return timegm(tm);
+#endif /* !HAVE_TIMEGM */
+}