From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001
From: André Fabian Silva Delgado <emulatorman@parabola.nu>
Date: Wed, 5 Aug 2015 17:04:01 -0300
Subject: Initial import

---
 fs/ntfs/time.h | 100 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 100 insertions(+)
 create mode 100644 fs/ntfs/time.h

(limited to 'fs/ntfs/time.h')

diff --git a/fs/ntfs/time.h b/fs/ntfs/time.h
new file mode 100644
index 000000000..01233989d
--- /dev/null
+++ b/fs/ntfs/time.h
@@ -0,0 +1,100 @@
+/*
+ * time.h - NTFS time conversion functions.  Part of the Linux-NTFS project.
+ *
+ * Copyright (c) 2001-2005 Anton Altaparmakov
+ *
+ * This program/include file 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/include file 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 (in the main directory of the Linux-NTFS
+ * distribution in the file COPYING); if not, write to the Free Software
+ * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef _LINUX_NTFS_TIME_H
+#define _LINUX_NTFS_TIME_H
+
+#include <linux/time.h>		/* For current_kernel_time(). */
+#include <asm/div64.h>		/* For do_div(). */
+
+#include "endian.h"
+
+#define NTFS_TIME_OFFSET ((s64)(369 * 365 + 89) * 24 * 3600 * 10000000)
+
+/**
+ * utc2ntfs - convert Linux UTC time to NTFS time
+ * @ts:		Linux UTC time to convert to NTFS time
+ *
+ * Convert the Linux UTC time @ts to its corresponding NTFS time and return
+ * that in little endian format.
+ *
+ * Linux stores time in a struct timespec consisting of a time_t (long at
+ * present) tv_sec and a long tv_nsec where tv_sec is the number of 1-second
+ * intervals since 1st January 1970, 00:00:00 UTC and tv_nsec is the number of
+ * 1-nano-second intervals since the value of tv_sec.
+ *
+ * NTFS uses Microsoft's standard time format which is stored in a s64 and is
+ * measured as the number of 100-nano-second intervals since 1st January 1601,
+ * 00:00:00 UTC.
+ */
+static inline sle64 utc2ntfs(const struct timespec ts)
+{
+	/*
+	 * Convert the seconds to 100ns intervals, add the nano-seconds
+	 * converted to 100ns intervals, and then add the NTFS time offset.
+	 */
+	return cpu_to_sle64((s64)ts.tv_sec * 10000000 + ts.tv_nsec / 100 +
+			NTFS_TIME_OFFSET);
+}
+
+/**
+ * get_current_ntfs_time - get the current time in little endian NTFS format
+ *
+ * Get the current time from the Linux kernel, convert it to its corresponding
+ * NTFS time and return that in little endian format.
+ */
+static inline sle64 get_current_ntfs_time(void)
+{
+	return utc2ntfs(current_kernel_time());
+}
+
+/**
+ * ntfs2utc - convert NTFS time to Linux time
+ * @time:	NTFS time (little endian) to convert to Linux UTC
+ *
+ * Convert the little endian NTFS time @time to its corresponding Linux UTC
+ * time and return that in cpu format.
+ *
+ * Linux stores time in a struct timespec consisting of a time_t (long at
+ * present) tv_sec and a long tv_nsec where tv_sec is the number of 1-second
+ * intervals since 1st January 1970, 00:00:00 UTC and tv_nsec is the number of
+ * 1-nano-second intervals since the value of tv_sec.
+ *
+ * NTFS uses Microsoft's standard time format which is stored in a s64 and is
+ * measured as the number of 100 nano-second intervals since 1st January 1601,
+ * 00:00:00 UTC.
+ */
+static inline struct timespec ntfs2utc(const sle64 time)
+{
+	struct timespec ts;
+
+	/* Subtract the NTFS time offset. */
+	u64 t = (u64)(sle64_to_cpu(time) - NTFS_TIME_OFFSET);
+	/*
+	 * Convert the time to 1-second intervals and the remainder to
+	 * 1-nano-second intervals.
+	 */
+	ts.tv_nsec = do_div(t, 10000000) * 100;
+	ts.tv_sec = t;
+	return ts;
+}
+
+#endif /* _LINUX_NTFS_TIME_H */
-- 
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