1 /* 2 * ntfstime.h - NTFS time related functions. Originated from the Linux-NTFS project. 3 * 4 * Copyright (c) 2005 Anton Altaparmakov 5 * Copyright (c) 2005 Yura Pakhuchiy 6 * 7 * This program/include file is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU General Public License as published 9 * by the Free Software Foundation; either version 2 of the License, or 10 * (at your option) any later version. 11 * 12 * This program/include file is distributed in the hope that it will be 13 * useful, but WITHOUT ANY WARRANTY; without even the implied warranty 14 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 * GNU General Public License for more details. 16 * 17 * You should have received a copy of the GNU General Public License 18 * along with this program (in the main directory of the NTFS-3G 19 * distribution in the file COPYING); if not, write to the Free Software 20 * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 21 */ 22 23 #ifndef _NTFS_NTFSTIME_H 24 #define _NTFS_NTFSTIME_H 25 26 #ifdef HAVE_TIME_H 27 #include <time.h> 28 #endif 29 30 #include "types.h" 31 32 #define NTFS_TIME_OFFSET ((s64)(369 * 365 + 89) * 24 * 3600 * 10000000) 33 34 /** 35 * ntfs2utc - Convert an NTFS time to Unix time 36 * @ntfs_time: An NTFS time in 100ns units since 1601 37 * 38 * NTFS stores times as the number of 100ns intervals since January 1st 1601 at 39 * 00:00 UTC. This system will not suffer from Y2K problems until ~57000AD. 40 * 41 * Return: n A Unix time (number of seconds since 1970) 42 */ 43 static __inline__ time_t ntfs2utc(s64 ntfs_time) 44 { 45 return (sle64_to_cpu(ntfs_time) - (NTFS_TIME_OFFSET)) / 10000000; 46 } 47 48 /** 49 * utc2ntfs - Convert Linux time to NTFS time 50 * @utc_time: Linux time to convert to NTFS 51 * 52 * Convert the Linux time @utc_time to its corresponding NTFS time. 53 * 54 * Linux stores time in a long at present and measures it as the number of 55 * 1-second intervals since 1st January 1970, 00:00:00 UTC. 56 * 57 * NTFS uses Microsoft's standard time format which is stored in a s64 and is 58 * measured as the number of 100 nano-second intervals since 1st January 1601, 59 * 00:00:00 UTC. 60 * 61 * Return: n An NTFS time (100ns units since Jan 1601) 62 */ 63 static __inline__ s64 utc2ntfs(time_t utc_time) 64 { 65 /* Convert to 100ns intervals and then add the NTFS time offset. */ 66 return cpu_to_sle64((s64)utc_time * 10000000 + NTFS_TIME_OFFSET); 67 } 68 69 #endif /* _NTFS_NTFSTIME_H */ 70