release/src/router/ntfs-3g/include/ntfs-3g/ntfstime.h

   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  * Copyright (c) 2010 Jean-Pierre Andre
   7  *
   8  * This program/include file is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License as published
  10  * by the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program/include file is distributed in the hope that it will be
  14  * useful, but WITHOUT ANY WARRANTY; without even the implied warranty
  15  * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program (in the main directory of the NTFS-3G
  20  * distribution in the file COPYING); if not, write to the Free Software
  21  * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  22  */
  23
  24 #ifndef _NTFS_NTFSTIME_H
  25 #define _NTFS_NTFSTIME_H
  26
  27 #ifdef HAVE_TIME_H
  28 #include <time.h>
  29 #endif
  30 #ifdef HAVE_SYS_STAT_H
  31 #include <sys/stat.h>
  32 #endif
  33 #ifdef HAVE_GETTIMEOFDAY
  34 #include <sys/time.h>
  35 #endif
  36
  37 #include "types.h"
  38
  39 /*
  40  * assume "struct timespec" is not defined if st_mtime is not defined
  41  */
  42 #ifndef st_mtime
  43 struct timespec {
  44         time_t tv_sec;
  45         long tv_nsec;
  46 } ;
  47 #endif
  48
  49 /*
  50  * There are four times more conversions of internal representation
  51  * to ntfs representation than any other conversion, so the most
  52  * efficient internal representation is ntfs representation
  53  * (with low endianness)
  54  */
  55 typedef sle64 ntfs_time;
  56
  57 #define NTFS_TIME_OFFSET ((s64)(369 * 365 + 89) * 24 * 3600 * 10000000)
  58
  59 /**
  60  * ntfs2timespec - Convert an NTFS time to Unix time
  61  * @ntfs_time:  An NTFS time in 100ns units since 1601
  62  *
  63  * NTFS stores times as the number of 100ns intervals since January 1st 1601 at
  64  * 00:00 UTC.  This system will not suffer from Y2K problems until ~57000AD.
  65  *
  66  * Return:  A Unix time (number of seconds since 1970, and nanoseconds)
  67  */
  68 static __inline__ struct timespec ntfs2timespec(ntfs_time ntfstime)
  69 {
  70         struct timespec spec;
  71         s64 cputime;
  72
  73         cputime = sle64_to_cpu(ntfstime);
  74         spec.tv_sec = (cputime - (NTFS_TIME_OFFSET)) / 10000000;
  75         spec.tv_nsec = (cputime - (NTFS_TIME_OFFSET)
  76                         - (s64)spec.tv_sec*10000000)*100;
  77                 /* force zero nsec for overflowing dates */
  78         if ((spec.tv_nsec < 0) || (spec.tv_nsec > 999999999))
  79                 spec.tv_nsec = 0;
  80         return (spec);
  81 }
  82
  83 /**
  84  * timespec2ntfs - Convert Linux time to NTFS time
  85  * @utc_time:  Linux time to convert to NTFS
  86  *
  87  * Convert the Linux time @utc_time to its corresponding NTFS time.
  88  *
  89  * Linux stores time in a long at present and measures it as the number of
  90  * 1-second intervals since 1st January 1970, 00:00:00 UTC
  91  * with a separated non-negative nanosecond value
  92  *
  93  * NTFS uses Microsoft's standard time format which is stored in a sle64 and is
  94  * measured as the number of 100 nano-second intervals since 1st January 1601,
  95  * 00:00:00 UTC.
  96  *
  97  * Return:  An NTFS time (100ns units since Jan 1601)
  98  */
  99 static __inline__ ntfs_time timespec2ntfs(struct timespec spec)
 100 {
 101         s64 units;
 102
 103         units = (s64)spec.tv_sec * 10000000
 104                                 + NTFS_TIME_OFFSET + spec.tv_nsec/100;
 105         return (cpu_to_le64(units));
 106 }
 107
 108 /*
 109  *              Return the current time in ntfs format
 110  */
 111
 112 static __inline__ ntfs_time ntfs_current_time(void)
 113 {
 114         struct timespec now;
 115
 116 #if defined(HAVE_CLOCK_GETTIME) || defined(HAVE_SYS_CLOCK_GETTIME)
 117         clock_gettime(CLOCK_REALTIME, &now);
 118 #elif defined(HAVE_GETTIMEOFDAY)
 119         struct timeval microseconds;
 120
 121         gettimeofday(&microseconds, (struct timezone*)NULL);
 122         now.tv_sec = microseconds.tv_sec;
 123         now.tv_nsec = microseconds.tv_usec*1000;
 124 #else
 125         now.tv_sec = time((time_t*)NULL);
 126         now.tv_nsec = 0;
 127 #endif
 128         return (timespec2ntfs(now));
 129 }
 130
 131 #endif /* _NTFS_NTFSTIME_H */