fs/udf/udftime.c

   1 /* Copyright (C) 1993, 1994, 1995, 1996, 1997 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Paul Eggert (eggert@twinsun.com).
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Library General Public License as
   7    published by the Free Software Foundation; either version 2 of the
   8    License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Library General Public License for more details.
  14
  15    You should have received a copy of the GNU Library General Public
  16    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  17    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18    Boston, MA 02111-1307, USA.  */
  19
  20 /*
  21  * dgb 10/02/98: ripped this from glibc source to help convert timestamps to unix time
  22  *     10/04/98: added new table-based lookup after seeing how ugly the gnu code is
  23  * blf 09/27/99: ripped out all the old code and inserted new table from
  24  *               John Brockmeyer (without leap second corrections)
  25  *               rewrote udf_stamp_to_time and fixed timezone accounting in
  26  *               udf_time_to_stamp.
  27  */
  28
  29 /*
  30  * We don't take into account leap seconds. This may be correct or incorrect.
  31  * For more NIST information (especially dealing with leap seconds), see:
  32  * http://www.boulder.nist.gov/timefreq/pubs/bulletin/leapsecond.htm
  33  */
  34
  35 #include <linux/types.h>
  36 #include <linux/kernel.h>
  37 #include "udfdecl.h"
  38
  39 #define EPOCH_YEAR 1970
  40
  41 #ifndef __isleap
  42 /* Nonzero if YEAR is a leap year (every 4 years,
  43    except every 100th isn't, and every 400th is).  */
  44 #define __isleap(year)  \
  45   ((year) % 4 == 0 && ((year) % 100 != 0 || (year) % 400 == 0))
  46 #endif
  47
  48 /* How many days come before each month (0-12).  */
  49 static const unsigned short int __mon_yday[2][13] = {
  50         /* Normal years.  */
  51         {0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365},
  52         /* Leap years.  */
  53         {0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366}
  54 };
  55
  56 #define MAX_YEAR_SECONDS        69
  57 #define SPD                     0x15180 /*3600*24 */
  58 #define SPY(y,l,s)              (SPD * (365*y+l)+s)
  59
  60 static time_t year_seconds[MAX_YEAR_SECONDS]= {
  61 /*1970*/ SPY( 0, 0,0), SPY( 1, 0,0), SPY( 2, 0,0), SPY( 3, 1,0),
  62 /*1974*/ SPY( 4, 1,0), SPY( 5, 1,0), SPY( 6, 1,0), SPY( 7, 2,0),
  63 /*1978*/ SPY( 8, 2,0), SPY( 9, 2,0), SPY(10, 2,0), SPY(11, 3,0),
  64 /*1982*/ SPY(12, 3,0), SPY(13, 3,0), SPY(14, 3,0), SPY(15, 4,0),
  65 /*1986*/ SPY(16, 4,0), SPY(17, 4,0), SPY(18, 4,0), SPY(19, 5,0),
  66 /*1990*/ SPY(20, 5,0), SPY(21, 5,0), SPY(22, 5,0), SPY(23, 6,0),
  67 /*1994*/ SPY(24, 6,0), SPY(25, 6,0), SPY(26, 6,0), SPY(27, 7,0),
  68 /*1998*/ SPY(28, 7,0), SPY(29, 7,0), SPY(30, 7,0), SPY(31, 8,0),
  69 /*2002*/ SPY(32, 8,0), SPY(33, 8,0), SPY(34, 8,0), SPY(35, 9,0),
  70 /*2006*/ SPY(36, 9,0), SPY(37, 9,0), SPY(38, 9,0), SPY(39,10,0),
  71 /*2010*/ SPY(40,10,0), SPY(41,10,0), SPY(42,10,0), SPY(43,11,0),
  72 /*2014*/ SPY(44,11,0), SPY(45,11,0), SPY(46,11,0), SPY(47,12,0),
  73 /*2018*/ SPY(48,12,0), SPY(49,12,0), SPY(50,12,0), SPY(51,13,0),
  74 /*2022*/ SPY(52,13,0), SPY(53,13,0), SPY(54,13,0), SPY(55,14,0),
  75 /*2026*/ SPY(56,14,0), SPY(57,14,0), SPY(58,14,0), SPY(59,15,0),
  76 /*2030*/ SPY(60,15,0), SPY(61,15,0), SPY(62,15,0), SPY(63,16,0),
  77 /*2034*/ SPY(64,16,0), SPY(65,16,0), SPY(66,16,0), SPY(67,17,0),
  78 /*2038*/ SPY(68,17,0)
  79 };
  80
  81 extern struct timezone sys_tz;
  82
  83 #define SECS_PER_HOUR   (60 * 60)
  84 #define SECS_PER_DAY    (SECS_PER_HOUR * 24)
  85
  86 time_t *udf_stamp_to_time(time_t *dest, long *dest_usec, kernel_timestamp src)
  87 {
  88         int yday;
  89         uint8_t type = src.typeAndTimezone >> 12;
  90         int16_t offset;
  91
  92         if (type == 1) {
  93                 offset = src.typeAndTimezone << 4;
  94                 /* sign extent offset */
  95                 offset = (offset >> 4);
  96                 if (offset == -2047) /* unspecified offset */
  97                         offset = 0;
  98         } else {
  99                 offset = 0;
 100         }
 101
 102         if ((src.year < EPOCH_YEAR) ||
 103             (src.year >= EPOCH_YEAR + MAX_YEAR_SECONDS)) {
 104                 *dest = -1;
 105                 *dest_usec = -1;
 106                 return NULL;
 107         }
 108         *dest = year_seconds[src.year - EPOCH_YEAR];
 109         *dest -= offset * 60;
 110
 111         yday = ((__mon_yday[__isleap(src.year)][src.month - 1]) + src.day - 1);
 112         *dest += (((yday * 24) + src.hour) * 60 + src.minute) * 60 + src.second;
 113         *dest_usec = src.centiseconds * 10000 +
 114                         src.hundredsOfMicroseconds * 100 + src.microseconds;
 115         return dest;
 116 }
 117
 118 kernel_timestamp *udf_time_to_stamp(kernel_timestamp * dest, struct timespec ts)
 119 {
 120         long int days, rem, y;
 121         const unsigned short int *ip;
 122         int16_t offset;
 123
 124         offset = -sys_tz.tz_minuteswest;
 125
 126         if (!dest)
 127                 return NULL;
 128
 129         dest->typeAndTimezone = 0x1000 | (offset & 0x0FFF);
 130
 131         ts.tv_sec += offset * 60;
 132         days = ts.tv_sec / SECS_PER_DAY;
 133         rem = ts.tv_sec % SECS_PER_DAY;
 134         dest->hour = rem / SECS_PER_HOUR;
 135         rem %= SECS_PER_HOUR;
 136         dest->minute = rem / 60;
 137         dest->second = rem % 60;
 138         y = 1970;
 139
 140 #define DIV(a,b) ((a) / (b) - ((a) % (b) < 0))
 141 #define LEAPS_THRU_END_OF(y) (DIV (y, 4) - DIV (y, 100) + DIV (y, 400))
 142
 143         while (days < 0 || days >= (__isleap(y) ? 366 : 365)) {
 144                 long int yg = y + days / 365 - (days % 365 < 0);
 145
 146                 /* Adjust DAYS and Y to match the guessed year.  */
 147                 days -= ((yg - y) * 365
 148                          + LEAPS_THRU_END_OF (yg - 1)
 149                          - LEAPS_THRU_END_OF (y - 1));
 150                 y = yg;
 151         }
 152         dest->year = y;
 153         ip = __mon_yday[__isleap(y)];
 154         for (y = 11; days < (long int)ip[y]; --y)
 155                 continue;
 156         days -= ip[y];
 157         dest->month = y + 1;
 158         dest->day = days + 1;
 159
 160         dest->centiseconds = ts.tv_nsec / 10000000;
 161         dest->hundredsOfMicroseconds = (ts.tv_nsec / 1000 - dest->centiseconds * 10000) / 100;
 162         dest->microseconds = (ts.tv_nsec / 1000 - dest->centiseconds * 10000 -
 163                               dest->hundredsOfMicroseconds * 100);
 164         return dest;
 165 }
 166
 167 /* EOF */