aboutsummaryrefslogtreecommitdiff
path: root/fs/udf/udftime.c
blob: c2634bda6b5030419d51b71e062b92e28addf8ee (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
/* Copyright (C) 1993, 1994, 1995, 1996, 1997 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Paul Eggert (eggert@twinsun.com).

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public License as
   published by the Free Software Foundation; either version 2 of the
   License, or (at your option) any later version.

   The GNU C Library 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
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public
   License along with the GNU C Library; see the file COPYING.LIB.  If not,
   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.  */

/*
 * dgb 10/02/98: ripped this from glibc source to help convert timestamps to unix time 
 *     10/04/98: added new table-based lookup after seeing how ugly the gnu code is
 * blf 09/27/99: ripped out all the old code and inserted new table from
 *					John Brockmeyer (without leap second corrections)
 *				 rewrote udf_stamp_to_time and fixed timezone accounting in
					udf_time_to_stamp.
 */

/*
 * We don't take into account leap seconds. This may be correct or incorrect.
 * For more NIST information (especially dealing with leap seconds), see:
 *  http://www.boulder.nist.gov/timefreq/pubs/bulletin/leapsecond.htm
 */

#include <linux/types.h>
#include <linux/kernel.h>
#include "udfdecl.h"

#define EPOCH_YEAR 1970

#ifndef __isleap
/* Nonzero if YEAR is a leap year (every 4 years,
   except every 100th isn't, and every 400th is).  */
#define	__isleap(year)	\
  ((year) % 4 == 0 && ((year) % 100 != 0 || (year) % 400 == 0))
#endif

/* How many days come before each month (0-12).  */
const unsigned short int __mon_yday[2][13] =
{
	/* Normal years.  */
	{ 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 },
	/* Leap years.  */
	{ 0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366 }
};

#define MAX_YEAR_SECONDS	69
#define SPD 0x15180 /*3600*24*/
#define SPY(y,l,s) (SPD * (365*y+l)+s)

static time_t year_seconds[MAX_YEAR_SECONDS]= {
/*1970*/ SPY( 0, 0,0), SPY( 1, 0,0), SPY( 2, 0,0), SPY( 3, 1,0), 
/*1974*/ SPY( 4, 1,0), SPY( 5, 1,0), SPY( 6, 1,0), SPY( 7, 2,0), 
/*1978*/ SPY( 8, 2,0), SPY( 9, 2,0), SPY(10, 2,0), SPY(11, 3,0), 
/*1982*/ SPY(12, 3,0), SPY(13, 3,0), SPY(14, 3,0), SPY(15, 4,0), 
/*1986*/ SPY(16, 4,0), SPY(17, 4,0), SPY(18, 4,0), SPY(19, 5,0), 
/*1990*/ SPY(20, 5,0), SPY(21, 5,0), SPY(22, 5,0), SPY(23, 6,0), 
/*1994*/ SPY(24, 6,0), SPY(25, 6,0), SPY(26, 6,0), SPY(27, 7,0), 
/*1998*/ SPY(28, 7,0), SPY(29, 7,0), SPY(30, 7,0), SPY(31, 8,0), 
/*2002*/ SPY(32, 8,0), SPY(33, 8,0), SPY(34, 8,0), SPY(35, 9,0), 
/*2006*/ SPY(36, 9,0), SPY(37, 9,0), SPY(38, 9,0), SPY(39,10,0), 
/*2010*/ SPY(40,10,0), SPY(41,10,0), SPY(42,10,0), SPY(43,11,0), 
/*2014*/ SPY(44,11,0), SPY(45,11,0), SPY(46,11,0), SPY(47,12,0), 
/*2018*/ SPY(48,12,0), SPY(49,12,0), SPY(50,12,0), SPY(51,13,0), 
/*2022*/ SPY(52,13,0), SPY(53,13,0), SPY(54,13,0), SPY(55,14,0), 
/*2026*/ SPY(56,14,0), SPY(57,14,0), SPY(58,14,0), SPY(59,15,0), 
/*2030*/ SPY(60,15,0), SPY(61,15,0), SPY(62,15,0), SPY(63,16,0), 
/*2034*/ SPY(64,16,0), SPY(65,16,0), SPY(66,16,0), SPY(67,17,0), 
/*2038*/ SPY(68,17,0)
};

extern struct timezone sys_tz;

#define SECS_PER_HOUR	(60 * 60)
#define SECS_PER_DAY	(SECS_PER_HOUR * 24)

time_t *
udf_stamp_to_time(time_t *dest, long *dest_usec, kernel_timestamp src)
{
	int yday;
	uint8_t type = src.typeAndTimezone >> 12;
	int16_t offset;

	if (type == 1)
	{
		offset = src.typeAndTimezone << 4;
		/* sign extent offset */
		offset = (offset >> 4);
		if (offset == -2047) /* unspecified offset */
			offset = 0;
	}
	else
		offset = 0;

	if ((src.year < EPOCH_YEAR) ||
		(src.year > EPOCH_YEAR+MAX_YEAR_SECONDS))
	{
		*dest = -1;
		*dest_usec = -1;
		return NULL;
	}
	*dest = year_seconds[src.year - EPOCH_YEAR];
	*dest -= offset * 60;

	yday = ((__mon_yday[__isleap (src.year)]
		[src.month-1]) + (src.day-1));
	*dest += ( ( (yday* 24) + src.hour ) * 60 + src.minute ) * 60 + src.second;
	*dest_usec = src.centiseconds * 10000 + src.hundredsOfMicroseconds * 100 + src.microseconds;
	return dest;
}


kernel_timestamp *
udf_time_to_stamp(kernel_timestamp *dest, struct timespec ts)
{
	long int days, rem, y;
	const unsigned short int *ip;
	int16_t offset;

	offset = -sys_tz.tz_minuteswest;

	if (!dest)
		return NULL;

	dest->typeAndTimezone = 0x1000 | (offset & 0x0FFF);

	ts.tv_sec += offset * 60;
	days = ts.tv_sec / SECS_PER_DAY;
	rem = ts.tv_sec % SECS_PER_DAY;
	dest->hour = rem / SECS_PER_HOUR;
	rem %= SECS_PER_HOUR;
	dest->minute = rem / 60;
	dest->second = rem % 60;
	y = 1970;

#define DIV(a,b) ((a) / (b) - ((a) % (b) < 0))
#define LEAPS_THRU_END_OF(y) (DIV (y, 4) - DIV (y, 100) + DIV (y, 400))

	while (days < 0 || days >= (__isleap(y) ? 366 : 365))
	{
		long int yg = y + days / 365 - (days % 365 < 0);

		/* Adjust DAYS and Y to match the guessed year.  */
		days -= ((yg - y) * 365
			+ LEAPS_THRU_END_OF (yg - 1)
			- LEAPS_THRU_END_OF (y - 1));
		y = yg;
	}
	dest->year = y;
	ip = __mon_yday[__isleap(y)];
	for (y = 11; days < (long int) ip[y]; --y)
		continue;
	days -= ip[y];
	dest->month = y + 1;
	dest->day = days + 1;

	dest->centiseconds = ts.tv_nsec / 10000000;
	dest->hundredsOfMicroseconds = (ts.tv_nsec / 1000 - dest->centiseconds * 10000) / 100;
	dest->microseconds = (ts.tv_nsec / 1000 - dest->centiseconds * 10000 -
		dest->hundredsOfMicroseconds * 100);
	return dest;
}

/* EOF */