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
22 * to unix time
23 * 10/04/98: added new table-based lookup after seeing how ugly
24 * the gnu code is
25 * blf 09/27/99: ripped out all the old code and inserted new table from
26 * John Brockmeyer (without leap second corrections)
27 * rewrote udf_stamp_to_time and fixed timezone accounting in
28 * udf_time_to_stamp.
29 */
30
31 /*
32 * We don't take into account leap seconds. This may be correct or incorrect.
33 * For more NIST information (especially dealing with leap seconds), see:
34 * http://www.boulder.nist.gov/timefreq/pubs/bulletin/leapsecond.htm
35 */
36
37 #include "udfdecl.h"
38
39 #include <linux/types.h>
40 #include <linux/kernel.h>
41
42 #define EPOCH_YEAR 1970
43
44 #ifndef __isleap
45 /* Nonzero if YEAR is a leap year (every 4 years,
46 except every 100th isn't, and every 400th is). */
47 #define __isleap(year) \
48 ((year) % 4 == 0 && ((year) % 100 != 0 || (year) % 400 == 0))
49 #endif
50
51 /* How many days come before each month (0-12). */
52 static const unsigned short int __mon_yday[2][13] = {
53 /* Normal years. */
54 {0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365},
55 /* Leap years. */
56 {0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366}
57 };
58
59 #define MAX_YEAR_SECONDS 69
60 #define SPD 0x15180 /*3600*24 */
61 #define SPY(y, l, s) (SPD * (365 * y + l) + s)
62
63 static time_t year_seconds[MAX_YEAR_SECONDS] = {
64 /*1970*/ SPY(0, 0, 0), SPY(1, 0, 0), SPY(2, 0, 0), SPY(3, 1, 0),
65 /*1974*/ SPY(4, 1, 0), SPY(5, 1, 0), SPY(6, 1, 0), SPY(7, 2, 0),
66 /*1978*/ SPY(8, 2, 0), SPY(9, 2, 0), SPY(10, 2, 0), SPY(11, 3, 0),
67 /*1982*/ SPY(12, 3, 0), SPY(13, 3, 0), SPY(14, 3, 0), SPY(15, 4, 0),
68 /*1986*/ SPY(16, 4, 0), SPY(17, 4, 0), SPY(18, 4, 0), SPY(19, 5, 0),
69 /*1990*/ SPY(20, 5, 0), SPY(21, 5, 0), SPY(22, 5, 0), SPY(23, 6, 0),
70 /*1994*/ SPY(24, 6, 0), SPY(25, 6, 0), SPY(26, 6, 0), SPY(27, 7, 0),
71 /*1998*/ SPY(28, 7, 0), SPY(29, 7, 0), SPY(30, 7, 0), SPY(31, 8, 0),
72 /*2002*/ SPY(32, 8, 0), SPY(33, 8, 0), SPY(34, 8, 0), SPY(35, 9, 0),
73 /*2006*/ SPY(36, 9, 0), SPY(37, 9, 0), SPY(38, 9, 0), SPY(39, 10, 0),
74 /*2010*/ SPY(40, 10, 0), SPY(41, 10, 0), SPY(42, 10, 0), SPY(43, 11, 0),
75 /*2014*/ SPY(44, 11, 0), SPY(45, 11, 0), SPY(46, 11, 0), SPY(47, 12, 0),
76 /*2018*/ SPY(48, 12, 0), SPY(49, 12, 0), SPY(50, 12, 0), SPY(51, 13, 0),
77 /*2022*/ SPY(52, 13, 0), SPY(53, 13, 0), SPY(54, 13, 0), SPY(55, 14, 0),
78 /*2026*/ SPY(56, 14, 0), SPY(57, 14, 0), SPY(58, 14, 0), SPY(59, 15, 0),
79 /*2030*/ SPY(60, 15, 0), SPY(61, 15, 0), SPY(62, 15, 0), SPY(63, 16, 0),
80 /*2034*/ SPY(64, 16, 0), SPY(65, 16, 0), SPY(66, 16, 0), SPY(67, 17, 0),
81 /*2038*/ SPY(68, 17, 0)
82 };
83
84 extern struct timezone sys_tz;
85
86 #define SECS_PER_HOUR (60 * 60)
87 #define SECS_PER_DAY (SECS_PER_HOUR * 24)
88
89 struct timespec *
udf_disk_stamp_to_time(struct timespec * dest,struct timestamp src)90 udf_disk_stamp_to_time(struct timespec *dest, struct timestamp src)
91 {
92 int yday;
93 u16 typeAndTimezone = le16_to_cpu(src.typeAndTimezone);
94 u16 year = le16_to_cpu(src.year);
95 uint8_t type = typeAndTimezone >> 12;
96 int16_t offset;
97
98 if (type == 1) {
99 offset = typeAndTimezone << 4;
100 /* sign extent offset */
101 offset = (offset >> 4);
102 if (offset == -2047) /* unspecified offset */
103 offset = 0;
104 } else
105 offset = 0;
106
107 if ((year < EPOCH_YEAR) ||
108 (year >= EPOCH_YEAR + MAX_YEAR_SECONDS)) {
109 return NULL;
110 }
111 dest->tv_sec = year_seconds[year - EPOCH_YEAR];
112 dest->tv_sec -= offset * 60;
113
114 yday = ((__mon_yday[__isleap(year)][src.month - 1]) + src.day - 1);
115 dest->tv_sec += (((yday * 24) + src.hour) * 60 + src.minute) * 60 + src.second;
116 dest->tv_nsec = 1000 * (src.centiseconds * 10000 +
117 src.hundredsOfMicroseconds * 100 + src.microseconds);
118 return dest;
119 }
120
121 struct timestamp *
udf_time_to_disk_stamp(struct timestamp * dest,struct timespec ts)122 udf_time_to_disk_stamp(struct timestamp *dest, struct timespec ts)
123 {
124 long int days, rem, y;
125 const unsigned short int *ip;
126 int16_t offset;
127
128 offset = -sys_tz.tz_minuteswest;
129
130 if (!dest)
131 return NULL;
132
133 dest->typeAndTimezone = cpu_to_le16(0x1000 | (offset & 0x0FFF));
134
135 ts.tv_sec += offset * 60;
136 days = ts.tv_sec / SECS_PER_DAY;
137 rem = ts.tv_sec % SECS_PER_DAY;
138 dest->hour = rem / SECS_PER_HOUR;
139 rem %= SECS_PER_HOUR;
140 dest->minute = rem / 60;
141 dest->second = rem % 60;
142 y = 1970;
143
144 #define DIV(a, b) ((a) / (b) - ((a) % (b) < 0))
145 #define LEAPS_THRU_END_OF(y) (DIV (y, 4) - DIV (y, 100) + DIV (y, 400))
146
147 while (days < 0 || days >= (__isleap(y) ? 366 : 365)) {
148 long int yg = y + days / 365 - (days % 365 < 0);
149
150 /* Adjust DAYS and Y to match the guessed year. */
151 days -= ((yg - y) * 365
152 + LEAPS_THRU_END_OF(yg - 1)
153 - LEAPS_THRU_END_OF(y - 1));
154 y = yg;
155 }
156 dest->year = cpu_to_le16(y);
157 ip = __mon_yday[__isleap(y)];
158 for (y = 11; days < (long int)ip[y]; --y)
159 continue;
160 days -= ip[y];
161 dest->month = y + 1;
162 dest->day = days + 1;
163
164 dest->centiseconds = ts.tv_nsec / 10000000;
165 dest->hundredsOfMicroseconds = (ts.tv_nsec / 1000 -
166 dest->centiseconds * 10000) / 100;
167 dest->microseconds = (ts.tv_nsec / 1000 - dest->centiseconds * 10000 -
168 dest->hundredsOfMicroseconds * 100);
169 return dest;
170 }
171
172 /* EOF */
173