1/*
 2 *  linux/fs/isofs/util.c
 3 */
 4
 5#include <linux/time.h>
 6#include "isofs.h"
 7
 8/* 
 9 * We have to convert from a MM/DD/YY format to the Unix ctime format.
10 * We have to take into account leap years and all of that good stuff.
11 * Unfortunately, the kernel does not have the information on hand to
12 * take into account daylight savings time, but it shouldn't matter.
13 * The time stored should be localtime (with or without DST in effect),
14 * and the timezone offset should hold the offset required to get back
15 * to GMT.  Thus  we should always be correct.
16 */
17
18int iso_date(char * p, int flag)
19{
20	int year, month, day, hour, minute, second, tz;
21	int crtime;
22
23	year = p[0];
24	month = p[1];
25	day = p[2];
26	hour = p[3];
27	minute = p[4];
28	second = p[5];
29	if (flag == 0) tz = p[6]; /* High sierra has no time zone */
30	else tz = 0;
31	
32	if (year < 0) {
33		crtime = 0;
34	} else {
35		crtime = mktime64(year+1900, month, day, hour, minute, second);
 
 
 
 
 
 
 
 
 
 
 
36
37		/* sign extend */
38		if (tz & 0x80)
39			tz |= (-1 << 8);
40		
41		/* 
42		 * The timezone offset is unreliable on some disks,
43		 * so we make a sanity check.  In no case is it ever
44		 * more than 13 hours from GMT, which is 52*15min.
45		 * The time is always stored in localtime with the
46		 * timezone offset being what get added to GMT to
47		 * get to localtime.  Thus we need to subtract the offset
48		 * to get to true GMT, which is what we store the time
49		 * as internally.  On the local system, the user may set
50		 * their timezone any way they wish, of course, so GMT
51		 * gets converted back to localtime on the receiving
52		 * system.
53		 *
54		 * NOTE: mkisofs in versions prior to mkisofs-1.10 had
55		 * the sign wrong on the timezone offset.  This has now
56		 * been corrected there too, but if you are getting screwy
57		 * results this may be the explanation.  If enough people
58		 * complain, a user configuration option could be added
59		 * to add the timezone offset in with the wrong sign
60		 * for 'compatibility' with older discs, but I cannot see how
61		 * it will matter that much.
62		 *
63		 * Thanks to kuhlmav@elec.canterbury.ac.nz (Volker Kuhlmann)
64		 * for pointing out the sign error.
65		 */
66		if (-52 <= tz && tz <= 52)
67			crtime -= tz * 15 * 60;
68	}
69	return crtime;
70}		

 1/*
 2 *  linux/fs/isofs/util.c
 3 */
 4
 
 5#include "isofs.h"
 6
 7/* 
 8 * We have to convert from a MM/DD/YY format to the Unix ctime format.
 9 * We have to take into account leap years and all of that good stuff.
10 * Unfortunately, the kernel does not have the information on hand to
11 * take into account daylight savings time, but it shouldn't matter.
12 * The time stored should be localtime (with or without DST in effect),
13 * and the timezone offset should hold the offset required to get back
14 * to GMT.  Thus  we should always be correct.
15 */
16
17int iso_date(char * p, int flag)
18{
19	int year, month, day, hour, minute, second, tz;
20	int crtime, days, i;
21
22	year = p[0] - 70;
23	month = p[1];
24	day = p[2];
25	hour = p[3];
26	minute = p[4];
27	second = p[5];
28	if (flag == 0) tz = p[6]; /* High sierra has no time zone */
29	else tz = 0;
30	
31	if (year < 0) {
32		crtime = 0;
33	} else {
34		int monlen[12] = {31,28,31,30,31,30,31,31,30,31,30,31};
35
36		days = year * 365;
37		if (year > 2)
38			days += (year+1) / 4;
39		for (i = 1; i < month; i++)
40			days += monlen[i-1];
41		if (((year+2) % 4) == 0 && month > 2)
42			days++;
43		days += day - 1;
44		crtime = ((((days * 24) + hour) * 60 + minute) * 60)
45			+ second;
46
47		/* sign extend */
48		if (tz & 0x80)
49			tz |= (-1 << 8);
50		
51		/* 
52		 * The timezone offset is unreliable on some disks,
53		 * so we make a sanity check.  In no case is it ever
54		 * more than 13 hours from GMT, which is 52*15min.
55		 * The time is always stored in localtime with the
56		 * timezone offset being what get added to GMT to
57		 * get to localtime.  Thus we need to subtract the offset
58		 * to get to true GMT, which is what we store the time
59		 * as internally.  On the local system, the user may set
60		 * their timezone any way they wish, of course, so GMT
61		 * gets converted back to localtime on the receiving
62		 * system.
63		 *
64		 * NOTE: mkisofs in versions prior to mkisofs-1.10 had
65		 * the sign wrong on the timezone offset.  This has now
66		 * been corrected there too, but if you are getting screwy
67		 * results this may be the explanation.  If enough people
68		 * complain, a user configuration option could be added
69		 * to add the timezone offset in with the wrong sign
70		 * for 'compatibility' with older discs, but I cannot see how
71		 * it will matter that much.
72		 *
73		 * Thanks to kuhlmav@elec.canterbury.ac.nz (Volker Kuhlmann)
74		 * for pointing out the sign error.
75		 */
76		if (-52 <= tz && tz <= 52)
77			crtime -= tz * 15 * 60;
78	}
79	return crtime;
80}