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author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 22:20:36 (GMT) |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 22:20:36 (GMT) |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /fs/isofs/util.c | |
download | linux-fsl-qoriq-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.xz |
Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'fs/isofs/util.c')
-rw-r--r-- | fs/isofs/util.c | 83 |
1 files changed, 83 insertions, 0 deletions
diff --git a/fs/isofs/util.c b/fs/isofs/util.c new file mode 100644 index 0000000..3f6d9c1 --- /dev/null +++ b/fs/isofs/util.c @@ -0,0 +1,83 @@ +/* + * linux/fs/isofs/util.c + */ + +#include <linux/time.h> +#include <linux/fs.h> +#include <linux/iso_fs.h> + +/* + * We have to convert from a MM/DD/YY format to the Unix ctime format. + * We have to take into account leap years and all of that good stuff. + * Unfortunately, the kernel does not have the information on hand to + * take into account daylight savings time, but it shouldn't matter. + * The time stored should be localtime (with or without DST in effect), + * and the timezone offset should hold the offset required to get back + * to GMT. Thus we should always be correct. + */ + +int iso_date(char * p, int flag) +{ + int year, month, day, hour, minute, second, tz; + int crtime, days, i; + + year = p[0] - 70; + month = p[1]; + day = p[2]; + hour = p[3]; + minute = p[4]; + second = p[5]; + if (flag == 0) tz = p[6]; /* High sierra has no time zone */ + else tz = 0; + + if (year < 0) { + crtime = 0; + } else { + int monlen[12] = {31,28,31,30,31,30,31,31,30,31,30,31}; + + days = year * 365; + if (year > 2) + days += (year+1) / 4; + for (i = 1; i < month; i++) + days += monlen[i-1]; + if (((year+2) % 4) == 0 && month > 2) + days++; + days += day - 1; + crtime = ((((days * 24) + hour) * 60 + minute) * 60) + + second; + + /* sign extend */ + if (tz & 0x80) + tz |= (-1 << 8); + + /* + * The timezone offset is unreliable on some disks, + * so we make a sanity check. In no case is it ever + * more than 13 hours from GMT, which is 52*15min. + * The time is always stored in localtime with the + * timezone offset being what get added to GMT to + * get to localtime. Thus we need to subtract the offset + * to get to true GMT, which is what we store the time + * as internally. On the local system, the user may set + * their timezone any way they wish, of course, so GMT + * gets converted back to localtime on the receiving + * system. + * + * NOTE: mkisofs in versions prior to mkisofs-1.10 had + * the sign wrong on the timezone offset. This has now + * been corrected there too, but if you are getting screwy + * results this may be the explanation. If enough people + * complain, a user configuration option could be added + * to add the timezone offset in with the wrong sign + * for 'compatibility' with older discs, but I cannot see how + * it will matter that much. + * + * Thanks to kuhlmav@elec.canterbury.ac.nz (Volker Kuhlmann) + * for pointing out the sign error. + */ + if (-52 <= tz && tz <= 52) + crtime -= tz * 15 * 60; + } + return crtime; +} + |