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From: Brian Inglis <Brian.Inglis@SystematicSW.ab.ca>
To: cygwin@cygwin.com
Subject: Re: tzdata bug?
Date: Wed, 17 Apr 2024 23:30:07 -0600	[thread overview]
Message-ID: <f370bc33-731e-4bbe-ab59-aa694a63f53b@SystematicSW.ab.ca> (raw)
In-Reply-To: <36001589.119195.1713339202522@mail.yahoo.com>

On 2024-04-17 01:33, alf salte via Cygwin wrote:
> The man 5 tzfile page says that data should be in big endian format but when I inspect a tzfile on my system it seems that the second part with 8 byte integers are in little endian format rather than the big endian that the man page says it should be.
> Is this intentional or is it a bug?

What are you using to inspect the file?
If you are using vim's xxd, remember that it defaults to big-endian format!
If you check 0x2c bytes after 2nd TZif# header, many files will have entries 
ffffffffxxxxxxxx in increasing order to 00000000xxxxxxxx; for example:

$ xxd -s 0x537 -l 0x2c -g4 /usr/share/zoneinfo/Europe/London
00000537: 545a6966 32000000 00000000 00000000  TZif2...........
00000547: 00000000 00000008 00000008 00000000  ................
00000557: 000000f2 00000008 00000011           ............
$ xxd -s 0x563 -l 0x790 -g8 /usr/share/zoneinfo/Europe/London
00000563: ffffffff1a5d09cb ffffffff9b26ada0  .....].......&..
00000573: ffffffff9bd60520 ffffffff9ccf30a0  ....... ......0.
00000583: ffffffff9da4c3a0 ffffffff9e9c9da0  ................
00000593: ffffffff9f971aa0 ffffffffa085ba20  ...............
000005a3: ffffffffa176fca0 ffffffffa2659c20  .....v.......e.
000005b3: ffffffffa37bc8a0 ffffffffa44eb8a0  .....{.......N..
000005c3: ffffffffa53ffb20 ffffffffa6256020  .....?. .....%`
000005d3: ffffffffa727c620 ffffffffa82a2c20  .....'. .....*,
000005e3: ffffffffa8ebf8a0 ffffffffaa00d3a0  ................
000005f3: ffffffffaad51520 ffffffffabe9f020  ....... .......
00000603: ffffffffacc76c20 ffffffffadc9d220  ......l .......
00000613: ffffffffaea74e20 ffffffffafa079a0  ......N ......y.
00000623: ffffffffb0873020 ffffffffb192d0a0  ......0 ........
00000633: ffffffffb2704ca0 ffffffffb372b2a0  .....pL......r..
00000643: ffffffffb4502ea0 ffffffffb5495a20  .....P.......IZ
00000653: ffffffffb63010a0 ffffffffb73276a0  .....0.......2v.
00000663: ffffffffb80ff2a0 ffffffffb91258a0  ..............X.
00000673: ffffffffb9efd4a0 ffffffffbae90020  ...............
00000683: ffffffffbbd8f120 ffffffffbcdb5720  ....... ......W
00000693: ffffffffbdb8d320 ffffffffbeb1fea0  ....... ........
000006a3: ffffffffbf98b520 ffffffffc09b1b20  ....... .......
000006b3: ffffffffc1789720 ffffffffc27afd20  .....x. .....z.
000006c3: ffffffffc3587920 ffffffffc451a4a0  .....Xy .....Q..
000006d3: ffffffffc5385b20 ffffffffc63ac120  .....8[ .....:.
000006e3: ffffffffc758d6a0 ffffffffc7da09a0  .....X..........
000006f3: ffffffffca162690 ffffffffca975990  ......&.......Y.
00000703: ffffffffcbd11e90 ffffffffcc773b90  .............w;.
00000713: ffffffffcdb10090 ffffffffce605810  .............`X.
00000723: ffffffffcf90e290 ffffffffd06e5e90  .............n^.
00000733: ffffffffd1721610 ffffffffd1fb3210  .....r........2.
00000743: ffffffffd269fe20 ffffffffd36329a0  .....i. .....c).
00000753: ffffffffd449e020 ffffffffd51e21a0  .....I. ......!.
00000763: ffffffffd542fd90 ffffffffd5dfe010  .....B..........
00000773: ffffffffd64eac20 ffffffffd6fe03a0  .....N. ........
00000783: ffffffffd82e8e20 ffffffffd8f99520  ....... .......
00000793: ffffffffda0e7020 ffffffffdaebec20  ......p .......
000007a3: ffffffffdbe517a0 ffffffffdccbce20  ...............
000007b3: ffffffffddc4f9a0 ffffffffdeb4eaa0  ................
000007c3: ffffffffdfae1620 ffffffffe094cca0  ....... ........
000007d3: ffffffffe17248a0 ffffffffe26b7420  .....rH......kt
000007e3: ffffffffe3522aa0 ffffffffe45490a0  .....R*......T..
000007f3: ffffffffe5320ca0 ffffffffe63dad20  .....2.......=.
00000803: ffffffffe71b2920 ffffffffe81454a0  ......) ......T.
00000813: ffffffffe8fb0b20 ffffffffe9fd7120  ....... ......q
00000823: ffffffffeadaed20 ffffffffebdd5320  ....... ......S
00000833: ffffffffecbacf20 ffffffffedb3faa0  ....... ........
00000843: ffffffffee9ab120 ffffffffef8167a0  ....... ......g.
00000853: fffffffff09f7d20 fffffffff16149a0  ......} .....aI.
00000863: fffffffff27f5f20 fffffffff34a6620  ......_ .....Jf
00000873: fffffffff45f4120 fffffffff5210da0  ....._A .....!..
00000883: fffffffff63f2320 fffffffff700efa0  .....?# ........
00000893: fffffffff81f0520 fffffffff8e0d1a0  ....... ........
000008a3: fffffffff9fee720 fffffffffac0b3a0  ....... ........
000008b3: fffffffffbe803a0 fffffffffc7baba0  .............{..
000008c3: fffffffffdc7bb70 000000000370c620  .......p.....p.
000008d3: 0000000004295820 000000000550a820  .....)X .....P.
000008e3: 0000000006093a20 0000000007308a20  ......: .....0.
000008f3: 0000000007e91c20 0000000009106c20  ....... ......l
00000903: 0000000009c8fe20 000000000af04e20  ....... ......N
00000913: 000000000bb21aa0 000000000cd03020  ..............0
00000923: 000000000d91fca0 000000000eb01220  ...............
00000933: 000000000f71dea0 0000000010992ea0  .....q..........
00000943: 000000001151c0a0 00000000127910a0  .....Q.......y..
00000953: 000000001331a2a0 000000001458f2a0  .....1.......X..
00000963: 000000001523eb90 000000001638c690  .....#.......8..
00000973: 000000001703cd90 000000001818a890  ................
00000983: 0000000018e3af90 0000000019f88a90  ................
00000993: 000000001ac39190 000000001be1a710  ................
000009a3: 000000001cacae10 000000001dc18910  ................
000009b3: 000000001e8c9010 000000001fa16b10  ..............k.
000009c3: 00000000206c7210 0000000021814d10  .... lr.....!.M.
000009d3: 00000000224c5410 0000000023612f10  ...."LT.....#a/.
000009e3: 00000000242c3610 00000000254a4b90  ....$,6.....%JK.
000009f3: 00000000260c1810 00000000272a2d90  ....&.......'*-.
00000a03: 0000000027f53490 00000000290a0f90  ....'.4.....)...
00000a13: 0000000029d51690 000000002ae9f190  ....).......*...
00000a23: 000000002bb4f890 000000002cc9d390  ....+.......,...
00000a33: 000000002d94da90 000000002ea9b590  ....-...........
00000a43: 000000002f74bc90 0000000030899790  ..../t......0...
00000a53: 00000000315dd910 000000003272b410  ....1]......2r..
00000a63: 00000000333dbb10 0000000034529610  ....3=......4R..
00000a73: 00000000351d9d10 0000000036327810  ....5.......62x.
00000a83: 0000000036fd7f10 00000000381b9490  ....6.......8...
00000a93: 0000000038dd6110 0000000039fb7690  ....8.a.....9.v.
00000aa3: 000000003abd4310 000000003bdb5890  ....:.C.....;.X.
00000ab3: 000000003ca65f90 000000003dbb3a90  ....<._.....=.:.
00000ac3: 000000003e864190 000000003f9b1c90  ....>.A.....?...
00000ad3: 0000000040662390 0000000041843910  ....@f#.....A.9.
00000ae3: 0000000042460590 0000000043641b10  ....BF......Cd..
00000af3: 000000004425e790 000000004543fd10  ....D%......EC..
00000b03: 000000004605c990 000000004723df10  ....F.......G#..
00000b13: 0000000047eee610 000000004903c110  ....G.......I...
00000b23: 0000000049cec810 000000004ae3a310  ....I.......J...
00000b33: 000000004baeaa10 000000004cccbf90  ....K.......L...
00000b43: 000000004d8e8c10 000000004eaca190  ....M.......N...
00000b53: 000000004f6e6e10 00000000508c8390  ....Onn.....P...
00000b63: 0000000051578a90 00000000526c6590  ....QW......Rle.
00000b73: 0000000053376c90 00000000544c4790  ....S7l.....TLG.
00000b83: 0000000055174e90 00000000562c2990  ....U.N.....V,).
00000b93: 0000000056f73090 0000000058154610  ....V.0.....X.F.
00000ba3: 0000000058d71290 0000000059f52810  ....X.......Y.(.
00000bb3: 000000005ab6f490 000000005bd50a10  ....Z.......[...
00000bc3: 000000005ca01110 000000005db4ec10  ....\.......]...
00000bd3: 000000005e7ff310 000000005f94ce10  ....^......._...
00000be3: 00000000605fd510 00000000617dea90  ....`_......a}..
00000bf3: 00000000623fb710 00000000635dcc90  ....b?......c]..
00000c03: 00000000641f9910 00000000653dae90  ....d.......e=..
00000c13: 000000006608b590 00000000671d9090  ....f.......g...
00000c23: 0000000067e89790 0000000068fd7290  ....g.......h.r.
00000c33: 0000000069c87990 000000006add5490  ....i.y.....j.T.
00000c43: 000000006ba85b90 000000006cc67110  ....k.[.....l.q.
00000c53: 000000006d883d90 000000006ea65310  ....m.=.....n.S.
00000c63: 000000006f681f90 0000000070863510  ....oh......p.5.
00000c73: 0000000071513c10 0000000072661710  ....qQ<.....rf..
00000c83: 0000000073311e10 000000007445f910  ....s1......tE..
00000c93: 0000000075110010 00000000762f1590  ....u.......v/..
00000ca3: 0000000076f0e210 00000000780ef790  ....v.......x...
00000cb3: 0000000078d0c410 0000000079eed990  ....x.......y...
00000cc3: 000000007ab0a610 000000007bcebb90  ....z.......{...
00000cd3: 000000007c99c290 000000007dae9d90  ....|.......}...
00000ce3: 000000007e79a490 000000007f8e7f90  ....~y..........
$ xxd -s 0xcf3 -l 0xf2 -g1 /usr/share/zoneinfo/Europe/London
00000cf3: 04 01 02 01 02 01 02 01 02 01 02 01 02 01 02 01  ................
00000d03: 02 01 02 01 02 01 02 01 02 01 02 01 02 01 02 01  ................
00000d13: 02 01 02 01 02 01 02 01 02 01 02 01 02 01 02 01  ................
00000d23: 02 01 03 01 03 01 03 01 03 01 03 01 02 01 02 01  ................
00000d33: 03 01 02 01 02 01 02 01 02 01 02 01 02 01 02 01  ................
00000d43: 02 01 02 01 02 01 02 01 02 01 02 01 02 01 02 01  ................
00000d53: 02 01 02 01 02 01 02 01 02 01 02 01 05 07 01 02  ................
00000d63: 01 02 01 02 01 02 01 02 01 02 01 02 01 02 01 02  ................
00000d73: 06 07 06 07 06 07 06 07 06 07 06 07 06 07 06 07  ................
00000d83: 06 07 06 07 06 07 06 07 06 07 06 07 06 07 06 07  ................
00000d93: 06 07 06 07 06 07 06 07 06 07 06 07 06 07 06 07  ................
00000da3: 06 07 06 07 06 07 06 07 06 07 06 07 06 07 06 07  ................
00000db3: 06 07 06 07 06 07 06 07 06 07 06 07 06 07 06 07  ................
00000dc3: 06 07 06 07 06 07 06 07 06 07 06 07 06 07 06 07  ................
00000dd3: 06 07 06 07 06 07 06 07 06 07 06 07 06 07 06 07  ................
00000de3: 06 07                                            ..
  $ xxd -s 0xde5 -l 0x30 -g6 -c12 /usr/share/zoneinfo/Europe/London
00000de5: ffffffb50000 00000e100104  ............
00000df1: 000000000008 00001c20010c  ......... ..
00000dfd: 000000000008 00000e100004  ............
00000e09: 00000e100104 000000000008  ............
$ xxd -s 0xe15 -l 0x11 -g1 /usr/share/zoneinfo/Europe/London
00000e15: 4c 4d 54 00 42 53 54 00 47 4d 54 00 42 44 53 54  LMT.BST.GMT.BDST
00000e25: 00                                               .
$ xxd -s 0xe26 -l 0x10 -g1 /usr/share/zoneinfo/Europe/London
00000e26: 00 01 01 01 00 00 01 01 00 00 00 00 00 00 01 01  ................
$ xxd -s 0xe36 -l 0x1a -g1 /usr/share/zoneinfo/Europe/London
00000e36: 0a 47 4d 54 30 42 53 54 2c 4d 33 2e 35 2e 30 2f  .GMT0BST,M3.5.0/
00000e46: 31 2c 4d 31 30 2e 35 2e 30 0a                    1,M10.5.0.

-- 
Take care. Thanks, Brian Inglis              Calgary, Alberta, Canada

La perfection est atteinte                   Perfection is achieved
non pas lorsqu'il n'y a plus rien à ajouter  not when there is no more to add
mais lorsqu'il n'y a plus rien à retirer     but when there is no more to cut
                                 -- Antoine de Saint-Exupéry


      reply	other threads:[~2024-04-18  5:30 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <36001589.119195.1713339202522.ref@mail.yahoo.com>
2024-04-17  7:33 ` alf salte
2024-04-18  5:30   ` Brian Inglis [this message]

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