Patching Files
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For updating files WoW uses bsdiff. Have a look at "http://www.daemonology.net/bsdiff/" or "http://www.pokorra.de/coding/bsdiff.html"
I had try bsdiff, but it doesn't work.
1. extract achievement.dbc from enUS\DBFilesClient in Patches\WoW-3.1.3-to-3.2.0-enUS-Win-patch\wow-partial-1.MPQ 2. rename it to achievement.dbc.patch (45K) 3. extract achievement.dbc from DBFilesClient in Data\enUS\patch-enUS-2.MPQ 4. rename it to achievement.dbc.old 5. bsdiff usage: bspatch.exe oldfile newfile patchfile 6. bsdiff chievement.dbc.old achievement.dbc achievement.dbc.patch Corrupt patch 7. extract achievement.dbc from DBFilesClient in PTR:Data\enUS\patch-enUS-2.MPQ 8. rename it to achievement.dbc.ptr 9. bsdiff achievement.dbc.old achievement.dbc.ptr achievement.dbc.patch-ptr (20K)
althought it shows "BSDIFF40" in it's header, but it is not a bsdiff?
-- chuanhsing
I got some information about files in pre-download mpq. All files inside it are "patch" files.
Followings are for new file patch header:
0x0000 2 bytes: Size of the patch header (I've only seen 0x18)
0x0002 2 bytes: Flags
* 0x0004 seems always set
* 0x0100 unknown, set when new file patch
* 0x0400 means BSDIFF40 patch
0x0004 4 bytes: Looks like CRC
0x0008 4 bytes: unknown
0x000C 4 bytes: file size (only if Flags = 0x0100)
0x0010 8 bytes: timestamp as FILETIME
---- body ----
0x0018 n bytes: the real thing
Followings are for BSDIFF40 patch header:
0x0000 2 bytes: Size of the patch header (I've only seen 0x18)
0x0002 2 bytes: Flags
* 0x0004 seems always set
* 0x0100 unknown
* 0x0400 means BSDIFF40 patch
0x0004 4 bytes: Looks like CRC
0x0008 4 bytes: unknown
0x000C 4 bytes:
0x0010 8 bytes: timestamp
---- body ----
0x0018 4 bytes: file size
0x001C 1 byte: unknown
0x001D 8 bytes: signature, "BSDIFF40"
0x0025 n bytes: unknown
For the new files, I can skip heading 24 bytes and get the real thing! But I still can't understand the things after BSDIFF40.
-- chuanhsing