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EgoEngineModding / ego.nefsedit

NeFS archive editor for Ego Engine
MIT License
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Support for NeFS version 0x10600 (DiRT Rally 1, F1, etc) #13

Closed opcod3 closed 4 years ago

opcod3 commented 4 years ago

Dirt Rally uses a different NeFS format compared to Dirt Rally 2.0 and Dirt 4. After updating the header to the new format reading the archive still fails.

Apparently NeFS should support duplicate entries, this is also supported by the existence of the following function in F1 2018: neon::NeFileSystem::getFirstDuplicateEntry. Which uses the same NeFS format. So we should somehow figure out how that works.

victorbush commented 4 years ago

List of NeFS versions used by different games. Posting this here for reference: Dirt 3: 0x10501 (according to the miek/dirt3-modding github, although at a different offset) Grid 2: 0x10600 DR1: 0x10600 F12017/2018: 0x10600 Grid 2019: 0x10600 D4: 0x20000 DR2: 0x20000

victorbush commented 4 years ago

I played with it a little last week, it looked like there was 4 bytes difference in the header table of contents before the part offsets. Part 4 entries look different as well, I haven't been able to figure them out yet.

Appears to have references extracted offsets in 0x20000 increments (the last value is the extracted size).

Example part 4 excerpt:
00 00 02 00 04 00 B9 9F
00 00 04 00 04 00 B0 85
00 00 06 00 04 00 6B ED
00 00 08 00 04 00 D4 56
00 00 0A 00 04 00 F7 B0
00 00 0C 00 04 00 D3 25
00 00 0E 00 04 00 75 C1
00 00 10 00 04 00 95 AB
00 00 12 00 04 00 CD 8C
00 00 14 00 04 00 6B 2E
00 00 16 00 04 00 86 ED
00 00 18 00 04 00 AA 35
00 00 1A 00 04 00 98 E6
00 00 1C 00 04 00 DC 44
00 00 1E 00 04 00 6B 44
00 00 20 00 04 00 84 85
00 00 22 00 04 00 E9 32
00 00 24 00 04 00 86 23
00 00 26 00 04 00 3C A2
00 00 28 00 04 00 63 63
00 00 2A 00 04 00 38 FA
00 00 2C 00 04 00 61 A7
00 00 2E 00 04 00 AB E0
00 00 30 00 04 00 A5 DA
00 00 32 00 04 00 BE 55
00 00 34 00 04 00 59 6E
00 00 36 00 04 00 2C CB
00 00 38 00 04 00 E1 30
00 00 3A 00 04 00 A6 0E
00 00 3C 00 04 00 15 25
00 00 3E 00 04 00 64 F7
00 00 40 00 04 00 0A 2D
00 00 42 00 04 00 E8 60
00 00 44 00 04 00 69 E6
00 00 46 00 04 00 23 55
00 00 48 00 04 00 B2 DD
00 00 4A 00 04 00 FE 9E
00 00 4C 00 04 00 A1 F2
00 00 4E 00 04 00 F1 2C
00 00 50 00 04 00 C8 4D
00 00 52 00 04 00 E5 37
00 00 54 00 04 00 94 7B
00 00 56 00 04 00 06 2F
00 00 58 00 04 00 D4 AC
00 00 5A 00 04 00 5B 7D
00 00 5C 00 04 00 42 C6
00 00 5E 00 04 00 86 BA
00 00 60 00 04 00 95 E0
00 00 62 00 04 00 5B A0
00 00 64 00 04 00 A1 57
00 00 66 00 04 00 49 36
00 00 68 00 04 00 2A 54
00 00 6A 00 04 00 E2 FD
00 00 6C 00 04 00 E4 86
00 00 6E 00 04 00 5D 2D
00 00 70 00 04 00 2D 83
00 00 72 00 04 00 68 89
00 00 74 00 04 00 2E 64
00 00 76 00 04 00 AA AB
00 00 78 00 04 00 39 D4
00 00 7A 00 04 00 FB B3
00 00 7C 00 04 00 18 DB
00 00 7E 00 04 00 68 47
00 00 80 00 04 00 99 32
80 00 80 00 04 00 5C 8B
opcod3 commented 4 years ago

I have finished reversing the part 4 headers for version 0x10600, this is it.

Start Size Description
0x00 0x04 Cumulative block size
0x04 0x02 Transformation type
0x06 0x02 Checksum (crc16 maybe) or simple checksum

Edit: Figured out transformation type:

Type Transformation
0x0 No transformation
0x4 AES Decrypt
0x7 Zlib Decompress
victorbush commented 4 years ago

Support for 1.6 headers added in version 0.6.0. Also updated to handle duplicate items.