patch_v3.lvl

README.md

Halo 2 patch_v3.lvl signer/checker.

The chunk checksum is just a CRC32. It seems to be inverted though. Right now it does nothing except check the signatures of each chunk.

It is easy to add json serialization/unserialization later.

package.json

{
  "name": "patchnode-19232",
  "version": "1.0.0",
  "description": "",
  "main": "patch.js",
  "dependencies": {
    "crc-32": "^1.0.1"
  },
  "devDependencies": {},
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "Tim Peters",
  "license": "ISC"
}

patch.js

const CRC32 = require('crc-32');

const fs = require('fs');

const buffer = fs.readFileSync('./patch_v3.lvl.3');
const header = buffer.slice(0,8);
const maps = buffer.readUInt32LE(4);
console.log(maps);
for(let index = 0; index < maps; index++) {
  let chunk = buffer.slice(8+185344*index,8+185344*(index+1));
  let checksum = chunk.readUInt32LE(4);
  chunk[4] = 0;
  chunk[5] = 0;
  chunk[6] = 0;
  chunk[7] = 0;

  // checksum seems to be inverted.
  // So invert & treat as unsigned.
  let crc = ~CRC32.buf(chunk) >>> 0;
  console.log(checksum.toString(16), crc.toString(16));
}

patch_v3.ksy

meta:
  id: patch_v3
  file-extension: lvl
  endian: le
instances:
  header:
    type: header
    pos: 0
  maps:
    type: map
    pos: 8
    repeat: expr
    repeat-expr: header.map_count
    size: 185344
types:
  max_teams:
    seq:
      - id: none
        type: u1
      - id: ctf
        type: u1
      - id: slayer
        type: u1
      - id: oddball
        type: u1
      - id: koth
        type: u1
      - id: race
        type: u1
      - id: headhunter
        type: u1
      - id: juggernaught
        type: u1
      - id: territories
        type: u1
      - id: assault
        type: u1
      - id: stub_10
        type: u1
      - id: stub_11
        type: u1
      - id: stub_12
        type: u1
      - id: stub_13
        type: u1
      - id: stub_14
        type: u1
      - id: stub_15
        type: u1
  header:
    seq:
      - id: version
        type: u4
      - id: map_count
        type: u4
  map:
    seq:
      - id: version
        type: u4
      - id: patch_checksum
        type: u4
        doc: >
          Inverted CRC32 of the chunk, patch_checksum field should be zero.
          A chunk is 185344 bytes long.
          It does not include the 8 byte file header.
      - id: unknown2
        type: u4
        doc: always seems to be '1'
      - id: scenario
        type: str
        encoding: UTF-8
        size: 256
      - id: map_checksum
        type: u4
      - id: map_end
        type: u4
        doc: offering_id?
      - id: unknown5
        type: u4
        doc: always seems to be '0xFFFFFFFF'
      - id: name_en
        type: str
        encoding: UTF-16
        size: 64
      - id: name2
        type: str
        encoding: UTF-16
        size: 64
      - id: name_de
        type: str
        encoding: UTF-16
        size: 64
      - id: name_fr
        type: str
        encoding: UTF-16
        size: 64
      - id: name5
        type: str
        encoding: UTF-16
        size: 64
      - id: name6
        type: str
        encoding: UTF-16
        size: 64
      - id: name_ch
        type: str
        encoding: UTF-16
        size: 64
      - id: name8
        type: str
        encoding: UTF-16
        size: 64
      - id: name9
        type: str
        encoding: UTF-16
        size: 64
      - id: description_en
        type: str
        encoding: UTF-16
        size: 256
      - id: description2
        type: str
        encoding: UTF-16
        size: 256
      - id: description_de
        type: str
        encoding: UTF-16
        size: 256
      - id: description_fr
        type: str
        encoding: UTF-16
        size: 256
      - id: description5
        type: str
        encoding: UTF-16
        size: 256
      - id: description6
        type: str
        encoding: UTF-16
        size: 256
      - id: description_ch
        type: str
        encoding: UTF-16
        size: 256
      - id: description8
        type: str
        encoding: UTF-16
        size: 256
      - id: description9
        type: str
        encoding: UTF-16
        size: 256
      - id: map_start
        type: u4
      - id: unknown6
        type: u4
        doc: >
          always seems be '0'.
          Possibly flags or sort order?
      - id: max_teams
        type: max_teams
      - id: raw_dxt1
        size: 0x2C790
        doc: >
          This is DDS file with DXT1.
          Width is 220.
          Height is 207.
          Size is 0x2C790.
          This is the raw dxt1 bitmap, it just needs a header.