Darksecond · May 23, 2017 08:00 · May 23, 2017 · Apr 7, 2017 · Apr 7, 2017 · Apr 7, 2017
diff --git a/patch_v3.ksy b/patch_v3.ksy
@@ -0,0 +1,169 @@
+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.
diff --git a/README.md b/README.md
@@ -1,7 +1,6 @@
 # Halo 2 patch_v3.lvl signer/checker.
 
-The chunk checksum is just a CRC32. It seems to be a slighty weird one in that there seems to be signed/unsigned difficulties.
-This is fixed in the javascript for all my test cases.
+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.
diff --git a/patch.js b/patch.js
@@ -14,7 +14,8 @@ for(let index = 0; index < maps; index++) {
   chunk[6] = 0;
   chunk[7] = 0;
 
-  // Weirdities to make CRC32 behave. It matches all my test cases.
-  let crc = (CRC32.buf(chunk)*-1 >>> 0) - 1;
+  // checksum seems to be inverted.
+  // So invert & treat as unsigned.
+  let crc = ~CRC32.buf(chunk) >>> 0;
   console.log(checksum.toString(16), crc.toString(16));
 }
diff --git a/package.json b/package.json
@@ -4,14 +4,12 @@
   "description": "",
   "main": "patch.js",
   "dependencies": {
-    "crc": "^3.4.4",
-    "crc-32": "^1.0.1",
-    "crc32": "^0.2.2"
+    "crc-32": "^1.0.1"
   },
   "devDependencies": {},
   "scripts": {
     "test": "echo \"Error: no test specified\" && exit 1"
   },
-  "author": "",
+  "author": "Tim Peters",
   "license": "ISC"
 }
diff --git a/README.md b/README.md
@@ -0,0 +1,7 @@
+# Halo 2 patch_v3.lvl signer/checker.
+
+The chunk checksum is just a CRC32. It seems to be a slighty weird one in that there seems to be signed/unsigned difficulties.
+This is fixed in the javascript for all my test cases.
+Right now it does nothing except check the signatures of each chunk.
+
+It is easy to add json serialization/unserialization later.
diff --git a/package.json b/package.json
@@ -0,0 +1,17 @@
+{
+  "name": "patchnode-19232",
+  "version": "1.0.0",
+  "description": "",
+  "main": "patch.js",
+  "dependencies": {
+    "crc": "^3.4.4",
+    "crc-32": "^1.0.1",
+    "crc32": "^0.2.2"
+  },
+  "devDependencies": {},
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1"
+  },
+  "author": "",
+  "license": "ISC"
+}
diff --git a/patch.js b/patch.js
@@ -0,0 +1,20 @@
+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;
+
+  // Weirdities to make CRC32 behave. It matches all my test cases.
+  let crc = (CRC32.buf(chunk)*-1 >>> 0) - 1;
+  console.log(checksum.toString(16), crc.toString(16));
+}