.rou files

Author: Trolldemorted

src/SUMMARY.md

@@ -74,6 +74,7 @@
     - [Town Hall Details](./patches/town-hall-details.md)
 - [File Formats](./file-formats.md)
     - [CPR](./file-formats/cpr.md)
+    - [Trade Routes (.rou)](./file-formats/rou.md)
     - [Navigation Matrix](./file-formats/navigation-matrix.md)
     - [Navigation Vector](./file-formats/navigation-vector.md)
     - [Navpoint Matrix](./file-formats/navpoint-matrix.md)

src/file-formats/rou.md

@@ -0,0 +1,34 @@
+# Trade Routes (.rou)
+The saved trade routes are stored in `./Save/AutoRoute`.
+An uncomporessed trade route is an array of route stops, 220 bytes each.
+The rou file format is defined as:
+```
+          | 00  01   02  03   04  05   06  07 |
+00000000  | Output Length   | Data            |
+```
+
+If the output length is bigger than `0` the file is compressed.
+Otherwise the absolute value of the negative output length denotes the length.
+
+## Compression
+The compression algorithm has not been identified, but the decompression was [reproduced](https://github.com/P3Modding/p3-lib/tree/master/p3-rou).
+
+## Trade Route Stops
+A trade route stop is defined as:
+```
+          |           00           01           02           03           |
+00000000  | Unused                        | Town Index | Action           |
+00000004  | Ware Order Array                                              |
+...
+0000001c  | Ware Price Array                                              |
+...
+0000007c  | Ware Amount Array                                             |
+```
+The "direction" of a transaction is encoded in the price and amount:
+
+|Price|Amount|Direction|
+||||
+|0|Negative|Ship -> Office|
+|0|Positive|Office -> Ship|
+|Positive|Positive|Ship -> Town|
+|Negative|Any|Town -> Ship|