FastFiles are the CoD engine's way of storing Zone files. FastFiles (FFs) almost always have some sort of RSA2048 signature, a zlib compression along the way, and then on later CoDs some encryption. The Zones are a library of assets. Every FF in every CoD game starts the same way...
|Magic||0x0||char||"IWffu100" for unsigned fastfiles, "IWff0100" for signed fastfiles, "TAff0100" for treyarch's Black Ops 2 fastfile, "S1ff0100" for Sledgehammer Advanced Warfare fastfiles, and finally TAff0000 for Black Ops III fastfile.|
So by reading the version of the input FF, you can tell what system and game the FF is from.
|XFILE_VERSION||007:QoS||CoD4||WaW||MW2||BO1||MW3||BO2||Ghosts||CoD: Online||Advanced Warfare||BO3 Beta||BO3|
Pointers in Zone Files
Infinity Ward implemented their own way of loading data that can already be found earlier in the zone file. What should be an address in memory is instead stored either as -1, -2, or as an offset. If the pointer is -1 or -2, than the data follows the header, typically in order. If the pointer is not -1 or -2, the first 4 bits are extracted and used as an index for the g_streamBlocks array. The other bits are the offset and is added to the data pointer in g_streamBlocks. The offset is only correct after the zone file has been loaded in memory. This is because some data is relocated which changes the size of the zone. Some differences:
- strings are aligned by 4 bytes
- asset headers are stored in pools
- sound, image, and shader programs are stored in pools
- zone header is removed