FastFiles and Zone files (AW)

FastFile Structure

enum DB_CompressorType
{
  DB_COMPRESSOR_INVALID = 0xFFFFFFFF,
  DB_COMPRESSOR_ZLIB = 0x1,
  DB_COMPRESSOR_LZX = 0x2,
  DB_COMPRESSOR_PASSTHROUGH = 0x3,
};
 
struct GfxImageStreamData
{
  int unknown[3];
};

struct FF_Header
{
  char magic[8]; // S1ff0100
  int version;
  bool compress;
  DB_CompressorType compressType;
  char sizeOfPointer;
  char sizeOfLong;
  int fileTimeHigh;
  int fileTimeLow;
  int imageCount;
  GfxImageStreamData imageData[imageCount];
  int baseFileLen;
  int totalFileLen;
};

Magic

The magic is a string that is 8 characters long. It is either "S1ff0100" or "S1ffu100". It indicates what is read after maxFileSize. If it is "S1ff0100" then this fastfile is signed. If it is "S1ffu100", then this fastfile is unsigned.

Version

Helps to dictate the version of the fastfile, so Ghosts fastfiles cannot be loaded on Advanced Warfare. The Advanced Warfare version is 0x72E for the Playstation 3 and Xbox 360 consoles, and the same for PC.

 if (version > 0x72E)
  Com_Error(ERR_DROP, "Fastfile for zone '%s' is newer than client executable (version %d, expecting %d)", filename, version, 0x72E);
 else if (version < 0x72E)
  Com_Error(ERR_DROP, "Fastfile for zone '%s' is out of date (version %d, expecting %d)", filename, version, 0x72E);

Compress

Whether or not the zone is compressed inside the fastfile.

Image Data

These are still not entirely understood.

File Sizes

The baseFileLen is the size of the fastfile, everything included. The totalFileLen is the highest number that baseFileLen can be, and in most fastfiles they are equal.

Sub Header

The rest of the fastfile is read depending on what the main fastfile magic was. If the magic was "S1ff0100" then the fastfile is signed. If it was "S1ffu100", the fastfile is unsigned.

Unsigned Files

The only data remaining is compressed data, depending on the enum in the header of the fastfile. Decompressing the data yields the zone file.

Signed Files

 struct DB_AuthHash
 {
   char bytes[32];
 };
 
 struct DB_AuthSignature
 {
   char bytes[256];
 };
 
 struct DB_AuthHeader
 {
   char magic[8]; // S1ffS100
   int reserved;
   DB_AuthHash subheaderHash;
   DB_AuthSignature signedSubheaderHash;
   struct 
   { 
     char fastfileName[32];
     int reserved;
     DB_AuthHash masterBlockHashes[244];
   } subheader;
   char signatureBlock[0x1E030];
 };

The signatures on the XBlocks are checked as the fastfile loads. Then the sub-header master block hashes are checked, followed by the signedSubheaderHash, and lastly the subheaderHash. If any fail, then the loading of the FF is aborted. Only Activision and the game developers can generate the RSA signatures.

Magic

The subheader magic is always "S1ffS100".

PS3

After the zone file is created, it is split into blocks each 0x10000 bytes. Each block is compressed using default zlib compression. The size of the compressed block is stored as an unsigned 16 bit integer over the zlib header (0x78DA). Compressed blocks are concatenated and appended to the fastfile.

Zone File

The zone file is the decompressed data from an FF.

Header

#define XFILE_BLOCK_TEMP 0x0
#define XFILE_BLOCK_PHYSICAL 0x1
#define XFILE_BLOCK_RUNTIME 0x2
#define XFILE_BLOCK_VIRTUAL 0x3
#define XFILE_BLOCK_LARGE 0x4
#define XFILE_BLOCK_CALLBACK 0x5
#define XFILE_BLOCK_SCRIPT 0x6
#define MAX_XFILE_COUNT 0x7
#ifdef PS3
  #define MAX_XFILE_COUNT 0x8
#endif


struct XFile
{
  unsigned int size;
  unsigned int externalSize;
  unsigned int blockSize[MAX_XFILE_COUNT];
};

Asset List

struct XAsset
{
  XAssetType type;
  XAssetHeader header;
};

struct ScriptStringList
{
  int count;
  const char **strings;
};

struct XAssetList
{
  ScriptStringList stringList;
  int assetCount;
  XAsset *assets;
  XGlobals *globals;
};