XDBF (Xbox Data Base File) files are used by the Xbox 360 as a generic database. It is used as the format for GPD (Gamer Profile Data) and SPA (Statistics, Presence and Achievements) files. SPA files are linked into an Xbox 360 executable during compilation and are used by the dashboard to generate the GPD, Save Game (STFS) Meta-Data and Images. In the XAM the DataFile class handles all of the operations associated with these files.
Total length: 24 bytes (0x18)
Byte ordering: Dependant on magic. If the magic is little endian then the whole file is and is a GFWL, if it's big endian then it's an Xbox file.
|0x0||0x4||ascii string||Magic (0x58444246)|
|0x4||0x4||unsigned int||Version (0x10000)|
|0x8||0x4||unsigned int||Entry Table Length (in number of entries)|
|0xC||0x4||unsigned int||Entry Count|
|0x10||0x4||unsigned int||Free Space Table Length (in number of entries)|
|0x14||0x4||unsigned int||Free Space Table Entry Count|
Entry Table Length and Free Space Table Length will be a multiple of 512, this is just Xbox's preferred values, but it will read the file if you decrease them to make the size of the file smaller, alot smaller.
The Entry Table is made up of entries, each one under a different namespace and ID. The table length will be Entry Table Length * 18, but only the first Entry Count are used.
Total length: 18 bytes (0x12)
|0x0||0x2||unsigned short||Namespace (see [[GPD|
Free Space Table
The Free Space Table is used to map out the unused space within the file. It is updated whenever n entry changes size. Each entry within the Free Space Table is composed of the OffsetSpecifier and how much space is unused their (Length). The final entry in the Free Space Table isn't actually free space, but rather is information about the length of data after the tables. The OffsetSpecifier would be the length (file length - header and tables) and the Length would be -1 -OffsetSpecifier.
Free Space Entry Structure
Total length: 8 bytes
Entry Data Offset
To work out the real entry data offset, times the Entry Table Length by 0x12, then times the Free Space Table Length by 0x8 and add the result together, and add 0x18 (file header). This is where the beginning of the entry data begins, then add the OffsetSpecifier by the entry to get the real offset.
(((Entry Table Length * 18) + (Free Space Table Length * 8)) + 24) + OffsetSpecifier
Just to explain a bit more,
Entry Table Length * 18, 18 being the length of each entry, this will workout the actual length of the entry table.
Free Space Table Length * 8, 8 being the length of each free space entry, workout the actual length of the free space table.
+ 24, 24 is the length of the header.