File Name Directory Entry

Offset Size Description Comments
0 (0x00) 1 EntryType 0xC1
1 (0x01) 1 GeneralSecondaryFlags*
2 (0x02) 30 FileName

* GeneralSecondaryFlags

Bits Size Attribute Comments
0 1 AllocationPossible Must be 0
1 1 NoFatChain Must be 0
2 14 CustomDefined

File Name directory entries must immediately follow the Steam Extension directory entry in the number of NameLength/15 rounded up.

The maximum number of File Name entries is 17, each can hold up to 15 Unicode characters and the maximum file name length is 255. Unused portion of FileName field must be set to 0x0000.

Invalid File Name Characters

Character Code Character Description
0x0000 - 0x001F Control codes
0x0022 " Quotation mark
0x002A * Asterisk
0x002F / Forward slash
0x003A : Colon
0x003C < Less than
0x003E > Greater than
0x003F ? Question mark
0x005C \ Back slash
0x007C | Vertical bar