Extension:File_File_SPFF

Extension File_File_SPFF

SPFF(SFENCE Part File Format) is a method for quick work with files with special uses. It is possible to do quick cut or paste data to SPFF file. But common reading and writing can be slower.

The first byte of SPFF file is version. Now is supported version 4 and 8 (32bit and 64bit).
The header is following.

Header parts:

• size (32bit or 64bit)
• first file data block offset (32bit or 64bit)
• last file data block offset (32bit or 64bit)
• number of help blocks (32bit or 64bit)

Help blocks is following behind the header.
Help block parts:

• data offset (32bit or 64bit)
• file data block offset (32bit or 64bit)

Data blocks is following behind help blocks.
Data block header parts:

• next data block offset (32bit or 64bit)
• data block size (32bit or 64bit)

You can see, that SPFF extension must hold correct main SPFF header, help blocks and data block headers. Unused help blocks have data offset set to zero value. Help blocks aren't necessary for work with SPFF file. But they make quicker use of Set_Position function. It can be very useful.