All binary file format in MapDB start with 32byte header. That identifies type of file, its format version and features used in
- 2 bytes - format ID, (
- 2 bytes - format version,
- number increases with backward incompatible changes (new features)
- MapDB will refuse to open newer formats to prevent data corruption
- 4 bytes - Wide Flags; features supported by most formats
- file wide checksum ?, type of checksum used… (CRC32,)
- file size supported?
- pointer checksums?
- type of compression?
- some basic serialization info?
- is the space zeroed out?
- 8 bytes - file size, if set in wide feature flag
- 8 bytes - 64 bit or 32bit checksum (both will use 8 bytes)
- 8 bytes - Format Flags - features only supported by single format
- type of pointer checksums
- how zero space