fixed-kv

fixed-kv is a in memory disk persisted key value storage engine of fixed size (4KB), with a dead simple binary format.

A new fixedkv instance will use in memory btree for Get and Set operations. Closing the fixedkv will write to disk where.

Data can be read using the fixedkv.Open(). This will load the database in read only mode, to allow reading of keys and values again.

To edit a database, create a new database using fixedkv.New() and manually insert from disked backed copy.

Format

First 96 bytes of the file is used for storing the header.

<----------Header---------->
| version | #keys | unused |   offsets    | key-values |
| 4B      | 2B    | 90B    |   #keys * 2B | ...        |

• File format version
• Number of keys
• Unused bytes for future use
• Offset pointing to key/value pairs in the file
• The stored key/value pairs of variable length key and values

Key Value format

| key len | value len | key | val |
|   2B    |    2B     | ... | ... |

TODO

• bounds checking for insert operations to keep within 4KB size
• ability to edit persisted database file