Write binary format spec about hive

[simc]

I haven't started to document the binary format.

It looks like this:

Each key-value combination is called frame. Each frames has four components:

1. Frame header:

uint32 frame lenght

uint8 key type

2. key

string key:

unit8 key lenght

uint8 keyChar1

...

uint8 keyCharN

int key:

uint32 key

 

3. value

Ints and doubles are always stored as 8-byte double

Lists, Maps and Strings have an uint32 which contains the length.

uint32 listLength

float64 value1

...

float64 valueN

uint32 stringLength (in bytes)

uint8 codeUnit1

...

uint8 codeUnitN

Non primitive lists and primitive lists which contain at least one null value store the type of each element:

uint32 listLength

uint8 type1

any value1

...

uint8 typeN

any valueN

4. Checksum

Each frame ends with a 4-byte checksum (CRC32) of all other bytes (including the 4 length bytes)

Sorry, I know this is not much information but it's all I got atm.

You can find most of the implementation in the Frame class, the BinaryReaderImpl and the BinaryWriterImpl.

Don't hesitate to ask if you have problems.