status-im
/
nimbus-eth2
mirror of https://github.com/status-im/nimbus-eth2.git
2
0
Fork 0
Code Issues Projects Releases Wiki Activity

Use SSZ object to define header

This commit is contained in:
Jacek Sieka 2022-10-25 11:13:33 +02:00
parent f9830836a9
commit d00a3f1dae
No known key found for this signature in database
GPG Key ID: A1B09461ABB656B8
1 changed files with 6 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
docs/e2store.md
View File

@ -12,14 +12,14 @@ The `e2store` (extension: `.e2s`) is a simple linear [Type-Length-Value](https:/
The type and length are encoded in an 8-byte header which is directly followed by data.
```
record = header | data
header = type | length
type = Vector[byte, 2]
length = Vector[byte, 6]
The header corresponds to an SSZ object defined as such:
```python
class Header(Container):
type: Vector[byte, 2]
length: uint48
```
The `length` is the first 6 bytes of a little-endian encoded `uint64`, not including the header itself. For example, the entry with header type `[0x22, 0x32]`, the length `4` and the bytes `[0x01, 0x02, 0x03, 0x04]` will be stored as the byte sequence `[0x22, 0x32, 0x04, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x02, 0x03, 0x04]`.
The `length` is the length of the data that follows the header, not including the length of the header itself. For example, the entry with header type `[0x22, 0x32]`, the length `4` and the bytes `[0x01, 0x02, 0x03, 0x04]` will be stored as the byte sequence `[0x22, 0x32, 0x04, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x02, 0x03, 0x04]`.
`.e2s` files may freely be concatenated, and may contain out-of-order records.