Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

add Youtube video for static type encoding in LSP2 Standard page #583

Merged
merged 2 commits into from
Jul 12, 2023
Merged

add Youtube video for static type encoding in LSP2 Standard page #583

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
f5689ba
add Youtube video for static type encoding in LSP2
CJ42 Jul 12, 2023
41bac13
Merge branch 'main' into lsp2-encoding
Hugoo Jul 12, 2023
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
37 changes: 37 additions & 0 deletions docs/standards/generic-standards/lsp2-json-schema.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -234,3 +234,40 @@ bytes32 dataKey = bytes32(
```

</details>

## `valueType` encoding

:::success Recommendation

Watch our following video for an overview of how static types (`uintM`, `bytesN`, `bool`), `bytes` and `string` are encoded in the [ERC725Y](../lsp-background/erc725.md#erc725y-data-representation) storage of a smart contract using the LSP2 standard.

:::

<div class="video-container">
<iframe src="https://www.youtube.com/embed/6uj8Lbodf5A" title="LSP2 Encoding - static types" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
</div>

LSP2 differs in terms of how data is encoded depending on its type. As a basic summary, LSP2 and the [ABI](https://docs.soliditylang.org/en/latest/abi-spec.html) encoding specification can be compared as follow:

**Differences:**

- static types (types that have a fixed size like `uintM`, `bytesN` and `bool`) are encoded as they are without any padding to make a 32 bytes long word.
- `bytes` and `string` are also encoded as they are as arbitrary bytes, without any 32 bytes words for the offset or the data length.

**Similarities**

- any array types (_e.g: `uintM[]`, `bytesN[]`, `bool`, etc..._) in LSP2 are ABI encoded the same way as the ABI specification.

Below is a table that describe the LSP2 encoding format for `valueTypes`.

| `valueType` | Encoding | Example |
| -------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------- |
| `bool` | `0x01` (for `true`) or `0x00` (for `false`) | |
| `string` | as utf8 hex bytes <br/> **without padding ❌** | `"Hello"` --> `0x48656c6c6f` |
| `address` | as a 20 bytes long address | `0x388C818CA8B9251b393131C08a736A67ccB19297` |
| `uin256` | as a hex value 32 bytes long <br/> **left padded** with zeros to fill 32 bytes | number `5` --> `0x0000000000000000000000000000000000000000000000000000000000000005` |
| `uintM` <br/> (where ` N` is a multiple of **8 bits** in the range`8 > N > 256`) | as a hex value **`M` bits long** <br/> **left padded** with zeros to fill `M` bytes | number `5` as `uint32` --> `0x00000005` |
| `bytes32` | as a hex value 32 bytes long <br/> **right padded** to fill 32 bytes | `0xca5ebeeff00dca11ab1efe6701df563bc1add009076ded6bcf4c6f771f2e3436` |
| `bytes4` | as a hex value 4 bytes long <br/> **right padded** to fill 4 bytes | `0xcafecafe` |
| `bytesN` (from 1 to 32) | as a hex value **`N` bytes long** <br/> **right padded** to fill `N` bytes | |
| `bytes` | as hex bytes of any length <br/> **without padding** ❌ | `0xcafecafecafecafecafecafecafecafe...` |