JBMetadataResolver

Library to parse and create metadata to store {id: data} entries.

*Metadata are built as:

32B of reserved space for the protocol
a lookup table Id: offset, defining the offset of the data for a given 4 bytes id. The offset fits 1 bytes, the ID 4 bytes. This table is padded to 32B.
the data for each id, padded to 32B each +-----------------------+ offset: 0 | 32B reserved | +-----------------------+ offset: 1 = end of first 32B | (ID1,offset1) | | (ID2,offset2) | | 0's padding | +-----------------------+ offset: offset1 = 1 + number of words taken by the padded table | id1 data1 | | 0's padding | +-----------------------+ offset: offset2 = offset1 + number of words taken by the data1 | id2 data2 | | 0's padding | +-----------------------+*

State Variables

ID_SIZE

uint256 constant ID_SIZE = 4;

ID_OFFSET_SIZE

uint256 constant ID_OFFSET_SIZE = 1;

WORD_SIZE

uint256 constant WORD_SIZE = 32;

TOTAL_ID_SIZE

uint256 constant TOTAL_ID_SIZE = 5;

NEXT_ID_OFFSET

uint256 constant NEXT_ID_OFFSET = 9;

RESERVED_SIZE

uint256 constant RESERVED_SIZE = 32;

MIN_METADATA_LENGTH

uint256 constant MIN_METADATA_LENGTH = 37;

Functions

addToMetadata

Add an {id: data} entry to an existing metadata. This is an append-only mechanism.

function addToMetadata(
    bytes memory originalMetadata,
    bytes4 idToAdd,
    bytes memory dataToAdd
)
    internal
    pure
    returns (bytes memory newMetadata);

Parameters

Name	Type	Description
`originalMetadata`	`bytes`	The original metadata
`idToAdd`	`bytes4`	The id to add
`dataToAdd`	`bytes`	The data to add

Returns

Name	Type	Description
`newMetadata`	`bytes`	The new metadata with the entry added

createMetadata

Create the metadata for a list of {id:data}

Intended for offchain use (gas heavy)

function createMetadata(bytes4[] memory ids, bytes[] memory datas) internal pure returns (bytes memory metadata);

Parameters

Name	Type	Description
`ids`	`bytes4[]`	The list of ids
`datas`	`bytes[]`	The list of corresponding datas

Returns

Name	Type	Description
`metadata`	`bytes`	The resulting metadata

getDataFor

Parse the metadata to find the data for a specific ID

Returns false and an empty bytes if no data is found

function getDataFor(bytes4 id, bytes memory metadata) internal pure returns (bool found, bytes memory targetData);

Parameters

Name	Type	Description
`id`	`bytes4`	The ID to find.
`metadata`	`bytes`	The metadata to parse.

Returns

Name	Type	Description
`found`	`bool`	Whether the `{id:data}` was found
`targetData`	`bytes`	The data for the ID (can be empty)

getId

Returns an unique id following a suggested format (xor(address(this), purpose name) where purpose name is a string giving context to the id (Permit2, quoteForSwap, etc)

function getId(string memory purpose) internal view returns (bytes4);

Parameters

Name	Type	Description
`purpose`	`string`	A string describing the purpose associated with the id

Returns

Name	Type	Description
`<none>`	`bytes4`	id The resulting ID.

getId

Returns an unique id following a suggested format (xor(address(this), purpose name) where purpose name is a string giving context to the id (Permit2, quoteForSwap, etc)

function getId(string memory purpose, address target) internal pure returns (bytes4);

Parameters

Name	Type	Description
`purpose`	`string`	A string describing the purpose associated with the id
`target`	`address`	The target which will use the metadata

Returns

Name	Type	Description
`<none>`	`bytes4`	id The resulting ID.

_sliceBytes

Slice bytes from a start index to an end index.

function _sliceBytes(bytes memory data, uint256 start, uint256 end) private pure returns (bytes memory slicedBytes);

Parameters

Name	Type	Description
`data`	`bytes`	The bytes array to slice
`start`	`uint256`	The start index to slice at.
`end`	`uint256`	The end index to slice at.

Errors