PredicateLibrary

State Variables

string constant PREDICATE_TYPE = "Predicate(uint8 predicateType,bytes data)";

bytes32 constant PREDICATE_TYPEHASH = keccak256(bytes(PREDICATE_TYPE));

Creates a digest match predicate.

function createDigestMatchPredicate(bytes32 imageId, bytes32 hash) internal pure returns (Predicate memory);

Parameters

Name	Type	Description
`imageId`	`bytes32`
`hash`	`bytes32`	The hash to match.

Returns

Name	Type	Description
`<none>`	`Predicate`	A Predicate struct with type DigestMatch and the provided hash.

Creates a prefix match predicate.

function createPrefixMatchPredicate(bytes32 imageId, bytes memory prefix) internal pure returns (Predicate memory);

Parameters

Name	Type	Description
`imageId`	`bytes32`
`prefix`	`bytes`	The prefix to match.

Returns

Name	Type	Description
`<none>`	`Predicate`	A Predicate struct with type PrefixMatch and the provided prefix.

Creates a claim digest match predicate.

function createClaimDigestMatchPredicate(bytes32 claimDigest) internal pure returns (Predicate memory);

Parameters

Name	Type	Description
`claimDigest`	`bytes32`	The claimDigest to match.

Returns

Name	Type	Description
`<none>`	`Predicate`	A Predicate struct with type ClaimDigestMatch and the provided claimDigest.

Evaluates the predicate against the given journal and journal digest.

function eval(Predicate memory predicate, bytes32 imageId, bytes memory journal, bytes32 journalDigest)
    internal
    pure
    returns (bool);

Parameters

Name	Type	Description
`predicate`	`Predicate`	The predicate to evaluate.
`imageId`	`bytes32`
`journal`	`bytes`	The journal to evaluate against.
`journalDigest`	`bytes32`	The digest of the journal.

Returns

Name	Type	Description
`<none>`	`bool`	True if the predicate is satisfied, false otherwise.

Checks if the journal starts with the given prefix.

function startsWith(bytes memory journal, bytes memory prefix) internal pure returns (bool);

Parameters

Name	Type	Description
`journal`	`bytes`	The journal to check.
`prefix`	`bytes`	The prefix to check for.

Returns

Name	Type	Description
`<none>`	`bool`	True if the journal starts with the prefix, false otherwise.

Computes the EIP-712 digest for the given predicate.

function eip712Digest(Predicate memory predicate) internal pure returns (bytes32);

Parameters

Name	Type	Description
`predicate`	`Predicate`	The predicate to compute the digest for.

Returns

Name	Type	Description
`<none>`	`bytes32`	The EIP-712 digest of the predicate.