OracleHelper

Git Source

Author:
Trader Joe

This library contains functions to manage the oracle
The oracle samples are stored in a single bytes32 array.
Each sample is encoded as follows:
0 - 16: oracle length (16 bits)
16 - 80: cumulative id (64 bits)
80 - 144: cumulative volatility accumulator (64 bits)
144 - 208: cumulative bin crossed (64 bits)
208 - 216: sample lifetime (8 bits)
216 - 256: sample creation timestamp (40 bits)

State Variables

_MAX_SAMPLE_LIFETIME

uint256 internal constant _MAX_SAMPLE_LIFETIME = 120 seconds;

Functions

checkOracleId

Modifier to check that the oracle id is valid

modifier checkOracleId(uint16 oracleId);

Parameters

Name	Type	Description
oracleId	uint16	The oracle id

getSample

Returns the sample at the given oracleId

function getSample(Oracle storage oracle, uint16 oracleId)
    internal
    view
    checkOracleId(oracleId)
    returns (bytes32 sample);

Parameters

Name	Type	Description
oracle	Oracle	The oracle
oracleId	uint16	The oracle id

Returns

Name	Type	Description
sample	bytes32	The sample

getActiveSampleAndSize

Returns the active sample and the active size of the oracle

function getActiveSampleAndSize(Oracle storage oracle, uint16 oracleId)
    internal
    view
    returns (bytes32 activeSample, uint16 activeSize);

Parameters

Name	Type	Description
oracle	Oracle	The oracle
oracleId	uint16	The oracle id

Returns

Name	Type	Description
activeSample	bytes32	The active sample
activeSize	uint16	The active size of the oracle

getSampleAt

Returns the sample at the given timestamp. If the timestamp is not in the oracle, it returns the closest sample

function getSampleAt(Oracle storage oracle, uint16 oracleId, uint40 lookUpTimestamp)
    internal
    view
    returns (uint40 lastUpdate, uint64 cumulativeId, uint64 cumulativeVolatility, uint64 cumulativeBinCrossed);

Parameters

Name	Type	Description
oracle	Oracle	The oracle
oracleId	uint16	The oracle id
lookUpTimestamp	uint40	The timestamp to look up

Returns

Name	Type	Description
lastUpdate	uint40	The last update timestamp
cumulativeId	uint64	The cumulative id
cumulativeVolatility	uint64	The cumulative volatility
cumulativeBinCrossed	uint64	The cumulative bin crossed

binarySearch

Binary search to find the 2 samples surrounding the given timestamp

function binarySearch(Oracle storage oracle, uint16 oracleId, uint40 lookUpTimestamp, uint16 length)
    internal
    view
    returns (bytes32, bytes32);

Parameters

Name	Type	Description
oracle	Oracle	The oracle
oracleId	uint16	The oracle id
lookUpTimestamp	uint40	The timestamp to look up
length	uint16	The oracle length

Returns

Name	Type	Description
<none>	bytes32	prevSample The previous sample
<none>	bytes32	nextSample The next sample

setSample

Sets the sample at the given oracleId

function setSample(Oracle storage oracle, uint16 oracleId, bytes32 sample) internal checkOracleId(oracleId);

Parameters

Name	Type	Description
oracle	Oracle	The oracle
oracleId	uint16	The oracle id
sample	bytes32	The sample

update

Updates the oracle

function update(Oracle storage oracle, bytes32 parameters, uint24 activeId) internal returns (bytes32);

Parameters

Name	Type	Description
oracle	Oracle	The oracle
parameters	bytes32	The parameters
activeId	uint24	The active id

Returns

Name	Type	Description
<none>	bytes32	The updated parameters

increaseLength

Increases the oracle length

function increaseLength(Oracle storage oracle, uint16 oracleId, uint16 newLength) internal;

Parameters

Name	Type	Description
oracle	Oracle	The oracle
oracleId	uint16	The oracle id
newLength	uint16	The new length

_checkOracleId

Checks that the oracle id is valid

function _checkOracleId(uint16 oracleId) private pure;

Parameters

Name	Type	Description
oracleId	uint16	The oracle id

Errors

OracleHelper__InvalidOracleId

error OracleHelper__InvalidOracleId();

OracleHelper__NewLengthTooSmall

error OracleHelper__NewLengthTooSmall();

OracleHelper__LookUpTimestampTooOld

error OracleHelper__LookUpTimestampTooOld();

Structs

Oracle

struct Oracle {
    bytes32[65535] samples;
}