Elastic Peripheral Library Contracts

AntiSnipingAttack​

The motivation and explanation of the mechanism can be found here. The function containing the bulk of the logic is update().

Struct: Data​

Field	Type	Formula Variable	Explanation
lastActionTime	uint32	$t_{last}$	timestamp of last action performed
lockTime	uint32	$t_{lock}$	average start time of lock schedule
unlockTime	uint32	$t_{unlock}$	average unlock time of locked fees
feesLocked	uint32	$fee_{locked}$	locked rToken qty since last update

initialize()​

Initializes Data values for a new position. The time variables are set to the current timestamp, while feesLocked is set to zero.

update()​

Updates Data values for an existing position. Calculates the amount of claimable reinvestment tokens to be sent to the user and, in the case of liquidity removal, the amount of burnable reinvestment tokens as well.

Formula​

$claimBps_{new} = min(BPS, \frac{t_{now}-t_{lock}}{t_{target}})$

$claimBps_{current} = min(BPS, \frac{t_{now}-t_{last}}{t_{unlock} - t_{target}})$

if $t_{unlock} > t_{target}$, $BPS$ otherwise $fee_{harvest}$ and $fee_{lock}$ updated through calcFeeProportions()

$t_{unlock} = \frac{(t_{lock} + t_{target}) * (BPS - claimBps_{new}) * fee_{collect} + t_{unlock} * (BPS - claimBps_{current}) * fee_{locked}}{fee_{lock} * BPS}$

• If adding liquidity, update $t_{lock} = ceil(\frac{max(t_{lock}, t_{now} - t_{target})*L + t_{now} * \Delta{L}}{L + \Delta{L}})$

• If removing liquidity,

  • $fee_{burn} = fee_{harvest} * \frac{\Delta{L}}{L}$

  • $fee_{harvest}$ -= $fee_{burn}$

Input​

Field	Type	Formula Variable	Explanation
self	Data	N.A.	stored data values for an existing position
currentLiquidity	uint128	$L$	current position liquidity
liquidityDelta	uint128	$\Delta{L}$	quantity change to be applied
currentTime	uint32	$t_{now}$	current block timestamp
isAddLiquidity	bool	N.A.	true = add liquidity, false = remove liquidity
feesSinceLastAction	uint256	$fee_{collect}$	fees accrued since last action
vestingPeriod	uint256	$t_{target}$	maximum time duration for which LP fees are proportionally burnt upon LP removals

Output​

Field	Type	Formula Variable	Explanation
feesClaimable	uint256	$fee_{harvest}$	claimable reinvestment token amount
feesBurnable	uint256	$fee_{burn}$	reinvestment token amount to burn

calcFeeProportions()​

Calculates the proportion of locked fees and claimable fees given the fee amounts and claimable fee basis points.

Formula​

$fee_{harvest} = \frac{claimBps_{current}}{BPS} * fee_{locked} + \frac{claimBps_{new}}{BPS} * fee_{collect}$ $fee_{lock} = fee_{locked} + fee_{collect} - fee_{harvest}$

Input​

Field	Type	Formula Variable	Explanation
currentFees	uint256	$fee_{locked}$	currently locked fees
nextFees	uint256	$fee_{collect}$	fees since last action
currentClaimableBps	uint256	$claimBps_{current}$	proportion of claimable / unlocked currentFees in basis points
nextClaimableBps	uint256	$claimBps_{new}$	proportion of claimable nextFees in basis points

Output​

Field	Type	Formula Variable	Explanation
feesLockedNew	uint256	$fee_{lock}$	new fee amount to be locked
feesClaimable	uint256	$fee_{harvest}$	claimable fees to be sent to user

BytesLib​

Solidity Bytes Arrays Utils @author Gonçalo Sá [e-mail]

Bytes tightly packed arrays utility library for ethereum contracts written in Solidity. The library lets you slice and type cast bytes arrays both in memory and storage.

LiquidityMath​

Contract to calculate the expected amount of liquidity given the amounts of tokens.

getLiquidityFromQty0()​

Params:
    uint160 lowerSqrtP     // a lower sqrt price of the position
    uint160 upperSqrtP     // a upper sqrt price of the position
    uint256 qty0           // the amount of token0 to add
Returns:
    uint128 liquidity       // amount of liquidity to receive

Get liquidity from qty0 of the first token given the price range.

getLiquidityFromQty1()​

Params:
    uint160 lowerSqrtP     // a lower sqrt price of the position
    uint160 upperSqrtP     // a upper sqrt price of the position
    uint256 qty1           // the amount of token1 to add
Returns:
    uint128 liquidity       // amount of liquidity to receive

Get liquidity from qty1 of the second token given the price range.

getLiquidityFromQties()​

Params:
    uint160 currentSqrtP    // the current price, e.g the pool's current price
    uint160 lowerSqrtP      // a lower sqrt price of the position
    uint160 upperSqrtP      // a upper sqrt price of the position
    uint256 qty0            // the amount of token0 to add
    uint256 qty1            // the amount of token1 to add
Returns:
    uint128 liquidity       // amount of liquidity to receive

Get liquidity given the price range and amounts of 2 tokens

PathHelper​

Functions for manipulating path data for multihop swaps

Variables​

ADDR_SIZE = 20 // length of the address, i.e 20 bytes
FEE_SIZE = 2 // length of the fee, i.e 2 bytes
TOKEN_AND_POOL_OFFSET = ADDR_SIZE + FEE_SIZE// the offset of a single token address + pool fee
POOL_DATA_OFFSET = TOKEN_AND_POOL_OFFSET + ADDR_SIZE // the offset of 2 token addresses + pool fee
MULTIPLE_POOLS_MIN_LENGTH = POOL_DATA_OFFSET + TOKEN_AND_POOL_OFFSET // min length that contains at least 2 pools

hasMultiplePools()​

Params:
    bytes path
Returns:
    bool

Return true if the path contains 2 or more pools, false otherwise

numPools()​

Params:
    bytes path
Returns:
    uint256

Returns the number of pools in the path.

decodeFirstPool()​

Params:
    bytes path
Returns:
    address tokenA
    address tokenB
    uint16 fee

Return the first pool's data from the path, including tokenA, tokenB and fee.

getFirstPool()​

Params:
    bytes path
Returns:
    bytes data

Return the segment corresponding to the first pool in the path.

skipToken()​

Params:
    bytes path
Returns:
    bytes newPath

Skip a token + fee from the buffer and returns the remainder.

PoolAddress​

Provides a function for deriving a pool address from the factory, tokens, and swap fee

computeAddress()​

Params:
    address factory   // DMMv2 factory contract
    address token0    // the first token of the pool
    address token1    // the second token of the pool
    uint16 swapFee    // the fee of the pool
    bytes32 poolInitHash    // the keccake256 hash of the Pool creation code
Returns:
    address pool    // the pool address

Deterministically computes the pool address from the given data.

PoolTicksCounter​

countInitializedTicksCrossed()​

Params:
    IProAMMPool
    int24 nearestCurrentTickBefore
    int24 nearestCurrentTickAfter
Returns:
    uint32 initializedTicksCrossed

Count the number of initialized ticks have been crossed given the previous/current nearest initialized ticks to the current tick.

TokenHelper​

A helper contract to transfer token/ETH.

transferToken()​

Params:
    IERC20 token
    uint256 amount
    address sender
    address receiver

Transfer an amount of ERC20 token from the sender to the receiver.

transferEth()​

Params:
    uint256 amount
    address receiver

Transfer an amount of ETH to the receiver.