SelfPeggingAsset
Inherits: Initializable, ReentrancyGuardUpgradeable, OwnableUpgradeable
Author: Nuts Finance Developer
The SelfPeggingAsset pool provides a way to swap between different tokens
The SelfPeggingAsset contract allows users to trade between different tokens, with prices determined algorithmically based on the current supply and demand of each token
State Variables
FEE_DENOMINATOR
This is the denominator used for calculating transaction fees in the SelfPeggingAsset contract.
uint256 private constant FEE_DENOMINATOR = 10 ** 10;
DEFAULT_FEE_ERROR_MARGIN
This is the maximum error margin for calculating transaction fees in the SelfPeggingAsset contract.
uint256 private constant DEFAULT_FEE_ERROR_MARGIN = 100_000;
DEFAULT_YIELD_ERROR_MARGIN
This is the maximum error margin for calculating transaction yield in the SelfPeggingAsset contract.
uint256 private constant DEFAULT_YIELD_ERROR_MARGIN = 10_000;
DEFAULT_MAX_DELTA_D
This is the maximum error margin for updating A in the SelfPeggingAsset contract.
uint256 private constant DEFAULT_MAX_DELTA_D = 100_000;
MAX_A
This is the maximum value of the amplification coefficient A.
uint256 private constant MAX_A = 10 ** 6;
INITIAL_MINT_MIN
This is minimum initial mint
uint256 private constant INITIAL_MINT_MIN = 100_000;
tokens
This is an array of addresses representing the tokens currently supported by the SelfPeggingAsset contract.
address[] public tokens;
precisions
This is an array of uint256 values representing the precisions of each token in the SelfPeggingAsset contract. The precision of each token is calculated as 10 ** (18 - token decimals).
uint256[] public precisions;
balances
This is an array of uint256 values representing the current balances of each token in the SelfPeggingAsset contract. The balances are converted to the standard token unit (10 ** 18).
uint256[] public balances;
mintFee
This is the fee charged for adding liquidity to the SelfPeggingAsset contract.
uint256 public mintFee;
swapFee
This is the fee charged for trading assets in the SelfPeggingAsset contract. swapFee = swapFee * FEE_DENOMINATOR
uint256 public swapFee;
redeemFee
This is the fee charged for removing liquidity from the SelfPeggingAsset contract. redeemFee = redeemFee * FEE_DENOMINATOR
uint256 public redeemFee;
offPegFeeMultiplier
This is the off peg fee multiplier. offPegFeeMultiplier = offPegFeeMultiplier * FEE_DENOMINATOR
uint256 public offPegFeeMultiplier;
poolToken
This is the address of the ERC20 token contract that represents the SelfPeggingAsset pool token.
ILPToken public poolToken;
totalSupply
The total supply of pool token minted by the swap. It might be different from the pool token supply as the pool token can have multiple minters.
uint256 public totalSupply;
admins
This is a mapping of accounts that have administrative privileges over the SelfPeggingAsset contract.
mapping(address => bool) public admins;
paused
This is a state variable that represents whether or not the SelfPeggingAsset contract is currently paused.
bool public paused;
A
These is a state variables that represents the amplification coefficient A.
uint256 public A;
exchangeRateProviders
Exchange rate provider for the tokens
IExchangeRateProvider[] public exchangeRateProviders;
feeErrorMargin
Fee error margin.
uint256 public feeErrorMargin;
yieldErrorMargin
Yield error margin.
uint256 public yieldErrorMargin;
maxDeltaD
Max delta D.
uint256 public maxDeltaD;
Functions
initialize
Initializes the SelfPeggingAsset contract with the given parameters.
function initialize(
address[] memory _tokens,
uint256[] memory _precisions,
uint256[] memory _fees,
uint256 _offPegFeeMultiplier,
ILPToken _poolToken,
uint256 _A,
IExchangeRateProvider[] memory _exchangeRateProviders
)
public
initializer;
Parameters
| Name | Type | Description |
|---|---|---|
_tokens | address[] | The tokens in the pool. |
_precisions | uint256[] | The precisions of each token (10 ** (18 - token decimals)). |
_fees | uint256[] | The fees for minting, swapping, and redeeming. |
_offPegFeeMultiplier | uint256 | The off peg fee multiplier. |
_poolToken | ILPToken | The address of the pool token. |
_A | uint256 | The initial value of the amplification coefficient A for the pool. |
_exchangeRateProviders | IExchangeRateProvider[] |
mint
Mints new pool token.
function mint(uint256[] calldata _amounts, uint256 _minMintAmount) external nonReentrant returns (uint256);
Parameters
| Name | Type | Description |
|---|---|---|
_amounts | uint256[] | Unconverted token balances used to mint pool token. |
_minMintAmount | uint256 | Minimum amount of pool token to mint. |
Returns
| Name | Type | Description |
|---|---|---|
<none> | uint256 | The amount of pool tokens minted. |
swap
Exchange between two underlying tokens.
function swap(uint256 _i, uint256 _j, uint256 _dx, uint256 _minDy) external nonReentrant returns (uint256);
Parameters
| Name | Type | Description |
|---|---|---|
_i | uint256 | Token index to swap in. |
_j | uint256 | Token index to swap out. |
_dx | uint256 | Unconverted amount of token _i to swap in. |
_minDy | uint256 | Minimum token _j to swap out in converted balance. |
Returns
| Name | Type | Description |
|---|---|---|
<none> | uint256 | Amount of swap out. |
redeemProportion
Redeems pool token to underlying tokens proportionally.
function redeemProportion(
uint256 _amount,
uint256[] calldata _minRedeemAmounts
)
external
nonReentrant
returns (uint256[] memory);
Parameters
| Name | Type | Description |
|---|---|---|
_amount | uint256 | Amount of pool token to redeem. |
_minRedeemAmounts | uint256[] | Minimum amount of underlying tokens to get. |
Returns
| Name | Type | Description |
|---|---|---|
<none> | uint256[] | An array of the amounts of each token to redeem. |
redeemSingle
Redeem pool token to one specific underlying token.
function redeemSingle(uint256 _amount, uint256 _i, uint256 _minRedeemAmount) external nonReentrant returns (uint256);
Parameters
| Name | Type | Description |
|---|---|---|
_amount | uint256 | Amount of pool token to redeem. |
_i | uint256 | Index of the token to redeem to. |
_minRedeemAmount | uint256 | Minimum amount of the underlying token to redeem to. |
Returns
| Name | Type | Description |
|---|---|---|
<none> | uint256 | Amount received. |
redeemMulti
Redeems underlying tokens.
function redeemMulti(
uint256[] calldata _amounts,
uint256 _maxRedeemAmount
)
external
nonReentrant
returns (uint256[] memory);
Parameters
| Name | Type | Description |
|---|---|---|
_amounts | uint256[] | Amounts of underlying tokens to redeem to. |
_maxRedeemAmount | uint256 | Maximum of pool token to redeem. |
Returns
| Name | Type | Description |
|---|---|---|
<none> | uint256[] | Amounts received. |
setMintFee
Updates the mint fee.
function setMintFee(uint256 _mintFee) external onlyOwner;
Parameters
| Name | Type | Description |
|---|---|---|
_mintFee | uint256 | The new mint fee. |
setSwapFee
Updates the swap fee.
function setSwapFee(uint256 _swapFee) external onlyOwner;
Parameters
| Name | Type | Description |
|---|---|---|
_swapFee | uint256 | The new swap fee. |
setRedeemFee
Updates the redeem fee.
function setRedeemFee(uint256 _redeemFee) external onlyOwner;
Parameters
| Name | Type | Description |
|---|---|---|
_redeemFee | uint256 | The new redeem fee. |
setOffPegFeeMultiplier
Updates the off peg fee multiplier.
function setOffPegFeeMultiplier(uint256 _offPegFeeMultiplier) external onlyOwner;
Parameters
| Name | Type | Description |
|---|---|---|
_offPegFeeMultiplier | uint256 | The new off peg fee multiplier. |
pause
Pause mint/swap/redeem actions. Can unpause later.
function pause() external;
unpause
Unpause mint/swap/redeem actions.
function unpause() external;
setAdmin
Updates the admin role for the address.
function setAdmin(address _account, bool _allowed) external onlyOwner;
Parameters
| Name | Type | Description |
|---|---|---|
_account | address | Address to update admin role. |
_allowed | bool | Whether the address is granted the admin role. |
updateA
Update the A value.
function updateA(uint256 _A) external onlyOwner;
Parameters
| Name | Type | Description |
|---|---|---|
_A | uint256 | The new A value. |
donateD
Update the exchange rate provider for the token.
function donateD(uint256[] calldata _amounts, uint256 _minDonationAmount) external nonReentrant returns (uint256);
updateFeeErrorMargin
update fee error margin.
function updateFeeErrorMargin(uint256 newValue) external onlyOwner;
updateYieldErrorMargin
update yield error margin.
function updateYieldErrorMargin(uint256 newValue) external onlyOwner;
updateMaxDeltaDMargin
update yield error margin.
function updateMaxDeltaDMargin(uint256 newValue) external onlyOwner;
distributeLoss
Distribute losses by rebasing negatively
function distributeLoss() external onlyOwner;
rebase
This function allows to rebase LPToken by increasing his total supply from the current stableSwap pool by the staking rewards and the swap fee.
function rebase() external returns (uint256);
getRedeemSingleAmount
Computes the amount when redeeming pool token to one specific underlying token.
function getRedeemSingleAmount(uint256 _amount, uint256 _i) external view returns (uint256, uint256);
Parameters
| Name | Type | Description |
|---|---|---|
_amount | uint256 | Amount of pool token to redeem. |
_i | uint256 | Index of the underlying token to redeem to. |
Returns
| Name | Type | Description |
|---|---|---|
<none> | uint256 | The amount of single token that will be redeemed. |
<none> | uint256 | The amount of pool token charged for redemption fee. |
getRedeemMultiAmount
Compute the amount of pool token that needs to be redeemed.
function getRedeemMultiAmount(uint256[] calldata _amounts) external view returns (uint256, uint256);
Parameters
| Name | Type | Description |
|---|---|---|
_amounts | uint256[] | Unconverted token balances. |
Returns
| Name | Type | Description |
|---|---|---|
<none> | uint256 | The amount of pool token that needs to be redeemed. |
<none> | uint256 | The amount of pool token charged for redemption fee. |
getMintAmount
Compute the amount of pool token that can be minted.
function getMintAmount(uint256[] calldata _amounts) external view returns (uint256, uint256);
Parameters
| Name | Type | Description |
|---|---|---|
_amounts | uint256[] | Unconverted token balances. |
Returns
| Name | Type | Description |
|---|---|---|
<none> | uint256 | The amount of pool tokens to be minted. |
<none> | uint256 | The amount of fees charged. |
getSwapAmount
Computes the output amount after the swap.
function getSwapAmount(uint256 _i, uint256 _j, uint256 _dx) external view returns (uint256, uint256);
Parameters
| Name | Type | Description |
|---|---|---|
_i | uint256 | Token index to swap in. |
_j | uint256 | Token index to swap out. |
_dx | uint256 | Unconverted amount of token _i to swap in. |
Returns
| Name | Type | Description |
|---|---|---|
<none> | uint256 | Unconverted amount of token _j to swap out. |
<none> | uint256 | The amount of fees charged. |
getRedeemProportionAmount
Computes the amounts of underlying tokens when redeeming pool token.
function getRedeemProportionAmount(uint256 _amount) external view returns (uint256[] memory, uint256);
Parameters
| Name | Type | Description |
|---|---|---|
_amount | uint256 | Amount of pool tokens to redeem. |
Returns
| Name | Type | Description |
|---|---|---|
<none> | uint256[] | An array of the amounts of each token to redeem. |
<none> | uint256 | The amount of fee charged |
getTokens
Returns the array of token addresses in the pool.
function getTokens() external view returns (address[] memory);
collectFeeOrYield
Collect fee or yield based on the token balance difference.
function collectFeeOrYield(bool isFee) internal returns (uint256);
Parameters
| Name | Type | Description |
|---|---|---|
isFee | bool | Whether to collect fee or yield. |
Returns
| Name | Type | Description |
|---|---|---|
<none> | uint256 | The amount of fee or yield collected. |
getUpdatedBalancesAndD
Return the amount of fee that's not collected.
function getUpdatedBalancesAndD() internal view returns (uint256[] memory, uint256);
Returns
| Name | Type | Description |
|---|---|---|
<none> | uint256[] | The balances of underlying tokens. |
<none> | uint256 | The total supply of pool tokens. |
_getD
Computes D given token balances.
function _getD(uint256[] memory _balances) internal view returns (uint256);
Parameters
| Name | Type | Description |
|---|---|---|
_balances | uint256[] | Normalized balance of each token. |
Returns
| Name | Type | Description |
|---|---|---|
<none> | uint256 | D The SelfPeggingAsset invariant. |
_getY
Computes token balance given D.
function _getY(uint256[] memory _balances, uint256 _j, uint256 _D) internal view returns (uint256);
Parameters
| Name | Type | Description |
|---|---|---|
_balances | uint256[] | Converted balance of each token except token with index _j. |
_j | uint256 | Index of the token to calculate balance. |
_D | uint256 | The target D value. |
Returns
| Name | Type | Description |
|---|---|---|
<none> | uint256 | Converted balance of the token with index _j. |
_dynamicFee
Calculates the dynamic fee based on liquidity imbalances.
function _dynamicFee(uint256 xpi, uint256 xpj, uint256 _fee) internal view returns (uint256);
Parameters
| Name | Type | Description |
|---|---|---|
xpi | uint256 | The liquidity before or first asset liqidity. |
xpj | uint256 | The liqduity after or second asset liquidity. |
_fee | uint256 | The base fee value. |
Returns
| Name | Type | Description |
|---|---|---|
<none> | uint256 | The dynamically adjusted fee. |
Events
TokenSwapped
This event is emitted when a token swap occurs.
event TokenSwapped(address indexed buyer, uint256 swapAmount, uint256[] amounts, uint256 feeAmount);
Parameters
| Name | Type | Description |
|---|---|---|
buyer | address | is the address of the account that made the swap. |
swapAmount | uint256 | is the amount of the token swapped by the buyer. |
amounts | uint256[] | is an array containing the amounts of each token received by the buyer. |
feeAmount | uint256 | is the amount of transaction fee charged for the swap. |
Minted
This event is emitted when liquidity is added to the SelfPeggingAsset contract.
event Minted(address indexed provider, uint256 mintAmount, uint256[] amounts, uint256 feeAmount);
Parameters
| Name | Type | Description |
|---|---|---|
provider | address | is the address of the liquidity provider. |
mintAmount | uint256 | is the amount of liquidity tokens minted to the provider in exchange for their contribution. |
amounts | uint256[] | is an array containing the amounts of each token contributed by the provider. |
feeAmount | uint256 | is the amount of transaction fee charged for the liquidity provision. |
Donated
This event is emitted when liquidity is added to the SelfPeggingAsset contract.
event Donated(address indexed provider, uint256 mintAmount, uint256[] amounts);
Parameters
| Name | Type | Description |
|---|---|---|
provider | address | is the address of the liquidity provider. |
mintAmount | uint256 | is the amount of liquidity tokens minted to the provider in exchange for their contribution. |
amounts | uint256[] | is an array containing the amounts of each token contributed by the provider. |
Redeemed
This event is emitted when liquidity is removed from the SelfPeggingAsset contract.
event Redeemed(address indexed provider, uint256 redeemAmount, uint256[] amounts, uint256 feeAmount);
Parameters
| Name | Type | Description |
|---|---|---|
provider | address | is the address of the liquidity provider. |
redeemAmount | uint256 | is the amount of liquidity tokens redeemed by the provider. |
amounts | uint256[] | is an array containing the amounts of each token received by the provider. |
feeAmount | uint256 | is the amount of transaction fee charged for the liquidity provision. |
FeeCollected
This event is emitted when transaction fees are collected by the SelfPeggingAsset contract.
event FeeCollected(uint256 feeAmount, uint256 totalSupply);
Parameters
| Name | Type | Description |
|---|---|---|
feeAmount | uint256 | is the amount of fee collected. |
totalSupply | uint256 | is the total supply of LP token. |
YieldCollected
This event is emitted when yield is collected by the SelfPeggingAsset contract.
event YieldCollected(uint256 feeAmount, uint256 totalSupply);
Parameters
| Name | Type | Description |
|---|---|---|
feeAmount | uint256 | is the amount of yield collected. |
totalSupply | uint256 | is the total supply of LP token. |
AModified
This event is emitted when the A parameter is modified.
event AModified(uint256 A);
Parameters
| Name | Type | Description |
|---|---|---|
A | uint256 | is the new value of the A parameter. |
MintFeeModified
This event is emitted when the mint fee is modified.
event MintFeeModified(uint256 mintFee);
Parameters
| Name | Type | Description |
|---|---|---|
mintFee | uint256 | is the new value of the mint fee. |
SwapFeeModified
This event is emitted when the swap fee is modified.
event SwapFeeModified(uint256 swapFee);
Parameters
| Name | Type | Description |
|---|---|---|
swapFee | uint256 | is the new value of the swap fee. |
RedeemFeeModified
This event is emitted when the redeem fee is modified.
event RedeemFeeModified(uint256 redeemFee);
Parameters
| Name | Type | Description |
|---|---|---|
redeemFee | uint256 | is the new value of the redeem fee. |
OffPegFeeMultiplierModified
This event is emitted when the off peg fee multiplier is modified.
event OffPegFeeMultiplierModified(uint256 offPegFeeMultiplier);
Parameters
| Name | Type | Description |
|---|---|---|
offPegFeeMultiplier | uint256 | is the new value of the off peg fee multiplier. |
FeeMarginModified
This event is emitted when the fee margin is modified.
event FeeMarginModified(uint256 margin);
Parameters
| Name | Type | Description |
|---|---|---|
margin | uint256 | is the new value of the margin. |
YieldMarginModified
This event is emitted when the fee margin is modified.
event YieldMarginModified(uint256 margin);
Parameters
| Name | Type | Description |
|---|---|---|
margin | uint256 | is the new value of the margin. |
MaxDeltaDModified
This event is emitted when the max delta D is modified.
event MaxDeltaDModified(uint256 delta);
Parameters
| Name | Type | Description |
|---|---|---|
delta | uint256 | is the new value of the delta. |
Errors
InputMismatch
Error thrown when the input parameters do not match the expected values.
error InputMismatch();
NoFees
Error thrown when fees are not set
error NoFees();
FeePercentageTooLarge
Error thrown when the fee percentage is too large.
error FeePercentageTooLarge();
TokenNotSet
Error thrown when the token address is not set.
error TokenNotSet();
ExchangeRateProviderNotSet
Error thrown when the exchange rate provider is not set.
error ExchangeRateProviderNotSet();
PrecisionNotSet
Error thrown when the precision is not set.
error PrecisionNotSet();
DuplicateToken
Error thrown when the tokens are duplicates.
error DuplicateToken();
PoolTokenNotSet
Error thrown when the pool token is not set.
error PoolTokenNotSet();
ANotSet
Error thrown when the A value is not set.
error ANotSet();
InvalidAmount
Error thrown when the amount is invalid.
error InvalidAmount();
Paused
Error thrown when the pool is paused.
error Paused();
ZeroAmount
Error thrown when the amount is zero.
error ZeroAmount();
SameToken
Error thrown when the token is the same.
error SameToken();
InvalidIn
Error thrown when the input token is invalid.
error InvalidIn();
InvalidOut
Error thrown when the output token is invalid.
error InvalidOut();
InvalidMins
Error thrown when the amount is invalid.
error InvalidMins();
InvalidToken
Error thrown when the token is invalid.
error InvalidToken();
LimitExceeded
Error thrown when the limit is exceeded.
error LimitExceeded();
NotPaused
Error thrown when the pool is not paused.
error NotPaused();
AccountIsZero
Error thrown when the account address is zero
error AccountIsZero();
PastBlock
Error thrown when the block number is an past block
error PastBlock();
NoLosses
Error thrown when there is no loss
error NoLosses();
NotAdmin
Error thrown when the account is not an admin
error NotAdmin();
InsufficientDonationAmount
Error thrown donation amount is insufficient
error InsufficientDonationAmount();
InsufficientMintAmount
Error thrown insufficient mint amount
error InsufficientMintAmount(uint256 mintAmount, uint256 minMintAmount);
InsufficientSwapOutAmount
Error thrown insufficient swap out amount
error InsufficientSwapOutAmount(uint256 outAmount, uint256 minOutAmount);
InsufficientRedeemAmount
Error thrown insufficient redeem amount
error InsufficientRedeemAmount(uint256 redeemAmount, uint256 minRedeemAmount);
MaxRedeemAmount
Error thrown when redeem amount is max
error MaxRedeemAmount(uint256 redeemAmount, uint256 maxRedeemAmount);
SameTokenInTokenOut
Error thrown in and out token are the same
error SameTokenInTokenOut(uint256 tokenInIndex, uint256 tokenOutIndex);
ImbalancedPool
Error thrown when the pool is imbalanced
error ImbalancedPool(uint256 oldD, uint256 newD);