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ERC-20
Overview
Max Total Supply
747,232.804623598139285851 mkcrvUSD-f
Holders
23
Market
Onchain Market Cap
$0.00
Circulating Supply Market Cap
-
Other Info
Token Contract (WITH 18 Decimals)
Balance
0 mkcrvUSD-fValue
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# | Exchange | Pair | Price | 24H Volume | % Volume |
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Minimal Proxy Contract for 0x67fe41a94e779ccfa22cff02cc2957dc9c0e4286
Similar Match Source Code This contract matches the deployed Bytecode of the Source Code for Contract 0xb9f861B7...3607b1f24 The constructor portion of the code might be different and could alter the actual behaviour of the contract
Contract Name:
Vyper_contract
Compiler Version
vyper:0.3.7
Contract Source Code (Vyper language format)
# @version 0.3.7 """ @title StableSwap @author Curve.Fi @license Copyright (c) Curve.Fi, 2020-2023 - all rights reserved @notice 2 coin pool implementation with no lending @dev ERC20 support for return True/revert, return True/False, return None """ from vyper.interfaces import ERC20 interface Factory: def get_fee_receiver(_pool: address) -> address: view def admin() -> address: view interface ERC1271: def isValidSignature(_hash: bytes32, _signature: Bytes[65]) -> bytes32: view event Transfer: sender: indexed(address) receiver: indexed(address) value: uint256 event Approval: owner: indexed(address) spender: indexed(address) value: uint256 event TokenExchange: buyer: indexed(address) sold_id: int128 tokens_sold: uint256 bought_id: int128 tokens_bought: uint256 event AddLiquidity: provider: indexed(address) token_amounts: uint256[N_COINS] fees: uint256[N_COINS] invariant: uint256 token_supply: uint256 event RemoveLiquidity: provider: indexed(address) token_amounts: uint256[N_COINS] fees: uint256[N_COINS] token_supply: uint256 event RemoveLiquidityOne: provider: indexed(address) token_amount: uint256 coin_amount: uint256 token_supply: uint256 event RemoveLiquidityImbalance: provider: indexed(address) token_amounts: uint256[N_COINS] fees: uint256[N_COINS] invariant: uint256 token_supply: uint256 event RampA: old_A: uint256 new_A: uint256 initial_time: uint256 future_time: uint256 event StopRampA: A: uint256 t: uint256 event CommitNewFee: new_fee: uint256 event ApplyNewFee: fee: uint256 N_COINS: constant(uint256) = 2 N_COINS_128: constant(int128) = 2 PRECISION: constant(uint256) = 10 ** 18 ADMIN_ACTIONS_DEADLINE_DT: constant(uint256) = 86400 * 3 FEE_DENOMINATOR: constant(uint256) = 10 ** 10 ADMIN_FEE: constant(uint256) = 5000000000 A_PRECISION: constant(uint256) = 100 MAX_FEE: constant(uint256) = 5 * 10 ** 9 MAX_A: constant(uint256) = 10 ** 6 MAX_A_CHANGE: constant(uint256) = 10 MIN_RAMP_TIME: constant(uint256) = 86400 EIP712_TYPEHASH: constant(bytes32) = keccak256("EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)") PERMIT_TYPEHASH: constant(bytes32) = keccak256("Permit(address owner,address spender,uint256 value,uint256 nonce,uint256 deadline)") # keccak256("isValidSignature(bytes32,bytes)")[:4] << 224 ERC1271_MAGIC_VAL: constant(bytes32) = 0x1626ba7e00000000000000000000000000000000000000000000000000000000 VERSION: constant(String[8]) = "v6.0.1" factory: public(address) coins: public(address[N_COINS]) balances: public(uint256[N_COINS]) fee: public(uint256) # fee * 1e10 future_fee: public(uint256) admin_action_deadline: public(uint256) initial_A: public(uint256) future_A: public(uint256) initial_A_time: public(uint256) future_A_time: public(uint256) rate_multipliers: uint256[N_COINS] name: public(String[64]) symbol: public(String[32]) balanceOf: public(HashMap[address, uint256]) allowance: public(HashMap[address, HashMap[address, uint256]]) totalSupply: public(uint256) DOMAIN_SEPARATOR: public(bytes32) nonces: public(HashMap[address, uint256]) last_prices_packed: uint256 # [last_price, ma_price] ma_exp_time: public(uint256) ma_last_time: public(uint256) @external def __init__(): # we do this to prevent the implementation contract from being used as a pool self.factory = 0x0000000000000000000000000000000000000001 assert N_COINS == 2 @external def initialize( _name: String[32], _symbol: String[10], _coins: address[4], _rate_multipliers: uint256[4], _A: uint256, _fee: uint256, ): """ @notice Contract constructor @param _name Name of the new pool @param _symbol Token symbol @param _coins List of all ERC20 conract addresses of coins @param _rate_multipliers List of number of decimals in coins @param _A Amplification coefficient multiplied by n ** (n - 1) @param _fee Fee to charge for exchanges """ # check if factory was already set to prevent initializing contract twice assert self.factory == empty(address) for i in range(N_COINS): coin: address = _coins[i] if coin == empty(address): break self.coins[i] = coin self.rate_multipliers[i] = _rate_multipliers[i] A: uint256 = _A * A_PRECISION self.initial_A = A self.future_A = A self.fee = _fee self.factory = msg.sender self.ma_exp_time = 866 # = 600 / ln(2) self.last_prices_packed = self.pack_prices(10**18, 10**18) self.ma_last_time = block.timestamp name: String[64] = concat("Curve.fi Factory Plain Pool: ", _name) self.name = name self.symbol = concat(_symbol, "-f") self.DOMAIN_SEPARATOR = keccak256( _abi_encode(EIP712_TYPEHASH, keccak256(name), keccak256(VERSION), chain.id, self) ) # fire a transfer event so block explorers identify the contract as an ERC20 log Transfer(empty(address), self, 0) ### ERC20 Functionality ### @view @external def decimals() -> uint8: """ @notice Get the number of decimals for this token @dev Implemented as a view method to reduce gas costs @return uint8 decimal places """ return 18 @internal def _transfer(_from: address, _to: address, _value: uint256): # # NOTE: vyper does not allow underflows # # so the following subtraction would revert on insufficient balance self.balanceOf[_from] -= _value self.balanceOf[_to] += _value log Transfer(_from, _to, _value) @external def transfer(_to : address, _value : uint256) -> bool: """ @dev Transfer token for a specified address @param _to The address to transfer to. @param _value The amount to be transferred. """ self._transfer(msg.sender, _to, _value) return True @external def transferFrom(_from : address, _to : address, _value : uint256) -> bool: """ @dev Transfer tokens from one address to another. @param _from address The address which you want to send tokens from @param _to address The address which you want to transfer to @param _value uint256 the amount of tokens to be transferred """ self._transfer(_from, _to, _value) _allowance: uint256 = self.allowance[_from][msg.sender] if _allowance != max_value(uint256): self.allowance[_from][msg.sender] = _allowance - _value return True @external def approve(_spender : address, _value : uint256) -> bool: """ @notice Approve the passed address to transfer the specified amount of tokens on behalf of msg.sender @dev Beware that changing an allowance via this method brings the risk that someone may use both the old and new allowance by unfortunate transaction ordering: https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729 @param _spender The address which will transfer the funds @param _value The amount of tokens that may be transferred @return bool success """ self.allowance[msg.sender][_spender] = _value log Approval(msg.sender, _spender, _value) return True @external def permit( _owner: address, _spender: address, _value: uint256, _deadline: uint256, _v: uint8, _r: bytes32, _s: bytes32 ) -> bool: """ @notice Approves spender by owner's signature to expend owner's tokens. See https://eips.ethereum.org/EIPS/eip-2612. @dev Inspired by https://github.com/yearn/yearn-vaults/blob/main/contracts/Vault.vy#L753-L793 @dev Supports smart contract wallets which implement ERC1271 https://eips.ethereum.org/EIPS/eip-1271 @param _owner The address which is a source of funds and has signed the Permit. @param _spender The address which is allowed to spend the funds. @param _value The amount of tokens to be spent. @param _deadline The timestamp after which the Permit is no longer valid. @param _v The bytes[64] of the valid secp256k1 signature of permit by owner @param _r The bytes[0:32] of the valid secp256k1 signature of permit by owner @param _s The bytes[32:64] of the valid secp256k1 signature of permit by owner @return True, if transaction completes successfully """ assert _owner != empty(address) assert block.timestamp <= _deadline nonce: uint256 = self.nonces[_owner] digest: bytes32 = keccak256( concat( b"\x19\x01", self.DOMAIN_SEPARATOR, keccak256(_abi_encode(PERMIT_TYPEHASH, _owner, _spender, _value, nonce, _deadline)) ) ) if _owner.is_contract: sig: Bytes[65] = concat(_abi_encode(_r, _s), slice(convert(_v, bytes32), 31, 1)) # reentrancy not a concern since this is a staticcall assert ERC1271(_owner).isValidSignature(digest, sig) == ERC1271_MAGIC_VAL else: assert ecrecover(digest, convert(_v, uint256), convert(_r, uint256), convert(_s, uint256)) == _owner self.allowance[_owner][_spender] = _value self.nonces[_owner] = nonce + 1 log Approval(_owner, _spender, _value) return True ### StableSwap Functionality ### @pure @internal def pack_prices(p1: uint256, p2: uint256) -> uint256: assert p1 < 2**128 assert p2 < 2**128 return p1 | shift(p2, 128) @view @external def last_price() -> uint256: return self.last_prices_packed & (2**128 - 1) @view @external def ema_price() -> uint256: return shift(self.last_prices_packed, -128) @view @external def get_balances() -> uint256[N_COINS]: return self.balances @view @internal def _A() -> uint256: """ Handle ramping A up or down """ t1: uint256 = self.future_A_time A1: uint256 = self.future_A if block.timestamp < t1: A0: uint256 = self.initial_A t0: uint256 = self.initial_A_time # Expressions in uint256 cannot have negative numbers, thus "if" if A1 > A0: return A0 + (A1 - A0) * (block.timestamp - t0) / (t1 - t0) else: return A0 - (A0 - A1) * (block.timestamp - t0) / (t1 - t0) else: # when t1 == 0 or block.timestamp >= t1 return A1 @view @external def admin_fee() -> uint256: return ADMIN_FEE @view @external def A() -> uint256: return self._A() / A_PRECISION @view @external def A_precise() -> uint256: return self._A() @pure @internal def _xp_mem(_rates: uint256[N_COINS], _balances: uint256[N_COINS]) -> uint256[N_COINS]: result: uint256[N_COINS] = empty(uint256[N_COINS]) for i in range(N_COINS): result[i] = _rates[i] * _balances[i] / PRECISION return result @pure @internal def get_D(_xp: uint256[N_COINS], _amp: uint256) -> uint256: """ D invariant calculation in non-overflowing integer operations iteratively A * sum(x_i) * n**n + D = A * D * n**n + D**(n+1) / (n**n * prod(x_i)) Converging solution: D[j+1] = (A * n**n * sum(x_i) - D[j]**(n+1) / (n**n prod(x_i))) / (A * n**n - 1) """ S: uint256 = 0 for x in _xp: S += x if S == 0: return 0 D: uint256 = S Ann: uint256 = _amp * N_COINS for i in range(255): D_P: uint256 = D * D / _xp[0] * D / _xp[1] / N_COINS**N_COINS Dprev: uint256 = D D = (Ann * S / A_PRECISION + D_P * N_COINS) * D / ((Ann - A_PRECISION) * D / A_PRECISION + (N_COINS + 1) * D_P) # Equality with the precision of 1 if D > Dprev: if D - Dprev <= 1: return D else: if Dprev - D <= 1: return D # convergence typically occurs in 4 rounds or less, this should be unreachable! # if it does happen the pool is borked and LPs can withdraw via `remove_liquidity` raise @view @internal def get_D_mem(_rates: uint256[N_COINS], _balances: uint256[N_COINS], _amp: uint256) -> uint256: xp: uint256[N_COINS] = self._xp_mem(_rates, _balances) return self.get_D(xp, _amp) @internal @view def _get_p(xp: uint256[N_COINS], amp: uint256, D: uint256) -> uint256: # dx_0 / dx_1 only, however can have any number of coins in pool ANN: uint256 = amp * N_COINS Dr: uint256 = D / (N_COINS**N_COINS) for i in range(N_COINS): Dr = Dr * D / xp[i] return 10**18 * (ANN * xp[0] / A_PRECISION + Dr * xp[0] / xp[1]) / (ANN * xp[0] / A_PRECISION + Dr) @external @view def get_p() -> uint256: amp: uint256 = self._A() xp: uint256[N_COINS] = self._xp_mem(self.rate_multipliers, self.balances) D: uint256 = self.get_D(xp, amp) return self._get_p(xp, amp, D) @internal @view def exp(power: int256) -> uint256: if power <= -42139678854452767551: return 0 if power >= 135305999368893231589: raise "exp overflow" x: int256 = unsafe_div(unsafe_mul(power, 2**96), 10**18) k: int256 = unsafe_div( unsafe_add( unsafe_div(unsafe_mul(x, 2**96), 54916777467707473351141471128), 2**95), 2**96) x = unsafe_sub(x, unsafe_mul(k, 54916777467707473351141471128)) y: int256 = unsafe_add(x, 1346386616545796478920950773328) y = unsafe_add(unsafe_div(unsafe_mul(y, x), 2**96), 57155421227552351082224309758442) p: int256 = unsafe_sub(unsafe_add(y, x), 94201549194550492254356042504812) p = unsafe_add(unsafe_div(unsafe_mul(p, y), 2**96), 28719021644029726153956944680412240) p = unsafe_add(unsafe_mul(p, x), (4385272521454847904659076985693276 * 2**96)) q: int256 = x - 2855989394907223263936484059900 q = unsafe_add(unsafe_div(unsafe_mul(q, x), 2**96), 50020603652535783019961831881945) q = unsafe_sub(unsafe_div(unsafe_mul(q, x), 2**96), 533845033583426703283633433725380) q = unsafe_add(unsafe_div(unsafe_mul(q, x), 2**96), 3604857256930695427073651918091429) q = unsafe_sub(unsafe_div(unsafe_mul(q, x), 2**96), 14423608567350463180887372962807573) q = unsafe_add(unsafe_div(unsafe_mul(q, x), 2**96), 26449188498355588339934803723976023) return shift( unsafe_mul(convert(unsafe_div(p, q), uint256), 3822833074963236453042738258902158003155416615667), unsafe_sub(k, 195)) @internal @view def _ma_price() -> uint256: ma_last_time: uint256 = self.ma_last_time pp: uint256 = self.last_prices_packed last_price: uint256 = min(pp & (2**128 - 1), 2 * 10**18) last_ema_price: uint256 = shift(pp, -128) if ma_last_time < block.timestamp: alpha: uint256 = self.exp(- convert((block.timestamp - ma_last_time) * 10**18 / self.ma_exp_time, int256)) return (last_price * (10**18 - alpha) + last_ema_price * alpha) / 10**18 else: return last_ema_price @external @view def price_oracle() -> uint256: return self._ma_price() @internal def save_p_from_price(last_price: uint256): """ Saves current price and its EMA """ if last_price != 0: self.last_prices_packed = self.pack_prices(last_price, self._ma_price()) if self.ma_last_time < block.timestamp: self.ma_last_time = block.timestamp @internal def save_p(xp: uint256[N_COINS], amp: uint256, D: uint256): """ Saves current price and its EMA """ self.save_p_from_price(self._get_p(xp, amp, D)) @view @external def get_virtual_price() -> uint256: """ @notice The current virtual price of the pool LP token @dev Useful for calculating profits @return LP token virtual price normalized to 1e18 """ amp: uint256 = self._A() xp: uint256[N_COINS] = self._xp_mem(self.rate_multipliers, self.balances) D: uint256 = self.get_D(xp, amp) # D is in the units similar to DAI (e.g. converted to precision 1e18) # When balanced, D = n * x_u - total virtual value of the portfolio return D * PRECISION / self.totalSupply @view @external def calc_token_amount(_amounts: uint256[N_COINS], _is_deposit: bool) -> uint256: """ @notice Calculate addition or reduction in token supply from a deposit or withdrawal @param _amounts Amount of each coin being deposited @param _is_deposit set True for deposits, False for withdrawals @return Expected amount of LP tokens received """ amp: uint256 = self._A() old_balances: uint256[N_COINS] = self.balances rates: uint256[N_COINS] = self.rate_multipliers # Initial invariant D0: uint256 = self.get_D_mem(rates, old_balances, amp) total_supply: uint256 = self.totalSupply new_balances: uint256[N_COINS] = old_balances for i in range(N_COINS): amount: uint256 = _amounts[i] if _is_deposit: new_balances[i] += amount else: new_balances[i] -= amount # Invariant after change D1: uint256 = self.get_D_mem(rates, new_balances, amp) # We need to recalculate the invariant accounting for fees # to calculate fair user's share D2: uint256 = D1 if total_supply > 0: # Only account for fees if we are not the first to deposit base_fee: uint256 = self.fee * N_COINS / (4 * (N_COINS - 1)) for i in range(N_COINS): ideal_balance: uint256 = D1 * old_balances[i] / D0 difference: uint256 = 0 new_balance: uint256 = new_balances[i] if ideal_balance > new_balance: difference = ideal_balance - new_balance else: difference = new_balance - ideal_balance new_balances[i] -= base_fee * difference / FEE_DENOMINATOR xp: uint256[N_COINS] = self._xp_mem(rates, new_balances) D2 = self.get_D(xp, amp) else: return D1 # Take the dust if there was any diff: uint256 = 0 if _is_deposit: diff = D2 - D0 else: diff = D0 - D2 return diff * total_supply / D0 @external @nonreentrant('lock') def add_liquidity( _amounts: uint256[N_COINS], _min_mint_amount: uint256, _receiver: address = msg.sender ) -> uint256: """ @notice Deposit coins into the pool @param _amounts List of amounts of coins to deposit @param _min_mint_amount Minimum amount of LP tokens to mint from the deposit @param _receiver Address that owns the minted LP tokens @return Amount of LP tokens received by depositing """ amp: uint256 = self._A() old_balances: uint256[N_COINS] = self.balances rates: uint256[N_COINS] = self.rate_multipliers # Initial invariant D0: uint256 = self.get_D_mem(rates, old_balances, amp) total_supply: uint256 = self.totalSupply new_balances: uint256[N_COINS] = old_balances for i in range(N_COINS): amount: uint256 = _amounts[i] if amount > 0: assert ERC20(self.coins[i]).transferFrom(msg.sender, self, amount, default_return_value=True) # dev: failed transfer new_balances[i] += amount else: assert total_supply != 0 # dev: initial deposit requires all coins # Invariant after change D1: uint256 = self.get_D_mem(rates, new_balances, amp) assert D1 > D0 # We need to recalculate the invariant accounting for fees # to calculate fair user's share fees: uint256[N_COINS] = empty(uint256[N_COINS]) mint_amount: uint256 = 0 if total_supply > 0: # Only account for fees if we are not the first to deposit base_fee: uint256 = self.fee * N_COINS / (4 * (N_COINS - 1)) for i in range(N_COINS): ideal_balance: uint256 = D1 * old_balances[i] / D0 difference: uint256 = 0 new_balance: uint256 = new_balances[i] if ideal_balance > new_balance: difference = ideal_balance - new_balance else: difference = new_balance - ideal_balance fees[i] = base_fee * difference / FEE_DENOMINATOR self.balances[i] = new_balance - (fees[i] * ADMIN_FEE / FEE_DENOMINATOR) new_balances[i] -= fees[i] xp: uint256[N_COINS] = self._xp_mem(rates, new_balances) D2: uint256 = self.get_D(xp, amp) mint_amount = total_supply * (D2 - D0) / D0 self.save_p(xp, amp, D2) else: self.balances = new_balances mint_amount = D1 # Take the dust if there was any assert mint_amount >= _min_mint_amount, "Slippage screwed you" # Mint pool tokens total_supply += mint_amount self.balanceOf[_receiver] += mint_amount self.totalSupply = total_supply log Transfer(empty(address), _receiver, mint_amount) log AddLiquidity(msg.sender, _amounts, fees, D1, total_supply) return mint_amount @view @internal def get_y(i: int128, j: int128, x: uint256, xp: uint256[N_COINS], _amp: uint256, _D: uint256) -> uint256: """ Calculate x[j] if one makes x[i] = x Done by solving quadratic equation iteratively. x_1**2 + x_1 * (sum' - (A*n**n - 1) * D / (A * n**n)) = D ** (n + 1) / (n ** (2 * n) * prod' * A) x_1**2 + b*x_1 = c x_1 = (x_1**2 + c) / (2*x_1 + b) """ # x in the input is converted to the same price/precision assert i != j # dev: same coin assert j >= 0 # dev: j below zero assert j < N_COINS_128 # dev: j above N_COINS # should be unreachable, but good for safety assert i >= 0 assert i < N_COINS_128 amp: uint256 = _amp D: uint256 = _D if _D == 0: amp = self._A() D = self.get_D(xp, amp) S_: uint256 = 0 _x: uint256 = 0 y_prev: uint256 = 0 c: uint256 = D Ann: uint256 = amp * N_COINS for _i in range(N_COINS_128): if _i == i: _x = x elif _i != j: _x = xp[_i] else: continue S_ += _x c = c * D / (_x * N_COINS) c = c * D * A_PRECISION / (Ann * N_COINS) b: uint256 = S_ + D * A_PRECISION / Ann # - D y: uint256 = D for _i in range(255): y_prev = y y = (y*y + c) / (2 * y + b - D) # Equality with the precision of 1 if y > y_prev: if y - y_prev <= 1: return y else: if y_prev - y <= 1: return y raise @view @external def get_dy(i: int128, j: int128, dx: uint256) -> uint256: """ @notice Calculate the current output dy given input dx @dev Index values can be found via the `coins` public getter method @param i Index value for the coin to send @param j Index valie of the coin to recieve @param dx Amount of `i` being exchanged @return Amount of `j` predicted """ rates: uint256[N_COINS] = self.rate_multipliers xp: uint256[N_COINS] = self._xp_mem(rates, self.balances) x: uint256 = xp[i] + (dx * rates[i] / PRECISION) y: uint256 = self.get_y(i, j, x, xp, 0, 0) dy: uint256 = xp[j] - y - 1 fee: uint256 = self.fee * dy / FEE_DENOMINATOR return (dy - fee) * PRECISION / rates[j] @view @external def get_dx(i: int128, j: int128, dy: uint256) -> uint256: """ @notice Calculate the current input dx given output dy @dev Index values can be found via the `coins` public getter method @param i Index value for the coin to send @param j Index valie of the coin to recieve @param dy Amount of `j` being received after exchange @return Amount of `i` predicted """ rates: uint256[N_COINS] = self.rate_multipliers xp: uint256[N_COINS] = self._xp_mem(rates, self.balances) y: uint256 = xp[j] - (dy * rates[j] / PRECISION + 1) * FEE_DENOMINATOR / (FEE_DENOMINATOR - self.fee) x: uint256 = self.get_y(j, i, y, xp, 0, 0) return (x - xp[i]) * PRECISION / rates[i] @external @nonreentrant('lock') def exchange( i: int128, j: int128, _dx: uint256, _min_dy: uint256, _receiver: address = msg.sender, ) -> uint256: """ @notice Perform an exchange between two coins @dev Index values can be found via the `coins` public getter method @param i Index value for the coin to send @param j Index valie of the coin to recieve @param _dx Amount of `i` being exchanged @param _min_dy Minimum amount of `j` to receive @return Actual amount of `j` received """ rates: uint256[N_COINS] = self.rate_multipliers old_balances: uint256[N_COINS] = self.balances xp: uint256[N_COINS] = self._xp_mem(rates, old_balances) x: uint256 = xp[i] + _dx * rates[i] / PRECISION amp: uint256 = self._A() D: uint256 = self.get_D(xp, amp) y: uint256 = self.get_y(i, j, x, xp, amp, D) dy: uint256 = xp[j] - y - 1 # -1 just in case there were some rounding errors dy_fee: uint256 = dy * self.fee / FEE_DENOMINATOR # Convert all to real units dy = (dy - dy_fee) * PRECISION / rates[j] assert dy >= _min_dy, "Exchange resulted in fewer coins than expected" # xp is not used anymore, so we reuse it for price calc xp[i] = x xp[j] = y # D is not changed because we did not apply a fee self.save_p(xp, amp, D) dy_admin_fee: uint256 = dy_fee * ADMIN_FEE / FEE_DENOMINATOR dy_admin_fee = dy_admin_fee * PRECISION / rates[j] # Change balances exactly in same way as we change actual ERC20 coin amounts self.balances[i] = old_balances[i] + _dx # When rounding errors happen, we undercharge admin fee in favor of LP self.balances[j] = old_balances[j] - dy - dy_admin_fee assert ERC20(self.coins[i]).transferFrom(msg.sender, self, _dx, default_return_value=True) # dev: failed transfer assert ERC20(self.coins[j]).transfer(_receiver, dy, default_return_value=True) # dev: failed transfer log TokenExchange(msg.sender, i, _dx, j, dy) return dy @external @nonreentrant('lock') def remove_liquidity( _burn_amount: uint256, _min_amounts: uint256[N_COINS], _receiver: address = msg.sender ) -> uint256[N_COINS]: """ @notice Withdraw coins from the pool @dev Withdrawal amounts are based on current deposit ratios @param _burn_amount Quantity of LP tokens to burn in the withdrawal @param _min_amounts Minimum amounts of underlying coins to receive @param _receiver Address that receives the withdrawn coins @return List of amounts of coins that were withdrawn """ total_supply: uint256 = self.totalSupply amounts: uint256[N_COINS] = empty(uint256[N_COINS]) for i in range(N_COINS): old_balance: uint256 = self.balances[i] value: uint256 = old_balance * _burn_amount / total_supply assert value >= _min_amounts[i], "Withdrawal resulted in fewer coins than expected" self.balances[i] = old_balance - value amounts[i] = value assert ERC20(self.coins[i]).transfer(_receiver, value, default_return_value=True) # dev: failed transfer total_supply -= _burn_amount self.balanceOf[msg.sender] -= _burn_amount self.totalSupply = total_supply log Transfer(msg.sender, empty(address), _burn_amount) log RemoveLiquidity(msg.sender, amounts, empty(uint256[N_COINS]), total_supply) return amounts @external @nonreentrant('lock') def remove_liquidity_imbalance( _amounts: uint256[N_COINS], _max_burn_amount: uint256, _receiver: address = msg.sender ) -> uint256: """ @notice Withdraw coins from the pool in an imbalanced amount @param _amounts List of amounts of underlying coins to withdraw @param _max_burn_amount Maximum amount of LP token to burn in the withdrawal @param _receiver Address that receives the withdrawn coins @return Actual amount of the LP token burned in the withdrawal """ amp: uint256 = self._A() rates: uint256[N_COINS] = self.rate_multipliers old_balances: uint256[N_COINS] = self.balances D0: uint256 = self.get_D_mem(rates, old_balances, amp) new_balances: uint256[N_COINS] = old_balances for i in range(N_COINS): amount: uint256 = _amounts[i] if amount != 0: new_balances[i] -= amount assert ERC20(self.coins[i]).transfer(_receiver, amount, default_return_value=True) # dev: failed transfer D1: uint256 = self.get_D_mem(rates, new_balances, amp) fees: uint256[N_COINS] = empty(uint256[N_COINS]) base_fee: uint256 = self.fee * N_COINS / (4 * (N_COINS - 1)) for i in range(N_COINS): ideal_balance: uint256 = D1 * old_balances[i] / D0 difference: uint256 = 0 new_balance: uint256 = new_balances[i] if ideal_balance > new_balance: difference = ideal_balance - new_balance else: difference = new_balance - ideal_balance fees[i] = base_fee * difference / FEE_DENOMINATOR self.balances[i] = new_balance - (fees[i] * ADMIN_FEE / FEE_DENOMINATOR) new_balances[i] -= fees[i] new_balances = self._xp_mem(rates, new_balances) D2: uint256 = self.get_D(new_balances, amp) self.save_p(new_balances, amp, D2) total_supply: uint256 = self.totalSupply burn_amount: uint256 = ((D0 - D2) * total_supply / D0) + 1 assert burn_amount > 1 # dev: zero tokens burned assert burn_amount <= _max_burn_amount, "Slippage screwed you" total_supply -= burn_amount self.totalSupply = total_supply self.balanceOf[msg.sender] -= burn_amount log Transfer(msg.sender, empty(address), burn_amount) log RemoveLiquidityImbalance(msg.sender, _amounts, fees, D1, total_supply) return burn_amount @pure @internal def get_y_D(A: uint256, i: int128, xp: uint256[N_COINS], D: uint256) -> uint256: """ Calculate x[i] if one reduces D from being calculated for xp to D Done by solving quadratic equation iteratively. x_1**2 + x_1 * (sum' - (A*n**n - 1) * D / (A * n**n)) = D ** (n + 1) / (n ** (2 * n) * prod' * A) x_1**2 + b*x_1 = c x_1 = (x_1**2 + c) / (2*x_1 + b) """ # x in the input is converted to the same price/precision assert i >= 0 # dev: i below zero assert i < N_COINS_128 # dev: i above N_COINS S_: uint256 = 0 _x: uint256 = 0 y_prev: uint256 = 0 c: uint256 = D Ann: uint256 = A * N_COINS for _i in range(N_COINS_128): if _i != i: _x = xp[_i] else: continue S_ += _x c = c * D / (_x * N_COINS) c = c * D * A_PRECISION / (Ann * N_COINS) b: uint256 = S_ + D * A_PRECISION / Ann y: uint256 = D for _i in range(255): y_prev = y y = (y*y + c) / (2 * y + b - D) # Equality with the precision of 1 if y > y_prev: if y - y_prev <= 1: return y else: if y_prev - y <= 1: return y raise @view @internal def _calc_withdraw_one_coin(_burn_amount: uint256, i: int128) -> uint256[3]: # First, need to calculate # * Get current D # * Solve Eqn against y_i for D - _token_amount amp: uint256 = self._A() rates: uint256[N_COINS] = self.rate_multipliers xp: uint256[N_COINS] = self._xp_mem(rates, self.balances) D0: uint256 = self.get_D(xp, amp) total_supply: uint256 = self.totalSupply D1: uint256 = D0 - _burn_amount * D0 / total_supply new_y: uint256 = self.get_y_D(amp, i, xp, D1) base_fee: uint256 = self.fee * N_COINS / (4 * (N_COINS - 1)) xp_reduced: uint256[N_COINS] = empty(uint256[N_COINS]) for j in range(N_COINS_128): dx_expected: uint256 = 0 xp_j: uint256 = xp[j] if j == i: dx_expected = xp_j * D1 / D0 - new_y else: dx_expected = xp_j - xp_j * D1 / D0 xp_reduced[j] = xp_j - base_fee * dx_expected / FEE_DENOMINATOR dy: uint256 = xp_reduced[i] - self.get_y_D(amp, i, xp_reduced, D1) dy_0: uint256 = (xp[i] - new_y) * PRECISION / rates[i] # w/o fees dy = (dy - 1) * PRECISION / rates[i] # Withdraw less to account for rounding errors xp[i] = new_y last_p: uint256 = 0 if new_y > 0: last_p = self._get_p(xp, amp, D1) return [dy, dy_0 - dy, last_p] @view @external def calc_withdraw_one_coin(_burn_amount: uint256, i: int128) -> uint256: """ @notice Calculate the amount received when withdrawing a single coin @param _burn_amount Amount of LP tokens to burn in the withdrawal @param i Index value of the coin to withdraw @return Amount of coin received """ return self._calc_withdraw_one_coin(_burn_amount, i)[0] @external @nonreentrant('lock') def remove_liquidity_one_coin( _burn_amount: uint256, i: int128, _min_received: uint256, _receiver: address = msg.sender, ) -> uint256: """ @notice Withdraw a single coin from the pool @param _burn_amount Amount of LP tokens to burn in the withdrawal @param i Index value of the coin to withdraw @param _min_received Minimum amount of coin to receive @param _receiver Address that receives the withdrawn coins @return Amount of coin received """ dy: uint256[3] = self._calc_withdraw_one_coin(_burn_amount, i) assert dy[0] >= _min_received, "Not enough coins removed" self.balances[i] -= (dy[0] + dy[1] * ADMIN_FEE / FEE_DENOMINATOR) total_supply: uint256 = self.totalSupply - _burn_amount self.totalSupply = total_supply self.balanceOf[msg.sender] -= _burn_amount log Transfer(msg.sender, empty(address), _burn_amount) assert ERC20(self.coins[i]).transfer(_receiver, dy[0], default_return_value=True) # dev: failed transfer log RemoveLiquidityOne(msg.sender, _burn_amount, dy[0], total_supply) self.save_p_from_price(dy[2]) return dy[0] @external def ramp_A(_future_A: uint256, _future_time: uint256): assert msg.sender == Factory(self.factory).admin() # dev: only owner assert block.timestamp >= self.initial_A_time + MIN_RAMP_TIME assert _future_time >= block.timestamp + MIN_RAMP_TIME # dev: insufficient time _initial_A: uint256 = self._A() _future_A_p: uint256 = _future_A * A_PRECISION assert _future_A > 0 and _future_A < MAX_A if _future_A_p < _initial_A: assert _future_A_p * MAX_A_CHANGE >= _initial_A else: assert _future_A_p <= _initial_A * MAX_A_CHANGE self.initial_A = _initial_A self.future_A = _future_A_p self.initial_A_time = block.timestamp self.future_A_time = _future_time log RampA(_initial_A, _future_A_p, block.timestamp, _future_time) @external def stop_ramp_A(): assert msg.sender == Factory(self.factory).admin() # dev: only owner current_A: uint256 = self._A() self.initial_A = current_A self.future_A = current_A self.initial_A_time = block.timestamp self.future_A_time = block.timestamp # now (block.timestamp < t1) is always False, so we return saved A log StopRampA(current_A, block.timestamp) @external def set_ma_exp_time(_ma_exp_time: uint256): assert msg.sender == Factory(self.factory).admin() # dev: only owner assert _ma_exp_time != 0 self.ma_exp_time = _ma_exp_time @view @external def admin_balances(i: uint256) -> uint256: return ERC20(self.coins[i]).balanceOf(self) - self.balances[i] @external def commit_new_fee(_new_fee: uint256): assert msg.sender == Factory(self.factory).admin() assert _new_fee <= MAX_FEE assert self.admin_action_deadline == 0 self.future_fee = _new_fee self.admin_action_deadline = block.timestamp + ADMIN_ACTIONS_DEADLINE_DT log CommitNewFee(_new_fee) @external def apply_new_fee(): assert msg.sender == Factory(self.factory).admin() deadline: uint256 = self.admin_action_deadline assert deadline != 0 and block.timestamp >= deadline fee: uint256 = self.future_fee self.fee = fee self.admin_action_deadline = 0 log ApplyNewFee(fee) @external def withdraw_admin_fees(): receiver: address = Factory(self.factory).get_fee_receiver(self) for i in range(N_COINS): coin: address = self.coins[i] fees: uint256 = ERC20(coin).balanceOf(self) - self.balances[i] assert ERC20(coin).transfer(receiver, fees, default_return_value=True) @pure @external def version() -> String[8]: """ @notice Get the version of this token contract """ return VERSION
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A token is a representation of an on-chain or off-chain asset. The token page shows information such as price, total supply, holders, transfers and social links. Learn more about this page in our Knowledge Base.