文件 1 的 1：Vyper_contract.vy
# @version 0.2.8
"""
@title Curve IronBank Pool
@author Curve.Fi
@license Copyright (c) Curve.Fi, 2021 - all rights reserved
@notice Pool for swapping between cyTokens (cyDAI, cyUSDC, cyUSDT)
"""
# External Contracts
interface cyToken:
def transfer(_to: address, _value: uint256) -> bool: nonpayable
def transferFrom(_from: address, _to: address, _value: uint256) -> bool: nonpayable
def mint(mintAmount: uint256) -> uint256: nonpayable
def redeem(redeemTokens: uint256) -> uint256: nonpayable
def exchangeRateStored() -> uint256: view
def exchangeRateCurrent() -> uint256: nonpayable
def supplyRatePerBlock() -> uint256: view
def accrualBlockNumber() -> uint256: view
interface CurveToken:
def mint(_to: address, _value: uint256) -> bool: nonpayable
def burnFrom(_to: address, _value: uint256) -> bool: nonpayable
interface ERC20:
def transfer(_to: address, _value: uint256): nonpayable
def transferFrom(_from: address, _to: address, _value: uint256): nonpayable
def totalSupply() -> uint256: view
def balanceOf(_addr: address) -> uint256: view
# Events
event TokenExchange:
buyer: indexed(address)
sold_id: int128
tokens_sold: uint256
bought_id: int128
tokens_bought: uint256
event TokenExchangeUnderlying:
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
event RemoveLiquidityImbalance:
provider: indexed(address)
token_amounts: uint256[N_COINS]
fees: uint256[N_COINS]
invariant: uint256
token_supply: uint256
event CommitNewAdmin:
deadline: indexed(uint256)
admin: indexed(address)
event NewAdmin:
admin: indexed(address)
event CommitNewFee:
deadline: indexed(uint256)
fee: uint256
admin_fee: uint256
event NewFee:
fee: uint256
admin_fee: uint256
event RampA:
old_A: uint256
new_A: uint256
initial_time: uint256
future_time: uint256
event StopRampA:
A: uint256
t: uint256
# These constants must be set prior to compiling
N_COINS: constant(int128) = 3
PRECISION_MUL: constant(uint256[N_COINS]) = [1, 1000000000000, 1000000000000]
# fixed constants
FEE_DENOMINATOR: constant(uint256) = 10 ** 10
PRECISION: constant(uint256) = 10 ** 18 # The precision to convert to
MAX_ADMIN_FEE: constant(uint256) = 10 * 10 ** 9
MAX_FEE: constant(uint256) = 5 * 10 ** 9
MAX_A: constant(uint256) = 10 ** 6
MAX_A_CHANGE: constant(uint256) = 10
ADMIN_ACTIONS_DELAY: constant(uint256) = 3 * 86400
MIN_RAMP_TIME: constant(uint256) = 86400
coins: public(address[N_COINS])
underlying_coins: public(address[N_COINS])
balances: public(uint256[N_COINS])
previous_balances: public(uint256[N_COINS])
block_timestamp_last: public(uint256)
fee: public(uint256) # fee * 1e10
admin_fee: public(uint256) # admin_fee * 1e10
owner: public(address)
lp_token: public(address)
A_PRECISION: constant(uint256) = 100
initial_A: public(uint256)
future_A: public(uint256)
initial_A_time: public(uint256)
future_A_time: public(uint256)
admin_actions_deadline: public(uint256)
transfer_ownership_deadline: public(uint256)
future_fee: public(uint256)
future_admin_fee: public(uint256)
future_owner: public(address)
is_killed: bool
kill_deadline: uint256
KILL_DEADLINE_DT: constant(uint256) = 2 * 30 * 86400
@external
def __init__(
_owner: address,
_coins: address[N_COINS],
_underlying_coins: address[N_COINS],
_pool_token: address,
_A: uint256,
_fee: uint256,
_admin_fee: uint256,
):
"""
@notice Contract constructor
@param _owner Contract owner address
@param _coins Addresses of ERC20 contracts of wrapped coins
@param _underlying_coins Addresses of ERC20 contracts of underlying coins
@param _pool_token Address of the token representing LP share
@param _A Amplification coefficient multiplied by n * (n - 1)
@param _fee Fee to charge for exchanges
@param _admin_fee Admin fee
"""
for i in range(N_COINS):
assert _coins[i] != ZERO_ADDRESS
assert _underlying_coins[i] != ZERO_ADDRESS
# approve underlying coins for infinite transfers
_response: Bytes[32] = raw_call(
_underlying_coins[i],
concat(
method_id("approve(address,uint256)"),
convert(_coins[i], bytes32),
convert(MAX_UINT256, bytes32),
),
max_outsize=32,
)
if len(_response) > 0:
assert convert(_response, bool)
self.coins = _coins
self.underlying_coins = _underlying_coins
self.initial_A = _A * A_PRECISION
self.future_A = _A * A_PRECISION
self.fee = _fee
self.admin_fee = _admin_fee
self.owner = _owner
self.kill_deadline = block.timestamp + KILL_DEADLINE_DT
self.lp_token = _pool_token
@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 A() -> uint256:
return self._A() / A_PRECISION
@view
@external
def A_precise() -> uint256:
return self._A()
@view
@internal
def _stored_rates() -> uint256[N_COINS]:
# exchangeRateStored * (1 + supplyRatePerBlock * (getBlockNumber - accrualBlockNumber) / 1e18)
result: uint256[N_COINS] = PRECISION_MUL
for i in range(N_COINS):
coin: address = self.coins[i]
rate: uint256 = cyToken(coin).exchangeRateStored()
rate += rate * cyToken(coin).supplyRatePerBlock() * (block.number - cyToken(coin).accrualBlockNumber()) / PRECISION
result[i] *= rate
return result
@internal
def _update():
"""
Commits pre-change balances for the previous block
Can be used to compare against current values for flash loan checks
"""
if block.timestamp > self.block_timestamp_last:
self.previous_balances = self.balances
self.block_timestamp_last = block.timestamp
@internal
def _current_rates() -> uint256[N_COINS]:
self._update()
result: uint256[N_COINS] = PRECISION_MUL
for i in range(N_COINS):
result[i] *= cyToken(self.coins[i]).exchangeRateCurrent()
return result
@view
@internal
def _xp(rates: uint256[N_COINS]) -> uint256[N_COINS]:
result: uint256[N_COINS] = empty(uint256[N_COINS])
for i in range(N_COINS):
result[i] = rates[i] * self.balances[i] / PRECISION
return result
@pure
@internal
def get_D(xp: uint256[N_COINS], amp: uint256) -> uint256:
S: uint256 = 0
Dprev: 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
for _x in xp:
D_P = D_P * D / (_x * N_COINS) # If division by 0, this will be borked: only withdrawal will work. And that is good
Dprev = 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] = empty(uint256[N_COINS])
for i in range(N_COINS):
xp[i] = rates[i] * _balances[i] / PRECISION
return self.get_D(xp, _amp)
@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
"""
D: uint256 = self.get_D(self._xp(self._stored_rates()), self._A())
# 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 / ERC20(self.lp_token).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
@dev This calculation accounts for slippage, but not fees.
Needed to prevent front-running, not for precise calculations!
@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()
rates: uint256[N_COINS] = self._stored_rates()
_balances: uint256[N_COINS] = self.balances
D0: uint256 = self.get_D_mem(rates, _balances, amp)
for i in range(N_COINS):
_amount: uint256 = amounts[i]
if is_deposit:
_balances[i] += _amount
else:
_balances[i] -= _amount
D1: uint256 = self.get_D_mem(rates, _balances, amp)
token_amount: uint256 = ERC20(self.lp_token).totalSupply()
diff: uint256 = 0
if is_deposit:
diff = D1 - D0
else:
diff = D0 - D1
return diff * token_amount / D0
@external
@nonreentrant('lock')
def add_liquidity(
_amounts: uint256[N_COINS],
_min_mint_amount: uint256,
_use_underlying: bool = False
) -> 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 _use_underlying If True, deposit underlying assets instead of cyTokens
@return Amount of LP tokens received by depositing
"""
assert not self.is_killed
amp: uint256 = self._A()
rates: uint256[N_COINS] = self._current_rates()
_lp_token: address = self.lp_token
token_supply: uint256 = ERC20(_lp_token).totalSupply()
# Initial invariant
old_balances: uint256[N_COINS] = self.balances
D0: uint256 = self.get_D_mem(rates, old_balances, amp)
# Take coins from the sender
new_balances: uint256[N_COINS] = old_balances
amounts: uint256[N_COINS] = empty(uint256[N_COINS])
for i in range(N_COINS):
amount: uint256 = _amounts[i]
if amount == 0:
assert token_supply > 0
else:
coin: address = self.coins[i]
if _use_underlying:
ERC20(self.underlying_coins[i]).transferFrom(msg.sender, self, amount)
before: uint256 = ERC20(coin).balanceOf(self)
assert cyToken(coin).mint(amount) == 0
amount = ERC20(coin).balanceOf(self) - before
else:
assert cyToken(coin).transferFrom(msg.sender, self, amount)
amounts[i] = amount
new_balances[i] += amount
# 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 token_supply != 0:
# Only account for fees if we are not the first to deposit
_fee: uint256 = self.fee * N_COINS / (4 * (N_COINS - 1))
_admin_fee: uint256 = self.admin_fee
difference: uint256 = 0
for i in range(N_COINS):
new_balance: uint256 = new_balances[i]
ideal_balance: uint256 = D1 * old_balances[i] / D0
if ideal_balance > new_balance:
difference = ideal_balance - new_balance
else:
difference = new_balance - ideal_balance
fees[i] = _fee * difference / FEE_DENOMINATOR
self.balances[i] = new_balance - (fees[i] * _admin_fee / FEE_DENOMINATOR)
new_balances[i] -= fees[i]
D2: uint256 = self.get_D_mem(rates, new_balances, amp)
mint_amount = token_supply * (D2 - D0) / D0
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
CurveToken(_lp_token).mint(msg.sender, mint_amount)
log AddLiquidity(msg.sender, amounts, fees, D1, token_supply + mint_amount)
return mint_amount
@view
@internal
def get_y(i: int128, j: int128, x: uint256, xp_: uint256[N_COINS]) -> uint256:
# 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 # dev: j above N_COINS
# should be unreachable, but good for safety
assert i >= 0
assert i < N_COINS
A_: uint256 = self._A()
D: uint256 = self.get_D(xp_, A_)
Ann: uint256 = A_ * N_COINS
c: uint256 = D
S_: uint256 = 0
_x: uint256 = 0
y_prev: uint256 = 0
for _i in range(N_COINS):
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:
# dx and dy in c-units
rates: uint256[N_COINS] = self._stored_rates()
xp: uint256[N_COINS] = self._xp(rates)
x: uint256 = xp[i] + dx * rates[i] / PRECISION
y: uint256 = self.get_y(i, j, x, xp)
dy: uint256 = xp[j] - y - 1
return (dy - (self.fee * dy / FEE_DENOMINATOR)) * PRECISION / rates[j]
@view
@external
def get_dx(i: int128, j: int128, dy: uint256) -> uint256:
# dx and dy in c-units
rates: uint256[N_COINS] = self._stored_rates()
xp: uint256[N_COINS] = self._xp(rates)
y: uint256 = xp[j] - (dy * FEE_DENOMINATOR / (FEE_DENOMINATOR - self.fee)) * rates[j] / PRECISION
x: uint256 = self.get_y(j, i, y, xp)
return (x - xp[i]) * PRECISION / rates[i]
@view
@external
def get_dy_underlying(i: int128, j: int128, dx: uint256) -> uint256:
# dx and dy in underlying units
rates: uint256[N_COINS] = self._stored_rates()
xp: uint256[N_COINS] = self._xp(rates)
precisions: uint256[N_COINS] = PRECISION_MUL
x: uint256 = xp[i] + dx * precisions[i]
dy: uint256 = xp[j] - self.get_y(i, j, x, xp) - 1
_fee: uint256 = self.fee * dy / FEE_DENOMINATOR
return (dy - _fee) / precisions[j]
@external
@view
def get_dx_underlying(i: int128, j: int128, dy: uint256) -> uint256:
# dx and dy in underlying units
rates: uint256[N_COINS] = self._stored_rates()
xp: uint256[N_COINS] = self._xp(rates)
precisions: uint256[N_COINS] = PRECISION_MUL
y: uint256 = xp[j] - (dy * FEE_DENOMINATOR / (FEE_DENOMINATOR - self.fee)) * precisions[j]
return (self.get_y(j, i, y, xp) - xp[i]) / precisions[i]
@internal
def _exchange(i: int128, j: int128, dx: uint256) -> uint256:
assert not self.is_killed
# dx and dy are in cy tokens
rates: uint256[N_COINS] = self._current_rates()
old_balances: uint256[N_COINS] = self.balances
xp: uint256[N_COINS] = empty(uint256[N_COINS])
for k in range(N_COINS):
xp[k] = rates[k] * old_balances[k] / PRECISION
x: uint256 = xp[i] + dx * rates[i] / PRECISION
dy: uint256 = xp[j] - self.get_y(i, j, x, xp) - 1 # -1 just in case there were some rounding errors
dy_fee: uint256 = dy * self.fee / FEE_DENOMINATOR
dy = (dy - dy_fee) * PRECISION / rates[j]
dy_admin_fee: uint256 = dy_fee * self.admin_fee / FEE_DENOMINATOR
dy_admin_fee = dy_admin_fee * PRECISION / rates[j]
self.balances[i] = old_balances[i] + dx
self.balances[j] = old_balances[j] - dy - dy_admin_fee
return dy
@external
@nonreentrant('lock')
def exchange(i: int128, j: int128, dx: uint256, min_dy: uint256) -> 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
"""
dy: uint256 = self._exchange(i, j, dx)
assert dy >= min_dy, "Too few coins in result"
assert cyToken(self.coins[i]).transferFrom(msg.sender, self, dx)
assert cyToken(self.coins[j]).transfer(msg.sender, dy)
log TokenExchange(msg.sender, i, dx, j, dy)
return dy
@external
@nonreentrant('lock')
def exchange_underlying(i: int128, j: int128, dx: uint256, min_dy: uint256) -> uint256:
"""
@notice Perform an exchange between two underlying coins
@dev Index values can be found via the `underlying_coins` public getter method
@param i Index value for the underlying coin to send
@param j Index valie of the underlying 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
"""
ERC20(self.underlying_coins[i]).transferFrom(msg.sender, self, dx)
coin: address = self.coins[i]
dx_: uint256 = ERC20(coin).balanceOf(self)
assert cyToken(coin).mint(dx) == 0
dx_ = ERC20(coin).balanceOf(self) - dx_
dy_: uint256 = self._exchange(i, j, dx_)
assert cyToken(self.coins[j]).redeem(dy_) == 0
underlying: address = self.underlying_coins[j]
dy: uint256 = ERC20(underlying).balanceOf(self)
assert dy >= min_dy, "Too few coins in result"
ERC20(underlying).transfer(msg.sender, dy)
log TokenExchangeUnderlying(msg.sender, i, dx, j, dy)
return dy
@external
@nonreentrant('lock')
def remove_liquidity(
_amount: uint256,
_min_amounts: uint256[N_COINS],
_use_underlying: bool = False
) -> uint256[N_COINS]:
"""
@notice Withdraw coins from the pool
@dev Withdrawal amounts are based on current deposit ratios
@param _amount Quantity of LP tokens to burn in the withdrawal
@param _min_amounts Minimum amounts of underlying coins to receive
@param _use_underlying If True, withdraw underlying assets instead of cyTokens
@return List of amounts of coins that were withdrawn
"""
self._update()
_lp_token: address = self.lp_token
total_supply: uint256 = ERC20(_lp_token).totalSupply()
amounts: uint256[N_COINS] = empty(uint256[N_COINS])
for i in range(N_COINS):
_balance: uint256 = self.balances[i]
value: uint256 = _balance * _amount / total_supply
self.balances[i] = _balance - value
amounts[i] = value
coin: address = self.coins[i]
if _use_underlying:
assert cyToken(coin).redeem(value) == 0
underlying: address = self.underlying_coins[i]
value = ERC20(underlying).balanceOf(self)
ERC20(underlying).transfer(msg.sender, value)
else:
assert cyToken(coin).transfer(msg.sender, value)
assert value >= _min_amounts[i]
CurveToken(_lp_token).burnFrom(msg.sender, _amount) # Will raise if not enough
log RemoveLiquidity(msg.sender, amounts, empty(uint256[N_COINS]), total_supply - _amount)
return amounts
@external
@nonreentrant('lock')
def remove_liquidity_imbalance(
_amounts: uint256[N_COINS],
_max_burn_amount: uint256,
_use_underlying: bool = False
) -> 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 _use_underlying If True, withdraw underlying assets instead of cyTokens
@return Actual amount of the LP token burned in the withdrawal
"""
assert not self.is_killed
amp: uint256 = self._A()
rates: uint256[N_COINS] = self._current_rates()
old_balances: uint256[N_COINS] = self.balances
D0: uint256 = self.get_D_mem(rates, old_balances, amp)
new_balances: uint256[N_COINS] = old_balances
amounts: uint256[N_COINS] = _amounts
precisions: uint256[N_COINS] = PRECISION_MUL
for i in range(N_COINS):
amount: uint256 = amounts[i]
if amount > 0:
if _use_underlying:
amount = amount * precisions[i] * PRECISION / rates[i]
amounts[i] = amount
new_balances[i] -= amount
D1: uint256 = self.get_D_mem(rates, new_balances, amp)
fees: uint256[N_COINS] = empty(uint256[N_COINS])
_fee: uint256 = self.fee * N_COINS / (4 * (N_COINS - 1))
_admin_fee: uint256 = self.admin_fee
for i in range(N_COINS):
ideal_balance: uint256 = D1 * old_balances[i] / D0
new_balance: uint256 = new_balances[i]
difference: uint256 = 0
if ideal_balance > new_balance:
difference = ideal_balance - new_balance
else:
difference = new_balance - ideal_balance
coin_fee: uint256 = _fee * difference / FEE_DENOMINATOR
self.balances[i] = new_balance - (coin_fee * _admin_fee / FEE_DENOMINATOR)
new_balances[i] -= coin_fee
fees[i] = coin_fee
D2: uint256 = self.get_D_mem(rates, new_balances, amp)
lp_token: address = self.lp_token
token_supply: uint256 = ERC20(lp_token).totalSupply()
token_amount: uint256 = (D0 - D2) * token_supply / D0
assert token_amount != 0
assert token_amount <= _max_burn_amount, "Slippage screwed you"
CurveToken(lp_token).burnFrom(msg.sender, token_amount) # dev: insufficient funds
for i in range(N_COINS):
amount: uint256 = amounts[i]
if amount != 0:
coin: address = self.coins[i]
if _use_underlying:
assert cyToken(coin).redeem(amount) == 0
underlying: address = self.underlying_coins[i]
ERC20(underlying).transfer(msg.sender, ERC20(underlying).balanceOf(self))
else:
assert cyToken(coin).transfer(msg.sender, amount)
log RemoveLiquidityImbalance(msg.sender, amounts, fees, D1, token_supply - token_amount)
return token_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 + x1 * (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 # dev: i above N_COINS
Ann: uint256 = A_ * N_COINS
c: uint256 = D
S_: uint256 = 0
_x: uint256 = 0
y_prev: uint256 = 0
for _i in range(N_COINS):
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(_token_amount: uint256, i: int128, _use_underlying: bool, _rates: uint256[N_COINS]) -> uint256[2]:
# First, need to calculate
# * Get current D
# * Solve Eqn against y_i for D - _token_amount
amp: uint256 = self._A()
xp: uint256[N_COINS] = self._xp(_rates)
D0: uint256 = self.get_D(xp, amp)
total_supply: uint256 = ERC20(self.lp_token).totalSupply()
D1: uint256 = D0 - _token_amount * D0 / total_supply
new_y: uint256 = self.get_y_D(amp, i, xp, D1)
xp_reduced: uint256[N_COINS] = xp
_fee: uint256 = self.fee * N_COINS / (4 * (N_COINS - 1))
rate: uint256 = _rates[i]
for j in range(N_COINS):
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] -= _fee * dx_expected / FEE_DENOMINATOR
dy: uint256 = xp_reduced[i] - self.get_y_D(amp, i, xp_reduced, D1)
dy = (dy - 1) * PRECISION / rate # Withdraw less to account for rounding errors
dy_fee: uint256 = ((xp[i] - new_y) * PRECISION / rate) - dy
if _use_underlying:
# this branch is only reachable when called via `calc_withdraw_one_coin`, which
# only needs `dy` - so we don't bother converting `dy_fee` to the underlying
precisions: uint256[N_COINS] = PRECISION_MUL
dy = dy * rate / precisions[i] / PRECISION
return [dy, dy_fee]
@view
@external
def calc_withdraw_one_coin(_token_amount: uint256, i: int128, _use_underlying: bool = False) -> uint256:
"""
@notice Calculate the amount received when withdrawing a single coin
@param _token_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(_token_amount, i, _use_underlying, self._stored_rates())[0]
@external
@nonreentrant('lock')
def remove_liquidity_one_coin(
_token_amount: uint256,
i: int128,
_min_amount: uint256,
_use_underlying: bool = False
) -> uint256:
"""
@notice Withdraw a single coin from the pool
@param _token_amount Amount of LP tokens to burn in the withdrawal
@param i Index value of the coin to withdraw
@param _min_amount Minimum amount of coin to receive
@param _use_underlying If True, withdraw underlying assets instead of cyTokens
@return Amount of coin received
"""
assert not self.is_killed # dev: is killed
dy: uint256[2] = self._calc_withdraw_one_coin(_token_amount, i, False, self._current_rates())
amount: uint256 = dy[0]
self.balances[i] -= (dy[0] + dy[1] * self.admin_fee / FEE_DENOMINATOR)
CurveToken(self.lp_token).burnFrom(msg.sender, _token_amount) # dev: insufficient funds
coin: address = self.coins[i]
if _use_underlying:
assert cyToken(coin).redeem(dy[0]) == 0
underlying: address = self.underlying_coins[i]
amount = ERC20(underlying).balanceOf(self)
ERC20(underlying).transfer(msg.sender, amount)
else:
assert cyToken(coin).transfer(msg.sender, amount)
assert amount >= _min_amount, "Not enough coins removed"
log RemoveLiquidityOne(msg.sender, _token_amount, dy[0])
return dy[0]
### Admin functions ###
@external
def ramp_A(_future_A: uint256, _future_time: uint256):
assert msg.sender == self.owner # 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 == self.owner # 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 commit_new_fee(new_fee: uint256, new_admin_fee: uint256):
assert msg.sender == self.owner # dev: only owner
assert self.admin_actions_deadline == 0 # dev: active action
assert new_fee <= MAX_FEE # dev: fee exceeds maximum
assert new_admin_fee <= MAX_ADMIN_FEE # dev: admin fee exceeds maximum
_deadline: uint256 = block.timestamp + ADMIN_ACTIONS_DELAY
self.admin_actions_deadline = _deadline
self.future_fee = new_fee
self.future_admin_fee = new_admin_fee
log CommitNewFee(_deadline, new_fee, new_admin_fee)
@external
def apply_new_fee():
assert msg.sender == self.owner # dev: only owner
assert block.timestamp >= self.admin_actions_deadline # dev: insufficient time
assert self.admin_actions_deadline != 0 # dev: no active action
self.admin_actions_deadline = 0
_fee: uint256 = self.future_fee
_admin_fee: uint256 = self.future_admin_fee
self.fee = _fee
self.admin_fee = _admin_fee
log NewFee(_fee, _admin_fee)
@external
def revert_new_parameters():
assert msg.sender == self.owner # dev: only owner
self.admin_actions_deadline = 0
@external
def commit_transfer_ownership(_owner: address):
assert msg.sender == self.owner # dev: only owner
assert self.transfer_ownership_deadline == 0 # dev: active transfer
_deadline: uint256 = block.timestamp + ADMIN_ACTIONS_DELAY
self.transfer_ownership_deadline = _deadline
self.future_owner = _owner
log CommitNewAdmin(_deadline, _owner)
@external
def apply_transfer_ownership():
assert msg.sender == self.owner # dev: only owner
assert block.timestamp >= self.transfer_ownership_deadline # dev: insufficient time
assert self.transfer_ownership_deadline != 0 # dev: no active transfer
self.transfer_ownership_deadline = 0
_owner: address = self.future_owner
self.owner = _owner
log NewAdmin(_owner)
@external
def revert_transfer_ownership():
assert msg.sender == self.owner # dev: only owner
self.transfer_ownership_deadline = 0
@view
@external
def admin_balances(i: uint256) -> uint256:
return ERC20(self.coins[i]).balanceOf(self) - self.balances[i]
@external
def withdraw_admin_fees():
assert msg.sender == self.owner # dev: only owner
for i in range(N_COINS):
coin: address = self.coins[i]
value: uint256 = ERC20(coin).balanceOf(self) - self.balances[i]
if value > 0:
assert cyToken(coin).transfer(msg.sender, value)
@external
def kill_me():
assert msg.sender == self.owner # dev: only owner
assert self.kill_deadline > block.timestamp # dev: deadline has passed
self.is_killed = True
@external
def unkill_me():
assert msg.sender == self.owner # dev: only owner
self.is_killed = False
