Contract Name:
Vyper_contract
Contract Source Code:
File 1 of 1 : Vyper_contract
# Created by interfinex.io
# - The Greeks
from vyper.interfaces import ERC20
event Transfer:
sender: indexed(address)
receiver: indexed(address)
value: uint256
event Approval:
owner: indexed(address)
spender: indexed(address)
value: uint256
event ClaimDividends:
to: indexed(address)
value: uint256
totalDividends: uint256
event DistributeDividends:
sender: indexed(address)
value: uint256
totalDividends: uint256
name: public(String[64])
symbol: public(String[32])
decimals: public(uint256)
totalDividends: public(uint256)
totalClaimedTokenDividends: public(uint256)
totalTokenDividends: public(uint256)
dividend_token: public(address)
withdraw_address: public(address)
balanceOf: public(HashMap[address, uint256])
allowances: HashMap[address, HashMap[address, uint256]]
total_supply: public(uint256)
minter: public(address)
mintable: public(bool)
POINT_MULTIPLIER: constant(uint256) = 10 ** 24
lastDividends: public(HashMap[address, uint256])
@external
def initializeERC20(
_name: String[64],
_symbol: String[32],
_decimals: uint256,
_supply: uint256,
_dividend_token: address,
_mintable: bool
):
assert self.minter == ZERO_ADDRESS, "Cannot initialize contract more than once"
init_supply: uint256 = _supply * 10 ** _decimals
self.name = _name
self.symbol = _symbol
self.decimals = _decimals
self.balanceOf[msg.sender] = init_supply
self.total_supply = init_supply
self.minter = msg.sender
self.mintable = _mintable
self.dividend_token = _dividend_token
ERC20(self.dividend_token).approve(self, MAX_UINT256)
log Transfer(ZERO_ADDRESS, msg.sender, init_supply)
@view
@external
def totalSupply() -> uint256:
"""
@dev Total number of tokens in existence.
"""
return self.total_supply
@view
@external
def allowance(_owner : address, _spender : address) -> uint256:
"""
@dev Function to check the amount of tokens that an owner allowed to a spender.
@param _owner The address which owns the funds.
@param _spender The address which will spend the funds.
@return An uint256 specifying the amount of tokens still available for the spender.
"""
return self.allowances[_owner][_spender]
@view
@internal
def _dividendsOf(_owner: address) -> uint256:
return (self.totalDividends - self.lastDividends[_owner]) * self.balanceOf[_owner] / POINT_MULTIPLIER
@internal
def _distributeDividends(_from: address, _value: uint256):
if _value == 0:
return
ERC20(self.dividend_token).transferFrom(_from, self, _value)
# Ignore whatever the contract balance is because the contract can't claim dividends
self.totalDividends += _value * POINT_MULTIPLIER / (self.total_supply - self.balanceOf[self])
self.totalTokenDividends += _value
log DistributeDividends(_from, _value, self.totalDividends)
@external
def distributeDividends(_value: uint256):
self._distributeDividends(msg.sender, _value)
@internal
def _distributeExcessBalance():
"""
@dev Withdraw excess tokens in the contract. It's possible that excess tokens,
via dividends or some other means, will accrue in the contract. This provides
an escape hatch for those funds.
"""
excess_balance: uint256 = ERC20(self.dividend_token).balanceOf(self) - (self.totalTokenDividends - self.totalClaimedTokenDividends)
self._distributeDividends(self, excess_balance)
@external
def distributeExcessBalance():
self._distributeExcessBalance()
@view
@external
def getExcessBalance() -> uint256:
return ERC20(self.dividend_token).balanceOf(self) - (self.totalTokenDividends - self.totalClaimedTokenDividends)
@view
@external
def dividendsOf(_owner: address) -> uint256:
return self._dividendsOf(_owner)
@internal
def _claimDividends(_to: address):
if _to == self:
return
dividends: uint256 = self._dividendsOf(_to)
self.lastDividends[_to] = self.totalDividends
if dividends != 0:
ERC20(self.dividend_token).transfer(_to, dividends)
self.totalClaimedTokenDividends += dividends
log ClaimDividends(_to, dividends, self.totalDividends)
@external
def claimDividends():
self._claimDividends(msg.sender)
@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._claimDividends(msg.sender)
self._claimDividends(_to)
self.balanceOf[msg.sender] -= _value
self.balanceOf[_to] += _value
log 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._claimDividends(_from)
self._claimDividends(_to)
self.balanceOf[_from] -= _value
self.balanceOf[_to] += _value
self.allowances[_from][msg.sender] -= _value
log Transfer(_from, _to, _value)
return True
@external
def approve(_spender : address, _value : uint256) -> bool:
"""
@dev Approve the passed address to spend the specified amount of tokens on behalf of msg.sender.
Beware that changing an allowance with this method brings the risk that someone may use both the old
and the new allowance by unfortunate transaction ordering. One possible solution to mitigate this
race condition is to first reduce the spender's allowance to 0 and set the desired value afterwards:
https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
@param _spender The address which will spend the funds.
@param _value The amount of tokens to be spent.
"""
self.allowances[msg.sender][_spender] = _value
log Approval(msg.sender, _spender, _value)
return True
@external
def mint(_to: address, _value: uint256):
"""
@dev Mint an amount of the token and assigns it to an account.
This encapsulates the modification of balances such that the
proper events are emitted.
@param _to The account that will receive the created tokens.
@param _value The amount that will be created.
"""
assert self.mintable == True
assert msg.sender == self.minter
assert _to != ZERO_ADDRESS
self._claimDividends(_to)
self.total_supply += _value
self.balanceOf[_to] += _value
log Transfer(ZERO_ADDRESS, _to, _value)
@internal
def _burn(_to: address, _value: uint256):
"""
@dev Internal function that burns an amount of the token of a given
account.
@param _to The account whose tokens will be burned.
@param _value The amount that will be burned.
"""
assert _to != ZERO_ADDRESS
self._claimDividends(_to)
self.total_supply -= _value
self.balanceOf[_to] -= _value
log Transfer(_to, ZERO_ADDRESS, _value)
@external
def burn(_value: uint256):
"""
@dev Burn an amount of the token of msg.sender.
@param _value The amount that will be burned.
"""
self._claimDividends(msg.sender)
self._burn(msg.sender, _value)
@external
def burnFrom(_to: address, _value: uint256):
"""
@dev Burn an amount of the token from a given account.
@param _to The account whose tokens will be burned.
@param _value The amount that will be burned.
"""
self._claimDividends(msg.sender)
self.allowances[_to][msg.sender] -= _value
self._burn(_to, _value)