Contract Name:
TokenTimelock
Contract Source Code:
// SPDX-License-Identifier: MIT
pragma solidity ^0.6.0;
pragma experimental ABIEncoderV2;
import "./math/BigDiv.sol";
import "./math/Sqrt.sol";
import "./Take.sol";
import "./uniswap/IUniswapV2Router02.sol";
import "./uniswap/IUniswapV2Factory.sol";
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/token/ERC20/SafeERC20.sol";
import "@openzeppelin/contracts/math/SafeMath.sol";
import "@openzeppelin/contracts/utils/Address.sol";
import "@openzeppelin/contracts/token/ERC20/TokenTimelock.sol";
/**
* @title Decentralized Autonomous Trust
* This contract is a modified version of the implementation provided by Fairmint for a
* Decentralized Autonomous Trust as described in the continuous
* organization whitepaper (https://github.com/c-org/whitepaper) and
* specified here: https://github.com/fairmint/c-org/wiki.
* Code from : https://github.com/Fairmint/c-org/blob/dfd3129f9bce8717406aba54d1f1888d8e253dbb/contracts/DecentralizedAutonomousTrust.sol
* Changes Added: https://github.com/Fairmint/c-org/commit/60bb63b9112a82996f275a75a87c28b1d73e3f11
*
* Use at your own risk.
*/
contract DecentralizedAutonomousTrust
is Take
{
using SafeMath for uint;
using Sqrt for uint;
using SafeERC20 for IERC20;
/**
* Events
*/
event Buy(
address indexed _from,
address indexed _to,
uint256 _currencyValue,
uint256 _fairValue
);
event Close();
event StateChange(
uint256 _previousState,
uint256 _newState
);
event UpdateConfig(
address indexed _beneficiary,
address indexed _control,
address _uniswapRouterAddress,
address _uniswapFactoryAddress,
uint256 _minInvestment,
uint256 _openUntilAtLeast
);
// Constants
// The default state
uint256 private constant STATE_INIT = 0;
// The state after initGoal has been reached
uint256 private constant STATE_RUN = 1;
// The state after closed by the `beneficiary` account from STATE_RUN
uint256 private constant STATE_CLOSE = 2;
// The state after closed by the `beneficiary` account from STATE_INIT
uint256 private constant STATE_CANCEL = 3;
// When multiplying 2 terms, the max value is 2^128-1
uint256 private constant MAX_BEFORE_SQUARE = 2**128 - 1;
// The denominator component for values specified in basis points.
uint256 private constant BASIS_POINTS_DEN = 10000;
// The max `totalSupply`
// @dev This limit ensures that the DAT's formulas do not overflow (<MAX_BEFORE_SQUARE/2)
uint256 private constant MAX_SUPPLY = 10 ** 38;
/**
* Data for DAT business logic
*/
/// @notice The address of the beneficiary organization which receives the investments.
/// Points to the wallet of the organization.
address payable public beneficiary;
/// @notice The buy slope of the bonding curve.
/// Does not affect the financial model, only the granularity of TAKE.
/// @dev This is the numerator component of the fractional value.
uint256 public buySlopeNum;
/// @notice The buy slope of the bonding curve.
/// Does not affect the financial model, only the granularity of TAKE.
/// @dev This is the denominator component of the fractional value.
uint256 public buySlopeDen;
/// @notice The address from which the updatable variables can be updated
address public control;
/// @notice The address of the token used as reserve in the bonding curve
/// (e.g. the DAI contract). Use ETH if 0.
IERC20 public currency;
/// @notice The initial fundraising goal (expressed in TAKE) to start the c-org.
/// `0` means that there is no initial fundraising and the c-org immediately moves to run state.
uint256 public initGoal;
uint256 public initReserve;
/// @notice The bonding curve fundraising goal.
uint256 public bcGoal;
/// @notice The bonding curve fundraising final result.
uint256 public bcTakeReleased;
/// @notice The investment reserve of the c-org. Defines the percentage of the value invested that is
/// automatically funneled and held into the buyback_reserve expressed in basis points.
uint256 public investmentReserveBasisPoints;
/// @notice The earliest date/time (in seconds) that the DAT may enter the `CLOSE` state, ensuring
/// that if the DAT reaches the `RUN` state it will remain running for at least this period of time.
/// @dev This value may be increased anytime by the control account
uint256 public openUntilAtLeast;
/// @notice The minimum amount of `currency` investment accepted.
uint256 public minInvestment;
/// @notice The current state of the contract.
/// @dev See the constants above for possible state values.
uint256 public state;
string public constant version = "2";
// --- EIP712 niceties ---
// Original source: https://etherscan.io/address/0x6b175474e89094c44da98b954eedeac495271d0f#code
// mapping (address => uint) public nonces;
bytes32 public DOMAIN_SEPARATOR;
// bytes32 public constant PERMIT_TYPEHASH = keccak256("Permit(address holder,address spender,uint256 nonce,uint256 expiry,bool allowed)");
bytes32 public constant PERMIT_TYPEHASH = 0xea2aa0a1be11a07ed86d755c93467f4f82362b452371d1ba94d1715123511acb;
address public uniswapFactoryAddress;
address public uniswapRouterAddress;
IUniswapV2Router02 private uniswapRouter;
IUniswapV2Factory private uniswapFactory;
address internal constant NULL_ADDRESS = 0x0000000000000000000000000000000000000000;
uint96 private constant uniswapBurnRate = 1000;
address public uniswapPairAddress = 0x0000000000000000000000000000000000000000;
address public uniswapTokenTimelockAddress = 0x0000000000000000000000000000000000000000;
address public takeTimelockAddress = 0x0000000000000000000000000000000000000000;
// Team Revenue in percent
uint256 private constant teamRevenueBasisPoints = 3000;
//
bool public bcFlowAllowed = false;
/// Pay
/// @notice Pay the organization on-chain without minting any tokens.
/// @dev This allows you to add funds directly to the buybackReserve.
function pay() external payable
{
require(address(currency) == address(0), "ONLY_FOR_CURRENCY_ETH");
}
function handleBC(
bool withdrawOnError
) external
{
require(state == STATE_CLOSE, "ONLY_AFTER_CLOSE");
require(msg.sender == beneficiary, "BENEFICIARY_ONLY");
uint256 reserve = address(this).balance;
require(reserve > 0, "MUST_BUY_AT_LEAST_1");
uint256 teamReserve = reserve.mul(teamRevenueBasisPoints);
teamReserve /= BASIS_POINTS_DEN;
uint256 uniswapPoolEthAmount = reserve.sub(teamReserve);
uint256 uniswapPoolTakeAmount = uniswapPoolEthAmount.mul(buySlopeDen);
uniswapPoolTakeAmount = uniswapPoolTakeAmount.div(bcTakeReleased);
uniswapPoolTakeAmount = uniswapPoolTakeAmount.div(buySlopeNum);
super._allowTokenTransfer();
super._approve(address(this), uniswapRouterAddress, uint(-1));
try uniswapRouter.addLiquidityETH{
value: uniswapPoolEthAmount
}(
address(this),
uniswapPoolTakeAmount,
uniswapPoolTakeAmount,
uniswapPoolEthAmount,
address(this),
block.timestamp + 15
) returns (uint256 amountToken, uint256 amountETH, uint256 liquidity) {
Address.sendValue(beneficiary, address(this).balance);
uniswapPairAddress = uniswapFactory.getPair(uniswapRouter.WETH(), address(this));
super._setBurnConfig(uniswapBurnRate, NULL_ADDRESS);
super._addBurnSaleAddress(uniswapPairAddress);
super._setApproveConfig(NULL_ADDRESS);
lockTakeTokens();
} catch {
if (withdrawOnError) {
Address.sendValue(beneficiary, address(this).balance);
uint96 amount = safe96(this.balanceOf(address(this)), "DAT:: amount exceeds 96 bits");
super._transferTokens(address(this), beneficiary, amount);
}
}
}
function lockUniswapTokens() external {
require(state == STATE_CLOSE, "ONLY_AFTER_CLOSE");
require(msg.sender == beneficiary, "BENEFICIARY_ONLY");
IERC20 uniswapPair = IERC20(uniswapPairAddress);
TokenTimelock uniswapTokenTimelock = new TokenTimelock(uniswapPair, beneficiary, block.timestamp + 31 days);
uniswapTokenTimelockAddress = address(uniswapTokenTimelock);
uniswapPair.transfer(uniswapTokenTimelockAddress, uniswapPair.balanceOf(address(this)) );
}
// --- Approve by signature ---
// Original source: https://etherscan.io/address/0x6b175474e89094c44da98b954eedeac495271d0f#code
function permit(
address holder,
address spender,
uint256 nonce,
uint256 expiry,
bool allowed,
uint8 v,
bytes32 r,
bytes32 s
) external
{
bytes32 digest = keccak256(
abi.encodePacked(
"\x19\x01",
DOMAIN_SEPARATOR,
keccak256(
abi.encode(PERMIT_TYPEHASH,
holder,
spender,
nonce,
expiry,
allowed
)
)
)
);
require(holder != address(0), "DAT/invalid-address-0");
require(holder == ecrecover(digest, v, r, s), "DAT/invalid-permit");
require(expiry == 0 || now <= expiry, "DAT/permit-expired");
require(nonce == nonces[holder]++, "DAT/invalid-nonce");
uint256 wad = allowed ? uint(-1) : 0;
super._approve(holder, spender, wad);
}
/**
* Config / Control
*/
/// @notice Called once after deploy to set the initial configuration.
/// None of the values provided here may change once initially set.
/// @dev using the init pattern in order to support zos upgrades
function initialize(
address _currencyAddress,
uint256 _initGoal,
uint256 _bcGoal,
uint256 _buySlopeNum,
uint256 _buySlopeDen,
uint256 _investmentReserveBasisPoints
) public
{
require(control == address(0), "ALREADY_INITIALIZED");
initReserve = 0;
// Set initGoal, which in turn defines the initial state
if(_initGoal == 0)
{
emit StateChange(state, STATE_RUN);
state = STATE_RUN;
}
else
{
// Math: If this value got too large, the DAT would overflow on sell
require(_initGoal < MAX_SUPPLY, "EXCESSIVE_GOAL");
initGoal = _initGoal;
}
require(_bcGoal > 0, "INVALID_BC_GOAL");
bcGoal = _bcGoal;
bcTakeReleased = 0;
require(_buySlopeNum > 0, "INVALID_SLOPE_NUM");
require(_buySlopeDen > 0, "INVALID_SLOPE_DEN");
require(_buySlopeNum < MAX_BEFORE_SQUARE, "EXCESSIVE_SLOPE_NUM");
require(_buySlopeDen < MAX_BEFORE_SQUARE, "EXCESSIVE_SLOPE_DEN");
buySlopeNum = _buySlopeNum;
buySlopeDen = _buySlopeDen;
// 100% or less
require(_investmentReserveBasisPoints <= BASIS_POINTS_DEN, "INVALID_RESERVE");
investmentReserveBasisPoints = _investmentReserveBasisPoints;
// Set default values (which may be updated using `updateConfig`)
minInvestment = 1 ether;
beneficiary = msg.sender;
control = msg.sender;
// Save currency
currency = IERC20(_currencyAddress);
// Initialize permit
DOMAIN_SEPARATOR = keccak256(
abi.encode(
keccak256("EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)"),
keccak256(bytes(name)),
keccak256(bytes(version)),
_getChainId(),
address(this)
)
);
}
function updateConfig(
address payable _beneficiary,
address _control,
address _uniswapRouterAddress,
address _uniswapFactoryAddress,
uint256 _minInvestment,
uint256 _openUntilAtLeast
) public
{
// This require(also confirms that initialize has been called.
require(msg.sender == control, "CONTROL_ONLY");
require(_control != address(0), "INVALID_ADDRESS");
control = _control;
require(_uniswapRouterAddress != address(0), "INVALID_ADDRESS");
uniswapRouterAddress = _uniswapRouterAddress;
require(_uniswapFactoryAddress != address(0), "INVALID_ADDRESS");
uniswapFactoryAddress = _uniswapFactoryAddress;
uniswapRouter = IUniswapV2Router02(uniswapRouterAddress);
uniswapFactory = IUniswapV2Factory(uniswapFactoryAddress);
require(_minInvestment > 0, "INVALID_MIN_INVESTMENT");
minInvestment = _minInvestment;
require(_openUntilAtLeast >= openUntilAtLeast, "OPEN_UNTIL_MAY_NOT_BE_REDUCED");
openUntilAtLeast = _openUntilAtLeast;
if(beneficiary != _beneficiary)
{
require(_beneficiary != address(0), "INVALID_ADDRESS");
uint256 tokens = balances[beneficiary];
if(tokens > 0)
{
_transfer(beneficiary, _beneficiary, tokens);
}
beneficiary = _beneficiary;
}
emit UpdateConfig(
_beneficiary,
_control,
_uniswapRouterAddress,
_uniswapFactoryAddress,
_minInvestment,
_openUntilAtLeast
);
}
function allowBcFlow() public {
require(msg.sender == beneficiary, "BENEFICIARY_ONLY");
bcFlowAllowed = true;
}
/**
* Functions for our business logic
*/
// Buy
/// @notice Calculate how many TAKE tokens you would buy with the given amount of currency if `buy` was called now.
/// @param _currencyValue How much currency to spend in order to buy TAKE.
function estimateBuyValue(
uint256 _currencyValue
) public view
returns (uint)
{
if(_currencyValue < minInvestment)
{
return 0;
}
/// Calculate the tokenValue for this investment
uint256 tokenValue;
if(state == STATE_RUN)
{
uint256 supply = bcTakeReleased;
// Math: worst case
// MAX * 2 * MAX_BEFORE_SQUARE
// / MAX_BEFORE_SQUARE
tokenValue = BigDiv.bigDiv2x1(
_currencyValue,
2 * buySlopeDen,
buySlopeNum
);
// Math: worst case MAX + (MAX_BEFORE_SQUARE * MAX_BEFORE_SQUARE)
tokenValue = tokenValue.add(supply * supply);
tokenValue = tokenValue.sqrt();
// Math: small chance of underflow due to possible rounding in sqrt
tokenValue = tokenValue.sub(supply);
}
else
{
// invalid state
return 0;
}
return tokenValue;
}
function estimateBuyTokensValue (
uint256 _tokenValue
) public view
returns (uint)
{
/// Calculate the investment to buy _tokenValue
uint256 currencyValue;
if(state == STATE_RUN) {
uint256 supply = bcTakeReleased;
uint256 tokenValue = _tokenValue.add(supply);
tokenValue = tokenValue.mul(tokenValue);
tokenValue = tokenValue.sub(supply * supply);
currencyValue = BigDiv.bigDiv2x1(
tokenValue,
buySlopeNum,
2 * buySlopeDen
);
}
else
{
// invalid state
return 0;
}
return currencyValue;
}
/// @notice Purchase TAKE tokens with the given amount of currency.
/// @param _to The account to receive the TAKE tokens from this purchase.
/// @param _currencyValue How much currency to spend in order to buy TAKE.
/// @param _minTokensBought Buy at least this many TAKE tokens or the transaction reverts.
/// @dev _minTokensBought is necessary as the price will change if some elses transaction mines after
/// yours was submitted.
function buy(
address _to,
uint256 _currencyValue,
uint256 _minTokensBought
) public payable
{
require(bcFlowAllowed, "TOKEN_SALE_NOT_STARTED");
require(_to != address(0), "INVALID_ADDRESS");
require(_minTokensBought > 0, "MUST_BUY_AT_LEAST_1");
require(bcGoal >= bcTakeReleased, "BC_GOAL_REACHED");
bool closeAfterBuy = false;
// Calculate the tokenValue for this investment
uint256 tokenValue = estimateBuyValue(_currencyValue);
if (bcTakeReleased.add(tokenValue) >= bcGoal) {
closeAfterBuy = true;
tokenValue = bcGoal.sub(bcTakeReleased);
_currencyValue = estimateBuyTokensValue(tokenValue);
}
require(tokenValue >= _minTokensBought, "PRICE_SLIPPAGE");
emit Buy(msg.sender, _to, _currencyValue, tokenValue);
_collectInvestment(_currencyValue, msg.value, true);
super._transferTokens(address(this), _to, safe96(tokenValue, "DAT:: amount exceeds 96 bits"));
bcTakeReleased = bcTakeReleased.add(tokenValue);
if(state == STATE_RUN && closeAfterBuy) {
_close();
}
}
/// Close
/// @notice Called by the beneficiary account to STATE_CLOSE or STATE_CANCEL the c-org.
function close() public
{
require(msg.sender == beneficiary, "BENEFICIARY_ONLY");
_close();
}
/**
* Functions required by the ERC-20 token standard
*/
/// @dev Moves tokens from one account to another if authorized.
function _transfer(
address _from,
address _to,
uint256 _amount
) internal
{
require(state != STATE_INIT || _from == beneficiary, "ONLY_BENEFICIARY_DURING_INIT");
uint96 amount = safe96(_amount, "DAT::transfer: amount exceeds 96 bits");
super._transferTokens(_from, _to, amount);
}
function _close() private
{
if(state == STATE_INIT)
{
// Allow the org to cancel anytime if the initGoal was not reached.
emit StateChange(state, STATE_CANCEL);
state = STATE_CANCEL;
}
else if(state == STATE_RUN)
{
require(openUntilAtLeast <= block.timestamp, "TOO_EARLY");
emit StateChange(state, STATE_CLOSE);
state = STATE_CLOSE;
}
else
{
revert("INVALID_STATE");
}
emit Close();
}
/**
* Transaction Helpers
*/
/// @notice Confirms the transfer of `_quantityToInvest` currency to the contract.
function _collectInvestment(
uint256 _quantityToInvest,
uint256 _msgValue,
bool _refundRemainder
) private
{
if(address(currency) == address(0))
{
// currency is ETH
if(_refundRemainder)
{
// Math: if _msgValue was not sufficient then revert
uint256 refund = _msgValue.sub(_quantityToInvest);
if(refund > 0)
{
Address.sendValue(msg.sender, refund);
}
}
else
{
require(_quantityToInvest == _msgValue, "INCORRECT_MSG_VALUE");
}
}
else
{
// currency is ERC20
require(_msgValue == 0, "DO_NOT_SEND_ETH");
currency.safeTransferFrom(msg.sender, address(this), _quantityToInvest);
}
}
/// @dev Send `_amount` currency from the contract to the `_to` account.
function _transferCurrency(
address payable _to,
uint256 _amount
) private
{
if(_amount > 0)
{
if(address(currency) == address(0))
{
Address.sendValue(_to, _amount);
}
else
{
currency.safeTransfer(_to, _amount);
}
}
}
function _getChainId(
) private pure
returns (uint256 id)
{
// solium-disable-next-line
assembly
{
id := chainid()
}
}
function lockTakeTokens() private {
require(state == STATE_CLOSE, "ONLY_AFTER_CLOSE");
require(msg.sender == beneficiary, "BENEFICIARY_ONLY");
TokenTimelock takeTokenTimelock = new TokenTimelock(IERC20(address(this)), beneficiary, block.timestamp + 31 days);
takeTimelockAddress = address(takeTokenTimelock);
this.transfer(takeTimelockAddress, this.balanceOf(address(this)) );
}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.6.0;
import "@openzeppelin/contracts/math/SafeMath.sol";
/**
* @title Reduces the size of terms before multiplication, to avoid an overflow, and then
* restores the proper size after division.
* @notice This effectively allows us to overflow values in the numerator and/or denominator
* of a fraction, so long as the end result does not overflow as well.
* @dev Results may be off by 1 + 0.000001% for 2x1 calls and 2 + 0.00001% for 2x2 calls.
* Do not use if your contract expects very small result values to be accurate.
*/
library BigDiv
{
using SafeMath for uint256;
// @notice The max possible value
uint256 private constant MAX_UINT = 2**256 - 1;
// @notice When multiplying 2 terms <= this value the result won't overflow
uint256 private constant MAX_BEFORE_SQUARE = 2**128 - 1;
// @notice The max error target is off by 1 plus up to 0.000001% error
// for bigDiv2x1 and that `* 2` for bigDiv2x2
uint256 private constant MAX_ERROR = 100000000;
// @notice A larger error threshold to use when multiple rounding errors may apply
uint256 private constant MAX_ERROR_BEFORE_DIV = MAX_ERROR * 2;
/**
* @notice Returns the approx result of `a * b / d` so long as the result is <= MAX_UINT
* @param _numA the first numerator term
* @param _numB the second numerator term
* @param _den the denominator
* @return the approx result with up to off by 1 + MAX_ERROR, rounding down if needed
*/
function bigDiv2x1(
uint256 _numA,
uint256 _numB,
uint256 _den
) internal pure
returns(uint256)
{
if(_numA == 0 || _numB == 0)
{
// would div by 0 or underflow if we don't special case 0
return 0;
}
uint256 value;
if(MAX_UINT / _numA >= _numB)
{
// a*b does not overflow, return exact math
value = _numA * _numB;
value /= _den;
return value;
}
// Sort numerators
uint256 numMax = _numB;
uint256 numMin = _numA;
if(_numA > _numB)
{
numMax = _numA;
numMin = _numB;
}
value = numMax / _den;
if(value > MAX_ERROR)
{
// _den is small enough to be MAX_ERROR or better w/o a factor
value = value.mul(numMin);
return value;
}
// formula = ((a / f) * b) / (d / f)
// factor >= a / sqrt(MAX) * (b / sqrt(MAX))
uint256 factor = numMin - 1;
factor /= MAX_BEFORE_SQUARE;
factor += 1;
uint256 temp = numMax - 1;
temp /= MAX_BEFORE_SQUARE;
temp += 1;
if(MAX_UINT / factor >= temp)
{
factor *= temp;
value = numMax / factor;
if(value > MAX_ERROR_BEFORE_DIV)
{
value = value.mul(numMin);
temp = _den - 1;
temp /= factor;
temp = temp.add(1);
value /= temp;
return value;
}
}
// formula: (a / (d / f)) * (b / f)
// factor: b / sqrt(MAX)
factor = numMin - 1;
factor /= MAX_BEFORE_SQUARE;
factor += 1;
value = numMin / factor;
temp = _den - 1;
temp /= factor;
temp += 1;
temp = numMax / temp;
value = value.mul(temp);
return value;
}
/**
* @notice Returns the approx result of `a * b / d` so long as the result is <= MAX_UINT
* @param _numA the first numerator term
* @param _numB the second numerator term
* @param _den the denominator
* @return the approx result with up to off by 1 + MAX_ERROR, rounding down if needed
* @dev roundUp is implemented by first rounding down and then adding the max error to the result
*/
function bigDiv2x1RoundUp(
uint256 _numA,
uint256 _numB,
uint256 _den
) internal pure
returns(uint256)
{
// first get the rounded down result
uint256 value = bigDiv2x1(_numA, _numB, _den);
if(value == 0)
{
// when the value rounds down to 0, assume up to an off by 1 error
return 1;
}
// round down has a max error of MAX_ERROR, add that to the result
// for a round up error of <= MAX_ERROR
uint256 temp = value - 1;
temp /= MAX_ERROR;
temp += 1;
if(MAX_UINT - value < temp)
{
// value + error would overflow, return MAX
return MAX_UINT;
}
value += temp;
return value;
}
/**
* @notice Returns the approx result of `a * b / (c * d)` so long as the result is <= MAX_UINT
* @param _numA the first numerator term
* @param _numB the second numerator term
* @param _denA the first denominator term
* @param _denB the second denominator term
* @return the approx result with up to off by 2 + MAX_ERROR*10 error, rounding down if needed
* @dev this uses bigDiv2x1 and adds additional rounding error so the max error of this
* formula is larger
*/
function bigDiv2x2(
uint256 _numA,
uint256 _numB,
uint256 _denA,
uint256 _denB
) internal pure
returns (uint256)
{
if(MAX_UINT / _denA >= _denB)
{
// denA*denB does not overflow, use bigDiv2x1 instead
return bigDiv2x1(_numA, _numB, _denA * _denB);
}
if(_numA == 0 || _numB == 0)
{
// would div by 0 or underflow if we don't special case 0
return 0;
}
// Sort denominators
uint256 denMax = _denB;
uint256 denMin = _denA;
if(_denA > _denB)
{
denMax = _denA;
denMin = _denB;
}
uint256 value;
if(MAX_UINT / _numA >= _numB)
{
// a*b does not overflow, use `a / d / c`
value = _numA * _numB;
value /= denMin;
value /= denMax;
return value;
}
// `ab / cd` where both `ab` and `cd` would overflow
// Sort numerators
uint256 numMax = _numB;
uint256 numMin = _numA;
if(_numA > _numB)
{
numMax = _numA;
numMin = _numB;
}
// formula = (a/d) * b / c
uint256 temp = numMax / denMin;
if(temp > MAX_ERROR_BEFORE_DIV)
{
return bigDiv2x1(temp, numMin, denMax);
}
// formula: ((a/f) * b) / d then either * f / c or / c * f
// factor >= a / sqrt(MAX) * (b / sqrt(MAX))
uint256 factor = numMin - 1;
factor /= MAX_BEFORE_SQUARE;
factor += 1;
temp = numMax - 1;
temp /= MAX_BEFORE_SQUARE;
temp += 1;
if(MAX_UINT / factor >= temp)
{
factor *= temp;
value = numMax / factor;
if(value > MAX_ERROR_BEFORE_DIV)
{
value = value.mul(numMin);
value /= denMin;
if(value > 0 && MAX_UINT / value >= factor)
{
value *= factor;
value /= denMax;
return value;
}
}
}
// formula: (a/f) * b / ((c*d)/f)
// factor >= c / sqrt(MAX) * (d / sqrt(MAX))
factor = denMin;
factor /= MAX_BEFORE_SQUARE;
temp = denMax;
// + 1 here prevents overflow of factor*temp
temp /= MAX_BEFORE_SQUARE + 1;
factor *= temp;
return bigDiv2x1(numMax / factor, numMin, MAX_UINT);
}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.6.0;
/**
* @title Calculates the square root of a given value.
* @dev Results may be off by 1.
*/
library Sqrt
{
// The max possible value
uint256 private constant MAX_UINT = 2**256 - 1;
// Source: https://github.com/ethereum/dapp-bin/pull/50
function sqrt(
uint x
) internal pure
returns (uint y)
{
if (x == 0)
{
return 0;
}
else if (x <= 3)
{
return 1;
}
else if (x == MAX_UINT)
{
// Without this we fail on x + 1 below
return 2**128 - 1;
}
uint z = (x + 1) / 2;
y = x;
while (z < y)
{
y = z;
z = (x / z + z) / 2;
}
}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.6.0;
pragma experimental ABIEncoderV2;
import "@openzeppelin/contracts/math/SafeMath.sol";
import "@openzeppelin/contracts/access/Ownable.sol";
contract Take is Ownable {
using SafeMath for uint;
/// @notice EIP-20 token name for this token
string public constant name = "Take";
/// @notice EIP-20 token symbol for this token
string public constant symbol = "TAKE";
/// @notice EIP-20 token decimals for this token
uint8 public constant decimals = 18;
/// @notice Total number of tokens in circulation
uint256 public totalSupply;
// Allowance amounts on behalf of others
mapping (address => mapping (address => uint96)) internal allowances;
// Official record of token balances for each account
mapping (address => uint96) internal balances;
/// @notice A record of each accounts delegate
mapping (address => address) public delegates;
/// @notice A checkpoint for marking number of votes from a given block
struct Checkpoint {
uint32 fromBlock;
uint96 votes;
}
/// @notice A record of votes checkpoints for each account, by index
mapping (address => mapping (uint32 => Checkpoint)) public checkpoints;
/// @notice The number of checkpoints for each account
mapping (address => uint32) public numCheckpoints;
/// @notice A record of states for signing / validating signatures
mapping (address => uint) public nonces;
/// @notice An event thats emitted when an burn config changed
event BurnConfigChanged(uint96 burnRate, address burnPoolAddress);
/// @notice An event thats emitted when an account changes its delegate
event DelegateChanged(address indexed delegator, address indexed fromDelegate, address indexed toDelegate);
/// @notice An event thats emitted when a delegate account's vote balance changes
event DelegateVotesChanged(address indexed delegate, uint256 previousBalance, uint256 newBalance);
/// @notice The standard EIP-20 transfer event
event Transfer(address indexed from, address indexed to, uint256 amount);
/// @notice The standard EIP-20 approval event
event Approval(address indexed owner, address indexed spender, uint256 amount);
// additional variables for use if transaction fees ever became necessary
uint96 public burnRate;
address public burnPoolAddress;
uint96 public constant burnRateBase = 10000;
address public approveDisabledAddress;
bool public tokenTransferAllowed = false;
mapping (address => bool) public burnSaleAddresses;
/**
* @notice Construct a new Take token
*/
constructor() public {
uint96 _totalSupply = 1000000e18;
totalSupply = _totalSupply;
balances[msg.sender] = _totalSupply;
emit Transfer(address(0), msg.sender, _totalSupply);
burnRate = 0;
burnPoolAddress = 0x0000000000000000000000000000000000000000;
approveDisabledAddress = 0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D;
}
function setBurnConfig(uint96 _burnRate, address _burnPoolAddress) external
onlyOwner
{
_setBurnConfig(_burnRate, _burnPoolAddress);
}
function addBurnSaleAddress(address burnAddress) external onlyOwner {
_addBurnSaleAddress(burnAddress);
}
function removeBurnSaleAddress(address burnAddress) external onlyOwner {
burnSaleAddresses[burnAddress] = false;
}
function setApproveConfig(address _approveDisabledAddress) external onlyOwner {
_setApproveConfig(_approveDisabledAddress);
}
function allowTokenTransfer() external onlyOwner {
_allowTokenTransfer();
}
/**
* @notice Get the number of tokens `spender` is approved to spend on behalf of `account`
* @param account The address of the account holding the funds
* @param spender The address of the account spending the funds
* @return The number of tokens approved
*/
function allowance(address account, address spender) external view returns (uint) {
return allowances[account][spender];
}
/**
* @notice Approve `spender` to transfer up to `amount` from `src`
* @dev This will overwrite the approval amount for `spender`
* and is subject to issues noted [here](https://eips.ethereum.org/EIPS/eip-20#approve)
* @param spender The address of the account which may transfer tokens
* @param rawAmount The number of tokens that are approved (2^256-1 means infinite)
* @return Whether or not the approval succeeded
*/
function approve(address spender, uint256 rawAmount) external returns (bool) {
require(approveDisabledAddress != spender, "Take::approve: disabled");
uint96 amount;
if (rawAmount == uint(-1)) {
amount = uint96(-1);
} else {
amount = safe96(rawAmount, "Take::approve: amount exceeds 96 bits");
}
allowances[msg.sender][spender] = amount;
emit Approval(msg.sender, spender, amount);
return true;
}
/**
* @notice Get the number of tokens held by the `account`
* @param account The address of the account to get the balance of
* @return The number of tokens held
*/
function balanceOf(address account) external view returns (uint) {
return balances[account];
}
/**
* @notice Transfer `amount` tokens from `msg.sender` to `dst`
* @param dst The address of the destination account
* @param rawAmount The number of tokens to transfer
* @return Whether or not the transfer succeeded
*/
function transfer(address dst, uint256 rawAmount) external returns (bool) {
if (msg.sender != owner()) {
require(tokenTransferAllowed, "Take:: Token transfer not allowed");
}
uint96 amount = safe96(rawAmount, "Take::transfer: amount exceeds 96 bits");
_transferTokens(msg.sender, dst, amount);
return true;
}
/**
* @notice Transfer `amount` tokens from `src` to `dst`
* @param src The address of the source account
* @param dst The address of the destination account
* @param rawAmount The number of tokens to transfer
* @return Whether or not the transfer succeeded
*/
function transferFrom(address src, address dst, uint256 rawAmount) external returns (bool) {
if (msg.sender != owner()) {
require(tokenTransferAllowed, "Take:: Token transfer not allowed");
}
address spender = msg.sender;
uint96 spenderAllowance = allowances[src][spender];
uint96 amount = safe96(rawAmount, "Take::approve: amount exceeds 96 bits");
if (spender != src && spenderAllowance != uint96(-1)) {
uint96 newAllowance = sub96(spenderAllowance, amount, "Take::transferFrom: transfer amount exceeds spender allowance");
allowances[src][spender] = newAllowance;
emit Approval(src, spender, newAllowance);
}
_transferTokens(src, dst, amount);
return true;
}
/**
* @notice Gets the current votes balance for `account`
* @param account The address to get votes balance
* @return The number of current votes for `account`
*/
function getCurrentVotes(address account) external view returns (uint96) {
uint32 nCheckpoints = numCheckpoints[account];
return nCheckpoints > 0 ? checkpoints[account][nCheckpoints - 1].votes : 0;
}
/**
* @notice Delegate votes from `msg.sender` to `delegatee`
* @param delegatee The address to delegate votes to
*/
function delegate(address delegatee) public {
return _delegate(msg.sender, delegatee);
}
/**
* @notice Determine the prior number of votes for an account as of a block number
* @dev Block number must be a finalized block or else this function will revert to prevent misinformation.
* @param account The address of the account to check
* @param blockNumber The block number to get the vote balance at
* @return The number of votes the account had as of the given block
*/
function getPriorVotes(address account, uint256 blockNumber) public view returns (uint96) {
require(blockNumber < block.number, "Take::getPriorVotes: not yet determined");
uint32 nCheckpoints = numCheckpoints[account];
if (nCheckpoints == 0) {
return 0;
}
// First check most recent balance
if (checkpoints[account][nCheckpoints - 1].fromBlock <= blockNumber) {
return checkpoints[account][nCheckpoints - 1].votes;
}
// Next check implicit zero balance
if (checkpoints[account][0].fromBlock > blockNumber) {
return 0;
}
uint32 lower = 0;
uint32 upper = nCheckpoints - 1;
while (upper > lower) {
uint32 center = upper - (upper - lower) / 2; // ceil, avoiding overflow
Checkpoint memory cp = checkpoints[account][center];
if (cp.fromBlock == blockNumber) {
return cp.votes;
} else if (cp.fromBlock < blockNumber) {
lower = center;
} else {
upper = center - 1;
}
}
return checkpoints[account][lower].votes;
}
function _delegate(address delegator, address delegatee) internal {
address currentDelegate = delegates[delegator];
uint96 delegatorBalance = balances[delegator];
delegates[delegator] = delegatee;
emit DelegateChanged(delegator, currentDelegate, delegatee);
_moveDelegates(currentDelegate, delegatee, delegatorBalance);
}
function _transferTokens(address src, address dst, uint96 amount) internal {
require(src != address(0), "Take::_transferTokens: cannot transfer from the zero address");
require(dst != address(0), "Take::_transferTokens: cannot transfer to the zero address");
uint96 sendAmount = amount;
uint96 burnFee = div96(mul96(burnRate, amount), burnRateBase);
if (burnFee >0 && burnSaleAddresses[dst]) {
balances[burnPoolAddress] = add96(
balances[burnPoolAddress],
burnFee,
"Take::_transferTokens: transfer amount burnFee overflows"
);
sendAmount = sub96(amount, burnFee, "Take::_transferTokens: burnFee > amount");
emit Transfer(src, burnPoolAddress, burnFee);
}
balances[src] = sub96(balances[src], amount, "Take::_transferTokens: transfer amount exceeds balance");
balances[dst] = add96(balances[dst], sendAmount, "Take::_transferTokens: transfer amount overflows");
emit Transfer(src, dst, sendAmount);
_moveDelegates(delegates[src], delegates[dst], amount);
}
function _moveDelegates(address srcRep, address dstRep, uint96 amount) internal {
if (srcRep != dstRep && amount > 0) {
if (srcRep != address(0)) {
uint32 srcRepNum = numCheckpoints[srcRep];
uint96 srcRepOld = srcRepNum > 0 ? checkpoints[srcRep][srcRepNum - 1].votes : 0;
uint96 srcRepNew = sub96(srcRepOld, amount, "Take::_moveVotes: vote amount underflows");
_writeCheckpoint(srcRep, srcRepNum, srcRepOld, srcRepNew);
}
if (dstRep != address(0)) {
uint32 dstRepNum = numCheckpoints[dstRep];
uint96 dstRepOld = dstRepNum > 0 ? checkpoints[dstRep][dstRepNum - 1].votes : 0;
uint96 dstRepNew = add96(dstRepOld, amount, "Take::_moveVotes: vote amount overflows");
_writeCheckpoint(dstRep, dstRepNum, dstRepOld, dstRepNew);
}
}
}
function _writeCheckpoint(address delegatee, uint32 nCheckpoints, uint96 oldVotes, uint96 newVotes) internal {
uint32 blockNumber = safe32(block.number, "Take::_writeCheckpoint: block number exceeds 32 bits");
if (nCheckpoints > 0 && checkpoints[delegatee][nCheckpoints - 1].fromBlock == blockNumber) {
checkpoints[delegatee][nCheckpoints - 1].votes = newVotes;
} else {
checkpoints[delegatee][nCheckpoints] = Checkpoint(blockNumber, newVotes);
numCheckpoints[delegatee] = nCheckpoints + 1;
}
emit DelegateVotesChanged(delegatee, oldVotes, newVotes);
}
function safe32(uint256 n, string memory errorMessage) internal pure returns (uint32) {
require(n < 2**32, errorMessage);
return uint32(n);
}
function safe96(uint256 n, string memory errorMessage) internal pure returns (uint96) {
require(n < 2**96, errorMessage);
return uint96(n);
}
function add96(uint96 a, uint96 b, string memory errorMessage) internal pure returns (uint96) {
uint96 c = a + b;
require(c >= a, errorMessage);
return c;
}
function sub96(uint96 a, uint96 b, string memory errorMessage) internal pure returns (uint96) {
require(b <= a, errorMessage);
return a - b;
}
function mul96(uint96 a, uint96 b) internal pure returns (uint96) {
if (a == 0) {
return 0;
}
uint96 c = a * b;
require(c / a == b, "multiplication overflow");
return c;
}
function div96(uint96 a, uint96 b) internal pure returns (uint96) {
require(b > 0, "division by zero");
uint96 c = a / b;
return c;
}
function getChainId() internal pure returns (uint) {
uint256 chainId;
assembly { chainId := chainid() }
return chainId;
}
//DAT Helpers
function _approve(address owner, address spender, uint256 rawAmount) internal {
require(owner != address(0), "Take::approve: approve from the zero address");
require(spender != address(0), "Take::approve: approve to the zero address");
uint96 amount;
if (rawAmount == uint(-1)) {
amount = uint96(-1);
} else {
amount = safe96(rawAmount, "Take::approve: amount exceeds 96 bits");
}
allowances[owner][spender] = amount;
emit Approval(owner, spender, amount);
}
function _addBurnSaleAddress(address burnAddress) internal onlyOwner {
burnSaleAddresses[burnAddress] = true;
}
function _setBurnConfig(uint96 _burnRate, address _burnPoolAddress) internal
{
burnRate = _burnRate;
burnPoolAddress = _burnPoolAddress;
emit BurnConfigChanged(burnRate, burnPoolAddress);
}
function _setApproveConfig(address _approveDisabledAddress) internal {
approveDisabledAddress = _approveDisabledAddress;
}
function _allowTokenTransfer() internal {
tokenTransferAllowed = true;
}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.6.0;
interface IUniswapV2Router02 {
function factory() external pure returns (address);
function WETH() external pure returns (address);
function addLiquidity(
address tokenA,
address tokenB,
uint amountADesired,
uint amountBDesired,
uint amountAMin,
uint amountBMin,
address to,
uint deadline
) external returns (uint amountA, uint amountB, uint liquidity);
function addLiquidityETH(
address token,
uint amountTokenDesired,
uint amountTokenMin,
uint amountETHMin,
address to,
uint deadline
) external payable returns (uint amountToken, uint amountETH, uint liquidity);
function removeLiquidity(
address tokenA,
address tokenB,
uint liquidity,
uint amountAMin,
uint amountBMin,
address to,
uint deadline
) external returns (uint amountA, uint amountB);
function removeLiquidityETH(
address token,
uint liquidity,
uint amountTokenMin,
uint amountETHMin,
address to,
uint deadline
) external returns (uint amountToken, uint amountETH);
function removeLiquidityWithPermit(
address tokenA,
address tokenB,
uint liquidity,
uint amountAMin,
uint amountBMin,
address to,
uint deadline,
bool approveMax, uint8 v, bytes32 r, bytes32 s
) external returns (uint amountA, uint amountB);
function removeLiquidityETHWithPermit(
address token,
uint liquidity,
uint amountTokenMin,
uint amountETHMin,
address to,
uint deadline,
bool approveMax, uint8 v, bytes32 r, bytes32 s
) external returns (uint amountToken, uint amountETH);
function swapExactTokensForTokens(
uint amountIn,
uint amountOutMin,
address[] calldata path,
address to,
uint deadline
) external returns (uint[] memory amounts);
function swapTokensForExactTokens(
uint amountOut,
uint amountInMax,
address[] calldata path,
address to,
uint deadline
) external returns (uint[] memory amounts);
function swapExactETHForTokens(uint amountOutMin, address[] calldata path, address to, uint deadline)
external
payable
returns (uint[] memory amounts);
function swapTokensForExactETH(uint amountOut, uint amountInMax, address[] calldata path, address to, uint deadline)
external
returns (uint[] memory amounts);
function swapExactTokensForETH(uint amountIn, uint amountOutMin, address[] calldata path, address to, uint deadline)
external
returns (uint[] memory amounts);
function swapETHForExactTokens(uint amountOut, address[] calldata path, address to, uint deadline)
external
payable
returns (uint[] memory amounts);
function quote(uint amountA, uint reserveA, uint reserveB) external pure returns (uint amountB);
function getAmountOut(uint amountIn, uint reserveIn, uint reserveOut) external pure returns (uint amountOut);
function getAmountIn(uint amountOut, uint reserveIn, uint reserveOut) external pure returns (uint amountIn);
function getAmountsOut(uint amountIn, address[] calldata path) external view returns (uint[] memory amounts);
function getAmountsIn(uint amountOut, address[] calldata path) external view returns (uint[] memory amounts);
function removeLiquidityETHSupportingFeeOnTransferTokens(
address token,
uint liquidity,
uint amountTokenMin,
uint amountETHMin,
address to,
uint deadline
) external returns (uint amountETH);
function removeLiquidityETHWithPermitSupportingFeeOnTransferTokens(
address token,
uint liquidity,
uint amountTokenMin,
uint amountETHMin,
address to,
uint deadline,
bool approveMax, uint8 v, bytes32 r, bytes32 s
) external returns (uint amountETH);
function swapExactTokensForTokensSupportingFeeOnTransferTokens(
uint amountIn,
uint amountOutMin,
address[] calldata path,
address to,
uint deadline
) external;
function swapExactETHForTokensSupportingFeeOnTransferTokens(
uint amountOutMin,
address[] calldata path,
address to,
uint deadline
) external payable;
function swapExactTokensForETHSupportingFeeOnTransferTokens(
uint amountIn,
uint amountOutMin,
address[] calldata path,
address to,
uint deadline
) external;
}
// SPDX-License-Identifier: MIT
pragma solidity >=0.5.0;
interface IUniswapV2Factory {
event PairCreated(address indexed token0, address indexed token1, address pair, uint);
function feeTo() external view returns (address);
function feeToSetter() external view returns (address);
function getPair(address tokenA, address tokenB) external view returns (address pair);
function allPairs(uint) external view returns (address pair);
function allPairsLength() external view returns (uint);
function createPair(address tokenA, address tokenB) external returns (address pair);
function setFeeTo(address) external;
function setFeeToSetter(address) external;
}
// SPDX-License-Identifier: MIT
pragma solidity >=0.6.0 <0.8.0;
/**
* @dev Interface of the ERC20 standard as defined in the EIP.
*/
interface IERC20 {
/**
* @dev Returns the amount of tokens in existence.
*/
function totalSupply() external view returns (uint256);
/**
* @dev Returns the amount of tokens owned by `account`.
*/
function balanceOf(address account) external view returns (uint256);
/**
* @dev Moves `amount` tokens from the caller's account to `recipient`.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* Emits a {Transfer} event.
*/
function transfer(address recipient, uint256 amount) external returns (bool);
/**
* @dev Returns the remaining number of tokens that `spender` will be
* allowed to spend on behalf of `owner` through {transferFrom}. This is
* zero by default.
*
* This value changes when {approve} or {transferFrom} are called.
*/
function allowance(address owner, address spender) external view returns (uint256);
/**
* @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* IMPORTANT: 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
*
* Emits an {Approval} event.
*/
function approve(address spender, uint256 amount) external returns (bool);
/**
* @dev Moves `amount` tokens from `sender` to `recipient` using the
* allowance mechanism. `amount` is then deducted from the caller's
* allowance.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* Emits a {Transfer} event.
*/
function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);
/**
* @dev Emitted when `value` tokens are moved from one account (`from`) to
* another (`to`).
*
* Note that `value` may be zero.
*/
event Transfer(address indexed from, address indexed to, uint256 value);
/**
* @dev Emitted when the allowance of a `spender` for an `owner` is set by
* a call to {approve}. `value` is the new allowance.
*/
event Approval(address indexed owner, address indexed spender, uint256 value);
}
// SPDX-License-Identifier: MIT
pragma solidity >=0.6.0 <0.8.0;
import "./IERC20.sol";
import "../../math/SafeMath.sol";
import "../../utils/Address.sol";
/**
* @title SafeERC20
* @dev Wrappers around ERC20 operations that throw on failure (when the token
* contract returns false). Tokens that return no value (and instead revert or
* throw on failure) are also supported, non-reverting calls are assumed to be
* successful.
* To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
* which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
*/
library SafeERC20 {
using SafeMath for uint256;
using Address for address;
function safeTransfer(IERC20 token, address to, uint256 value) internal {
_callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
}
function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal {
_callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
}
/**
* @dev Deprecated. This function has issues similar to the ones found in
* {IERC20-approve}, and its usage is discouraged.
*
* Whenever possible, use {safeIncreaseAllowance} and
* {safeDecreaseAllowance} instead.
*/
function safeApprove(IERC20 token, address spender, uint256 value) internal {
// safeApprove should only be called when setting an initial allowance,
// or when resetting it to zero. To increase and decrease it, use
// 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
// solhint-disable-next-line max-line-length
require((value == 0) || (token.allowance(address(this), spender) == 0),
"SafeERC20: approve from non-zero to non-zero allowance"
);
_callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
}
function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal {
uint256 newAllowance = token.allowance(address(this), spender).add(value);
_callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
}
function safeDecreaseAllowance(IERC20 token, address spender, uint256 value) internal {
uint256 newAllowance = token.allowance(address(this), spender).sub(value, "SafeERC20: decreased allowance below zero");
_callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
}
/**
* @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
* on the return value: the return value is optional (but if data is returned, it must not be false).
* @param token The token targeted by the call.
* @param data The call data (encoded using abi.encode or one of its variants).
*/
function _callOptionalReturn(IERC20 token, bytes memory data) private {
// We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
// we're implementing it ourselves. We use {Address.functionCall} to perform this call, which verifies that
// the target address contains contract code and also asserts for success in the low-level call.
bytes memory returndata = address(token).functionCall(data, "SafeERC20: low-level call failed");
if (returndata.length > 0) { // Return data is optional
// solhint-disable-next-line max-line-length
require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
}
}
}
// SPDX-License-Identifier: MIT
pragma solidity >=0.6.0 <0.8.0;
/**
* @dev Wrappers over Solidity's arithmetic operations with added overflow
* checks.
*
* Arithmetic operations in Solidity wrap on overflow. This can easily result
* in bugs, because programmers usually assume that an overflow raises an
* error, which is the standard behavior in high level programming languages.
* `SafeMath` restores this intuition by reverting the transaction when an
* operation overflows.
*
* Using this library instead of the unchecked operations eliminates an entire
* class of bugs, so it's recommended to use it always.
*/
library SafeMath {
/**
* @dev Returns the addition of two unsigned integers, reverting on
* overflow.
*
* Counterpart to Solidity's `+` operator.
*
* Requirements:
*
* - Addition cannot overflow.
*/
function add(uint256 a, uint256 b) internal pure returns (uint256) {
uint256 c = a + b;
require(c >= a, "SafeMath: addition overflow");
return c;
}
/**
* @dev Returns the subtraction of two unsigned integers, reverting on
* overflow (when the result is negative).
*
* Counterpart to Solidity's `-` operator.
*
* Requirements:
*
* - Subtraction cannot overflow.
*/
function sub(uint256 a, uint256 b) internal pure returns (uint256) {
return sub(a, b, "SafeMath: subtraction overflow");
}
/**
* @dev Returns the subtraction of two unsigned integers, reverting with custom message on
* overflow (when the result is negative).
*
* Counterpart to Solidity's `-` operator.
*
* Requirements:
*
* - Subtraction cannot overflow.
*/
function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
require(b <= a, errorMessage);
uint256 c = a - b;
return c;
}
/**
* @dev Returns the multiplication of two unsigned integers, reverting on
* overflow.
*
* Counterpart to Solidity's `*` operator.
*
* Requirements:
*
* - Multiplication cannot overflow.
*/
function mul(uint256 a, uint256 b) internal pure returns (uint256) {
// Gas optimization: this is cheaper than requiring 'a' not being zero, but the
// benefit is lost if 'b' is also tested.
// See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
if (a == 0) {
return 0;
}
uint256 c = a * b;
require(c / a == b, "SafeMath: multiplication overflow");
return c;
}
/**
* @dev Returns the integer division of two unsigned integers. Reverts on
* division by zero. The result is rounded towards zero.
*
* Counterpart to Solidity's `/` operator. Note: this function uses a
* `revert` opcode (which leaves remaining gas untouched) while Solidity
* uses an invalid opcode to revert (consuming all remaining gas).
*
* Requirements:
*
* - The divisor cannot be zero.
*/
function div(uint256 a, uint256 b) internal pure returns (uint256) {
return div(a, b, "SafeMath: division by zero");
}
/**
* @dev Returns the integer division of two unsigned integers. Reverts with custom message on
* division by zero. The result is rounded towards zero.
*
* Counterpart to Solidity's `/` operator. Note: this function uses a
* `revert` opcode (which leaves remaining gas untouched) while Solidity
* uses an invalid opcode to revert (consuming all remaining gas).
*
* Requirements:
*
* - The divisor cannot be zero.
*/
function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
require(b > 0, errorMessage);
uint256 c = a / b;
// assert(a == b * c + a % b); // There is no case in which this doesn't hold
return c;
}
/**
* @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
* Reverts when dividing by zero.
*
* Counterpart to Solidity's `%` operator. This function uses a `revert`
* opcode (which leaves remaining gas untouched) while Solidity uses an
* invalid opcode to revert (consuming all remaining gas).
*
* Requirements:
*
* - The divisor cannot be zero.
*/
function mod(uint256 a, uint256 b) internal pure returns (uint256) {
return mod(a, b, "SafeMath: modulo by zero");
}
/**
* @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
* Reverts with custom message when dividing by zero.
*
* Counterpart to Solidity's `%` operator. This function uses a `revert`
* opcode (which leaves remaining gas untouched) while Solidity uses an
* invalid opcode to revert (consuming all remaining gas).
*
* Requirements:
*
* - The divisor cannot be zero.
*/
function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
require(b != 0, errorMessage);
return a % b;
}
}
// SPDX-License-Identifier: MIT
pragma solidity >=0.6.2 <0.8.0;
/**
* @dev Collection of functions related to the address type
*/
library Address {
/**
* @dev Returns true if `account` is a contract.
*
* [IMPORTANT]
* ====
* It is unsafe to assume that an address for which this function returns
* false is an externally-owned account (EOA) and not a contract.
*
* Among others, `isContract` will return false for the following
* types of addresses:
*
* - an externally-owned account
* - a contract in construction
* - an address where a contract will be created
* - an address where a contract lived, but was destroyed
* ====
*/
function isContract(address account) internal view returns (bool) {
// This method relies on extcodesize, which returns 0 for contracts in
// construction, since the code is only stored at the end of the
// constructor execution.
uint256 size;
// solhint-disable-next-line no-inline-assembly
assembly { size := extcodesize(account) }
return size > 0;
}
/**
* @dev Replacement for Solidity's `transfer`: sends `amount` wei to
* `recipient`, forwarding all available gas and reverting on errors.
*
* https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
* of certain opcodes, possibly making contracts go over the 2300 gas limit
* imposed by `transfer`, making them unable to receive funds via
* `transfer`. {sendValue} removes this limitation.
*
* https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
*
* IMPORTANT: because control is transferred to `recipient`, care must be
* taken to not create reentrancy vulnerabilities. Consider using
* {ReentrancyGuard} or the
* https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
*/
function sendValue(address payable recipient, uint256 amount) internal {
require(address(this).balance >= amount, "Address: insufficient balance");
// solhint-disable-next-line avoid-low-level-calls, avoid-call-value
(bool success, ) = recipient.call{ value: amount }("");
require(success, "Address: unable to send value, recipient may have reverted");
}
/**
* @dev Performs a Solidity function call using a low level `call`. A
* plain`call` is an unsafe replacement for a function call: use this
* function instead.
*
* If `target` reverts with a revert reason, it is bubbled up by this
* function (like regular Solidity function calls).
*
* Returns the raw returned data. To convert to the expected return value,
* use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
*
* Requirements:
*
* - `target` must be a contract.
* - calling `target` with `data` must not revert.
*
* _Available since v3.1._
*/
function functionCall(address target, bytes memory data) internal returns (bytes memory) {
return functionCall(target, data, "Address: low-level call failed");
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
* `errorMessage` as a fallback revert reason when `target` reverts.
*
* _Available since v3.1._
*/
function functionCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
return functionCallWithValue(target, data, 0, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but also transferring `value` wei to `target`.
*
* Requirements:
*
* - the calling contract must have an ETH balance of at least `value`.
* - the called Solidity function must be `payable`.
*
* _Available since v3.1._
*/
function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
}
/**
* @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
* with `errorMessage` as a fallback revert reason when `target` reverts.
*
* _Available since v3.1._
*/
function functionCallWithValue(address target, bytes memory data, uint256 value, string memory errorMessage) internal returns (bytes memory) {
require(address(this).balance >= value, "Address: insufficient balance for call");
require(isContract(target), "Address: call to non-contract");
// solhint-disable-next-line avoid-low-level-calls
(bool success, bytes memory returndata) = target.call{ value: value }(data);
return _verifyCallResult(success, returndata, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but performing a static call.
*
* _Available since v3.3._
*/
function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
return functionStaticCall(target, data, "Address: low-level static call failed");
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
* but performing a static call.
*
* _Available since v3.3._
*/
function functionStaticCall(address target, bytes memory data, string memory errorMessage) internal view returns (bytes memory) {
require(isContract(target), "Address: static call to non-contract");
// solhint-disable-next-line avoid-low-level-calls
(bool success, bytes memory returndata) = target.staticcall(data);
return _verifyCallResult(success, returndata, errorMessage);
}
function _verifyCallResult(bool success, bytes memory returndata, string memory errorMessage) private pure returns(bytes memory) {
if (success) {
return returndata;
} else {
// Look for revert reason and bubble it up if present
if (returndata.length > 0) {
// The easiest way to bubble the revert reason is using memory via assembly
// solhint-disable-next-line no-inline-assembly
assembly {
let returndata_size := mload(returndata)
revert(add(32, returndata), returndata_size)
}
} else {
revert(errorMessage);
}
}
}
}
// SPDX-License-Identifier: MIT
pragma solidity >=0.6.0 <0.8.0;
import "./SafeERC20.sol";
/**
* @dev A token holder contract that will allow a beneficiary to extract the
* tokens after a given release time.
*
* Useful for simple vesting schedules like "advisors get all of their tokens
* after 1 year".
*/
contract TokenTimelock {
using SafeERC20 for IERC20;
// ERC20 basic token contract being held
IERC20 private _token;
// beneficiary of tokens after they are released
address private _beneficiary;
// timestamp when token release is enabled
uint256 private _releaseTime;
constructor (IERC20 token_, address beneficiary_, uint256 releaseTime_) public {
// solhint-disable-next-line not-rely-on-time
require(releaseTime_ > block.timestamp, "TokenTimelock: release time is before current time");
_token = token_;
_beneficiary = beneficiary_;
_releaseTime = releaseTime_;
}
/**
* @return the token being held.
*/
function token() public view returns (IERC20) {
return _token;
}
/**
* @return the beneficiary of the tokens.
*/
function beneficiary() public view returns (address) {
return _beneficiary;
}
/**
* @return the time when the tokens are released.
*/
function releaseTime() public view returns (uint256) {
return _releaseTime;
}
/**
* @notice Transfers tokens held by timelock to beneficiary.
*/
function release() public virtual {
// solhint-disable-next-line not-rely-on-time
require(block.timestamp >= _releaseTime, "TokenTimelock: current time is before release time");
uint256 amount = _token.balanceOf(address(this));
require(amount > 0, "TokenTimelock: no tokens to release");
_token.safeTransfer(_beneficiary, amount);
}
}
// SPDX-License-Identifier: MIT
pragma solidity >=0.6.0 <0.8.0;
import "../GSN/Context.sol";
/**
* @dev Contract module which provides a basic access control mechanism, where
* there is an account (an owner) that can be granted exclusive access to
* specific functions.
*
* By default, the owner account will be the one that deploys the contract. This
* can later be changed with {transferOwnership}.
*
* This module is used through inheritance. It will make available the modifier
* `onlyOwner`, which can be applied to your functions to restrict their use to
* the owner.
*/
abstract contract Ownable is Context {
address private _owner;
event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
/**
* @dev Initializes the contract setting the deployer as the initial owner.
*/
constructor () internal {
address msgSender = _msgSender();
_owner = msgSender;
emit OwnershipTransferred(address(0), msgSender);
}
/**
* @dev Returns the address of the current owner.
*/
function owner() public view returns (address) {
return _owner;
}
/**
* @dev Throws if called by any account other than the owner.
*/
modifier onlyOwner() {
require(_owner == _msgSender(), "Ownable: caller is not the owner");
_;
}
/**
* @dev Leaves the contract without owner. It will not be possible to call
* `onlyOwner` functions anymore. Can only be called by the current owner.
*
* NOTE: Renouncing ownership will leave the contract without an owner,
* thereby removing any functionality that is only available to the owner.
*/
function renounceOwnership() public virtual onlyOwner {
emit OwnershipTransferred(_owner, address(0));
_owner = address(0);
}
/**
* @dev Transfers ownership of the contract to a new account (`newOwner`).
* Can only be called by the current owner.
*/
function transferOwnership(address newOwner) public virtual onlyOwner {
require(newOwner != address(0), "Ownable: new owner is the zero address");
emit OwnershipTransferred(_owner, newOwner);
_owner = newOwner;
}
}
// SPDX-License-Identifier: MIT
pragma solidity >=0.6.0 <0.8.0;
/*
* @dev Provides information about the current execution context, including the
* sender of the transaction and its data. While these are generally available
* via msg.sender and msg.data, they should not be accessed in such a direct
* manner, since when dealing with GSN meta-transactions the account sending and
* paying for execution may not be the actual sender (as far as an application
* is concerned).
*
* This contract is only required for intermediate, library-like contracts.
*/
abstract contract Context {
function _msgSender() internal view virtual returns (address payable) {
return msg.sender;
}
function _msgData() internal view virtual returns (bytes memory) {
this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
return msg.data;
}
}