Contract Name:
ScratchToken
Contract Source Code:
// SPDX-License-Identifier: UNLICENSED
/**
* Copyright © 2022 Scratch Engine LLC. All rights reserved.
* Limited license is afforded to Etherscan, in accordance with its Terms of Use,
* in order to publish this material.
* In connection with the foregoing, redistribution and use on the part of Etherscan,
* in source and binary forms, without modification, are permitted,
* provided that such redistributions of source code retain the foregoing copyright notice
* and this disclaimer.
*/
pragma solidity 0.8.4;
// import "hardhat/console.sol";
// Openzeppelin
import "@openzeppelin/contracts/token/ERC20/extensions/ERC20Burnable.sol";
import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/utils/Address.sol";
// Uniswap
import "@uniswap/v2-core/contracts/interfaces/IUniswapV2Pair.sol";
import "@uniswap/v2-core/contracts/interfaces/IUniswapV2Factory.sol";
import "@uniswap/v2-periphery/contracts/interfaces/IUniswapV2Router02.sol";
import "./FoundersTimelock.sol";
/**
* @title ScratchToken
* @dev An ERC20 token featuring fees-on-transfer for buy/sell transactions
* and increased fees on larger sell transactions.
*/
contract ScratchToken is Context, IERC20, Ownable {
using Address for address;
// ERC20
string private constant _NAME = "ScratchToken";
string private constant _SYMBOL = "SCRATCH";
uint8 private constant _DECIMALS = 9;
uint256 private constant _MAX_SUPPLY = 100 * 10**15 * 10 ** _DECIMALS;
uint256 private _totalSupply;
mapping(address => uint256) private _balances;
mapping(address => mapping(address => uint256)) private _allowances;
// All percentages are relative to this value (1/10,000)
uint256 private constant _PERCENTAGE_RELATIVE_TO = 10000;
/// Distribution
uint256 private constant _DIST_BURN_PERCENTAGE = 1850;
uint256 private constant _DIST_FOUNDER1_PERCENTAGE = 250;
uint256 private constant _DIST_FOUNDER2_PERCENTAGE = 250;
uint256 private constant _DIST_FOUNDER3_PERCENTAGE = 250;
uint256 private constant _DIST_FOUNDER4_PERCENTAGE = 250;
uint256 private constant _DIST_FOUNDER5_PERCENTAGE = 250;
uint256 private constant _DIST_EXCHANGE_PERCENTAGE = 750;
uint256 private constant _DIST_DEV_PERCENTAGE = 500;
uint256 private constant _DIST_OPS_PERCENTAGE = 150;
// Founders TimeLock
uint256 private constant _FOUNDERS_CLIFF_DURATION = 30 days * 6; // 6 months
uint256 private constant _FOUNDERS_VESTING_PERIOD = 30 days; // Release every 30 days
uint8 private constant _FOUNDERS_VESTING_DURATION = 10; // Linear release 10 times every 30 days
mapping(address => FoundersTimelock) public foundersTimelocks;
event FounderLiquidityLocked (
address wallet,
address timelockContract,
uint256 tokensAmount
);
// Fees
uint256 private constant _TAX_NORMAL_DEV_PERCENTAGE = 200;
uint256 private constant _TAX_NORMAL_LIQUIDITY_PERCENTAGE = 200;
uint256 private constant _TAX_NORMAL_OPS_PERCENTAGE = 100;
uint256 private constant _TAX_NORMAL_ARCHA_PERCENTAGE = 100;
uint256 private constant _TAX_EXTRA_LIQUIDITY_PERCENTAGE = 1000;
uint256 private constant _TAX_EXTRA_BURN_PERCENTAGE = 500;
uint256 private constant _TAX_EXTRA_DEV_PERCENTAGE = 500;
uint256 private constant _TOKEN_STABILITY_PROTECTION_THRESHOLD_PERCENTAGE = 200;
bool private _devFeeEnabled = true;
bool private _opsFeeEnabled = true;
bool private _liquidityFeeEnabled = true;
bool private _archaFeeEnabled = true;
bool private _burnFeeEnabled = true;
bool private _tokenStabilityProtectionEnabled = true;
mapping (address => bool) private _isExcludedFromFee;
address private immutable _developmentWallet;
address private _operationsWallet;
address private _archaWallet;
// Accumulated unswaped tokens from fee
uint256 private _devFeePendingSwap = 0;
uint256 private _opsFeePendingSwap = 0;
uint256 private _liquidityFeePendingSwap = 0;
// Uniswap
uint256 private constant _UNISWAP_DEADLINE_DELAY = 60; // in seconds
IUniswapV2Router02 private _uniswapV2Router;
IUniswapV2Pair private _uniswapV2Pair;
address private immutable _lpTokensWallet;
bool private _inSwap = false; // Whether a previous call of swap process is still in process.
bool private _swapAndLiquifyEnabled = true;
uint256 private _minTokensBeforeSwapAndLiquify = 1 * 10 ** _DECIMALS;
address private _liquidityWallet = 0x0000000000000000000000000000000000000000;
// Events
event SwapAndLiquify(
uint256 tokensSwapped,
uint256 ethReceived,
uint256 tokensAddedToLiquidity
);
event SwapAndLiquifyEnabledUpdated(bool enabled);
event MinTokensBeforeSwapUpdated(uint256 minTokensBeforeSwap);
event DevFeeEnabledUpdated(bool enabled);
event OpsFeeEnabledUpdated(bool enabled);
event LiquidityFeeEnabledUpdated(bool enabled);
event ArchaFeeEnabledUpdated(bool enabled);
event BurnFeeEnabledUpdated(bool enabled);
event TokenStabilityProtectionEnabledUpdated(bool enabled);
event ExclusionFromFeesUpdated(address account, bool isExcluded);
event ArchaWalletUpdated(address newWallet);
event LiquidityWalletUpdated(address newWallet);
// Modifiers
modifier lockTheSwap {
require(!_inSwap, "Currently in swap.");
_inSwap = true;
_;
_inSwap = false;
}
// Fallback function to recieve ETH from uniswapV2Router when swaping
receive() external payable {}
constructor (
address owner,
address founder1Wallet_,
address founder2Wallet_,
address founder3Wallet_,
address founder4Wallet_,
address founder5Wallet_,
address developmentWallet_,
address exchangeWallet_,
address operationsWallet_,
address archaWallet_,
address uniswapV2RouterAddress_
) {
require(developmentWallet_ != address(0), "ScratchToken: set wallet to the zero address");
require(exchangeWallet_ != address(0), "ScratchToken: set wallet to the zero address");
require(operationsWallet_ != address(0), "ScratchToken: set wallet to the zero address");
require(archaWallet_ != address(0), "ScratchToken: set wallet to the zero address");
// Exclude addresses from fee
_isExcludedFromFee[owner] = true;
_isExcludedFromFee[address(this)] = true;
_isExcludedFromFee[founder1Wallet_] = true;
_isExcludedFromFee[founder2Wallet_] = true;
_isExcludedFromFee[founder3Wallet_] = true;
_isExcludedFromFee[founder4Wallet_] = true;
_isExcludedFromFee[founder5Wallet_] = true;
_isExcludedFromFee[developmentWallet_] = true;
_isExcludedFromFee[exchangeWallet_] = true;
_isExcludedFromFee[operationsWallet_] = true;
_isExcludedFromFee[archaWallet_] = true;
/// Perform initial distribution
// Founders
_lockFounderLiquidity(founder1Wallet_, _DIST_FOUNDER1_PERCENTAGE);
_lockFounderLiquidity(founder2Wallet_, _DIST_FOUNDER2_PERCENTAGE);
_lockFounderLiquidity(founder3Wallet_, _DIST_FOUNDER3_PERCENTAGE);
_lockFounderLiquidity(founder4Wallet_, _DIST_FOUNDER4_PERCENTAGE);
_lockFounderLiquidity(founder5Wallet_, _DIST_FOUNDER5_PERCENTAGE);
// Exchange
_mint(exchangeWallet_, _getAmountToDistribute(_DIST_EXCHANGE_PERCENTAGE));
_lpTokensWallet = exchangeWallet_;
// Dev
_mint(developmentWallet_, _getAmountToDistribute(_DIST_DEV_PERCENTAGE));
_developmentWallet = developmentWallet_;
// Operations
_mint(operationsWallet_, _getAmountToDistribute(_DIST_OPS_PERCENTAGE));
_operationsWallet = operationsWallet_;
// Archa (used later for taxes)
_archaWallet = archaWallet_;
// Burn
uint256 burnAmount = _getAmountToDistribute(_DIST_BURN_PERCENTAGE);
emit Transfer(address(0), address(0), burnAmount);
// Send the rest of supply minus burn to owner
_mint(owner, _MAX_SUPPLY - totalSupply() - burnAmount);
// Initialize uniswap
_initSwap(uniswapV2RouterAddress_);
// Transfer ownership to owner
transferOwnership(owner);
}
// Constructor Internal Methods
function _getAmountToDistribute(uint256 distributionPercentage) private pure returns (uint256) {
return (_MAX_SUPPLY * distributionPercentage) / _PERCENTAGE_RELATIVE_TO;
}
function _lockFounderLiquidity(address wallet, uint256 distributionPercentage) internal {
FoundersTimelock timelockContract = new FoundersTimelock(this, wallet, _FOUNDERS_CLIFF_DURATION, _FOUNDERS_VESTING_PERIOD, _FOUNDERS_VESTING_DURATION);
foundersTimelocks[wallet] = timelockContract;
_isExcludedFromFee[address(timelockContract)] = true;
_mint(address(timelockContract), _getAmountToDistribute(distributionPercentage));
emit FounderLiquidityLocked(wallet, address(timelockContract), _getAmountToDistribute(distributionPercentage));
}
// Public owner methods
function isExcludedFromFees(address account) external view returns (bool) {
return _isExcludedFromFee[account];
}
function excludeFromFees(address account, bool isExcluded) external onlyOwner {
_isExcludedFromFee[account] = isExcluded;
emit ExclusionFromFeesUpdated(account, isExcluded);
}
/**
* @dev Returns the address of the archa wallet.
*/
function archaWallet() external view returns (address) {
return _archaWallet;
}
/**
* @dev Sets the address of the archa wallet.
*/
function setArchaWallet(address newWallet) external onlyOwner {
require(newWallet != address(0), "ScratchToken: set wallet to the zero address");
_archaWallet = newWallet;
emit ArchaWalletUpdated(newWallet);
}
/**
* @dev Returns true if swap and liquify feature is enabled.
*/
function swapAndLiquifyEnabled() external view returns (bool) {
return _swapAndLiquifyEnabled;
}
/**
* @dev Disables or enables the swap and liquify feature.
*/
function enableSwapAndLiquify(bool isEnabled) external onlyOwner {
_swapAndLiquifyEnabled = isEnabled;
emit SwapAndLiquifyEnabledUpdated(isEnabled);
}
/**
* @dev Updates the minimum amount of tokens before triggering Swap and Liquify
*/
function minTokensBeforeSwapAndLiquify() external view returns (uint256) {
return _minTokensBeforeSwapAndLiquify;
}
/**
* @dev Updates the minimum amount of tokens before triggering Swap and Liquify
*/
function setMinTokensBeforeSwapAndLiquify(uint256 minTokens) external onlyOwner {
require(minTokens < _totalSupply, "New value must be lower than total supply.");
_minTokensBeforeSwapAndLiquify = minTokens;
emit MinTokensBeforeSwapUpdated(minTokens);
}
/**
* @dev Returns the address of the liquidity wallet, or 0 if not using it.
*/
function liquidityWallet() external view returns (address) {
return _liquidityWallet;
}
/**
* @dev Sets the address of the liquidity wallet.
*/
function setLiquidityWallet(address newWallet) external onlyOwner {
_isExcludedFromFee[newWallet] = true;
_liquidityWallet = newWallet;
emit LiquidityWalletUpdated(newWallet);
}
/**
* @dev Returns true if dev fee is enabled.
*/
function devFeeEnabled() external view returns (bool) {
return _devFeeEnabled;
}
/**
* @dev Sets whether to collect or not the dev fee.
*/
function enableDevFee(bool isEnabled) external onlyOwner {
_devFeeEnabled = isEnabled;
emit DevFeeEnabledUpdated(isEnabled);
}
/**
* @dev Returns true if ops fee is enabled.
*/
function opsFeeEnabled() external view returns (bool) {
return _opsFeeEnabled;
}
/**
* @dev Sets whether to collect or not the ops fee.
*/
function enableOpsFee(bool isEnabled) external onlyOwner {
_opsFeeEnabled = isEnabled;
emit OpsFeeEnabledUpdated(isEnabled);
}
/**
* @dev Returns true if liquidity fee is enabled.
*/
function liquidityFeeEnabled() external view returns (bool) {
return _liquidityFeeEnabled;
}
/**
* @dev Sets whether to collect or not the liquidity fee.
*/
function enableLiquidityFee(bool isEnabled) external onlyOwner {
_liquidityFeeEnabled = isEnabled;
emit LiquidityFeeEnabledUpdated(isEnabled);
}
/**
* @dev Returns true if archa fee is enabled.
*/
function archaFeeEnabled() external view returns (bool) {
return _archaFeeEnabled;
}
/**
* @dev Sets whether to collect or not the archa fee.
*/
function enableArchaFee(bool isEnabled) external onlyOwner {
_archaFeeEnabled = isEnabled;
emit ArchaFeeEnabledUpdated(isEnabled);
}
/**
* @dev Returns true if the burn fee is enabled.
*/
function burnFeeEnabled() external view returns (bool) {
return _burnFeeEnabled;
}
/**
* @dev Sets whether to enable or not the burn fee.
*/
function enableBurnFee(bool isEnabled) external onlyOwner {
_burnFeeEnabled = isEnabled;
emit BurnFeeEnabledUpdated(isEnabled);
}
/**
* @dev Returns true if token stability protection is enabled.
*/
function tokenStabilityProtectionEnabled() external view returns (bool) {
return _tokenStabilityProtectionEnabled;
}
/**
* @dev Sets whether to enable the token stability protection.
*/
function enableTokenStabilityProtection(bool isEnabled) external onlyOwner {
_tokenStabilityProtectionEnabled = isEnabled;
emit TokenStabilityProtectionEnabledUpdated(isEnabled);
}
// Fees
/**
* @dev Returns the amount of the dev fee tokens pending swap
*/
function devFeePendingSwap() external onlyOwner view returns (uint256) {
return _devFeePendingSwap;
}
/**
* @dev Returns the amount of the ops fee tokens pending swap
*/
function opsFeePendingSwap() external onlyOwner view returns (uint256) {
return _opsFeePendingSwap;
}
/**
* @dev Returns the amount of the liquidity fee tokens pending swap
*/
function liquidityFeePendingSwap() external onlyOwner view returns (uint256) {
return _liquidityFeePendingSwap;
}
// Uniswap
function _initSwap(address routerAddress) private {
// Setup Uniswap router
_uniswapV2Router = IUniswapV2Router02(routerAddress);
// Get uniswap pair for this token or create if needed
address uniswapV2Pair_ = IUniswapV2Factory(_uniswapV2Router.factory())
.getPair(address(this), _uniswapV2Router.WETH());
if (uniswapV2Pair_ == address(0)) {
uniswapV2Pair_ = IUniswapV2Factory(_uniswapV2Router.factory())
.createPair(address(this), _uniswapV2Router.WETH());
}
_uniswapV2Pair = IUniswapV2Pair(uniswapV2Pair_);
// Exclude from fee
_isExcludedFromFee[address(_uniswapV2Router)] = true;
}
/**
* @dev Returns the address of the Token<>WETH pair.
*/
function uniswapV2Pair() external view returns (address) {
return address(_uniswapV2Pair);
}
/**
* @dev Swap `amount` tokens for ETH and send to `recipient`
*
* Emits {Transfer} event. From this contract to the token and WETH Pair.
*/
function _swapTokensForEth(uint256 amount, address recipient) private lockTheSwap {
// Generate the uniswap pair path of Token <> WETH
address[] memory path = new address[](2);
path[0] = address(this);
path[1] = _uniswapV2Router.WETH();
// Approve token transfer
_approve(address(this), address(_uniswapV2Router), amount);
// Make the swap
_uniswapV2Router.swapExactTokensForETHSupportingFeeOnTransferTokens(
amount,
0, // accept any amount of ETH
path,
recipient,
block.timestamp + _UNISWAP_DEADLINE_DELAY
);
}
/**
* @dev Add `ethAmount` of ETH and `tokenAmount` of tokens to the LP.
* Depends on the current rate for the pair between this token and WETH,
* `ethAmount` and `tokenAmount` might not match perfectly.
* Dust(leftover) ETH or token will be refunded to this contract
* (usually very small quantity).
*
*/
function _addLiquidity(uint256 ethAmount, uint256 tokenAmount) private {
// Approve token transfer
_approve(address(this), address(_uniswapV2Router), tokenAmount);
// Add the ETH<>Token pair to the pool.
_uniswapV2Router.addLiquidityETH {value: ethAmount} (
address(this),
tokenAmount,
0, // amountTokenMin
0, // amountETHMin
_lpTokensWallet, // the receiver of the lp tokens
block.timestamp + _UNISWAP_DEADLINE_DELAY
);
}
// Swap and liquify
/**
* @dev Swap half of the amount token balance for ETH,
* and pair it up with the other half to add to the
* liquidity pool.
*
* Emits {SwapAndLiquify} event indicating the amount of tokens swapped to eth,
* the amount of ETH added to the LP, and the amount of tokens added to the LP.
*/
function _swapAndLiquify(uint256 amount) private {
require(_swapAndLiquifyEnabled, "Swap And Liquify is disabled");
// Split the contract balance into two halves.
uint256 tokensToSwap = amount / 2;
uint256 tokensAddToLiquidity = amount - tokensToSwap;
// Contract's current ETH balance.
uint256 initialBalance = address(this).balance;
// Swap half of the tokens to ETH.
_swapTokensForEth(tokensToSwap, address(this));
// Figure out the exact amount of tokens received from swapping.
uint256 ethAddToLiquify = address(this).balance - initialBalance;
// Add to the LP of this token and WETH pair (half ETH and half this token).
_addLiquidity(ethAddToLiquify, tokensAddToLiquidity);
emit SwapAndLiquify(tokensToSwap, ethAddToLiquify, tokensAddToLiquidity);
}
function getTokenReserves() public view returns (uint256) {
uint112 reserve;
if (_uniswapV2Pair.token0() == address(this))
(reserve,,) = _uniswapV2Pair.getReserves();
else
(,reserve,) = _uniswapV2Pair.getReserves();
return uint256(reserve);
}
// Transfer
/**
* @dev Moves `amount` of tokens from `sender` to `recipient`.
*
* This internal function is equivalent to {transfer}, and can be used to
* e.g. implement automatic token fees, slashing mechanisms, etc.
*
* Emits a {Transfer} event.
*
* Requirements:
*
* - `sender` cannot be the zero address.
* - `recipient` cannot be the zero address.
* - `sender` must have a balance of at least `amount`.
*/
function _transfer(
address sender,
address recipient,
uint256 amount
) private {
require(sender != address(0), "ERC20: transfer from the zero address");
require(recipient != address(0), "ERC20: transfer to the zero address");
require(amount > 0, "ScratchToken: Transfer amount must be greater than zero");
require(_balances[sender] >= amount, "ERC20: transfer amount exceeds balance");
// Indicates if fee should be deducted from transfer
bool selling = recipient == address(_uniswapV2Pair);
bool buying = sender == address(_uniswapV2Pair) && recipient != address(_uniswapV2Router);
// Take fees when selling or buying, and the sender and recipient are not excluded
bool takeFee = (selling || buying) && (!_isExcludedFromFee[sender] && !_isExcludedFromFee[recipient]);
// Transfer amount, it will take fees if takeFee is true
_tokenTransfer(sender, recipient, amount, takeFee, buying);
}
function _tokenTransfer(address sender, address recipient, uint256 amount, bool takeFee, bool buying) private {
uint256 amountMinusFees = amount;
if (takeFee) {
// Maybe trigger token stability protection
uint256 extraLiquidityFee = 0;
uint256 extraDevFee = 0;
uint256 extraBurnFee = 0;
if (!buying && _tokenStabilityProtectionEnabled && amount >= (getTokenReserves() * _TOKEN_STABILITY_PROTECTION_THRESHOLD_PERCENTAGE / _PERCENTAGE_RELATIVE_TO)) {
// Liquidity fee
extraLiquidityFee = amount * _TAX_EXTRA_LIQUIDITY_PERCENTAGE / _PERCENTAGE_RELATIVE_TO;
// Dev fee
extraDevFee = amount * _TAX_EXTRA_DEV_PERCENTAGE / _PERCENTAGE_RELATIVE_TO;
// Burn
extraBurnFee = amount * _TAX_EXTRA_BURN_PERCENTAGE / _PERCENTAGE_RELATIVE_TO;
}
// Archa
uint256 archaFee = 0;
if (_archaFeeEnabled) {
archaFee = amount * _TAX_NORMAL_ARCHA_PERCENTAGE / _PERCENTAGE_RELATIVE_TO;
if (archaFee > 0) {
_balances[_archaWallet] += archaFee;
emit Transfer(sender, _archaWallet, archaFee);
}
}
// Dev fee
uint256 devFee = 0;
if (_devFeeEnabled) {
devFee = (amount * _TAX_NORMAL_DEV_PERCENTAGE / _PERCENTAGE_RELATIVE_TO) + extraDevFee;
if (devFee > 0) {
_balances[address(this)] += devFee;
if (buying || _inSwap) {
// Store for a later swap
_devFeePendingSwap += devFee;
}
else {
// Swap for eth
_swapTokensForEth(devFee + _devFeePendingSwap, _developmentWallet);
emit Transfer(sender, _developmentWallet, devFee + _devFeePendingSwap);
_devFeePendingSwap = 0;
}
}
}
// Ops
uint256 opsFee = 0;
if (_opsFeeEnabled) {
opsFee = amount * _TAX_NORMAL_OPS_PERCENTAGE / _PERCENTAGE_RELATIVE_TO;
if (opsFee > 0) {
_balances[address(this)] += opsFee;
if (buying || _inSwap) {
// Store for a later swap
_opsFeePendingSwap += opsFee;
}
else {
// Swap for eth
_swapTokensForEth(opsFee + _opsFeePendingSwap, _operationsWallet);
emit Transfer(sender, _operationsWallet, opsFee + _opsFeePendingSwap);
_opsFeePendingSwap = 0;
}
}
}
// Liquity pool
uint256 liquidityFee = 0;
if (_liquidityFeeEnabled) {
liquidityFee = (amount * _TAX_NORMAL_LIQUIDITY_PERCENTAGE / _PERCENTAGE_RELATIVE_TO) + extraLiquidityFee;
if (liquidityFee > 0) {
_balances[address(this)] += liquidityFee;
if (buying || _inSwap) {
// Store for a later swap
_liquidityFeePendingSwap += liquidityFee;
}
else {
uint256 swapAndLiquifyAmount = liquidityFee + _liquidityFeePendingSwap;
if(_swapAndLiquifyEnabled) {
// Swap and liquify
if(swapAndLiquifyAmount > _minTokensBeforeSwapAndLiquify) {
_swapAndLiquify(swapAndLiquifyAmount);
_liquidityFeePendingSwap = 0;
} else {
// Accumulate until minimum amount is reached
_liquidityFeePendingSwap += liquidityFee;
}
} else if (_liquidityWallet != address(0)) {
// Send to liquidity wallet
_swapTokensForEth(swapAndLiquifyAmount, _liquidityWallet);
emit Transfer(sender, _liquidityWallet, swapAndLiquifyAmount);
_liquidityFeePendingSwap = 0;
} else {
// Keep for later
_liquidityFeePendingSwap += liquidityFee;
}
}
}
}
// Burn
uint256 burnFee = 0;
if(_burnFeeEnabled && extraBurnFee > 0) {
burnFee = extraBurnFee;
_totalSupply -= burnFee;
emit Transfer(sender, address(0), amount);
}
// Final transfer amount
uint256 totalFees = devFee + liquidityFee + opsFee + archaFee + burnFee;
require (amount > totalFees, "ScratchToken: Token fees exceeds transfer amount");
amountMinusFees = amount - totalFees;
} else {
amountMinusFees = amount;
}
_balances[sender] -= amount;
_balances[recipient] += amountMinusFees;
emit Transfer(sender, recipient, amountMinusFees);
}
// ERC20
/**
* @dev Returns the name of the token.
*/
function name() external view virtual returns (string memory) {
return _NAME;
}
/**
* @dev Returns the symbol of the token, usually a shorter version of the
* name.
*/
function symbol() external view virtual returns (string memory) {
return _SYMBOL;
}
/**
* @dev Returns the number of decimals used to get its user representation.
* For example, if `decimals` equals `2`, a balance of `505` tokens in the contract
* should be displayed to a user as `5.05` (`505 / 10 ** 2`).
*
* NOTE: This information is only used for _display_ purposes: it in
* no way affects any of the arithmetic of the contract, including
* {IERC20-balanceOf} and {IERC20-transfer}.
*/
function decimals() external view returns (uint8) {
return _DECIMALS;
}
/**
* @dev See {IERC20-totalSupply}.
*/
function totalSupply() public view virtual override returns (uint256) {
return _totalSupply;
}
/**
* @dev See {IERC20-balanceOf}.
*/
function balanceOf(address account) external view virtual override returns (uint256) {
return _balances[account];
}
/**
* @dev Max supply of the token, cannot be increased after deployment.
*/
function maxSupply() external view returns (uint256) {
return _MAX_SUPPLY;
}
// Transfer
/**
* @dev See {IERC20-transfer}.
*
* Requirements:
*
* - `recipient` cannot be the zero address.
* - the caller must have a balance of at least `amount`.
*/
function transfer(address recipient, uint256 amount) external override returns (bool) {
_transfer(_msgSender(), recipient, amount);
return true;
}
/**
* @dev See {IERC20-transferFrom}.
*
* Emits an {Approval} event indicating the updated allowance. This is not
* required by the EIP. See the note at the beginning of {ERC20}.
*
* Requirements:
*
* - `sender` and `recipient` cannot be the zero address.
* - `sender` must have a balance of at least `amount`.
* - the caller must have allowance for ``sender``'s tokens of at least
* `amount`.
*/
function transferFrom(
address sender,
address recipient,
uint256 amount
) external virtual override returns (bool) {
_transfer(sender, recipient, amount);
uint256 currentAllowance = _allowances[sender][_msgSender()];
require(currentAllowance >= amount, "ERC20: transfer amount exceeds allowance");
unchecked {
_approve(sender, _msgSender(), currentAllowance - amount);
}
return true;
}
// Allowance
/**
* @dev See {IERC20-approve}.
*
* Requirements:
*
* - `spender` cannot be the zero address.
*/
function approve(address spender, uint256 amount) external virtual override returns (bool) {
_approve(_msgSender(), spender, amount);
return true;
}
/**
* @dev See {IERC20-allowance}.
*/
function allowance(address owner, address spender) external view virtual override returns (uint256) {
return _allowances[owner][spender];
}
/**
* @dev Atomically increases the allowance granted to `spender` by the caller.
*
* This is an alternative to {approve} that can be used as a mitigation for
* problems described in {IERC20-approve}.
*
* Emits an {Approval} event indicating the updated allowance.
*
* Requirements:
*
* - `spender` cannot be the zero address.
*/
function increaseAllowance(address spender, uint256 addedValue) external virtual returns (bool) {
_approve(_msgSender(), spender, _allowances[_msgSender()][spender] + addedValue);
return true;
}
/**
* @dev Atomically decreases the allowance granted to `spender` by the caller.
*
* This is an alternative to {approve} that can be used as a mitigation for
* problems described in {IERC20-approve}.
*
* Emits an {Approval} event indicating the updated allowance.
*
* Requirements:
*
* - `spender` cannot be the zero address.
* - `spender` must have allowance for the caller of at least
* `subtractedValue`.
*/
function decreaseAllowance(address spender, uint256 subtractedValue) external virtual returns (bool) {
uint256 currentAllowance = _allowances[_msgSender()][spender];
require(currentAllowance >= subtractedValue, "ERC20: decreased allowance below zero");
unchecked {
_approve(_msgSender(), spender, currentAllowance - subtractedValue);
}
return true;
}
/**
* @dev Sets `amount` as the allowance of `spender` over the `owner` s tokens.
*
* This internal function is equivalent to `approve`, and can be used to
* e.g. set automatic allowances for certain subsystems, etc.
*
* Emits an {Approval} event.
*
* Requirements:
*
* - `owner` cannot be the zero address.
* - `spender` cannot be the zero address.
*/
function _approve(
address owner,
address spender,
uint256 amount
) internal {
require(owner != address(0), "ERC20: approve from the zero address");
require(spender != address(0), "ERC20: approve to the zero address");
_allowances[owner][spender] = amount;
emit Approval(owner, spender, amount);
}
// Mint & Burn
/** @dev Creates `amount` tokens and assigns them to `account`, increasing
* the total supply.
*
* Emits a {Transfer} event with `from` set to the zero address.
*
* Requirements:
*
* - `account` cannot be the zero address.
*/
function _mint(address account, uint256 amount) internal {
require(account != address(0), "ERC20: mint to the zero address");
_totalSupply += amount;
_balances[account] += amount;
emit Transfer(address(0), account, amount);
}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/ERC20Burnable.sol)
pragma solidity ^0.8.0;
import "../ERC20.sol";
import "../../../utils/Context.sol";
/**
* @dev Extension of {ERC20} that allows token holders to destroy both their own
* tokens and those that they have an allowance for, in a way that can be
* recognized off-chain (via event analysis).
*/
abstract contract ERC20Burnable is Context, ERC20 {
/**
* @dev Destroys `amount` tokens from the caller.
*
* See {ERC20-_burn}.
*/
function burn(uint256 amount) public virtual {
_burn(_msgSender(), amount);
}
/**
* @dev Destroys `amount` tokens from `account`, deducting from the caller's
* allowance.
*
* See {ERC20-_burn} and {ERC20-allowance}.
*
* Requirements:
*
* - the caller must have allowance for ``accounts``'s tokens of at least
* `amount`.
*/
function burnFrom(address account, uint256 amount) public virtual {
uint256 currentAllowance = allowance(account, _msgSender());
require(currentAllowance >= amount, "ERC20: burn amount exceeds allowance");
unchecked {
_approve(account, _msgSender(), currentAllowance - amount);
}
_burn(account, amount);
}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (access/Ownable.sol)
pragma solidity ^0.8.0;
import "../utils/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() {
_transferOwnership(_msgSender());
}
/**
* @dev Returns the address of the current owner.
*/
function owner() public view virtual 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 {
_transferOwnership(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");
_transferOwnership(newOwner);
}
/**
* @dev Transfers ownership of the contract to a new account (`newOwner`).
* Internal function without access restriction.
*/
function _transferOwnership(address newOwner) internal virtual {
address oldOwner = _owner;
_owner = newOwner;
emit OwnershipTransferred(oldOwner, newOwner);
}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Address.sol)
pragma solidity ^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;
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");
(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");
(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");
(bool success, bytes memory returndata) = target.staticcall(data);
return verifyCallResult(success, returndata, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but performing a delegate call.
*
* _Available since v3.4._
*/
function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
return functionDelegateCall(target, data, "Address: low-level delegate call failed");
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
* but performing a delegate call.
*
* _Available since v3.4._
*/
function functionDelegateCall(
address target,
bytes memory data,
string memory errorMessage
) internal returns (bytes memory) {
require(isContract(target), "Address: delegate call to non-contract");
(bool success, bytes memory returndata) = target.delegatecall(data);
return verifyCallResult(success, returndata, errorMessage);
}
/**
* @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
* revert reason using the provided one.
*
* _Available since v4.3._
*/
function verifyCallResult(
bool success,
bytes memory returndata,
string memory errorMessage
) internal 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
assembly {
let returndata_size := mload(returndata)
revert(add(32, returndata), returndata_size)
}
} else {
revert(errorMessage);
}
}
}
}
pragma solidity >=0.5.0;
interface IUniswapV2Pair {
event Approval(address indexed owner, address indexed spender, uint value);
event Transfer(address indexed from, address indexed to, uint value);
function name() external pure returns (string memory);
function symbol() external pure returns (string memory);
function decimals() external pure returns (uint8);
function totalSupply() external view returns (uint);
function balanceOf(address owner) external view returns (uint);
function allowance(address owner, address spender) external view returns (uint);
function approve(address spender, uint value) external returns (bool);
function transfer(address to, uint value) external returns (bool);
function transferFrom(address from, address to, uint value) external returns (bool);
function DOMAIN_SEPARATOR() external view returns (bytes32);
function PERMIT_TYPEHASH() external pure returns (bytes32);
function nonces(address owner) external view returns (uint);
function permit(address owner, address spender, uint value, uint deadline, uint8 v, bytes32 r, bytes32 s) external;
event Mint(address indexed sender, uint amount0, uint amount1);
event Burn(address indexed sender, uint amount0, uint amount1, address indexed to);
event Swap(
address indexed sender,
uint amount0In,
uint amount1In,
uint amount0Out,
uint amount1Out,
address indexed to
);
event Sync(uint112 reserve0, uint112 reserve1);
function MINIMUM_LIQUIDITY() external pure returns (uint);
function factory() external view returns (address);
function token0() external view returns (address);
function token1() external view returns (address);
function getReserves() external view returns (uint112 reserve0, uint112 reserve1, uint32 blockTimestampLast);
function price0CumulativeLast() external view returns (uint);
function price1CumulativeLast() external view returns (uint);
function kLast() external view returns (uint);
function mint(address to) external returns (uint liquidity);
function burn(address to) external returns (uint amount0, uint amount1);
function swap(uint amount0Out, uint amount1Out, address to, bytes calldata data) external;
function skim(address to) external;
function sync() external;
function initialize(address, address) external;
}
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;
}
pragma solidity >=0.6.2;
import './IUniswapV2Router01.sol';
interface IUniswapV2Router02 is IUniswapV2Router01 {
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: UNLICENSED
/**
* Copyright © 2022 Scratch Engine LLC. All rights reserved.
* Limited license is afforded to Etherscan, in accordance with its Terms of Use,
* in order to publish this material.
* In connection with the foregoing, redistribution and use on the part of Etherscan,
* in source and binary forms, without modification, are permitted,
* provided that such redistributions of source code retain the foregoing copyright notice
* and this disclaimer.
*/
pragma solidity 0.8.4;
// import "hardhat/console.sol";
import "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/utils/math/SafeMath.sol";
/**
* @title FoundersTimelock
* @dev A token holder contract that can release its token balance gradually like a
* typical vesting scheme, with a cliff and vesting period.
*/
contract FoundersTimelock is Ownable {
// The vesting schedule is time-based (i.e. using block timestamps as opposed to e.g. block numbers), and is
// therefore sensitive to timestamp manipulation (which is something miners can do, to a certain degree). Therefore,
// it is recommended to avoid using short time durations (less than a minute). Typical vesting schemes, with a
// cliff period of a year and a duration of four years, are safe to use.
using SafeMath for uint256;
using SafeERC20 for IERC20;
event TokensReleased(address token, uint256 amount);
// beneficiary of tokens after they are released
address private immutable _beneficiary;
// ERC20 basic token contract being held
IERC20 private immutable _token;
uint256 private immutable _cliff; // cliff period in seconds
uint256 private immutable _vestingPeriod; // ie: 1 month
uint8 private immutable _vestingDuration; // ie: 10 (vesting will last for 10 months and release linearly every month)
uint256 private _released = 0;
/**
* @dev Creates a vesting contract that vests its balance of any ERC20 token to the
* beneficiary, gradually in a linear fashion until start + duration. By then all
* of the balance will have vested.
* @param token_ ERC20 basic token contract being held
* @param beneficiary_ address of the beneficiary to whom vested tokens are transferred
* @param cliffDuration_ duration in seconds of the cliff in which tokens will begin to vest
* @param vestingPeriod_ the frequency (as Unix time) at which tokens are released
* @param vestingDuration_ the total count of vesting periods
*/
constructor (IERC20 token_, address beneficiary_, uint256 cliffDuration_, uint256 vestingPeriod_, uint8 vestingDuration_) {
require(beneficiary_ != address(0), "FoundersTimelock: beneficiary is the zero address");
require(vestingPeriod_ > 0, "FoundersTimelock: vestingPeriod is 0");
require(vestingDuration_ > 0, "FoundersTimelock: vestingDuration is 0");
require(vestingDuration_ < 256, "FoundersTimelock: vestingDuration is bigger than 255");
_token = token_;
_beneficiary = beneficiary_;
// solhint-disable-next-line not-rely-on-time
_cliff = block.timestamp.add(cliffDuration_); // safe the use with the 15-seconds rule
_vestingPeriod = vestingPeriod_;
_vestingDuration = vestingDuration_;
}
/**
* @return the beneficiary of the tokens.
*/
function beneficiary() external view returns (address) {
return _beneficiary;
}
/**
* @return the cliff time of the token vesting.
*/
function cliff() external view returns (uint256) {
return _cliff;
}
/**
* @return the vesting frequency of the token vesting.
*/
function vestingPeriod() external view returns (uint256) {
return _vestingPeriod;
}
/**
* @return the duration of the token vesting.
*/
function vestingDuration() external view returns (uint256) {
return _vestingDuration;
}
/**
* @return the amount of tokens released.
*/
function releasedBalance() external view returns (uint256) {
return _released;
}
/**
* @return the amount of tokens still locked
*/
function lockedBalance() external view returns (uint256) {
return _token.balanceOf(address(this));
}
/**
* @notice Transfers vested tokens to beneficiary.
*/
function release() external {
require (msg.sender == _beneficiary, "FoundersTimelock: only beneficiary can release tokens");
uint256 unreleased = _releasableAmount();
require(unreleased > 0, "FoundersTimelock: no tokens are due");
_released = _released + unreleased;
_token.safeTransfer(_beneficiary, unreleased);
emit TokensReleased(address(_token), unreleased);
}
/**
* @dev Calculates the amount that has already vested but hasn't been released yet.
*/
function _releasableAmount() private view returns (uint256) {
return _vestedAmount().sub(_released);
}
/**
* @dev Calculates the amount that has already vested.
*/
function _vestedAmount() private view returns (uint256) {
uint256 currentBalance = _token.balanceOf(address(this));
uint256 totalBalance = currentBalance.add(_released);
if (block.timestamp < _cliff) {
return 0;
} else if (block.timestamp >= _cliff.add(_vestingDuration * _vestingPeriod)) { // solhint-disable-line not-rely-on-time
return totalBalance;
} else {
// Vesting period
uint256 vestingElapsed = block.timestamp.sub(_cliff);
uint256 vestingStep = (vestingElapsed / _vestingPeriod) + 1; // Round up
if(vestingStep > _vestingDuration) {
vestingStep = _vestingDuration;
}
return totalBalance.mul(vestingStep).div(_vestingDuration);
}
}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/ERC20.sol)
pragma solidity ^0.8.0;
import "./IERC20.sol";
import "./extensions/IERC20Metadata.sol";
import "../../utils/Context.sol";
/**
* @dev Implementation of the {IERC20} interface.
*
* This implementation is agnostic to the way tokens are created. This means
* that a supply mechanism has to be added in a derived contract using {_mint}.
* For a generic mechanism see {ERC20PresetMinterPauser}.
*
* TIP: For a detailed writeup see our guide
* https://forum.zeppelin.solutions/t/how-to-implement-erc20-supply-mechanisms/226[How
* to implement supply mechanisms].
*
* We have followed general OpenZeppelin Contracts guidelines: functions revert
* instead returning `false` on failure. This behavior is nonetheless
* conventional and does not conflict with the expectations of ERC20
* applications.
*
* Additionally, an {Approval} event is emitted on calls to {transferFrom}.
* This allows applications to reconstruct the allowance for all accounts just
* by listening to said events. Other implementations of the EIP may not emit
* these events, as it isn't required by the specification.
*
* Finally, the non-standard {decreaseAllowance} and {increaseAllowance}
* functions have been added to mitigate the well-known issues around setting
* allowances. See {IERC20-approve}.
*/
contract ERC20 is Context, IERC20, IERC20Metadata {
mapping(address => uint256) private _balances;
mapping(address => mapping(address => uint256)) private _allowances;
uint256 private _totalSupply;
string private _name;
string private _symbol;
/**
* @dev Sets the values for {name} and {symbol}.
*
* The default value of {decimals} is 18. To select a different value for
* {decimals} you should overload it.
*
* All two of these values are immutable: they can only be set once during
* construction.
*/
constructor(string memory name_, string memory symbol_) {
_name = name_;
_symbol = symbol_;
}
/**
* @dev Returns the name of the token.
*/
function name() public view virtual override returns (string memory) {
return _name;
}
/**
* @dev Returns the symbol of the token, usually a shorter version of the
* name.
*/
function symbol() public view virtual override returns (string memory) {
return _symbol;
}
/**
* @dev Returns the number of decimals used to get its user representation.
* For example, if `decimals` equals `2`, a balance of `505` tokens should
* be displayed to a user as `5.05` (`505 / 10 ** 2`).
*
* Tokens usually opt for a value of 18, imitating the relationship between
* Ether and Wei. This is the value {ERC20} uses, unless this function is
* overridden;
*
* NOTE: This information is only used for _display_ purposes: it in
* no way affects any of the arithmetic of the contract, including
* {IERC20-balanceOf} and {IERC20-transfer}.
*/
function decimals() public view virtual override returns (uint8) {
return 18;
}
/**
* @dev See {IERC20-totalSupply}.
*/
function totalSupply() public view virtual override returns (uint256) {
return _totalSupply;
}
/**
* @dev See {IERC20-balanceOf}.
*/
function balanceOf(address account) public view virtual override returns (uint256) {
return _balances[account];
}
/**
* @dev See {IERC20-transfer}.
*
* Requirements:
*
* - `recipient` cannot be the zero address.
* - the caller must have a balance of at least `amount`.
*/
function transfer(address recipient, uint256 amount) public virtual override returns (bool) {
_transfer(_msgSender(), recipient, amount);
return true;
}
/**
* @dev See {IERC20-allowance}.
*/
function allowance(address owner, address spender) public view virtual override returns (uint256) {
return _allowances[owner][spender];
}
/**
* @dev See {IERC20-approve}.
*
* Requirements:
*
* - `spender` cannot be the zero address.
*/
function approve(address spender, uint256 amount) public virtual override returns (bool) {
_approve(_msgSender(), spender, amount);
return true;
}
/**
* @dev See {IERC20-transferFrom}.
*
* Emits an {Approval} event indicating the updated allowance. This is not
* required by the EIP. See the note at the beginning of {ERC20}.
*
* Requirements:
*
* - `sender` and `recipient` cannot be the zero address.
* - `sender` must have a balance of at least `amount`.
* - the caller must have allowance for ``sender``'s tokens of at least
* `amount`.
*/
function transferFrom(
address sender,
address recipient,
uint256 amount
) public virtual override returns (bool) {
_transfer(sender, recipient, amount);
uint256 currentAllowance = _allowances[sender][_msgSender()];
require(currentAllowance >= amount, "ERC20: transfer amount exceeds allowance");
unchecked {
_approve(sender, _msgSender(), currentAllowance - amount);
}
return true;
}
/**
* @dev Atomically increases the allowance granted to `spender` by the caller.
*
* This is an alternative to {approve} that can be used as a mitigation for
* problems described in {IERC20-approve}.
*
* Emits an {Approval} event indicating the updated allowance.
*
* Requirements:
*
* - `spender` cannot be the zero address.
*/
function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
_approve(_msgSender(), spender, _allowances[_msgSender()][spender] + addedValue);
return true;
}
/**
* @dev Atomically decreases the allowance granted to `spender` by the caller.
*
* This is an alternative to {approve} that can be used as a mitigation for
* problems described in {IERC20-approve}.
*
* Emits an {Approval} event indicating the updated allowance.
*
* Requirements:
*
* - `spender` cannot be the zero address.
* - `spender` must have allowance for the caller of at least
* `subtractedValue`.
*/
function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {
uint256 currentAllowance = _allowances[_msgSender()][spender];
require(currentAllowance >= subtractedValue, "ERC20: decreased allowance below zero");
unchecked {
_approve(_msgSender(), spender, currentAllowance - subtractedValue);
}
return true;
}
/**
* @dev Moves `amount` of tokens from `sender` to `recipient`.
*
* This internal function is equivalent to {transfer}, and can be used to
* e.g. implement automatic token fees, slashing mechanisms, etc.
*
* Emits a {Transfer} event.
*
* Requirements:
*
* - `sender` cannot be the zero address.
* - `recipient` cannot be the zero address.
* - `sender` must have a balance of at least `amount`.
*/
function _transfer(
address sender,
address recipient,
uint256 amount
) internal virtual {
require(sender != address(0), "ERC20: transfer from the zero address");
require(recipient != address(0), "ERC20: transfer to the zero address");
_beforeTokenTransfer(sender, recipient, amount);
uint256 senderBalance = _balances[sender];
require(senderBalance >= amount, "ERC20: transfer amount exceeds balance");
unchecked {
_balances[sender] = senderBalance - amount;
}
_balances[recipient] += amount;
emit Transfer(sender, recipient, amount);
_afterTokenTransfer(sender, recipient, amount);
}
/** @dev Creates `amount` tokens and assigns them to `account`, increasing
* the total supply.
*
* Emits a {Transfer} event with `from` set to the zero address.
*
* Requirements:
*
* - `account` cannot be the zero address.
*/
function _mint(address account, uint256 amount) internal virtual {
require(account != address(0), "ERC20: mint to the zero address");
_beforeTokenTransfer(address(0), account, amount);
_totalSupply += amount;
_balances[account] += amount;
emit Transfer(address(0), account, amount);
_afterTokenTransfer(address(0), account, amount);
}
/**
* @dev Destroys `amount` tokens from `account`, reducing the
* total supply.
*
* Emits a {Transfer} event with `to` set to the zero address.
*
* Requirements:
*
* - `account` cannot be the zero address.
* - `account` must have at least `amount` tokens.
*/
function _burn(address account, uint256 amount) internal virtual {
require(account != address(0), "ERC20: burn from the zero address");
_beforeTokenTransfer(account, address(0), amount);
uint256 accountBalance = _balances[account];
require(accountBalance >= amount, "ERC20: burn amount exceeds balance");
unchecked {
_balances[account] = accountBalance - amount;
}
_totalSupply -= amount;
emit Transfer(account, address(0), amount);
_afterTokenTransfer(account, address(0), amount);
}
/**
* @dev Sets `amount` as the allowance of `spender` over the `owner` s tokens.
*
* This internal function is equivalent to `approve`, and can be used to
* e.g. set automatic allowances for certain subsystems, etc.
*
* Emits an {Approval} event.
*
* Requirements:
*
* - `owner` cannot be the zero address.
* - `spender` cannot be the zero address.
*/
function _approve(
address owner,
address spender,
uint256 amount
) internal virtual {
require(owner != address(0), "ERC20: approve from the zero address");
require(spender != address(0), "ERC20: approve to the zero address");
_allowances[owner][spender] = amount;
emit Approval(owner, spender, amount);
}
/**
* @dev Hook that is called before any transfer of tokens. This includes
* minting and burning.
*
* Calling conditions:
*
* - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
* will be transferred to `to`.
* - when `from` is zero, `amount` tokens will be minted for `to`.
* - when `to` is zero, `amount` of ``from``'s tokens will be burned.
* - `from` and `to` are never both zero.
*
* To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
*/
function _beforeTokenTransfer(
address from,
address to,
uint256 amount
) internal virtual {}
/**
* @dev Hook that is called after any transfer of tokens. This includes
* minting and burning.
*
* Calling conditions:
*
* - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
* has been transferred to `to`.
* - when `from` is zero, `amount` tokens have been minted for `to`.
* - when `to` is zero, `amount` of ``from``'s tokens have been burned.
* - `from` and `to` are never both zero.
*
* To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
*/
function _afterTokenTransfer(
address from,
address to,
uint256 amount
) internal virtual {}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)
pragma solidity ^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 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) {
return msg.sender;
}
function _msgData() internal view virtual returns (bytes calldata) {
return msg.data;
}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/IERC20.sol)
pragma solidity ^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
// OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/IERC20Metadata.sol)
pragma solidity ^0.8.0;
import "../IERC20.sol";
/**
* @dev Interface for the optional metadata functions from the ERC20 standard.
*
* _Available since v4.1._
*/
interface IERC20Metadata is IERC20 {
/**
* @dev Returns the name of the token.
*/
function name() external view returns (string memory);
/**
* @dev Returns the symbol of the token.
*/
function symbol() external view returns (string memory);
/**
* @dev Returns the decimals places of the token.
*/
function decimals() external view returns (uint8);
}
pragma solidity >=0.6.2;
interface IUniswapV2Router01 {
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);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/utils/SafeERC20.sol)
pragma solidity ^0.8.0;
import "../IERC20.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 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'
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) + value;
_callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
}
function safeDecreaseAllowance(
IERC20 token,
address spender,
uint256 value
) internal {
unchecked {
uint256 oldAllowance = token.allowance(address(this), spender);
require(oldAllowance >= value, "SafeERC20: decreased allowance below zero");
uint256 newAllowance = oldAllowance - value;
_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
require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
}
}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/math/SafeMath.sol)
pragma solidity ^0.8.0;
// CAUTION
// This version of SafeMath should only be used with Solidity 0.8 or later,
// because it relies on the compiler's built in overflow checks.
/**
* @dev Wrappers over Solidity's arithmetic operations.
*
* NOTE: `SafeMath` is generally not needed starting with Solidity 0.8, since the compiler
* now has built in overflow checking.
*/
library SafeMath {
/**
* @dev Returns the addition of two unsigned integers, with an overflow flag.
*
* _Available since v3.4._
*/
function tryAdd(uint256 a, uint256 b) internal pure returns (bool, uint256) {
unchecked {
uint256 c = a + b;
if (c < a) return (false, 0);
return (true, c);
}
}
/**
* @dev Returns the substraction of two unsigned integers, with an overflow flag.
*
* _Available since v3.4._
*/
function trySub(uint256 a, uint256 b) internal pure returns (bool, uint256) {
unchecked {
if (b > a) return (false, 0);
return (true, a - b);
}
}
/**
* @dev Returns the multiplication of two unsigned integers, with an overflow flag.
*
* _Available since v3.4._
*/
function tryMul(uint256 a, uint256 b) internal pure returns (bool, uint256) {
unchecked {
// 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 (true, 0);
uint256 c = a * b;
if (c / a != b) return (false, 0);
return (true, c);
}
}
/**
* @dev Returns the division of two unsigned integers, with a division by zero flag.
*
* _Available since v3.4._
*/
function tryDiv(uint256 a, uint256 b) internal pure returns (bool, uint256) {
unchecked {
if (b == 0) return (false, 0);
return (true, a / b);
}
}
/**
* @dev Returns the remainder of dividing two unsigned integers, with a division by zero flag.
*
* _Available since v3.4._
*/
function tryMod(uint256 a, uint256 b) internal pure returns (bool, uint256) {
unchecked {
if (b == 0) return (false, 0);
return (true, a % b);
}
}
/**
* @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) {
return a + b;
}
/**
* @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 a - b;
}
/**
* @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) {
return a * b;
}
/**
* @dev Returns the integer division of two unsigned integers, reverting on
* division by zero. The result is rounded towards zero.
*
* Counterpart to Solidity's `/` operator.
*
* Requirements:
*
* - The divisor cannot be zero.
*/
function div(uint256 a, uint256 b) internal pure returns (uint256) {
return a / b;
}
/**
* @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
* reverting 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 a % b;
}
/**
* @dev Returns the subtraction of two unsigned integers, reverting with custom message on
* overflow (when the result is negative).
*
* CAUTION: This function is deprecated because it requires allocating memory for the error
* message unnecessarily. For custom revert reasons use {trySub}.
*
* Counterpart to Solidity's `-` operator.
*
* Requirements:
*
* - Subtraction cannot overflow.
*/
function sub(
uint256 a,
uint256 b,
string memory errorMessage
) internal pure returns (uint256) {
unchecked {
require(b <= a, errorMessage);
return a - b;
}
}
/**
* @dev Returns the integer division of two unsigned integers, reverting 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) {
unchecked {
require(b > 0, errorMessage);
return a / b;
}
}
/**
* @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
* reverting with custom message when dividing by zero.
*
* CAUTION: This function is deprecated because it requires allocating memory for the error
* message unnecessarily. For custom revert reasons use {tryMod}.
*
* 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) {
unchecked {
require(b > 0, errorMessage);
return a % b;
}
}
}