Contract Source Code:
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.12;
import {Ownable} from "openzeppelin/access/Ownable.sol";
import {ERC20} from "openzeppelin/token/ERC20/ERC20.sol";
import {IERC20} from "openzeppelin/token/ERC20/IERC20.sol";
import {SafeMath} from "openzeppelin/utils/math/SafeMath.sol";
import {IUniswapV2Factory} from "./interfaces/IUniswapV2Factory.sol";
import {IUniswapV2Router02} from "./interfaces/IUniswapV2Router02.sol";
contract FAC is ERC20, Ownable {
using SafeMath for uint256;
IUniswapV2Router02 public immutable uniswapRouter;
address public uniswapV2Pair;
bool private swapping;
address public treasuryWallet;
uint256 public maxTransactionAmount;
uint256 public swapTokensAtAmount;
uint256 public maxWallet;
bool public limitsInEffect = true;
bool public tradingActive = false;
bool public swapEnabled = false;
bool public blacklistRenounced = false;
// Anti-bot and anti-whale mappings and variables
mapping(address => bool) blacklisted;
uint256 public buyTotalFees;
uint256 public buyTreasuryFee;
uint256 public sellTotalFees;
uint256 public sellTreasuryFee;
uint256 public tokensForTreasury;
/******************/
// exclude from fees and max transaction amount
mapping(address => bool) private _isExcludedFromFees;
mapping(address => bool) public _isExcludedMaxTransactionAmount;
// store addresses that a automatic market maker pairs. Any transfer *to* these addresses
// could be subject to a maximum transfer amount
mapping(address => bool) public automatedMarketMakerPairs;
event UpdateUniswapRouter(
address indexed newAddress,
address indexed oldAddress
);
event ExcludeFromFees(address indexed account, bool isExcluded);
event SetAutomatedMarketMakerPair(address indexed pair, bool indexed value);
event treasuryWalletUpdated(
address indexed newWallet,
address indexed oldWallet
);
constructor() ERC20("FacTAO", "FAC") {
IUniswapV2Router02 _uniswapRouter = IUniswapV2Router02(
0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D
);
excludeFromMaxTransaction(address(_uniswapRouter), true);
uniswapRouter = _uniswapRouter;
uint256 _buyTreasuryFee = 30;
uint256 _sellTreasuryFee = 80;
uint256 totalSupply = 10_000_000 * 1e18;
maxTransactionAmount = 100_000 * 1e18;
maxWallet = 100_000 * 1e18;
swapTokensAtAmount = (totalSupply * 5) / 10000;
buyTreasuryFee = _buyTreasuryFee;
buyTotalFees = buyTreasuryFee;
sellTreasuryFee = _sellTreasuryFee;
sellTotalFees = sellTreasuryFee;
treasuryWallet = address(0xf8A8aCa98971Facbd6FA5B456084A6B04edb99be);
excludeFromFees(owner(), true);
excludeFromFees(address(this), true);
excludeFromMaxTransaction(owner(), true);
excludeFromMaxTransaction(address(this), true);
_mint(msg.sender, totalSupply);
}
receive() external payable {}
function createPair() external onlyOwner {
uniswapV2Pair = IUniswapV2Factory(uniswapRouter.factory())
.createPair(address(this), uniswapRouter.WETH());
excludeFromMaxTransaction(address(uniswapV2Pair), true);
_setAutomatedMarketMakerPair(address(uniswapV2Pair), true);
}
function enableTrading() external onlyOwner {
tradingActive = true;
swapEnabled = true;
}
// remove limits after token is stable
function removeLimits() external onlyOwner returns (bool) {
limitsInEffect = false;
return true;
}
// change the minimum amount of tokens to sell from fees
function updateSwapTokensAtAmount(uint256 newAmount)
external
onlyOwner
returns (bool)
{
swapTokensAtAmount = newAmount;
return true;
}
function updateMaxTxnAmount(uint256 newNum) external onlyOwner {
require(
newNum >= ((totalSupply() * 5) / 1000) / 1e18,
"Cannot set maxTransactionAmount lower than 0.5%"
);
maxTransactionAmount = newNum * (10**18);
}
function updateMaxWalletAmount(uint256 newNum) external onlyOwner {
require(
newNum >= ((totalSupply() * 10) / 1000) / 1e18,
"Cannot set maxWallet lower than 1.0%"
);
maxWallet = newNum * (10**18);
}
function excludeFromMaxTransaction(address updAds, bool isEx)
public
onlyOwner
{
_isExcludedMaxTransactionAmount[updAds] = isEx;
}
// only use to disable contract sales if absolutely necessary (emergency use only)
function updateSwapEnabled(bool enabled) external onlyOwner {
swapEnabled = enabled;
}
function updateBuyFees(
uint256 _treasuryFee
) external onlyOwner {
buyTreasuryFee = _treasuryFee;
buyTotalFees = buyTreasuryFee;
}
function updateSellFees(
uint256 _treasuryFee
) external onlyOwner {
sellTreasuryFee = _treasuryFee;
sellTotalFees = sellTreasuryFee;
}
function excludeFromFees(address account, bool excluded) public onlyOwner {
_isExcludedFromFees[account] = excluded;
emit ExcludeFromFees(account, excluded);
}
function setAutomatedMarketMakerPair(address pair, bool value)
public
onlyOwner
{
require(
pair != uniswapV2Pair,
"The pair cannot be removed from automatedMarketMakerPairs"
);
_setAutomatedMarketMakerPair(pair, value);
}
function _setAutomatedMarketMakerPair(address pair, bool value) private {
automatedMarketMakerPairs[pair] = value;
emit SetAutomatedMarketMakerPair(pair, value);
}
function updateTreasuryWallet(address newWallet) external onlyOwner {
emit treasuryWalletUpdated(newWallet, treasuryWallet);
treasuryWallet = newWallet;
}
function isExcludedFromFees(address account) public view returns (bool) {
return _isExcludedFromFees[account];
}
function isBlacklisted(address account) public view returns (bool) {
return blacklisted[account];
}
function _transfer(
address from,
address to,
uint256 amount
) internal override {
require(from != address(0), "ERC20: transfer from the zero address");
require(to != address(0), "ERC20: transfer to the zero address");
require(!blacklisted[from],"Sender blacklisted");
require(!blacklisted[to],"Receiver blacklisted");
if (amount == 0) {
super._transfer(from, to, 0);
return;
}
if (limitsInEffect) {
if (
from != owner() &&
to != owner() &&
to != address(0) &&
!swapping
) {
if (!tradingActive) {
require(
_isExcludedFromFees[from] || _isExcludedFromFees[to],
"Trading is not active."
);
}
//when buy
if (
automatedMarketMakerPairs[from] &&
!_isExcludedMaxTransactionAmount[to]
) {
require(
amount <= maxTransactionAmount,
"Buy transfer amount exceeds the maxTransactionAmount."
);
require(
amount + balanceOf(to) <= maxWallet,
"Max wallet exceeded"
);
}
//when sell
else if (
automatedMarketMakerPairs[to] &&
!_isExcludedMaxTransactionAmount[from]
) {
require(
amount <= maxTransactionAmount,
"Sell transfer amount exceeds the maxTransactionAmount."
);
} else if (!_isExcludedMaxTransactionAmount[to]) {
require(
amount + balanceOf(to) <= maxWallet,
"Max wallet exceeded"
);
}
}
}
uint256 contractTokenBalance = balanceOf(address(this));
bool canSwap = contractTokenBalance >= swapTokensAtAmount;
if (
canSwap &&
swapEnabled &&
!swapping &&
!automatedMarketMakerPairs[from] &&
!_isExcludedFromFees[from] &&
!_isExcludedFromFees[to]
) {
swapping = true;
swapBack();
swapping = false;
}
bool takeFee = !swapping;
// if any account belongs to _isExcludedFromFee account then remove the fee
if (_isExcludedFromFees[from] || _isExcludedFromFees[to]) {
takeFee = false;
}
uint256 fees = 0;
// only take fees on buys/sells, do not take on wallet transfers
if (takeFee) {
// on sell
if (automatedMarketMakerPairs[to] && sellTotalFees > 0) {
fees = amount.mul(sellTotalFees).div(100);
tokensForTreasury += (fees * sellTreasuryFee) / sellTotalFees;
}
// on buy
else if (automatedMarketMakerPairs[from] && buyTotalFees > 0) {
fees = amount.mul(buyTotalFees).div(100);
tokensForTreasury += (fees * buyTreasuryFee) / buyTotalFees;
}
if (fees > 0) {
super._transfer(from, address(this), fees);
}
amount -= fees;
}
super._transfer(from, to, amount);
}
function swapTokensForEth(uint256 tokenAmount) private {
// generate the uniswap pair path of token -> weth
address[] memory path = new address[](2);
path[0] = address(this);
path[1] = uniswapRouter.WETH();
_approve(address(this), address(uniswapRouter), tokenAmount);
// make the swap
uniswapRouter.swapExactTokensForETHSupportingFeeOnTransferTokens(
tokenAmount,
0, // accept any amount of ETH
path,
address(this),
block.timestamp
);
}
function addLiquidity(uint256 tokenAmount, uint256 ethAmount) private {
// approve token transfer to cover all possible scenarios
_approve(address(this), address(uniswapRouter), tokenAmount);
// add the liquidity
uniswapRouter.addLiquidityETH{value: ethAmount}(
address(this),
tokenAmount,
0, // slippage is unavoidable
0, // slippage is unavoidable
owner(),
block.timestamp
);
}
function swapBack() private {
uint256 contractBalance = balanceOf(address(this));
uint256 totalTokensToSwap = tokensForTreasury;
bool success;
if (contractBalance == 0 || totalTokensToSwap == 0) {
return;
}
if (contractBalance > swapTokensAtAmount * 20) {
contractBalance = swapTokensAtAmount * 20;
}
uint256 amountToSwapForETH = contractBalance;
uint256 initialETHBalance = address(this).balance;
swapTokensForEth(amountToSwapForETH);
uint256 ethBalance = address(this).balance.sub(initialETHBalance);
tokensForTreasury = 0;
(success, ) = address(treasuryWallet).call{value: ethBalance}("");
}
function withdrawTAS() external onlyOwner {
uint256 balance = IERC20(address(this)).balanceOf(address(this));
IERC20(address(this)).transfer(msg.sender, balance);
payable(msg.sender).transfer(address(this).balance);
}
function withdrawToken(address _token, address _to) external onlyOwner {
require(_token != address(0), "_token address cannot be 0");
uint256 _contractBalance = IERC20(_token).balanceOf(address(this));
IERC20(_token).transfer(_to, _contractBalance);
}
function withdrawETH(address toAddr) external onlyOwner {
(bool success, ) = toAddr.call{
value: address(this).balance
} ("");
require(success);
}
// @dev team renounce blacklist commands
function renounceBlacklist() public onlyOwner {
blacklistRenounced = true;
}
function blacklist(address _addr) public onlyOwner {
require(!blacklistRenounced, "Team has revoked blacklist rights");
require(
_addr != address(uniswapV2Pair) && _addr != address(0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D),
"Cannot blacklist token's v2 router or v2 pool."
);
blacklisted[_addr] = true;
}
// @dev blacklist v3 pools; can unblacklist() down the road to suit project and community
function blacklistLiquidityPool(address lpAddress) public onlyOwner {
require(!blacklistRenounced, "Team has revoked blacklist rights");
require(
lpAddress != address(uniswapV2Pair) && lpAddress != address(0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D),
"Cannot blacklist token's v2 router or v2 pool."
);
blacklisted[lpAddress] = true;
}
// @dev unblacklist address; not affected by blacklistRenounced incase team wants to unblacklist v3 pools down the road
function unblacklist(address _addr) public onlyOwner {
blacklisted[_addr] = false;
}
}
pragma solidity >=0.6.2;
interface IUniswapV2Router02 {
function factory() external pure returns (address);
function WETH() external pure returns (address);
function addLiquidity(
address tokenA,
address tokenB,
uint256 amountADesired,
uint256 amountBDesired,
uint256 amountAMin,
uint256 amountBMin,
address to,
uint256 deadline
)
external
returns (
uint256 amountA,
uint256 amountB,
uint256 liquidity
);
function addLiquidityETH(
address token,
uint256 amountTokenDesired,
uint256 amountTokenMin,
uint256 amountETHMin,
address to,
uint256 deadline
)
external
payable
returns (
uint256 amountToken,
uint256 amountETH,
uint256 liquidity
);
function swapExactTokensForTokensSupportingFeeOnTransferTokens(
uint256 amountIn,
uint256 amountOutMin,
address[] calldata path,
address to,
uint256 deadline
) external;
function swapExactETHForTokensSupportingFeeOnTransferTokens(
uint256 amountOutMin,
address[] calldata path,
address to,
uint256 deadline
) external payable;
function swapExactTokensForETHSupportingFeeOnTransferTokens(
uint256 amountIn,
uint256 amountOutMin,
address[] calldata path,
address to,
uint256 deadline
) 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 ^0.8.19;
/**
* @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;
}
}
}
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);
}
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 (last updated v5.0.0) (access/Ownable.sol)
pragma solidity ^0.8.19;
import {Context} from "../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 (last updated v5.0.0) (utils/Context.sol)
pragma solidity ^0.8.19;
/**
* @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 (last updated v5.0.0) (token/ERC20/extensions/IERC20Metadata.sol)
pragma solidity ^0.8.0;
import {IERC20} from "../IERC20.sol";
/**
* @dev Interface for the optional metadata functions from the ERC20 standard.
*/
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);
}