Contract Source Code:
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "./IUniswapV2Router.sol";
import "./IUniswapV2Factory.sol";
import "./ERC20.sol";
contract MemeCoin is ERC20 {
uint256 public constant TOTAL_SUPPLY = 1000000000 * 10**18; // Total supply tokens = 1bn
uint256 public constant TOTAL_BUY_TOKENS = 800000000 * 10**18; // Total tokens to buy = 800mn
uint256 public constant LIQUIDITY_TOKENS = 200000000 * 10**18; // Total tokens to for LP = 200mn
uint256 public constant BUY_PRICE_DIFFERENCE_PERCENT = 1000; // Difference in buy price as percentage
uint256 public constant TARGET_LIQUIDITY = 4 * 10**18; // Target liquidity in ETH, assuming 18 decimals
address payable public constant REVENUE_ACCOUNT = payable(0xCDE357ABBdf15Da7CCE4B51CE70a1d0F08DfB782); // Fee collection address
uint256 public sanityTokenAmount = 100 * 10 ** 18;
uint8 public constant FEE_PERCENTAGE = 2; // Fee percentage
uint8 private buying; //tracks contract buying state to restrict pre-listing transfers
uint8 private selling;//tracks contract selling state to restrict pre-listing transfers
IUniswapV2Router public uniswapRouter;
address public lpAddress;
string public picture;
address public taxWallet;
address public bullaDeployer; //authorized address where all sales of the Memecoin are done from.
bool public listed;
bool public degen;
uint256 public totalETHBought; // Total ETH paid for tokens buying
uint256 public totalTokensBought; // Total tokens bought
uint256 public maxWalletAmount; // Total amount of tokens a wallet can hold
uint256 public buyTax;
uint256 public sellTax;
uint256 public devTaxTokens;// Tax tokens accumulated off all taxes {buy & sell}
mapping(address => uint256) public contributions; // Track ETH contributions
mapping(address => uint256) public tokens; // Track bought tokens
constructor(
address _bullaDeployer,
address _router,
address _taxWallet,
uint256 _maxWalletAmount,
uint256 _buyTax,
uint256 _sellTax,
string memory _name,
string memory _ticker,
string memory _picture,
bool _degen
) ERC20(_name, _ticker) {
bullaDeployer = _bullaDeployer;
uniswapRouter = IUniswapV2Router(_router);
if (_maxWalletAmount == 0) {
maxWalletAmount = type(uint256).max;//No Wallet limit
} else if(_maxWalletAmount == 1){
maxWalletAmount = (TOTAL_SUPPLY * 5) / 1000;//0.5% Wallet limit
} else if(_maxWalletAmount == 2){
maxWalletAmount = TOTAL_SUPPLY * 1 / 100; //1% Wallet limit
}
require(_maxWalletAmount == 0 || _maxWalletAmount == 1 || _maxWalletAmount == 2,'Invalid Max Wallet Amount');
picture = _picture;
taxWallet = _taxWallet;
buyTax = _buyTax;
sellTax = _sellTax;
degen = _degen;
listed = false;
totalETHBought = 0;
//Create Pair
lpAddress = IUniswapV2Factory(uniswapRouter.factory()).createPair(address(this), uniswapRouter.WETH());
//Max approve token for Router
_approve(address(this), address(uniswapRouter), type(uint256).max);
_mint(address(this), TOTAL_SUPPLY);
}
modifier onlyTaxWallet() {
require(tx.origin == taxWallet,"Unauthorized Reset Attempt");
_;
}
modifier onlyBulla() {
require(msg.sender == bullaDeployer,"Unauthorized Interaction");
_;
}
// @notice transfer function that handles all the buy and sell tax logic.
// @param sender this is the address of the user where tokens are sent from.
// @param recepient this the address of the user receiving the tokens.
// @param amount this is the amount of tokens to be sent.
function _transfer(address sender, address recipient, uint256 amount) internal override {
uint256 tax;
address _weth = uniswapRouter.WETH();
if (listed){
updateMaxWalletAmount(lpAddress,_weth);
//Buy tax
if (buyTax > 0 && sender == lpAddress && recipient != taxWallet){
tax = amount * buyTax / 100;
uint256 taxedAmount = amount - tax;
devTaxTokens = devTaxTokens + tax;
amount = taxedAmount;
super._transfer(sender, address(this), tax);
}
//Sell tax
if (sellTax > 0 && recipient == lpAddress && sender!= taxWallet){
tax = amount * sellTax / 100;
uint256 taxedAmount = amount - tax;
devTaxTokens = devTaxTokens + tax;
amount = taxedAmount;
super._transfer(sender, address(this), tax);
}
if (recipient != taxWallet && recipient != lpAddress && recipient != address(0x000000000000000000000000000000000000dEaD)) {
require(balanceOf(address(recipient)) + amount <= maxWalletAmount, "Transfer amount exceeds the max wallet amount");
}
super._transfer(sender, recipient, amount);
if(sender != lpAddress && recipient != lpAddress){
_swapAndLiquify();
}
}else{
//Make sure only token contract can send tokens before listing
if (recipient != address(this) || sender != address(this)) {
require(buying > 0 || selling > 0,"Pre-listing transfers Not Allowed");
buying = 0;
selling = 0;
}
if (recipient != taxWallet && recipient != address(this) && recipient != lpAddress) {
require(balanceOf(address(recipient)) + amount <= maxWalletAmount, "Transfer amount exceeds the max wallet amount");
}
super._transfer(sender, recipient, amount);
}
}
// @notice allows a user buy a memecoin by sending ETHER.
// @param buyer this is the address of the user buyingb the tokens.
// @param slippageAmount this is the minimum amount allowed by user to be received during the purchase.
function buyTokens(address buyer,uint256 slippageAmount) external payable onlyBulla {
require(!listed, "Liquidity is already added to Uniswap");
require(msg.value > 0, "Send ETH to buy tokens");
buying = 1;
uint256 fee = msg.value * uint256(FEE_PERCENTAGE) / 100;
uint256 ethAmount = msg.value - fee;
uint256 tokenAmount = calculateTokenAmount(ethAmount);
uint256 currentPrice = tokenAmount/ethAmount;
uint256 finalprice;
if (_getRemainingAmount() == msg.value) {
finalprice = currentPrice;
if(tokenAmount > (TOTAL_BUY_TOKENS - totalTokensBought)){
tokenAmount = TOTAL_BUY_TOKENS - totalTokensBought;
}
}
totalTokensBought += tokenAmount;
contributions[buyer] += ethAmount;
if(finalprice == 0){
require(tokenAmount >= slippageAmount, "Slippage Amount Restriction");
}
if(buyTax > 0 && buyer != taxWallet){
uint256 tax = tokenAmount * buyTax / 100;
uint256 buyerTokens = tokenAmount - tax;
devTaxTokens = devTaxTokens + tax;
tokens[buyer] += buyerTokens;
tokenAmount = buyerTokens;
}else{
tokens[buyer] += tokenAmount;
}
totalETHBought += ethAmount;
_transfer(address(this), buyer, tokenAmount);
bool success;
(success, ) = REVENUE_ACCOUNT.call{value: fee}("");
require(success, "Transfer failed");
if (address(this).balance >= TARGET_LIQUIDITY && !listed) {
_addLiquidity();
_burnRemainingTokens();
}
}
// @notice allows a user sell a memecoin.
// @param seller this is the address of the user selling tokens.
// @param tokenAmount this is the amount of tokens a user wants to sell.
function sellTokens(address seller,uint256 tokenAmount) external onlyBulla {
require(!listed, "Liquidity is already added to Uniswap");
require(tokenAmount > 0, "Amount must be greater than 0");
selling = 1;
uint256 ethAmount = calculateEthAmount(seller,tokenAmount);
if ((balanceOf(address(this)) + tokenAmount) == TOTAL_SUPPLY) {
ethAmount = address(this).balance;
if(!degen){
contributions[seller] = 0;
}
totalETHBought = 0;
} else {
if(!degen){
contributions[seller] -= ethAmount;
totalETHBought -= ethAmount;
}else{
if(contributions[seller] < ethAmount){
uint subAmount;
if(tokenAmount > 0 && tokenAmount <= (tokens[seller] * 25 / 100)){
subAmount = contributions[seller] * 25 / 100;
} else if (tokenAmount >= (tokens[seller] * 25 / 100) && tokenAmount <= (tokens[seller] * 50 / 100)){
subAmount = contributions[seller] * 50 / 100;
} else if (tokenAmount >= (tokens[seller] * 50 / 100) && tokenAmount <= (tokens[seller] * 75 / 100)){
subAmount = contributions[seller] * 75 / 100;
} else if (tokenAmount >= (tokens[seller] * 75 / 100) && tokenAmount <= (tokens[seller] * 100 / 100)){
subAmount = contributions[seller] * 100 / 100;
}
contributions[seller] = contributions[seller] - subAmount;
totalETHBought -= ethAmount;
}else{
totalETHBought -= ethAmount;
}
}
}
uint256 fee = ethAmount * uint256(FEE_PERCENTAGE) / 100;
if(sellTax > 0 && seller != taxWallet){
uint256 tax = tokenAmount * sellTax / 100;
uint256 sellerTokens = tokenAmount - tax;
tokens[seller] -= tokenAmount;
devTaxTokens = devTaxTokens + tax;
tokenAmount = sellerTokens;
}else{
tokens[seller] -= tokenAmount;
}
totalTokensBought -= tokenAmount;
_transfer(seller, address(this), tokenAmount);
bool success;
(success, ) = seller.call{value: ethAmount - fee}("");
require(success, "Transfer failed");
(success, ) = REVENUE_ACCOUNT.call{value: fee}("");
require(success, "Transfer failed");
}
// @notice call to get the remaining ETHER amount required to be spent by users for the memecoin to be listed.
// @returns A uint value indicating the remaining ETHER amount required to be spent by users for the memecoin to be listed.
function getRemainingAmount() public view returns (uint256) {
require(TARGET_LIQUIDITY > address(this).balance, "Liquidity target exceeded");
return _getRemainingAmount();
}
// @notice allows the user calculate the minimum amount required to be received during a buy.
// @param ethAmount this of ETHER to be used for the buy.
// @param slippageAllowance this is the amount in percentage used to calculate slippage.
function slippage(uint256 ethAmount,uint256 slippageAllowance) public view returns(uint256) {
uint256 fee = ethAmount * uint256(FEE_PERCENTAGE) / 100;
ethAmount = ethAmount - fee;
uint256 slippageAmount = calculateTokenAmount(ethAmount);
if (buyTax > 0) {
uint256 tax = slippageAmount * buyTax / 100;
slippageAmount = slippageAmount - tax;
}
slippageAllowance = slippageAmount * slippageAllowance / 100;
slippageAmount = slippageAmount - slippageAllowance;
return slippageAmount;
}
// @notice call to get the remaining ETHER amount required to be spent by users for the memecoin to be listed.
// @param ethAmount this an amount of ETHER to be used to buy.
// @returns A uint value indicating the token amount a user would receive.
function calculateTokenAmount(uint256 ethAmount) public view returns (uint256) {
require(totalETHBought + ethAmount <= TARGET_LIQUIDITY, "Liquidity target exceeded");
uint256 initialTokenPrice = _initialTokenPrice();
uint256 tokenPrice = initialTokenPrice + ((initialTokenPrice * BUY_PRICE_DIFFERENCE_PERCENT / 100) * (totalETHBought + (ethAmount / 6)) / TARGET_LIQUIDITY);
return ethAmount * 10**18 / tokenPrice;
}
// @notice call to get the ETHER amount sent to a user when tokens are sold.
// @param user this is the address of the user.
// @param tokenAmount this the amount of tokens a user want to sell.
// @returns A uint value indicating the ETHER amount a user would receive.
function calculateEthAmount(address user,uint256 tokenAmount) public view returns (uint256) {
uint256 userTokens = tokens[user];
require(userTokens >= tokenAmount, "Insufficient user token balance");
uint256 value;
if(!degen){
return contributions[user] * tokenAmount / userTokens;
}else{
if(contributions[user] < totalETHBought){
value = totalETHBought - contributions[user];
value = value / 5;
value = value + contributions[user];
}else{
value = totalETHBought;
}
return value * tokenAmount / userTokens;
}
}
// @notice allows the creator of a memecoin set the minimum amount required to be met before a swap of the tax tokens occurs.
// @param value this is the minimum amount required to be met before a swap of the tax tokens.
function setSanityTokenAmount(uint256 newValue) external onlyBulla onlyTaxWallet {
sanityTokenAmount = newValue * 10 ** 18;
}
// @notice allows the creator of a memecoin tax from the token.
function removeTaxFees() external onlyBulla onlyTaxWallet {
buyTax = 0;
sellTax = 0;
}
// @notice function that adds liqudity to Uniswap once the Target Liquidity is met.
function _addLiquidity() internal {
listed = true;
uniswapRouter.addLiquidityETH{ value: address(this).balance }(
address(this),
LIQUIDITY_TOKENS,
0,
0,
address(this),
block.timestamp
);
uint256 amount = IERC20(lpAddress).balanceOf(address(this));
//Burn LP
IERC20(lpAddress).transfer(address(0x000000000000000000000000000000000000dEaD),amount);
_swapAndLiquify();
}
// @notice function that burns the remaining tokens in the contract after liquidity is added.
function _burnRemainingTokens() internal {
uint256 amount;
if(devTaxTokens > 0){
amount = IERC20(address(this)).balanceOf(address(this)) - devTaxTokens;
}else{
amount = IERC20(address(this)).balanceOf(address(this));
}
//Burn Remaining Tokens
IERC20(address(this)).transfer(address(0x000000000000000000000000000000000000dEaD),amount);
}
// @notice fucntion that update the maxWalletAmount once the 6 ETHER requirement is met.
function updateMaxWalletAmount(address _lpToken,address _weth) internal {
if(maxWalletAmount == type(uint256).max) return;
uint256 amount = IERC20(_weth).balanceOf(address(_lpToken));
if (amount >= 6 ether) {
maxWalletAmount = type(uint256).max;
}
}
// @notice call to get the remaining ETHER amount required to be spent by users for the memecoin to be listed.
// @returns A uint value indicating the remaining ETHER amount required to be spent by users for the memecoin to be listed.
function _getRemainingAmount() internal view returns (uint256) {
return (TARGET_LIQUIDITY - totalETHBought) * 100 / (100 - uint256(FEE_PERCENTAGE));
}
// Get initial ETH normalized price per token
function _initialTokenPrice() internal pure returns (uint256){
return TARGET_LIQUIDITY * 10**18 / ((TOTAL_BUY_TOKENS * BUY_PRICE_DIFFERENCE_PERCENT) / 375);
}
// @notice function that swaps devTaxToken balance for ETHER.
function _swapAndLiquify() private {
if(devTaxTokens < sanityTokenAmount) return;
_swapTokensForEth(devTaxTokens);
devTaxTokens = 0;
}
// @notice function that executes the swaps devTaxToken balance for ETHER.
function _swapTokensForEth(uint256 tokenAmount) private {
address[] memory path = new address[](2);
path[0] = address(this);
path[1] = uniswapRouter.WETH();
uniswapRouter.swapExactTokensForETHSupportingFeeOnTransferTokens(
tokenAmount,
0,
path,
taxWallet,
block.timestamp
);
}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (token/ERC20/ERC20.sol)
pragma solidity ^0.8.0;
import "./IERC20.sol";
import "./IERC20Metadata.sol";
import "./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.openzeppelin.com/t/how-to-implement-erc20-supply-mechanisms/226[How
* to implement supply mechanisms].
*
* The default value of {decimals} is 18. To change this, you should override
* this function so it returns a different value.
*
* 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}.
*
* 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 default value returned by this function, unless
* it's 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:
*
* - `to` cannot be the zero address.
* - the caller must have a balance of at least `amount`.
*/
function transfer(address to, uint256 amount) public virtual override returns (bool) {
address owner = _msgSender();
_transfer(owner, to, 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}.
*
* NOTE: If `amount` is the maximum `uint256`, the allowance is not updated on
* `transferFrom`. This is semantically equivalent to an infinite approval.
*
* Requirements:
*
* - `spender` cannot be the zero address.
*/
function approve(address spender, uint256 amount) public virtual override returns (bool) {
address owner = _msgSender();
_approve(owner, 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}.
*
* NOTE: Does not update the allowance if the current allowance
* is the maximum `uint256`.
*
* Requirements:
*
* - `from` and `to` cannot be the zero address.
* - `from` must have a balance of at least `amount`.
* - the caller must have allowance for ``from``'s tokens of at least
* `amount`.
*/
function transferFrom(address from, address to, uint256 amount) public virtual override returns (bool) {
address spender = _msgSender();
_spendAllowance(from, spender, amount);
_transfer(from, to, 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) {
address owner = _msgSender();
_approve(owner, spender, allowance(owner, 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) {
address owner = _msgSender();
uint256 currentAllowance = allowance(owner, spender);
require(currentAllowance >= subtractedValue, "ERC20: decreased allowance below zero");
unchecked {
_approve(owner, spender, currentAllowance - subtractedValue);
}
return true;
}
/**
* @dev Moves `amount` of tokens from `from` to `to`.
*
* 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:
*
* - `from` cannot be the zero address.
* - `to` cannot be the zero address.
* - `from` must have a balance of at least `amount`.
*/
function _transfer(address from, address to, uint256 amount) internal virtual {
require(from != address(0), "ERC20: transfer from the zero address");
require(to != address(0), "ERC20: transfer to the zero address");
_beforeTokenTransfer(from, to, amount);
uint256 fromBalance = _balances[from];
require(fromBalance >= amount, "ERC20: transfer amount exceeds balance");
unchecked {
_balances[from] = fromBalance - amount;
// Overflow not possible: the sum of all balances is capped by totalSupply, and the sum is preserved by
// decrementing then incrementing.
_balances[to] += amount;
}
emit Transfer(from, to, amount);
_afterTokenTransfer(from, to, 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;
unchecked {
// Overflow not possible: balance + amount is at most totalSupply + amount, which is checked above.
_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;
// Overflow not possible: amount <= accountBalance <= totalSupply.
_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 Updates `owner` s allowance for `spender` based on spent `amount`.
*
* Does not update the allowance amount in case of infinite allowance.
* Revert if not enough allowance is available.
*
* Might emit an {Approval} event.
*/
function _spendAllowance(address owner, address spender, uint256 amount) internal virtual {
uint256 currentAllowance = allowance(owner, spender);
if (currentAllowance != type(uint256).max) {
require(currentAllowance >= amount, "ERC20: insufficient allowance");
unchecked {
_approve(owner, spender, currentAllowance - 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
pragma solidity ^0.8.0;
interface IUniswapV2Factory {
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);
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
interface IUniswapV2Router {
function WETH() external pure returns (address);
function addLiquidityETH(
address token,
uint amountTokenDesired,
uint amountTokenMin,
uint amountETHMin,
address to,
uint deadline
) external payable returns (uint amountToken, uint amountETH, uint liquidity);
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 getAmountsOut(uint256 amountIn, address[] memory path) external view returns (uint256[] memory amounts);
function factory() external pure returns (address);
function swapExactTokensForTokens(
uint amountIn,
uint amountOutMin,
address[] calldata path,
address to,
uint deadline
) external returns (uint[] memory amounts);
function swapExactTokensForETHSupportingFeeOnTransferTokens(
uint amountIn,
uint amountOutMin,
address[] calldata path,
address to,
uint deadline
) external;
}
// 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/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);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (token/ERC20/IERC20.sol)
pragma solidity ^0.8.0;
/**
* @dev Interface of the ERC20 standard as defined in the EIP.
*/
interface IERC20 {
/**
* @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);
/**
* @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 `to`.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* Emits a {Transfer} event.
*/
function transfer(address to, 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 `from` to `to` 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 from, address to, uint256 amount) external returns (bool);
}