// SPDX-License-Identifier: MITpragmasolidity ^0.8.17;import"lib/openzeppelin-contracts/contracts/token/ERC20/ERC20.sol";
import"lib/openzeppelin-contracts/contracts/access/Ownable.sol";
import"lib/uniswap-v2-core/contracts/interfaces/IUniswapV2Factory.sol";
import"lib/uniswap-v2-periphery/contracts/interfaces/IUniswapV2Router02.sol";
import"lib/openzeppelin-contracts/contracts/utils/math/SafeMath.sol";
contractAIONisERC20, Ownable{
usingSafeMathforuint256;
IUniswapV2Router02 publicimmutable uniswapV2Router;
addresspublicimmutable uniswapV2Pair;
boolprivate swapping;
addresspublic revShareWallet;
addresspublic teamWallet;
addresspublic buyBackWallet;
uint256public maxTransactionAmount;
uint256public swapTokensAtAmount;
uint256public maxWallet;
uint256public startBlock;
boolpublic limitsInEffect =true;
boolpublic tradingActive =false;
boolpublic swapEnabled =false;
boolpublic blacklistRenounced =false;
// Anti-bot and anti-whale mappings and variablesmapping(address=>bool) blacklisted;
uint256public buyTotalFees;
uint256public buyRevShareFee;
uint256public buyLiquidityFee;
uint256public buyTeamFee;
uint256public sellTotalFees;
uint256public sellRevShareFee;
uint256public sellLiquidityFee;
uint256public sellTeamFee;
uint256public buyBackFee;
uint256public tokensForRevShare;
uint256public tokensForLiquidity;
uint256public tokensForTeam;
uint256public tokensForBuyBack;
/******************/// exclude from fees and max transaction amountmapping(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 amountmapping(address=>bool) public automatedMarketMakerPairs;
eventUpdateUniswapV2Router(addressindexed newAddress,
addressindexed oldAddress
);
eventExcludeFromFees(addressindexed account, bool isExcluded);
eventSetAutomatedMarketMakerPair(addressindexed pair, boolindexed value);
eventrevShareWalletUpdated(addressindexed newWallet,
addressindexed oldWallet
);
eventbuyBackWalletUpdated(addressindexed newWallet,
addressindexed oldWallet
);
eventteamWalletUpdated(addressindexed newWallet,
addressindexed oldWallet
);
eventSwapAndLiquify(uint256 tokensSwapped,
uint256 ethReceived,
uint256 tokensIntoLiquidity
);
constructor() ERC20("AION", "AION") {
IUniswapV2Router02 _uniswapV2Router = IUniswapV2Router02(
0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D
);
excludeFromMaxTransaction(address(_uniswapV2Router), true);
uniswapV2Router = _uniswapV2Router;
uniswapV2Pair = IUniswapV2Factory(_uniswapV2Router.factory())
.createPair(address(this), _uniswapV2Router.WETH());
excludeFromMaxTransaction(address(uniswapV2Pair), true);
_setAutomatedMarketMakerPair(address(uniswapV2Pair), true);
uint256 _buyRevShareFee =0;
uint256 _buyLiquidityFee =0;
uint256 _buyTeamFee =4;
uint256 _sellRevShareFee =0;
uint256 _sellLiquidityFee =0;
uint256 _sellTeamFee =4;
uint256 _buyBackFee =1;
uint256 totalSupply =1_000_000*1e18;
maxTransactionAmount =2500*1e18; // 0.25%
maxWallet =2500*1e18; // 0.25%
swapTokensAtAmount = (totalSupply *5) /10000; // 0.05%
buyBackFee = _buyBackFee;
buyRevShareFee = _buyRevShareFee;
buyLiquidityFee = _buyLiquidityFee;
buyTeamFee = _buyTeamFee;
buyTotalFees = buyRevShareFee + buyLiquidityFee + buyTeamFee + buyBackFee;
sellRevShareFee = _sellRevShareFee;
sellLiquidityFee = _sellLiquidityFee;
sellTeamFee = _sellTeamFee;
sellTotalFees = sellRevShareFee + sellLiquidityFee + sellTeamFee + buyBackFee;
revShareWallet =address(0xe44Cb4dBD91648Cb6932f71729aaf0ddfA8b761D); // set as revShare wallet
buyBackWallet =address(0x99Ba381043475e78609D517685947402978c8233); // set as buyBack wallet
teamWallet =address(0xE43a6d169590f3245D7868Fe19de45AA377cc56a); // set as team wallet
blacklisted[address(0xE592427A0AEce92De3Edee1F18E0157C05861564)] =true; // uniswap v3 router// exclude from paying fees or having max transaction amount
excludeFromFees(owner(), true);
excludeFromFees(address(this), true);
excludeFromFees(address(0xdead), true);
excludeFromMaxTransaction(owner(), true);
excludeFromMaxTransaction(address(this), true);
excludeFromMaxTransaction(address(0xdead), true);
/*
_mint is an internal function in ERC20.sol that is only called here,
and CANNOT be called ever again
*/
_mint(msg.sender, totalSupply);
}
receive() externalpayable{}
// once enabled, can never be turned offfunctionenableTrading() externalonlyOwner{
tradingActive =true;
swapEnabled =true;
startBlock =block.number;
}
// remove limits after token is stablefunctionremoveLimits() externalonlyOwnerreturns (bool) {
limitsInEffect =false;
returntrue;
}
// change the minimum amount of tokens to sell from feesfunctionupdateSwapTokensAtAmount(uint256 newAmount)
externalonlyOwnerreturns (bool)
{
require(
newAmount >= (totalSupply() *1) /100000,
"Swap amount cannot be lower than 0.001% total supply."
);
require(
newAmount <= (totalSupply() *5) /1000,
"Swap amount cannot be higher than 0.5% total supply."
);
swapTokensAtAmount = newAmount;
returntrue;
}
functionupdateMaxTxnAmount(uint256 newNum) externalonlyOwner{
require(
newNum >= ((totalSupply() *5) /1000) /1e18,
"Cannot set maxTransactionAmount lower than 0.5%"
);
maxTransactionAmount = newNum * (10**18);
}
functionupdateMaxWalletAmount(uint256 newNum) externalonlyOwner{
require(
newNum >= ((totalSupply() *10) /1000) /1e18,
"Cannot set maxWallet lower than 1.0%"
);
maxWallet = newNum * (10**18);
}
functionexcludeFromMaxTransaction(address updAds, bool isEx)
publiconlyOwner{
_isExcludedMaxTransactionAmount[updAds] = isEx;
}
// only use to disable contract sales if absolutely necessary (emergency use only)functionupdateSwapEnabled(bool enabled) externalonlyOwner{
swapEnabled = enabled;
}
functionupdateBuyFees(uint256 _revShareFee,
uint256 _liquidityFee,
uint256 _teamFee,
uint256 _buyBackFee
) externalonlyOwner{
buyRevShareFee = _revShareFee;
buyLiquidityFee = _liquidityFee;
buyTeamFee = _teamFee;
buyBackFee = _buyBackFee;
buyTotalFees = buyRevShareFee + buyLiquidityFee + buyTeamFee + buyBackFee;
require(buyTotalFees <=5, "Buy fees must be <= 10.");
}
functionupdateSellFees(uint256 _revShareFee,
uint256 _liquidityFee,
uint256 _teamFee,
uint256 _buyBackFee
) externalonlyOwner{
sellRevShareFee = _revShareFee;
sellLiquidityFee = _liquidityFee;
sellTeamFee = _teamFee;
buyBackFee = _buyBackFee;
sellTotalFees = sellRevShareFee + sellLiquidityFee + sellTeamFee + buyBackFee;
require(sellTotalFees <=5, "Sell fees must be <= 10.");
}
functionexcludeFromFees(address account, bool excluded) publiconlyOwner{
_isExcludedFromFees[account] = excluded;
emit ExcludeFromFees(account, excluded);
}
functionsetAutomatedMarketMakerPair(address pair, bool value)
publiconlyOwner{
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);
}
functionupdateRevShareWallet(address newRevShareWallet) externalonlyOwner{
emit revShareWalletUpdated(newRevShareWallet, revShareWallet);
revShareWallet = newRevShareWallet;
}
functionupdateBuyBackWallet(address newBuyBackWallet) externalonlyOwner{
emit buyBackWalletUpdated(newBuyBackWallet, buyBackWallet);
buyBackWallet = newBuyBackWallet;
}
functionupdateTeamWallet(address newWallet) externalonlyOwner{
emit teamWalletUpdated(newWallet, teamWallet);
teamWallet = newWallet;
}
functionisExcludedFromFees(address account) publicviewreturns (bool) {
return _isExcludedFromFees[account];
}
functionisBlacklisted(address account) publicviewreturns (bool) {
return blacklisted[account];
}
functiongetMaxTXAmount() public{
uint256 relativeBlock =block.number- startBlock;
if (relativeBlock <4) {
maxTransactionAmount =2500*1e18;
} elseif (relativeBlock >=4&& relativeBlock <10) {
maxTransactionAmount =5000*1e18;
} else {
maxTransactionAmount =10000*1e18;
}
}
functiongetMaxWalletAmount() public{
uint256 relativeBlock =block.number- startBlock;
if (relativeBlock ==0) {
maxWallet =2500*1e18;
} elseif (relativeBlock >0&& relativeBlock <10) {
maxWallet =5000*1e18;
} else {
maxWallet =10000*1e18;
}
}
functiongetBuyFee() publicviewreturns (uint256) {
uint256 relativeBlock =block.number- startBlock;
// Adjust buy fee based on blockif (relativeBlock ==0) return75;
if (relativeBlock ==1) return70;
if (relativeBlock ==2) return60;
if (relativeBlock ==3) return50;
if (relativeBlock ==4) return40;
if (relativeBlock ==5) return30;
if (relativeBlock ==6) return20;
if (relativeBlock ==7) return10;
if (relativeBlock >=8) return buyTotalFees;
}
functiongetSellFee() publicviewreturns (uint256) {
uint256 relativeBlock =block.number- startBlock;
// Adjust buy fee based on blockif (relativeBlock ==0) return75;
if (relativeBlock ==1) return70;
if (relativeBlock ==2) return60;
if (relativeBlock ==3) return50;
if (relativeBlock ==4) return40;
if (relativeBlock ==5) return30;
if (relativeBlock ==6) return20;
if (relativeBlock ==7) return10;
if (relativeBlock >=8&& relativeBlock <20) return8;
if (relativeBlock >=20) return sellTotalFees;
}
function_transfer(addressfrom,
address to,
uint256 amount
) internaloverride{
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) &&
to !=address(0xdead) &&!swapping
) {
if (!tradingActive) {
require(
_isExcludedFromFees[from] || _isExcludedFromFees[to],
"Trading is not active."
);
}
getMaxTXAmount();
getMaxWalletAmount();
//when buyif (
automatedMarketMakerPairs[from] &&!_isExcludedMaxTransactionAmount[to]
) {
require(
amount <= maxTransactionAmount,
"Buy transfer amount exceeds the maxTransactionAmount."
);
require(
amount + balanceOf(to) <= maxWallet,
"Max wallet exceeded"
);
}
//when sellelseif (
automatedMarketMakerPairs[to] &&!_isExcludedMaxTransactionAmount[from]
) {
require(
amount <= maxTransactionAmount,
"Sell transfer amount exceeds the maxTransactionAmount."
);
} elseif (!_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 feeif (_isExcludedFromFees[from] || _isExcludedFromFees[to]) {
takeFee =false;
}
uint256 fees =0;
uint256 buyFees = getBuyFee();
uint256 sellFees = getSellFee();
// only take fees on buys/sells, do not take on wallet transfersif (takeFee) {
// on sellif (automatedMarketMakerPairs[to] && sellFees >0) {
fees = amount.mul(sellFees).div(100);
tokensForLiquidity += (fees * sellLiquidityFee) / sellFees;
tokensForTeam += (fees * sellTeamFee) / sellFees;
tokensForRevShare += (fees * sellRevShareFee) / sellFees;
tokensForBuyBack += (fees * buyBackFee) / sellFees;
}
// on buyelseif (automatedMarketMakerPairs[from] && buyFees >0) {
fees = amount.mul(buyFees).div(100);
tokensForLiquidity += (fees * buyLiquidityFee) / buyFees;
tokensForTeam += (fees * buyTeamFee) / buyFees;
tokensForRevShare += (fees * buyRevShareFee) / buyFees;
tokensForBuyBack += (fees * buyBackFee) / buyFees;
}
if (fees >0) {
super._transfer(from, address(this), fees);
}
amount -= fees;
}
super._transfer(from, to, amount);
}
functionswapTokensForEth(uint256 tokenAmount) private{
// generate the uniswap pair path of token -> wethaddress[] memory path =newaddress[](2);
path[0] =address(this);
path[1] = uniswapV2Router.WETH();
_approve(address(this), address(uniswapV2Router), tokenAmount);
// make the swap
uniswapV2Router.swapExactTokensForETHSupportingFeeOnTransferTokens(
tokenAmount,
0, // accept any amount of ETH
path,
address(this),
block.timestamp
);
}
functionaddLiquidity2(uint256 tokenAmount, uint256 ethAmount) private{
// approve token transfer to cover all possible scenarios
_approve(address(this), address(uniswapV2Router), tokenAmount);
// add the liquidity
uniswapV2Router.addLiquidityETH{value: ethAmount}(
address(this),
tokenAmount,
0, // slippage is unavoidable0, // slippage is unavoidable
owner(),
block.timestamp
);
}
functionswapBack() private{
uint256 contractBalance = balanceOf(address(this));
uint256 totalTokensToSwap = tokensForLiquidity + tokensForRevShare + tokensForTeam + tokensForBuyBack;
bool success;
if (contractBalance ==0|| totalTokensToSwap ==0) {
return;
}
if (contractBalance > swapTokensAtAmount *20) {
contractBalance = swapTokensAtAmount *20;
}
// Halve the amount of liquidity tokensuint256 liquidityTokens = (contractBalance * tokensForLiquidity) /
totalTokensToSwap /2;
uint256 amountToSwapForETH = contractBalance.sub(liquidityTokens);
uint256 initialETHBalance =address(this).balance;
swapTokensForEth(amountToSwapForETH);
uint256 ethBalance =address(this).balance.sub(initialETHBalance);
uint256 ethForRevShare = ethBalance.mul(tokensForRevShare).div(totalTokensToSwap - (tokensForLiquidity /2));
uint256 ethForTeam = ethBalance.mul(tokensForTeam).div(totalTokensToSwap - (tokensForLiquidity /2));
uint256 ethForBuyBack = ethBalance.mul(tokensForBuyBack).div(totalTokensToSwap - (tokensForLiquidity /2));
uint256 ethForLiquidity = ethBalance - ethForRevShare - ethForTeam - ethForBuyBack;
tokensForLiquidity =0;
tokensForRevShare =0;
tokensForTeam =0;
tokensForBuyBack =0;
(success, ) =address(teamWallet).call{value: ethForTeam}("");
(success, ) =address(buyBackWallet).call{value: ethForBuyBack}("");
if (liquidityTokens >0&& ethForLiquidity >0) {
addLiquidity2(liquidityTokens, ethForLiquidity);
emit SwapAndLiquify(
amountToSwapForETH,
ethForLiquidity,
tokensForLiquidity
);
}
(success, ) =address(revShareWallet).call{value: address(this).balance}("");
}
functionwithdrawStuckAion() externalonlyOwner{
uint256 balance = IERC20(address(this)).balanceOf(address(this));
IERC20(address(this)).transfer(msg.sender, balance);
payable(msg.sender).transfer(address(this).balance);
}
functionwithdrawStuckToken(address _token, address _to) externalonlyOwner{
require(_token !=address(0), "_token address cannot be 0");
uint256 _contractBalance = IERC20(_token).balanceOf(address(this));
IERC20(_token).transfer(_to, _contractBalance);
}
functionwithdrawStuckEth(address toAddr) externalonlyOwner{
(bool success, ) = toAddr.call{
value: address(this).balance
} ("");
require(success);
}
// @dev team renounce blacklist commandsfunctionrenounceBlacklist() publiconlyOwner{
blacklistRenounced =true;
}
functionblacklist(address _addr) publiconlyOwner{
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 communityfunctionblacklistLiquidityPool(address lpAddress) publiconlyOwner{
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 functionunblacklist(address _addr) publiconlyOwner{
blacklisted[_addr] =false;
}
}
Contract Source Code
File 2 of 10: Context.sol
// SPDX-License-Identifier: MIT// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)pragmasolidity ^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.
*/abstractcontractContext{
function_msgSender() internalviewvirtualreturns (address) {
returnmsg.sender;
}
function_msgData() internalviewvirtualreturns (bytescalldata) {
returnmsg.data;
}
}
Contract Source Code
File 3 of 10: ERC20.sol
// SPDX-License-Identifier: MIT// OpenZeppelin Contracts (last updated v4.9.0) (token/ERC20/ERC20.sol)pragmasolidity ^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.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}.
*/contractERC20isContext, IERC20, IERC20Metadata{
mapping(address=>uint256) private _balances;
mapping(address=>mapping(address=>uint256)) private _allowances;
uint256private _totalSupply;
stringprivate _name;
stringprivate _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(stringmemory name_, stringmemory symbol_) {
_name = name_;
_symbol = symbol_;
}
/**
* @dev Returns the name of the token.
*/functionname() publicviewvirtualoverridereturns (stringmemory) {
return _name;
}
/**
* @dev Returns the symbol of the token, usually a shorter version of the
* name.
*/functionsymbol() publicviewvirtualoverridereturns (stringmemory) {
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}.
*/functiondecimals() publicviewvirtualoverridereturns (uint8) {
return18;
}
/**
* @dev See {IERC20-totalSupply}.
*/functiontotalSupply() publicviewvirtualoverridereturns (uint256) {
return _totalSupply;
}
/**
* @dev See {IERC20-balanceOf}.
*/functionbalanceOf(address account) publicviewvirtualoverridereturns (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`.
*/functiontransfer(address to, uint256 amount) publicvirtualoverridereturns (bool) {
address owner = _msgSender();
_transfer(owner, to, amount);
returntrue;
}
/**
* @dev See {IERC20-allowance}.
*/functionallowance(address owner, address spender) publicviewvirtualoverridereturns (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.
*/functionapprove(address spender, uint256 amount) publicvirtualoverridereturns (bool) {
address owner = _msgSender();
_approve(owner, spender, amount);
returntrue;
}
/**
* @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`.
*/functiontransferFrom(addressfrom, address to, uint256 amount) publicvirtualoverridereturns (bool) {
address spender = _msgSender();
_spendAllowance(from, spender, amount);
_transfer(from, to, amount);
returntrue;
}
/**
* @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.
*/functionincreaseAllowance(address spender, uint256 addedValue) publicvirtualreturns (bool) {
address owner = _msgSender();
_approve(owner, spender, allowance(owner, spender) + addedValue);
returntrue;
}
/**
* @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`.
*/functiondecreaseAllowance(address spender, uint256 subtractedValue) publicvirtualreturns (bool) {
address owner = _msgSender();
uint256 currentAllowance = allowance(owner, spender);
require(currentAllowance >= subtractedValue, "ERC20: decreased allowance below zero");
unchecked {
_approve(owner, spender, currentAllowance - subtractedValue);
}
returntrue;
}
/**
* @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(addressfrom, address to, uint256 amount) internalvirtual{
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) internalvirtual{
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) internalvirtual{
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) internalvirtual{
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) internalvirtual{
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(addressfrom, address to, uint256 amount) internalvirtual{}
/**
* @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(addressfrom, address to, uint256 amount) internalvirtual{}
}
Contract Source Code
File 4 of 10: IERC20.sol
// SPDX-License-Identifier: MIT// OpenZeppelin Contracts (last updated v4.9.0) (token/ERC20/IERC20.sol)pragmasolidity ^0.8.0;/**
* @dev Interface of the ERC20 standard as defined in the EIP.
*/interfaceIERC20{
/**
* @dev Emitted when `value` tokens are moved from one account (`from`) to
* another (`to`).
*
* Note that `value` may be zero.
*/eventTransfer(addressindexedfrom, addressindexed 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.
*/eventApproval(addressindexed owner, addressindexed spender, uint256 value);
/**
* @dev Returns the amount of tokens in existence.
*/functiontotalSupply() externalviewreturns (uint256);
/**
* @dev Returns the amount of tokens owned by `account`.
*/functionbalanceOf(address account) externalviewreturns (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.
*/functiontransfer(address to, uint256 amount) externalreturns (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.
*/functionallowance(address owner, address spender) externalviewreturns (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.
*/functionapprove(address spender, uint256 amount) externalreturns (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.
*/functiontransferFrom(addressfrom, address to, uint256 amount) externalreturns (bool);
}
Contract Source Code
File 5 of 10: IERC20Metadata.sol
// SPDX-License-Identifier: MIT// OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/IERC20Metadata.sol)pragmasolidity ^0.8.0;import"../IERC20.sol";
/**
* @dev Interface for the optional metadata functions from the ERC20 standard.
*
* _Available since v4.1._
*/interfaceIERC20MetadataisIERC20{
/**
* @dev Returns the name of the token.
*/functionname() externalviewreturns (stringmemory);
/**
* @dev Returns the symbol of the token.
*/functionsymbol() externalviewreturns (stringmemory);
/**
* @dev Returns the decimals places of the token.
*/functiondecimals() externalviewreturns (uint8);
}
// SPDX-License-Identifier: MIT// OpenZeppelin Contracts (last updated v4.9.0) (access/Ownable.sol)pragmasolidity ^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.
*/abstractcontractOwnableisContext{
addressprivate _owner;
eventOwnershipTransferred(addressindexed previousOwner, addressindexed newOwner);
/**
* @dev Initializes the contract setting the deployer as the initial owner.
*/constructor() {
_transferOwnership(_msgSender());
}
/**
* @dev Throws if called by any account other than the owner.
*/modifieronlyOwner() {
_checkOwner();
_;
}
/**
* @dev Returns the address of the current owner.
*/functionowner() publicviewvirtualreturns (address) {
return _owner;
}
/**
* @dev Throws if the sender is not the owner.
*/function_checkOwner() internalviewvirtual{
require(owner() == _msgSender(), "Ownable: caller is not the owner");
}
/**
* @dev Leaves the contract without owner. It will not be possible to call
* `onlyOwner` functions. Can only be called by the current owner.
*
* NOTE: Renouncing ownership will leave the contract without an owner,
* thereby disabling any functionality that is only available to the owner.
*/functionrenounceOwnership() publicvirtualonlyOwner{
_transferOwnership(address(0));
}
/**
* @dev Transfers ownership of the contract to a new account (`newOwner`).
* Can only be called by the current owner.
*/functiontransferOwnership(address newOwner) publicvirtualonlyOwner{
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) internalvirtual{
address oldOwner = _owner;
_owner = newOwner;
emit OwnershipTransferred(oldOwner, newOwner);
}
}
Contract Source Code
File 10 of 10: SafeMath.sol
// SPDX-License-Identifier: MIT// OpenZeppelin Contracts (last updated v4.9.0) (utils/math/SafeMath.sol)pragmasolidity ^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.
*/librarySafeMath{
/**
* @dev Returns the addition of two unsigned integers, with an overflow flag.
*
* _Available since v3.4._
*/functiontryAdd(uint256 a, uint256 b) internalpurereturns (bool, uint256) {
unchecked {
uint256 c = a + b;
if (c < a) return (false, 0);
return (true, c);
}
}
/**
* @dev Returns the subtraction of two unsigned integers, with an overflow flag.
*
* _Available since v3.4._
*/functiontrySub(uint256 a, uint256 b) internalpurereturns (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._
*/functiontryMul(uint256 a, uint256 b) internalpurereturns (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/522if (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._
*/functiontryDiv(uint256 a, uint256 b) internalpurereturns (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._
*/functiontryMod(uint256 a, uint256 b) internalpurereturns (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.
*/functionadd(uint256 a, uint256 b) internalpurereturns (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.
*/functionsub(uint256 a, uint256 b) internalpurereturns (uint256) {
return a - b;
}
/**
* @dev Returns the multiplication of two unsigned integers, reverting on
* overflow.
*
* Counterpart to Solidity's `*` operator.
*
* Requirements:
*
* - Multiplication cannot overflow.
*/functionmul(uint256 a, uint256 b) internalpurereturns (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.
*/functiondiv(uint256 a, uint256 b) internalpurereturns (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.
*/functionmod(uint256 a, uint256 b) internalpurereturns (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.
*/functionsub(uint256 a, uint256 b, stringmemory errorMessage) internalpurereturns (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.
*/functiondiv(uint256 a, uint256 b, stringmemory errorMessage) internalpurereturns (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.
*/functionmod(uint256 a, uint256 b, stringmemory errorMessage) internalpurereturns (uint256) {
unchecked {
require(b >0, errorMessage);
return a % b;
}
}
}