Contract Source Code:
pragma solidity 0.8.20;
// SPDX-License-Identifier: MIT
/**
Website: https://0xgasless.com
X (Twitter): https://x.com/0xGasless
TG: https://t.me/Gasless0x
**/
import "@openzeppelin/contracts/utils/cryptography/draft-EIP712.sol";
abstract contract Context {
function _msgSender() internal view virtual returns (address) {
return msg.sender;
}
function _msgData() internal view virtual returns (bytes calldata) {
this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
return msg.data;
}
}
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);
}
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);
}
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");
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);
}
/** @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");
_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);
}
/**
* @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);
}
}
}
}
contract Ownable is Context {
address private _owner;
event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
constructor () {
address msgSender = _msgSender();
_owner = msgSender;
emit OwnershipTransferred(address(0), msgSender);
}
function owner() public view returns (address) {
return _owner;
}
modifier onlyOwner() {
require(_owner == _msgSender(), "Ownable: caller is not the owner");
_;
}
function renounceOwnership() external virtual onlyOwner {
emit OwnershipTransferred(_owner, address(0));
_owner = address(0);
}
function transferOwnership(address newOwner) public virtual onlyOwner {
require(newOwner != address(0), "Ownable: new owner is the zero address");
emit OwnershipTransferred(_owner, newOwner);
_owner = newOwner;
}
}
library Address {
function isContract(address account) internal view returns (bool) {
return account.code.length > 0;
}
function sendValue(address payable recipient, uint256 amount) internal {
require(address(this).balance >= amount, "Address: insufficient balance");
(bool success, ) = recipient.call{value: amount}("");
require(success, "Address: unable to send value, recipient may have reverted");
}
function functionCall(address target, bytes memory data) internal returns (bytes memory) {
return functionCallWithValue(target, data, 0, "Address: low-level call failed");
}
function functionCall(
address target,
bytes memory data,
string memory errorMessage
) internal returns (bytes memory) {
return functionCallWithValue(target, data, 0, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but also transferring `value` wei to `target`.
*
* Requirements:
*
* - the calling contract must have an ETH balance of at least `value`.
* - the called Solidity function must be `payable`.
*
* _Available since v3.1._
*/
function functionCallWithValue(
address target,
bytes memory data,
uint256 value
) internal returns (bytes memory) {
return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
}
/**
* @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
* with `errorMessage` as a fallback revert reason when `target` reverts.
*
* _Available since v3.1._
*/
function functionCallWithValue(
address target,
bytes memory data,
uint256 value,
string memory errorMessage
) internal returns (bytes memory) {
require(address(this).balance >= value, "Address: insufficient balance for call");
(bool success, bytes memory returndata) = target.call{value: value}(data);
return verifyCallResultFromTarget(target, success, returndata, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but performing a static call.
*
* _Available since v3.3._
*/
function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
return functionStaticCall(target, data, "Address: low-level static call failed");
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
* but performing a static call.
*
* _Available since v3.3._
*/
function functionStaticCall(
address target,
bytes memory data,
string memory errorMessage
) internal view returns (bytes memory) {
(bool success, bytes memory returndata) = target.staticcall(data);
return verifyCallResultFromTarget(target, success, returndata, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but performing a delegate call.
*
* _Available since v3.4._
*/
function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
return functionDelegateCall(target, data, "Address: low-level delegate call failed");
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
* but performing a delegate call.
*
* _Available since v3.4._
*/
function functionDelegateCall(
address target,
bytes memory data,
string memory errorMessage
) internal returns (bytes memory) {
(bool success, bytes memory returndata) = target.delegatecall(data);
return verifyCallResultFromTarget(target, success, returndata, errorMessage);
}
/**
* @dev Tool to verify that a low level call to smart-contract was successful, and revert (either by bubbling
* the revert reason or using the provided one) in case of unsuccessful call or if target was not a contract.
*
* _Available since v4.8._
*/
function verifyCallResultFromTarget(
address target,
bool success,
bytes memory returndata,
string memory errorMessage
) internal view returns (bytes memory) {
if (success) {
if (returndata.length == 0) {
// only check isContract if the call was successful and the return data is empty
// otherwise we already know that it was a contract
require(isContract(target), "Address: call to non-contract");
}
return returndata;
} else {
_revert(returndata, errorMessage);
}
}
/**
* @dev Tool to verify that a low level call was successful, and revert if it wasn't, either by bubbling the
* revert reason or using the provided one.
*
* _Available since v4.3._
*/
function verifyCallResult(
bool success,
bytes memory returndata,
string memory errorMessage
) internal pure returns (bytes memory) {
if (success) {
return returndata;
} else {
_revert(returndata, errorMessage);
}
}
function _revert(bytes memory returndata, string memory errorMessage) private pure {
// Look for revert reason and bubble it up if present
if (returndata.length > 0) {
// The easiest way to bubble the revert reason is using memory via assembly
/// @solidity memory-safe-assembly
assembly {
let returndata_size := mload(returndata)
revert(add(32, returndata), returndata_size)
}
} else {
revert(errorMessage);
}
}
}
library SafeERC20 {
using Address for address;
function safeTransfer(IERC20 token, address to, uint256 value) internal {
_callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
}
function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal {
_callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
}
function _callOptionalReturn(IERC20 token, bytes memory data) private {
bytes memory returndata = address(token).functionCall(data, "SafeERC20: low-level call failed");
if (returndata.length > 0) {
require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
}
}
function safeApprove(IERC20 token, address spender, uint256 value) internal {
// safeApprove should only be called when setting an initial allowance,
// or when resetting it to zero. To increase and decrease it, use
// 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
require(
(value == 0) || (token.allowance(address(this), spender) == 0),
"SafeERC20: approve from non-zero to non-zero allowance"
);
_callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
}
}
interface ILpPair {
function sync() external;
}
interface IDexRouter {
function factory() external pure returns (address);
function WETH() external pure returns (address);
function swapExactTokensForETHSupportingFeeOnTransferTokens(uint amountIn, uint amountOutMin, address[] calldata path, address to, uint deadline) external;
function swapExactETHForTokensSupportingFeeOnTransferTokens(
uint amountOutMin,
address[] calldata path,
address to,
uint deadline
) external payable;
function getAmountsOut(uint amountIn, address[] calldata path) external view returns (uint[] memory amounts);
function getAmountsIn(uint amountOut, address[] calldata path) external view returns (uint[] memory amounts);
}
interface IDexFactory {
function createPair(address tokenA, address tokenB) external returns (address pair);
}
library SafeMath {
function add(uint256 a, uint256 b) internal pure returns (uint256) {
uint256 c = a + b;
require(c >= a, 'SafeMath: addition overflow');
return c;
}
function sub(uint256 a, uint256 b) internal pure returns (uint256) {
return sub(a, b, 'SafeMath: subtraction overflow');
}
function sub(
uint256 a,
uint256 b,
string memory errorMessage
) internal pure returns (uint256) {
require(b <= a, errorMessage);
uint256 c = a - b;
return c;
}
function mul(uint256 a, uint256 b) internal pure returns (uint256) {
// Gas optimization: this is cheaper than requiring 'a' not being zero, but the
// benefit is lost if 'b' is also tested.
// See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
if (a == 0) {
return 0;
}
uint256 c = a * b;
require(c / a == b, 'SafeMath: multiplication overflow');
return c;
}
function div(uint256 a, uint256 b) internal pure returns (uint256) {
return div(a, b, 'SafeMath: division by zero');
}
function div(
uint256 a,
uint256 b,
string memory errorMessage
) internal pure returns (uint256) {
require(b > 0, errorMessage);
uint256 c = a / b;
// assert(a == b * c + a % b); // There is no case in which this doesn't hold
return c;
}
function mod(uint256 a, uint256 b) internal pure returns (uint256) {
return mod(a, b, 'SafeMath: modulo by zero');
}
function mod(
uint256 a,
uint256 b,
string memory errorMessage
) internal pure returns (uint256) {
require(b != 0, errorMessage);
return a % b;
}
function min(uint256 x, uint256 y) internal pure returns (uint256 z) {
z = x < y ? x : y;
}
function sqrt(uint256 y) internal pure returns (uint256 z) {
if (y > 3) {
z = y;
uint256 x = y / 2 + 1;
while (x < z) {
z = x;
x = (y / x + x) / 2;
}
} else if (y != 0) {
z = 1;
}
}
}
library SafeMathInt {
int256 private constant MIN_INT256 = int256(1) << 255;
int256 private constant MAX_INT256 = ~(int256(1) << 255);
/**
* @dev Multiplies two int256 variables and fails on overflow.
*/
function mul(int256 a, int256 b) internal pure returns (int256) {
int256 c = a * b;
// Detect overflow when multiplying MIN_INT256 with -1
require(c != MIN_INT256 || (a & MIN_INT256) != (b & MIN_INT256));
require((b == 0) || (c / b == a));
return c;
}
/**
* @dev Division of two int256 variables and fails on overflow.
*/
function div(int256 a, int256 b) internal pure returns (int256) {
// Prevent overflow when dividing MIN_INT256 by -1
require(b != -1 || a != MIN_INT256);
// Solidity already throws when dividing by 0.
return a / b;
}
/**
* @dev Subtracts two int256 variables and fails on overflow.
*/
function sub(int256 a, int256 b) internal pure returns (int256) {
int256 c = a - b;
require((b >= 0 && c <= a) || (b < 0 && c > a));
return c;
}
/**
* @dev Adds two int256 variables and fails on overflow.
*/
function add(int256 a, int256 b) internal pure returns (int256) {
int256 c = a + b;
require((b >= 0 && c >= a) || (b < 0 && c < a));
return c;
}
/**
* @dev Converts to absolute value, and fails on overflow.
*/
function abs(int256 a) internal pure returns (int256) {
require(a != MIN_INT256);
return a < 0 ? -a : a;
}
function toUint256Safe(int256 a) internal pure returns (uint256) {
require(a >= 0);
return uint256(a);
}
}
library SafeMathUint {
function toInt256Safe(uint256 a) internal pure returns (int256) {
int256 b = int256(a);
require(b >= 0);
return b;
}
}
interface DividendPayingContractOptionalInterface {
function withdrawableDividendOf(address _owner) external view returns(uint256);
function withdrawnDividendOf(address _owner) external view returns(uint256);
function accumulativeDividendOf(address _owner) external view returns(uint256);
}
interface DividendPayingContractInterface {
function dividendOf(address _owner) external view returns(uint256);
function distributeDividends() external payable;
function withdrawDividend() external;
event DividendsDistributed(
address indexed from,
uint256 weiAmount
);
event DividendWithdrawn(
address indexed to,
uint256 weiAmount
);
}
contract DividendPayingContract is DividendPayingContractInterface, DividendPayingContractOptionalInterface, Ownable {
using SafeMath for uint256;
using SafeMathUint for uint256;
using SafeMathInt for int256;
uint256 constant internal magnitude = 2**128;
uint256 internal magnifiedDividendPerShare;
mapping(address => int256) internal magnifiedDividendCorrections;
mapping(address => uint256) internal withdrawnDividends;
mapping (address => uint256) public holderBalance;
uint256 public totalBalance;
uint256 public totalDividendsDistributed;
receive() external payable {
distributeDividends();
}
function distributeDividends() public override payable {
if(totalBalance > 0 && msg.value > 0){
magnifiedDividendPerShare = magnifiedDividendPerShare.add(
(msg.value).mul(magnitude) / totalBalance
);
emit DividendsDistributed(msg.sender, msg.value);
totalDividendsDistributed = totalDividendsDistributed.add(msg.value);
}
}
function withdrawDividend() external virtual override {
_withdrawDividendOfUser(payable(msg.sender));
}
function _withdrawDividendOfUser(address payable user) internal returns (uint256) {
uint256 _withdrawableDividend = withdrawableDividendOf(user);
if (_withdrawableDividend > 0) {
withdrawnDividends[user] = withdrawnDividends[user].add(_withdrawableDividend);
emit DividendWithdrawn(user, _withdrawableDividend);
(bool success,) = user.call{value: _withdrawableDividend}("");
if(!success) {
withdrawnDividends[user] = withdrawnDividends[user].sub(_withdrawableDividend);
return 0;
}
return _withdrawableDividend;
}
return 0;
}
function withdrawDividendOfUserForCompound(address payable user) external onlyOwner returns (uint256 _withdrawableDividend) {
_withdrawableDividend = withdrawableDividendOf(user);
if (_withdrawableDividend > 0) {
withdrawnDividends[user] = withdrawnDividends[user] + _withdrawableDividend;
emit DividendWithdrawn(user, _withdrawableDividend);
}
(bool success,) = owner().call{value: _withdrawableDividend}("");
if(!success) {
withdrawnDividends[user] = withdrawnDividends[user].sub(_withdrawableDividend);
return 0;
}
}
function dividendOf(address _owner) external view override returns(uint256) {
return withdrawableDividendOf(_owner);
}
function withdrawableDividendOf(address _owner) public view override returns(uint256) {
return accumulativeDividendOf(_owner).sub(withdrawnDividends[_owner]);
}
function withdrawnDividendOf(address _owner) external view override returns(uint256) {
return withdrawnDividends[_owner];
}
function accumulativeDividendOf(address _owner) public view override returns(uint256) {
return magnifiedDividendPerShare.mul(holderBalance[_owner]).toInt256Safe()
.add(magnifiedDividendCorrections[_owner]).toUint256Safe() / magnitude;
}
function _increase(address account, uint256 value) internal {
magnifiedDividendCorrections[account] = magnifiedDividendCorrections[account]
.sub( (magnifiedDividendPerShare.mul(value)).toInt256Safe() );
}
function _reduce(address account, uint256 value) internal {
magnifiedDividendCorrections[account] = magnifiedDividendCorrections[account]
.add( (magnifiedDividendPerShare.mul(value)).toInt256Safe() );
}
function _setBalance(address account, uint256 newBalance) internal {
uint256 currentBalance = holderBalance[account];
holderBalance[account] = newBalance;
if(newBalance > currentBalance) {
uint256 increaseAmount = newBalance.sub(currentBalance);
_increase(account, increaseAmount);
totalBalance += increaseAmount;
} else if(newBalance < currentBalance) {
uint256 reduceAmount = currentBalance.sub(newBalance);
_reduce(account, reduceAmount);
totalBalance -= reduceAmount;
}
}
}
contract RevShare is DividendPayingContract {
event Claim(address indexed account, uint256 amount, bool indexed automatic);
mapping (address => bool) public excludedFromDividends;
constructor() {}
function getAccount(address _account)
public view returns (
address account,
uint256 withdrawableDividends,
uint256 totalDividends,
uint256 balance) {
account = _account;
withdrawableDividends = withdrawableDividendOf(account);
totalDividends = accumulativeDividendOf(account);
balance = holderBalance[account];
}
function setBalance(address payable account, uint256 newBalance) external onlyOwner {
if(excludedFromDividends[account]) {
return;
}
_setBalance(account, newBalance);
processAccount(account, true);
}
function processAccount(address payable account, bool automatic) public onlyOwner returns (bool) {
uint256 amount = _withdrawDividendOfUser(account);
if(amount > 0) {
emit Claim(account, amount, automatic);
return true;
}
return false;
}
function getTotalDividendsDistributed() external view returns (uint256) {
return totalDividendsDistributed;
}
function dividendTokenBalanceOf(address account) public view returns (uint256) {
return holderBalance[account];
}
function getNumberOfDividends() external view returns(uint256) {
return totalBalance;
}
function excludeFromDividends(address account) external onlyOwner {
excludedFromDividends[account] = true;
_setBalance(account, 0);
}
function includeInDividends(address account) external onlyOwner {
require(excludedFromDividends[account]);
excludedFromDividends[account] = false;
_setBalance(account, IERC20(owner()).balanceOf(account)); // sets balance back to token balance
}
}
contract OxGasless is ERC20, Ownable, EIP712 {
mapping (address => bool) public excludedFromFees;
mapping (address => bool) public excludedFromLimits;
string private constant SIGNING_DOMAIN = "0xGasless";
string private constant SIGNATURE_VERSION = "1";
bool public launched;
mapping (address => bool) public isAMMPair;
address public mktingAddress;
address public devAddress;
Tax public buyTax;
Tax public sellTax;
RevShare public revShare;
TokenDistributionForTax public tokensForTax;
TxLimits public txLimits;
bool public txLimitsActive = true;
mapping(address => uint256) private _holderLastTransferBlock; // MEV protection
bool public antiSandwichEnabled = true;
uint256 public swapTokensAtAmount;
address public pair;
IDexRouter public dexRouter;
address public immutable WETH;
uint64 public constant FEE_DIVISOR = 10000;
// structs
struct TxLimits {
uint128 transactionLimit;
uint128 walletLimit;
}
struct Tax {
uint48 mktingTax;
uint48 devTax;
uint48 lpTax;
uint48 revShareTax;
uint48 totalTax;
}
struct TokenDistributionForTax {
uint64 tokensForMkting;
uint64 tokensForLP;
uint64 tokensForDev;
uint64 tokensForRevShare;
bool gasSaver;
}
// events
event UpdatedTransactionLimit(uint newMax);
event UpdatedWalletLimit(uint newMax);
event SetExcludedFromFees(address _address, bool _isExcluded);
event SetExcludedFromLimits(address _address, bool _isExcluded);
event RemovedLimits();
event BuyTaxUpdated(uint newAmount);
event SellTaxUpdated(uint newAmount);
// constructor
constructor()
ERC20("0xGasless", "$0xGas")
EIP712(SIGNING_DOMAIN, SIGNATURE_VERSION)
{
_mint(msg.sender, 11_000_000 * 1e18);
address _v2Router;
// @dev assumes WETH pair
if(block.chainid == 1){
_v2Router = 0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D;
} else if(block.chainid == 5){
_v2Router = 0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D;
} else {
revert("Chain not configured");
}
revShare = new RevShare();
dexRouter = IDexRouter(_v2Router);
txLimits.transactionLimit = uint128(totalSupply() * 20 / 1000);
txLimits.walletLimit = uint128(totalSupply() * 2 / 100);
swapTokensAtAmount = totalSupply() * 25 / 100000;
mktingAddress = 0x87369cf387905EAB08A832F05a36E442C6EaE1A5; // update
devAddress = 0x87369cf387905EAB08A832F05a36E442C6EaE1A5; // update
buyTax.mktingTax = 400;
buyTax.lpTax = 100;
buyTax.devTax = 0;
buyTax.revShareTax = 0;
buyTax.totalTax = buyTax.mktingTax + buyTax.lpTax + buyTax.devTax + buyTax.revShareTax;
sellTax.mktingTax = 400;
sellTax.lpTax = 100;
sellTax.devTax = 0;
sellTax.revShareTax = 0;
sellTax.totalTax = sellTax.mktingTax + sellTax.lpTax + sellTax.devTax + buyTax.revShareTax + sellTax.revShareTax;
tokensForTax.gasSaver = true;
WETH = dexRouter.WETH();
pair = IDexFactory(dexRouter.factory()).createPair(address(this), WETH);
isAMMPair[pair] = true;
excludedFromLimits[pair] = true;
excludedFromLimits[msg.sender] = true;
excludedFromLimits[address(this)] = true;
excludedFromLimits[_v2Router] = true;
excludedFromFees[msg.sender] = true;
excludedFromFees[address(this)] = true;
excludedFromFees[address(0xdead)] = true;
excludedFromFees[_v2Router] = true;
revShare.excludeFromDividends(address(this));
revShare.excludeFromDividends(address(pair));
revShare.excludeFromDividends(address(0xdead));
_approve(address(this), address(dexRouter), type(uint256).max);
_approve(address(msg.sender), address(dexRouter), totalSupply());
}
function _transfer(
address from,
address to,
uint256 amount
) internal virtual override {
if(!excludedFromFees[from] && !excludedFromFees[to]){
require(launched, "Trading not active");
checkLimits(from, to, amount);
amount -= handleTax(from, to, amount);
}
super._transfer(from,to,amount);
revShare.setBalance(payable(to), balanceOf(to));
revShare.setBalance(payable(from), balanceOf(from));
}
function checkLimits(address from, address to, uint256 amount) internal {
if(txLimitsActive){
bool exFromLimitsTo = excludedFromLimits[to];
uint256 balanceOfTo = balanceOf(to);
TxLimits memory _txLimits = txLimits;
// buy
if (isAMMPair[from] && !exFromLimitsTo) {
require(amount <= _txLimits.transactionLimit, "Max Txn");
require(amount + balanceOfTo <= _txLimits.walletLimit, "Max Wallet");
}
// sell
else if (isAMMPair[to] && !excludedFromLimits[from]) {
require(amount <= _txLimits.transactionLimit, "Max Txn");
}
else if(!exFromLimitsTo) {
require(amount + balanceOfTo <= _txLimits.walletLimit, "Max Wallet");
}
}
if (antiSandwichEnabled){
if(isAMMPair[to]){
require(_holderLastTransferBlock[from] < block.number, "Anti MEV");
} else {
_holderLastTransferBlock[to] = block.number;
_holderLastTransferBlock[tx.origin] = block.number;
}
}
}
function handleTax(address from, address to, uint256 amount) internal returns (uint256){
if(balanceOf(address(this)) >= swapTokensAtAmount && !isAMMPair[from]) {
convertTax();
}
uint128 tax = 0;
Tax memory taxes;
if (isAMMPair[to]){
taxes = sellTax;
} else if(isAMMPair[from]){
taxes = buyTax;
}
if(taxes.totalTax > 0){
TokenDistributionForTax memory tokensForTaxUpdate = tokensForTax;
tax = uint128(amount * taxes.totalTax / FEE_DIVISOR);
tokensForTaxUpdate.tokensForLP += uint64(tax * taxes.lpTax / taxes.totalTax / 1e9);
tokensForTaxUpdate.tokensForMkting += uint64(tax * taxes.mktingTax / taxes.totalTax / 1e9);
tokensForTaxUpdate.tokensForDev += uint64(tax * taxes.devTax / taxes.totalTax / 1e9);
tokensForTaxUpdate.tokensForRevShare += uint64(tax * taxes.revShareTax / taxes.totalTax / 1e9);
tokensForTax = tokensForTaxUpdate;
super._transfer(from, address(this), tax);
}
return tax;
}
function swapTokensForETH(uint256 tokenAmount) private {
address[] memory path = new address[](2);
path[0] = address(this);
path[1] = WETH;
dexRouter.swapExactTokensForETHSupportingFeeOnTransferTokens(
tokenAmount,
0,
path,
address(this),
block.timestamp
);
}
function convertTax() private {
uint256 contractBalance = balanceOf(address(this));
TokenDistributionForTax memory tokensForTaxMem = tokensForTax;
uint256 totalTokensToSwap = tokensForTaxMem.tokensForLP + tokensForTaxMem.tokensForMkting + tokensForTaxMem.tokensForDev + tokensForTaxMem.tokensForRevShare;
if(contractBalance == 0 || totalTokensToSwap == 0) {return;}
if(contractBalance > swapTokensAtAmount * 20){
contractBalance = swapTokensAtAmount * 20;
}
if(tokensForTaxMem.tokensForLP > 0){
uint256 lpTokens = contractBalance * tokensForTaxMem.tokensForLP / totalTokensToSwap;
super._transfer(address(this), pair, lpTokens);
try ILpPair(pair).sync(){} catch {}
contractBalance -= lpTokens;
totalTokensToSwap -= tokensForTaxMem.tokensForLP;
}
if(contractBalance > 0){
swapTokensForETH(contractBalance);
uint256 ethBalance = address(this).balance;
bool success;
if(tokensForTaxMem.tokensForDev > 0){
(success,) = devAddress.call{value: ethBalance * tokensForTaxMem.tokensForDev / totalTokensToSwap}("");
}
if(tokensForTaxMem.tokensForRevShare > 0){
(success,) = address(revShare).call{value: ethBalance * tokensForTaxMem.tokensForRevShare/ totalTokensToSwap}("");
}
ethBalance = address(this).balance;
if(ethBalance > 0){
(success,) = mktingAddress.call{value: ethBalance}("");
}
}
tokensForTaxMem.tokensForLP = 0;
tokensForTaxMem.tokensForMkting = 0;
tokensForTaxMem.tokensForDev = 0;
tokensForTaxMem.tokensForRevShare = 0;
tokensForTax = tokensForTaxMem;
}
// owner functions
function setExcludedFromFee(address _address, bool _isExcluded) external onlyOwner {
require(_address != address(0), "Zero Address");
require(_address != address(this), "Cannot unexcluded contract");
excludedFromFees[_address] = _isExcluded;
emit SetExcludedFromFees(_address, _isExcluded);
}
function setExcludedFromLimit(address _address, bool _isExcluded) external onlyOwner {
require(_address != address(0), "Zero Address");
if(!_isExcluded){
require(_address != pair, "Cannot remove pair");
}
excludedFromLimits[_address] = _isExcluded;
emit SetExcludedFromLimits(_address, _isExcluded);
}
function changeTransactionLimit(uint128 newNumInTokens) external onlyOwner {
require(newNumInTokens >= (totalSupply() * 1 / 1000)/(10**decimals()), "Too low");
txLimits.transactionLimit = uint128(newNumInTokens * (10**decimals()));
emit UpdatedTransactionLimit(txLimits.transactionLimit);
}
function changeWalletLimit(uint128 newNumInTokens) external onlyOwner {
require(newNumInTokens >= (totalSupply() * 1 / 1000)/(10**decimals()), "Too low");
txLimits.walletLimit = uint128(newNumInTokens * (10**decimals()));
emit UpdatedWalletLimit(txLimits.walletLimit);
}
function changeSwapTokensAmount(uint256 newAmount) external onlyOwner {
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;
}
function changeSellTax(uint48 _mktingTax, uint48 _lpTax, uint48 _devTax, uint48 _revShareTax) external onlyOwner {
Tax memory taxes;
taxes.mktingTax = _mktingTax;
taxes.lpTax = _lpTax;
taxes.devTax = _devTax;
taxes.revShareTax = _revShareTax;
taxes.totalTax = _mktingTax + _lpTax + _devTax + _revShareTax;
require(taxes.totalTax <= 1000, "Keep tax below 10%");
emit SellTaxUpdated(taxes.totalTax);
sellTax = taxes;
}
function changeBuyTax(uint48 _mktingTax, uint48 _lpTax, uint48 _devTax, uint48 _revShareTax) external onlyOwner {
Tax memory taxes;
taxes.mktingTax = _mktingTax;
taxes.lpTax = _lpTax;
taxes.devTax = _devTax;
taxes.revShareTax = _revShareTax;
taxes.totalTax = _mktingTax + _lpTax + _devTax + _revShareTax;
require(taxes.totalTax <= 1000, "Keep tax below 10%");
emit BuyTaxUpdated(taxes.totalTax);
buyTax = taxes;
}
function setLaunched() external onlyOwner {
require(!launched, "Trading already live");
launched = true;
}
function removeTxLimits() external onlyOwner {
txLimitsActive = false;
TxLimits memory _txLimits;
uint256 supply = totalSupply();
_txLimits.transactionLimit = uint128(supply);
_txLimits.walletLimit = uint128(supply);
txLimits = _txLimits;
emit RemovedLimits();
}
function updateSandwichBlockerEnabled(bool _enabled) external onlyOwner {
antiSandwichEnabled = _enabled;
}
function updateMktingAddress(address _address) external onlyOwner {
require(_address != address(0), "zero address");
mktingAddress = _address;
}
function updateDevAddress(address _address) external onlyOwner {
require(_address != address(0), "zero address");
devAddress = _address;
}
receive() payable external {}
// dividend functions
function claim() external {
revShare.processAccount(payable(msg.sender), false);
}
function getTotalDividendsDistributed() external view returns (uint256) {
return revShare.totalDividendsDistributed();
}
function withdrawableDividendOf(address account) public view returns(uint256) {
return revShare.withdrawableDividendOf(account);
}
function dividendTokenBalanceOf(address account) public view returns (uint256) {
return revShare.holderBalance(account);
}
function getAccountDividendsInfo(address account)
external view returns (
address,
uint256,
uint256,
uint256) {
return revShare.getAccount(account);
}
function getNumberOfDividends() external view returns(uint256) {
return revShare.totalBalance();
}
function excludeFromDividends(address _wallet) external onlyOwner {
revShare.excludeFromDividends(_wallet);
}
function includeInDividends(address _wallet) external onlyOwner {
revShare.includeInDividends(_wallet);
}
function compound(uint256 minOutput) external {
uint256 amountEthForCompound = revShare.withdrawDividendOfUserForCompound(payable(msg.sender));
if(amountEthForCompound > 0){
buyBackTokens(amountEthForCompound, minOutput, msg.sender);
} else {
revert("No rewards");
}
}
function buyBackTokens(uint256 ethAmountInWei, uint256 minOut, address to) internal {
// generate the uniswap pair path of weth -> eth
address[] memory path = new address[](2);
path[0] = dexRouter.WETH();
path[1] = address(this);
// make the swap
dexRouter.swapExactETHForTokensSupportingFeeOnTransferTokens{value: ethAmountInWei}(
minOut,
path,
address(to),
block.timestamp
);
}
// helper views
function getCompoundOutputByEthAmount(uint256 rewardAmount) external view returns(uint256) {
address[] memory path = new address[](2);
path[0] = dexRouter.WETH();
path[1] = address(this);
uint256[] memory amounts = dexRouter.getAmountsOut(rewardAmount, path);
return amounts[1] - (amounts[1] * (buyTax.totalTax + 50) / FEE_DIVISOR);
}
function getCompoundOutputByWallet(address wallet) external view returns(uint256) {
uint256 rewardAmount = withdrawableDividendOf(wallet);
address[] memory path = new address[](2);
path[0] = dexRouter.WETH();
path[1] = address(this);
uint256[] memory amounts = dexRouter.getAmountsOut(rewardAmount, path);
return amounts[1] - (amounts[1] * (buyTax.totalTax + 50) / FEE_DIVISOR);
}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.8.0) (utils/cryptography/draft-EIP712.sol)
pragma solidity ^0.8.0;
// EIP-712 is Final as of 2022-08-11. This file is deprecated.
import "./EIP712.sol";
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (utils/cryptography/EIP712.sol)
pragma solidity ^0.8.20;
import {MessageHashUtils} from "./MessageHashUtils.sol";
import {ShortStrings, ShortString} from "../ShortStrings.sol";
import {IERC5267} from "../../interfaces/IERC5267.sol";
/**
* @dev https://eips.ethereum.org/EIPS/eip-712[EIP 712] is a standard for hashing and signing of typed structured data.
*
* The encoding scheme specified in the EIP requires a domain separator and a hash of the typed structured data, whose
* encoding is very generic and therefore its implementation in Solidity is not feasible, thus this contract
* does not implement the encoding itself. Protocols need to implement the type-specific encoding they need in order to
* produce the hash of their typed data using a combination of `abi.encode` and `keccak256`.
*
* This contract implements the EIP 712 domain separator ({_domainSeparatorV4}) that is used as part of the encoding
* scheme, and the final step of the encoding to obtain the message digest that is then signed via ECDSA
* ({_hashTypedDataV4}).
*
* The implementation of the domain separator was designed to be as efficient as possible while still properly updating
* the chain id to protect against replay attacks on an eventual fork of the chain.
*
* NOTE: This contract implements the version of the encoding known as "v4", as implemented by the JSON RPC method
* https://docs.metamask.io/guide/signing-data.html[`eth_signTypedDataV4` in MetaMask].
*
* NOTE: In the upgradeable version of this contract, the cached values will correspond to the address, and the domain
* separator of the implementation contract. This will cause the {_domainSeparatorV4} function to always rebuild the
* separator from the immutable values, which is cheaper than accessing a cached version in cold storage.
*
* @custom:oz-upgrades-unsafe-allow state-variable-immutable
*/
abstract contract EIP712 is IERC5267 {
using ShortStrings for *;
bytes32 private constant TYPE_HASH =
keccak256("EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)");
// Cache the domain separator as an immutable value, but also store the chain id that it corresponds to, in order to
// invalidate the cached domain separator if the chain id changes.
bytes32 private immutable _cachedDomainSeparator;
uint256 private immutable _cachedChainId;
address private immutable _cachedThis;
bytes32 private immutable _hashedName;
bytes32 private immutable _hashedVersion;
ShortString private immutable _name;
ShortString private immutable _version;
string private _nameFallback;
string private _versionFallback;
/**
* @dev Initializes the domain separator and parameter caches.
*
* The meaning of `name` and `version` is specified in
* https://eips.ethereum.org/EIPS/eip-712#definition-of-domainseparator[EIP 712]:
*
* - `name`: the user readable name of the signing domain, i.e. the name of the DApp or the protocol.
* - `version`: the current major version of the signing domain.
*
* NOTE: These parameters cannot be changed except through a xref:learn::upgrading-smart-contracts.adoc[smart
* contract upgrade].
*/
constructor(string memory name, string memory version) {
_name = name.toShortStringWithFallback(_nameFallback);
_version = version.toShortStringWithFallback(_versionFallback);
_hashedName = keccak256(bytes(name));
_hashedVersion = keccak256(bytes(version));
_cachedChainId = block.chainid;
_cachedDomainSeparator = _buildDomainSeparator();
_cachedThis = address(this);
}
/**
* @dev Returns the domain separator for the current chain.
*/
function _domainSeparatorV4() internal view returns (bytes32) {
if (address(this) == _cachedThis && block.chainid == _cachedChainId) {
return _cachedDomainSeparator;
} else {
return _buildDomainSeparator();
}
}
function _buildDomainSeparator() private view returns (bytes32) {
return keccak256(abi.encode(TYPE_HASH, _hashedName, _hashedVersion, block.chainid, address(this)));
}
/**
* @dev Given an already https://eips.ethereum.org/EIPS/eip-712#definition-of-hashstruct[hashed struct], this
* function returns the hash of the fully encoded EIP712 message for this domain.
*
* This hash can be used together with {ECDSA-recover} to obtain the signer of a message. For example:
*
* ```solidity
* bytes32 digest = _hashTypedDataV4(keccak256(abi.encode(
* keccak256("Mail(address to,string contents)"),
* mailTo,
* keccak256(bytes(mailContents))
* )));
* address signer = ECDSA.recover(digest, signature);
* ```
*/
function _hashTypedDataV4(bytes32 structHash) internal view virtual returns (bytes32) {
return MessageHashUtils.toTypedDataHash(_domainSeparatorV4(), structHash);
}
/**
* @dev See {IERC-5267}.
*/
function eip712Domain()
public
view
virtual
returns (
bytes1 fields,
string memory name,
string memory version,
uint256 chainId,
address verifyingContract,
bytes32 salt,
uint256[] memory extensions
)
{
return (
hex"0f", // 01111
_EIP712Name(),
_EIP712Version(),
block.chainid,
address(this),
bytes32(0),
new uint256[](0)
);
}
/**
* @dev The name parameter for the EIP712 domain.
*
* NOTE: By default this function reads _name which is an immutable value.
* It only reads from storage if necessary (in case the value is too large to fit in a ShortString).
*/
// solhint-disable-next-line func-name-mixedcase
function _EIP712Name() internal view returns (string memory) {
return _name.toStringWithFallback(_nameFallback);
}
/**
* @dev The version parameter for the EIP712 domain.
*
* NOTE: By default this function reads _version which is an immutable value.
* It only reads from storage if necessary (in case the value is too large to fit in a ShortString).
*/
// solhint-disable-next-line func-name-mixedcase
function _EIP712Version() internal view returns (string memory) {
return _version.toStringWithFallback(_versionFallback);
}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (interfaces/IERC5267.sol)
pragma solidity ^0.8.20;
interface IERC5267 {
/**
* @dev MAY be emitted to signal that the domain could have changed.
*/
event EIP712DomainChanged();
/**
* @dev returns the fields and values that describe the domain separator used by this contract for EIP-712
* signature.
*/
function eip712Domain()
external
view
returns (
bytes1 fields,
string memory name,
string memory version,
uint256 chainId,
address verifyingContract,
bytes32 salt,
uint256[] memory extensions
);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (utils/ShortStrings.sol)
pragma solidity ^0.8.20;
import {StorageSlot} from "./StorageSlot.sol";
// | string | 0xAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA |
// | length | 0x BB |
type ShortString is bytes32;
/**
* @dev This library provides functions to convert short memory strings
* into a `ShortString` type that can be used as an immutable variable.
*
* Strings of arbitrary length can be optimized using this library if
* they are short enough (up to 31 bytes) by packing them with their
* length (1 byte) in a single EVM word (32 bytes). Additionally, a
* fallback mechanism can be used for every other case.
*
* Usage example:
*
* ```solidity
* contract Named {
* using ShortStrings for *;
*
* ShortString private immutable _name;
* string private _nameFallback;
*
* constructor(string memory contractName) {
* _name = contractName.toShortStringWithFallback(_nameFallback);
* }
*
* function name() external view returns (string memory) {
* return _name.toStringWithFallback(_nameFallback);
* }
* }
* ```
*/
library ShortStrings {
// Used as an identifier for strings longer than 31 bytes.
bytes32 private constant FALLBACK_SENTINEL = 0x00000000000000000000000000000000000000000000000000000000000000FF;
error StringTooLong(string str);
error InvalidShortString();
/**
* @dev Encode a string of at most 31 chars into a `ShortString`.
*
* This will trigger a `StringTooLong` error is the input string is too long.
*/
function toShortString(string memory str) internal pure returns (ShortString) {
bytes memory bstr = bytes(str);
if (bstr.length > 31) {
revert StringTooLong(str);
}
return ShortString.wrap(bytes32(uint256(bytes32(bstr)) | bstr.length));
}
/**
* @dev Decode a `ShortString` back to a "normal" string.
*/
function toString(ShortString sstr) internal pure returns (string memory) {
uint256 len = byteLength(sstr);
// using `new string(len)` would work locally but is not memory safe.
string memory str = new string(32);
/// @solidity memory-safe-assembly
assembly {
mstore(str, len)
mstore(add(str, 0x20), sstr)
}
return str;
}
/**
* @dev Return the length of a `ShortString`.
*/
function byteLength(ShortString sstr) internal pure returns (uint256) {
uint256 result = uint256(ShortString.unwrap(sstr)) & 0xFF;
if (result > 31) {
revert InvalidShortString();
}
return result;
}
/**
* @dev Encode a string into a `ShortString`, or write it to storage if it is too long.
*/
function toShortStringWithFallback(string memory value, string storage store) internal returns (ShortString) {
if (bytes(value).length < 32) {
return toShortString(value);
} else {
StorageSlot.getStringSlot(store).value = value;
return ShortString.wrap(FALLBACK_SENTINEL);
}
}
/**
* @dev Decode a string that was encoded to `ShortString` or written to storage using {setWithFallback}.
*/
function toStringWithFallback(ShortString value, string storage store) internal pure returns (string memory) {
if (ShortString.unwrap(value) != FALLBACK_SENTINEL) {
return toString(value);
} else {
return store;
}
}
/**
* @dev Return the length of a string that was encoded to `ShortString` or written to storage using
* {setWithFallback}.
*
* WARNING: This will return the "byte length" of the string. This may not reflect the actual length in terms of
* actual characters as the UTF-8 encoding of a single character can span over multiple bytes.
*/
function byteLengthWithFallback(ShortString value, string storage store) internal view returns (uint256) {
if (ShortString.unwrap(value) != FALLBACK_SENTINEL) {
return byteLength(value);
} else {
return bytes(store).length;
}
}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (utils/cryptography/MessageHashUtils.sol)
pragma solidity ^0.8.20;
import {Strings} from "../Strings.sol";
/**
* @dev Signature message hash utilities for producing digests to be consumed by {ECDSA} recovery or signing.
*
* The library provides methods for generating a hash of a message that conforms to the
* https://eips.ethereum.org/EIPS/eip-191[EIP 191] and https://eips.ethereum.org/EIPS/eip-712[EIP 712]
* specifications.
*/
library MessageHashUtils {
/**
* @dev Returns the keccak256 digest of an EIP-191 signed data with version
* `0x45` (`personal_sign` messages).
*
* The digest is calculated by prefixing a bytes32 `messageHash` with
* `"\x19Ethereum Signed Message:\n32"` and hashing the result. It corresponds with the
* hash signed when using the https://eth.wiki/json-rpc/API#eth_sign[`eth_sign`] JSON-RPC method.
*
* NOTE: The `messageHash` parameter is intended to be the result of hashing a raw message with
* keccak256, although any bytes32 value can be safely used because the final digest will
* be re-hashed.
*
* See {ECDSA-recover}.
*/
function toEthSignedMessageHash(bytes32 messageHash) internal pure returns (bytes32 digest) {
/// @solidity memory-safe-assembly
assembly {
mstore(0x00, "\x19Ethereum Signed Message:\n32") // 32 is the bytes-length of messageHash
mstore(0x1c, messageHash) // 0x1c (28) is the length of the prefix
digest := keccak256(0x00, 0x3c) // 0x3c is the length of the prefix (0x1c) + messageHash (0x20)
}
}
/**
* @dev Returns the keccak256 digest of an EIP-191 signed data with version
* `0x45` (`personal_sign` messages).
*
* The digest is calculated by prefixing an arbitrary `message` with
* `"\x19Ethereum Signed Message:\n" + len(message)` and hashing the result. It corresponds with the
* hash signed when using the https://eth.wiki/json-rpc/API#eth_sign[`eth_sign`] JSON-RPC method.
*
* See {ECDSA-recover}.
*/
function toEthSignedMessageHash(bytes memory message) internal pure returns (bytes32) {
return
keccak256(bytes.concat("\x19Ethereum Signed Message:\n", bytes(Strings.toString(message.length)), message));
}
/**
* @dev Returns the keccak256 digest of an EIP-191 signed data with version
* `0x00` (data with intended validator).
*
* The digest is calculated by prefixing an arbitrary `data` with `"\x19\x00"` and the intended
* `validator` address. Then hashing the result.
*
* See {ECDSA-recover}.
*/
function toDataWithIntendedValidatorHash(address validator, bytes memory data) internal pure returns (bytes32) {
return keccak256(abi.encodePacked(hex"19_00", validator, data));
}
/**
* @dev Returns the keccak256 digest of an EIP-712 typed data (EIP-191 version `0x01`).
*
* The digest is calculated from a `domainSeparator` and a `structHash`, by prefixing them with
* `\x19\x01` and hashing the result. It corresponds to the hash signed by the
* https://eips.ethereum.org/EIPS/eip-712[`eth_signTypedData`] JSON-RPC method as part of EIP-712.
*
* See {ECDSA-recover}.
*/
function toTypedDataHash(bytes32 domainSeparator, bytes32 structHash) internal pure returns (bytes32 digest) {
/// @solidity memory-safe-assembly
assembly {
let ptr := mload(0x40)
mstore(ptr, hex"19_01")
mstore(add(ptr, 0x02), domainSeparator)
mstore(add(ptr, 0x22), structHash)
digest := keccak256(ptr, 0x42)
}
}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (utils/Strings.sol)
pragma solidity ^0.8.20;
import {Math} from "./math/Math.sol";
import {SignedMath} from "./math/SignedMath.sol";
/**
* @dev String operations.
*/
library Strings {
bytes16 private constant HEX_DIGITS = "0123456789abcdef";
uint8 private constant ADDRESS_LENGTH = 20;
/**
* @dev The `value` string doesn't fit in the specified `length`.
*/
error StringsInsufficientHexLength(uint256 value, uint256 length);
/**
* @dev Converts a `uint256` to its ASCII `string` decimal representation.
*/
function toString(uint256 value) internal pure returns (string memory) {
unchecked {
uint256 length = Math.log10(value) + 1;
string memory buffer = new string(length);
uint256 ptr;
/// @solidity memory-safe-assembly
assembly {
ptr := add(buffer, add(32, length))
}
while (true) {
ptr--;
/// @solidity memory-safe-assembly
assembly {
mstore8(ptr, byte(mod(value, 10), HEX_DIGITS))
}
value /= 10;
if (value == 0) break;
}
return buffer;
}
}
/**
* @dev Converts a `int256` to its ASCII `string` decimal representation.
*/
function toStringSigned(int256 value) internal pure returns (string memory) {
return string.concat(value < 0 ? "-" : "", toString(SignedMath.abs(value)));
}
/**
* @dev Converts a `uint256` to its ASCII `string` hexadecimal representation.
*/
function toHexString(uint256 value) internal pure returns (string memory) {
unchecked {
return toHexString(value, Math.log256(value) + 1);
}
}
/**
* @dev Converts a `uint256` to its ASCII `string` hexadecimal representation with fixed length.
*/
function toHexString(uint256 value, uint256 length) internal pure returns (string memory) {
uint256 localValue = value;
bytes memory buffer = new bytes(2 * length + 2);
buffer[0] = "0";
buffer[1] = "x";
for (uint256 i = 2 * length + 1; i > 1; --i) {
buffer[i] = HEX_DIGITS[localValue & 0xf];
localValue >>= 4;
}
if (localValue != 0) {
revert StringsInsufficientHexLength(value, length);
}
return string(buffer);
}
/**
* @dev Converts an `address` with fixed length of 20 bytes to its not checksummed ASCII `string` hexadecimal
* representation.
*/
function toHexString(address addr) internal pure returns (string memory) {
return toHexString(uint256(uint160(addr)), ADDRESS_LENGTH);
}
/**
* @dev Returns true if the two strings are equal.
*/
function equal(string memory a, string memory b) internal pure returns (bool) {
return bytes(a).length == bytes(b).length && keccak256(bytes(a)) == keccak256(bytes(b));
}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (utils/StorageSlot.sol)
// This file was procedurally generated from scripts/generate/templates/StorageSlot.js.
pragma solidity ^0.8.20;
/**
* @dev Library for reading and writing primitive types to specific storage slots.
*
* Storage slots are often used to avoid storage conflict when dealing with upgradeable contracts.
* This library helps with reading and writing to such slots without the need for inline assembly.
*
* The functions in this library return Slot structs that contain a `value` member that can be used to read or write.
*
* Example usage to set ERC1967 implementation slot:
* ```solidity
* contract ERC1967 {
* bytes32 internal constant _IMPLEMENTATION_SLOT = 0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc;
*
* function _getImplementation() internal view returns (address) {
* return StorageSlot.getAddressSlot(_IMPLEMENTATION_SLOT).value;
* }
*
* function _setImplementation(address newImplementation) internal {
* require(newImplementation.code.length > 0);
* StorageSlot.getAddressSlot(_IMPLEMENTATION_SLOT).value = newImplementation;
* }
* }
* ```
*/
library StorageSlot {
struct AddressSlot {
address value;
}
struct BooleanSlot {
bool value;
}
struct Bytes32Slot {
bytes32 value;
}
struct Uint256Slot {
uint256 value;
}
struct StringSlot {
string value;
}
struct BytesSlot {
bytes value;
}
/**
* @dev Returns an `AddressSlot` with member `value` located at `slot`.
*/
function getAddressSlot(bytes32 slot) internal pure returns (AddressSlot storage r) {
/// @solidity memory-safe-assembly
assembly {
r.slot := slot
}
}
/**
* @dev Returns an `BooleanSlot` with member `value` located at `slot`.
*/
function getBooleanSlot(bytes32 slot) internal pure returns (BooleanSlot storage r) {
/// @solidity memory-safe-assembly
assembly {
r.slot := slot
}
}
/**
* @dev Returns an `Bytes32Slot` with member `value` located at `slot`.
*/
function getBytes32Slot(bytes32 slot) internal pure returns (Bytes32Slot storage r) {
/// @solidity memory-safe-assembly
assembly {
r.slot := slot
}
}
/**
* @dev Returns an `Uint256Slot` with member `value` located at `slot`.
*/
function getUint256Slot(bytes32 slot) internal pure returns (Uint256Slot storage r) {
/// @solidity memory-safe-assembly
assembly {
r.slot := slot
}
}
/**
* @dev Returns an `StringSlot` with member `value` located at `slot`.
*/
function getStringSlot(bytes32 slot) internal pure returns (StringSlot storage r) {
/// @solidity memory-safe-assembly
assembly {
r.slot := slot
}
}
/**
* @dev Returns an `StringSlot` representation of the string storage pointer `store`.
*/
function getStringSlot(string storage store) internal pure returns (StringSlot storage r) {
/// @solidity memory-safe-assembly
assembly {
r.slot := store.slot
}
}
/**
* @dev Returns an `BytesSlot` with member `value` located at `slot`.
*/
function getBytesSlot(bytes32 slot) internal pure returns (BytesSlot storage r) {
/// @solidity memory-safe-assembly
assembly {
r.slot := slot
}
}
/**
* @dev Returns an `BytesSlot` representation of the bytes storage pointer `store`.
*/
function getBytesSlot(bytes storage store) internal pure returns (BytesSlot storage r) {
/// @solidity memory-safe-assembly
assembly {
r.slot := store.slot
}
}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (utils/math/SignedMath.sol)
pragma solidity ^0.8.20;
/**
* @dev Standard signed math utilities missing in the Solidity language.
*/
library SignedMath {
/**
* @dev Returns the largest of two signed numbers.
*/
function max(int256 a, int256 b) internal pure returns (int256) {
return a > b ? a : b;
}
/**
* @dev Returns the smallest of two signed numbers.
*/
function min(int256 a, int256 b) internal pure returns (int256) {
return a < b ? a : b;
}
/**
* @dev Returns the average of two signed numbers without overflow.
* The result is rounded towards zero.
*/
function average(int256 a, int256 b) internal pure returns (int256) {
// Formula from the book "Hacker's Delight"
int256 x = (a & b) + ((a ^ b) >> 1);
return x + (int256(uint256(x) >> 255) & (a ^ b));
}
/**
* @dev Returns the absolute unsigned value of a signed value.
*/
function abs(int256 n) internal pure returns (uint256) {
unchecked {
// must be unchecked in order to support `n = type(int256).min`
return uint256(n >= 0 ? n : -n);
}
}
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (utils/math/Math.sol)
pragma solidity ^0.8.20;
/**
* @dev Standard math utilities missing in the Solidity language.
*/
library Math {
/**
* @dev Muldiv operation overflow.
*/
error MathOverflowedMulDiv();
enum Rounding {
Floor, // Toward negative infinity
Ceil, // Toward positive infinity
Trunc, // Toward zero
Expand // Away from zero
}
/**
* @dev Returns the addition of two unsigned integers, with an overflow flag.
*/
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 subtraction of two unsigned integers, with an overflow flag.
*/
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.
*/
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.
*/
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.
*/
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 largest of two numbers.
*/
function max(uint256 a, uint256 b) internal pure returns (uint256) {
return a > b ? a : b;
}
/**
* @dev Returns the smallest of two numbers.
*/
function min(uint256 a, uint256 b) internal pure returns (uint256) {
return a < b ? a : b;
}
/**
* @dev Returns the average of two numbers. The result is rounded towards
* zero.
*/
function average(uint256 a, uint256 b) internal pure returns (uint256) {
// (a + b) / 2 can overflow.
return (a & b) + (a ^ b) / 2;
}
/**
* @dev Returns the ceiling of the division of two numbers.
*
* This differs from standard division with `/` in that it rounds towards infinity instead
* of rounding towards zero.
*/
function ceilDiv(uint256 a, uint256 b) internal pure returns (uint256) {
if (b == 0) {
// Guarantee the same behavior as in a regular Solidity division.
return a / b;
}
// (a + b - 1) / b can overflow on addition, so we distribute.
return a == 0 ? 0 : (a - 1) / b + 1;
}
/**
* @notice Calculates floor(x * y / denominator) with full precision. Throws if result overflows a uint256 or
* denominator == 0.
* @dev Original credit to Remco Bloemen under MIT license (https://xn--2-umb.com/21/muldiv) with further edits by
* Uniswap Labs also under MIT license.
*/
function mulDiv(uint256 x, uint256 y, uint256 denominator) internal pure returns (uint256 result) {
unchecked {
// 512-bit multiply [prod1 prod0] = x * y. Compute the product mod 2^256 and mod 2^256 - 1, then use
// use the Chinese Remainder Theorem to reconstruct the 512 bit result. The result is stored in two 256
// variables such that product = prod1 * 2^256 + prod0.
uint256 prod0 = x * y; // Least significant 256 bits of the product
uint256 prod1; // Most significant 256 bits of the product
assembly {
let mm := mulmod(x, y, not(0))
prod1 := sub(sub(mm, prod0), lt(mm, prod0))
}
// Handle non-overflow cases, 256 by 256 division.
if (prod1 == 0) {
// Solidity will revert if denominator == 0, unlike the div opcode on its own.
// The surrounding unchecked block does not change this fact.
// See https://docs.soliditylang.org/en/latest/control-structures.html#checked-or-unchecked-arithmetic.
return prod0 / denominator;
}
// Make sure the result is less than 2^256. Also prevents denominator == 0.
if (denominator <= prod1) {
revert MathOverflowedMulDiv();
}
///////////////////////////////////////////////
// 512 by 256 division.
///////////////////////////////////////////////
// Make division exact by subtracting the remainder from [prod1 prod0].
uint256 remainder;
assembly {
// Compute remainder using mulmod.
remainder := mulmod(x, y, denominator)
// Subtract 256 bit number from 512 bit number.
prod1 := sub(prod1, gt(remainder, prod0))
prod0 := sub(prod0, remainder)
}
// Factor powers of two out of denominator and compute largest power of two divisor of denominator.
// Always >= 1. See https://cs.stackexchange.com/q/138556/92363.
uint256 twos = denominator & (0 - denominator);
assembly {
// Divide denominator by twos.
denominator := div(denominator, twos)
// Divide [prod1 prod0] by twos.
prod0 := div(prod0, twos)
// Flip twos such that it is 2^256 / twos. If twos is zero, then it becomes one.
twos := add(div(sub(0, twos), twos), 1)
}
// Shift in bits from prod1 into prod0.
prod0 |= prod1 * twos;
// Invert denominator mod 2^256. Now that denominator is an odd number, it has an inverse modulo 2^256 such
// that denominator * inv = 1 mod 2^256. Compute the inverse by starting with a seed that is correct for
// four bits. That is, denominator * inv = 1 mod 2^4.
uint256 inverse = (3 * denominator) ^ 2;
// Use the Newton-Raphson iteration to improve the precision. Thanks to Hensel's lifting lemma, this also
// works in modular arithmetic, doubling the correct bits in each step.
inverse *= 2 - denominator * inverse; // inverse mod 2^8
inverse *= 2 - denominator * inverse; // inverse mod 2^16
inverse *= 2 - denominator * inverse; // inverse mod 2^32
inverse *= 2 - denominator * inverse; // inverse mod 2^64
inverse *= 2 - denominator * inverse; // inverse mod 2^128
inverse *= 2 - denominator * inverse; // inverse mod 2^256
// Because the division is now exact we can divide by multiplying with the modular inverse of denominator.
// This will give us the correct result modulo 2^256. Since the preconditions guarantee that the outcome is
// less than 2^256, this is the final result. We don't need to compute the high bits of the result and prod1
// is no longer required.
result = prod0 * inverse;
return result;
}
}
/**
* @notice Calculates x * y / denominator with full precision, following the selected rounding direction.
*/
function mulDiv(uint256 x, uint256 y, uint256 denominator, Rounding rounding) internal pure returns (uint256) {
uint256 result = mulDiv(x, y, denominator);
if (unsignedRoundsUp(rounding) && mulmod(x, y, denominator) > 0) {
result += 1;
}
return result;
}
/**
* @dev Returns the square root of a number. If the number is not a perfect square, the value is rounded
* towards zero.
*
* Inspired by Henry S. Warren, Jr.'s "Hacker's Delight" (Chapter 11).
*/
function sqrt(uint256 a) internal pure returns (uint256) {
if (a == 0) {
return 0;
}
// For our first guess, we get the biggest power of 2 which is smaller than the square root of the target.
//
// We know that the "msb" (most significant bit) of our target number `a` is a power of 2 such that we have
// `msb(a) <= a < 2*msb(a)`. This value can be written `msb(a)=2**k` with `k=log2(a)`.
//
// This can be rewritten `2**log2(a) <= a < 2**(log2(a) + 1)`
// → `sqrt(2**k) <= sqrt(a) < sqrt(2**(k+1))`
// → `2**(k/2) <= sqrt(a) < 2**((k+1)/2) <= 2**(k/2 + 1)`
//
// Consequently, `2**(log2(a) / 2)` is a good first approximation of `sqrt(a)` with at least 1 correct bit.
uint256 result = 1 << (log2(a) >> 1);
// At this point `result` is an estimation with one bit of precision. We know the true value is a uint128,
// since it is the square root of a uint256. Newton's method converges quadratically (precision doubles at
// every iteration). We thus need at most 7 iteration to turn our partial result with one bit of precision
// into the expected uint128 result.
unchecked {
result = (result + a / result) >> 1;
result = (result + a / result) >> 1;
result = (result + a / result) >> 1;
result = (result + a / result) >> 1;
result = (result + a / result) >> 1;
result = (result + a / result) >> 1;
result = (result + a / result) >> 1;
return min(result, a / result);
}
}
/**
* @notice Calculates sqrt(a), following the selected rounding direction.
*/
function sqrt(uint256 a, Rounding rounding) internal pure returns (uint256) {
unchecked {
uint256 result = sqrt(a);
return result + (unsignedRoundsUp(rounding) && result * result < a ? 1 : 0);
}
}
/**
* @dev Return the log in base 2 of a positive value rounded towards zero.
* Returns 0 if given 0.
*/
function log2(uint256 value) internal pure returns (uint256) {
uint256 result = 0;
unchecked {
if (value >> 128 > 0) {
value >>= 128;
result += 128;
}
if (value >> 64 > 0) {
value >>= 64;
result += 64;
}
if (value >> 32 > 0) {
value >>= 32;
result += 32;
}
if (value >> 16 > 0) {
value >>= 16;
result += 16;
}
if (value >> 8 > 0) {
value >>= 8;
result += 8;
}
if (value >> 4 > 0) {
value >>= 4;
result += 4;
}
if (value >> 2 > 0) {
value >>= 2;
result += 2;
}
if (value >> 1 > 0) {
result += 1;
}
}
return result;
}
/**
* @dev Return the log in base 2, following the selected rounding direction, of a positive value.
* Returns 0 if given 0.
*/
function log2(uint256 value, Rounding rounding) internal pure returns (uint256) {
unchecked {
uint256 result = log2(value);
return result + (unsignedRoundsUp(rounding) && 1 << result < value ? 1 : 0);
}
}
/**
* @dev Return the log in base 10 of a positive value rounded towards zero.
* Returns 0 if given 0.
*/
function log10(uint256 value) internal pure returns (uint256) {
uint256 result = 0;
unchecked {
if (value >= 10 ** 64) {
value /= 10 ** 64;
result += 64;
}
if (value >= 10 ** 32) {
value /= 10 ** 32;
result += 32;
}
if (value >= 10 ** 16) {
value /= 10 ** 16;
result += 16;
}
if (value >= 10 ** 8) {
value /= 10 ** 8;
result += 8;
}
if (value >= 10 ** 4) {
value /= 10 ** 4;
result += 4;
}
if (value >= 10 ** 2) {
value /= 10 ** 2;
result += 2;
}
if (value >= 10 ** 1) {
result += 1;
}
}
return result;
}
/**
* @dev Return the log in base 10, following the selected rounding direction, of a positive value.
* Returns 0 if given 0.
*/
function log10(uint256 value, Rounding rounding) internal pure returns (uint256) {
unchecked {
uint256 result = log10(value);
return result + (unsignedRoundsUp(rounding) && 10 ** result < value ? 1 : 0);
}
}
/**
* @dev Return the log in base 256 of a positive value rounded towards zero.
* Returns 0 if given 0.
*
* Adding one to the result gives the number of pairs of hex symbols needed to represent `value` as a hex string.
*/
function log256(uint256 value) internal pure returns (uint256) {
uint256 result = 0;
unchecked {
if (value >> 128 > 0) {
value >>= 128;
result += 16;
}
if (value >> 64 > 0) {
value >>= 64;
result += 8;
}
if (value >> 32 > 0) {
value >>= 32;
result += 4;
}
if (value >> 16 > 0) {
value >>= 16;
result += 2;
}
if (value >> 8 > 0) {
result += 1;
}
}
return result;
}
/**
* @dev Return the log in base 256, following the selected rounding direction, of a positive value.
* Returns 0 if given 0.
*/
function log256(uint256 value, Rounding rounding) internal pure returns (uint256) {
unchecked {
uint256 result = log256(value);
return result + (unsignedRoundsUp(rounding) && 1 << (result << 3) < value ? 1 : 0);
}
}
/**
* @dev Returns whether a provided rounding mode is considered rounding up for unsigned integers.
*/
function unsignedRoundsUp(Rounding rounding) internal pure returns (bool) {
return uint8(rounding) % 2 == 1;
}
}