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// This contract is part of Zellic’s smart contract dataset, which is a collection of publicly available contract code gathered as of March 2023. |
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/**
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* ._...._.
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* \ .*. / .::o:::::.
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* (\o/) .:::'''':o:.
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* >*< `:}_>()<_{:'
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* >0<@< @ `'//\\'` @
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* >>>@<<* @
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* >@>*<0<<< .__
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* >*>>@<<<@<< [_________________________]
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* >@>>0<<<*<<@< |=_- .-/\ /\ /\ /\--. =_-|
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* >*>>0<<@<<<@<<< |-_= | \ \ \ \ \ \\-|-_=-|
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* >@>>*<<@<>*<<0<*< |_=-=| / // // // / |_=-_|
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* \*\ >0>>*<<@<>0><<*<@<< |=_- | `-'`-'`-'`-' |=_=-|
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* .___\U//__. >*>>@><0<<*>>@><*<0<< | =_-| o o |_==_|
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* \ | | \ | >@>>0<*<<0>>@<<0<<<*<@< |=_- | ! ( ! |=-_=|
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* \| | _(UU)_ >((*))_>0><*<0><@<<<0<*<|-,-=| ! ). ! |-_-=|
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* \ \| || / //||.*.*.*.|>>@<<*<<@>><0<<|=_,=| ! __(:')__ ! |=_==|
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* \_|_|&&_// ||*.*.*.*|_\db//_ (\_/)-| /^\=^=^^=^=/^\| _=_|
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* ""|'.'.'.|~~|.*.*.*| | =('Y')=|=_,//.------------.\\_,_|
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* |'.'.'.| |^^^^^^|______| ( ~~~ )|_,_/(((((((())))))))\_,_|
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* ~~~~~~~ "" `------' `w---w'|_____`------------'_____|
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* ________________________________________________________________
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*
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*/
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// SPDX-License-Identifier: MIT
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pragma solidity 0.8.8;
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pragma experimental ABIEncoderV2;
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/**
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* @dev Provides information about the current execution context, including the
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* sender of the transaction and its data. While these are generally available
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* via msg.sender and msg.data, they should not be accessed in such a direct
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* manner, since when dealing with meta-transactions the account sending and
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* paying for execution may not be the actual sender (as far as an application
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* is concerned).
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*
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* This contract is only required for intermediate, library-like contracts.
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*/
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abstract contract Context {
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function _msgSender() internal view virtual returns (address) {
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return msg.sender;
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}
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function _msgData() internal view virtual returns (bytes calldata) {
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return msg.data;
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}
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}
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/**
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* @dev Contract module which provides a basic access control mechanism, where
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* there is an account (an owner) that can be granted exclusive access to
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* specific functions.
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*
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* By default, the owner account will be the one that deploys the contract. This
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* can later be changed with {transferOwnership}.
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*
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* This module is used through inheritance. It will make available the modifier
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* `onlyOwner`, which can be applied to your functions to restrict their use to
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* the owner.
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*/
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abstract contract Ownable is Context {
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address private _owner;
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event OwnershipTransferred(
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address indexed previousOwner,
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address indexed newOwner
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);
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/**
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* @dev Initializes the contract setting the deployer as the initial owner.
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*/
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constructor() {
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_transferOwnership(_msgSender());
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}
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/**
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* @dev Returns the address of the current owner.
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*/
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function owner() public view virtual returns (address) {
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return _owner;
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}
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/**
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* @dev Throws if called by any account other than the owner.
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*/
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modifier onlyOwner() {
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require(owner() == _msgSender(), "Ownable: caller is not the owner");
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_;
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}
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/**
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* @dev Leaves the contract without owner. It will not be possible to call
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* `onlyOwner` functions anymore. Can only be called by the current owner.
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*
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* NOTE: Renouncing ownership will leave the contract without an owner,
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* thereby removing any functionality that is only available to the owner.
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*/
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function renounceOwnership() public virtual onlyOwner {
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_transferOwnership(address(0));
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}
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/**
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* @dev Transfers ownership of the contract to a new account (`newOwner`).
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* Can only be called by the current owner.
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*/
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function transferOwnership(address newOwner) public virtual onlyOwner {
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require(
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newOwner != address(0),
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"Ownable: new owner is the zero address"
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);
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_transferOwnership(newOwner);
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}
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/**
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* @dev Transfers ownership of the contract to a new account (`newOwner`).
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* Internal function without access restriction.
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*/
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function _transferOwnership(address newOwner) internal virtual {
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address oldOwner = _owner;
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_owner = newOwner;
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emit OwnershipTransferred(oldOwner, newOwner);
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}
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}
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/**
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* @dev Interface of the ERC20 standard as defined in the EIP.
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*/
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interface IERC20 {
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/**
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* @dev Returns the amount of tokens in existence.
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*/
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function totalSupply() external view returns (uint256);
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/**
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* @dev Returns the amount of tokens owned by `account`.
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*/
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function balanceOf(address account) external view returns (uint256);
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/**
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* @dev Moves `amount` tokens from the caller's account to `recipient`.
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*
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* Returns a boolean value indicating whether the operation succeeded.
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*
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* Emits a {Transfer} event.
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*/
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function transfer(address recipient, uint256 amount)
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external
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returns (bool);
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/**
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* @dev Returns the remaining number of tokens that `spender` will be
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* allowed to spend on behalf of `owner` through {transferFrom}. This is
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* zero by default.
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*
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* This value changes when {approve} or {transferFrom} are called.
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*/
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function allowance(address owner, address spender)
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external
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view
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returns (uint256);
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/**
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* @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
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*
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* Returns a boolean value indicating whether the operation succeeded.
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*
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* IMPORTANT: Beware that changing an allowance with this method brings the risk
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* that someone may use both the old and the new allowance by unfortunate
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* transaction ordering. One possible solution to mitigate this race
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* condition is to first reduce the spender's allowance to 0 and set the
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* desired value afterwards:
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* https://github.com/ethereum/EIPs/issues/20
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*
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* Emits an {Approval} event.
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*/
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function approve(address spender, uint256 amount) external returns (bool);
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/**
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* @dev Moves `amount` tokens from `sender` to `recipient` using the
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* allowance mechanism. `amount` is then deducted from the caller's
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* allowance.
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*
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* Returns a boolean value indicating whether the operation succeeded.
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*
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* Emits a {Transfer} event.
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*/
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function transferFrom(
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address sender,
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address recipient,
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uint256 amount
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) external returns (bool);
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/**
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* @dev Emitted when `value` tokens are moved from one account (`from`) to
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* another (`to`).
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*
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* Note that `value` may be zero.
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*/
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event Transfer(address indexed from, address indexed to, uint256 value);
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/**
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* @dev Emitted when the allowance of a `spender` for an `owner` is set by
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* a call to {approve}. `value` is the new allowance.
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*/
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event Approval(
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address indexed owner,
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address indexed spender,
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uint256 value
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);
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}
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/**
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* @dev Interface for the optional metadata functions from the ERC20 standard.
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*
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* _Available since v4.1._
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*/
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interface IERC20Metadata is IERC20 {
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/**
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* @dev Returns the name of the token.
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*/
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function name() external view returns (string memory);
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/**
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* @dev Returns the symbol of the token.
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*/
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function symbol() external view returns (string memory);
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/**
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* @dev Returns the decimals places of the token.
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*/
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function decimals() external view returns (uint8);
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}
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/**
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* @dev Implementation of the {IERC20} interface.
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*
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* This implementation is agnostic to the way tokens are created. This means
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* that a supply mechanism has to be added in a derived contract using {_mint}.
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* For a generic mechanism see {ERC20PresetMinterPauser}.
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*
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* TIP: For a detailed writeup see our guide
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* https://forum.zeppelin.solutions/t/how-to-implement-erc20-supply-mechanisms/226[How
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* to implement supply mechanisms].
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*
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* We have followed general OpenZeppelin Contracts guidelines: functions revert
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* instead returning `false` on failure. This behavior is nonetheless
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* conventional and does not conflict with the expectations of ERC20
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* applications.
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*
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* Additionally, an {Approval} event is emitted on calls to {transferFrom}.
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* This allows applications to reconstruct the allowance for all accounts just
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* by listening to said events. Other implementations of the EIP may not emit
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* these events, as it isn't required by the specification.
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*
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* Finally, the non-standard {decreaseAllowance} and {increaseAllowance}
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* functions have been added to mitigate the well-known issues around setting
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* allowances. See {IERC20-approve}.
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*/
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contract ERC20 is Context, IERC20, IERC20Metadata {
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mapping(address => uint256) private _balances;
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mapping(address => mapping(address => uint256)) private _allowances;
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uint256 private _totalSupply;
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string private _name;
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string private _symbol;
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/**
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* @dev Sets the values for {name} and {symbol}.
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*
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* The default value of {decimals} is 18. To select a different value for
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* {decimals} you should overload it.
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*
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* All two of these values are immutable: they can only be set once during
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* construction.
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*/
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constructor(string memory name_, string memory symbol_) {
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_name = name_;
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_symbol = symbol_;
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}
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/**
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* @dev Returns the name of the token.
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*/
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function name() public view virtual override returns (string memory) {
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return _name;
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}
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/**
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* @dev Returns the symbol of the token, usually a shorter version of the
|
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* name.
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*/
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function symbol() public view virtual override returns (string memory) {
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return _symbol;
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}
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/**
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* @dev Returns the number of decimals used to get its user representation.
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* For example, if `decimals` equals `2`, a balance of `505` tokens should
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* be displayed to a user as `5.05` (`505 / 10 ** 2`).
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*
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* Tokens usually opt for a value of 18, imitating the relationship between
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* Ether and Wei. This is the value {ERC20} uses, unless this function is
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* overridden;
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*
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* NOTE: This information is only used for _display_ purposes: it in
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* no way affects any of the arithmetic of the contract, including
|
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* {IERC20-balanceOf} and {IERC20-transfer}.
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*/
|
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function decimals() public view virtual override returns (uint8) {
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return 18;
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}
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|
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/**
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* @dev See {IERC20-totalSupply}.
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*/
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function totalSupply() public view virtual override returns (uint256) {
|
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return _totalSupply;
|
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}
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|
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/**
|
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* @dev See {IERC20-balanceOf}.
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*/
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function balanceOf(address account)
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public
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view
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virtual
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override
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returns (uint256)
|
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{
|
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return _balances[account];
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}
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|
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/**
|
|
* @dev See {IERC20-transfer}.
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|
*
|
|
* Requirements:
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*
|
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* - `recipient` cannot be the zero address.
|
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* - the caller must have a balance of at least `amount`.
|
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*/
|
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function transfer(address recipient, uint256 amount)
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public
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virtual
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override
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returns (bool)
|
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{
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_transfer(_msgSender(), recipient, amount);
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return true;
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}
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|
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/**
|
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* @dev See {IERC20-allowance}.
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*/
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function allowance(address owner, address spender)
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public
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view
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virtual
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override
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returns (uint256)
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{
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return _allowances[owner][spender];
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}
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/**
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* @dev See {IERC20-approve}.
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*
|
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* Requirements:
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*
|
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* - `spender` cannot be the zero address.
|
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*/
|
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function approve(address spender, uint256 amount)
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public
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virtual
|
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override
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returns (bool)
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{
|
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_approve(_msgSender(), spender, amount);
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return true;
|
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}
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|
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/**
|
|
* @dev See {IERC20-transferFrom}.
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*
|
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* Emits an {Approval} event indicating the updated allowance. This is not
|
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* required by the EIP. See the note at the beginning of {ERC20}.
|
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*
|
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* Requirements:
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*
|
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* - `sender` and `recipient` cannot be the zero address.
|
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* - `sender` must have a balance of at least `amount`.
|
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* - the caller must have allowance for ``sender``'s tokens of at least
|
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* `amount`.
|
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*/
|
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function transferFrom(
|
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address sender,
|
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address recipient,
|
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uint256 amount
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) public virtual override returns (bool) {
|
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_transfer(sender, recipient, amount);
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|
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uint256 currentAllowance = _allowances[sender][_msgSender()];
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require(
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currentAllowance >= amount,
|
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"ERC20: transfer amount exceeds allowance"
|
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);
|
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unchecked {
|
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_approve(sender, _msgSender(), currentAllowance - amount);
|
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}
|
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|
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return true;
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}
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|
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/**
|
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* @dev Atomically increases the allowance granted to `spender` by the caller.
|
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*
|
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* This is an alternative to {approve} that can be used as a mitigation for
|
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* problems described in {IERC20-approve}.
|
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*
|
|
* Emits an {Approval} event indicating the updated allowance.
|
|
*
|
|
* Requirements:
|
|
*
|
|
* - `spender` cannot be the zero address.
|
|
*/
|
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function increaseAllowance(address spender, uint256 addedValue)
|
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public
|
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virtual
|
|
returns (bool)
|
|
{
|
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_approve(
|
|
_msgSender(),
|
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spender,
|
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_allowances[_msgSender()][spender] + addedValue
|
|
);
|
|
return true;
|
|
}
|
|
|
|
/**
|
|
* @dev Atomically decreases the allowance granted to `spender` by the caller.
|
|
*
|
|
* This is an alternative to {approve} that can be used as a mitigation for
|
|
* problems described in {IERC20-approve}.
|
|
*
|
|
* Emits an {Approval} event indicating the updated allowance.
|
|
*
|
|
* Requirements:
|
|
*
|
|
* - `spender` cannot be the zero address.
|
|
* - `spender` must have allowance for the caller of at least
|
|
* `subtractedValue`.
|
|
*/
|
|
function decreaseAllowance(address spender, uint256 subtractedValue)
|
|
public
|
|
virtual
|
|
returns (bool)
|
|
{
|
|
uint256 currentAllowance = _allowances[_msgSender()][spender];
|
|
require(
|
|
currentAllowance >= subtractedValue,
|
|
"ERC20: decreased allowance below zero"
|
|
);
|
|
unchecked {
|
|
_approve(_msgSender(), spender, currentAllowance - subtractedValue);
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
/**
|
|
* @dev Moves `amount` of tokens from `sender` to `recipient`.
|
|
*
|
|
* This internal function is equivalent to {transfer}, and can be used to
|
|
* e.g. implement automatic token fees, slashing mechanisms, etc.
|
|
*
|
|
* Emits a {Transfer} event.
|
|
*
|
|
* Requirements:
|
|
*
|
|
* - `sender` cannot be the zero address.
|
|
* - `recipient` cannot be the zero address.
|
|
* - `sender` must have a balance of at least `amount`.
|
|
*/
|
|
function _transfer(
|
|
address sender,
|
|
address recipient,
|
|
uint256 amount
|
|
) internal virtual {
|
|
require(sender != address(0), "ERC20: transfer from the zero address");
|
|
require(recipient != address(0), "ERC20: transfer to the zero address");
|
|
|
|
_beforeTokenTransfer(sender, recipient, amount);
|
|
|
|
uint256 senderBalance = _balances[sender];
|
|
require(
|
|
senderBalance >= amount,
|
|
"ERC20: transfer amount exceeds balance"
|
|
);
|
|
unchecked {
|
|
_balances[sender] = senderBalance - amount;
|
|
}
|
|
_balances[recipient] += amount;
|
|
|
|
emit Transfer(sender, recipient, amount);
|
|
|
|
_afterTokenTransfer(sender, recipient, amount);
|
|
}
|
|
|
|
/** @dev Creates `amount` tokens and assigns them to `account`, increasing
|
|
* the total supply.
|
|
*
|
|
* Emits a {Transfer} event with `from` set to the zero address.
|
|
*
|
|
* Requirements:
|
|
*
|
|
* - `account` cannot be the zero address.
|
|
*/
|
|
function _mint(address account, uint256 amount) internal virtual {
|
|
require(account != address(0), "ERC20: mint to the zero address");
|
|
|
|
_beforeTokenTransfer(address(0), account, amount);
|
|
|
|
_totalSupply += amount;
|
|
_balances[account] += amount;
|
|
emit Transfer(address(0), account, amount);
|
|
|
|
_afterTokenTransfer(address(0), account, amount);
|
|
}
|
|
|
|
/**
|
|
* @dev Destroys `amount` tokens from `account`, reducing the
|
|
* total supply.
|
|
*
|
|
* Emits a {Transfer} event with `to` set to the zero address.
|
|
*
|
|
* Requirements:
|
|
*
|
|
* - `account` cannot be the zero address.
|
|
* - `account` must have at least `amount` tokens.
|
|
*/
|
|
function _burn(address account, uint256 amount) internal virtual {
|
|
require(account != address(0), "ERC20: burn from the zero address");
|
|
|
|
_beforeTokenTransfer(account, address(0), amount);
|
|
|
|
uint256 accountBalance = _balances[account];
|
|
require(accountBalance >= amount, "ERC20: burn amount exceeds balance");
|
|
unchecked {
|
|
_balances[account] = accountBalance - amount;
|
|
}
|
|
_totalSupply -= amount;
|
|
|
|
emit Transfer(account, address(0), amount);
|
|
|
|
_afterTokenTransfer(account, address(0), amount);
|
|
}
|
|
|
|
/**
|
|
* @dev Sets `amount` as the allowance of `spender` over the `owner` s tokens.
|
|
*
|
|
* This internal function is equivalent to `approve`, and can be used to
|
|
* e.g. set automatic allowances for certain subsystems, etc.
|
|
*
|
|
* Emits an {Approval} event.
|
|
*
|
|
* Requirements:
|
|
*
|
|
* - `owner` cannot be the zero address.
|
|
* - `spender` cannot be the zero address.
|
|
*/
|
|
function _approve(
|
|
address owner,
|
|
address spender,
|
|
uint256 amount
|
|
) internal virtual {
|
|
require(owner != address(0), "ERC20: approve from the zero address");
|
|
require(spender != address(0), "ERC20: approve to the zero address");
|
|
|
|
_allowances[owner][spender] = amount;
|
|
emit Approval(owner, spender, amount);
|
|
}
|
|
|
|
/**
|
|
* @dev Hook that is called before any transfer of tokens. This includes
|
|
* minting and burning.
|
|
*
|
|
* Calling conditions:
|
|
*
|
|
* - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
|
|
* will be transferred to `to`.
|
|
* - when `from` is zero, `amount` tokens will be minted for `to`.
|
|
* - when `to` is zero, `amount` of ``from``'s tokens will be burned.
|
|
* - `from` and `to` are never both zero.
|
|
*
|
|
* To learn more about hooks, head to xref:ROOT:extending-contracts.adoc
|
|
*/
|
|
function _beforeTokenTransfer(
|
|
address from,
|
|
address to,
|
|
uint256 amount
|
|
) internal virtual {}
|
|
|
|
/**
|
|
* @dev Hook that is called after any transfer of tokens. This includes
|
|
* minting and burning.
|
|
*
|
|
* Calling conditions:
|
|
*
|
|
* - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
|
|
* has been transferred to `to`.
|
|
* - when `from` is zero, `amount` tokens have been minted for `to`.
|
|
* - when `to` is zero, `amount` of ``from``'s tokens have been burned.
|
|
* - `from` and `to` are never both zero.
|
|
*
|
|
* To learn more about hooks, head to xref:ROOT:extending-contracts.adoc
|
|
*/
|
|
function _afterTokenTransfer(
|
|
address from,
|
|
address to,
|
|
uint256 amount
|
|
) internal virtual {}
|
|
}
|
|
|
|
/**
|
|
* @dev Wrappers over Solidity's arithmetic operations.
|
|
*
|
|
* NOTE: `SafeMath` is generally not needed starting with Solidity 0.8, since the compiler
|
|
* now has built in overflow checking.
|
|
*/
|
|
library SafeMath {
|
|
/**
|
|
* @dev Returns the addition of two unsigned integers, with an overflow flag.
|
|
*
|
|
* _Available since v3.4._
|
|
*/
|
|
function tryAdd(uint256 a, uint256 b)
|
|
internal
|
|
pure
|
|
returns (bool, uint256)
|
|
{
|
|
unchecked {
|
|
uint256 c = a + b;
|
|
if (c < a) return (false, 0);
|
|
return (true, c);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* @dev Returns the substraction of two unsigned integers, with an overflow flag.
|
|
*
|
|
* _Available since v3.4._
|
|
*/
|
|
function trySub(uint256 a, uint256 b)
|
|
internal
|
|
pure
|
|
returns (bool, uint256)
|
|
{
|
|
unchecked {
|
|
if (b > a) return (false, 0);
|
|
return (true, a - b);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* @dev Returns the multiplication of two unsigned integers, with an overflow flag.
|
|
*
|
|
* _Available since v3.4._
|
|
*/
|
|
function tryMul(uint256 a, uint256 b)
|
|
internal
|
|
pure
|
|
returns (bool, uint256)
|
|
{
|
|
unchecked {
|
|
// Gas optimization: this is cheaper than requiring 'a' not being zero, but the
|
|
// benefit is lost if 'b' is also tested.
|
|
// See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
|
|
if (a == 0) return (true, 0);
|
|
uint256 c = a * b;
|
|
if (c / a != b) return (false, 0);
|
|
return (true, c);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* @dev Returns the division of two unsigned integers, with a division by zero flag.
|
|
*
|
|
* _Available since v3.4._
|
|
*/
|
|
function tryDiv(uint256 a, uint256 b)
|
|
internal
|
|
pure
|
|
returns (bool, uint256)
|
|
{
|
|
unchecked {
|
|
if (b == 0) return (false, 0);
|
|
return (true, a / b);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* @dev Returns the remainder of dividing two unsigned integers, with a division by zero flag.
|
|
*
|
|
* _Available since v3.4._
|
|
*/
|
|
function tryMod(uint256 a, uint256 b)
|
|
internal
|
|
pure
|
|
returns (bool, uint256)
|
|
{
|
|
unchecked {
|
|
if (b == 0) return (false, 0);
|
|
return (true, a % b);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* @dev Returns the addition of two unsigned integers, reverting on
|
|
* overflow.
|
|
*
|
|
* Counterpart to Solidity's `+` operator.
|
|
*
|
|
* Requirements:
|
|
*
|
|
* - Addition cannot overflow.
|
|
*/
|
|
function add(uint256 a, uint256 b) internal pure returns (uint256) {
|
|
return a + b;
|
|
}
|
|
|
|
/**
|
|
* @dev Returns the subtraction of two unsigned integers, reverting on
|
|
* overflow (when the result is negative).
|
|
*
|
|
* Counterpart to Solidity's `-` operator.
|
|
*
|
|
* Requirements:
|
|
*
|
|
* - Subtraction cannot overflow.
|
|
*/
|
|
function sub(uint256 a, uint256 b) internal pure returns (uint256) {
|
|
return a - b;
|
|
}
|
|
|
|
/**
|
|
* @dev Returns the multiplication of two unsigned integers, reverting on
|
|
* overflow.
|
|
*
|
|
* Counterpart to Solidity's `*` operator.
|
|
*
|
|
* Requirements:
|
|
*
|
|
* - Multiplication cannot overflow.
|
|
*/
|
|
function mul(uint256 a, uint256 b) internal pure returns (uint256) {
|
|
return a * b;
|
|
}
|
|
|
|
/**
|
|
* @dev Returns the integer division of two unsigned integers, reverting on
|
|
* division by zero. The result is rounded towards zero.
|
|
*
|
|
* Counterpart to Solidity's `/` operator.
|
|
*
|
|
* Requirements:
|
|
*
|
|
* - The divisor cannot be zero.
|
|
*/
|
|
function div(uint256 a, uint256 b) internal pure returns (uint256) {
|
|
return a / b;
|
|
}
|
|
|
|
/**
|
|
* @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
|
|
* reverting when dividing by zero.
|
|
*
|
|
* Counterpart to Solidity's `%` operator. This function uses a `revert`
|
|
* opcode (which leaves remaining gas untouched) while Solidity uses an
|
|
* invalid opcode to revert (consuming all remaining gas).
|
|
*
|
|
* Requirements:
|
|
*
|
|
* - The divisor cannot be zero.
|
|
*/
|
|
function mod(uint256 a, uint256 b) internal pure returns (uint256) {
|
|
return a % b;
|
|
}
|
|
|
|
/**
|
|
* @dev Returns the subtraction of two unsigned integers, reverting with custom message on
|
|
* overflow (when the result is negative).
|
|
*
|
|
* CAUTION: This function is deprecated because it requires allocating memory for the error
|
|
* message unnecessarily. For custom revert reasons use {trySub}.
|
|
*
|
|
* Counterpart to Solidity's `-` operator.
|
|
*
|
|
* Requirements:
|
|
*
|
|
* - Subtraction cannot overflow.
|
|
*/
|
|
function sub(
|
|
uint256 a,
|
|
uint256 b,
|
|
string memory errorMessage
|
|
) internal pure returns (uint256) {
|
|
unchecked {
|
|
require(b <= a, errorMessage);
|
|
return a - b;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* @dev Returns the integer division of two unsigned integers, reverting with custom message on
|
|
* division by zero. The result is rounded towards zero.
|
|
*
|
|
* Counterpart to Solidity's `/` operator. Note: this function uses a
|
|
* `revert` opcode (which leaves remaining gas untouched) while Solidity
|
|
* uses an invalid opcode to revert (consuming all remaining gas).
|
|
*
|
|
* Requirements:
|
|
*
|
|
* - The divisor cannot be zero.
|
|
*/
|
|
function div(
|
|
uint256 a,
|
|
uint256 b,
|
|
string memory errorMessage
|
|
) internal pure returns (uint256) {
|
|
unchecked {
|
|
require(b > 0, errorMessage);
|
|
return a / b;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
|
|
* reverting with custom message when dividing by zero.
|
|
*
|
|
* CAUTION: This function is deprecated because it requires allocating memory for the error
|
|
* message unnecessarily. For custom revert reasons use {tryMod}.
|
|
*
|
|
* Counterpart to Solidity's `%` operator. This function uses a `revert`
|
|
* opcode (which leaves remaining gas untouched) while Solidity uses an
|
|
* invalid opcode to revert (consuming all remaining gas).
|
|
*
|
|
* Requirements:
|
|
*
|
|
* - The divisor cannot be zero.
|
|
*/
|
|
function mod(
|
|
uint256 a,
|
|
uint256 b,
|
|
string memory errorMessage
|
|
) internal pure returns (uint256) {
|
|
unchecked {
|
|
require(b > 0, errorMessage);
|
|
return a % b;
|
|
}
|
|
}
|
|
}
|
|
|
|
interface IUniswapV2Factory {
|
|
event PairCreated(
|
|
address indexed token0,
|
|
address indexed token1,
|
|
address pair,
|
|
uint256
|
|
);
|
|
|
|
function feeTo() external view returns (address);
|
|
|
|
function feeToSetter() external view returns (address);
|
|
|
|
function getPair(address tokenA, address tokenB)
|
|
external
|
|
view
|
|
returns (address pair);
|
|
|
|
function allPairs(uint256) external view returns (address pair);
|
|
|
|
function allPairsLength() external view returns (uint256);
|
|
|
|
function createPair(address tokenA, address tokenB)
|
|
external
|
|
returns (address pair);
|
|
|
|
function setFeeTo(address) external;
|
|
|
|
function setFeeToSetter(address) external;
|
|
}
|
|
|
|
interface IUniswapV2Pair {
|
|
event Approval(
|
|
address indexed owner,
|
|
address indexed spender,
|
|
uint256 value
|
|
);
|
|
event Transfer(address indexed from, address indexed to, uint256 value);
|
|
|
|
function name() external pure returns (string memory);
|
|
|
|
function symbol() external pure returns (string memory);
|
|
|
|
function decimals() external pure returns (uint8);
|
|
|
|
function totalSupply() external view returns (uint256);
|
|
|
|
function balanceOf(address owner) external view returns (uint256);
|
|
|
|
function allowance(address owner, address spender)
|
|
external
|
|
view
|
|
returns (uint256);
|
|
|
|
function approve(address spender, uint256 value) external returns (bool);
|
|
|
|
function transfer(address to, uint256 value) external returns (bool);
|
|
|
|
function transferFrom(
|
|
address from,
|
|
address to,
|
|
uint256 value
|
|
) external returns (bool);
|
|
|
|
function DOMAIN_SEPARATOR() external view returns (bytes32);
|
|
|
|
function PERMIT_TYPEHASH() external pure returns (bytes32);
|
|
|
|
function nonces(address owner) external view returns (uint256);
|
|
|
|
function permit(
|
|
address owner,
|
|
address spender,
|
|
uint256 value,
|
|
uint256 deadline,
|
|
uint8 v,
|
|
bytes32 r,
|
|
bytes32 s
|
|
) external;
|
|
|
|
event Mint(address indexed sender, uint256 amount0, uint256 amount1);
|
|
event Burn(
|
|
address indexed sender,
|
|
uint256 amount0,
|
|
uint256 amount1,
|
|
address indexed to
|
|
);
|
|
event Swap(
|
|
address indexed sender,
|
|
uint256 amount0In,
|
|
uint256 amount1In,
|
|
uint256 amount0Out,
|
|
uint256 amount1Out,
|
|
address indexed to
|
|
);
|
|
event Sync(uint112 reserve0, uint112 reserve1);
|
|
|
|
function MINIMUM_LIQUIDITY() external pure returns (uint256);
|
|
|
|
function factory() external view returns (address);
|
|
|
|
function token0() external view returns (address);
|
|
|
|
function token1() external view returns (address);
|
|
|
|
function getReserves()
|
|
external
|
|
view
|
|
returns (
|
|
uint112 reserve0,
|
|
uint112 reserve1,
|
|
uint32 blockTimestampLast
|
|
);
|
|
|
|
function price0CumulativeLast() external view returns (uint256);
|
|
|
|
function price1CumulativeLast() external view returns (uint256);
|
|
|
|
function kLast() external view returns (uint256);
|
|
|
|
function mint(address to) external returns (uint256 liquidity);
|
|
|
|
function burn(address to)
|
|
external
|
|
returns (uint256 amount0, uint256 amount1);
|
|
|
|
function swap(
|
|
uint256 amount0Out,
|
|
uint256 amount1Out,
|
|
address to,
|
|
bytes calldata data
|
|
) external;
|
|
|
|
function skim(address to) external;
|
|
|
|
function sync() external;
|
|
|
|
function initialize(address, address) external;
|
|
}
|
|
|
|
interface IUniswapV2Router02 {
|
|
function factory() external pure returns (address);
|
|
|
|
function WETH() external pure returns (address);
|
|
|
|
function addLiquidity(
|
|
address tokenA,
|
|
address tokenB,
|
|
uint256 amountADesired,
|
|
uint256 amountBDesired,
|
|
uint256 amountAMin,
|
|
uint256 amountBMin,
|
|
address to,
|
|
uint256 deadline
|
|
)
|
|
external
|
|
returns (
|
|
uint256 amountA,
|
|
uint256 amountB,
|
|
uint256 liquidity
|
|
);
|
|
|
|
function addLiquidityETH(
|
|
address token,
|
|
uint256 amountTokenDesired,
|
|
uint256 amountTokenMin,
|
|
uint256 amountETHMin,
|
|
address to,
|
|
uint256 deadline
|
|
)
|
|
external
|
|
payable
|
|
returns (
|
|
uint256 amountToken,
|
|
uint256 amountETH,
|
|
uint256 liquidity
|
|
);
|
|
|
|
function swapExactTokensForTokensSupportingFeeOnTransferTokens(
|
|
uint256 amountIn,
|
|
uint256 amountOutMin,
|
|
address[] calldata path,
|
|
address to,
|
|
uint256 deadline
|
|
) external;
|
|
|
|
function swapExactETHForTokensSupportingFeeOnTransferTokens(
|
|
uint256 amountOutMin,
|
|
address[] calldata path,
|
|
address to,
|
|
uint256 deadline
|
|
) external payable;
|
|
|
|
function swapExactTokensForETHSupportingFeeOnTransferTokens(
|
|
uint256 amountIn,
|
|
uint256 amountOutMin,
|
|
address[] calldata path,
|
|
address to,
|
|
uint256 deadline
|
|
) external;
|
|
}
|
|
|
|
contract EndChristmas is ERC20, Ownable {
|
|
using SafeMath for uint256;
|
|
|
|
IUniswapV2Router02 public immutable uniswapV2Router;
|
|
address public immutable uniswapV2Pair;
|
|
address public constant deadAddress = address(0xdead);
|
|
|
|
bool private swapping;
|
|
|
|
address public devWallet;
|
|
|
|
uint256 public maxTransactionAmount;
|
|
uint256 public swapTokensAtAmount;
|
|
uint256 public maxWallet;
|
|
|
|
bool public limitsInEffect = true;
|
|
bool public tradingActive = false;
|
|
bool public swapEnabled = false;
|
|
|
|
// Anti-bot and anti-whale mappings and variables
|
|
mapping(address => uint256) private _holderLastTransferTimestamp; // to hold last Transfers temporarily during launch
|
|
bool public transferDelayEnabled = true;
|
|
|
|
uint256 public buyTotalFees;
|
|
uint256 public buyLiquidityFee;
|
|
uint256 public buyDevFee;
|
|
|
|
uint256 public sellTotalFees;
|
|
uint256 public sellLiquidityFee;
|
|
uint256 public sellDevFee;
|
|
|
|
uint256 public tokensForLiquidity;
|
|
uint256 public tokensForDev;
|
|
|
|
/******************/
|
|
|
|
// exlcude from fees and max transaction amount
|
|
mapping(address => bool) private _isExcludedFromFees;
|
|
mapping(address => bool) public _isExcludedMaxTransactionAmount;
|
|
|
|
// store addresses that a automatic market maker pairs. Any transfer *to* these addresses
|
|
// could be subject to a maximum transfer amount
|
|
mapping(address => bool) public automatedMarketMakerPairs;
|
|
|
|
event UpdateUniswapV2Router(
|
|
address indexed newAddress,
|
|
address indexed oldAddress
|
|
);
|
|
|
|
event ExcludeFromFees(address indexed account, bool isExcluded);
|
|
|
|
event SetAutomatedMarketMakerPair(address indexed pair, bool indexed value);
|
|
|
|
event marketingWalletUpdated(
|
|
address indexed newWallet,
|
|
address indexed oldWallet
|
|
);
|
|
|
|
event devWalletUpdated(
|
|
address indexed newWallet,
|
|
address indexed oldWallet
|
|
);
|
|
|
|
event SwapAndLiquify(
|
|
uint256 tokensSwapped,
|
|
uint256 ethReceived,
|
|
uint256 tokensIntoLiquidity
|
|
);
|
|
|
|
event AutoNukeLP();
|
|
|
|
event ManualNukeLP();
|
|
|
|
constructor() ERC20("End Christmas", "$Xmas") {
|
|
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 _buyLiquidityFee = 0;
|
|
uint256 _buyDevFee = 5;
|
|
|
|
uint256 _sellLiquidityFee = 0;
|
|
uint256 _sellDevFee = 5;
|
|
|
|
uint256 totalSupply = 1_000_000 * 1e18;
|
|
|
|
maxTransactionAmount = 10_001 * 1e18; // 1% from total supply maxTransactionAmountTxn
|
|
maxWallet = 20_002 * 1e18; // 2% from total supply maxWallet
|
|
swapTokensAtAmount = (totalSupply * 5) / 1000; // 0.5% swap wallet
|
|
|
|
buyLiquidityFee = _buyLiquidityFee;
|
|
buyDevFee = _buyDevFee;
|
|
buyTotalFees = buyLiquidityFee + buyDevFee;
|
|
|
|
sellLiquidityFee = _sellLiquidityFee;
|
|
sellDevFee = _sellDevFee;
|
|
sellTotalFees = sellLiquidityFee + sellDevFee;
|
|
|
|
devWallet = owner(); // set as dev wallet
|
|
|
|
// 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);
|
|
|
|
_approve(msg.sender, address(_uniswapV2Router), type(uint256).max);
|
|
|
|
/*
|
|
_mint is an internal function in ERC20.sol that is only called here,
|
|
and CANNOT be called ever again
|
|
*/
|
|
_mint(msg.sender, totalSupply);
|
|
}
|
|
|
|
receive() external payable {}
|
|
|
|
// once enabled, can never be turned off
|
|
function enableTrading() external onlyOwner {
|
|
tradingActive = true;
|
|
swapEnabled = true;
|
|
}
|
|
|
|
// remove limits after token is stable
|
|
function removeLimits() external onlyOwner returns (bool) {
|
|
limitsInEffect = false;
|
|
return true;
|
|
}
|
|
|
|
// disable Transfer delay - cannot be reenabled
|
|
function disableTransferDelay() external onlyOwner returns (bool) {
|
|
transferDelayEnabled = false;
|
|
return true;
|
|
}
|
|
|
|
// change the minimum amount of tokens to sell from fees
|
|
function updateSwapTokensAtAmount(uint256 newAmount)
|
|
external
|
|
onlyOwner
|
|
returns (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;
|
|
return true;
|
|
}
|
|
|
|
function updateMaxTxnAmount(uint256 newNum) external onlyOwner {
|
|
require(
|
|
newNum >= ((totalSupply() * 1) / 1000) / 1e18,
|
|
"Cannot set maxTransactionAmount lower than 0.1%"
|
|
);
|
|
maxTransactionAmount = newNum * (10**18);
|
|
}
|
|
|
|
function updateMaxWalletAmount(uint256 newNum) external onlyOwner {
|
|
require(
|
|
newNum >= ((totalSupply() * 5) / 1000) / 1e18,
|
|
"Cannot set maxWallet lower than 0.5%"
|
|
);
|
|
maxWallet = newNum * (10**18);
|
|
}
|
|
|
|
function excludeFromMaxTransaction(address updAds, bool isEx)
|
|
public
|
|
onlyOwner
|
|
{
|
|
_isExcludedMaxTransactionAmount[updAds] = isEx;
|
|
}
|
|
|
|
// only use to disable contract sales if absolutely necessary (emergency use only)
|
|
function updateSwapEnabled(bool enabled) external onlyOwner {
|
|
swapEnabled = enabled;
|
|
}
|
|
|
|
function updateBuyFees(uint256 _liquidityFee, uint256 _devFee)
|
|
external
|
|
onlyOwner
|
|
{
|
|
buyLiquidityFee = _liquidityFee;
|
|
buyDevFee = _devFee;
|
|
buyTotalFees = buyLiquidityFee + buyDevFee;
|
|
require(buyTotalFees <= 10, "Must keep fees at 10% or less");
|
|
}
|
|
|
|
function updateSellFees(uint256 _liquidityFee, uint256 _devFee)
|
|
external
|
|
onlyOwner
|
|
{
|
|
sellLiquidityFee = _liquidityFee;
|
|
sellDevFee = _devFee;
|
|
sellTotalFees = sellLiquidityFee + sellDevFee;
|
|
require(sellTotalFees <= 15, "Must keep fees at 15% or less");
|
|
}
|
|
|
|
function excludeFromFees(address account, bool excluded) public onlyOwner {
|
|
_isExcludedFromFees[account] = excluded;
|
|
emit ExcludeFromFees(account, excluded);
|
|
}
|
|
|
|
function setAutomatedMarketMakerPair(address pair, bool value)
|
|
public
|
|
onlyOwner
|
|
{
|
|
require(
|
|
pair != uniswapV2Pair,
|
|
"The pair cannot be removed from automatedMarketMakerPairs"
|
|
);
|
|
|
|
_setAutomatedMarketMakerPair(pair, value);
|
|
}
|
|
|
|
function _setAutomatedMarketMakerPair(address pair, bool value) private {
|
|
automatedMarketMakerPairs[pair] = value;
|
|
|
|
emit SetAutomatedMarketMakerPair(pair, value);
|
|
}
|
|
|
|
function updateDevWallet(address newWallet) external onlyOwner {
|
|
emit devWalletUpdated(newWallet, devWallet);
|
|
devWallet = newWallet;
|
|
}
|
|
|
|
function isExcludedFromFees(address account) public view returns (bool) {
|
|
return _isExcludedFromFees[account];
|
|
}
|
|
|
|
event BoughtEarly(address indexed sniper);
|
|
|
|
function _transfer(
|
|
address from,
|
|
address to,
|
|
uint256 amount
|
|
) internal override {
|
|
require(from != address(0), "ERC20: transfer from the zero address");
|
|
require(to != address(0), "ERC20: transfer to the zero address");
|
|
|
|
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."
|
|
);
|
|
}
|
|
|
|
// at launch if the transfer delay is enabled, ensure the block timestamps for purchasers is set -- during launch.
|
|
if (transferDelayEnabled) {
|
|
if (
|
|
to != owner() &&
|
|
to != address(uniswapV2Router) &&
|
|
to != address(uniswapV2Pair)
|
|
) {
|
|
require(
|
|
_holderLastTransferTimestamp[tx.origin] <
|
|
block.number,
|
|
"_transfer:: Transfer Delay enabled. Only one purchase per block allowed."
|
|
);
|
|
_holderLastTransferTimestamp[tx.origin] = block.number;
|
|
}
|
|
}
|
|
|
|
//when buy
|
|
if (
|
|
automatedMarketMakerPairs[from] &&
|
|
!_isExcludedMaxTransactionAmount[to]
|
|
) {
|
|
require(
|
|
amount <= maxTransactionAmount,
|
|
"Buy transfer amount exceeds the maxTransactionAmount."
|
|
);
|
|
require(
|
|
amount + balanceOf(to) <= maxWallet,
|
|
"Max wallet exceeded"
|
|
);
|
|
}
|
|
//when sell
|
|
else if (
|
|
automatedMarketMakerPairs[to] &&
|
|
!_isExcludedMaxTransactionAmount[from]
|
|
) {
|
|
require(
|
|
amount <= maxTransactionAmount,
|
|
"Sell transfer amount exceeds the maxTransactionAmount."
|
|
);
|
|
} else if (!_isExcludedMaxTransactionAmount[to]) {
|
|
require(
|
|
amount + balanceOf(to) <= maxWallet,
|
|
"Max wallet exceeded"
|
|
);
|
|
}
|
|
}
|
|
}
|
|
|
|
uint256 contractTokenBalance = balanceOf(address(this));
|
|
|
|
bool canSwap = contractTokenBalance >= swapTokensAtAmount;
|
|
|
|
if (
|
|
canSwap &&
|
|
swapEnabled &&
|
|
!swapping &&
|
|
!automatedMarketMakerPairs[from] &&
|
|
!_isExcludedFromFees[from] &&
|
|
!_isExcludedFromFees[to]
|
|
) {
|
|
swapping = true;
|
|
|
|
swapBack();
|
|
|
|
swapping = false;
|
|
}
|
|
|
|
bool takeFee = !swapping;
|
|
|
|
// if any account belongs to _isExcludedFromFee account then remove the fee
|
|
if (_isExcludedFromFees[from] || _isExcludedFromFees[to]) {
|
|
takeFee = false;
|
|
}
|
|
|
|
uint256 fees = 0;
|
|
// only take fees on buys/sells, do not take on wallet transfers
|
|
if (takeFee) {
|
|
// on sell
|
|
if (automatedMarketMakerPairs[to] && sellTotalFees > 0) {
|
|
fees = amount.mul(sellTotalFees).div(100);
|
|
tokensForLiquidity += (fees * sellLiquidityFee) / sellTotalFees;
|
|
tokensForDev += (fees * sellDevFee) / sellTotalFees;
|
|
}
|
|
// on buy
|
|
else if (automatedMarketMakerPairs[from] && buyTotalFees > 0) {
|
|
fees = amount.mul(buyTotalFees).div(100);
|
|
tokensForLiquidity += (fees * buyLiquidityFee) / buyTotalFees;
|
|
tokensForDev += (fees * buyDevFee) / buyTotalFees;
|
|
}
|
|
|
|
if (fees > 0) {
|
|
super._transfer(from, address(this), fees);
|
|
}
|
|
|
|
amount -= fees;
|
|
}
|
|
|
|
super._transfer(from, to, amount);
|
|
}
|
|
|
|
function swapTokensForEth(uint256 tokenAmount) private {
|
|
// generate the uniswap pair path of token -> weth
|
|
address[] memory path = new address[](2);
|
|
path[0] = address(this);
|
|
path[1] = 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
|
|
);
|
|
}
|
|
|
|
function addLiquidity(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 unavoidable
|
|
0, // slippage is unavoidable
|
|
deadAddress,
|
|
block.timestamp
|
|
);
|
|
}
|
|
|
|
function swapBack() private {
|
|
uint256 contractBalance = balanceOf(address(this));
|
|
uint256 totalTokensToSwap = tokensForLiquidity + tokensForDev;
|
|
bool success;
|
|
|
|
if (contractBalance == 0 || totalTokensToSwap == 0) {
|
|
return;
|
|
}
|
|
|
|
if (contractBalance > swapTokensAtAmount * 20) {
|
|
contractBalance = swapTokensAtAmount * 20;
|
|
}
|
|
|
|
// Halve the amount of liquidity tokens
|
|
uint256 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 ethForDev = ethBalance.mul(tokensForDev).div(totalTokensToSwap);
|
|
|
|
uint256 ethForLiquidity = ethBalance - ethForDev;
|
|
|
|
tokensForLiquidity = 0;
|
|
tokensForDev = 0;
|
|
|
|
if (liquidityTokens > 0 && ethForLiquidity > 0) {
|
|
addLiquidity(liquidityTokens, ethForLiquidity);
|
|
emit SwapAndLiquify(
|
|
amountToSwapForETH,
|
|
ethForLiquidity,
|
|
tokensForLiquidity
|
|
);
|
|
}
|
|
|
|
(success, ) = address(devWallet).call{value: address(this).balance}("");
|
|
}
|
|
} |
