{{
"language": "Solidity",
"sources": {
"@openzeppelin/contracts/token/ERC20/ERC20.sol": {
"content": "// SPDX-License-Identifier: MIT\n\npragma solidity ^0.8.0;\n\nimport \"./IERC20.sol\";\nimport \"./extensions/IERC20Metadata.sol\";\nimport \"../../utils/Context.sol\";\n\n/**\n * @dev Implementation of the {IERC20} interface.\n *\n * This implementation is agnostic to the way tokens are created. This means\n * that a supply mechanism has to be added in a derived contract using {_mint}.\n * For a generic mechanism see {ERC20PresetMinterPauser}.\n *\n * TIP: For a detailed writeup see our guide\n * https://forum.zeppelin.solutions/t/how-to-implement-erc20-supply-mechanisms/226[How\n * to implement supply mechanisms].\n *\n * We have followed general OpenZeppelin Contracts guidelines: functions revert\n * instead returning `false` on failure. This behavior is nonetheless\n * conventional and does not conflict with the expectations of ERC20\n * applications.\n *\n * Additionally, an {Approval} event is emitted on calls to {transferFrom}.\n * This allows applications to reconstruct the allowance for all accounts just\n * by listening to said events. Other implementations of the EIP may not emit\n * these events, as it isn't required by the specification.\n *\n * Finally, the non-standard {decreaseAllowance} and {increaseAllowance}\n * functions have been added to mitigate the well-known issues around setting\n * allowances. See {IERC20-approve}.\n */\ncontract ERC20 is Context, IERC20, IERC20Metadata {\n mapping(address => uint256) private _balances;\n\n mapping(address => mapping(address => uint256)) private _allowances;\n\n uint256 private _totalSupply;\n\n string private _name;\n string private _symbol;\n\n /**\n * @dev Sets the values for {name} and {symbol}.\n *\n * The default value of {decimals} is 18. To select a different value for\n * {decimals} you should overload it.\n *\n * All two of these values are immutable: they can only be set once during\n * construction.\n */\n constructor(string memory name_, string memory symbol_) {\n _name = name_;\n _symbol = symbol_;\n }\n\n /**\n * @dev Returns the name of the token.\n */\n function name() public view virtual override returns (string memory) {\n return _name;\n }\n\n /**\n * @dev Returns the symbol of the token, usually a shorter version of the\n * name.\n */\n function symbol() public view virtual override returns (string memory) {\n return _symbol;\n }\n\n /**\n * @dev Returns the number of decimals used to get its user representation.\n * For example, if `decimals` equals `2`, a balance of `505` tokens should\n * be displayed to a user as `5.05` (`505 / 10 ** 2`).\n *\n * Tokens usually opt for a value of 18, imitating the relationship between\n * Ether and Wei. This is the value {ERC20} uses, unless this function is\n * overridden;\n *\n * NOTE: This information is only used for _display_ purposes: it in\n * no way affects any of the arithmetic of the contract, including\n * {IERC20-balanceOf} and {IERC20-transfer}.\n */\n function decimals() public view virtual override returns (uint8) {\n return 18;\n }\n\n /**\n * @dev See {IERC20-totalSupply}.\n */\n function totalSupply() public view virtual override returns (uint256) {\n return _totalSupply;\n }\n\n /**\n * @dev See {IERC20-balanceOf}.\n */\n function balanceOf(address account) public view virtual override returns (uint256) {\n return _balances[account];\n }\n\n /**\n * @dev See {IERC20-transfer}.\n *\n * Requirements:\n *\n * - `recipient` cannot be the zero address.\n * - the caller must have a balance of at least `amount`.\n */\n function transfer(address recipient, uint256 amount) public virtual override returns (bool) {\n _transfer(_msgSender(), recipient, amount);\n return true;\n }\n\n /**\n * @dev See {IERC20-allowance}.\n */\n function allowance(address owner, address spender) public view virtual override returns (uint256) {\n return _allowances[owner][spender];\n }\n\n /**\n * @dev See {IERC20-approve}.\n *\n * Requirements:\n *\n * - `spender` cannot be the zero address.\n */\n function approve(address spender, uint256 amount) public virtual override returns (bool) {\n _approve(_msgSender(), spender, amount);\n return true;\n }\n\n /**\n * @dev See {IERC20-transferFrom}.\n *\n * Emits an {Approval} event indicating the updated allowance. This is not\n * required by the EIP. See the note at the beginning of {ERC20}.\n *\n * Requirements:\n *\n * - `sender` and `recipient` cannot be the zero address.\n * - `sender` must have a balance of at least `amount`.\n * - the caller must have allowance for ``sender``'s tokens of at least\n * `amount`.\n */\n function transferFrom(\n address sender,\n address recipient,\n uint256 amount\n ) public virtual override returns (bool) {\n _transfer(sender, recipient, amount);\n\n uint256 currentAllowance = _allowances[sender][_msgSender()];\n require(currentAllowance >= amount, \"ERC20: transfer amount exceeds allowance\");\n unchecked {\n _approve(sender, _msgSender(), currentAllowance - amount);\n }\n\n return true;\n }\n\n /**\n * @dev Atomically increases the allowance granted to `spender` by the caller.\n *\n * This is an alternative to {approve} that can be used as a mitigation for\n * problems described in {IERC20-approve}.\n *\n * Emits an {Approval} event indicating the updated allowance.\n *\n * Requirements:\n *\n * - `spender` cannot be the zero address.\n */\n function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {\n _approve(_msgSender(), spender, _allowances[_msgSender()][spender] addedValue);\n return true;\n }\n\n /**\n * @dev Atomically decreases the allowance granted to `spender` by the caller.\n *\n * This is an alternative to {approve} that can be used as a mitigation for\n * problems described in {IERC20-approve}.\n *\n * Emits an {Approval} event indicating the updated allowance.\n *\n * Requirements:\n *\n * - `spender` cannot be the zero address.\n * - `spender` must have allowance for the caller of at least\n * `subtractedValue`.\n */\n function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {\n uint256 currentAllowance = _allowances[_msgSender()][spender];\n require(currentAllowance >= subtractedValue, \"ERC20: decreased allowance below zero\");\n unchecked {\n _approve(_msgSender(), spender, currentAllowance - subtractedValue);\n }\n\n return true;\n }\n\n /**\n * @dev Moves `amount` of tokens from `sender` to `recipient`.\n *\n * This internal function is equivalent to {transfer}, and can be used to\n * e.g. implement automatic token fees, slashing mechanisms, etc.\n *\n * Emits a {Transfer} event.\n *\n * Requirements:\n *\n * - `sender` cannot be the zero address.\n * - `recipient` cannot be the zero address.\n * - `sender` must have a balance of at least `amount`.\n */\n function _transfer(\n address sender,\n address recipient,\n uint256 amount\n ) internal virtual {\n require(sender != address(0), \"ERC20: transfer from the zero address\");\n require(recipient != address(0), \"ERC20: transfer to the zero address\");\n\n _beforeTokenTransfer(sender, recipient, amount);\n\n uint256 senderBalance = _balances[sender];\n require(senderBalance >= amount, \"ERC20: transfer amount exceeds balance\");\n unchecked {\n _balances[sender] = senderBalance - amount;\n }\n _balances[recipient] = amount;\n\n emit Transfer(sender, recipient, amount);\n\n _afterTokenTransfer(sender, recipient, amount);\n }\n\n /** @dev Creates `amount` tokens and assigns them to `account`, increasing\n * the total supply.\n *\n * Emits a {Transfer} event with `from` set to the zero address.\n *\n * Requirements:\n *\n * - `account` cannot be the zero address.\n */\n function _mint(address account, uint256 amount) internal virtual {\n require(account != address(0), \"ERC20: mint to the zero address\");\n\n _beforeTokenTransfer(address(0), account, amount);\n\n _totalSupply = amount;\n _balances[account] = amount;\n emit Transfer(address(0), account, amount);\n\n _afterTokenTransfer(address(0), account, amount);\n }\n\n /**\n * @dev Destroys `amount` tokens from `account`, reducing the\n * total supply.\n *\n * Emits a {Transfer} event with `to` set to the zero address.\n *\n * Requirements:\n *\n * - `account` cannot be the zero address.\n * - `account` must have at least `amount` tokens.\n */\n function _burn(address account, uint256 amount) internal virtual {\n require(account != address(0), \"ERC20: burn from the zero address\");\n\n _beforeTokenTransfer(account, address(0), amount);\n\n uint256 accountBalance = _balances[account];\n require(accountBalance >= amount, \"ERC20: burn amount exceeds balance\");\n unchecked {\n _balances[account] = accountBalance - amount;\n }\n _totalSupply -= amount;\n\n emit Transfer(account, address(0), amount);\n\n _afterTokenTransfer(account, address(0), amount);\n }\n\n /**\n * @dev Sets `amount` as the allowance of `spender` over the `owner` s tokens.\n *\n * This internal function is equivalent to `approve`, and can be used to\n * e.g. set automatic allowances for certain subsystems, etc.\n *\n * Emits an {Approval} event.\n *\n * Requirements:\n *\n * - `owner` cannot be the zero address.\n * - `spender` cannot be the zero address.\n */\n function _approve(\n address owner,\n address spender,\n uint256 amount\n ) internal virtual {\n require(owner != address(0), \"ERC20: approve from the zero address\");\n require(spender != address(0), \"ERC20: approve to the zero address\");\n\n _allowances[owner][spender] = amount;\n emit Approval(owner, spender, amount);\n }\n\n /**\n * @dev Hook that is called before any transfer of tokens. This includes\n * minting and burning.\n *\n * Calling conditions:\n *\n * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens\n * will be transferred to `to`.\n * - when `from` is zero, `amount` tokens will be minted for `to`.\n * - when `to` is zero, `amount` of ``from``'s tokens will be burned.\n * - `from` and `to` are never both zero.\n *\n * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].\n */\n function _beforeTokenTransfer(\n address from,\n address to,\n uint256 amount\n ) internal virtual {}\n\n /**\n * @dev Hook that is called after any transfer of tokens. This includes\n * minting and burning.\n *\n * Calling conditions:\n *\n * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens\n * has been transferred to `to`.\n * - when `from` is zero, `amount` tokens have been minted for `to`.\n * - when `to` is zero, `amount` of ``from``'s tokens have been burned.\n * - `from` and `to` are never both zero.\n *\n * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].\n */\n function _afterTokenTransfer(\n address from,\n address to,\n uint256 amount\n ) internal virtual {}\n}\n"
},
"@openzeppelin/contracts/token/ERC20/IERC20.sol": {
"content": "// SPDX-License-Identifier: MIT\n\npragma solidity ^0.8.0;\n\n/**\n * @dev Interface of the ERC20 standard as defined in the EIP.\n */\ninterface IERC20 {\n /**\n * @dev Returns the amount of tokens in existence.\n */\n function totalSupply() external view returns (uint256);\n\n /**\n * @dev Returns the amount of tokens owned by `account`.\n */\n function balanceOf(address account) external view returns (uint256);\n\n /**\n * @dev Moves `amount` tokens from the caller's account to `recipient`.\n *\n * Returns a boolean value indicating whether the operation succeeded.\n *\n * Emits a {Transfer} event.\n */\n function transfer(address recipient, uint256 amount) external returns (bool);\n\n /**\n * @dev Returns the remaining number of tokens that `spender` will be\n * allowed to spend on behalf of `owner` through {transferFrom}. This is\n * zero by default.\n *\n * This value changes when {approve} or {transferFrom} are called.\n */\n function allowance(address owner, address spender) external view returns (uint256);\n\n /**\n * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.\n *\n * Returns a boolean value indicating whether the operation succeeded.\n *\n * IMPORTANT: Beware that changing an allowance with this method brings the risk\n * that someone may use both the old and the new allowance by unfortunate\n * transaction ordering. One possible solution to mitigate this race\n * condition is to first reduce the spender's allowance to 0 and set the\n * desired value afterwards:\n * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729\n *\n * Emits an {Approval} event.\n */\n function approve(address spender, uint256 amount) external returns (bool);\n\n /**\n * @dev Moves `amount` tokens from `sender` to `recipient` using the\n * allowance mechanism. `amount` is then deducted from the caller's\n * allowance.\n *\n * Returns a boolean value indicating whether the operation succeeded.\n *\n * Emits a {Transfer} event.\n */\n function transferFrom(\n address sender,\n address recipient,\n uint256 amount\n ) external returns (bool);\n\n /**\n * @dev Emitted when `value` tokens are moved from one account (`from`) to\n * another (`to`).\n *\n * Note that `value` may be zero.\n */\n event Transfer(address indexed from, address indexed to, uint256 value);\n\n /**\n * @dev Emitted when the allowance of a `spender` for an `owner` is set by\n * a call to {approve}. `value` is the new allowance.\n */\n event Approval(address indexed owner, address indexed spender, uint256 value);\n}\n"
},
"@openzeppelin/contracts/token/ERC20/extensions/ERC20Burnable.sol": {
"content": "// SPDX-License-Identifier: MIT\n\npragma solidity ^0.8.0;\n\nimport \"../ERC20.sol\";\nimport \"../../../utils/Context.sol\";\n\n/**\n * @dev Extension of {ERC20} that allows token holders to destroy both their own\n * tokens and those that they have an allowance for, in a way that can be\n * recognized off-chain (via event analysis).\n */\nabstract contract ERC20Burnable is Context, ERC20 {\n /**\n * @dev Destroys `amount` tokens from the caller.\n *\n * See {ERC20-_burn}.\n */\n function burn(uint256 amount) public virtual {\n _burn(_msgSender(), amount);\n }\n\n /**\n * @dev Destroys `amount` tokens from `account`, deducting from the caller's\n * allowance.\n *\n * See {ERC20-_burn} and {ERC20-allowance}.\n *\n * Requirements:\n *\n * - the caller must have allowance for ``accounts``'s tokens of at least\n * `amount`.\n */\n function burnFrom(address account, uint256 amount) public virtual {\n uint256 currentAllowance = allowance(account, _msgSender());\n require(currentAllowance >= amount, \"ERC20: burn amount exceeds allowance\");\n unchecked {\n _approve(account, _msgSender(), currentAllowance - amount);\n }\n _burn(account, amount);\n }\n}\n"
},
"@openzeppelin/contracts/token/ERC20/extensions/IERC20Metadata.sol": {
"content": "// SPDX-License-Identifier: MIT\n\npragma solidity ^0.8.0;\n\nimport \"../IERC20.sol\";\n\n/**\n * @dev Interface for the optional metadata functions from the ERC20 standard.\n *\n * _Available since v4.1._\n */\ninterface IERC20Metadata is IERC20 {\n /**\n * @dev Returns the name of the token.\n */\n function name() external view returns (string memory);\n\n /**\n * @dev Returns the symbol of the token.\n */\n function symbol() external view returns (string memory);\n\n /**\n * @dev Returns the decimals places of the token.\n */\n function decimals() external view returns (uint8);\n}\n"
},
"@openzeppelin/contracts/utils/Context.sol": {
"content": "// SPDX-License-Identifier: MIT\n\npragma solidity ^0.8.0;\n\n/**\n * @dev Provides information about the current execution context, including the\n * sender of the transaction and its data. While these are generally available\n * via msg.sender and msg.data, they should not be accessed in such a direct\n * manner, since when dealing with meta-transactions the account sending and\n * paying for execution may not be the actual sender (as far as an application\n * is concerned).\n *\n * This contract is only required for intermediate, library-like contracts.\n */\nabstract contract Context {\n function _msgSender() internal view virtual returns (address) {\n return msg.sender;\n }\n\n function _msgData() internal view virtual returns (bytes calldata) {\n return msg.data;\n }\n}\n"
},
"/contracts/Highlander.sol": {
"content": "// SPDX-License-Identifier: MIT\npragma solidity ^0.8.0;\n\nimport \"@openzeppelin/contracts/token/ERC20/ERC20.sol\";\nimport \"@openzeppelin/contracts/token/ERC20/extensions/ERC20Burnable.sol\";\n\ncontract Highlander is ERC20, ERC20Burnable {\n\n address private _highlander;\n uint256 private _one = 1 * 10 ** decimals();\n\n event NewHighlander(address indexed highlander);\n\n constructor() ERC20(\"Highlander\", \"DUEL\") {\n _highlander = msg.sender;\n _mint(msg.sender, 7883000000 * 10 ** decimals());\n }\n\n function getHighlander() public view returns (address) {\n return _highlander;\n }\n\n function setHighlander(address to, uint256 amount) private {\n if(to != address(0) && to != msg.sender && amount > _one) {\n _highlander = to;\n emit NewHighlander(to);\n }\n }\n\n function performTransferBurn(uint256 amount) internal returns (uint256) {\n uint256 burnAmount = calculateBurnAmount(amount);\n if(burnAmount > 0) {\n burn(burnAmount);\n }\n return amount - burnAmount;\n }\n\n function performTransferFromBurn(address from, uint256 amount) internal returns (uint256) {\n uint256 burnAmount = calculateBurnAmount(amount);\n if(burnAmount > 0) {\n burnFrom(from, burnAmount);\n }\n return amount - burnAmount;\n }\n\n function calculateBurnAmount(uint256 amount) internal view returns (uint256) {\n uint256 amountToBurn = 0;\n if(totalSupply() > _one) {\n amountToBurn = amount / 40;\n }\n return amountToBurn;\n }\n\n function transferFrom(address from, address to, uint256 amount) public override returns (bool) {\n return super.transferFrom(from, to, performTransferFromBurn(from, amount));\n }\n \n function transfer(address to, uint256 amount) public override returns (bool) {\n return super.transfer(to, performTransferBurn(amount));\n }\n\n function _afterTokenTransfer(address from, address to, uint256 amount) internal virtual override {\n super._afterTokenTransfer(from, to, amount);\n setHighlander(to, amount);\n }\n}"
}
},
"settings": {
"remappings": [],
"optimizer": {
"enabled": false,
"runs": 200
},
"evmVersion": "london",
"libraries": {},
"outputSelection": {
"*": {
"*": [
"evm.bytecode",
"evm.deployedBytecode",
"abi"
]
}
}
}
}}