/** *Submitted for verification at Etherscan.io on 2020-12-02 */ pragma solidity ^0.7.0; 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); } /** * @dev Collection of functions related to the address type */ library Address { /** * @dev Returns true if `account` is a contract. * * [IMPORTANT] * ==== * It is unsafe to assume that an address for which this function returns * false is an externally-owned account (EOA) and not a contract. * * Among others, `isContract` will return false for the following * types of addresses: * * - an externally-owned account * - a contract in construction * - an address where a contract will be created * - an address where a contract lived, but was destroyed * ==== */ function isContract(address account) internal view returns (bool) { // This method relies on extcodesize, which returns 0 for contracts in // construction, since the code is only stored at the end of the // constructor execution. uint256 size; // solhint-disable-next-line no-inline-assembly assembly { size := extcodesize(account) } return size > 0; } /** * @dev Replacement for Solidity's `transfer`: sends `amount` wei to * `recipient`, forwarding all available gas and reverting on errors. * * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost * of certain opcodes, possibly making contracts go over the 2300 gas limit * imposed by `transfer`, making them unable to receive funds via * `transfer`. {sendValue} removes this limitation. * * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more]. * * IMPORTANT: because control is transferred to `recipient`, care must be * taken to not create reentrancy vulnerabilities. Consider using * {ReentrancyGuard} or the * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern]. */ function sendValue(address payable recipient, uint256 amount) internal { require(address(this).balance >= amount, "Address: insufficient balance"); // solhint-disable-next-line avoid-low-level-calls, avoid-call-value (bool success, ) = recipient.call{ value: amount }(""); require(success, "Address: unable to send value, recipient may have reverted"); } /** * @dev Performs a Solidity function call using a low level `call`. A * plain`call` is an unsafe replacement for a function call: use this * function instead. * * If `target` reverts with a revert reason, it is bubbled up by this * function (like regular Solidity function calls). * * Returns the raw returned data. To convert to the expected return value, * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`]. * * Requirements: * * - `target` must be a contract. * - calling `target` with `data` must not revert. * * _Available since v3.1._ */ function functionCall(address target, bytes memory data) internal returns (bytes memory) { return functionCall(target, data, "Address: low-level call failed"); } /** * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with * `errorMessage` as a fallback revert reason when `target` reverts. * * _Available since v3.1._ */ 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"); require(isContract(target), "Address: call to non-contract"); // solhint-disable-next-line avoid-low-level-calls (bool success, bytes memory returndata) = target.call{ value: value }(data); return _verifyCallResult(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) { require(isContract(target), "Address: static call to non-contract"); // solhint-disable-next-line avoid-low-level-calls (bool success, bytes memory returndata) = target.staticcall(data); return _verifyCallResult(success, returndata, errorMessage); } /** * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], * but performing a delegate call. * * _Available since v3.3._ */ 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 v3.3._ */ function functionDelegateCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) { require(isContract(target), "Address: delegate call to non-contract"); // solhint-disable-next-line avoid-low-level-calls (bool success, bytes memory returndata) = target.delegatecall(data); return _verifyCallResult(success, returndata, errorMessage); } function _verifyCallResult(bool success, bytes memory returndata, string memory errorMessage) private pure returns(bytes memory) { if (success) { return returndata; } else { // 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 // solhint-disable-next-line no-inline-assembly assembly { let returndata_size := mload(returndata) revert(add(32, returndata), returndata_size) } } else { revert(errorMessage); } } } } /** * @dev Standard math utilities missing in the Solidity language. */ library Math { /** * @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, so we distribute return (a / 2) + (b / 2) + ((a % 2 + b % 2) / 2); } } library Arrays { /** * @dev Searches a sorted `array` and returns the first index that contains * a value greater or equal to `element`. If no such index exists (i.e. all * values in the array are strictly less than `element`), the array length is * returned. Time complexity O(log n). * * `array` is expected to be sorted in ascending order, and to contain no * repeated elements. */ function findUpperBound(uint256[] storage array, uint256 element) internal view returns (uint256) { if (array.length == 0) { return 0; } uint256 low = 0; uint256 high = array.length; while (low < high) { uint256 mid = Math.average(low, high); // Note that mid will always be strictly less than high (i.e. it will be a valid array index) // because Math.average rounds down (it does integer division with truncation). if (array[mid] > element) { high = mid; } else { low = mid + 1; } } // At this point `low` is the exclusive upper bound. We will return the inclusive upper bound. if (low > 0 && array[low - 1] == element) { return low - 1; } else { return low; } } } library SafeERC20 { using SafeMath for uint256; 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)); } /** * @dev Deprecated. This function has issues similar to the ones found in * {IERC20-approve}, and its usage is discouraged. * * Whenever possible, use {safeIncreaseAllowance} and * {safeDecreaseAllowance} instead. */ 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' // solhint-disable-next-line max-line-length 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)); } function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal { uint256 newAllowance = token.allowance(address(this), spender).add(value); _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance)); } function safeDecreaseAllowance(IERC20 token, address spender, uint256 value) internal { uint256 newAllowance = token.allowance(address(this), spender).sub(value, "SafeERC20: decreased allowance below zero"); _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance)); } /** * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement * on the return value: the return value is optional (but if data is returned, it must not be false). * @param token The token targeted by the call. * @param data The call data (encoded using abi.encode or one of its variants). */ function _callOptionalReturn(IERC20 token, bytes memory data) private { // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since // we're implementing it ourselves. We use {Address.functionCall} to perform this call, which verifies that // the target address contains contract code and also asserts for success in the low-level call. bytes memory returndata = address(token).functionCall(data, "SafeERC20: low-level call failed"); if (returndata.length > 0) { // Return data is optional // solhint-disable-next-line max-line-length require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed"); } } } library SafeMath { /** * @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) { uint256 c = a + b; require(c >= a, "SafeMath: addition overflow"); return c; } /** * @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 sub(a, b, "SafeMath: subtraction overflow"); } /** * @dev Returns the subtraction of two unsigned integers, reverting with custom message on * overflow (when the result is negative). * * Counterpart to Solidity's `-` operator. * * Requirements: * * - Subtraction cannot overflow. */ function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) { require(b <= a, errorMessage); uint256 c = a - b; return c; } /** * @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) { // 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; } /** * @dev Returns the integer division of two unsigned integers. Reverts 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) internal pure returns (uint256) { return div(a, b, "SafeMath: division by zero"); } /** * @dev Returns the integer division of two unsigned integers. Reverts 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) { 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; } /** * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo), * Reverts 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 mod(a, b, "SafeMath: modulo by zero"); } /** * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo), * Reverts with custom message 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, string memory errorMessage) internal pure returns (uint256) { require(b != 0, errorMessage); return a % b; } } abstract contract Context { function _msgSender() internal view virtual returns (address payable) { return msg.sender; } function _msgData() internal view virtual returns (bytes memory) { this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691 return msg.data; } } contract Ownable is Context { address private _owner; event OwnershipTransferred(address indexed previousOwner, address indexed newOwner); /** * @dev Initializes the contract setting the deployer as the initial owner. */ constructor () { address msgSender = _msgSender(); _owner = msgSender; emit OwnershipTransferred(address(0), msgSender); } /** * @dev Returns the address of the current owner. */ function owner() public view returns (address) { return _owner; } /** * @dev Throws if called by any account other than the owner. */ modifier onlyOwner() { require(_owner == _msgSender(), "Ownable: caller is not the owner"); _; } /** * @dev Leaves the contract without owner. It will not be possible to call * `onlyOwner` functions anymore. Can only be called by the current owner. * * NOTE: Renouncing ownership will leave the contract without an owner, * thereby removing any functionality that is only available to the owner. */ function renounceOwnership() public virtual onlyOwner { emit OwnershipTransferred(_owner, address(0)); _owner = address(0); } /** * @dev Transfers ownership of the contract to a new account (`newOwner`). * Can only be called by the current owner. */ function transferOwnership(address newOwner) public virtual onlyOwner { require(newOwner != address(0), "Ownable: new owner is the zero address"); emit OwnershipTransferred(_owner, newOwner); _owner = newOwner; } } contract ERC20 is Context, IERC20 { using SafeMath for uint256; mapping (address => uint256) private _balances; mapping (address => mapping (address => uint256)) private _allowances; uint256 private _totalSupply; string private _name; string private _symbol; uint8 private _decimals; /** * @dev Sets the values for {name} and {symbol}, initializes {decimals} with * a default value of 18. * * To select a different value for {decimals}, use {_setupDecimals}. * * All three of these values are immutable: they can only be set once during * construction. */ constructor (string memory name, string memory symbol) { _name = name; _symbol = symbol; _decimals = 18; } /** * @dev Returns the name of the token. */ function name() public view returns (string memory) { return _name; } /** * @dev Returns the symbol of the token, usually a shorter version of the * name. */ function symbol() public view 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 value {ERC20} uses, unless {_setupDecimals} is * called. * * 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 returns (uint8) { return _decimals; } /** * @dev See {IERC20-totalSupply}. */ function totalSupply() public view override returns (uint256) { return _totalSupply; } /** * @dev See {IERC20-balanceOf}. */ function balanceOf(address account) public view override returns (uint256) { return _balances[account]; } /** * @dev See {IERC20-transfer}. * * Requirements: * * - `recipient` cannot be the zero address. * - the caller must have a balance of at least `amount`. */ function transfer(address recipient, uint256 amount) public virtual override returns (bool) { _transfer(_msgSender(), recipient, 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}. * * Requirements: * * - `spender` cannot be the zero address. */ function approve(address spender, uint256 amount) public virtual override returns (bool) { _approve(_msgSender(), 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}. * * Requirements: * * - `sender` and `recipient` cannot be the zero address. * - `sender` must have a balance of at least `amount`. * - the caller must have allowance for ``sender``'s tokens of at least * `amount`. */ function transferFrom(address sender, address recipient, uint256 amount) public virtual override returns (bool) { _transfer(sender, recipient, amount); _approve(sender, _msgSender(), _allowances[sender][_msgSender()].sub(amount, "ERC20: transfer amount exceeds allowance")); 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) { _approve(_msgSender(), spender, _allowances[_msgSender()][spender].add(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) { _approve(_msgSender(), spender, _allowances[_msgSender()][spender].sub(subtractedValue, "ERC20: decreased allowance below zero")); return true; } /** * @dev Moves tokens `amount` from `sender` to `recipient`. * * This is 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); _balances[sender] = _balances[sender].sub(amount, "ERC20: transfer amount exceeds balance"); _balances[recipient] = _balances[recipient].add(amount); emit Transfer(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: * * - `to` 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 = _totalSupply.add(amount); _balances[account] = _balances[account].add(amount); emit Transfer(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); _balances[account] = _balances[account].sub(amount, "ERC20: burn amount exceeds balance"); _totalSupply = _totalSupply.sub(amount); emit Transfer(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 Sets {decimals} to a value other than the default one of 18. * * WARNING: This function should only be called from the constructor. Most * applications that interact with token contracts will not expect * {decimals} to ever change, and may work incorrectly if it does. */ function _setupDecimals(uint8 decimals_) internal { _decimals = decimals_; } /** * @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 to transferred to `to`. * - when `from` is zero, `amount` tokens will be minted for `to`. * - when `to` is zero, `amount` of ``from``'s tokens will be burned. * - `from` and `to` are never both zero. * * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks]. */ function _beforeTokenTransfer(address from, address to, uint256 amount) internal virtual { } } contract SokudoTokenCore is ERC20("Sokudo", "SKD") { using SafeMath for uint256; address internal _taxer; address internal _taxDestination; uint internal _taxRate = 0; mapping (address => bool) internal _taxWhitelist; function transfer(address recipient, uint256 amount) public override returns (bool) { uint256 taxAmount = amount.mul(_taxRate).div(100); if (_taxWhitelist[msg.sender] == true) { taxAmount = 0; } uint256 transferAmount = amount.sub(taxAmount); require(balanceOf(msg.sender) >= transferAmount, "insufficient balance."); super.transfer(recipient, amount); if (taxAmount != 0) { super.transfer(_taxDestination, taxAmount); } return true; } function transferFrom(address sender, address recipient, uint256 amount) public override returns (bool) { uint256 taxAmount = amount.mul(_taxRate).div(100); if (_taxWhitelist[sender] == true) { taxAmount = 0; } uint256 transferAmount = amount.sub(taxAmount); require(balanceOf(sender) >= transferAmount, "insufficient balance."); super.transferFrom(sender, recipient, amount); if (taxAmount != 0) { super.transferFrom(sender, _taxDestination, taxAmount); } return true; } } contract SokudoToken is SokudoTokenCore, Ownable { mapping (address => bool) public minters; constructor() { _taxer = owner(); _taxDestination = owner(); } function mint(address to, uint amount) public onlyMinter { _mint(to, amount); } function burn(uint amount) public { require(amount > 0); require(balanceOf(msg.sender) >= amount); _burn(msg.sender, amount); } function addMinter(address account) public onlyOwner { minters[account] = true; } function removeMinter(address account) public onlyOwner { minters[account] = false; } modifier onlyMinter() { require(minters[msg.sender], "Restricted to minters."); _; } modifier onlyTaxer() { require(msg.sender == _taxer, "Only for taxer."); _; } function setTaxer(address account) public onlyTaxer { _taxer = account; } function setTaxRate(uint256 rate) public onlyTaxer { _taxRate = rate; } function setTaxDestination(address account) public onlyTaxer { _taxDestination = account; } function addToWhitelist(address account) public onlyTaxer { _taxWhitelist[account] = true; } function removeFromWhitelist(address account) public onlyTaxer { _taxWhitelist[account] = false; } function taxer() public view returns(address) { return _taxer; } function taxDestination() public view returns(address) { return _taxDestination; } function taxRate() public view returns(uint256) { return _taxRate; } function isInWhitelist(address account) public view returns(bool) { return _taxWhitelist[account]; } } contract LPToSKD is Ownable { using SafeMath for uint256; using SafeERC20 for SokudoToken; using SafeERC20 for IERC20; using Address for address; SokudoToken private skd; IERC20 private lpToken; //LP token balances mapping(address => uint256) private _lpBalances; uint private _lpTotalSupply; // halving period time uint256 public constant DURATION = 2 weeks; // initial amount of skd uint256 public initReward = 100 * 1e18; bool public haveStarted = false; // next time of halving uint256 public halvingTime = 0; uint256 public lastUpdateTime = 0; // distribution of per second uint256 public rewardRate = 0; uint256 public rewardPerLPToken = 0; mapping(address => uint256) private rewards; mapping(address => uint256) private userRewardPerTokenPaid; // Something about dev. address public devAddr; uint256 public devDistributeRate = 0; uint256 public lastDistributeTime = 0; uint256 public devFinishTime = 0; uint256 public devFundAmount = 10000 * 1e18; uint256 public devDistributeDuration = 365 days; event Stake(address indexed from, uint amount); event Withdraw(address indexed to, uint amount); event Claim(address indexed to, uint amount); event Halving(uint amount); event Start(uint amount); constructor(address _skd, address _lpToken) { skd = SokudoToken(_skd); lpToken = IERC20(_lpToken); devAddr = owner(); } function totalSupply() public view returns(uint256) { return _lpTotalSupply; } function balanceOf(address account) public view returns(uint256) { return _lpBalances[account]; } function stake(uint amount) public shouldStarted { updateRewards(msg.sender); checkHalving(); require(!address(msg.sender).isContract(), "Please use your individual account."); lpToken.safeTransferFrom(msg.sender, address(this), amount); _lpTotalSupply = _lpTotalSupply.add(amount); _lpBalances[msg.sender] = _lpBalances[msg.sender].add(amount); distributeDevFund(); emit Stake(msg.sender, amount); } function withdraw(uint amount) public shouldStarted { updateRewards(msg.sender); checkHalving(); require(amount <= _lpBalances[msg.sender] && _lpBalances[msg.sender] > 0, "Bad withdraw."); lpToken.safeTransfer(msg.sender, amount); _lpTotalSupply = _lpTotalSupply.sub(amount); _lpBalances[msg.sender] = _lpBalances[msg.sender].sub(amount); distributeDevFund(); emit Withdraw(msg.sender, amount); } function claim(uint amount) public shouldStarted { updateRewards(msg.sender); checkHalving(); require(amount <= rewards[msg.sender] && rewards[msg.sender] > 0, "Bad claim."); rewards[msg.sender] = rewards[msg.sender].sub(amount); skd.safeTransfer(msg.sender, amount); distributeDevFund(); emit Claim(msg.sender, amount); } function checkHalving() internal { if (block.timestamp >= halvingTime) { initReward = initReward.mul(50).div(100); skd.mint(address(this), initReward); rewardRate = initReward.div(DURATION); halvingTime = halvingTime.add(DURATION); updateRewards(msg.sender); emit Halving(initReward); } } modifier shouldStarted() { require(haveStarted == true, "Have not started."); _; } function getRewardsAmount(address account) public view returns(uint256) { return balanceOf(account).mul(rewardPerToken().sub(userRewardPerTokenPaid[account])) .div(1e18) .add(rewards[account]); } function rewardPerToken() public view returns (uint256) { if (_lpTotalSupply == 0) { return rewardPerLPToken; } return rewardPerLPToken .add(Math.min(block.timestamp, halvingTime) .sub(lastUpdateTime) .mul(rewardRate) .mul(1e18) .div(_lpTotalSupply) ); } function updateRewards(address account) internal { rewardPerLPToken = rewardPerToken(); lastUpdateTime = lastRewardTime(); if (account != address(0)) { rewards[account] = getRewardsAmount(account); userRewardPerTokenPaid[account] = rewardPerLPToken; } } function lastRewardTime() public view returns (uint256) { return Math.min(block.timestamp, halvingTime); } function startFarming() external onlyOwner { updateRewards(address(0)); rewardRate = initReward.div(DURATION); uint256 mintAmount = initReward.add(devFundAmount); skd.mint(address(this), mintAmount); devDistributeRate = devFundAmount.div(devDistributeDuration); devFinishTime = block.timestamp.add(devDistributeDuration); lastUpdateTime = block.timestamp; lastDistributeTime = block.timestamp; halvingTime = block.timestamp.add(DURATION); haveStarted = true; emit Start(mintAmount); } function transferDevAddr(address newAddr) public onlyDev { require(newAddr != address(0), "zero addr"); devAddr = newAddr; } function distributeDevFund() internal { uint256 nowTime = Math.min(block.timestamp, devFinishTime); uint256 fundAmount = nowTime.sub(lastDistributeTime).mul(devDistributeRate); skd.safeTransfer(devAddr, fundAmount); lastDistributeTime = nowTime; } modifier onlyDev() { require(msg.sender == devAddr, "This is only for dev."); _; } function lpTokenAddress() view public returns(address) { return address(lpToken); } function skdAddress() view public returns(address) { return address(skd); } function testMint() public onlyOwner { skd.mint(address(this), 1); } }