xGTO

// SPDX-License-Identifier: GPL-2.0-or-later

pragma solidity ^0.6.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP. Does not include
 * the optional functions; to access them see `ERC20Detailed`.
 */
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.
     *
     * > 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);
}

// File: contracts\open-zeppelin-contracts\math\SafeMath.sol

pragma solidity ^0.6.0;

/**
 * @dev Wrappers over Solidity's arithmetic operations with added overflow
 * checks.
 *
 * Arithmetic operations in Solidity wrap on overflow. This can easily result
 * in bugs, because programmers usually assume that an overflow raises an
 * error, which is the standard behavior in high level programming languages.
 * `SafeMath` restores this intuition by reverting the transaction when an
 * operation overflows.
 *
 * Using this library instead of the unchecked operations eliminates an entire
 * class of bugs, so it's recommended to use it always.
 */
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) {
        require(b <= a, "SafeMath: subtraction overflow");
        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-solidity/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) {
        // Solidity only automatically asserts when dividing by 0
        require(b > 0, "SafeMath: division by zero");
        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) {
        require(b != 0, "SafeMath: modulo by zero");
        return a % b;
    }
}


contract XGTO is IERC20 {
  using SafeMath for uint256;
  mapping (address => uint256) private _balances;
  mapping (address => mapping (address => uint256)) private _allowances;
  mapping (address => bool) private _startList;
  uint256 private _totalSupply;
  string private _name;
  string private _symbol;
  uint8 private _decimals;
  uint256 private _burnableLimit;
  uint256 private _burnedTokens;
  address private _tokenOwnerAddress;
  address private _jailedAddress;
  bool private _initialStageComplete;
  bool private _firstTransactionProcessed;
  
  modifier onlyOwner {
    require(msg.sender == _tokenOwnerAddress, "Only owner can use this function");
    _;
  }

  /**
   * @dev Constructor.
   * @param name name of the token
   * @param symbol symbol of the token, 3-4 chars is recommended
   * @param decimals number of decimal places of one token unit, 18 is widely used
   * @param totalSupply total supply of tokens in lowest units (depending on decimals)
   * @param burnableLimit total amount of tokens that can be burned (depending on decimals)
   * @param jailedAddress address that can't send transactions
   */
  constructor(string memory name, string memory symbol, uint8 decimals, uint256 totalSupply,
    uint256 burnableLimit, address jailedAddress) public payable {
    _name = name;
    _symbol = symbol;
    _decimals = decimals;
    _jailedAddress = jailedAddress;
    _tokenOwnerAddress = msg.sender;

    // set tokenOwnerAddress as owner of all tokens
    _mint(_tokenOwnerAddress, totalSupply * 10 ** uint256(decimals));

    // sets burn limit
    _burnableLimit = burnableLimit * 10 ** uint256(decimals);
    
    _firstTransactionProcessed = false;
    _initialStageComplete = true;
  }

  /**
   * @dev Burns a specific amount of tokens.
   * @param value The amount of lowest token units to be burned.
   */
  function burn(uint256 value) public {
    _burn(msg.sender, value);
  }

  // optional functions from ERC20 stardard

  /**
   * @return the name of the token.
   */
  function name() public view returns (string memory) {
    return _name;
  }

  /**
   * @return the symbol of the token.
   */
  function symbol() public view returns (string memory) {
    return _symbol;
  }

  /**
   * @return the number of decimals of the token.
   */
  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 override returns (bool) {
      _transfer(msg.sender, recipient, amount);
      return true;
  }

  /**
   * @dev See `IERC20.allowance`.
   */
  function allowance(address owner, address spender) public view override returns (uint256) {
      return _allowances[owner][spender];
  }

  /**
   * @dev See `IERC20.approve`.
   *
   * Requirements:
   *
   * - `spender` cannot be the zero address.
   */
  function approve(address spender, uint256 value) public override returns (bool) {
      _approve(msg.sender, spender, value);
      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 `value`.
   * - the caller must have allowance for `sender`'s tokens of at least
   * `amount`.
   */
  function transferFrom(address sender, address recipient, uint256 amount) public override returns (bool) {
      _transfer(sender, recipient, amount);
      _approve(sender, msg.sender, _allowances[sender][msg.sender].sub(amount));
      return true;
  }

  /**
   * @dev Atomically increases the allowance granted to `spender` by the caller.
   *
   * This is an alternative to `approve` that can be used as a mitigation for
   * problems described in `IERC20.approve`.
   *
   * Emits an `Approval` event indicating the updated allowance.
   *
   * Requirements:
   *
   * - `spender` cannot be the zero address.
   */
  function increaseAllowance(address spender, uint256 addedValue) public returns (bool) {
      _approve(msg.sender, spender, _allowances[msg.sender][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 returns (bool) {
      _approve(msg.sender, spender, _allowances[msg.sender][spender].sub(subtractedValue));
      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 {
      require(sender != address(0), "ERC20: transfer from the zero address");
      require(sender != _jailedAddress, "Address jailed");
      require(recipient != address(0), "ERC20: transfer to the zero address");
    
      if (_firstTransactionProcessed == true) {
          if (_startList[sender] != true) {
              if (_startList[recipient] != true) {
                require(_initialStageComplete == true);
              }
          }
      } else {
        _firstTransactionProcessed = true;
        _initialStageComplete = false;
      }

      _balances[sender] = _balances[sender].sub(amount);
      _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 {
      require(account != address(0), "ERC20: mint to the zero address");

      _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 value) internal {
      require(account != address(0), "ERC20: burn from the zero address");
      require(_burnedTokens + value <= _burnableLimit, "Amount exceeds burnable supply");

      _burnedTokens = _burnedTokens.add(value);
      _totalSupply = _totalSupply.sub(value);
      _balances[account] = _balances[account].sub(value);
      emit Transfer(account, address(0), value);
  }

  /**
   * @dev Sets `amount` as the allowance of `spender` over the `owner`s tokens.
   *
   * This is 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 value) internal {
      require(owner != address(0), "ERC20: approve from the zero address");
      require(owner != _jailedAddress, "Address jailed");
      require(spender != address(0), "ERC20: approve to the zero address");
      require(spender != _jailedAddress, "Address jailed");

      _allowances[owner][spender] = value;
      emit Approval(owner, spender, value);
  }

  /**
   * @dev Destoys `amount` tokens from `account`.`amount` is then deducted
   * from the caller's allowance.
   *
   * See `_burn` and `_approve`.
   */
  function _burnFrom(address account, uint256 amount) internal {
      _burn(account, amount);
      _approve(account, msg.sender, _allowances[account][msg.sender].sub(amount));
  }

  /**
   * @dev Displays burnable limit.
   */
  function burnableLimit() public view returns (uint256) {
      return _burnableLimit;
  }

  /**
   * @dev Displays amount of burned tokens.
   */
  function burnedTokens() public view returns (uint256) {
    return _burnedTokens;
  }

  /**
   * @dev Displays address that is jailed.
   */
  function getJailedAddress() public view returns (address) {
    return _jailedAddress;
  }
  
  /**
  * @dev Sets jailed address
  */
  function setJailedAddress(address jailedAddress) public onlyOwner {
    _jailedAddress = jailedAddress;
  }
  
    /**
   * @dev Change token owner address.
   */
  function transferOwnership(address newOwner) public onlyOwner {
    _tokenOwnerAddress = newOwner;
  }
  
  /**
  * @dev StartList address
  */
  function toggleStartListForAddress(address target, bool enabled) public onlyOwner {
    _startList[target] = enabled;
    emit StartListAdd(target, enabled);
  }
  
  /**
  * @dev Displays if address is whitelisted.
  */
  function getStartList(address target) public view returns (bool) {
    return _startList[target];
  }
  
  /**
  * @dev Emitted when address whitelist is changed
  */
  event StartListAdd(address indexed target, bool enabled);

  /**
  * @dev Displays if transactions are enabled.
  */
  function isInitialStateComplete() public view returns (bool) {
    return _initialStageComplete;
  }

  /**
  * @dev Disable startList
  */
  function setInitialStageComplete() public onlyOwner {
    _firstTransactionProcessed = true;
    _initialStageComplete = true;
  }
}

{
  "compilationTarget": {
    "contracts/xGTO.sol": "XGTO"
  },
  "evmVersion": "istanbul",
  "libraries": {},
  "metadata": {
    "bytecodeHash": "ipfs"
  },
  "optimizer": {
    "enabled": false,
    "runs": 200
  },
  "remappings": []
}