contract ERC223Token is ERC20, ERC223Basic {
    using SafeMath for uint256;

    mapping(address => uint256) balances; // List of user balances.

    /**
    * @dev protection against short address attack
    */
    modifier onlyPayloadSize(uint numwords) {
        assert(msg.data.length == numwords * 32 + 4);
        _;
    }

    /**
     * @dev Transfer the specified amount of tokens to the specified address.
     *      Invokes the `tokenFallback` function if the recipient is a contract.
     *      The token transfer fails if the recipient is a contract
     *      but does not implement the `tokenFallback` function
     *      or the fallback function to receive funds.
     *
     * @param _to    Receiver address.
     * @param _value Amount of tokens that will be transferred.
     * @param _data  Transaction metadata.
     */
    function transfer(address _to, uint _value, bytes _data) public onlyPayloadSize(3) {
        // Standard function transfer similar to ERC20 transfer with no _data .
        // Added due to backwards compatibility reasons .
        uint codeLength;
        require(_to != address(0));
        require(_value <= balances[msg.sender]);
        require(transfersEnabled);

        assembly {
        // Retrieve the size of the code on target address, this needs assembly .
            codeLength := extcodesize(_to)
        }

        balances[msg.sender] = balances[msg.sender].sub(_value);
        balances[_to] = balances[_to].add(_value);
        if(codeLength>0) {
            ERC223ReceivingContract receiver = ERC223ReceivingContract(_to);
            receiver.tokenFallback(msg.sender, _value, _data);
        }
        emit Transfer(msg.sender, _to, _value, _data);
    }

    /**
     * @dev Transfer the specified amount of tokens to the specified address.
     *      This function works the same with the previous one
     *      but doesn't contain `_data` param.
     *      Added due to backwards compatibility reasons.
     *
     * @param _to    Receiver address.
     * @param _value Amount of tokens that will be transferred.
     */
    function transfer(address _to, uint _value) public onlyPayloadSize(2) returns(bool) {
        uint codeLength;
        bytes memory empty;
        require(_to != address(0));
        require(_value <= balances[msg.sender]);
        require(transfersEnabled);

        assembly {
        // Retrieve the size of the code on target address, this needs assembly .
            codeLength := extcodesize(_to)
        }

        balances[msg.sender] = balances[msg.sender].sub(_value);
        balances[_to] = balances[_to].add(_value);
        if(codeLength>0) {
            ERC223ReceivingContract receiver = ERC223ReceivingContract(_to);
            receiver.tokenFallback(msg.sender, _value, empty);
        }
        emit Transfer(msg.sender, _to, _value);
        return true;
    }


    /**
     * @dev Returns balance of the `_owner`.
     *
     * @param _owner   The address whose balance will be returned.
     * @return balance Balance of the `_owner`.
     */
    function balanceOf(address _owner) public constant returns (uint256 balance) {
        return balances[_owner];
    }
}
function transfer(address _to, uint _value) public onlyPayloadSize(2) returns(bool) {
        uint codeLength;
        bytes memory empty;
        require(_to != address(0));
        require(_value <= balances[msg.sender]);
        require(transfersEnabled);

        assembly {
        // Retrieve the size of the code on target address, this needs assembly .
            codeLength := extcodesize(_to)
        }

        balances[msg.sender] = balances[msg.sender].sub(_value);
        balances[_to] = balances[_to].add(_value);
        if(codeLength>0) {
            ERC223ReceivingContract receiver = ERC223ReceivingContract(_to);
            receiver.tokenFallback(msg.sender, _value, empty);
        }
        emit Transfer(msg.sender, _to, _value);
        return true;
    }
/**
 * @dev Transfer the specified amount of tokens to the specified address.
 *      This function works the same with the previous one
 *      but doesn't contain `_data` param.
 *      Added due to backwards compatibility reasons.
 *
 * @param _to    Receiver address.
 * @param _value Amount of tokens that will be transferred.
 */