// Vulnerability label: external
pragma solidity 0.4.18;

contract ERC20Basic {
    function totalSupply() public view returns (uint256);
    function balanceOf(address who) public view returns (uint256);
    function transfer(address to, uint256 value) public returns (bool);
    event Transfer(address indexed from, address indexed to, uint256 value);
}

contract ERC20 is ERC20Basic {
    function allowance(address owner, address spender) public view returns (uint256);
    function transferFrom(address from, address to, uint256 value) public returns (bool);
    function approve(address spender, uint256 value) public returns (bool);
    event Approval(address indexed owner, address indexed spender, uint256 value);
}

library SafeMath {

    /**
    * @dev Multiplies two numbers, throws on overflow.
    */
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        if (a == 0) {
            return 0;
        }
        uint256 c = a * b;
        assert(c / a == b);
        return c;
    }

    /**
    * @dev Integer division of two numbers, truncating the quotient.
    */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        // assert(b > 0); // Solidity automatically throws when dividing by 0
        uint256 c = a / b;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold
        return c;
    }

    /**
    * @dev Substracts two numbers, throws on overflow (i.e. if subtrahend is greater than minuend).
    */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        assert(b <= a);
        return a - b;
    }

    /**
    * @dev Adds two numbers, throws on overflow.
    */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        assert(c >= a);
        return c;
    }
}

contract ERC223 {
    function transfer(address _to, uint256 _value, bytes _data) public returns (bool success);
}

contract ERC223Receiver {
/**
 * @dev Standard ERC223 function that will handle incoming token transfers.
 *
 * @param _from  Token sender address.
 * @param _value Amount of tokens.
 * @param _data  Transaction metadata.
 */
    function tokenFallback(address _from, uint256 _value, bytes _data) public;
}

contract BasicToken is ERC20Basic {
    using SafeMath for uint256;

    mapping(address => uint256) balances;

    uint256 totalSupply_;

    /**
    * @dev total number of tokens in existence
    */
    function totalSupply() public view returns (uint256) {
        return totalSupply_;
    }

    /**
    * @dev transfer token for a specified address
    * @param _to The address to transfer to.
    * @param _value The amount to be transferred.
    */
    function transfer(address _to, uint256 _value) public returns (bool) {
        require(_to != address(0));
        require(_value <= balances[msg.sender]);

        // SafeMath.sub will throw if there is not enough balance.
        balances[msg.sender] = balances[msg.sender].sub(_value);
        balances[_to] = balances[_to].add(_value);
        Transfer(msg.sender, _to, _value);
        return true;
    }

    /**
    * @dev Gets the balance of the specified address.
    * @param _owner The address to query the the balance of.
    * @return An uint256 representing the amount owned by the passed address.
    */
    function balanceOf(address _owner) public view returns (uint256 balance) {
        return balances[_owner];
    }

}

contract StandardToken is ERC20, BasicToken {

    mapping (address => mapping (address => uint256)) internal allowed;


    /**
     * @dev Transfer tokens from one address to another
     * @param _from address The address which you want to send tokens from
     * @param _to address The address which you want to transfer to
     * @param _value uint256 the amount of tokens to be transferred
     */
    function transferFrom(address _from, address _to, uint256 _value) public returns (bool) {
        require(_to != address(0));
        require(_value <= balances[_from]);
        require(_value <= allowed[_from][msg.sender]);

        balances[_from] = balances[_from].sub(_value);
        balances[_to] = balances[_to].add(_value);
        allowed[_from][msg.sender] = allowed[_from][msg.sender].sub(_value);
        Transfer(_from, _to, _value);
        return true;
    }

    /**
     * @dev Approve the passed address to spend the specified amount of tokens on behalf of msg.sender.
     *
     * 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
     * @param _spender The address which will spend the funds.
     * @param _value The amount of tokens to be spent.
     */
    function approve(address _spender, uint256 _value) public returns (bool) {
        allowed[msg.sender][_spender] = _value;
        Approval(msg.sender, _spender, _value);
        return true;
    }

    /**
     * @dev Function to check the amount of tokens that an owner allowed to a spender.
     * @param _owner address The address which owns the funds.
     * @param _spender address The address which will spend the funds.
     * @return A uint256 specifying the amount of tokens still available for the spender.
     */
    function allowance(address _owner, address _spender) public view returns (uint256) {
        return allowed[_owner][_spender];
    }

    /**
     * @dev Increase the amount of tokens that an owner allowed to a spender.
     *
     * approve should be called when allowed[_spender] == 0. To increment
     * allowed value is better to use this function to avoid 2 calls (and wait until
     * the first transaction is mined)
     * From MonolithDAO Token.sol
     * @param _spender The address which will spend the funds.
     * @param _addedValue The amount of tokens to increase the allowance by.
     */
    function increaseApproval(address _spender, uint256 _addedValue) public returns (bool) {
        allowed[msg.sender][_spender] = allowed[msg.sender][_spender].add(_addedValue);
        Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
        return true;
    }

    /**
     * @dev Decrease the amount of tokens that an owner allowed to a spender.
     *
     * approve should be called when allowed[_spender] == 0. To decrement
     * allowed value is better to use this function to avoid 2 calls (and wait until
     * the first transaction is mined)
     * From MonolithDAO Token.sol
     * @param _spender The address which will spend the funds.
     * @param _subtractedValue The amount of tokens to decrease the allowance by.
     */
    function decreaseApproval(address _spender, uint256 _subtractedValue) public returns (bool) {
        uint256 oldValue = allowed[msg.sender][_spender];
        if (_subtractedValue > oldValue) {
            allowed[msg.sender][_spender] = 0;
        } else {
            allowed[msg.sender][_spender] = oldValue.sub(_subtractedValue);
        }
        Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
        return true;
    }

}

contract Standard223Token is StandardToken, ERC223 {
    using SafeMath for uint256;

    /**
     * @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
     *
     * @param _to    Receiver address.
     * @param _value Amount of tokens that will be transferred.
     * @param _data  Transaction metadata.
    */
    function transfer(address _to, uint256 _value, bytes _data) public returns (bool success) {
        require(_to != address(0));
        require(_value <= balances[msg.sender]);

        if(isContract(_to)) {
            return transferToContract(_to, _value, _data);
        } else {
            return transferToAddress(_to, _value);
        }
    }

    /**
     * @dev Transfer the specified amount of tokens to the specified address.
     *      Invokes the `_custom_fallback` function if the recipient is a contract.
     *      The token transfer fails if the recipient is a contract
     *      but does not implement the `_custom_fallback` function
     *
     * @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, string _custom_fallback) public returns (bool success) {
        require(_to != address(0));
        require(_value <= balances[msg.sender]);

        if(isContract(_to)) {
            balances[msg.sender] = balances[msg.sender].sub(_value);
            balances[_to] = balances[_to].add(_value);
            /* solium-disable-next-line */
            assert(_to.call.value(0)(bytes4(keccak256(_custom_fallback)), msg.sender, _value, _data));
            Transfer(msg.sender, _to, _value);
            return true;
        } else {
            return transferToAddress(_to, _value);
        }
    }

    /**
     * @dev Transfer the specified amount of tokens to the specified address.
     *      Added due to backwards compatibility reasons.
     *
     * @param _to    Receiver address.
     * @param _value Amount of tokens that will be transferred.
    */
    function transfer(address _to, uint256 _value) public returns (bool success) {
        return transfer(_to, _value, new bytes(0));
    }

    function transferToAddress(address _to, uint _value) private returns (bool success) {
        balances[msg.sender] = balances[msg.sender].sub(_value);
        balances[_to] = balances[_to].add(_value);
        Transfer(msg.sender, _to, _value);
        return true;
    }

    function transferToContract(address _to, uint _value, bytes _data) private returns (bool success) {
        balances[msg.sender] = balances[msg.sender].sub(_value);
        balances[_to] = balances[_to].add(_value);
        ERC223Receiver reciever = ERC223Receiver(_to);
        reciever.tokenFallback(msg.sender, _value, _data);
        Transfer(msg.sender, _to, _value);
        return true;
    }

    /**
    * @dev Retrieve the size of the code on target address, this needs assembly.
    *
    * @param _addr  The address to check if it's a contract.
    *
    * @return is_contract   TRUE if it's a contract else false.
    */
    function isContract(address _addr) private view returns (bool is_contract) {
        uint256 length;
        /* solium-disable-next-line */
        assembly {
            length := extcodesize(_addr)
        }
        return length > 0;
    }
}

contract TrueToken is Standard223Token {

    string public name;
    string public symbol;
    uint8 public decimals;
    uint256 public INITIAL_SUPPLY = 25000000;   // 25 million

    function TrueToken() public {
        name = "TRUE";
        symbol = "TRUE";
        decimals = 18;

        totalSupply_ = INITIAL_SUPPLY * 10 ** uint256(decimals);
        balances[msg.sender] = totalSupply_;
    }
}